xref: /spdk/lib/nvmf/rdma.c (revision aa7a13afc7fbc0663c32833e4a5b3b3606d86fca)
1 /*-
2  *   BSD LICENSE
3  *
4  *   Copyright (c) Intel Corporation. All rights reserved.
5  *   Copyright (c) 2019, 2020 Mellanox Technologies LTD. All rights reserved.
6  *
7  *   Redistribution and use in source and binary forms, with or without
8  *   modification, are permitted provided that the following conditions
9  *   are met:
10  *
11  *     * Redistributions of source code must retain the above copyright
12  *       notice, this list of conditions and the following disclaimer.
13  *     * Redistributions in binary form must reproduce the above copyright
14  *       notice, this list of conditions and the following disclaimer in
15  *       the documentation and/or other materials provided with the
16  *       distribution.
17  *     * Neither the name of Intel Corporation nor the names of its
18  *       contributors may be used to endorse or promote products derived
19  *       from this software without specific prior written permission.
20  *
21  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
24  *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
25  *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
26  *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
27  *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28  *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29  *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30  *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
31  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32  */
33 
34 #include "spdk/stdinc.h"
35 
36 #include <infiniband/verbs.h>
37 #include <rdma/rdma_cma.h>
38 #include <rdma/rdma_verbs.h>
39 
40 #include "spdk/config.h"
41 #include "spdk/thread.h"
42 #include "spdk/likely.h"
43 #include "spdk/nvmf_transport.h"
44 #include "spdk/string.h"
45 #include "spdk/trace.h"
46 #include "spdk/util.h"
47 
48 #include "spdk_internal/assert.h"
49 #include "spdk_internal/log.h"
50 
51 struct spdk_nvme_rdma_hooks g_nvmf_hooks = {};
52 const struct spdk_nvmf_transport_ops spdk_nvmf_transport_rdma;
53 
54 /*
55  RDMA Connection Resource Defaults
56  */
57 #define NVMF_DEFAULT_TX_SGE		SPDK_NVMF_MAX_SGL_ENTRIES
58 #define NVMF_DEFAULT_RSP_SGE		1
59 #define NVMF_DEFAULT_RX_SGE		2
60 
61 /* The RDMA completion queue size */
62 #define DEFAULT_NVMF_RDMA_CQ_SIZE	4096
63 #define MAX_WR_PER_QP(queue_depth)	(queue_depth * 3 + 2)
64 
65 /* Timeout for destroying defunct rqpairs */
66 #define NVMF_RDMA_QPAIR_DESTROY_TIMEOUT_US	4000000
67 
68 static int g_spdk_nvmf_ibv_query_mask =
69 	IBV_QP_STATE |
70 	IBV_QP_PKEY_INDEX |
71 	IBV_QP_PORT |
72 	IBV_QP_ACCESS_FLAGS |
73 	IBV_QP_AV |
74 	IBV_QP_PATH_MTU |
75 	IBV_QP_DEST_QPN |
76 	IBV_QP_RQ_PSN |
77 	IBV_QP_MAX_DEST_RD_ATOMIC |
78 	IBV_QP_MIN_RNR_TIMER |
79 	IBV_QP_SQ_PSN |
80 	IBV_QP_TIMEOUT |
81 	IBV_QP_RETRY_CNT |
82 	IBV_QP_RNR_RETRY |
83 	IBV_QP_MAX_QP_RD_ATOMIC;
84 
85 enum spdk_nvmf_rdma_request_state {
86 	/* The request is not currently in use */
87 	RDMA_REQUEST_STATE_FREE = 0,
88 
89 	/* Initial state when request first received */
90 	RDMA_REQUEST_STATE_NEW,
91 
92 	/* The request is queued until a data buffer is available. */
93 	RDMA_REQUEST_STATE_NEED_BUFFER,
94 
95 	/* The request is waiting on RDMA queue depth availability
96 	 * to transfer data from the host to the controller.
97 	 */
98 	RDMA_REQUEST_STATE_DATA_TRANSFER_TO_CONTROLLER_PENDING,
99 
100 	/* The request is currently transferring data from the host to the controller. */
101 	RDMA_REQUEST_STATE_TRANSFERRING_HOST_TO_CONTROLLER,
102 
103 	/* The request is ready to execute at the block device */
104 	RDMA_REQUEST_STATE_READY_TO_EXECUTE,
105 
106 	/* The request is currently executing at the block device */
107 	RDMA_REQUEST_STATE_EXECUTING,
108 
109 	/* The request finished executing at the block device */
110 	RDMA_REQUEST_STATE_EXECUTED,
111 
112 	/* The request is waiting on RDMA queue depth availability
113 	 * to transfer data from the controller to the host.
114 	 */
115 	RDMA_REQUEST_STATE_DATA_TRANSFER_TO_HOST_PENDING,
116 
117 	/* The request is ready to send a completion */
118 	RDMA_REQUEST_STATE_READY_TO_COMPLETE,
119 
120 	/* The request is currently transferring data from the controller to the host. */
121 	RDMA_REQUEST_STATE_TRANSFERRING_CONTROLLER_TO_HOST,
122 
123 	/* The request currently has an outstanding completion without an
124 	 * associated data transfer.
125 	 */
126 	RDMA_REQUEST_STATE_COMPLETING,
127 
128 	/* The request completed and can be marked free. */
129 	RDMA_REQUEST_STATE_COMPLETED,
130 
131 	/* Terminator */
132 	RDMA_REQUEST_NUM_STATES,
133 };
134 
135 #define OBJECT_NVMF_RDMA_IO				0x40
136 
137 #define TRACE_GROUP_NVMF_RDMA				0x4
138 #define TRACE_RDMA_REQUEST_STATE_NEW					SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0x0)
139 #define TRACE_RDMA_REQUEST_STATE_NEED_BUFFER				SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0x1)
140 #define TRACE_RDMA_REQUEST_STATE_DATA_TRANSFER_TO_CONTROLLER_PENDING	SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0x2)
141 #define TRACE_RDMA_REQUEST_STATE_TRANSFERRING_HOST_TO_CONTROLLER	SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0x3)
142 #define TRACE_RDMA_REQUEST_STATE_READY_TO_EXECUTE			SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0x4)
143 #define TRACE_RDMA_REQUEST_STATE_EXECUTING				SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0x5)
144 #define TRACE_RDMA_REQUEST_STATE_EXECUTED				SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0x6)
145 #define TRACE_RDMA_REQUEST_STATE_DATA_TRANSFER_TO_HOST_PENDING		SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0x7)
146 #define TRACE_RDMA_REQUEST_STATE_READY_TO_COMPLETE			SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0x8)
147 #define TRACE_RDMA_REQUEST_STATE_TRANSFERRING_CONTROLLER_TO_HOST	SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0x9)
148 #define TRACE_RDMA_REQUEST_STATE_COMPLETING				SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0xA)
149 #define TRACE_RDMA_REQUEST_STATE_COMPLETED				SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0xB)
150 #define TRACE_RDMA_QP_CREATE						SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0xC)
151 #define TRACE_RDMA_IBV_ASYNC_EVENT					SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0xD)
152 #define TRACE_RDMA_CM_ASYNC_EVENT					SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0xE)
153 #define TRACE_RDMA_QP_STATE_CHANGE					SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0xF)
154 #define TRACE_RDMA_QP_DISCONNECT					SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0x10)
155 #define TRACE_RDMA_QP_DESTROY						SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0x11)
156 
157 SPDK_TRACE_REGISTER_FN(nvmf_trace, "nvmf_rdma", TRACE_GROUP_NVMF_RDMA)
158 {
159 	spdk_trace_register_object(OBJECT_NVMF_RDMA_IO, 'r');
160 	spdk_trace_register_description("RDMA_REQ_NEW", TRACE_RDMA_REQUEST_STATE_NEW,
161 					OWNER_NONE, OBJECT_NVMF_RDMA_IO, 1, 1, "cmid:   ");
162 	spdk_trace_register_description("RDMA_REQ_NEED_BUFFER", TRACE_RDMA_REQUEST_STATE_NEED_BUFFER,
163 					OWNER_NONE, OBJECT_NVMF_RDMA_IO, 0, 1, "cmid:   ");
164 	spdk_trace_register_description("RDMA_REQ_TX_PENDING_C2H",
165 					TRACE_RDMA_REQUEST_STATE_DATA_TRANSFER_TO_HOST_PENDING,
166 					OWNER_NONE, OBJECT_NVMF_RDMA_IO, 0, 1, "cmid:   ");
167 	spdk_trace_register_description("RDMA_REQ_TX_PENDING_H2C",
168 					TRACE_RDMA_REQUEST_STATE_DATA_TRANSFER_TO_CONTROLLER_PENDING,
169 					OWNER_NONE, OBJECT_NVMF_RDMA_IO, 0, 1, "cmid:   ");
170 	spdk_trace_register_description("RDMA_REQ_TX_H2C",
171 					TRACE_RDMA_REQUEST_STATE_TRANSFERRING_HOST_TO_CONTROLLER,
172 					OWNER_NONE, OBJECT_NVMF_RDMA_IO, 0, 1, "cmid:   ");
173 	spdk_trace_register_description("RDMA_REQ_RDY_TO_EXECUTE",
174 					TRACE_RDMA_REQUEST_STATE_READY_TO_EXECUTE,
175 					OWNER_NONE, OBJECT_NVMF_RDMA_IO, 0, 1, "cmid:   ");
176 	spdk_trace_register_description("RDMA_REQ_EXECUTING",
177 					TRACE_RDMA_REQUEST_STATE_EXECUTING,
178 					OWNER_NONE, OBJECT_NVMF_RDMA_IO, 0, 1, "cmid:   ");
179 	spdk_trace_register_description("RDMA_REQ_EXECUTED",
180 					TRACE_RDMA_REQUEST_STATE_EXECUTED,
181 					OWNER_NONE, OBJECT_NVMF_RDMA_IO, 0, 1, "cmid:   ");
182 	spdk_trace_register_description("RDMA_REQ_RDY_TO_COMPL",
183 					TRACE_RDMA_REQUEST_STATE_READY_TO_COMPLETE,
184 					OWNER_NONE, OBJECT_NVMF_RDMA_IO, 0, 1, "cmid:   ");
185 	spdk_trace_register_description("RDMA_REQ_COMPLETING_C2H",
186 					TRACE_RDMA_REQUEST_STATE_TRANSFERRING_CONTROLLER_TO_HOST,
187 					OWNER_NONE, OBJECT_NVMF_RDMA_IO, 0, 1, "cmid:   ");
188 	spdk_trace_register_description("RDMA_REQ_COMPLETING",
189 					TRACE_RDMA_REQUEST_STATE_COMPLETING,
190 					OWNER_NONE, OBJECT_NVMF_RDMA_IO, 0, 1, "cmid:   ");
191 	spdk_trace_register_description("RDMA_REQ_COMPLETED",
192 					TRACE_RDMA_REQUEST_STATE_COMPLETED,
193 					OWNER_NONE, OBJECT_NVMF_RDMA_IO, 0, 1, "cmid:   ");
194 
195 	spdk_trace_register_description("RDMA_QP_CREATE", TRACE_RDMA_QP_CREATE,
196 					OWNER_NONE, OBJECT_NONE, 0, 0, "");
197 	spdk_trace_register_description("RDMA_IBV_ASYNC_EVENT", TRACE_RDMA_IBV_ASYNC_EVENT,
198 					OWNER_NONE, OBJECT_NONE, 0, 0, "type:   ");
199 	spdk_trace_register_description("RDMA_CM_ASYNC_EVENT", TRACE_RDMA_CM_ASYNC_EVENT,
200 					OWNER_NONE, OBJECT_NONE, 0, 0, "type:   ");
201 	spdk_trace_register_description("RDMA_QP_STATE_CHANGE", TRACE_RDMA_QP_STATE_CHANGE,
202 					OWNER_NONE, OBJECT_NONE, 0, 1, "state:  ");
203 	spdk_trace_register_description("RDMA_QP_DISCONNECT", TRACE_RDMA_QP_DISCONNECT,
204 					OWNER_NONE, OBJECT_NONE, 0, 0, "");
205 	spdk_trace_register_description("RDMA_QP_DESTROY", TRACE_RDMA_QP_DESTROY,
206 					OWNER_NONE, OBJECT_NONE, 0, 0, "");
207 }
208 
209 enum spdk_nvmf_rdma_wr_type {
210 	RDMA_WR_TYPE_RECV,
211 	RDMA_WR_TYPE_SEND,
212 	RDMA_WR_TYPE_DATA,
213 };
214 
215 struct spdk_nvmf_rdma_wr {
216 	enum spdk_nvmf_rdma_wr_type	type;
217 };
218 
219 /* This structure holds commands as they are received off the wire.
220  * It must be dynamically paired with a full request object
221  * (spdk_nvmf_rdma_request) to service a request. It is separate
222  * from the request because RDMA does not appear to order
223  * completions, so occasionally we'll get a new incoming
224  * command when there aren't any free request objects.
225  */
226 struct spdk_nvmf_rdma_recv {
227 	struct ibv_recv_wr			wr;
228 	struct ibv_sge				sgl[NVMF_DEFAULT_RX_SGE];
229 
230 	struct spdk_nvmf_rdma_qpair		*qpair;
231 
232 	/* In-capsule data buffer */
233 	uint8_t					*buf;
234 
235 	struct spdk_nvmf_rdma_wr		rdma_wr;
236 	uint64_t				receive_tsc;
237 
238 	STAILQ_ENTRY(spdk_nvmf_rdma_recv)	link;
239 };
240 
241 struct spdk_nvmf_rdma_request_data {
242 	struct spdk_nvmf_rdma_wr	rdma_wr;
243 	struct ibv_send_wr		wr;
244 	struct ibv_sge			sgl[SPDK_NVMF_MAX_SGL_ENTRIES];
245 };
246 
247 struct spdk_nvmf_rdma_request {
248 	struct spdk_nvmf_request		req;
249 
250 	enum spdk_nvmf_rdma_request_state	state;
251 
252 	struct spdk_nvmf_rdma_recv		*recv;
253 
254 	struct {
255 		struct spdk_nvmf_rdma_wr	rdma_wr;
256 		struct	ibv_send_wr		wr;
257 		struct	ibv_sge			sgl[NVMF_DEFAULT_RSP_SGE];
258 	} rsp;
259 
260 	struct spdk_nvmf_rdma_request_data	data;
261 
262 	uint32_t				iovpos;
263 
264 	uint32_t				num_outstanding_data_wr;
265 	uint64_t				receive_tsc;
266 
267 	STAILQ_ENTRY(spdk_nvmf_rdma_request)	state_link;
268 };
269 
270 enum spdk_nvmf_rdma_qpair_disconnect_flags {
271 	RDMA_QP_DISCONNECTING		= 1,
272 	RDMA_QP_RECV_DRAINED		= 1 << 1,
273 	RDMA_QP_SEND_DRAINED		= 1 << 2
274 };
275 
276 struct spdk_nvmf_rdma_resource_opts {
277 	struct spdk_nvmf_rdma_qpair	*qpair;
278 	/* qp points either to an ibv_qp object or an ibv_srq object depending on the value of shared. */
279 	void				*qp;
280 	struct ibv_pd			*pd;
281 	uint32_t			max_queue_depth;
282 	uint32_t			in_capsule_data_size;
283 	bool				shared;
284 };
285 
286 struct spdk_nvmf_send_wr_list {
287 	struct ibv_send_wr	*first;
288 	struct ibv_send_wr	*last;
289 };
290 
291 struct spdk_nvmf_recv_wr_list {
292 	struct ibv_recv_wr	*first;
293 	struct ibv_recv_wr	*last;
294 };
295 
296 struct spdk_nvmf_rdma_resources {
297 	/* Array of size "max_queue_depth" containing RDMA requests. */
298 	struct spdk_nvmf_rdma_request		*reqs;
299 
300 	/* Array of size "max_queue_depth" containing RDMA recvs. */
301 	struct spdk_nvmf_rdma_recv		*recvs;
302 
303 	/* Array of size "max_queue_depth" containing 64 byte capsules
304 	 * used for receive.
305 	 */
306 	union nvmf_h2c_msg			*cmds;
307 	struct ibv_mr				*cmds_mr;
308 
309 	/* Array of size "max_queue_depth" containing 16 byte completions
310 	 * to be sent back to the user.
311 	 */
312 	union nvmf_c2h_msg			*cpls;
313 	struct ibv_mr				*cpls_mr;
314 
315 	/* Array of size "max_queue_depth * InCapsuleDataSize" containing
316 	 * buffers to be used for in capsule data.
317 	 */
318 	void					*bufs;
319 	struct ibv_mr				*bufs_mr;
320 
321 	/* The list of pending recvs to transfer */
322 	struct spdk_nvmf_recv_wr_list		recvs_to_post;
323 
324 	/* Receives that are waiting for a request object */
325 	STAILQ_HEAD(, spdk_nvmf_rdma_recv)	incoming_queue;
326 
327 	/* Queue to track free requests */
328 	STAILQ_HEAD(, spdk_nvmf_rdma_request)	free_queue;
329 };
330 
331 typedef void (*spdk_nvmf_rdma_qpair_ibv_event)(struct spdk_nvmf_rdma_qpair *rqpair);
332 
333 struct spdk_nvmf_rdma_ibv_event_ctx {
334 	struct spdk_nvmf_rdma_qpair			*rqpair;
335 	spdk_nvmf_rdma_qpair_ibv_event			cb_fn;
336 	/* Link to other ibv events associated with this qpair */
337 	STAILQ_ENTRY(spdk_nvmf_rdma_ibv_event_ctx)	link;
338 };
339 
340 struct spdk_nvmf_rdma_qpair {
341 	struct spdk_nvmf_qpair			qpair;
342 
343 	struct spdk_nvmf_rdma_device		*device;
344 	struct spdk_nvmf_rdma_poller		*poller;
345 
346 	struct rdma_cm_id			*cm_id;
347 	struct ibv_srq				*srq;
348 	struct rdma_cm_id			*listen_id;
349 
350 	/* The maximum number of I/O outstanding on this connection at one time */
351 	uint16_t				max_queue_depth;
352 
353 	/* The maximum number of active RDMA READ and ATOMIC operations at one time */
354 	uint16_t				max_read_depth;
355 
356 	/* The maximum number of RDMA SEND operations at one time */
357 	uint32_t				max_send_depth;
358 
359 	/* The current number of outstanding WRs from this qpair's
360 	 * recv queue. Should not exceed device->attr.max_queue_depth.
361 	 */
362 	uint16_t				current_recv_depth;
363 
364 	/* The current number of active RDMA READ operations */
365 	uint16_t				current_read_depth;
366 
367 	/* The current number of posted WRs from this qpair's
368 	 * send queue. Should not exceed max_send_depth.
369 	 */
370 	uint32_t				current_send_depth;
371 
372 	/* The maximum number of SGEs per WR on the send queue */
373 	uint32_t				max_send_sge;
374 
375 	/* The maximum number of SGEs per WR on the recv queue */
376 	uint32_t				max_recv_sge;
377 
378 	/* The list of pending send requests for a transfer */
379 	struct spdk_nvmf_send_wr_list		sends_to_post;
380 
381 	struct spdk_nvmf_rdma_resources		*resources;
382 
383 	STAILQ_HEAD(, spdk_nvmf_rdma_request)	pending_rdma_read_queue;
384 
385 	STAILQ_HEAD(, spdk_nvmf_rdma_request)	pending_rdma_write_queue;
386 
387 	/* Number of requests not in the free state */
388 	uint32_t				qd;
389 
390 	TAILQ_ENTRY(spdk_nvmf_rdma_qpair)	link;
391 
392 	STAILQ_ENTRY(spdk_nvmf_rdma_qpair)	recv_link;
393 
394 	STAILQ_ENTRY(spdk_nvmf_rdma_qpair)	send_link;
395 
396 	/* IBV queue pair attributes: they are used to manage
397 	 * qp state and recover from errors.
398 	 */
399 	enum ibv_qp_state			ibv_state;
400 
401 	uint32_t				disconnect_flags;
402 
403 	/* Poller registered in case the qpair doesn't properly
404 	 * complete the qpair destruct process and becomes defunct.
405 	 */
406 
407 	struct spdk_poller			*destruct_poller;
408 
409 	/* List of ibv async events */
410 	STAILQ_HEAD(, spdk_nvmf_rdma_ibv_event_ctx)	ibv_events;
411 
412 	/* There are several ways a disconnect can start on a qpair
413 	 * and they are not all mutually exclusive. It is important
414 	 * that we only initialize one of these paths.
415 	 */
416 	bool					disconnect_started;
417 	/* Lets us know that we have received the last_wqe event. */
418 	bool					last_wqe_reached;
419 };
420 
421 struct spdk_nvmf_rdma_poller_stat {
422 	uint64_t				completions;
423 	uint64_t				polls;
424 	uint64_t				requests;
425 	uint64_t				request_latency;
426 	uint64_t				pending_free_request;
427 	uint64_t				pending_rdma_read;
428 	uint64_t				pending_rdma_write;
429 };
430 
431 struct spdk_nvmf_rdma_poller {
432 	struct spdk_nvmf_rdma_device		*device;
433 	struct spdk_nvmf_rdma_poll_group	*group;
434 
435 	int					num_cqe;
436 	int					required_num_wr;
437 	struct ibv_cq				*cq;
438 
439 	/* The maximum number of I/O outstanding on the shared receive queue at one time */
440 	uint16_t				max_srq_depth;
441 
442 	/* Shared receive queue */
443 	struct ibv_srq				*srq;
444 
445 	struct spdk_nvmf_rdma_resources		*resources;
446 	struct spdk_nvmf_rdma_poller_stat	stat;
447 
448 	TAILQ_HEAD(, spdk_nvmf_rdma_qpair)	qpairs;
449 
450 	STAILQ_HEAD(, spdk_nvmf_rdma_qpair)	qpairs_pending_recv;
451 
452 	STAILQ_HEAD(, spdk_nvmf_rdma_qpair)	qpairs_pending_send;
453 
454 	TAILQ_ENTRY(spdk_nvmf_rdma_poller)	link;
455 };
456 
457 struct spdk_nvmf_rdma_poll_group_stat {
458 	uint64_t				pending_data_buffer;
459 };
460 
461 struct spdk_nvmf_rdma_poll_group {
462 	struct spdk_nvmf_transport_poll_group		group;
463 	struct spdk_nvmf_rdma_poll_group_stat		stat;
464 	TAILQ_HEAD(, spdk_nvmf_rdma_poller)		pollers;
465 	TAILQ_ENTRY(spdk_nvmf_rdma_poll_group)		link;
466 	/*
467 	 * buffers which are split across multiple RDMA
468 	 * memory regions cannot be used by this transport.
