xref: /spdk/lib/nvmf/rdma.c (revision 8ab5b62c5a27e117e54afe54abc25a68ffd57f35)
1 /*-
2  *   BSD LICENSE
3  *
4  *   Copyright (c) Intel Corporation. All rights reserved.
5  *   Copyright (c) 2018 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 "nvmf_internal.h"
41 #include "transport.h"
42 
43 #include "spdk/config.h"
44 #include "spdk/assert.h"
45 #include "spdk/thread.h"
46 #include "spdk/nvmf.h"
47 #include "spdk/nvmf_spec.h"
48 #include "spdk/string.h"
49 #include "spdk/trace.h"
50 #include "spdk/util.h"
51 
52 #include "spdk_internal/log.h"
53 
54 struct spdk_nvme_rdma_hooks g_nvmf_hooks = {};
55 
56 /*
57  RDMA Connection Resource Defaults
58  */
59 #define NVMF_DEFAULT_TX_SGE		SPDK_NVMF_MAX_SGL_ENTRIES
60 #define NVMF_DEFAULT_RSP_SGE		1
61 #define NVMF_DEFAULT_RX_SGE		2
62 
63 /* The RDMA completion queue size */
64 #define DEFAULT_NVMF_RDMA_CQ_SIZE	4096
65 #define MAX_WR_PER_QP(queue_depth)	(queue_depth * 3 + 2)
66 
67 /* Timeout for destroying defunct rqpairs */
68 #define NVMF_RDMA_QPAIR_DESTROY_TIMEOUT_US	4000000
69 
70 /* The maximum number of buffers per request */
71 #define NVMF_REQ_MAX_BUFFERS	(SPDK_NVMF_MAX_SGL_ENTRIES * 2)
72 
73 static int g_spdk_nvmf_ibv_query_mask =
74 	IBV_QP_STATE |
75 	IBV_QP_PKEY_INDEX |
76 	IBV_QP_PORT |
77 	IBV_QP_ACCESS_FLAGS |
78 	IBV_QP_AV |
79 	IBV_QP_PATH_MTU |
80 	IBV_QP_DEST_QPN |
81 	IBV_QP_RQ_PSN |
82 	IBV_QP_MAX_DEST_RD_ATOMIC |
83 	IBV_QP_MIN_RNR_TIMER |
84 	IBV_QP_SQ_PSN |
85 	IBV_QP_TIMEOUT |
86 	IBV_QP_RETRY_CNT |
87 	IBV_QP_RNR_RETRY |
88 	IBV_QP_MAX_QP_RD_ATOMIC;
89 
90 enum spdk_nvmf_rdma_request_state {
91 	/* The request is not currently in use */
92 	RDMA_REQUEST_STATE_FREE = 0,
93 
94 	/* Initial state when request first received */
95 	RDMA_REQUEST_STATE_NEW,
96 
97 	/* The request is queued until a data buffer is available. */
98 	RDMA_REQUEST_STATE_NEED_BUFFER,
99 
100 	/* The request is waiting on RDMA queue depth availability
101 	 * to transfer data from the host to the controller.
102 	 */
103 	RDMA_REQUEST_STATE_DATA_TRANSFER_TO_CONTROLLER_PENDING,
104 
105 	/* The request is currently transferring data from the host to the controller. */
106 	RDMA_REQUEST_STATE_TRANSFERRING_HOST_TO_CONTROLLER,
107 
108 	/* The request is ready to execute at the block device */
109 	RDMA_REQUEST_STATE_READY_TO_EXECUTE,
110 
111 	/* The request is currently executing at the block device */
112 	RDMA_REQUEST_STATE_EXECUTING,
113 
114 	/* The request finished executing at the block device */
115 	RDMA_REQUEST_STATE_EXECUTED,
116 
117 	/* The request is waiting on RDMA queue depth availability
118 	 * to transfer data from the controller to the host.
119 	 */
120 	RDMA_REQUEST_STATE_DATA_TRANSFER_TO_HOST_PENDING,
121 
122 	/* The request is ready to send a completion */
123 	RDMA_REQUEST_STATE_READY_TO_COMPLETE,
124 
125 	/* The request is currently transferring data from the controller to the host. */
126 	RDMA_REQUEST_STATE_TRANSFERRING_CONTROLLER_TO_HOST,
127 
128 	/* The request currently has an outstanding completion without an
129 	 * associated data transfer.