469 	 */
470 	STAILQ_HEAD(, spdk_nvmf_transport_pg_cache_buf)	retired_bufs;
471 };
472 
473 struct spdk_nvmf_rdma_conn_sched {
474 	struct spdk_nvmf_rdma_poll_group *next_admin_pg;
475 	struct spdk_nvmf_rdma_poll_group *next_io_pg;
476 };
477 
478 /* Assuming rdma_cm uses just one protection domain per ibv_context. */
479 struct spdk_nvmf_rdma_device {
480 	struct ibv_device_attr			attr;
481 	struct ibv_context			*context;
482 
483 	struct spdk_mem_map			*map;
484 	struct ibv_pd				*pd;
485 
486 	int					num_srq;
487 
488 	TAILQ_ENTRY(spdk_nvmf_rdma_device)	link;
489 };
490 
491 struct spdk_nvmf_rdma_port {
492 	struct spdk_nvme_transport_id		trid;
493 	struct rdma_cm_id			*id;
494 	struct spdk_nvmf_rdma_device		*device;
495 	uint32_t				ref;
496 	TAILQ_ENTRY(spdk_nvmf_rdma_port)	link;
497 };
498 
499 struct spdk_nvmf_rdma_transport {
500 	struct spdk_nvmf_transport	transport;
501 
502 	struct spdk_nvmf_rdma_conn_sched conn_sched;
503 
504 	struct rdma_event_channel	*event_channel;
505 
506 	struct spdk_mempool		*data_wr_pool;
507 
508 	pthread_mutex_t			lock;
509 
510 	/* fields used to poll RDMA/IB events */
511 	nfds_t			npoll_fds;
512 	struct pollfd		*poll_fds;
513 
514 	TAILQ_HEAD(, spdk_nvmf_rdma_device)	devices;
515 	TAILQ_HEAD(, spdk_nvmf_rdma_port)	ports;
516 	TAILQ_HEAD(, spdk_nvmf_rdma_poll_group)	poll_groups;
517 };
518 
519 static inline void
520 spdk_nvmf_rdma_start_disconnect(struct spdk_nvmf_rdma_qpair *rqpair);
521 
522 static bool
523 spdk_nvmf_rdma_request_process(struct spdk_nvmf_rdma_transport *rtransport,
524 			       struct spdk_nvmf_rdma_request *rdma_req);
525 
526 static inline int
527 spdk_nvmf_rdma_check_ibv_state(enum ibv_qp_state state)
528 {
529 	switch (state) {
530 	case IBV_QPS_RESET:
531 	case IBV_QPS_INIT:
532 	case IBV_QPS_RTR:
533 	case IBV_QPS_RTS:
534 	case IBV_QPS_SQD:
535 	case IBV_QPS_SQE:
536 	case IBV_QPS_ERR:
537 		return 0;
538 	default:
539 		return -1;
540 	}
541 }
542 
543 static inline enum spdk_nvme_media_error_status_code
544 spdk_nvmf_rdma_dif_error_to_compl_status(uint8_t err_type) {
545 	enum spdk_nvme_media_error_status_code result;
546 	switch (err_type)
547 	{
548 	case SPDK_DIF_REFTAG_ERROR:
549 		result = SPDK_NVME_SC_REFERENCE_TAG_CHECK_ERROR;
550 		break;
551 	case SPDK_DIF_APPTAG_ERROR:
552 		result = SPDK_NVME_SC_APPLICATION_TAG_CHECK_ERROR;
553 		break;
554 	case SPDK_DIF_GUARD_ERROR:
555 		result = SPDK_NVME_SC_GUARD_CHECK_ERROR;
556 		break;
557 	default:
558 		SPDK_UNREACHABLE();
559 	}
560 
561 	return result;
562 }
563 
564 static enum ibv_qp_state
565 spdk_nvmf_rdma_update_ibv_state(struct spdk_nvmf_rdma_qpair *rqpair) {
566 	enum ibv_qp_state old_state, new_state;
567 	struct ibv_qp_attr qp_attr;
568 	struct ibv_qp_init_attr init_attr;
569 	int rc;
570 
571 	old_state = rqpair->ibv_state;
572 	rc = ibv_query_qp(rqpair->cm_id->qp, &qp_attr,
573 			  g_spdk_nvmf_ibv_query_mask, &init_attr);
574 
575 	if (rc)
576 	{
577 		SPDK_ERRLOG("Failed to get updated RDMA queue pair state!\n");
578 		return IBV_QPS_ERR + 1;
579 	}
580 
581 	new_state = qp_attr.qp_state;
582 	rqpair->ibv_state = new_state;
583 	qp_attr.ah_attr.port_num = qp_attr.port_num;
584 
585 	rc = spdk_nvmf_rdma_check_ibv_state(new_state);
586 	if (rc)
587 	{
588 		SPDK_ERRLOG("QP#%d: bad state updated: %u, maybe hardware issue\n", rqpair->qpair.qid, new_state);
589 		/*
590 		 * IBV_QPS_UNKNOWN undefined if lib version smaller than libibverbs-1.1.8
591 		 * IBV_QPS_UNKNOWN is the enum element after IBV_QPS_ERR
592 		 */
593 		return IBV_QPS_ERR + 1;
594 	}
595 
596 	if (old_state != new_state)
597 	{
598 		spdk_trace_record(TRACE_RDMA_QP_STATE_CHANGE, 0, 0,
599 				  (uintptr_t)rqpair->cm_id, new_state);
600 	}
601 	return new_state;
602 }
603 
604 static const char *str_ibv_qp_state[] = {
605 	"IBV_QPS_RESET",
606 	"IBV_QPS_INIT",
607 	"IBV_QPS_RTR",
608 	"IBV_QPS_RTS",
609 	"IBV_QPS_SQD",
610 	"IBV_QPS_SQE",
611 	"IBV_QPS_ERR",
612 	"IBV_QPS_UNKNOWN"
613 };
614 
615 static int
616 spdk_nvmf_rdma_set_ibv_state(struct spdk_nvmf_rdma_qpair *rqpair,
617 			     enum ibv_qp_state new_state)
618 {
619 	struct ibv_qp_attr qp_attr;
620 	struct ibv_qp_init_attr init_attr;
621 	int rc;
622 	enum ibv_qp_state state;
623 	static int attr_mask_rc[] = {
624 		[IBV_QPS_RESET] = IBV_QP_STATE,
625 		[IBV_QPS_INIT] = (IBV_QP_STATE |
626 				  IBV_QP_PKEY_INDEX |
627 				  IBV_QP_PORT |
628 				  IBV_QP_ACCESS_FLAGS),
629 		[IBV_QPS_RTR] = (IBV_QP_STATE |
630 				 IBV_QP_AV |
631 				 IBV_QP_PATH_MTU |
632 				 IBV_QP_DEST_QPN |
633 				 IBV_QP_RQ_PSN |
634 				 IBV_QP_MAX_DEST_RD_ATOMIC |
635 				 IBV_QP_MIN_RNR_TIMER),
636 		[IBV_QPS_RTS] = (IBV_QP_STATE |
637 				 IBV_QP_SQ_PSN |
638 				 IBV_QP_TIMEOUT |
639 				 IBV_QP_RETRY_CNT |
640 				 IBV_QP_RNR_RETRY |
641 				 IBV_QP_MAX_QP_RD_ATOMIC),
642 		[IBV_QPS_SQD] = IBV_QP_STATE,
643 		[IBV_QPS_SQE] = IBV_QP_STATE,
644 		[IBV_QPS_ERR] = IBV_QP_STATE,
645 	};
646 
647 	rc = spdk_nvmf_rdma_check_ibv_state(new_state);
648 	if (rc) {
649 		SPDK_ERRLOG("QP#%d: bad state requested: %u\n",
650 			    rqpair->qpair.qid, new_state);
651 		return rc;
652 	}
653 
654 	rc = ibv_query_qp(rqpair->cm_id->qp, &qp_attr,
655 			  g_spdk_nvmf_ibv_query_mask, &init_attr);
656 
657 	if (rc) {
658 		SPDK_ERRLOG("Failed to get updated RDMA queue pair state!\n");
659 	}
660 
661 	qp_attr.cur_qp_state = rqpair->ibv_state;
662 	qp_attr.qp_state = new_state;
663 
664 	rc = ibv_modify_qp(rqpair->cm_id->qp, &qp_attr,
665 			   attr_mask_rc[new_state]);
666 
667 	if (rc) {
668 		SPDK_ERRLOG("QP#%d: failed to set state to: %s, %d (%s)\n",
669 			    rqpair->qpair.qid, str_ibv_qp_state[new_state], errno, strerror(errno));
670 		return rc;
671 	}
672 
673 	state = spdk_nvmf_rdma_update_ibv_state(rqpair);
674 
675 	if (state != new_state) {
676 		SPDK_ERRLOG("QP#%d: expected state: %s, actual state: %s\n",
677 			    rqpair->qpair.qid, str_ibv_qp_state[new_state],
678 			    str_ibv_qp_state[state]);
679 		return -1;
680 	}
681 	SPDK_DEBUGLOG(SPDK_LOG_RDMA, "IBV QP#%u changed to: %s\n", rqpair->qpair.qid,
682 		      str_ibv_qp_state[state]);
683 	return 0;
684 }
685 
686 static void
687 nvmf_rdma_request_free_data(struct spdk_nvmf_rdma_request *rdma_req,
688 			    struct spdk_nvmf_rdma_transport *rtransport)
689 {
690 	struct spdk_nvmf_rdma_request_data	*data_wr;
691 	struct ibv_send_wr			*next_send_wr;
692 	uint64_t				req_wrid;
693 
694 	rdma_req->num_outstanding_data_wr = 0;
695 	data_wr = &rdma_req->data;
696 	req_wrid = data_wr->wr.wr_id;
697 	while (data_wr && data_wr->wr.wr_id == req_wrid) {
698 		memset(data_wr->sgl, 0, sizeof(data_wr->wr.sg_list[0]) * data_wr->wr.num_sge);
699 		data_wr->wr.num_sge = 0;
700 		next_send_wr = data_wr->wr.next;
701 		if (data_wr != &rdma_req->data) {
702 			spdk_mempool_put(rtransport->data_wr_pool, data_wr);
703 		}
704 		data_wr = (!next_send_wr || next_send_wr == &rdma_req->rsp.wr) ? NULL :
705 			  SPDK_CONTAINEROF(next_send_wr, struct spdk_nvmf_rdma_request_data, wr);
706 	}
707 }
708 
709 static void
710 nvmf_rdma_dump_request(struct spdk_nvmf_rdma_request *req)
711 {
712 	SPDK_ERRLOG("\t\tRequest Data From Pool: %d\n", req->req.data_from_pool);
713 	if (req->req.cmd) {
714 		SPDK_ERRLOG("\t\tRequest opcode: %d\n", req->req.cmd->nvmf_cmd.opcode);
715 	}
716 	if (req->recv) {
717 		SPDK_ERRLOG("\t\tRequest recv wr_id%lu\n", req->recv->wr.wr_id);
718 	}
719 }
720 
721 static void
722 nvmf_rdma_dump_qpair_contents(struct spdk_nvmf_rdma_qpair *rqpair)
723 {
724 	int i;
725 
726 	SPDK_ERRLOG("Dumping contents of queue pair (QID %d)\n", rqpair->qpair.qid);
727 	for (i = 0; i < rqpair->max_queue_depth; i++) {
728 		if (rqpair->resources->reqs[i].state != RDMA_REQUEST_STATE_FREE) {
729 			nvmf_rdma_dump_request(&rqpair->resources->reqs[i]);
730 		}
731 	}
732 }
733 
734 static void
735 nvmf_rdma_resources_destroy(struct spdk_nvmf_rdma_resources *resources)
736 {
737 	if (resources->cmds_mr) {
738 		ibv_dereg_mr(resources->cmds_mr);
739 	}
740 
741 	if (resources->cpls_mr) {
742 		ibv_dereg_mr(resources->cpls_mr);
743 	}
744 
745 	if (resources->bufs_mr) {
746 		ibv_dereg_mr(resources->bufs_mr);
747 	}
748 
749 	spdk_free(resources->cmds);
750 	spdk_free(resources->cpls);
751 	spdk_free(resources->bufs);
752 	free(resources->reqs);
753 	free(resources->recvs);
754 	free(resources);
755 }
756 
757 
758 static struct spdk_nvmf_rdma_resources *
759 nvmf_rdma_resources_create(struct spdk_nvmf_rdma_resource_opts *opts)
760 {
761 	struct spdk_nvmf_rdma_resources	*resources;
762 	struct spdk_nvmf_rdma_request	*rdma_req;
763 	struct spdk_nvmf_rdma_recv	*rdma_recv;
764 	struct ibv_qp			*qp;
765 	struct ibv_srq			*srq;
766 	uint32_t			i;
767 	int				rc;
768 
769 	resources = calloc(1, sizeof(struct spdk_nvmf_rdma_resources));
770 	if (!resources) {
771 		SPDK_ERRLOG("Unable to allocate resources for receive queue.\n");
772 		return NULL;
773 	}
774 
775 	resources->reqs = calloc(opts->max_queue_depth, sizeof(*resources->reqs));
776 	resources->recvs = calloc(opts->max_queue_depth, sizeof(*resources->recvs));
777 	resources->cmds = spdk_zmalloc(opts->max_queue_depth * sizeof(*resources->cmds),
778 				       0x1000, NULL, SPDK_ENV_LCORE_ID_ANY, SPDK_MALLOC_DMA);
779 	resources->cpls = spdk_zmalloc(opts->max_queue_depth * sizeof(*resources->cpls),
780 				       0x1000, NULL, SPDK_ENV_LCORE_ID_ANY, SPDK_MALLOC_DMA);
781 
782 	if (opts->in_capsule_data_size > 0) {
783 		resources->bufs = spdk_zmalloc(opts->max_queue_depth * opts->in_capsule_data_size,
784 					       0x1000, NULL, SPDK_ENV_LCORE_ID_ANY,
785 					       SPDK_MALLOC_DMA);
786 	}
787 
788 	if (!resources->reqs || !resources->recvs || !resources->cmds ||
789 	    !resources->cpls || (opts->in_capsule_data_size && !resources->bufs)) {
790 		SPDK_ERRLOG("Unable to allocate sufficient memory for RDMA queue.\n");
791 		goto cleanup;
792 	}
793 
794 	resources->cmds_mr = ibv_reg_mr(opts->pd, resources->cmds,
795 					opts->max_queue_depth * sizeof(*resources->cmds),
796 					IBV_ACCESS_LOCAL_WRITE);
797 	resources->cpls_mr = ibv_reg_mr(opts->pd, resources->cpls,
798 					opts->max_queue_depth * sizeof(*resources->cpls),
799 					0);
800 
801 	if (opts->in_capsule_data_size) {
802 		resources->bufs_mr = ibv_reg_mr(opts->pd, resources->bufs,
803 						opts->max_queue_depth *
804 						opts->in_capsule_data_size,
805 						IBV_ACCESS_LOCAL_WRITE | IBV_ACCESS_REMOTE_WRITE);
806 	}
807 
808 	if (!resources->cmds_mr || !resources->cpls_mr ||
809 	    (opts->in_capsule_data_size &&
810 	     !resources->bufs_mr)) {
811 		goto cleanup;
812 	}
813 	SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Command Array: %p Length: %lx LKey: %x\n",
814 		      resources->cmds, opts->max_queue_depth * sizeof(*resources->cmds),
815 		      resources->cmds_mr->lkey);
816 	SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Completion Array: %p Length: %lx LKey: %x\n",
817 		      resources->cpls, opts->max_queue_depth * sizeof(*resources->cpls),
818 		      resources->cpls_mr->lkey);
819 	if (resources->bufs && resources->bufs_mr) {
820 		SPDK_DEBUGLOG(SPDK_LOG_RDMA, "In Capsule Data Array: %p Length: %x LKey: %x\n",
821 			      resources->bufs, opts->max_queue_depth *
822 			      opts->in_capsule_data_size, resources->bufs_mr->lkey);
823 	}
824 
825 	/* Initialize queues */
826 	STAILQ_INIT(&resources->incoming_queue);
827 	STAILQ_INIT(&resources->free_queue);
828 
829 	for (i = 0; i < opts->max_queue_depth; i++) {
830 		struct ibv_recv_wr *bad_wr = NULL;
831 
832 		rdma_recv = &resources->recvs[i];
833 		rdma_recv->qpair = opts->qpair;
834 
835 		/* Set up memory to receive commands */
836 		if (resources->bufs) {
837 			rdma_recv->buf = (void *)((uintptr_t)resources->bufs + (i *
838 						  opts->in_capsule_data_size));
839 		}
840 
841 		rdma_recv->rdma_wr.type = RDMA_WR_TYPE_RECV;
842 
843 		rdma_recv->sgl[0].addr = (uintptr_t)&resources->cmds[i];
844 		rdma_recv->sgl[0].length = sizeof(resources->cmds[i]);
845 		rdma_recv->sgl[0].lkey = resources->cmds_mr->lkey;
846 		rdma_recv->wr.num_sge = 1;
847 
848 		if (rdma_recv->buf && resources->bufs_mr) {
849 			rdma_recv->sgl[1].addr = (uintptr_t)rdma_recv->buf;
850 			rdma_recv->sgl[1].length = opts->in_capsule_data_size;
851 			rdma_recv->sgl[1].lkey = resources->bufs_mr->lkey;
852 			rdma_recv->wr.num_sge++;
853 		}
854 
855 		rdma_recv->wr.wr_id = (uintptr_t)&rdma_recv->rdma_wr;
856 		rdma_recv->wr.sg_list = rdma_recv->sgl;
857 		if (opts->shared) {
858 			srq = (struct ibv_srq *)opts->qp;
859 			rc = ibv_post_srq_recv(srq, &rdma_recv->wr, &bad_wr);
860 		} else {
861 			qp = (struct ibv_qp *)opts->qp;
862 			rc = ibv_post_recv(qp, &rdma_recv->wr, &bad_wr);
863 		}
864 		if (rc) {
865 			goto cleanup;
866 		}
867 	}
868 
869 	for (i = 0; i < opts->max_queue_depth; i++) {
870 		rdma_req = &resources->reqs[i];
871 
872 		if (opts->qpair != NULL) {
873 			rdma_req->req.qpair = &opts->qpair->qpair;
874 		} else {
875 			rdma_req->req.qpair = NULL;
876 		}
877 		rdma_req->req.cmd = NULL;
878 
879 		/* Set up memory to send responses */
880 		rdma_req->req.rsp = &resources->cpls[i];
881 
882 		rdma_req->rsp.sgl[0].addr = (uintptr_t)&resources->cpls[i];
883 		rdma_req->rsp.sgl[0].length = sizeof(resources->cpls[i]);
884 		rdma_req->rsp.sgl[0].lkey = resources->cpls_mr->lkey;
885 
886 		rdma_req->rsp.rdma_wr.type = RDMA_WR_TYPE_SEND;
887 		rdma_req->rsp.wr.wr_id = (uintptr_t)&rdma_req->rsp.rdma_wr;
888 		rdma_req->rsp.wr.next = NULL;
889 		rdma_req->rsp.wr.opcode = IBV_WR_SEND;
890 		rdma_req->rsp.wr.send_flags = IBV_SEND_SIGNALED;
891 		rdma_req->rsp.wr.sg_list = rdma_req->rsp.sgl;
892 		rdma_req->rsp.wr.num_sge = SPDK_COUNTOF(rdma_req->rsp.sgl);
893 
894 		/* Set up memory for data buffers */
895 		rdma_req->data.rdma_wr.type = RDMA_WR_TYPE_DATA;
896 		rdma_req->data.wr.wr_id = (uintptr_t)&rdma_req->data.rdma_wr;
897 		rdma_req->data.wr.next = NULL;
898 		rdma_req->data.wr.send_flags = IBV_SEND_SIGNALED;
899 		rdma_req->data.wr.sg_list = rdma_req->data.sgl;
900 		rdma_req->data.wr.num_sge = SPDK_COUNTOF(rdma_req->data.sgl);
901 
902 		/* Initialize request state to FREE */
903 		rdma_req->state = RDMA_REQUEST_STATE_FREE;
904 		STAILQ_INSERT_TAIL(&resources->free_queue, rdma_req, state_link);
905 	}
906 
907 	return resources;
908 
909 cleanup:
910 	nvmf_rdma_resources_destroy(resources);
911 	return NULL;
912 }
913 
914 static void
915 spdk_nvmf_rdma_qpair_clean_ibv_events(struct spdk_nvmf_rdma_qpair *rqpair)
916 {
917 	struct spdk_nvmf_rdma_ibv_event_ctx *ctx, *tctx;
918 	STAILQ_FOREACH_SAFE(ctx, &rqpair->ibv_events, link, tctx) {
919 		ctx->rqpair = NULL;
920 		/* Memory allocated for ctx is freed in spdk_nvmf_rdma_qpair_process_ibv_event */
921 		STAILQ_REMOVE(&rqpair->ibv_events, ctx, spdk_nvmf_rdma_ibv_event_ctx, link);
922 	}
923 }
924 
925 static void
926 spdk_nvmf_rdma_qpair_destroy(struct spdk_nvmf_rdma_qpair *rqpair)
927 {
928 	struct spdk_nvmf_rdma_recv	*rdma_recv, *recv_tmp;
929 	struct ibv_recv_wr		*bad_recv_wr = NULL;
930 	int				rc;
931 
932 	spdk_trace_record(TRACE_RDMA_QP_DESTROY, 0, 0, (uintptr_t)rqpair->cm_id, 0);
933 
934 	spdk_poller_unregister(&rqpair->destruct_poller);
935 
936 	if (rqpair->qd != 0) {
937 		struct spdk_nvmf_qpair *qpair = &rqpair->qpair;
938 		struct spdk_nvmf_rdma_transport	*rtransport = SPDK_CONTAINEROF(qpair->transport,
939 				struct spdk_nvmf_rdma_transport, transport);
940 		struct spdk_nvmf_rdma_request *req;
941 		uint32_t i, max_req_count = 0;
942 
943 		SPDK_WARNLOG("Destroying qpair when queue depth is %d\n", rqpair->qd);
944 
945 		if (rqpair->srq == NULL) {
946 			nvmf_rdma_dump_qpair_contents(rqpair);
947 			max_req_count = rqpair->max_queue_depth;
948 		} else if (rqpair->poller && rqpair->resources) {
949 			max_req_count = rqpair->poller->max_srq_depth;
950 		}
951 
952 		SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Release incomplete requests\n");
953 		for (i = 0; i < max_req_count; i++) {
954 			req = &rqpair->resources->reqs[i];
955 			if (req->req.qpair == qpair && req->state != RDMA_REQUEST_STATE_FREE) {
956 				/* spdk_nvmf_rdma_request_process checks qpair ibv and internal state
957 				 * and completes a request */
958 				spdk_nvmf_rdma_request_process(rtransport, req);
959 			}
960 		}
961 		assert(rqpair->qd == 0);
962 	}
963 
964 	if (rqpair->poller) {
965 		TAILQ_REMOVE(&rqpair->poller->qpairs, rqpair, link);
966 
967 		if (rqpair->srq != NULL && rqpair->resources != NULL) {
968 			/* Drop all received but unprocessed commands for this queue and return them to SRQ */
969 			STAILQ_FOREACH_SAFE(rdma_recv, &rqpair->resources->incoming_queue, link, recv_tmp) {
970 				if (rqpair == rdma_recv->qpair) {
971 					STAILQ_REMOVE(&rqpair->resources->incoming_queue, rdma_recv, spdk_nvmf_rdma_recv, link);
972 					rc = ibv_post_srq_recv(rqpair->srq, &rdma_recv->wr, &bad_recv_wr);
973 					if (rc) {
974 						SPDK_ERRLOG("Unable to re-post rx descriptor\n");
975 					}
976 				}
977 			}
978 		}
979 	}
980 
981 	if (rqpair->cm_id) {
982 		if (rqpair->cm_id->qp != NULL) {
983 			rdma_destroy_qp(rqpair->cm_id);
984 		}
985 		rdma_destroy_id(rqpair->cm_id);
986 
987 		if (rqpair->poller != NULL && rqpair->srq == NULL) {
988 			rqpair->poller->required_num_wr -= MAX_WR_PER_QP(rqpair->max_queue_depth);
989 		}
990 	}
991 
992 	if (rqpair->srq == NULL && rqpair->resources != NULL) {
993 		nvmf_rdma_resources_destroy(rqpair->resources);
994 	}
995 
996 	spdk_nvmf_rdma_qpair_clean_ibv_events(rqpair);
997 
998 	free(rqpair);
999 }
1000 
1001 static int
1002 nvmf_rdma_resize_cq(struct spdk_nvmf_rdma_qpair *rqpair, struct spdk_nvmf_rdma_device *device)
1003 {
1004 	struct spdk_nvmf_rdma_poller	*rpoller;
1005 	int				rc, num_cqe, required_num_wr;
1006 
1007 	/* Enlarge CQ size dynamically */
1008 	rpoller = rqpair->poller;
1009 	required_num_wr = rpoller->required_num_wr + MAX_WR_PER_QP(rqpair->max_queue_depth);
1010 	num_cqe = rpoller->num_cqe;
1011 	if (num_cqe < required_num_wr) {
1012 		num_cqe = spdk_max(num_cqe * 2, required_num_wr);
1013 		num_cqe = spdk_min(num_cqe, device->attr.max_cqe);
1014 	}
1015 
1016 	if (rpoller->num_cqe != num_cqe) {
1017 		if (required_num_wr > device->attr.max_cqe) {
1018 			SPDK_ERRLOG("RDMA CQE requirement (%d) exceeds device max_cqe limitation (%d)\n",
1019 				    required_num_wr, device->attr.max_cqe);
1020 			return -1;
1021 		}
1022 
1023 		SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Resize RDMA CQ from %d to %d\n", rpoller->num_cqe, num_cqe);
1024 		rc = ibv_resize_cq(rpoller->cq, num_cqe);
1025 		if (rc) {
1026 			SPDK_ERRLOG("RDMA CQ resize failed: errno %d: %s\n", errno, spdk_strerror(errno));
1027 			return -1;
1028 		}
1029 
1030 		rpoller->num_cqe = num_cqe;
1031 	}
1032 
1033 	rpoller->required_num_wr = required_num_wr;
1034 	return 0;
1035 }
1036 
1037 static int
1038 spdk_nvmf_rdma_qpair_initialize(struct spdk_nvmf_qpair *qpair)
1039 {
1040 	struct spdk_nvmf_rdma_qpair		*rqpair;
1041 	int					rc;
1042 	struct spdk_nvmf_rdma_transport		*rtransport;
1043 	struct spdk_nvmf_transport		*transport;
1044 	struct spdk_nvmf_rdma_resource_opts	opts;
1045 	struct spdk_nvmf_rdma_device		*device;
1046 	struct ibv_qp_init_attr			ibv_init_attr;
1047 
1048 	rqpair = SPDK_CONTAINEROF(qpair, struct spdk_nvmf_rdma_qpair, qpair);
1049 	device = rqpair->device;
1050 
1051 	memset(&ibv_init_attr, 0, sizeof(struct ibv_qp_init_attr));
1052 	ibv_init_attr.qp_context	= rqpair;
1053 	ibv_init_attr.qp_type		= IBV_QPT_RC;
1054 	ibv_init_attr.send_cq		= rqpair->poller->cq;
1055 	ibv_init_attr.recv_cq		= rqpair->poller->cq;
1056 
1057 	if (rqpair->srq) {
1058 		ibv_init_attr.srq		= rqpair->srq;
1059 	} else {
1060 		ibv_init_attr.cap.max_recv_wr	= rqpair->max_queue_depth +
1061 						  1; /* RECV operations + dummy drain WR */
1062 	}
1063 
1064 	ibv_init_attr.cap.max_send_wr	= rqpair->max_queue_depth *
1065 					  2 + 1; /* SEND, READ, and WRITE operations + dummy drain WR */
1066 	ibv_init_attr.cap.max_send_sge	= spdk_min(device->attr.max_sge, NVMF_DEFAULT_TX_SGE);
1067 	ibv_init_attr.cap.max_recv_sge	= spdk_min(device->attr.max_sge, NVMF_DEFAULT_RX_SGE);
1068 
1069 	if (rqpair->srq == NULL && nvmf_rdma_resize_cq(rqpair, device) < 0) {
1070 		SPDK_ERRLOG("Failed to resize the completion queue. Cannot initialize qpair.\n");
1071 		goto error;
1072 	}
1073 
1074 	rc = rdma_create_qp(rqpair->cm_id, device->pd, &ibv_init_attr);
1075 	if (rc) {
1076 		SPDK_ERRLOG("rdma_create_qp failed: errno %d: %s\n", errno, spdk_strerror(errno));
1077 		goto error;
1078 	}
1079 
1080 	rqpair->max_send_depth = spdk_min((uint32_t)(rqpair->max_queue_depth * 2 + 1),
1081 					  ibv_init_attr.cap.max_send_wr);
1082 	rqpair->max_send_sge = spdk_min(NVMF_DEFAULT_TX_SGE, ibv_init_attr.cap.max_send_sge);
1083 	rqpair->max_recv_sge = spdk_min(NVMF_DEFAULT_RX_SGE, ibv_init_attr.cap.max_recv_sge);
1084 	spdk_trace_record(TRACE_RDMA_QP_CREATE, 0, 0, (uintptr_t)rqpair->cm_id, 0);
1085 	SPDK_DEBUGLOG(SPDK_LOG_RDMA, "New RDMA Connection: %p\n", qpair);
1086 
1087 	rqpair->sends_to_post.first = NULL;
1088 	rqpair->sends_to_post.last = NULL;
1089 
1090 	if (rqpair->poller->srq == NULL) {
1091 		rtransport = SPDK_CONTAINEROF(qpair->transport, struct spdk_nvmf_rdma_transport, transport);
1092 		transport = &rtransport->transport;
1093 
1094 		opts.qp = rqpair->cm_id->qp;
1095 		opts.pd = rqpair->cm_id->pd;
1096 		opts.qpair = rqpair;
1097 		opts.shared = false;
1098 		opts.max_queue_depth = rqpair->max_queue_depth;
1099 		opts.in_capsule_data_size = transport->opts.in_capsule_data_size;
1100 
1101 		rqpair->resources = nvmf_rdma_resources_create(&opts);
1102 
1103 		if (!rqpair->resources) {
1104 			SPDK_ERRLOG("Unable to allocate resources for receive queue.\n");
1105 			rdma_destroy_qp(rqpair->cm_id);
1106 			goto error;
1107 		}
1108 	} else {
1109 		rqpair->resources = rqpair->poller->resources;
1110 	}
1111 
1112 	rqpair->current_recv_depth = 0;
1113 	STAILQ_INIT(&rqpair->pending_rdma_read_queue);
1114 	STAILQ_INIT(&rqpair->pending_rdma_write_queue);
1115 
1116 	return 0;
1117 
1118 error:
1119 	rdma_destroy_id(rqpair->cm_id);
1120 	rqpair->cm_id = NULL;
1121 	return -1;
1122 }
1123 
1124 /* Append the given recv wr structure to the resource structs outstanding recvs list. */
1125 /* This function accepts either a single wr or the first wr in a linked list. */
1126 static void
1127 nvmf_rdma_qpair_queue_recv_wrs(struct spdk_nvmf_rdma_qpair *rqpair, struct ibv_recv_wr *first)
1128 {
1129 	struct ibv_recv_wr *last;
1130 
1131 	last = first;
1132 	while (last->next != NULL) {
1133 		last = last->next;
1134 	}
1135 
1136 	if (rqpair->resources->recvs_to_post.first == NULL) {
1137 		rqpair->resources->recvs_to_post.first = first;
1138 		rqpair->resources->recvs_to_post.last = last;
1139 		if (rqpair->srq == NULL) {
1140 			STAILQ_INSERT_TAIL(&rqpair->poller->qpairs_pending_recv, rqpair, recv_link);
1141 		}
1142 	} else {
1143 		rqpair->resources->recvs_to_post.last->next = first;
1144 		rqpair->resources->recvs_to_post.last = last;
1145 	}
1146 }
1147 
1148 /* Append the given send wr structure to the qpair's outstanding sends list. */
1149 /* This function accepts either a single wr or the first wr in a linked list. */
1150 static void
1151 nvmf_rdma_qpair_queue_send_wrs(struct spdk_nvmf_rdma_qpair *rqpair, struct ibv_send_wr *first)
1152 {
1153 	struct ibv_send_wr *last;
1154 
1155 	last = first;
1156 	while (last->next != NULL) {
1157 		last = last->next;
1158 	}
1159 
1160 	if (rqpair->sends_to_post.first == NULL) {
1161 		rqpair->sends_to_post.first = first;
1162 		rqpair->sends_to_post.last = last;
1163 		STAILQ_INSERT_TAIL(&rqpair->poller->qpairs_pending_send, rqpair, send_link);
1164 	} else {
1165 		rqpair->sends_to_post.last->next = first;
1166 		rqpair->sends_to_post.last = last;
1167 	}
1168 }
1169 
1170 static int
1171 request_transfer_in(struct spdk_nvmf_request *req)
1172 {
1173 	struct spdk_nvmf_rdma_request	*rdma_req;
1174 	struct spdk_nvmf_qpair		*qpair;
1175 	struct spdk_nvmf_rdma_qpair	*rqpair;
1176 
1177 	qpair = req->qpair;
1178 	rdma_req = SPDK_CONTAINEROF(req, struct spdk_nvmf_rdma_request, req);
1179 	rqpair = SPDK_CONTAINEROF(qpair, struct spdk_nvmf_rdma_qpair, qpair);
1180 
1181 	assert(req->xfer == SPDK_NVME_DATA_HOST_TO_CONTROLLER);
1182 	assert(rdma_req != NULL);
1183 
1184 	nvmf_rdma_qpair_queue_send_wrs(rqpair, &rdma_req->data.wr);
1185 	rqpair->current_read_depth += rdma_req->num_outstanding_data_wr;
1186 	rqpair->current_send_depth += rdma_req->num_outstanding_data_wr;
1187 	return 0;
1188 }
1189 
1190 static int
1191 request_transfer_out(struct spdk_nvmf_request *req, int *data_posted)
1192 {
1193 	int				num_outstanding_data_wr = 0;
1194 	struct spdk_nvmf_rdma_request	*rdma_req;
1195 	struct spdk_nvmf_qpair		*qpair;
1196 	struct spdk_nvmf_rdma_qpair	*rqpair;
1197 	struct spdk_nvme_cpl		*rsp;
1198 	struct ibv_send_wr		*first = NULL;
1199 
1200 	*data_posted = 0;
1201 	qpair = req->qpair;
1202 	rsp = &req->rsp->nvme_cpl;
1203 	rdma_req = SPDK_CONTAINEROF(req, struct spdk_nvmf_rdma_request, req);
1204 	rqpair = SPDK_CONTAINEROF(qpair, struct spdk_nvmf_rdma_qpair, qpair);
1205 
1206 	/* Advance our sq_head pointer */
1207 	if (qpair->sq_head == qpair->sq_head_max) {
1208 		qpair->sq_head = 0;
1209 	} else {
1210 		qpair->sq_head++;
1211 	}
1212 	rsp->sqhd = qpair->sq_head;
1213 
1214 	/* queue the capsule for the recv buffer */
1215 	assert(rdma_req->recv != NULL);
1216 
1217 	nvmf_rdma_qpair_queue_recv_wrs(rqpair, &rdma_req->recv->wr);
1218 
1219 	rdma_req->recv = NULL;
1220 	assert(rqpair->current_recv_depth > 0);
1221 	rqpair->current_recv_depth--;
1222 
1223 	/* Build the response which consists of optional
1224 	 * RDMA WRITEs to transfer data, plus an RDMA SEND
1225 	 * containing the response.
1226 	 */
1227 	first = &rdma_req->rsp.wr;
1228 
1229 	if (rsp->status.sc == SPDK_NVME_SC_SUCCESS &&
1230 	    req->xfer == SPDK_NVME_DATA_CONTROLLER_TO_HOST) {
1231 		first = &rdma_req->data.wr;
1232 		*data_posted = 1;
1233 		num_outstanding_data_wr = rdma_req->num_outstanding_data_wr;
1234 	}
1235 	nvmf_rdma_qpair_queue_send_wrs(rqpair, first);
1236 	/* +1 for the rsp wr */
1237 	rqpair->current_send_depth += num_outstanding_data_wr + 1;
1238 
1239 	return 0;
1240 }
1241 
1242 static int
1243 spdk_nvmf_rdma_event_accept(struct rdma_cm_id *id, struct spdk_nvmf_rdma_qpair *rqpair)
1244 {
1245 	struct spdk_nvmf_rdma_accept_private_data	accept_data;
1246 	struct rdma_conn_param				ctrlr_event_data = {};
1247 	int						rc;
1248 
1249 	accept_data.recfmt = 0;
1250 	accept_data.crqsize = rqpair->max_queue_depth;
1251 
1252 	ctrlr_event_data.private_data = &accept_data;
1253 	ctrlr_event_data.private_data_len = sizeof(accept_data);
1254 	if (id->ps == RDMA_PS_TCP) {
1255 		ctrlr_event_data.responder_resources = 0; /* We accept 0 reads from the host */
1256 		ctrlr_event_data.initiator_depth = rqpair->max_read_depth;
1257 	}
1258 
1259 	/* Configure infinite retries for the initiator side qpair.
1260 	 * When using a shared receive queue on the target side,
1261 	 * we need to pass this value to the initiator to prevent the
1262 	 * initiator side NIC from completing SEND requests back to the
1263 	 * initiator with status rnr_retry_count_exceeded. */
1264 	if (rqpair->srq != NULL) {
1265 		ctrlr_event_data.rnr_retry_count = 0x7;
1266 	}
1267 
1268 	rc = rdma_accept(id, &ctrlr_event_data);
1269 	if (rc) {
1270 		SPDK_ERRLOG("Error %d on rdma_accept\n", errno);
1271 	} else {
1272 		SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Sent back the accept\n");
1273 	}
1274 
1275 	return rc;
1276 }
1277 
1278 static void
1279 spdk_nvmf_rdma_event_reject(struct rdma_cm_id *id, enum spdk_nvmf_rdma_transport_error error)
1280 {
1281 	struct spdk_nvmf_rdma_reject_private_data	rej_data;
1282 
1283 	rej_data.recfmt = 0;
1284 	rej_data.sts = error;
1285 
1286 	rdma_reject(id, &rej_data, sizeof(rej_data));
1287 }
1288 
1289 static int
1290 nvmf_rdma_connect(struct spdk_nvmf_transport *transport, struct rdma_cm_event *event,
1291 		  new_qpair_fn cb_fn, void *cb_arg)
1292 {
1293 	struct spdk_nvmf_rdma_transport *rtransport;
1294 	struct spdk_nvmf_rdma_qpair	*rqpair = NULL;
1295 	struct spdk_nvmf_rdma_port	*port;
1296 	struct rdma_conn_param		*rdma_param = NULL;
1297 	const struct spdk_nvmf_rdma_request_private_data *private_data = NULL;
1298 	uint16_t			max_queue_depth;
1299 	uint16_t			max_read_depth;
1300 
1301 	rtransport = SPDK_CONTAINEROF(transport, struct spdk_nvmf_rdma_transport, transport);
1302 
1303 	assert(event->id != NULL); /* Impossible. Can't even reject the connection. */
1304 	assert(event->id->verbs != NULL); /* Impossible. No way to handle this. */
1305 
1306 	rdma_param = &event->param.conn;
1307 	if (rdma_param->private_data == NULL ||
1308 	    rdma_param->private_data_len < sizeof(struct spdk_nvmf_rdma_request_private_data)) {
1309 		SPDK_ERRLOG("connect request: no private data provided\n");
1310 		spdk_nvmf_rdma_event_reject(event->id, SPDK_NVMF_RDMA_ERROR_INVALID_PRIVATE_DATA_LENGTH);
1311 		return -1;
1312 	}
1313 
1314 	private_data = rdma_param->private_data;
1315 	if (private_data->recfmt != 0) {
1316 		SPDK_ERRLOG("Received RDMA private data with RECFMT != 0\n");
1317 		spdk_nvmf_rdma_event_reject(event->id, SPDK_NVMF_RDMA_ERROR_INVALID_RECFMT);
1318 		return -1;
1319 	}
1320 
1321 	SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Connect Recv on fabric intf name %s, dev_name %s\n",
1322 		      event->id->verbs->device->name, event->id->verbs->device->dev_name);
1323 
1324 	port = event->listen_id->context;
1325 	SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Listen Id was %p with verbs %p. ListenAddr: %p\n",
1326 		      event->listen_id, event->listen_id->verbs, port);
1327 
1328 	/* Figure out the supported queue depth. This is a multi-step process
1329 	 * that takes into account hardware maximums, host provided values,
1330 	 * and our target's internal memory limits */
1331 
1332 	SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Calculating Queue Depth\n");
1333 
1334 	/* Start with the maximum queue depth allowed by the target */
1335 	max_queue_depth = rtransport->transport.opts.max_queue_depth;
1336 	max_read_depth = rtransport->transport.opts.max_queue_depth;
1337 	SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Target Max Queue Depth: %d\n",
1338 		      rtransport->transport.opts.max_queue_depth);
1339 
1340 	/* Next check the local NIC's hardware limitations */
1341 	SPDK_DEBUGLOG(SPDK_LOG_RDMA,
1342 		      "Local NIC Max Send/Recv Queue Depth: %d Max Read/Write Queue Depth: %d\n",
1343 		      port->device->attr.max_qp_wr, port->device->attr.max_qp_rd_atom);
1344 	max_queue_depth = spdk_min(max_queue_depth, port->device->attr.max_qp_wr);
1345 	max_read_depth = spdk_min(max_read_depth, port->device->attr.max_qp_init_rd_atom);
1346 
1347 	/* Next check the remote NIC's hardware limitations */
1348 	SPDK_DEBUGLOG(SPDK_LOG_RDMA,
1349 		      "Host (Initiator) NIC Max Incoming RDMA R/W operations: %d Max Outgoing RDMA R/W operations: %d\n",
1350 		      rdma_param->initiator_depth, rdma_param->responder_resources);
1351 	if (rdma_param->initiator_depth > 0) {
1352 		max_read_depth = spdk_min(max_read_depth, rdma_param->initiator_depth);
1353 	}
1354 
1355 	/* Finally check for the host software requested values, which are
1356 	 * optional. */
1357 	if (rdma_param->private_data != NULL &&
1358 	    rdma_param->private_data_len >= sizeof(struct spdk_nvmf_rdma_request_private_data)) {
1359 		SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Host Receive Queue Size: %d\n", private_data->hrqsize);
1360 		SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Host Send Queue Size: %d\n", private_data->hsqsize);
1361 		max_queue_depth = spdk_min(max_queue_depth, private_data->hrqsize);
1362 		max_queue_depth = spdk_min(max_queue_depth, private_data->hsqsize + 1);
1363 	}
1364 
1365 	SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Final Negotiated Queue Depth: %d R/W Depth: %d\n",
1366 		      max_queue_depth, max_read_depth);
1367 
1368 	rqpair = calloc(1, sizeof(struct spdk_nvmf_rdma_qpair));
1369 	if (rqpair == NULL) {
1370 		SPDK_ERRLOG("Could not allocate new connection.\n");
1371 		spdk_nvmf_rdma_event_reject(event->id, SPDK_NVMF_RDMA_ERROR_NO_RESOURCES);
1372 		return -1;
1373 	}
1374 
1375 	rqpair->device = port->device;
1376 	rqpair->max_queue_depth = max_queue_depth;
1377 	rqpair->max_read_depth = max_read_depth;
1378 	rqpair->cm_id = event->id;
1379 	rqpair->listen_id = event->listen_id;
1380 	rqpair->qpair.transport = transport;
1381 	STAILQ_INIT(&rqpair->ibv_events);
1382 	/* use qid from the private data to determine the qpair type
1383 	   qid will be set to the appropriate value when the controller is created */
1384 	rqpair->qpair.qid = private_data->qid;
1385 
1386 	event->id->context = &rqpair->qpair;
1387 
1388 	cb_fn(&rqpair->qpair, cb_arg);
1389 
1390 	return 0;
1391 }
1392 
1393 static int
1394 spdk_nvmf_rdma_mem_notify(void *cb_ctx, struct spdk_mem_map *map,
1395 			  enum spdk_mem_map_notify_action action,
1396 			  void *vaddr, size_t size)
1397 {
1398 	struct ibv_pd *pd = cb_ctx;
1399 	struct ibv_mr *mr;
1400 	int rc;
1401 
1402 	switch (action) {
1403 	case SPDK_MEM_MAP_NOTIFY_REGISTER:
1404 		if (!g_nvmf_hooks.get_rkey) {
1405 			mr = ibv_reg_mr(pd, vaddr, size,
1406 					IBV_ACCESS_LOCAL_WRITE |
1407 					IBV_ACCESS_REMOTE_READ |
1408 					IBV_ACCESS_REMOTE_WRITE);
1409 			if (mr == NULL) {
1410 				SPDK_ERRLOG("ibv_reg_mr() failed\n");
1411 				return -1;
1412 			} else {
1413 				rc = spdk_mem_map_set_translation(map, (uint64_t)vaddr, size, (uint64_t)mr);
1414 			}
1415 		} else {
1416 			rc = spdk_mem_map_set_translation(map, (uint64_t)vaddr, size,
1417 							  g_nvmf_hooks.get_rkey(pd, vaddr, size));
1418 		}
1419 		break;
1420 	case SPDK_MEM_MAP_NOTIFY_UNREGISTER:
1421 		if (!g_nvmf_hooks.get_rkey) {
1422 			mr = (struct ibv_mr *)spdk_mem_map_translate(map, (uint64_t)vaddr, NULL);
1423 			if (mr) {
1424 				ibv_dereg_mr(mr);
1425 			}
1426 		}
1427 		rc = spdk_mem_map_clear_translation(map, (uint64_t)vaddr, size);
1428 		break;
1429 	default:
1430 		SPDK_UNREACHABLE();
1431 	}
1432 
1433 	return rc;
1434 }
1435 
1436 static int
1437 spdk_nvmf_rdma_check_contiguous_entries(uint64_t addr_1, uint64_t addr_2)
1438 {
1439 	/* Two contiguous mappings will point to the same address which is the start of the RDMA MR. */
1440 	return addr_1 == addr_2;
1441 }
1442 
1443 static inline void
1444 nvmf_rdma_setup_wr(struct ibv_send_wr *wr, struct ibv_send_wr *next,
1445 		   enum spdk_nvme_data_transfer xfer)
1446 {
1447 	if (xfer == SPDK_NVME_DATA_CONTROLLER_TO_HOST) {
1448 		wr->opcode = IBV_WR_RDMA_WRITE;
1449 		wr->send_flags = 0;
1450 		wr->next = next;
1451 	} else if (xfer == SPDK_NVME_DATA_HOST_TO_CONTROLLER) {
1452 		wr->opcode = IBV_WR_RDMA_READ;
1453 		wr->send_flags = IBV_SEND_SIGNALED;
1454 		wr->next = NULL;
1455 	} else {
1456 		assert(0);
1457 	}
1458 }
1459 
1460 static int
1461 nvmf_request_alloc_wrs(struct spdk_nvmf_rdma_transport *rtransport,
1462 		       struct spdk_nvmf_rdma_request *rdma_req,
1463 		       uint32_t num_sgl_descriptors)
1464 {
1465 	struct spdk_nvmf_rdma_request_data	*work_requests[SPDK_NVMF_MAX_SGL_ENTRIES];
1466 	struct spdk_nvmf_rdma_request_data	*current_data_wr;
1467 	uint32_t				i;
1468 
1469 	if (num_sgl_descriptors > SPDK_NVMF_MAX_SGL_ENTRIES) {
1470 		SPDK_ERRLOG("Requested too much entries (%u), the limit is %u\n",
1471 			    num_sgl_descriptors, SPDK_NVMF_MAX_SGL_ENTRIES);
1472 		return -EINVAL;
1473 	}
1474 
1475 	if (spdk_mempool_get_bulk(rtransport->data_wr_pool, (void **)work_requests, num_sgl_descriptors)) {
1476 		return -ENOMEM;
1477 	}
1478 
1479 	current_data_wr = &rdma_req->data;
1480 
1481 	for (i = 0; i < num_sgl_descriptors; i++) {
1482 		nvmf_rdma_setup_wr(&current_data_wr->wr, &work_requests[i]->wr, rdma_req->req.xfer);
1483 		current_data_wr->wr.next = &work_requests[i]->wr;
1484 		current_data_wr = work_requests[i];
1485 		current_data_wr->wr.sg_list = current_data_wr->sgl;
1486 		current_data_wr->wr.wr_id = rdma_req->data.wr.wr_id;
1487 	}
1488 
1489 	nvmf_rdma_setup_wr(&current_data_wr->wr, &rdma_req->rsp.wr, rdma_req->req.xfer);
1490 
1491 	return 0;
1492 }
1493 
1494 static inline void
1495 nvmf_rdma_setup_request(struct spdk_nvmf_rdma_request *rdma_req)
1496 {
1497 	struct ibv_send_wr		*wr = &rdma_req->data.wr;
1498 	struct spdk_nvme_sgl_descriptor	*sgl = &rdma_req->req.cmd->nvme_cmd.dptr.sgl1;
1499 
1500 	wr->wr.rdma.rkey = sgl->keyed.key;
1501 	wr->wr.rdma.remote_addr = sgl->address;
1502 	nvmf_rdma_setup_wr(wr, &rdma_req->rsp.wr, rdma_req->req.xfer);
1503 }
1504 
1505 static inline void
1506 nvmf_rdma_update_remote_addr(struct spdk_nvmf_rdma_request *rdma_req, uint32_t num_wrs)
1507 {
1508 	struct ibv_send_wr		*wr = &rdma_req->data.wr;
1509 	struct spdk_nvme_sgl_descriptor	*sgl = &rdma_req->req.cmd->nvme_cmd.dptr.sgl1;
1510 	uint32_t			i;
1511 	int				j;
1512 	uint64_t			remote_addr_offset = 0;
1513 
1514 	for (i = 0; i < num_wrs; ++i) {
1515 		wr->wr.rdma.rkey = sgl->keyed.key;
1516 		wr->wr.rdma.remote_addr = sgl->address + remote_addr_offset;
1517 		for (j = 0; j < wr->num_sge; ++j) {
1518 			remote_addr_offset += wr->sg_list[j].length;
1519 		}
1520 		wr = wr->next;
1521 	}
1522 }
1523 
1524 /* This function is used in the rare case that we have a buffer split over multiple memory regions. */
1525 static int
1526 nvmf_rdma_replace_buffer(struct spdk_nvmf_rdma_poll_group *rgroup, void **buf)
1527 {
1528 	struct spdk_nvmf_transport_poll_group	*group = &rgroup->group;
1529 	struct spdk_nvmf_transport		*transport = group->transport;
1530 	struct spdk_nvmf_transport_pg_cache_buf	*old_buf;
1531 	void					*new_buf;
1532 
1533 	if (!(STAILQ_EMPTY(&group->buf_cache))) {
1534 		group->buf_cache_count--;
1535 		new_buf = STAILQ_FIRST(&group->buf_cache);
1536 		STAILQ_REMOVE_HEAD(&group->buf_cache, link);
1537 		assert(*buf != NULL);
1538 	} else {
1539 		new_buf = spdk_mempool_get(transport->data_buf_pool);
1540 	}
1541 
1542 	if (*buf == NULL) {
1543 		return -ENOMEM;
1544 	}
1545 
1546 	old_buf = *buf;
1547 	STAILQ_INSERT_HEAD(&rgroup->retired_bufs, old_buf, link);
1548 	*buf = new_buf;
1549 	return 0;
1550 }
1551 
1552 static bool
1553 nvmf_rdma_get_lkey(struct spdk_nvmf_rdma_device *device, struct iovec *iov,
1554 		   uint32_t *_lkey)
1555 {
1556 	uint64_t	translation_len;
1557 	uint32_t	lkey;
1558 
1559 	translation_len = iov->iov_len;
1560 
1561 	if (!g_nvmf_hooks.get_rkey) {
1562 		lkey = ((struct ibv_mr *)spdk_mem_map_translate(device->map,
1563 				(uint64_t)iov->iov_base, &translation_len))->lkey;
1564 	} else {
1565 		lkey = spdk_mem_map_translate(device->map,
1566 					      (uint64_t)iov->iov_base, &translation_len);
1567 	}
1568 
1569 	if (spdk_unlikely(translation_len < iov->iov_len)) {
1570 		return false;
1571 	}
1572 
1573 	*_lkey = lkey;
1574 	return true;
1575 }
1576 
1577 static bool
1578 nvmf_rdma_fill_wr_sge(struct spdk_nvmf_rdma_device *device,
1579 		      struct iovec *iov, struct ibv_send_wr **_wr,
1580 		      uint32_t *_remaining_data_block, uint32_t *_offset,
1581 		      uint32_t *_num_extra_wrs,
1582 		      const struct spdk_dif_ctx *dif_ctx)
1583 {
1584 	struct ibv_send_wr *wr = *_wr;
1585 	struct ibv_sge	*sg_ele = &wr->sg_list[wr->num_sge];
1586 	uint32_t	lkey = 0;
1587 	uint32_t	remaining, data_block_size, md_size, sge_len;
1588 
1589 	if (spdk_unlikely(!nvmf_rdma_get_lkey(device, iov, &lkey))) {
1590 		/* This is a very rare case that can occur when using DPDK version < 19.05 */
1591 		SPDK_ERRLOG("Data buffer split over multiple RDMA Memory Regions. Removing it from circulation.\n");
1592 		return false;
1593 	}
1594 
1595 	if (spdk_likely(!dif_ctx)) {
1596 		sg_ele->lkey = lkey;
1597 		sg_ele->addr = (uintptr_t)(iov->iov_base);
1598 		sg_ele->length = iov->iov_len;
1599 		wr->num_sge++;
1600 	} else {
1601 		remaining = iov->iov_len - *_offset;
1602 		data_block_size = dif_ctx->block_size - dif_ctx->md_size;
1603 		md_size = dif_ctx->md_size;
1604 
1605 		while (remaining) {
1606 			if (wr->num_sge >= SPDK_NVMF_MAX_SGL_ENTRIES) {
1607 				if (*_num_extra_wrs > 0 && wr->next) {
1608 					*_wr = wr->next;
1609 					wr = *_wr;
1610 					wr->num_sge = 0;
1611 					sg_ele = &wr->sg_list[wr->num_sge];
1612 					(*_num_extra_wrs)--;
1613 				} else {
1614 					break;
1615 				}
1616 			}
1617 			sg_ele->lkey = lkey;
1618 			sg_ele->addr = (uintptr_t)((char *)iov->iov_base + *_offset);
1619 			sge_len = spdk_min(remaining, *_remaining_data_block);
1620 			sg_ele->length = sge_len;
1621 			remaining -= sge_len;
1622 			*_remaining_data_block -= sge_len;
1623 			*_offset += sge_len;
1624 
1625 			sg_ele++;
1626 			wr->num_sge++;
1627 
1628 			if (*_remaining_data_block == 0) {
1629 				/* skip metadata */
1630 				*_offset += md_size;
1631 				/* Metadata that do not fit this IO buffer will be included in the next IO buffer */
1632 				remaining -= spdk_min(remaining, md_size);
1633 				*_remaining_data_block = data_block_size;
1634 			}
1635 
1636 			if (remaining == 0) {
1637 				/* By subtracting the size of the last IOV from the offset, we ensure that we skip
1638 				   the remaining metadata bits at the beginning of the next buffer */
1639 				*_offset -= iov->iov_len;
1640 			}
1641 		}
1642 	}
1643 
1644 	return true;
1645 }
1646 
1647 static int
1648 nvmf_rdma_fill_wr_sgl(struct spdk_nvmf_rdma_poll_group *rgroup,
1649 		      struct spdk_nvmf_rdma_device *device,
1650 		      struct spdk_nvmf_rdma_request *rdma_req,
1651 		      struct ibv_send_wr *wr,
1652 		      uint32_t length,
1653 		      uint32_t num_extra_wrs)
1654 {
1655 	struct spdk_nvmf_request *req = &rdma_req->req;
1656 	struct spdk_dif_ctx *dif_ctx = NULL;
1657 	uint32_t remaining_data_block = 0;
1658 	uint32_t offset = 0;
1659 
1660 	if (spdk_unlikely(rdma_req->req.dif.dif_insert_or_strip)) {
1661 		dif_ctx = &rdma_req->req.dif.dif_ctx;
1662 		remaining_data_block = dif_ctx->block_size - dif_ctx->md_size;
1663 	}
1664 
1665 	wr->num_sge = 0;
1666 
1667 	while (length && (num_extra_wrs || wr->num_sge < SPDK_NVMF_MAX_SGL_ENTRIES)) {
1668 		while (spdk_unlikely(!nvmf_rdma_fill_wr_sge(device, &req->iov[rdma_req->iovpos], &wr,
1669 				     &remaining_data_block, &offset, &num_extra_wrs, dif_ctx))) {
1670 			if (nvmf_rdma_replace_buffer(rgroup, &req->buffers[rdma_req->iovpos]) == -ENOMEM) {
1671 				return -ENOMEM;
1672 			}
1673 			req->iov[rdma_req->iovpos].iov_base = (void *)((uintptr_t)(req->buffers[rdma_req->iovpos] +
1674 							      NVMF_DATA_BUFFER_MASK) &
1675 							      ~NVMF_DATA_BUFFER_MASK);
1676 		}
1677 
1678 		length -= req->iov[rdma_req->iovpos].iov_len;
1679 		rdma_req->iovpos++;
1680 	}
1681 
1682 	if (length) {