130 	 */
131 	RDMA_REQUEST_STATE_COMPLETING,
132 
133 	/* The request completed and can be marked free. */
134 	RDMA_REQUEST_STATE_COMPLETED,
135 
136 	/* Terminator */
137 	RDMA_REQUEST_NUM_STATES,
138 };
139 
140 #define OBJECT_NVMF_RDMA_IO				0x40
141 
142 #define TRACE_GROUP_NVMF_RDMA				0x4
143 #define TRACE_RDMA_REQUEST_STATE_NEW					SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0x0)
144 #define TRACE_RDMA_REQUEST_STATE_NEED_BUFFER				SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0x1)
145 #define TRACE_RDMA_REQUEST_STATE_DATA_TRANSFER_TO_CONTROLLER_PENDING	SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0x2)
146 #define TRACE_RDMA_REQUEST_STATE_TRANSFERRING_HOST_TO_CONTROLLER	SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0x3)
147 #define TRACE_RDMA_REQUEST_STATE_READY_TO_EXECUTE			SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0x4)
148 #define TRACE_RDMA_REQUEST_STATE_EXECUTING				SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0x5)
149 #define TRACE_RDMA_REQUEST_STATE_EXECUTED				SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0x6)
150 #define TRACE_RDMA_REQUEST_STATE_DATA_TRANSFER_TO_HOST_PENDING		SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0x7)
151 #define TRACE_RDMA_REQUEST_STATE_READY_TO_COMPLETE			SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0x8)
152 #define TRACE_RDMA_REQUEST_STATE_TRANSFERRING_CONTROLLER_TO_HOST	SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0x9)
153 #define TRACE_RDMA_REQUEST_STATE_COMPLETING				SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0xA)
154 #define TRACE_RDMA_REQUEST_STATE_COMPLETED				SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0xB)
155 #define TRACE_RDMA_QP_CREATE						SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0xC)
156 #define TRACE_RDMA_IBV_ASYNC_EVENT					SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0xD)
157 #define TRACE_RDMA_CM_ASYNC_EVENT					SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0xE)
158 #define TRACE_RDMA_QP_STATE_CHANGE					SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0xF)
159 #define TRACE_RDMA_QP_DISCONNECT					SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0x10)
160 #define TRACE_RDMA_QP_DESTROY						SPDK_TPOINT_ID(TRACE_GROUP_NVMF_RDMA, 0x11)
161 
162 SPDK_TRACE_REGISTER_FN(nvmf_trace, "nvmf_rdma", TRACE_GROUP_NVMF_RDMA)
163 {
164 	spdk_trace_register_object(OBJECT_NVMF_RDMA_IO, 'r');
165 	spdk_trace_register_description("RDMA_REQ_NEW", TRACE_RDMA_REQUEST_STATE_NEW,
166 					OWNER_NONE, OBJECT_NVMF_RDMA_IO, 1, 1, "cmid:   ");
167 	spdk_trace_register_description("RDMA_REQ_NEED_BUFFER", TRACE_RDMA_REQUEST_STATE_NEED_BUFFER,
168 					OWNER_NONE, OBJECT_NVMF_RDMA_IO, 0, 1, "cmid:   ");
169 	spdk_trace_register_description("RDMA_REQ_TX_PENDING_C2H",
170 					TRACE_RDMA_REQUEST_STATE_DATA_TRANSFER_TO_HOST_PENDING,
171 					OWNER_NONE, OBJECT_NVMF_RDMA_IO, 0, 1, "cmid:   ");
172 	spdk_trace_register_description("RDMA_REQ_TX_PENDING_H2C",