1683 		SPDK_ERRLOG("Not enough SG entries to hold data buffer\n");
1684 		return -EINVAL;
1685 	}
1686 
1687 	return 0;
1688 }
1689 
1690 static inline uint32_t
1691 nvmf_rdma_calc_num_wrs(uint32_t length, uint32_t io_unit_size, uint32_t block_size)
1692 {
1693 	/* estimate the number of SG entries and WRs needed to process the request */
1694 	uint32_t num_sge = 0;
1695 	uint32_t i;
1696 	uint32_t num_buffers = SPDK_CEIL_DIV(length, io_unit_size);
1697 
1698 	for (i = 0; i < num_buffers && length > 0; i++) {
1699 		uint32_t buffer_len = spdk_min(length, io_unit_size);
1700 		uint32_t num_sge_in_block = SPDK_CEIL_DIV(buffer_len, block_size);
1701 
1702 		if (num_sge_in_block * block_size > buffer_len) {
1703 			++num_sge_in_block;
1704 		}
1705 		num_sge += num_sge_in_block;
1706 		length -= buffer_len;
1707 	}
1708 	return SPDK_CEIL_DIV(num_sge, SPDK_NVMF_MAX_SGL_ENTRIES);
1709 }
1710 
1711 static int
1712 spdk_nvmf_rdma_request_fill_iovs(struct spdk_nvmf_rdma_transport *rtransport,
1713 				 struct spdk_nvmf_rdma_device *device,
1714 				 struct spdk_nvmf_rdma_request *rdma_req,
1715 				 uint32_t length)
1716 {
1717 	struct spdk_nvmf_rdma_qpair		*rqpair;
1718 	struct spdk_nvmf_rdma_poll_group	*rgroup;
1719 	struct spdk_nvmf_request		*req = &rdma_req->req;
1720 	struct ibv_send_wr			*wr = &rdma_req->data.wr;
1721 	int					rc;
1722 	uint32_t				num_wrs = 1;
1723 
1724 	rqpair = SPDK_CONTAINEROF(req->qpair, struct spdk_nvmf_rdma_qpair, qpair);
1725 	rgroup = rqpair->poller->group;
1726 
1727 	/* rdma wr specifics */
1728 	nvmf_rdma_setup_request(rdma_req);
1729 
1730 	rc = spdk_nvmf_request_get_buffers(req, &rgroup->group, &rtransport->transport,
1731 					   length);
1732 	if (rc != 0) {
1733 		return rc;
1734 	}
1735 
1736 	assert(req->iovcnt <= rqpair->max_send_sge);
1737 
1738 	rdma_req->iovpos = 0;
1739 
1740 	if (spdk_unlikely(req->dif.dif_insert_or_strip)) {
1741 		num_wrs = nvmf_rdma_calc_num_wrs(length, rtransport->transport.opts.io_unit_size,
1742 						 req->dif.dif_ctx.block_size);
1743 		if (num_wrs > 1) {
1744 			rc = nvmf_request_alloc_wrs(rtransport, rdma_req, num_wrs - 1);
1745 			if (rc != 0) {
1746 				goto err_exit;
1747 			}
1748 		}
1749 	}
1750 
1751 	rc = nvmf_rdma_fill_wr_sgl(rgroup, device, rdma_req, wr, length, num_wrs - 1);
1752 	if (spdk_unlikely(rc != 0)) {
1753 		goto err_exit;
1754 	}
1755 
1756 	if (spdk_unlikely(num_wrs > 1)) {
1757 		nvmf_rdma_update_remote_addr(rdma_req, num_wrs);
1758 	}
1759 
1760 	/* set the number of outstanding data WRs for this request. */
1761 	rdma_req->num_outstanding_data_wr = num_wrs;
1762 
1763 	return rc;
1764 
1765 err_exit:
1766 	spdk_nvmf_request_free_buffers(req, &rgroup->group, &rtransport->transport);
1767 	nvmf_rdma_request_free_data(rdma_req, rtransport);
1768 	req->iovcnt = 0;
1769 	return rc;
1770 }
1771 
1772 static int
1773 nvmf_rdma_request_fill_iovs_multi_sgl(struct spdk_nvmf_rdma_transport *rtransport,
1774 				      struct spdk_nvmf_rdma_device *device,
1775 				      struct spdk_nvmf_rdma_request *rdma_req)
1776 {
1777 	struct spdk_nvmf_rdma_qpair		*rqpair;
1778 	struct spdk_nvmf_rdma_poll_group	*rgroup;
1779 	struct ibv_send_wr			*current_wr;
1780 	struct spdk_nvmf_request		*req = &rdma_req->req;
1781 	struct spdk_nvme_sgl_descriptor		*inline_segment, *desc;
1782 	uint32_t				num_sgl_descriptors;
1783 	uint32_t				lengths[SPDK_NVMF_MAX_SGL_ENTRIES];
1784 	uint32_t				i;
1785 	int					rc;
1786 
1787 	rqpair = SPDK_CONTAINEROF(rdma_req->req.qpair, struct spdk_nvmf_rdma_qpair, qpair);
1788 	rgroup = rqpair->poller->group;
1789 
1790 	inline_segment = &req->cmd->nvme_cmd.dptr.sgl1;
1791 	assert(inline_segment->generic.type == SPDK_NVME_SGL_TYPE_LAST_SEGMENT);
1792 	assert(inline_segment->unkeyed.subtype == SPDK_NVME_SGL_SUBTYPE_OFFSET);
1793 
1794 	num_sgl_descriptors = inline_segment->unkeyed.length / sizeof(struct spdk_nvme_sgl_descriptor);
1795 	assert(num_sgl_descriptors <= SPDK_NVMF_MAX_SGL_ENTRIES);
1796 
1797 	if (nvmf_request_alloc_wrs(rtransport, rdma_req, num_sgl_descriptors - 1) != 0) {
1798 		return -ENOMEM;
1799 	}
1800 
1801 	desc = (struct spdk_nvme_sgl_descriptor *)rdma_req->recv->buf + inline_segment->address;
1802 	for (i = 0; i < num_sgl_descriptors; i++) {
1803 		if (spdk_likely(!req->dif.dif_insert_or_strip)) {
1804 			lengths[i] = desc->keyed.length;
1805 		} else {
1806 			req->dif.orig_length += desc->keyed.length;
1807 			lengths[i] = spdk_dif_get_length_with_md(desc->keyed.length, &req->dif.dif_ctx);
1808 			req->dif.elba_length += lengths[i];
1809 		}
1810 		desc++;
1811 	}
1812 
1813 	rc = spdk_nvmf_request_get_buffers_multi(req, &rgroup->group, &rtransport->transport,
1814 			lengths, num_sgl_descriptors);
1815 	if (rc != 0) {
1816 		nvmf_rdma_request_free_data(rdma_req, rtransport);
1817 		return rc;
1818 	}
1819 
1820 	/* The first WR must always be the embedded data WR. This is how we unwind them later. */
1821 	current_wr = &rdma_req->data.wr;
1822 	assert(current_wr != NULL);
1823 
1824 	req->length = 0;
1825 	rdma_req->iovpos = 0;
1826 	desc = (struct spdk_nvme_sgl_descriptor *)rdma_req->recv->buf + inline_segment->address;
1827 	for (i = 0; i < num_sgl_descriptors; i++) {
1828 		/* The descriptors must be keyed data block descriptors with an address, not an offset. */
1829 		if (spdk_unlikely(desc->generic.type != SPDK_NVME_SGL_TYPE_KEYED_DATA_BLOCK ||
1830 				  desc->keyed.subtype != SPDK_NVME_SGL_SUBTYPE_ADDRESS)) {
1831 			rc = -EINVAL;
1832 			goto err_exit;
1833 		}
1834 
1835 		current_wr->num_sge = 0;
1836 
1837 		rc = nvmf_rdma_fill_wr_sgl(rgroup, device, rdma_req, current_wr, lengths[i], 0);
1838 		if (rc != 0) {
1839 			rc = -ENOMEM;
1840 			goto err_exit;
1841 		}
1842 
1843 		req->length += desc->keyed.length;
1844 		current_wr->wr.rdma.rkey = desc->keyed.key;
1845 		current_wr->wr.rdma.remote_addr = desc->address;
1846 		current_wr = current_wr->next;
1847 		desc++;
1848 	}
1849 
1850 #ifdef SPDK_CONFIG_RDMA_SEND_WITH_INVAL
1851 	/* Go back to the last descriptor in the list. */
1852 	desc--;
1853 	if ((device->attr.device_cap_flags & IBV_DEVICE_MEM_MGT_EXTENSIONS) != 0) {
1854 		if (desc->keyed.subtype == SPDK_NVME_SGL_SUBTYPE_INVALIDATE_KEY) {
1855 			rdma_req->rsp.wr.opcode = IBV_WR_SEND_WITH_INV;
1856 			rdma_req->rsp.wr.imm_data = desc->keyed.key;
1857 		}
1858 	}
1859 #endif
1860 
1861 	rdma_req->num_outstanding_data_wr = num_sgl_descriptors;
1862 
1863 	return 0;
1864 
1865 err_exit:
1866 	spdk_nvmf_request_free_buffers(req, &rgroup->group, &rtransport->transport);
1867 	nvmf_rdma_request_free_data(rdma_req, rtransport);
1868 	return rc;
1869 }
1870 
1871 static int
1872 spdk_nvmf_rdma_request_parse_sgl(struct spdk_nvmf_rdma_transport *rtransport,
1873 				 struct spdk_nvmf_rdma_device *device,
1874 				 struct spdk_nvmf_rdma_request *rdma_req)
1875 {
1876 	struct spdk_nvmf_request		*req = &rdma_req->req;
1877 	struct spdk_nvme_cpl			*rsp;
1878 	struct spdk_nvme_sgl_descriptor		*sgl;
1879 	int					rc;
1880 	uint32_t				length;
1881 
1882 	rsp = &req->rsp->nvme_cpl;
1883 	sgl = &req->cmd->nvme_cmd.dptr.sgl1;
1884 
1885 	if (sgl->generic.type == SPDK_NVME_SGL_TYPE_KEYED_DATA_BLOCK &&
1886 	    (sgl->keyed.subtype == SPDK_NVME_SGL_SUBTYPE_ADDRESS ||
1887 	     sgl->keyed.subtype == SPDK_NVME_SGL_SUBTYPE_INVALIDATE_KEY)) {
1888 
1889 		length = sgl->keyed.length;
1890 		if (length > rtransport->transport.opts.max_io_size) {
1891 			SPDK_ERRLOG("SGL length 0x%x exceeds max io size 0x%x\n",
1892 				    length, rtransport->transport.opts.max_io_size);
1893 			rsp->status.sc = SPDK_NVME_SC_DATA_SGL_LENGTH_INVALID;
1894 			return -1;
1895 		}
1896 #ifdef SPDK_CONFIG_RDMA_SEND_WITH_INVAL
1897 		if ((device->attr.device_cap_flags & IBV_DEVICE_MEM_MGT_EXTENSIONS) != 0) {
1898 			if (sgl->keyed.subtype == SPDK_NVME_SGL_SUBTYPE_INVALIDATE_KEY) {
1899 				rdma_req->rsp.wr.opcode = IBV_WR_SEND_WITH_INV;
1900 				rdma_req->rsp.wr.imm_data = sgl->keyed.key;
1901 			}
1902 		}
1903 #endif
1904 
1905 		/* fill request length and populate iovs */
1906 		req->length = length;
1907 
1908 		if (spdk_unlikely(req->dif.dif_insert_or_strip)) {
1909 			req->dif.orig_length = length;
1910 			length = spdk_dif_get_length_with_md(length, &req->dif.dif_ctx);
1911 			req->dif.elba_length = length;
1912 		}
1913 
1914 		rc = spdk_nvmf_rdma_request_fill_iovs(rtransport, device, rdma_req, length);
1915 		if (spdk_unlikely(rc < 0)) {
1916 			if (rc == -EINVAL) {
1917 				SPDK_ERRLOG("SGL length exceeds the max I/O size\n");
1918 				rsp->status.sc = SPDK_NVME_SC_DATA_SGL_LENGTH_INVALID;
1919 				return -1;
1920 			}
1921 			/* No available buffers. Queue this request up. */
1922 			SPDK_DEBUGLOG(SPDK_LOG_RDMA, "No available large data buffers. Queueing request %p\n", rdma_req);
1923 			return 0;
1924 		}
1925 
1926 		/* backward compatible */
1927 		req->data = req->iov[0].iov_base;
1928 
1929 		SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Request %p took %d buffer/s from central pool\n", rdma_req,
1930 			      req->iovcnt);
1931 
1932 		return 0;
1933 	} else if (sgl->generic.type == SPDK_NVME_SGL_TYPE_DATA_BLOCK &&
1934 		   sgl->unkeyed.subtype == SPDK_NVME_SGL_SUBTYPE_OFFSET) {
1935 		uint64_t offset = sgl->address;
1936 		uint32_t max_len = rtransport->transport.opts.in_capsule_data_size;
1937 
1938 		SPDK_DEBUGLOG(SPDK_LOG_NVMF, "In-capsule data: offset 0x%" PRIx64 ", length 0x%x\n",
1939 			      offset, sgl->unkeyed.length);
1940 
1941 		if (offset > max_len) {
1942 			SPDK_ERRLOG("In-capsule offset 0x%" PRIx64 " exceeds capsule length 0x%x\n",
1943 				    offset, max_len);
1944 			rsp->status.sc = SPDK_NVME_SC_INVALID_SGL_OFFSET;
1945 			return -1;
1946 		}
1947 		max_len -= (uint32_t)offset;
1948 
1949 		if (sgl->unkeyed.length > max_len) {
1950 			SPDK_ERRLOG("In-capsule data length 0x%x exceeds capsule length 0x%x\n",
1951 				    sgl->unkeyed.length, max_len);
1952 			rsp->status.sc = SPDK_NVME_SC_DATA_SGL_LENGTH_INVALID;
1953 			return -1;
1954 		}
1955 
1956 		rdma_req->num_outstanding_data_wr = 0;
1957 		req->data = rdma_req->recv->buf + offset;
1958 		req->data_from_pool = false;
1959 		req->length = sgl->unkeyed.length;
1960 
1961 		req->iov[0].iov_base = req->data;
1962 		req->iov[0].iov_len = req->length;
1963 		req->iovcnt = 1;
1964 
1965 		return 0;
1966 	} else if (sgl->generic.type == SPDK_NVME_SGL_TYPE_LAST_SEGMENT &&
1967 		   sgl->unkeyed.subtype == SPDK_NVME_SGL_SUBTYPE_OFFSET) {
1968 
1969 		rc = nvmf_rdma_request_fill_iovs_multi_sgl(rtransport, device, rdma_req);
1970 		if (rc == -ENOMEM) {
1971 			SPDK_DEBUGLOG(SPDK_LOG_RDMA, "No available large data buffers. Queueing request %p\n", rdma_req);
1972 			return 0;
1973 		} else if (rc == -EINVAL) {
1974 			SPDK_ERRLOG("Multi SGL element request length exceeds the max I/O size\n");
1975 			rsp->status.sc = SPDK_NVME_SC_DATA_SGL_LENGTH_INVALID;
1976 			return -1;
1977 		}
1978 
1979 		/* backward compatible */
1980 		req->data = req->iov[0].iov_base;
1981 
1982 		SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Request %p took %d buffer/s from central pool\n", rdma_req,
1983 			      req->iovcnt);
1984 
1985 		return 0;
1986 	}
1987 
1988 	SPDK_ERRLOG("Invalid NVMf I/O Command SGL:  Type 0x%x, Subtype 0x%x\n",
1989 		    sgl->generic.type, sgl->generic.subtype);
1990 	rsp->status.sc = SPDK_NVME_SC_SGL_DESCRIPTOR_TYPE_INVALID;
1991 	return -1;
1992 }
1993 
1994 static void
1995 nvmf_rdma_request_free(struct spdk_nvmf_rdma_request *rdma_req,
1996 		       struct spdk_nvmf_rdma_transport	*rtransport)
1997 {
1998 	struct spdk_nvmf_rdma_qpair		*rqpair;
1999 	struct spdk_nvmf_rdma_poll_group	*rgroup;
2000 
2001 	rqpair = SPDK_CONTAINEROF(rdma_req->req.qpair, struct spdk_nvmf_rdma_qpair, qpair);
2002 	if (rdma_req->req.data_from_pool) {
2003 		rgroup = rqpair->poller->group;
2004 
2005 		spdk_nvmf_request_free_buffers(&rdma_req->req, &rgroup->group, &rtransport->transport);
2006 	}
2007 	nvmf_rdma_request_free_data(rdma_req, rtransport);
2008 	rdma_req->req.length = 0;
2009 	rdma_req->req.iovcnt = 0;
2010 	rdma_req->req.data = NULL;
2011 	rdma_req->rsp.wr.next = NULL;
2012 	rdma_req->data.wr.next = NULL;
2013 	memset(&rdma_req->req.dif, 0, sizeof(rdma_req->req.dif));
2014 	rqpair->qd--;
2015 
2016 	STAILQ_INSERT_HEAD(&rqpair->resources->free_queue, rdma_req, state_link);
2017 	rdma_req->state = RDMA_REQUEST_STATE_FREE;
2018 }
2019 
2020 bool
2021 spdk_nvmf_rdma_request_process(struct spdk_nvmf_rdma_transport *rtransport,
2022 			       struct spdk_nvmf_rdma_request *rdma_req)
2023 {
2024 	struct spdk_nvmf_rdma_qpair	*rqpair;
2025 	struct spdk_nvmf_rdma_device	*device;
2026 	struct spdk_nvmf_rdma_poll_group *rgroup;
2027 	struct spdk_nvme_cpl		*rsp = &rdma_req->req.rsp->nvme_cpl;
2028 	int				rc;
2029 	struct spdk_nvmf_rdma_recv	*rdma_recv;
2030 	enum spdk_nvmf_rdma_request_state prev_state;
2031 	bool				progress = false;
2032 	int				data_posted;
2033 	uint32_t			num_blocks;
2034 
2035 	rqpair = SPDK_CONTAINEROF(rdma_req->req.qpair, struct spdk_nvmf_rdma_qpair, qpair);
2036 	device = rqpair->device;
2037 	rgroup = rqpair->poller->group;
2038 
2039 	assert(rdma_req->state != RDMA_REQUEST_STATE_FREE);
2040 
2041 	/* If the queue pair is in an error state, force the request to the completed state
2042 	 * to release resources. */
2043 	if (rqpair->ibv_state == IBV_QPS_ERR || rqpair->qpair.state != SPDK_NVMF_QPAIR_ACTIVE) {
2044 		if (rdma_req->state == RDMA_REQUEST_STATE_NEED_BUFFER) {
2045 			STAILQ_REMOVE(&rgroup->group.pending_buf_queue, &rdma_req->req, spdk_nvmf_request, buf_link);
2046 		} else if (rdma_req->state == RDMA_REQUEST_STATE_DATA_TRANSFER_TO_CONTROLLER_PENDING) {
2047 			STAILQ_REMOVE(&rqpair->pending_rdma_read_queue, rdma_req, spdk_nvmf_rdma_request, state_link);
2048 		} else if (rdma_req->state == RDMA_REQUEST_STATE_DATA_TRANSFER_TO_HOST_PENDING) {
2049 			STAILQ_REMOVE(&rqpair->pending_rdma_write_queue, rdma_req, spdk_nvmf_rdma_request, state_link);
2050 		}
2051 		rdma_req->state = RDMA_REQUEST_STATE_COMPLETED;
2052 	}
2053 
2054 	/* The loop here is to allow for several back-to-back state changes. */
2055 	do {
2056 		prev_state = rdma_req->state;
2057 
2058 		SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Request %p entering state %d\n", rdma_req, prev_state);
2059 
2060 		switch (rdma_req->state) {
2061 		case RDMA_REQUEST_STATE_FREE:
2062 			/* Some external code must kick a request into RDMA_REQUEST_STATE_NEW
2063 			 * to escape this state. */
2064 			break;
2065 		case RDMA_REQUEST_STATE_NEW:
2066 			spdk_trace_record(TRACE_RDMA_REQUEST_STATE_NEW, 0, 0,
2067 					  (uintptr_t)rdma_req, (uintptr_t)rqpair->cm_id);
2068 			rdma_recv = rdma_req->recv;
2069 
2070 			/* The first element of the SGL is the NVMe command */
2071 			rdma_req->req.cmd = (union nvmf_h2c_msg *)rdma_recv->sgl[0].addr;
2072 			memset(rdma_req->req.rsp, 0, sizeof(*rdma_req->req.rsp));
2073 
2074 			if (rqpair->ibv_state == IBV_QPS_ERR  || rqpair->qpair.state != SPDK_NVMF_QPAIR_ACTIVE) {
2075 				rdma_req->state = RDMA_REQUEST_STATE_COMPLETED;
2076 				break;
2077 			}
2078 
2079 			if (spdk_unlikely(spdk_nvmf_request_get_dif_ctx(&rdma_req->req, &rdma_req->req.dif.dif_ctx))) {
2080 				rdma_req->req.dif.dif_insert_or_strip = true;
2081 			}
2082 
2083 #ifdef SPDK_CONFIG_RDMA_SEND_WITH_INVAL
2084 			rdma_req->rsp.wr.opcode = IBV_WR_SEND;
2085 			rdma_req->rsp.wr.imm_data = 0;
2086 #endif
2087 
2088 			/* The next state transition depends on the data transfer needs of this request. */
2089 			rdma_req->req.xfer = spdk_nvmf_req_get_xfer(&rdma_req->req);
2090 
2091 			/* If no data to transfer, ready to execute. */
2092 			if (rdma_req->req.xfer == SPDK_NVME_DATA_NONE) {
2093 				rdma_req->state = RDMA_REQUEST_STATE_READY_TO_EXECUTE;
2094 				break;
2095 			}
2096 
2097 			rdma_req->state = RDMA_REQUEST_STATE_NEED_BUFFER;
2098 			STAILQ_INSERT_TAIL(&rgroup->group.pending_buf_queue, &rdma_req->req, buf_link);
2099 			break;
2100 		case RDMA_REQUEST_STATE_NEED_BUFFER:
2101 			spdk_trace_record(TRACE_RDMA_REQUEST_STATE_NEED_BUFFER, 0, 0,
2102 					  (uintptr_t)rdma_req, (uintptr_t)rqpair->cm_id);
2103 
2104 			assert(rdma_req->req.xfer != SPDK_NVME_DATA_NONE);
2105 
2106 			if (&rdma_req->req != STAILQ_FIRST(&rgroup->group.pending_buf_queue)) {
2107 				/* This request needs to wait in line to obtain a buffer */
2108 				break;
2109 			}
2110 
2111 			/* Try to get a data buffer */
2112 			rc = spdk_nvmf_rdma_request_parse_sgl(rtransport, device, rdma_req);
2113 			if (rc < 0) {
2114 				STAILQ_REMOVE_HEAD(&rgroup->group.pending_buf_queue, buf_link);
2115 				rdma_req->state = RDMA_REQUEST_STATE_READY_TO_COMPLETE;
2116 				break;
2117 			}
2118 
2119 			if (!rdma_req->req.data) {
2120 				/* No buffers available. */
2121 				rgroup->stat.pending_data_buffer++;
2122 				break;
2123 			}
2124 
2125 			STAILQ_REMOVE_HEAD(&rgroup->group.pending_buf_queue, buf_link);
2126 
2127 			/* If data is transferring from host to controller and the data didn't
2128 			 * arrive using in capsule data, we need to do a transfer from the host.