173 					TRACE_RDMA_REQUEST_STATE_DATA_TRANSFER_TO_CONTROLLER_PENDING,
174 					OWNER_NONE, OBJECT_NVMF_RDMA_IO, 0, 1, "cmid:   ");
175 	spdk_trace_register_description("RDMA_REQ_TX_H2C",
176 					TRACE_RDMA_REQUEST_STATE_TRANSFERRING_HOST_TO_CONTROLLER,
177 					OWNER_NONE, OBJECT_NVMF_RDMA_IO, 0, 1, "cmid:   ");
178 	spdk_trace_register_description("RDMA_REQ_RDY_TO_EXECUTE",
179 					TRACE_RDMA_REQUEST_STATE_READY_TO_EXECUTE,
180 					OWNER_NONE, OBJECT_NVMF_RDMA_IO, 0, 1, "cmid:   ");
181 	spdk_trace_register_description("RDMA_REQ_EXECUTING",
182 					TRACE_RDMA_REQUEST_STATE_EXECUTING,
183 					OWNER_NONE, OBJECT_NVMF_RDMA_IO, 0, 1, "cmid:   ");
184 	spdk_trace_register_description("RDMA_REQ_EXECUTED",
185 					TRACE_RDMA_REQUEST_STATE_EXECUTED,
186 					OWNER_NONE, OBJECT_NVMF_RDMA_IO, 0, 1, "cmid:   ");
187 	spdk_trace_register_description("RDMA_REQ_RDY_TO_COMPL",
188 					TRACE_RDMA_REQUEST_STATE_READY_TO_COMPLETE,
189 					OWNER_NONE, OBJECT_NVMF_RDMA_IO, 0, 1, "cmid:   ");
190 	spdk_trace_register_description("RDMA_REQ_COMPLETING_C2H",
191 					TRACE_RDMA_REQUEST_STATE_TRANSFERRING_CONTROLLER_TO_HOST,
192 					OWNER_NONE, OBJECT_NVMF_RDMA_IO, 0, 1, "cmid:   ");
193 	spdk_trace_register_description("RDMA_REQ_COMPLETING",
194 					TRACE_RDMA_REQUEST_STATE_COMPLETING,
195 					OWNER_NONE, OBJECT_NVMF_RDMA_IO, 0, 1, "cmid:   ");
196 	spdk_trace_register_description("RDMA_REQ_COMPLETED",
197 					TRACE_RDMA_REQUEST_STATE_COMPLETED,
198 					OWNER_NONE, OBJECT_NVMF_RDMA_IO, 0, 1, "cmid:   ");
199 
200 	spdk_trace_register_description("RDMA_QP_CREATE", TRACE_RDMA_QP_CREATE,
201 					OWNER_NONE, OBJECT_NONE, 0, 0, "");
202 	spdk_trace_register_description("RDMA_IBV_ASYNC_EVENT", TRACE_RDMA_IBV_ASYNC_EVENT,
203 					OWNER_NONE, OBJECT_NONE, 0, 0, "type:   ");
204 	spdk_trace_register_description("RDMA_CM_ASYNC_EVENT", TRACE_RDMA_CM_ASYNC_EVENT,
205 					OWNER_NONE, OBJECT_NONE, 0, 0, "type:   ");
206 	spdk_trace_register_description("RDMA_QP_STATE_CHANGE", TRACE_RDMA_QP_STATE_CHANGE,
207 					OWNER_NONE, OBJECT_NONE, 0, 1, "state:  ");
208 	spdk_trace_register_description("RDMA_QP_DISCONNECT", TRACE_RDMA_QP_DISCONNECT,
209 					OWNER_NONE, OBJECT_NONE, 0, 0, "");
210 	spdk_trace_register_description("RDMA_QP_DESTROY", TRACE_RDMA_QP_DESTROY,
211 					OWNER_NONE, OBJECT_NONE, 0, 0, "");
212 }
213 
214 enum spdk_nvmf_rdma_wr_type {
215 	RDMA_WR_TYPE_RECV,
216 	RDMA_WR_TYPE_SEND,
217 	RDMA_WR_TYPE_DATA,
218 };
219 
220 struct spdk_nvmf_rdma_wr {
221 	enum spdk_nvmf_rdma_wr_type	type;
222 };
223 
224 /* This structure holds commands as they are received off the wire.
225  * It must be dynamically paired with a full request object
226  * (spdk_nvmf_rdma_request) to service a request. It is separate
227  * from the request because RDMA does not appear to order
228  * completions, so occasionally we'll get a new incoming
229  * command when there aren't any free request objects.