2129 			 */
2130 			if (rdma_req->req.xfer == SPDK_NVME_DATA_HOST_TO_CONTROLLER &&
2131 			    rdma_req->req.data_from_pool) {
2132 				STAILQ_INSERT_TAIL(&rqpair->pending_rdma_read_queue, rdma_req, state_link);
2133 				rdma_req->state = RDMA_REQUEST_STATE_DATA_TRANSFER_TO_CONTROLLER_PENDING;
2134 				break;
2135 			}
2136 
2137 			rdma_req->state = RDMA_REQUEST_STATE_READY_TO_EXECUTE;
2138 			break;
2139 		case RDMA_REQUEST_STATE_DATA_TRANSFER_TO_CONTROLLER_PENDING:
2140 			spdk_trace_record(TRACE_RDMA_REQUEST_STATE_DATA_TRANSFER_TO_CONTROLLER_PENDING, 0, 0,
2141 					  (uintptr_t)rdma_req, (uintptr_t)rqpair->cm_id);
2142 
2143 			if (rdma_req != STAILQ_FIRST(&rqpair->pending_rdma_read_queue)) {
2144 				/* This request needs to wait in line to perform RDMA */
2145 				break;
2146 			}
2147 			if (rqpair->current_send_depth + rdma_req->num_outstanding_data_wr > rqpair->max_send_depth
2148 			    || rqpair->current_read_depth + rdma_req->num_outstanding_data_wr > rqpair->max_read_depth) {
2149 				/* We can only have so many WRs outstanding. we have to wait until some finish. */
2150 				rqpair->poller->stat.pending_rdma_read++;
2151 				break;
2152 			}
2153 
2154 			/* We have already verified that this request is the head of the queue. */
2155 			STAILQ_REMOVE_HEAD(&rqpair->pending_rdma_read_queue, state_link);
2156 
2157 			rc = request_transfer_in(&rdma_req->req);
2158 			if (!rc) {
2159 				rdma_req->state = RDMA_REQUEST_STATE_TRANSFERRING_HOST_TO_CONTROLLER;
2160 			} else {
2161 				rsp->status.sc = SPDK_NVME_SC_INTERNAL_DEVICE_ERROR;
2162 				rdma_req->state = RDMA_REQUEST_STATE_READY_TO_COMPLETE;
2163 			}
2164 			break;
2165 		case RDMA_REQUEST_STATE_TRANSFERRING_HOST_TO_CONTROLLER:
2166 			spdk_trace_record(TRACE_RDMA_REQUEST_STATE_TRANSFERRING_HOST_TO_CONTROLLER, 0, 0,
2167 					  (uintptr_t)rdma_req, (uintptr_t)rqpair->cm_id);
2168 			/* Some external code must kick a request into RDMA_REQUEST_STATE_READY_TO_EXECUTE
2169 			 * to escape this state. */
2170 			break;
2171 		case RDMA_REQUEST_STATE_READY_TO_EXECUTE:
2172 			spdk_trace_record(TRACE_RDMA_REQUEST_STATE_READY_TO_EXECUTE, 0, 0,
2173 					  (uintptr_t)rdma_req, (uintptr_t)rqpair->cm_id);
2174 
2175 			if (spdk_unlikely(rdma_req->req.dif.dif_insert_or_strip)) {
2176 				if (rdma_req->req.xfer == SPDK_NVME_DATA_HOST_TO_CONTROLLER) {
2177 					/* generate DIF for write operation */
2178 					num_blocks = SPDK_CEIL_DIV(rdma_req->req.dif.elba_length, rdma_req->req.dif.dif_ctx.block_size);
2179 					assert(num_blocks > 0);
2180 
2181 					rc = spdk_dif_generate(rdma_req->req.iov, rdma_req->req.iovcnt,
2182 							       num_blocks, &rdma_req->req.dif.dif_ctx);
2183 					if (rc != 0) {
2184 						SPDK_ERRLOG("DIF generation failed\n");
2185 						rdma_req->state = RDMA_REQUEST_STATE_COMPLETED;
2186 						spdk_nvmf_rdma_start_disconnect(rqpair);
2187 						break;
2188 					}
2189 				}
2190 
2191 				assert(rdma_req->req.dif.elba_length >= rdma_req->req.length);
2192 				/* set extended length before IO operation */
2193 				rdma_req->req.length = rdma_req->req.dif.elba_length;
2194 			}
2195 
2196 			rdma_req->state = RDMA_REQUEST_STATE_EXECUTING;
2197 			spdk_nvmf_request_exec(&rdma_req->req);
2198 			break;
2199 		case RDMA_REQUEST_STATE_EXECUTING:
2200 			spdk_trace_record(TRACE_RDMA_REQUEST_STATE_EXECUTING, 0, 0,
2201 					  (uintptr_t)rdma_req, (uintptr_t)rqpair->cm_id);
2202 			/* Some external code must kick a request into RDMA_REQUEST_STATE_EXECUTED
2203 			 * to escape this state. */
2204 			break;
2205 		case RDMA_REQUEST_STATE_EXECUTED:
2206 			spdk_trace_record(TRACE_RDMA_REQUEST_STATE_EXECUTED, 0, 0,
2207 					  (uintptr_t)rdma_req, (uintptr_t)rqpair->cm_id);
2208 			if (rdma_req->req.xfer == SPDK_NVME_DATA_CONTROLLER_TO_HOST) {
2209 				STAILQ_INSERT_TAIL(&rqpair->pending_rdma_write_queue, rdma_req, state_link);
2210 				rdma_req->state = RDMA_REQUEST_STATE_DATA_TRANSFER_TO_HOST_PENDING;
2211 			} else {
2212 				rdma_req->state = RDMA_REQUEST_STATE_READY_TO_COMPLETE;
2213 			}
2214 			if (spdk_unlikely(rdma_req->req.dif.dif_insert_or_strip)) {
2215 				/* restore the original length */
2216 				rdma_req->req.length = rdma_req->req.dif.orig_length;
2217 
2218 				if (rdma_req->req.xfer == SPDK_NVME_DATA_CONTROLLER_TO_HOST) {
2219 					struct spdk_dif_error error_blk;
2220 
2221 					num_blocks = SPDK_CEIL_DIV(rdma_req->req.dif.elba_length, rdma_req->req.dif.dif_ctx.block_size);
2222 
2223 					rc = spdk_dif_verify(rdma_req->req.iov, rdma_req->req.iovcnt, num_blocks,
2224 							     &rdma_req->req.dif.dif_ctx, &error_blk);
2225 					if (rc) {
2226 						struct spdk_nvme_cpl *rsp = &rdma_req->req.rsp->nvme_cpl;
2227 
2228 						SPDK_ERRLOG("DIF error detected. type=%d, offset=%" PRIu32 "\n", error_blk.err_type,
2229 							    error_blk.err_offset);
2230 						rsp->status.sct = SPDK_NVME_SCT_MEDIA_ERROR;
2231 						rsp->status.sc = spdk_nvmf_rdma_dif_error_to_compl_status(error_blk.err_type);
2232 						rdma_req->state = RDMA_REQUEST_STATE_READY_TO_COMPLETE;
2233 						STAILQ_REMOVE(&rqpair->pending_rdma_write_queue, rdma_req, spdk_nvmf_rdma_request, state_link);
2234 					}
2235 				}
2236 			}
2237 			break;
2238 		case RDMA_REQUEST_STATE_DATA_TRANSFER_TO_HOST_PENDING:
2239 			spdk_trace_record(TRACE_RDMA_REQUEST_STATE_DATA_TRANSFER_TO_HOST_PENDING, 0, 0,
2240 					  (uintptr_t)rdma_req, (uintptr_t)rqpair->cm_id);
2241 
2242 			if (rdma_req != STAILQ_FIRST(&rqpair->pending_rdma_write_queue)) {
2243 				/* This request needs to wait in line to perform RDMA */
2244 				break;
2245 			}
2246 			if ((rqpair->current_send_depth + rdma_req->num_outstanding_data_wr + 1) >
2247 			    rqpair->max_send_depth) {
2248 				/* We can only have so many WRs outstanding. we have to wait until some finish.
2249 				 * +1 since each request has an additional wr in the resp. */
2250 				rqpair->poller->stat.pending_rdma_write++;
2251 				break;
2252 			}
2253 
2254 			/* We have already verified that this request is the head of the queue. */
2255 			STAILQ_REMOVE_HEAD(&rqpair->pending_rdma_write_queue, state_link);
2256 
2257 			/* The data transfer will be kicked off from
2258 			 * RDMA_REQUEST_STATE_READY_TO_COMPLETE state.
2259 			 */
2260 			rdma_req->state = RDMA_REQUEST_STATE_READY_TO_COMPLETE;
2261 			break;
2262 		case RDMA_REQUEST_STATE_READY_TO_COMPLETE:
2263 			spdk_trace_record(TRACE_RDMA_REQUEST_STATE_READY_TO_COMPLETE, 0, 0,
2264 					  (uintptr_t)rdma_req, (uintptr_t)rqpair->cm_id);
2265 			rc = request_transfer_out(&rdma_req->req, &data_posted);
2266 			assert(rc == 0); /* No good way to handle this currently */
2267 			if (rc) {
2268 				rdma_req->state = RDMA_REQUEST_STATE_COMPLETED;
2269 			} else {
2270 				rdma_req->state = data_posted ? RDMA_REQUEST_STATE_TRANSFERRING_CONTROLLER_TO_HOST :
2271 						  RDMA_REQUEST_STATE_COMPLETING;
2272 			}
2273 			break;
2274 		case RDMA_REQUEST_STATE_TRANSFERRING_CONTROLLER_TO_HOST:
2275 			spdk_trace_record(TRACE_RDMA_REQUEST_STATE_TRANSFERRING_CONTROLLER_TO_HOST, 0, 0,
2276 					  (uintptr_t)rdma_req, (uintptr_t)rqpair->cm_id);
2277 			/* Some external code must kick a request into RDMA_REQUEST_STATE_COMPLETED
2278 			 * to escape this state. */
2279 			break;
2280 		case RDMA_REQUEST_STATE_COMPLETING:
2281 			spdk_trace_record(TRACE_RDMA_REQUEST_STATE_COMPLETING, 0, 0,
2282 					  (uintptr_t)rdma_req, (uintptr_t)rqpair->cm_id);
2283 			/* Some external code must kick a request into RDMA_REQUEST_STATE_COMPLETED
2284 			 * to escape this state. */
2285 			break;
2286 		case RDMA_REQUEST_STATE_COMPLETED:
2287 			spdk_trace_record(TRACE_RDMA_REQUEST_STATE_COMPLETED, 0, 0,
2288 					  (uintptr_t)rdma_req, (uintptr_t)rqpair->cm_id);
2289 
2290 			rqpair->poller->stat.request_latency += spdk_get_ticks() - rdma_req->receive_tsc;
2291 			nvmf_rdma_request_free(rdma_req, rtransport);
2292 			break;
2293 		case RDMA_REQUEST_NUM_STATES:
2294 		default:
2295 			assert(0);
2296 			break;
2297 		}
2298 
2299 		if (rdma_req->state != prev_state) {
2300 			progress = true;
2301 		}
2302 	} while (rdma_req->state != prev_state);
2303 
2304 	return progress;
2305 }
2306 
2307 /* Public API callbacks begin here */
2308 
2309 #define SPDK_NVMF_RDMA_DEFAULT_MAX_QUEUE_DEPTH 128
2310 #define SPDK_NVMF_RDMA_DEFAULT_AQ_DEPTH 128
2311 #define SPDK_NVMF_RDMA_DEFAULT_SRQ_DEPTH 4096
2312 #define SPDK_NVMF_RDMA_DEFAULT_MAX_QPAIRS_PER_CTRLR 128
2313 #define SPDK_NVMF_RDMA_DEFAULT_IN_CAPSULE_DATA_SIZE 4096
2314 #define SPDK_NVMF_RDMA_DEFAULT_MAX_IO_SIZE 131072
2315 #define SPDK_NVMF_RDMA_MIN_IO_BUFFER_SIZE (SPDK_NVMF_RDMA_DEFAULT_MAX_IO_SIZE / SPDK_NVMF_MAX_SGL_ENTRIES)
2316 #define SPDK_NVMF_RDMA_DEFAULT_NUM_SHARED_BUFFERS 4095
2317 #define SPDK_NVMF_RDMA_DEFAULT_BUFFER_CACHE_SIZE 32
2318 #define SPDK_NVMF_RDMA_DEFAULT_NO_SRQ false
2319 #define SPDK_NVMF_RDMA_DIF_INSERT_OR_STRIP false
2320 
2321 static void
2322 spdk_nvmf_rdma_opts_init(struct spdk_nvmf_transport_opts *opts)
2323 {
2324 	opts->max_queue_depth =		SPDK_NVMF_RDMA_DEFAULT_MAX_QUEUE_DEPTH;
2325 	opts->max_qpairs_per_ctrlr =	SPDK_NVMF_RDMA_DEFAULT_MAX_QPAIRS_PER_CTRLR;
2326 	opts->in_capsule_data_size =	SPDK_NVMF_RDMA_DEFAULT_IN_CAPSULE_DATA_SIZE;
2327 	opts->max_io_size =		SPDK_NVMF_RDMA_DEFAULT_MAX_IO_SIZE;
2328 	opts->io_unit_size =		SPDK_NVMF_RDMA_MIN_IO_BUFFER_SIZE;
2329 	opts->max_aq_depth =		SPDK_NVMF_RDMA_DEFAULT_AQ_DEPTH;
2330 	opts->num_shared_buffers =	SPDK_NVMF_RDMA_DEFAULT_NUM_SHARED_BUFFERS;
2331 	opts->buf_cache_size =		SPDK_NVMF_RDMA_DEFAULT_BUFFER_CACHE_SIZE;
2332 	opts->max_srq_depth =		SPDK_NVMF_RDMA_DEFAULT_SRQ_DEPTH;
2333 	opts->no_srq =			SPDK_NVMF_RDMA_DEFAULT_NO_SRQ;
2334 	opts->dif_insert_or_strip =	SPDK_NVMF_RDMA_DIF_INSERT_OR_STRIP;
2335 }
2336 
2337 const struct spdk_mem_map_ops g_nvmf_rdma_map_ops = {
2338 	.notify_cb = spdk_nvmf_rdma_mem_notify,
2339 	.are_contiguous = spdk_nvmf_rdma_check_contiguous_entries
2340 };
2341 
2342 static int spdk_nvmf_rdma_destroy(struct spdk_nvmf_transport *transport);
2343 
2344 static struct spdk_nvmf_transport *
2345 spdk_nvmf_rdma_create(struct spdk_nvmf_transport_opts *opts)
2346 {
2347 	int rc;
2348 	struct spdk_nvmf_rdma_transport *rtransport;
2349 	struct spdk_nvmf_rdma_device	*device, *tmp;
2350 	struct ibv_context		**contexts;
2351 	uint32_t			i;
2352 	int				flag;
2353 	uint32_t			sge_count;
2354 	uint32_t			min_shared_buffers;
2355 	int				max_device_sge = SPDK_NVMF_MAX_SGL_ENTRIES;
2356 	pthread_mutexattr_t		attr;
2357 
2358 	rtransport = calloc(1, sizeof(*rtransport));
2359 	if (!rtransport) {
2360 		return NULL;
2361 	}
2362 
2363 	if (pthread_mutexattr_init(&attr)) {
2364 		SPDK_ERRLOG("pthread_mutexattr_init() failed\n");
2365 		free(rtransport);
2366 		return NULL;
2367 	}
2368 
2369 	if (pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE)) {
2370 		SPDK_ERRLOG("pthread_mutexattr_settype() failed\n");
2371 		pthread_mutexattr_destroy(&attr);
2372 		free(rtransport);
2373 		return NULL;
2374 	}
2375 
2376 	if (pthread_mutex_init(&rtransport->lock, &attr)) {
2377 		SPDK_ERRLOG("pthread_mutex_init() failed\n");
2378 		pthread_mutexattr_destroy(&attr);
2379 		free(rtransport);
2380 		return NULL;
2381 	}
2382 
2383 	pthread_mutexattr_destroy(&attr);
2384 
2385 	TAILQ_INIT(&rtransport->devices);
2386 	TAILQ_INIT(&rtransport->ports);
2387 	TAILQ_INIT(&rtransport->poll_groups);
2388 
2389 	rtransport->transport.ops = &spdk_nvmf_transport_rdma;
2390 
2391 	SPDK_INFOLOG(SPDK_LOG_RDMA, "*** RDMA Transport Init ***\n"
2392 		     "  Transport opts:  max_ioq_depth=%d, max_io_size=%d,\n"
2393 		     "  max_qpairs_per_ctrlr=%d, io_unit_size=%d,\n"
2394 		     "  in_capsule_data_size=%d, max_aq_depth=%d,\n"
2395 		     "  num_shared_buffers=%d, max_srq_depth=%d, no_srq=%d\n",
2396 		     opts->max_queue_depth,
2397 		     opts->max_io_size,
2398 		     opts->max_qpairs_per_ctrlr,
2399 		     opts->io_unit_size,
2400 		     opts->in_capsule_data_size,
2401 		     opts->max_aq_depth,
2402 		     opts->num_shared_buffers,
2403 		     opts->max_srq_depth,
2404 		     opts->no_srq);
2405 
2406 	/* I/O unit size cannot be larger than max I/O size */
2407 	if (opts->io_unit_size > opts->max_io_size) {
2408 		opts->io_unit_size = opts->max_io_size;
2409 	}
2410 
2411 	if (opts->num_shared_buffers < (SPDK_NVMF_MAX_SGL_ENTRIES * 2)) {
2412 		SPDK_ERRLOG("The number of shared data buffers (%d) is less than"
2413 			    "the minimum number required to guarantee that forward progress can be made (%d)\n",
2414 			    opts->num_shared_buffers, (SPDK_NVMF_MAX_SGL_ENTRIES * 2));
2415 		spdk_nvmf_rdma_destroy(&rtransport->transport);
2416 		return NULL;
2417 	}
2418 
2419 	min_shared_buffers = spdk_thread_get_count() * opts->buf_cache_size;
2420 	if (min_shared_buffers > opts->num_shared_buffers) {
2421 		SPDK_ERRLOG("There are not enough buffers to satisfy"
2422 			    "per-poll group caches for each thread. (%" PRIu32 ")"
2423 			    "supplied. (%" PRIu32 ") required\n", opts->num_shared_buffers, min_shared_buffers);
2424 		SPDK_ERRLOG("Please specify a larger number of shared buffers\n");
2425 		spdk_nvmf_rdma_destroy(&rtransport->transport);
2426 		return NULL;
2427 	}
2428 
2429 	sge_count = opts->max_io_size / opts->io_unit_size;
2430 	if (sge_count > NVMF_DEFAULT_TX_SGE) {
2431 		SPDK_ERRLOG("Unsupported IO Unit size specified, %d bytes\n", opts->io_unit_size);
2432 		spdk_nvmf_rdma_destroy(&rtransport->transport);
2433 		return NULL;
2434 	}
2435 
2436 	rtransport->event_channel = rdma_create_event_channel();
2437 	if (rtransport->event_channel == NULL) {
2438 		SPDK_ERRLOG("rdma_create_event_channel() failed, %s\n", spdk_strerror(errno));
2439 		spdk_nvmf_rdma_destroy(&rtransport->transport);
2440 		return NULL;
2441 	}
2442 
2443 	flag = fcntl(rtransport->event_channel->fd, F_GETFL);
2444 	if (fcntl(rtransport->event_channel->fd, F_SETFL, flag | O_NONBLOCK) < 0) {
2445 		SPDK_ERRLOG("fcntl can't set nonblocking mode for socket, fd: %d (%s)\n",
2446 			    rtransport->event_channel->fd, spdk_strerror(errno));
2447 		spdk_nvmf_rdma_destroy(&rtransport->transport);
2448 		return NULL;
2449 	}
2450 
2451 	rtransport->data_wr_pool = spdk_mempool_create("spdk_nvmf_rdma_wr_data",
2452 				   opts->max_queue_depth * SPDK_NVMF_MAX_SGL_ENTRIES,
2453 				   sizeof(struct spdk_nvmf_rdma_request_data),
2454 				   SPDK_MEMPOOL_DEFAULT_CACHE_SIZE,
2455 				   SPDK_ENV_SOCKET_ID_ANY);
2456 	if (!rtransport->data_wr_pool) {
2457 		SPDK_ERRLOG("Unable to allocate work request pool for poll group\n");
2458 		spdk_nvmf_rdma_destroy(&rtransport->transport);
2459 		return NULL;
2460 	}
2461 
2462 	contexts = rdma_get_devices(NULL);
2463 	if (contexts == NULL) {
2464 		SPDK_ERRLOG("rdma_get_devices() failed: %s (%d)\n", spdk_strerror(errno), errno);
2465 		spdk_nvmf_rdma_destroy(&rtransport->transport);
2466 		return NULL;
2467 	}
2468 
2469 	i = 0;
2470 	rc = 0;
2471 	while (contexts[i] != NULL) {
2472 		device = calloc(1, sizeof(*device));
2473 		if (!device) {
2474 			SPDK_ERRLOG("Unable to allocate memory for RDMA devices.\n");
2475 			rc = -ENOMEM;
2476 			break;
2477 		}
2478 		device->context = contexts[i];
2479 		rc = ibv_query_device(device->context, &device->attr);
2480 		if (rc < 0) {
2481 			SPDK_ERRLOG("Failed to query RDMA device attributes.\n");
2482 			free(device);
2483 			break;
2484 
2485 		}
2486 
2487 		max_device_sge = spdk_min(max_device_sge, device->attr.max_sge);
2488 
2489 #ifdef SPDK_CONFIG_RDMA_SEND_WITH_INVAL
2490 		if ((device->attr.device_cap_flags & IBV_DEVICE_MEM_MGT_EXTENSIONS) == 0) {
2491 			SPDK_WARNLOG("The libibverbs on this system supports SEND_WITH_INVALIDATE,");
2492 			SPDK_WARNLOG("but the device with vendor ID %u does not.\n", device->attr.vendor_id);
2493 		}
2494 
2495 		/**
2496 		 * The vendor ID is assigned by the IEEE and an ID of 0 implies Soft-RoCE.
2497 		 * The Soft-RoCE RXE driver does not currently support send with invalidate,
2498 		 * but incorrectly reports that it does. There are changes making their way
2499 		 * through the kernel now that will enable this feature. When they are merged,
2500 		 * we can conditionally enable this feature.
2501 		 *
2502 		 * TODO: enable this for versions of the kernel rxe driver that support it.
2503 		 */
2504 		if (device->attr.vendor_id == 0) {
2505 			device->attr.device_cap_flags &= ~(IBV_DEVICE_MEM_MGT_EXTENSIONS);
2506 		}
2507 #endif
2508 
2509 		/* set up device context async ev fd as NON_BLOCKING */
2510 		flag = fcntl(device->context->async_fd, F_GETFL);
2511 		rc = fcntl(device->context->async_fd, F_SETFL, flag | O_NONBLOCK);
2512 		if (rc < 0) {
2513 			SPDK_ERRLOG("Failed to set context async fd to NONBLOCK.\n");
2514 			free(device);
2515 			break;
2516 		}
2517 
2518 		TAILQ_INSERT_TAIL(&rtransport->devices, device, link);
2519 		i++;
2520 
2521 		if (g_nvmf_hooks.get_ibv_pd) {
2522 			device->pd = g_nvmf_hooks.get_ibv_pd(NULL, device->context);
2523 		} else {
2524 			device->pd = ibv_alloc_pd(device->context);
2525 		}
2526 
2527 		if (!device->pd) {
2528 			SPDK_ERRLOG("Unable to allocate protection domain.\n");
2529 			rc = -ENOMEM;
2530 			break;
2531 		}
2532 
2533 		assert(device->map == NULL);
2534 
2535 		device->map = spdk_mem_map_alloc(0, &g_nvmf_rdma_map_ops, device->pd);
2536 		if (!device->map) {
2537 			SPDK_ERRLOG("Unable to allocate memory map for listen address\n");
2538 			rc = -ENOMEM;
2539 			break;
2540 		}
2541 
2542 		assert(device->map != NULL);
2543 		assert(device->pd != NULL);
2544 	}
2545 	rdma_free_devices(contexts);
2546 
2547 	if (opts->io_unit_size * max_device_sge < opts->max_io_size) {
2548 		/* divide and round up. */
2549 		opts->io_unit_size = (opts->max_io_size + max_device_sge - 1) / max_device_sge;
2550 
2551 		/* round up to the nearest 4k. */
2552 		opts->io_unit_size = (opts->io_unit_size + NVMF_DATA_BUFFER_ALIGNMENT - 1) & ~NVMF_DATA_BUFFER_MASK;
2553 
2554 		opts->io_unit_size = spdk_max(opts->io_unit_size, SPDK_NVMF_RDMA_MIN_IO_BUFFER_SIZE);
2555 		SPDK_NOTICELOG("Adjusting the io unit size to fit the device's maximum I/O size. New I/O unit size %u\n",
2556 			       opts->io_unit_size);
2557 	}
2558 
2559 	if (rc < 0) {
2560 		spdk_nvmf_rdma_destroy(&rtransport->transport);
2561 		return NULL;
2562 	}
2563 
2564 	/* Set up poll descriptor array to monitor events from RDMA and IB
2565 	 * in a single poll syscall
2566 	 */
2567 	rtransport->npoll_fds = i + 1;
2568 	i = 0;
2569 	rtransport->poll_fds = calloc(rtransport->npoll_fds, sizeof(struct pollfd));
2570 	if (rtransport->poll_fds == NULL) {
2571 		SPDK_ERRLOG("poll_fds allocation failed\n");
2572 		spdk_nvmf_rdma_destroy(&rtransport->transport);
2573 		return NULL;
2574 	}
2575 
2576 	rtransport->poll_fds[i].fd = rtransport->event_channel->fd;
2577 	rtransport->poll_fds[i++].events = POLLIN;
2578 
2579 	TAILQ_FOREACH_SAFE(device, &rtransport->devices, link, tmp) {
2580 		rtransport->poll_fds[i].fd = device->context->async_fd;
2581 		rtransport->poll_fds[i++].events = POLLIN;
2582 	}
2583 
2584 	return &rtransport->transport;
2585 }
2586 
2587 static int
2588 spdk_nvmf_rdma_destroy(struct spdk_nvmf_transport *transport)
2589 {
2590 	struct spdk_nvmf_rdma_transport	*rtransport;
2591 	struct spdk_nvmf_rdma_port	*port, *port_tmp;
2592 	struct spdk_nvmf_rdma_device	*device, *device_tmp;
2593 
2594 	rtransport = SPDK_CONTAINEROF(transport, struct spdk_nvmf_rdma_transport, transport);
2595 
2596 	TAILQ_FOREACH_SAFE(port, &rtransport->ports, link, port_tmp) {
2597 		TAILQ_REMOVE(&rtransport->ports, port, link);
2598 		rdma_destroy_id(port->id);
2599 		free(port);
2600 	}
2601 
2602 	if (rtransport->poll_fds != NULL) {
2603 		free(rtransport->poll_fds);
2604 	}
2605 
2606 	if (rtransport->event_channel != NULL) {
2607 		rdma_destroy_event_channel(rtransport->event_channel);
2608 	}
2609 
2610 	TAILQ_FOREACH_SAFE(device, &rtransport->devices, link, device_tmp) {
2611 		TAILQ_REMOVE(&rtransport->devices, device, link);
2612 		if (device->map) {
2613 			spdk_mem_map_free(&device->map);
2614 		}
2615 		if (device->pd) {
2616 			if (!g_nvmf_hooks.get_ibv_pd) {
2617 				ibv_dealloc_pd(device->pd);
2618 			}
2619 		}
2620 		free(device);
2621 	}
2622 
2623 	if (rtransport->data_wr_pool != NULL) {
2624 		if (spdk_mempool_count(rtransport->data_wr_pool) !=
2625 		    (transport->opts.max_queue_depth * SPDK_NVMF_MAX_SGL_ENTRIES)) {
2626 			SPDK_ERRLOG("transport wr pool count is %zu but should be %u\n",
2627 				    spdk_mempool_count(rtransport->data_wr_pool),
2628 				    transport->opts.max_queue_depth * SPDK_NVMF_MAX_SGL_ENTRIES);
2629 		}
2630 	}
2631 
2632 	spdk_mempool_free(rtransport->data_wr_pool);
2633 
2634 	pthread_mutex_destroy(&rtransport->lock);
2635 	free(rtransport);
2636 
2637 	return 0;
2638 }
2639 
2640 static int
2641 spdk_nvmf_rdma_trid_from_cm_id(struct rdma_cm_id *id,
2642 			       struct spdk_nvme_transport_id *trid,
2643 			       bool peer);
2644 
2645 static int
2646 spdk_nvmf_rdma_listen(struct spdk_nvmf_transport *transport,
2647 		      const struct spdk_nvme_transport_id *trid,
2648 		      spdk_nvmf_tgt_listen_done_fn cb_fn,
2649 		      void *cb_arg)
2650 {
2651 	struct spdk_nvmf_rdma_transport	*rtransport;
2652 	struct spdk_nvmf_rdma_device	*device;
2653 	struct spdk_nvmf_rdma_port	*port;
2654 	struct addrinfo			*res;
2655 	struct addrinfo			hints;
2656 	int				family;
2657 	int				rc;
2658 
2659 	rtransport = SPDK_CONTAINEROF(transport, struct spdk_nvmf_rdma_transport, transport);
2660 	assert(rtransport->event_channel != NULL);
2661 
2662 	pthread_mutex_lock(&rtransport->lock);
2663 	TAILQ_FOREACH(port, &rtransport->ports, link) {
2664 		if (spdk_nvme_transport_id_compare(&port->trid, trid) == 0) {
2665 			goto success;
2666 		}
2667 	}
2668 
2669 	port = calloc(1, sizeof(*port));
2670 	if (!port) {
2671 		SPDK_ERRLOG("Port allocation failed\n");
2672 		pthread_mutex_unlock(&rtransport->lock);
2673 		return -ENOMEM;
2674 	}
2675 
2676 	/* Selectively copy the trid. Things like NQN don't matter here - that
2677 	 * mapping is enforced elsewhere.
2678 	 */
2679 	spdk_nvme_trid_populate_transport(&port->trid, SPDK_NVME_TRANSPORT_RDMA);
2680 	port->trid.adrfam = trid->adrfam;
2681 	snprintf(port->trid.traddr, sizeof(port->trid.traddr), "%s", trid->traddr);
2682 	snprintf(port->trid.trsvcid, sizeof(port->trid.trsvcid), "%s", trid->trsvcid);
2683 
2684 	switch (port->trid.adrfam) {
2685 	case SPDK_NVMF_ADRFAM_IPV4:
2686 		family = AF_INET;
2687 		break;
2688 	case SPDK_NVMF_ADRFAM_IPV6:
2689 		family = AF_INET6;
2690 		break;
2691 	default:
2692 		SPDK_ERRLOG("Unhandled ADRFAM %d\n", port->trid.adrfam);
2693 		free(port);
2694 		pthread_mutex_unlock(&rtransport->lock);
2695 		return -EINVAL;
2696 	}
2697 
2698 	memset(&hints, 0, sizeof(hints));
2699 	hints.ai_family = family;
2700 	hints.ai_flags = AI_NUMERICSERV;
2701 	hints.ai_socktype = SOCK_STREAM;
2702 	hints.ai_protocol = 0;
2703 
2704 	rc = getaddrinfo(port->trid.traddr, port->trid.trsvcid, &hints, &res);
2705 	if (rc) {
2706 		SPDK_ERRLOG("getaddrinfo failed: %s (%d)\n", gai_strerror(rc), rc);
2707 		free(port);
2708 		pthread_mutex_unlock(&rtransport->lock);
2709 		return -EINVAL;
2710 	}
2711 
2712 	rc = rdma_create_id(rtransport->event_channel, &port->id, port, RDMA_PS_TCP);
2713 	if (rc < 0) {
2714 		SPDK_ERRLOG("rdma_create_id() failed\n");
2715 		freeaddrinfo(res);
2716 		free(port);
2717 		pthread_mutex_unlock(&rtransport->lock);
2718 		return rc;
2719 	}
2720 
2721 	rc = rdma_bind_addr(port->id, res->ai_addr);
2722 	freeaddrinfo(res);
2723 
2724 	if (rc < 0) {
2725 		SPDK_ERRLOG("rdma_bind_addr() failed\n");
2726 		rdma_destroy_id(port->id);
2727 		free(port);
2728 		pthread_mutex_unlock(&rtransport->lock);
2729 		return rc;
2730 	}
2731 
2732 	if (!port->id->verbs) {
2733 		SPDK_ERRLOG("ibv_context is null\n");
2734 		rdma_destroy_id(port->id);
2735 		free(port);
2736 		pthread_mutex_unlock(&rtransport->lock);
2737 		return -1;
2738 	}
2739 
2740 	rc = rdma_listen(port->id, 10); /* 10 = backlog */
2741 	if (rc < 0) {
2742 		SPDK_ERRLOG("rdma_listen() failed\n");
2743 		rdma_destroy_id(port->id);
2744 		free(port);
2745 		pthread_mutex_unlock(&rtransport->lock);
2746 		return rc;
2747 	}
2748 
2749 	TAILQ_FOREACH(device, &rtransport->devices, link) {
2750 		if (device->context == port->id->verbs) {
2751 			port->device = device;
2752 			break;
2753 		}
2754 	}
2755 	if (!port->device) {
2756 		SPDK_ERRLOG("Accepted a connection with verbs %p, but unable to find a corresponding device.\n",
2757 			    port->id->verbs);
2758 		rdma_destroy_id(port->id);
2759 		free(port);
2760 		pthread_mutex_unlock(&rtransport->lock);
2761 		return -EINVAL;
2762 	}
2763 
2764 	SPDK_NOTICELOG("*** NVMe/RDMA Target Listening on %s port %s ***\n",
2765 		       trid->traddr, trid->trsvcid);
2766 
2767 	TAILQ_INSERT_TAIL(&rtransport->ports, port, link);
2768 
2769 success:
2770 	port->ref++;
2771 	pthread_mutex_unlock(&rtransport->lock);
2772 	if (cb_fn != NULL) {
2773 		cb_fn(cb_arg, 0);
2774 	}
2775 	return 0;
2776 }
2777 
2778 static int
2779 spdk_nvmf_rdma_stop_listen(struct spdk_nvmf_transport *transport,
2780 			   const struct spdk_nvme_transport_id *_trid)
2781 {
2782 	struct spdk_nvmf_rdma_transport *rtransport;
2783 	struct spdk_nvmf_rdma_port *port, *tmp;
2784 	struct spdk_nvme_transport_id trid = {};
2785 
2786 	rtransport = SPDK_CONTAINEROF(transport, struct spdk_nvmf_rdma_transport, transport);
2787 
2788 	/* Selectively copy the trid. Things like NQN don't matter here - that
2789 	 * mapping is enforced elsewhere.
2790 	 */
2791 	spdk_nvme_trid_populate_transport(&trid, SPDK_NVME_TRANSPORT_RDMA);
2792 	trid.adrfam = _trid->adrfam;
2793 	snprintf(trid.traddr, sizeof(port->trid.traddr), "%s", _trid->traddr);
2794 	snprintf(trid.trsvcid, sizeof(port->trid.trsvcid), "%s", _trid->trsvcid);
2795 
2796 	pthread_mutex_lock(&rtransport->lock);
2797 	TAILQ_FOREACH_SAFE(port, &rtransport->ports, link, tmp) {
2798 		if (spdk_nvme_transport_id_compare(&port->trid, &trid) == 0) {
2799 			assert(port->ref > 0);
2800 			port->ref--;
2801 			if (port->ref == 0) {
2802 				TAILQ_REMOVE(&rtransport->ports, port, link);
2803 				rdma_destroy_id(port->id);
2804 				free(port);
2805 			}
2806 			break;
2807 		}
2808 	}
2809 
2810 	pthread_mutex_unlock(&rtransport->lock);
2811 	return 0;
2812 }
2813 
2814 static void
2815 spdk_nvmf_rdma_qpair_process_pending(struct spdk_nvmf_rdma_transport *rtransport,
2816 				     struct spdk_nvmf_rdma_qpair *rqpair, bool drain)
2817 {
2818 	struct spdk_nvmf_request *req, *tmp;
2819 	struct spdk_nvmf_rdma_request	*rdma_req, *req_tmp;
2820 	struct spdk_nvmf_rdma_resources *resources;
2821 
2822 	/* We process I/O in the data transfer pending queue at the highest priority. RDMA reads first */
2823 	STAILQ_FOREACH_SAFE(rdma_req, &rqpair->pending_rdma_read_queue, state_link, req_tmp) {
2824 		if (spdk_nvmf_rdma_request_process(rtransport, rdma_req) == false && drain == false) {
2825 			break;
2826 		}
2827 	}
2828 
2829 	/* Then RDMA writes since reads have stronger restrictions than writes */
2830 	STAILQ_FOREACH_SAFE(rdma_req, &rqpair->pending_rdma_write_queue, state_link, req_tmp) {
2831 		if (spdk_nvmf_rdma_request_process(rtransport, rdma_req) == false && drain == false) {
2832 			break;
2833 		}
2834 	}
2835 
2836 	/* The second highest priority is I/O waiting on memory buffers. */
2837 	STAILQ_FOREACH_SAFE(req, &rqpair->poller->group->group.pending_buf_queue, buf_link, tmp) {
2838 		rdma_req = SPDK_CONTAINEROF(req, struct spdk_nvmf_rdma_request, req);
2839 		if (spdk_nvmf_rdma_request_process(rtransport, rdma_req) == false && drain == false) {
2840 			break;
2841 		}
2842 	}
2843 
2844 	resources = rqpair->resources;
2845 	while (!STAILQ_EMPTY(&resources->free_queue) && !STAILQ_EMPTY(&resources->incoming_queue)) {
2846 		rdma_req = STAILQ_FIRST(&resources->free_queue);
2847 		STAILQ_REMOVE_HEAD(&resources->free_queue, state_link);
2848 		rdma_req->recv = STAILQ_FIRST(&resources->incoming_queue);
2849 		STAILQ_REMOVE_HEAD(&resources->incoming_queue, link);
2850 
2851 		if (rqpair->srq != NULL) {
2852 			rdma_req->req.qpair = &rdma_req->recv->qpair->qpair;
2853 			rdma_req->recv->qpair->qd++;
2854 		} else {
2855 			rqpair->qd++;
2856 		}
2857 
2858 		rdma_req->receive_tsc = rdma_req->recv->receive_tsc;
2859 		rdma_req->state = RDMA_REQUEST_STATE_NEW;
2860 		if (spdk_nvmf_rdma_request_process(rtransport, rdma_req) == false) {
2861 			break;
2862 		}
2863 	}
2864 	if (!STAILQ_EMPTY(&resources->incoming_queue) && STAILQ_EMPTY(&resources->free_queue)) {
2865 		rqpair->poller->stat.pending_free_request++;
2866 	}
2867 }
2868 
2869 static void
2870 _nvmf_rdma_qpair_disconnect(void *ctx)
2871 {
2872 	struct spdk_nvmf_qpair *qpair = ctx;
2873 
2874 	spdk_nvmf_qpair_disconnect(qpair, NULL, NULL);
2875 }
2876 
2877 static void
2878 _nvmf_rdma_try_disconnect(void *ctx)
2879 {
2880 	struct spdk_nvmf_qpair *qpair = ctx;
2881 	struct spdk_nvmf_poll_group *group;
2882 
2883 	/* Read the group out of the qpair. This is normally set and accessed only from
2884 	 * the thread that created the group. Here, we're not on that thread necessarily.
2885 	 * The data member qpair->group begins it's life as NULL and then is assigned to
2886 	 * a pointer and never changes. So fortunately reading this and checking for
2887 	 * non-NULL is thread safe in the x86_64 memory model. */
2888 	group = qpair->group;
2889 
2890 	if (group == NULL) {
2891 		/* The qpair hasn't been assigned to a group yet, so we can't
2892 		 * process a disconnect. Send a message to ourself and try again. */
2893 		spdk_thread_send_msg(spdk_get_thread(), _nvmf_rdma_try_disconnect, qpair);
2894 		return;
2895 	}
2896 
2897 	spdk_thread_send_msg(group->thread, _nvmf_rdma_qpair_disconnect, qpair);
2898 }
2899 
2900 static inline void
2901 spdk_nvmf_rdma_start_disconnect(struct spdk_nvmf_rdma_qpair *rqpair)
2902 {
2903 	if (!__atomic_test_and_set(&rqpair->disconnect_started, __ATOMIC_RELAXED)) {
2904 		_nvmf_rdma_try_disconnect(&rqpair->qpair);
2905 	}
2906 }
2907 
2908 static void nvmf_rdma_destroy_drained_qpair(void *ctx)
2909 {
2910 	struct spdk_nvmf_rdma_qpair *rqpair = ctx;
2911 	struct spdk_nvmf_rdma_transport *rtransport = SPDK_CONTAINEROF(rqpair->qpair.transport,
2912 			struct spdk_nvmf_rdma_transport, transport);
2913 
2914 	/* In non SRQ path, we will reach rqpair->max_queue_depth. In SRQ path, we will get the last_wqe event. */
2915 	if (rqpair->current_send_depth != 0) {
2916 		return;
2917 	}
2918 
2919 	if (rqpair->srq == NULL && rqpair->current_recv_depth != rqpair->max_queue_depth) {
2920 		return;
2921 	}
2922 
2923 	if (rqpair->srq != NULL && rqpair->last_wqe_reached == false) {
2924 		return;
2925 	}
2926 
2927 	spdk_nvmf_rdma_qpair_process_pending(rtransport, rqpair, true);
2928 
2929 	/* Qpair will be destroyed after nvmf layer closes this qpair */
2930 	if (rqpair->qpair.state != SPDK_NVMF_QPAIR_ERROR) {
2931 		return;
2932 	}
2933 
2934 	spdk_nvmf_rdma_qpair_destroy(rqpair);
2935 }
2936 
2937 
2938 static int
2939 nvmf_rdma_disconnect(struct rdma_cm_event *evt)
2940 {
2941 	struct spdk_nvmf_qpair		*qpair;
2942 	struct spdk_nvmf_rdma_qpair	*rqpair;
2943 
2944 	if (evt->id == NULL) {
2945 		SPDK_ERRLOG("disconnect request: missing cm_id\n");
2946 		return -1;
2947 	}
2948 
2949 	qpair = evt->id->context;
2950 	if (qpair == NULL) {
2951 		SPDK_ERRLOG("disconnect request: no active connection\n");
2952 		return -1;
2953 	}
2954 
2955 	rqpair = SPDK_CONTAINEROF(qpair, struct spdk_nvmf_rdma_qpair, qpair);
2956 
2957 	spdk_trace_record(TRACE_RDMA_QP_DISCONNECT, 0, 0, (uintptr_t)rqpair->cm_id, 0);
2958 
2959 	spdk_nvmf_rdma_start_disconnect(rqpair);
2960 
2961 	return 0;
2962 }
2963 
2964 #ifdef DEBUG
2965 static const char *CM_EVENT_STR[] = {
2966 	"RDMA_CM_EVENT_ADDR_RESOLVED",
2967 	"RDMA_CM_EVENT_ADDR_ERROR",
2968 	"RDMA_CM_EVENT_ROUTE_RESOLVED",
2969 	"RDMA_CM_EVENT_ROUTE_ERROR",
2970 	"RDMA_CM_EVENT_CONNECT_REQUEST",
2971 	"RDMA_CM_EVENT_CONNECT_RESPONSE",
2972 	"RDMA_CM_EVENT_CONNECT_ERROR",
2973 	"RDMA_CM_EVENT_UNREACHABLE",
2974 	"RDMA_CM_EVENT_REJECTED",
2975 	"RDMA_CM_EVENT_ESTABLISHED",
2976 	"RDMA_CM_EVENT_DISCONNECTED",
2977 	"RDMA_CM_EVENT_DEVICE_REMOVAL",
2978 	"RDMA_CM_EVENT_MULTICAST_JOIN",
2979 	"RDMA_CM_EVENT_MULTICAST_ERROR",
2980 	"RDMA_CM_EVENT_ADDR_CHANGE",
2981 	"RDMA_CM_EVENT_TIMEWAIT_EXIT"
2982 };
2983 #endif /* DEBUG */
2984 
2985 static void
2986 nvmf_rdma_disconnect_qpairs_on_port(struct spdk_nvmf_rdma_transport *rtransport,
2987 				    struct spdk_nvmf_rdma_port *port)
2988 {
2989 	struct spdk_nvmf_rdma_poll_group	*rgroup;
2990 	struct spdk_nvmf_rdma_poller		*rpoller;
2991 	struct spdk_nvmf_rdma_qpair		*rqpair;
2992 
2993 	TAILQ_FOREACH(rgroup, &rtransport->poll_groups, link) {
2994 		TAILQ_FOREACH(rpoller, &rgroup->pollers, link) {
2995 			TAILQ_FOREACH(rqpair, &rpoller->qpairs, link) {
2996 				if (rqpair->listen_id == port->id) {
2997 					spdk_nvmf_rdma_start_disconnect(rqpair);
2998 				}
2999 			}
3000 		}
3001 	}
3002 }
3003 
3004 static bool
3005 nvmf_rdma_handle_cm_event_addr_change(struct spdk_nvmf_transport *transport,
3006 				      struct rdma_cm_event *event)
3007 {
3008 	struct spdk_nvme_transport_id		trid;
3009 	struct spdk_nvmf_rdma_port		*port;
3010 	struct spdk_nvmf_rdma_transport		*rtransport;
3011 	uint32_t				ref, i;
3012 	bool					event_acked = false;
3013 
3014 	rtransport = SPDK_CONTAINEROF(transport, struct spdk_nvmf_rdma_transport, transport);
3015 	TAILQ_FOREACH(port, &rtransport->ports, link) {
3016 		if (port->id == event->id) {
3017 			SPDK_ERRLOG("ADDR_CHANGE: IP %s:%s migrated\n", port->trid.traddr, port->trid.trsvcid);
3018 			rdma_ack_cm_event(event);
3019 			event_acked = true;
3020 			trid = port->trid;
3021 			ref = port->ref;
3022 			break;
3023 		}
3024 	}
3025 	if (event_acked) {
3026 		nvmf_rdma_disconnect_qpairs_on_port(rtransport, port);
3027 
3028 		for (i = 0; i < ref; i++) {
3029 			spdk_nvmf_rdma_stop_listen(transport, &trid);
3030 		}
3031 		for (i = 0; i < ref; i++) {
3032 			spdk_nvmf_rdma_listen(transport, &trid, NULL, NULL);
3033 		}
3034 	}
3035 	return event_acked;
3036 }
3037 
3038 static void
3039 nvmf_rdma_handle_cm_event_port_removal(struct spdk_nvmf_transport *transport,
3040 				       struct rdma_cm_event *event)
3041 {
3042 	struct spdk_nvmf_rdma_port		*port;
3043 	struct spdk_nvmf_rdma_transport		*rtransport;
3044 	uint32_t				ref, i;
3045 
3046 	port = event->id->context;
3047 	rtransport = SPDK_CONTAINEROF(transport, struct spdk_nvmf_rdma_transport, transport);
3048 	ref = port->ref;
3049 
3050 	SPDK_NOTICELOG("Port %s:%s is being removed\n", port->trid.traddr, port->trid.trsvcid);
3051 
3052 	nvmf_rdma_disconnect_qpairs_on_port(rtransport, port);
3053 
3054 	rdma_ack_cm_event(event);
3055 
3056 	for (i = 0; i < ref; i++) {
3057 		spdk_nvmf_rdma_stop_listen(transport, &port->trid);
3058 	}
3059 }
3060 
3061 static void
3062 spdk_nvmf_process_cm_event(struct spdk_nvmf_transport *transport, new_qpair_fn cb_fn, void *cb_arg)
3063 {
3064 	struct spdk_nvmf_rdma_transport *rtransport;
3065 	struct rdma_cm_event		*event;
3066 	int				rc;
3067 	bool				event_acked;
3068 
3069 	rtransport = SPDK_CONTAINEROF(transport, struct spdk_nvmf_rdma_transport, transport);
3070 
3071 	if (rtransport->event_channel == NULL) {
3072 		return;
3073 	}
3074 
3075 	while (1) {
3076 		event_acked = false;
3077 		rc = rdma_get_cm_event(rtransport->event_channel, &event);
3078 		if (rc) {
3079 			if (errno != EAGAIN && errno != EWOULDBLOCK) {
3080 				SPDK_ERRLOG("Acceptor Event Error: %s\n", spdk_strerror(errno));
3081 			}
3082 			break;
3083 		}
3084 
3085 		SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Acceptor Event: %s\n", CM_EVENT_STR[event->event]);
3086 
3087 		spdk_trace_record(TRACE_RDMA_CM_ASYNC_EVENT, 0, 0, 0, event->event);
3088 
3089 		switch (event->event) {
3090 		case RDMA_CM_EVENT_ADDR_RESOLVED:
3091 		case RDMA_CM_EVENT_ADDR_ERROR:
3092 		case RDMA_CM_EVENT_ROUTE_RESOLVED:
3093 		case RDMA_CM_EVENT_ROUTE_ERROR:
3094 			/* No action required. The target never attempts to resolve routes. */
3095 			break;
3096 		case RDMA_CM_EVENT_CONNECT_REQUEST:
3097 			rc = nvmf_rdma_connect(transport, event, cb_fn, cb_arg);
3098 			if (rc < 0) {
3099 				SPDK_ERRLOG("Unable to process connect event. rc: %d\n", rc);
3100 				break;
3101 			}
3102 			break;
3103 		case RDMA_CM_EVENT_CONNECT_RESPONSE:
3104 			/* The target never initiates a new connection. So this will not occur. */
3105 			break;
3106 		case RDMA_CM_EVENT_CONNECT_ERROR:
3107 			/* Can this happen? The docs say it can, but not sure what causes it. */
3108 			break;
3109 		case RDMA_CM_EVENT_UNREACHABLE:
3110 		case RDMA_CM_EVENT_REJECTED:
3111 			/* These only occur on the client side. */
3112 			break;
3113 		case RDMA_CM_EVENT_ESTABLISHED:
3114 			/* TODO: Should we be waiting for this event anywhere? */
3115 			break;
3116 		case RDMA_CM_EVENT_DISCONNECTED:
3117 			rc = nvmf_rdma_disconnect(event);
3118 			if (rc < 0) {
3119 				SPDK_ERRLOG("Unable to process disconnect event. rc: %d\n", rc);
3120 				break;
3121 			}
3122 			break;
3123 		case RDMA_CM_EVENT_DEVICE_REMOVAL:
3124 			/* In case of device removal, kernel IB part triggers IBV_EVENT_DEVICE_FATAL
3125 			 * which triggers RDMA_CM_EVENT_DEVICE_REMOVAL on all cma_id’s.
3126 			 * Once these events are sent to SPDK, we should release all IB resources and
3127 			 * don't make attempts to call any ibv_query/modify/create functions. We can only call
3128 			 * ibv_destory* functions to release user space memory allocated by IB. All kernel
3129 			 * resources are already cleaned. */
3130 			if (event->id->qp) {
3131 				/* If rdma_cm event has a valid `qp` pointer then the event refers to the
3132 				 * corresponding qpair. Otherwise the event refers to a listening device */
3133 				rc = nvmf_rdma_disconnect(event);
3134 				if (rc < 0) {
3135 					SPDK_ERRLOG("Unable to process disconnect event. rc: %d\n", rc);
3136 					break;
3137 				}
3138 			} else {
3139 				nvmf_rdma_handle_cm_event_port_removal(transport, event);
3140 				event_acked = true;
3141 			}
3142 			break;
3143 		case RDMA_CM_EVENT_MULTICAST_JOIN:
3144 		case RDMA_CM_EVENT_MULTICAST_ERROR:
3145 			/* Multicast is not used */
3146 			break;
3147 		case RDMA_CM_EVENT_ADDR_CHANGE:
3148 			event_acked = nvmf_rdma_handle_cm_event_addr_change(transport, event);
3149 			break;
3150 		case RDMA_CM_EVENT_TIMEWAIT_EXIT:
3151 			/* For now, do nothing. The target never re-uses queue pairs. */
3152 			break;
3153 		default:
3154 			SPDK_ERRLOG("Unexpected Acceptor Event [%d]\n", event->event);
3155 			break;
3156 		}
3157 		if (!event_acked) {
3158 			rdma_ack_cm_event(event);
3159 		}
3160 	}
3161 }
3162 
3163 static void
3164 nvmf_rdma_handle_qp_fatal(struct spdk_nvmf_rdma_qpair *rqpair)
3165 {
3166 	spdk_nvmf_rdma_update_ibv_state(rqpair);
3167 	spdk_nvmf_rdma_start_disconnect(rqpair);
3168 }
3169 
3170 static void
3171 nvmf_rdma_handle_last_wqe_reached(struct spdk_nvmf_rdma_qpair *rqpair)
3172 {
3173 	rqpair->last_wqe_reached = true;
3174 	nvmf_rdma_destroy_drained_qpair(rqpair);
3175 }
3176 
3177 static void
3178 nvmf_rdma_handle_sq_drained(struct spdk_nvmf_rdma_qpair *rqpair)
3179 {
3180 	spdk_nvmf_rdma_start_disconnect(rqpair);
3181 }
3182 
3183 static void
3184 spdk_nvmf_rdma_qpair_process_ibv_event(void *ctx)
3185 {
3186 	struct spdk_nvmf_rdma_ibv_event_ctx *event_ctx = ctx;
3187 
3188 	if (event_ctx->rqpair) {
3189 		STAILQ_REMOVE(&event_ctx->rqpair->ibv_events, event_ctx, spdk_nvmf_rdma_ibv_event_ctx, link);
3190 		if (event_ctx->cb_fn) {
3191 			event_ctx->cb_fn(event_ctx->rqpair);
3192 		}
3193 	}
3194 	free(event_ctx);
3195 }
3196 
3197 static int
3198 spdk_nvmf_rdma_send_qpair_async_event(struct spdk_nvmf_rdma_qpair *rqpair,
3199 				      spdk_nvmf_rdma_qpair_ibv_event fn)
3200 {
3201 	struct spdk_nvmf_rdma_ibv_event_ctx *ctx;
3202 
3203 	if (!rqpair->qpair.group) {
3204 		return EINVAL;
3205 	}
3206 
3207 	ctx = calloc(1, sizeof(*ctx));
3208 	if (!ctx) {
3209 		return ENOMEM;
3210 	}
3211 
3212 	ctx->rqpair = rqpair;
3213 	ctx->cb_fn = fn;
3214 	STAILQ_INSERT_TAIL(&rqpair->ibv_events, ctx, link);
3215 
3216 	return spdk_thread_send_msg(rqpair->qpair.group->thread, spdk_nvmf_rdma_qpair_process_ibv_event,
3217 				    ctx);
3218 }
3219 
3220 static void
3221 spdk_nvmf_process_ib_event(struct spdk_nvmf_rdma_device *device)
3222 {
3223 	int				rc;
3224 	struct spdk_nvmf_rdma_qpair	*rqpair = NULL;
3225 	struct ibv_async_event		event;
3226 
3227 	rc = ibv_get_async_event(device->context, &event);
3228 
3229 	if (rc) {
3230 		SPDK_ERRLOG("Failed to get async_event (%d): %s\n",
3231 			    errno, spdk_strerror(errno));
3232 		return;
3233 	}
3234 
3235 	switch (event.event_type) {
3236 	case IBV_EVENT_QP_FATAL:
3237 		rqpair = event.element.qp->qp_context;
3238 		SPDK_ERRLOG("Fatal event received for rqpair %p\n", rqpair);
3239 		spdk_trace_record(TRACE_RDMA_IBV_ASYNC_EVENT, 0, 0,
3240 				  (uintptr_t)rqpair->cm_id, event.event_type);
3241 		if (spdk_nvmf_rdma_send_qpair_async_event(rqpair, nvmf_rdma_handle_qp_fatal)) {
3242 			SPDK_ERRLOG("Failed to send QP_FATAL event for rqpair %p\n", rqpair);
3243 			nvmf_rdma_handle_qp_fatal(rqpair);
3244 		}
3245 		break;
3246 	case IBV_EVENT_QP_LAST_WQE_REACHED:
3247 		/* This event only occurs for shared receive queues. */
3248 		rqpair = event.element.qp->qp_context;
3249 		SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Last WQE reached event received for rqpair %p\n", rqpair);
3250 		if (spdk_nvmf_rdma_send_qpair_async_event(rqpair, nvmf_rdma_handle_last_wqe_reached)) {
3251 			SPDK_ERRLOG("Failed to send LAST_WQE_REACHED event for rqpair %p\n", rqpair);
3252 			rqpair->last_wqe_reached = true;
3253 		}
3254 		break;
3255 	case IBV_EVENT_SQ_DRAINED:
3256 		/* This event occurs frequently in both error and non-error states.
3257 		 * Check if the qpair is in an error state before sending a message. */
3258 		rqpair = event.element.qp->qp_context;
3259 		SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Last sq drained event received for rqpair %p\n", rqpair);
3260 		spdk_trace_record(TRACE_RDMA_IBV_ASYNC_EVENT, 0, 0,
3261 				  (uintptr_t)rqpair->cm_id, event.event_type);
3262 		if (spdk_nvmf_rdma_update_ibv_state(rqpair) == IBV_QPS_ERR) {
3263 			if (spdk_nvmf_rdma_send_qpair_async_event(rqpair, nvmf_rdma_handle_sq_drained)) {
3264 				SPDK_ERRLOG("Failed to send SQ_DRAINED event for rqpair %p\n", rqpair);
3265 				nvmf_rdma_handle_sq_drained(rqpair);
3266 			}
3267 		}
3268 		break;
3269 	case IBV_EVENT_QP_REQ_ERR:
3270 	case IBV_EVENT_QP_ACCESS_ERR:
3271 	case IBV_EVENT_COMM_EST:
3272 	case IBV_EVENT_PATH_MIG:
3273 	case IBV_EVENT_PATH_MIG_ERR:
3274 		SPDK_NOTICELOG("Async event: %s\n",
3275 			       ibv_event_type_str(event.event_type));
3276 		rqpair = event.element.qp->qp_context;
3277 		spdk_trace_record(TRACE_RDMA_IBV_ASYNC_EVENT, 0, 0,
3278 				  (uintptr_t)rqpair->cm_id, event.event_type);
3279 		spdk_nvmf_rdma_update_ibv_state(rqpair);
3280 		break;
3281 	case IBV_EVENT_CQ_ERR:
3282 	case IBV_EVENT_DEVICE_FATAL:
3283 	case IBV_EVENT_PORT_ACTIVE:
3284 	case IBV_EVENT_PORT_ERR:
3285 	case IBV_EVENT_LID_CHANGE:
3286 	case IBV_EVENT_PKEY_CHANGE:
3287 	case IBV_EVENT_SM_CHANGE:
3288 	case IBV_EVENT_SRQ_ERR:
3289 	case IBV_EVENT_SRQ_LIMIT_REACHED:
3290 	case IBV_EVENT_CLIENT_REREGISTER:
3291 	case IBV_EVENT_GID_CHANGE:
3292 	default:
3293 		SPDK_NOTICELOG("Async event: %s\n",
3294 			       ibv_event_type_str(event.event_type));
3295 		spdk_trace_record(TRACE_RDMA_IBV_ASYNC_EVENT, 0, 0, 0, event.event_type);
3296 		break;
3297 	}
3298 	ibv_ack_async_event(&event);
3299 }
3300 
3301 static void
3302 spdk_nvmf_rdma_accept(struct spdk_nvmf_transport *transport, new_qpair_fn cb_fn, void *cb_arg)
3303 {
3304 	int	nfds, i = 0;
3305 	struct spdk_nvmf_rdma_transport *rtransport;
3306 	struct spdk_nvmf_rdma_device *device, *tmp;
3307 
3308 	rtransport = SPDK_CONTAINEROF(transport, struct spdk_nvmf_rdma_transport, transport);
3309 	nfds = poll(rtransport->poll_fds, rtransport->npoll_fds, 0);
3310 
3311 	if (nfds <= 0) {
3312 		return;
3313 	}
3314 
3315 	/* The first poll descriptor is RDMA CM event */
3316 	if (rtransport->poll_fds[i++].revents & POLLIN) {
3317 		spdk_nvmf_process_cm_event(transport, cb_fn, cb_arg);
3318 		nfds--;
3319 	}
3320 
3321 	if (nfds == 0) {
3322 		return;
3323 	}
3324 
3325 	/* Second and subsequent poll descriptors are IB async events */
3326 	TAILQ_FOREACH_SAFE(device, &rtransport->devices, link, tmp) {
3327 		if (rtransport->poll_fds[i++].revents & POLLIN) {
3328 			spdk_nvmf_process_ib_event(device);
3329 			nfds--;
3330 		}
3331 	}
3332 	/* check all flagged fd's have been served */
3333 	assert(nfds == 0);
3334 }
3335 
3336 static void
3337 spdk_nvmf_rdma_discover(struct spdk_nvmf_transport *transport,
3338 			struct spdk_nvme_transport_id *trid,
3339 			struct spdk_nvmf_discovery_log_page_entry *entry)
3340 {
3341 	entry->trtype = SPDK_NVMF_TRTYPE_RDMA;
3342 	entry->adrfam = trid->adrfam;
3343 	entry->treq.secure_channel = SPDK_NVMF_TREQ_SECURE_CHANNEL_NOT_REQUIRED;
3344 
3345 	spdk_strcpy_pad(entry->trsvcid, trid->trsvcid, sizeof(entry->trsvcid), ' ');
3346 	spdk_strcpy_pad(entry->traddr, trid->traddr, sizeof(entry->traddr), ' ');
3347 
3348 	entry->tsas.rdma.rdma_qptype = SPDK_NVMF_RDMA_QPTYPE_RELIABLE_CONNECTED;
3349 	entry->tsas.rdma.rdma_prtype = SPDK_NVMF_RDMA_PRTYPE_NONE;
3350 	entry->tsas.rdma.rdma_cms = SPDK_NVMF_RDMA_CMS_RDMA_CM;
3351 }
3352 
3353 static void
3354 spdk_nvmf_rdma_poll_group_destroy(struct spdk_nvmf_transport_poll_group *group);
3355 
3356 static struct spdk_nvmf_transport_poll_group *
3357 spdk_nvmf_rdma_poll_group_create(struct spdk_nvmf_transport *transport)
3358 {
3359 	struct spdk_nvmf_rdma_transport		*rtransport;
3360 	struct spdk_nvmf_rdma_poll_group	*rgroup;
3361 	struct spdk_nvmf_rdma_poller		*poller;
3362 	struct spdk_nvmf_rdma_device		*device;
3363 	struct ibv_srq_init_attr		srq_init_attr;
3364 	struct spdk_nvmf_rdma_resource_opts	opts;
3365 	int					num_cqe;
3366 
3367 	rtransport = SPDK_CONTAINEROF(transport, struct spdk_nvmf_rdma_transport, transport);
3368 
3369 	rgroup = calloc(1, sizeof(*rgroup));
3370 	if (!rgroup) {
3371 		return NULL;
3372 	}
3373 
3374 	TAILQ_INIT(&rgroup->pollers);
3375 	STAILQ_INIT(&rgroup->retired_bufs);
3376 
3377 	pthread_mutex_lock(&rtransport->lock);
3378 	TAILQ_FOREACH(device, &rtransport->devices, link) {
3379 		poller = calloc(1, sizeof(*poller));
3380 		if (!poller) {
3381 			SPDK_ERRLOG("Unable to allocate memory for new RDMA poller\n");
3382 			spdk_nvmf_rdma_poll_group_destroy(&rgroup->group);
3383 			pthread_mutex_unlock(&rtransport->lock);
3384 			return NULL;
3385 		}
3386 
3387 		poller->device = device;
3388 		poller->group = rgroup;
3389 
3390 		TAILQ_INIT(&poller->qpairs);
3391 		STAILQ_INIT(&poller->qpairs_pending_send);
3392 		STAILQ_INIT(&poller->qpairs_pending_recv);
3393 
3394 		TAILQ_INSERT_TAIL(&rgroup->pollers, poller, link);
3395 		if (transport->opts.no_srq == false && device->num_srq < device->attr.max_srq) {
3396 			poller->max_srq_depth = transport->opts.max_srq_depth;
3397 
3398 			device->num_srq++;
3399 			memset(&srq_init_attr, 0, sizeof(struct ibv_srq_init_attr));
3400 			srq_init_attr.attr.max_wr = poller->max_srq_depth;
3401 			srq_init_attr.attr.max_sge = spdk_min(device->attr.max_sge, NVMF_DEFAULT_RX_SGE);
3402 			poller->srq = ibv_create_srq(device->pd, &srq_init_attr);
3403 			if (!poller->srq) {
3404 				SPDK_ERRLOG("Unable to create shared receive queue, errno %d\n", errno);
3405 				spdk_nvmf_rdma_poll_group_destroy(&rgroup->group);
3406 				pthread_mutex_unlock(&rtransport->lock);
3407 				return NULL;
3408 			}
3409 
3410 			opts.qp = poller->srq;
3411 			opts.pd = device->pd;
3412 			opts.qpair = NULL;
3413 			opts.shared = true;
3414 			opts.max_queue_depth = poller->max_srq_depth;
3415 			opts.in_capsule_data_size = transport->opts.in_capsule_data_size;
3416 
3417 			poller->resources = nvmf_rdma_resources_create(&opts);
3418 			if (!poller->resources) {
3419 				SPDK_ERRLOG("Unable to allocate resources for shared receive queue.\n");
3420 				spdk_nvmf_rdma_poll_group_destroy(&rgroup->group);
3421 				pthread_mutex_unlock(&rtransport->lock);
3422 				return NULL;
3423 			}
3424 		}
3425 
3426 		/*
3427 		 * When using an srq, we can limit the completion queue at startup.
3428 		 * The following formula represents the calculation:
3429 		 * num_cqe = num_recv + num_data_wr + num_send_wr.
3430 		 * where num_recv=num_data_wr=and num_send_wr=poller->max_srq_depth
3431 		 */
3432 		if (poller->srq) {
3433 			num_cqe = poller->max_srq_depth * 3;
3434 		} else {
3435 			num_cqe = DEFAULT_NVMF_RDMA_CQ_SIZE;
3436 		}
3437 
3438 		poller->cq = ibv_create_cq(device->context, num_cqe, poller, NULL, 0);
3439 		if (!poller->cq) {
3440 			SPDK_ERRLOG("Unable to create completion queue\n");
3441 			spdk_nvmf_rdma_poll_group_destroy(&rgroup->group);
3442 			pthread_mutex_unlock(&rtransport->lock);
3443 			return NULL;
3444 		}
3445 		poller->num_cqe = num_cqe;
3446 	}
3447 
3448 	TAILQ_INSERT_TAIL(&rtransport->poll_groups, rgroup, link);
3449 	if (rtransport->conn_sched.next_admin_pg == NULL) {
3450 		rtransport->conn_sched.next_admin_pg = rgroup;
3451 		rtransport->conn_sched.next_io_pg = rgroup;
3452 	}
3453 
3454 	pthread_mutex_unlock(&rtransport->lock);
3455 	return &rgroup->group;
3456 }
3457 
3458 static struct spdk_nvmf_transport_poll_group *
3459 spdk_nvmf_rdma_get_optimal_poll_group(struct spdk_nvmf_qpair *qpair)
3460 {
3461 	struct spdk_nvmf_rdma_transport *rtransport;
3462 	struct spdk_nvmf_rdma_poll_group **pg;
3463 	struct spdk_nvmf_transport_poll_group *result;
3464 
3465 	rtransport = SPDK_CONTAINEROF(qpair->transport, struct spdk_nvmf_rdma_transport, transport);
3466 
3467 	pthread_mutex_lock(&rtransport->lock);
3468 
3469 	if (TAILQ_EMPTY(&rtransport->poll_groups)) {
3470 		pthread_mutex_unlock(&rtransport->lock);
3471 		return NULL;
3472 	}
3473 
3474 	if (qpair->qid == 0) {
3475 		pg = &rtransport->conn_sched.next_admin_pg;
3476 	} else {
3477 		pg = &rtransport->conn_sched.next_io_pg;
3478 	}
3479 
3480 	assert(*pg != NULL);
3481 
3482 	result = &(*pg)->group;
3483 
3484 	*pg = TAILQ_NEXT(*pg, link);
3485 	if (*pg == NULL) {
3486 		*pg = TAILQ_FIRST(&rtransport->poll_groups);
3487 	}
3488 
3489 	pthread_mutex_unlock(&rtransport->lock);
3490 
3491 	return result;
3492 }
3493 
3494 static void
3495 spdk_nvmf_rdma_poll_group_destroy(struct spdk_nvmf_transport_poll_group *group)
3496 {
3497 	struct spdk_nvmf_rdma_poll_group	*rgroup, *next_rgroup;
3498 	struct spdk_nvmf_rdma_poller		*poller, *tmp;
3499 	struct spdk_nvmf_rdma_qpair		*qpair, *tmp_qpair;
3500 	struct spdk_nvmf_transport_pg_cache_buf	*buf, *tmp_buf;
3501 	struct spdk_nvmf_rdma_transport		*rtransport;
3502 
3503 	rgroup = SPDK_CONTAINEROF(group, struct spdk_nvmf_rdma_poll_group, group);
3504 	if (!rgroup) {
3505 		return;
3506 	}
3507 
3508 	/* free all retired buffers back to the transport so we don't short the mempool. */
3509 	STAILQ_FOREACH_SAFE(buf, &rgroup->retired_bufs, link, tmp_buf) {
3510 		STAILQ_REMOVE(&rgroup->retired_bufs, buf, spdk_nvmf_transport_pg_cache_buf, link);
3511 		assert(group->transport != NULL);
3512 		spdk_mempool_put(group->transport->data_buf_pool, buf);
3513 	}
3514 
3515 	TAILQ_FOREACH_SAFE(poller, &rgroup->pollers, link, tmp) {
3516 		TAILQ_REMOVE(&rgroup->pollers, poller, link);
3517 
3518 		TAILQ_FOREACH_SAFE(qpair, &poller->qpairs, link, tmp_qpair) {
3519 			spdk_nvmf_rdma_qpair_destroy(qpair);
3520 		}
3521 
3522 		if (poller->srq) {
3523 			nvmf_rdma_resources_destroy(poller->resources);
3524 			ibv_destroy_srq(poller->srq);
3525 			SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Destroyed RDMA shared queue %p\n", poller->srq);
3526 		}
3527 
3528 		if (poller->cq) {
3529 			ibv_destroy_cq(poller->cq);
3530 		}
3531 
3532 		free(poller);
3533 	}
3534 
3535 	if (rgroup->group.transport == NULL) {
3536 		/* Transport can be NULL when spdk_nvmf_rdma_poll_group_create()
3537 		 * calls this function directly in a failure path. */
3538 		free(rgroup);
3539 		return;
3540 	}
3541 
3542 	rtransport = SPDK_CONTAINEROF(rgroup->group.transport, struct spdk_nvmf_rdma_transport, transport);
3543 
3544 	pthread_mutex_lock(&rtransport->lock);
3545 	next_rgroup = TAILQ_NEXT(rgroup, link);
3546 	TAILQ_REMOVE(&rtransport->poll_groups, rgroup, link);
3547 	if (next_rgroup == NULL) {
3548 		next_rgroup = TAILQ_FIRST(&rtransport->poll_groups);
3549 	}
3550 	if (rtransport->conn_sched.next_admin_pg == rgroup) {
3551 		rtransport->conn_sched.next_admin_pg = next_rgroup;
3552 	}
3553 	if (rtransport->conn_sched.next_io_pg == rgroup) {
3554 		rtransport->conn_sched.next_io_pg = next_rgroup;
3555 	}
3556 	pthread_mutex_unlock(&rtransport->lock);
3557 
3558 	free(rgroup);
3559 }
3560 
3561 static void
3562 spdk_nvmf_rdma_qpair_reject_connection(struct spdk_nvmf_rdma_qpair *rqpair)
3563 {
3564 	if (rqpair->cm_id != NULL) {
3565 		spdk_nvmf_rdma_event_reject(rqpair->cm_id, SPDK_NVMF_RDMA_ERROR_NO_RESOURCES);
3566 	}
3567 	spdk_nvmf_rdma_qpair_destroy(rqpair);
3568 }
3569 
3570 static int
3571 spdk_nvmf_rdma_poll_group_add(struct spdk_nvmf_transport_poll_group *group,
3572 			      struct spdk_nvmf_qpair *qpair)
3573 {
3574 	struct spdk_nvmf_rdma_poll_group	*rgroup;
3575 	struct spdk_nvmf_rdma_qpair		*rqpair;
3576 	struct spdk_nvmf_rdma_device		*device;
3577 	struct spdk_nvmf_rdma_poller		*poller;
3578 	int					rc;
3579 
3580 	rgroup = SPDK_CONTAINEROF(group, struct spdk_nvmf_rdma_poll_group, group);
3581 	rqpair = SPDK_CONTAINEROF(qpair, struct spdk_nvmf_rdma_qpair, qpair);
3582 
3583 	device = rqpair->device;
3584 
3585 	TAILQ_FOREACH(poller, &rgroup->pollers, link) {
3586 		if (poller->device == device) {
3587 			break;
3588 		}
3589 	}
3590 
3591 	if (!poller) {
3592 		SPDK_ERRLOG("No poller found for device.\n");
3593 		return -1;
3594 	}
3595 
3596 	TAILQ_INSERT_TAIL(&poller->qpairs, rqpair, link);
3597 	rqpair->poller = poller;
3598 	rqpair->srq = rqpair->poller->srq;
3599 
3600 	rc = spdk_nvmf_rdma_qpair_initialize(qpair);
3601 	if (rc < 0) {
3602 		SPDK_ERRLOG("Failed to initialize nvmf_rdma_qpair with qpair=%p\n", qpair);
3603 		return -1;
3604 	}
3605 
3606 	rc = spdk_nvmf_rdma_event_accept(rqpair->cm_id, rqpair);
3607 	if (rc) {
3608 		/* Try to reject, but we probably can't */
3609 		spdk_nvmf_rdma_qpair_reject_connection(rqpair);
3610 		return -1;
3611 	}
3612 
3613 	spdk_nvmf_rdma_update_ibv_state(rqpair);
3614 
3615 	return 0;
3616 }
3617 
3618 static int
3619 spdk_nvmf_rdma_request_free(struct spdk_nvmf_request *req)
3620 {
3621 	struct spdk_nvmf_rdma_request	*rdma_req = SPDK_CONTAINEROF(req, struct spdk_nvmf_rdma_request, req);
3622 	struct spdk_nvmf_rdma_transport	*rtransport = SPDK_CONTAINEROF(req->qpair->transport,
3623 			struct spdk_nvmf_rdma_transport, transport);
3624 
3625 	nvmf_rdma_request_free(rdma_req, rtransport);
3626 	return 0;
3627 }
3628 
3629 static int
3630 spdk_nvmf_rdma_request_complete(struct spdk_nvmf_request *req)
3631 {
3632 	struct spdk_nvmf_rdma_transport	*rtransport = SPDK_CONTAINEROF(req->qpair->transport,
3633 			struct spdk_nvmf_rdma_transport, transport);
3634 	struct spdk_nvmf_rdma_request	*rdma_req = SPDK_CONTAINEROF(req,
3635 			struct spdk_nvmf_rdma_request, req);
3636 	struct spdk_nvmf_rdma_qpair     *rqpair = SPDK_CONTAINEROF(rdma_req->req.qpair,
3637 			struct spdk_nvmf_rdma_qpair, qpair);
3638 
3639 	if (rqpair->ibv_state != IBV_QPS_ERR) {
3640 		/* The connection is alive, so process the request as normal */
3641 		rdma_req->state = RDMA_REQUEST_STATE_EXECUTED;
3642 	} else {
3643 		/* The connection is dead. Move the request directly to the completed state. */
3644 		rdma_req->state = RDMA_REQUEST_STATE_COMPLETED;
3645 	}
3646 
3647 	spdk_nvmf_rdma_request_process(rtransport, rdma_req);
3648 
3649 	return 0;
3650 }
3651 
3652 static int
3653 spdk_nvmf_rdma_destroy_defunct_qpair(void *ctx)
3654 {
3655 	struct spdk_nvmf_rdma_qpair	*rqpair = ctx;
3656 	struct spdk_nvmf_rdma_transport *rtransport = SPDK_CONTAINEROF(rqpair->qpair.transport,
3657 			struct spdk_nvmf_rdma_transport, transport);
3658 
3659 	SPDK_INFOLOG(SPDK_LOG_RDMA, "QP#%d hasn't been drained as expected, manually destroy it\n",
3660 		     rqpair->qpair.qid);
3661 
3662 	spdk_nvmf_rdma_qpair_process_pending(rtransport, rqpair, true);
3663 	spdk_nvmf_rdma_qpair_destroy(rqpair);
3664 
3665 	return 0;
3666 }
3667 
3668 static void
3669 spdk_nvmf_rdma_close_qpair(struct spdk_nvmf_qpair *qpair)
3670 {
3671 	struct spdk_nvmf_rdma_qpair *rqpair = SPDK_CONTAINEROF(qpair, struct spdk_nvmf_rdma_qpair, qpair);
3672 
3673 	if (rqpair->disconnect_flags & RDMA_QP_DISCONNECTING) {
3674 		return;
3675 	}
3676 
3677 	rqpair->disconnect_flags |= RDMA_QP_DISCONNECTING;
3678 
3679 	/* This happens only when the qpair is disconnected before
3680 	 * it is added to the poll group. Since there is no poll group,
3681 	 * the RDMA qp has not been initialized yet and the RDMA CM
3682 	 * event has not yet been acknowledged, so we need to reject it.
3683 	 */
3684 	if (rqpair->qpair.state == SPDK_NVMF_QPAIR_UNINITIALIZED) {
3685 		spdk_nvmf_rdma_qpair_reject_connection(rqpair);
3686 		return;
3687 	}
3688 
3689 	if (rqpair->ibv_state != IBV_QPS_ERR) {
3690 		spdk_nvmf_rdma_set_ibv_state(rqpair, IBV_QPS_ERR);
3691 	}
3692 
3693 	rqpair->destruct_poller = spdk_poller_register(spdk_nvmf_rdma_destroy_defunct_qpair, (void *)rqpair,
3694 				  NVMF_RDMA_QPAIR_DESTROY_TIMEOUT_US);
3695 }
3696 
3697 static struct spdk_nvmf_rdma_qpair *
3698 get_rdma_qpair_from_wc(struct spdk_nvmf_rdma_poller *rpoller, struct ibv_wc *wc)
3699 {
3700 	struct spdk_nvmf_rdma_qpair *rqpair;
3701 	/* @todo: improve QP search */
3702 	TAILQ_FOREACH(rqpair, &rpoller->qpairs, link) {
3703 		if (wc->qp_num == rqpair->cm_id->qp->qp_num) {
3704 			return rqpair;
3705 		}
3706 	}
3707 	SPDK_ERRLOG("Didn't find QP with qp_num %u\n", wc->qp_num);
3708 	return NULL;
3709 }
3710 
3711 #ifdef DEBUG
3712 static int
3713 spdk_nvmf_rdma_req_is_completing(struct spdk_nvmf_rdma_request *rdma_req)
3714 {
3715 	return rdma_req->state == RDMA_REQUEST_STATE_TRANSFERRING_CONTROLLER_TO_HOST ||
3716 	       rdma_req->state == RDMA_REQUEST_STATE_COMPLETING;
3717 }
3718 #endif
3719 
3720 static void
3721 _poller_reset_failed_recvs(struct spdk_nvmf_rdma_poller *rpoller, struct ibv_recv_wr *bad_recv_wr,
3722 			   int rc)
3723 {
3724 	struct spdk_nvmf_rdma_recv	*rdma_recv;
3725 	struct spdk_nvmf_rdma_wr	*bad_rdma_wr;
3726 
3727 	SPDK_ERRLOG("Failed to post a recv for the poller %p with errno %d\n", rpoller, -rc);
3728 	while (bad_recv_wr != NULL) {
3729 		bad_rdma_wr = (struct spdk_nvmf_rdma_wr *)bad_recv_wr->wr_id;
3730 		rdma_recv = SPDK_CONTAINEROF(bad_rdma_wr, struct spdk_nvmf_rdma_recv, rdma_wr);
3731 
3732 		rdma_recv->qpair->current_recv_depth++;
3733 		bad_recv_wr = bad_recv_wr->next;
3734 		SPDK_ERRLOG("Failed to post a recv for the qpair %p with errno %d\n", rdma_recv->qpair, -rc);
3735 		spdk_nvmf_rdma_start_disconnect(rdma_recv->qpair);
3736 	}
3737 }
3738 
3739 static void
3740 _qp_reset_failed_recvs(struct spdk_nvmf_rdma_qpair *rqpair, struct ibv_recv_wr *bad_recv_wr, int rc)
3741 {
3742 	SPDK_ERRLOG("Failed to post a recv for the qpair %p with errno %d\n", rqpair, -rc);
3743 	while (bad_recv_wr != NULL) {
3744 		bad_recv_wr = bad_recv_wr->next;
3745 		rqpair->current_recv_depth++;
3746 	}
3747 	spdk_nvmf_rdma_start_disconnect(rqpair);
3748 }
3749 
3750 static void
3751 _poller_submit_recvs(struct spdk_nvmf_rdma_transport *rtransport,
3752 		     struct spdk_nvmf_rdma_poller *rpoller)
3753 {
3754 	struct spdk_nvmf_rdma_qpair	*rqpair;
3755 	struct ibv_recv_wr		*bad_recv_wr;
3756 	int				rc;
3757 
3758 	if (rpoller->srq) {
3759 		if (rpoller->resources->recvs_to_post.first != NULL) {
3760 			rc = ibv_post_srq_recv(rpoller->srq, rpoller->resources->recvs_to_post.first, &bad_recv_wr);
3761 			if (rc) {
3762 				_poller_reset_failed_recvs(rpoller, bad_recv_wr, rc);
3763 			}
3764 			rpoller->resources->recvs_to_post.first = NULL;
3765 			rpoller->resources->recvs_to_post.last = NULL;
3766 		}
3767 	} else {
3768 		while (!STAILQ_EMPTY(&rpoller->qpairs_pending_recv)) {
3769 			rqpair = STAILQ_FIRST(&rpoller->qpairs_pending_recv);
3770 			assert(rqpair->resources->recvs_to_post.first != NULL);
3771 			rc = ibv_post_recv(rqpair->cm_id->qp, rqpair->resources->recvs_to_post.first, &bad_recv_wr);
3772 			if (rc) {
3773 				_qp_reset_failed_recvs(rqpair, bad_recv_wr, rc);
3774 			}
3775 			rqpair->resources->recvs_to_post.first = NULL;
3776 			rqpair->resources->recvs_to_post.last = NULL;
3777 			STAILQ_REMOVE_HEAD(&rpoller->qpairs_pending_recv, recv_link);
3778 		}
3779 	}
3780 }
3781 
3782 static void
3783 _qp_reset_failed_sends(struct spdk_nvmf_rdma_transport *rtransport,
3784 		       struct spdk_nvmf_rdma_qpair *rqpair, struct ibv_send_wr *bad_wr, int rc)
3785 {
3786 	struct spdk_nvmf_rdma_wr	*bad_rdma_wr;
3787 	struct spdk_nvmf_rdma_request	*prev_rdma_req = NULL, *cur_rdma_req = NULL;
3788 
3789 	SPDK_ERRLOG("Failed to post a send for the qpair %p with errno %d\n", rqpair, -rc);
3790 	for (; bad_wr != NULL; bad_wr = bad_wr->next) {
3791 		bad_rdma_wr = (struct spdk_nvmf_rdma_wr *)bad_wr->wr_id;
3792 		assert(rqpair->current_send_depth > 0);
3793 		rqpair->current_send_depth--;
3794 		switch (bad_rdma_wr->type) {
3795 		case RDMA_WR_TYPE_DATA:
3796 			cur_rdma_req = SPDK_CONTAINEROF(bad_rdma_wr, struct spdk_nvmf_rdma_request, data.rdma_wr);
3797 			if (bad_wr->opcode == IBV_WR_RDMA_READ) {
3798 				assert(rqpair->current_read_depth > 0);
3799 				rqpair->current_read_depth--;
3800 			}
3801 			break;
3802 		case RDMA_WR_TYPE_SEND:
3803 			cur_rdma_req = SPDK_CONTAINEROF(bad_rdma_wr, struct spdk_nvmf_rdma_request, rsp.rdma_wr);
3804 			break;
3805 		default:
3806 			SPDK_ERRLOG("Found a RECV in the list of pending SEND requests for qpair %p\n", rqpair);
3807 			prev_rdma_req = cur_rdma_req;
3808 			continue;
3809 		}
3810 
3811 		if (prev_rdma_req == cur_rdma_req) {
3812 			/* this request was handled by an earlier wr. i.e. we were performing an nvme read. */
3813 			/* We only have to check against prev_wr since each requests wrs are contiguous in this list. */
3814 			continue;
3815 		}
3816 
3817 		switch (cur_rdma_req->state) {
3818 		case RDMA_REQUEST_STATE_TRANSFERRING_HOST_TO_CONTROLLER:
3819 			cur_rdma_req->req.rsp->nvme_cpl.status.sc = SPDK_NVME_SC_INTERNAL_DEVICE_ERROR;
3820 			cur_rdma_req->state = RDMA_REQUEST_STATE_READY_TO_COMPLETE;
3821 			break;
3822 		case RDMA_REQUEST_STATE_TRANSFERRING_CONTROLLER_TO_HOST:
3823 		case RDMA_REQUEST_STATE_COMPLETING:
3824 			cur_rdma_req->state = RDMA_REQUEST_STATE_COMPLETED;
3825 			break;
3826 		default:
3827 			SPDK_ERRLOG("Found a request in a bad state %d when draining pending SEND requests for qpair %p\n",
3828 				    cur_rdma_req->state, rqpair);
3829 			continue;
3830 		}
3831 
3832 		spdk_nvmf_rdma_request_process(rtransport, cur_rdma_req);
3833 		prev_rdma_req = cur_rdma_req;
3834 	}
3835 
3836 	if (rqpair->qpair.state == SPDK_NVMF_QPAIR_ACTIVE) {
3837 		/* Disconnect the connection. */
3838 		spdk_nvmf_rdma_start_disconnect(rqpair);
3839 	}
3840 
3841 }
3842 
3843 static void
3844 _poller_submit_sends(struct spdk_nvmf_rdma_transport *rtransport,
3845 		     struct spdk_nvmf_rdma_poller *rpoller)
3846 {
3847 	struct spdk_nvmf_rdma_qpair	*rqpair;
3848 	struct ibv_send_wr		*bad_wr = NULL;
3849 	int				rc;
3850 
3851 	while (!STAILQ_EMPTY(&rpoller->qpairs_pending_send)) {
3852 		rqpair = STAILQ_FIRST(&rpoller->qpairs_pending_send);
3853 		assert(rqpair->sends_to_post.first != NULL);
3854 		rc = ibv_post_send(rqpair->cm_id->qp, rqpair->sends_to_post.first, &bad_wr);
3855 
3856 		/* bad wr always points to the first wr that failed. */
3857 		if (rc) {
3858 			_qp_reset_failed_sends(rtransport, rqpair, bad_wr, rc);
3859 		}
3860 		rqpair->sends_to_post.first = NULL;
3861 		rqpair->sends_to_post.last = NULL;
3862 		STAILQ_REMOVE_HEAD(&rpoller->qpairs_pending_send, send_link);
3863 	}
3864 }
3865 
3866 static int
3867 spdk_nvmf_rdma_poller_poll(struct spdk_nvmf_rdma_transport *rtransport,
3868 			   struct spdk_nvmf_rdma_poller *rpoller)
3869 {
3870 	struct ibv_wc wc[32];
3871 	struct spdk_nvmf_rdma_wr	*rdma_wr;
3872 	struct spdk_nvmf_rdma_request	*rdma_req;
3873 	struct spdk_nvmf_rdma_recv	*rdma_recv;
3874 	struct spdk_nvmf_rdma_qpair	*rqpair;
3875 	int reaped, i;
3876 	int count = 0;
3877 	bool error = false;
3878 	uint64_t poll_tsc = spdk_get_ticks();
3879 
3880 	/* Poll for completing operations. */
3881 	reaped = ibv_poll_cq(rpoller->cq, 32, wc);
3882 	if (reaped < 0) {
3883 		SPDK_ERRLOG("Error polling CQ! (%d): %s\n",
3884 			    errno, spdk_strerror(errno));
3885 		return -1;
3886 	}
3887 
3888 	rpoller->stat.polls++;
3889 	rpoller->stat.completions += reaped;
3890 
3891 	for (i = 0; i < reaped; i++) {
3892 
3893 		rdma_wr = (struct spdk_nvmf_rdma_wr *)wc[i].wr_id;
3894 
3895 		switch (rdma_wr->type) {
3896 		case RDMA_WR_TYPE_SEND:
3897 			rdma_req = SPDK_CONTAINEROF(rdma_wr, struct spdk_nvmf_rdma_request, rsp.rdma_wr);
3898 			rqpair = SPDK_CONTAINEROF(rdma_req->req.qpair, struct spdk_nvmf_rdma_qpair, qpair);
3899 
3900 			if (!wc[i].status) {
3901 				count++;
3902 				assert(wc[i].opcode == IBV_WC_SEND);
3903 				assert(spdk_nvmf_rdma_req_is_completing(rdma_req));
3904 			} else {
3905 				SPDK_ERRLOG("data=%p length=%u\n", rdma_req->req.data, rdma_req->req.length);
3906 			}
3907 
3908 			rdma_req->state = RDMA_REQUEST_STATE_COMPLETED;
3909 			/* +1 for the response wr */
3910 			rqpair->current_send_depth -= rdma_req->num_outstanding_data_wr + 1;
3911 			rdma_req->num_outstanding_data_wr = 0;
3912 
3913 			spdk_nvmf_rdma_request_process(rtransport, rdma_req);
3914 			break;
3915 		case RDMA_WR_TYPE_RECV:
3916 			/* rdma_recv->qpair will be invalid if using an SRQ.  In that case we have to get the qpair from the wc. */
3917 			rdma_recv = SPDK_CONTAINEROF(rdma_wr, struct spdk_nvmf_rdma_recv, rdma_wr);
3918 			if (rpoller->srq != NULL) {
3919 				rdma_recv->qpair = get_rdma_qpair_from_wc(rpoller, &wc[i]);
3920 				/* It is possible that there are still some completions for destroyed QP
3921 				 * associated with SRQ. We just ignore these late completions and re-post
3922 				 * receive WRs back to SRQ.
3923 				 */
3924 				if (spdk_unlikely(NULL == rdma_recv->qpair)) {
3925 					struct ibv_recv_wr *bad_wr;
3926 					int rc;
3927 
3928 					rdma_recv->wr.next = NULL;
3929 					rc = ibv_post_srq_recv(rpoller->srq,
3930 							       &rdma_recv->wr,
3931 							       &bad_wr);
3932 					if (rc) {
3933 						SPDK_ERRLOG("Failed to re-post recv WR to SRQ, err %d\n", rc);
3934 					}
3935 					continue;
3936 				}
3937 			}
3938 			rqpair = rdma_recv->qpair;
3939 
3940 			assert(rqpair != NULL);
3941 			if (!wc[i].status) {
3942 				assert(wc[i].opcode == IBV_WC_RECV);
3943 				if (rqpair->current_recv_depth >= rqpair->max_queue_depth) {
3944 					spdk_nvmf_rdma_start_disconnect(rqpair);
3945 					break;
3946 				}
3947 			}
3948 
3949 			rdma_recv->wr.next = NULL;
3950 			rqpair->current_recv_depth++;
3951 			rdma_recv->receive_tsc = poll_tsc;
3952 			rpoller->stat.requests++;
3953 			STAILQ_INSERT_TAIL(&rqpair->resources->incoming_queue, rdma_recv, link);
3954 			break;
3955 		case RDMA_WR_TYPE_DATA:
3956 			rdma_req = SPDK_CONTAINEROF(rdma_wr, struct spdk_nvmf_rdma_request, data.rdma_wr);
3957 			rqpair = SPDK_CONTAINEROF(rdma_req->req.qpair, struct spdk_nvmf_rdma_qpair, qpair);
3958 
3959 			assert(rdma_req->num_outstanding_data_wr > 0);
3960 
3961 			rqpair->current_send_depth--;
3962 			rdma_req->num_outstanding_data_wr--;
3963 			if (!wc[i].status) {
3964 				assert(wc[i].opcode == IBV_WC_RDMA_READ);
3965 				rqpair->current_read_depth--;
3966 				/* wait for all outstanding reads associated with the same rdma_req to complete before proceeding. */
3967 				if (rdma_req->num_outstanding_data_wr == 0) {
3968 					rdma_req->state = RDMA_REQUEST_STATE_READY_TO_EXECUTE;
3969 					spdk_nvmf_rdma_request_process(rtransport, rdma_req);
3970 				}
3971 			} else {
3972 				/* If the data transfer fails still force the queue into the error state,
3973 				 * if we were performing an RDMA_READ, we need to force the request into a
3974 				 * completed state since it wasn't linked to a send. However, in the RDMA_WRITE
3975 				 * case, we should wait for the SEND to complete. */
3976 				SPDK_ERRLOG("data=%p length=%u\n", rdma_req->req.data, rdma_req->req.length);
3977 				if (rdma_req->data.wr.opcode == IBV_WR_RDMA_READ) {
3978 					rqpair->current_read_depth--;
3979 					if (rdma_req->num_outstanding_data_wr == 0) {
3980 						rdma_req->state = RDMA_REQUEST_STATE_COMPLETED;
3981 					}
3982 				}
3983 			}
3984 			break;
3985 		default:
3986 			SPDK_ERRLOG("Received an unknown opcode on the CQ: %d\n", wc[i].opcode);
3987 			continue;
3988 		}
3989 
3990 		/* Handle error conditions */
3991 		if (wc[i].status) {
3992 			SPDK_DEBUGLOG(SPDK_LOG_RDMA, "CQ error on CQ %p, Request 0x%lu (%d): %s\n",
3993 				      rpoller->cq, wc[i].wr_id, wc[i].status, ibv_wc_status_str(wc[i].status));
3994 
3995 			error = true;
3996 
3997 			if (rqpair->qpair.state == SPDK_NVMF_QPAIR_ACTIVE) {
3998 				/* Disconnect the connection. */
3999 				spdk_nvmf_rdma_start_disconnect(rqpair);
4000 			} else {
4001 				nvmf_rdma_destroy_drained_qpair(rqpair);
4002 			}
4003 			continue;
4004 		}
4005 
4006 		spdk_nvmf_rdma_qpair_process_pending(rtransport, rqpair, false);
4007 
4008 		if (rqpair->qpair.state != SPDK_NVMF_QPAIR_ACTIVE) {
4009 			nvmf_rdma_destroy_drained_qpair(rqpair);
4010 		}
4011 	}
4012 
4013 	if (error == true) {
4014 		return -1;
4015 	}
4016 
4017 	/* submit outstanding work requests. */
4018 	_poller_submit_recvs(rtransport, rpoller);
4019 	_poller_submit_sends(rtransport, rpoller);
4020 
4021 	return count;
4022 }
4023 
4024 static int
4025 spdk_nvmf_rdma_poll_group_poll(struct spdk_nvmf_transport_poll_group *group)
4026 {
4027 	struct spdk_nvmf_rdma_transport *rtransport;
4028 	struct spdk_nvmf_rdma_poll_group *rgroup;
4029 	struct spdk_nvmf_rdma_poller	*rpoller;
4030 	int				count, rc;
4031 
4032 	rtransport = SPDK_CONTAINEROF(group->transport, struct spdk_nvmf_rdma_transport, transport);
4033 	rgroup = SPDK_CONTAINEROF(group, struct spdk_nvmf_rdma_poll_group, group);
4034 
4035 	count = 0;
4036 	TAILQ_FOREACH(rpoller, &rgroup->pollers, link) {
4037 		rc = spdk_nvmf_rdma_poller_poll(rtransport, rpoller);
4038 		if (rc < 0) {
4039 			return rc;
4040 		}
4041 		count += rc;
4042 	}
4043 
4044 	return count;
4045 }
4046 
4047 static int
4048 spdk_nvmf_rdma_trid_from_cm_id(struct rdma_cm_id *id,
4049 			       struct spdk_nvme_transport_id *trid,
4050 			       bool peer)
4051 {
4052 	struct sockaddr *saddr;
4053 	uint16_t port;
4054 
4055 	spdk_nvme_trid_populate_transport(trid, SPDK_NVME_TRANSPORT_RDMA);
4056 
4057 	if (peer) {
4058 		saddr = rdma_get_peer_addr(id);
4059 	} else {
4060 		saddr = rdma_get_local_addr(id);
4061 	}
4062 	switch (saddr->sa_family) {
4063 	case AF_INET: {
4064 		struct sockaddr_in *saddr_in = (struct sockaddr_in *)saddr;
4065 
4066 		trid->adrfam = SPDK_NVMF_ADRFAM_IPV4;
4067 		inet_ntop(AF_INET, &saddr_in->sin_addr,
4068 			  trid->traddr, sizeof(trid->traddr));
4069 		if (peer) {
4070 			port = ntohs(rdma_get_dst_port(id));
4071 		} else {
4072 			port = ntohs(rdma_get_src_port(id));
4073 		}
4074 		snprintf(trid->trsvcid, sizeof(trid->trsvcid), "%u", port);
4075 		break;
4076 	}
4077 	case AF_INET6: {
4078 		struct sockaddr_in6 *saddr_in = (struct sockaddr_in6 *)saddr;
4079 		trid->adrfam = SPDK_NVMF_ADRFAM_IPV6;
4080 		inet_ntop(AF_INET6, &saddr_in->sin6_addr,
4081 			  trid->traddr, sizeof(trid->traddr));
4082 		if (peer) {
4083 			port = ntohs(rdma_get_dst_port(id));
4084 		} else {
4085 			port = ntohs(rdma_get_src_port(id));
4086 		}
4087 		snprintf(trid->trsvcid, sizeof(trid->trsvcid), "%u", port);
4088 		break;
4089 	}
4090 	default:
4091 		return -1;
4092 
4093 	}
4094 
4095 	return 0;
4096 }
4097 
4098 static int
4099 spdk_nvmf_rdma_qpair_get_peer_trid(struct spdk_nvmf_qpair *qpair,
4100 				   struct spdk_nvme_transport_id *trid)
4101 {
4102 	struct spdk_nvmf_rdma_qpair	*rqpair;
4103 
4104 	rqpair = SPDK_CONTAINEROF(qpair, struct spdk_nvmf_rdma_qpair, qpair);
4105 
4106 	return spdk_nvmf_rdma_trid_from_cm_id(rqpair->cm_id, trid, true);
4107 }
4108 
4109 static int
4110 spdk_nvmf_rdma_qpair_get_local_trid(struct spdk_nvmf_qpair *qpair,
4111 				    struct spdk_nvme_transport_id *trid)
4112 {
4113 	struct spdk_nvmf_rdma_qpair	*rqpair;
4114 
4115 	rqpair = SPDK_CONTAINEROF(qpair, struct spdk_nvmf_rdma_qpair, qpair);
4116 
4117 	return spdk_nvmf_rdma_trid_from_cm_id(rqpair->cm_id, trid, false);
4118 }
4119 
4120 static int
4121 spdk_nvmf_rdma_qpair_get_listen_trid(struct spdk_nvmf_qpair *qpair,
4122 				     struct spdk_nvme_transport_id *trid)
4123 {
4124 	struct spdk_nvmf_rdma_qpair	*rqpair;
4125 
4126 	rqpair = SPDK_CONTAINEROF(qpair, struct spdk_nvmf_rdma_qpair, qpair);
4127 
4128 	return spdk_nvmf_rdma_trid_from_cm_id(rqpair->listen_id, trid, false);
4129 }
4130 
4131 void
4132 spdk_nvmf_rdma_init_hooks(struct spdk_nvme_rdma_hooks *hooks)
4133 {
4134 	g_nvmf_hooks = *hooks;
4135 }
4136 
4137 static int
4138 spdk_nvmf_rdma_poll_group_get_stat(struct spdk_nvmf_tgt *tgt,
4139 				   struct spdk_nvmf_transport_poll_group_stat **stat)
4140 {
4141 	struct spdk_io_channel *ch;
4142 	struct spdk_nvmf_poll_group *group;
4143 	struct spdk_nvmf_transport_poll_group *tgroup;
4144 	struct spdk_nvmf_rdma_poll_group *rgroup;
4145 	struct spdk_nvmf_rdma_poller *rpoller;
4146 	struct spdk_nvmf_rdma_device_stat *device_stat;
4147 	uint64_t num_devices = 0;
4148 
4149 	if (tgt == NULL || stat == NULL) {
4150 		return -EINVAL;
4151 	}
4152 
4153 	ch = spdk_get_io_channel(tgt);
4154 	group = spdk_io_channel_get_ctx(ch);;
4155 	spdk_put_io_channel(ch);
4156 	TAILQ_FOREACH(tgroup, &group->tgroups, link) {
4157 		if (SPDK_NVME_TRANSPORT_RDMA == tgroup->transport->ops->type) {
4158 			*stat = calloc(1, sizeof(struct spdk_nvmf_transport_poll_group_stat));
4159 			if (!*stat) {
4160 				SPDK_ERRLOG("Failed to allocate memory for NVMf RDMA statistics\n");
4161 				return -ENOMEM;
4162 			}
4163 			(*stat)->trtype = SPDK_NVME_TRANSPORT_RDMA;
4164 
4165 			rgroup = SPDK_CONTAINEROF(tgroup, struct spdk_nvmf_rdma_poll_group, group);
4166 			/* Count devices to allocate enough memory */
4167 			TAILQ_FOREACH(rpoller, &rgroup->pollers, link) {
4168 				++num_devices;
4169 			}
4170 			(*stat)->rdma.devices = calloc(num_devices, sizeof(struct spdk_nvmf_rdma_device_stat));
4171 			if (!(*stat)->rdma.devices) {
4172 				SPDK_ERRLOG("Failed to allocate NVMf RDMA devices statistics\n");
4173 				free(*stat);
4174 				return -ENOMEM;
4175 			}
4176 
4177 			(*stat)->rdma.pending_data_buffer = rgroup->stat.pending_data_buffer;
4178 			(*stat)->rdma.num_devices = num_devices;
4179 			num_devices = 0;
4180 			TAILQ_FOREACH(rpoller, &rgroup->pollers, link) {
4181 				device_stat = &(*stat)->rdma.devices[num_devices++];
4182 				device_stat->name = ibv_get_device_name(rpoller->device->context->device);
4183 				device_stat->polls = rpoller->stat.polls;
4184 				device_stat->completions = rpoller->stat.completions;
4185 				device_stat->requests = rpoller->stat.requests;
4186 				device_stat->request_latency = rpoller->stat.request_latency;
4187 				device_stat->pending_free_request = rpoller->stat.pending_free_request;
4188 				device_stat->pending_rdma_read = rpoller->stat.pending_rdma_read;
4189 				device_stat->pending_rdma_write = rpoller->stat.pending_rdma_write;
4190 			}
4191 			return 0;
4192 		}
4193 	}
4194 	return -ENOENT;
4195 }
4196 
4197 static void
4198 spdk_nvmf_rdma_poll_group_free_stat(struct spdk_nvmf_transport_poll_group_stat *stat)
4199 {
4200 	if (stat) {
4201 		free(stat->rdma.devices);
4202 	}
4203 	free(stat);
4204 }
4205 
4206 const struct spdk_nvmf_transport_ops spdk_nvmf_transport_rdma = {
4207 	.name = "RDMA",
4208 	.type = SPDK_NVME_TRANSPORT_RDMA,
4209 	.opts_init = spdk_nvmf_rdma_opts_init,
4210 	.create = spdk_nvmf_rdma_create,
4211 	.destroy = spdk_nvmf_rdma_destroy,
4212 
4213 	.listen = spdk_nvmf_rdma_listen,
4214 	.stop_listen = spdk_nvmf_rdma_stop_listen,
4215 	.accept = spdk_nvmf_rdma_accept,
4216 
4217 	.listener_discover = spdk_nvmf_rdma_discover,
4218 
4219 	.poll_group_create = spdk_nvmf_rdma_poll_group_create,
4220 	.get_optimal_poll_group = spdk_nvmf_rdma_get_optimal_poll_group,
4221 	.poll_group_destroy = spdk_nvmf_rdma_poll_group_destroy,
4222 	.poll_group_add = spdk_nvmf_rdma_poll_group_add,
4223 	.poll_group_poll = spdk_nvmf_rdma_poll_group_poll,
4224 
4225 	.req_free = spdk_nvmf_rdma_request_free,
4226 	.req_complete = spdk_nvmf_rdma_request_complete,
4227 
4228 	.qpair_fini = spdk_nvmf_rdma_close_qpair,
4229 	.qpair_get_peer_trid = spdk_nvmf_rdma_qpair_get_peer_trid,
4230 	.qpair_get_local_trid = spdk_nvmf_rdma_qpair_get_local_trid,
4231 	.qpair_get_listen_trid = spdk_nvmf_rdma_qpair_get_listen_trid,
4232 
4233 	.poll_group_get_stat = spdk_nvmf_rdma_poll_group_get_stat,
4234 	.poll_group_free_stat = spdk_nvmf_rdma_poll_group_free_stat,
4235 };
4236 
4237 SPDK_NVMF_TRANSPORT_REGISTER(rdma, &spdk_nvmf_transport_rdma);
4238 SPDK_LOG_REGISTER_COMPONENT("rdma", SPDK_LOG_RDMA)
4239