230  */
231 struct spdk_nvmf_rdma_recv {
232 	struct ibv_recv_wr			wr;
233 	struct ibv_sge				sgl[NVMF_DEFAULT_RX_SGE];
234 
235 	struct spdk_nvmf_rdma_qpair		*qpair;
236 
237 	/* In-capsule data buffer */
238 	uint8_t					*buf;
239 
240 	struct spdk_nvmf_rdma_wr		rdma_wr;
241 
242 	STAILQ_ENTRY(spdk_nvmf_rdma_recv)	link;
243 };
244 
245 struct spdk_nvmf_rdma_request_data {
246 	struct spdk_nvmf_rdma_wr	rdma_wr;
247 	struct ibv_send_wr		wr;
248 	struct ibv_sge			sgl[SPDK_NVMF_MAX_SGL_ENTRIES];
249 };
250 
251 struct spdk_nvmf_rdma_request {
252 	struct spdk_nvmf_request		req;
253 	bool					data_from_pool;
254 
255 	enum spdk_nvmf_rdma_request_state	state;
256 
257 	struct spdk_nvmf_rdma_recv		*recv;
258 
259 	struct {
260 		struct spdk_nvmf_rdma_wr	rdma_wr;
261 		struct	ibv_send_wr		wr;
262 		struct	ibv_sge			sgl[NVMF_DEFAULT_RSP_SGE];
263 	} rsp;
264 
265 	struct spdk_nvmf_rdma_request_data	data;
266 	void					*buffers[NVMF_REQ_MAX_BUFFERS];
267 
268 	uint32_t				num_outstanding_data_wr;
269 
270 	STAILQ_ENTRY(spdk_nvmf_rdma_request)	state_link;
271 };
272 
273 enum spdk_nvmf_rdma_qpair_disconnect_flags {
274 	RDMA_QP_DISCONNECTING		= 1,
275 	RDMA_QP_RECV_DRAINED		= 1 << 1,
276 	RDMA_QP_SEND_DRAINED		= 1 << 2
277 };
278 
279 struct spdk_nvmf_rdma_resource_opts {
280 	struct spdk_nvmf_rdma_qpair	*qpair;
281 	/* qp points either to an ibv_qp object or an ibv_srq object depending on the value of shared. */
282 	void				*qp;
283 	struct ibv_pd			*pd;
284 	uint32_t			max_queue_depth;
285 	uint32_t			in_capsule_data_size;
286 	bool				shared;
287 };
288 
289 struct spdk_nvmf_send_wr_list {
290 	struct ibv_send_wr	*first;
291 	struct ibv_send_wr	*last;
292 };
293 
294 struct spdk_nvmf_recv_wr_list {
295 	struct ibv_recv_wr	*first;
296 	struct ibv_recv_wr	*last;
297 };
298 
299 struct spdk_nvmf_rdma_resources {
300 	/* Array of size "max_queue_depth" containing RDMA requests. */
301 	struct spdk_nvmf_rdma_request		*reqs;
302 
303 	/* Array of size "max_queue_depth" containing RDMA recvs. */
304 	struct spdk_nvmf_rdma_recv		*recvs;
305 
306 	/* Array of size "max_queue_depth" containing 64 byte capsules
307 	 * used for receive.
308 	 */
309 	union nvmf_h2c_msg			*cmds;
310 	struct ibv_mr				*cmds_mr;
311 
312 	/* Array of size "max_queue_depth" containing 16 byte completions
313 	 * to be sent back to the user.
314 	 */
315 	union nvmf_c2h_msg			*cpls;
316 	struct ibv_mr				*cpls_mr;
317 
318 	/* Array of size "max_queue_depth * InCapsuleDataSize" containing
319 	 * buffers to be used for in capsule data.
320 	 */
321 	void					*bufs;
322 	struct ibv_mr				*bufs_mr;
323 
324 	/* The list of pending recvs to transfer */
325 	struct spdk_nvmf_recv_wr_list		recvs_to_post;
326 
327 	/* Receives that are waiting for a request object */
328 	STAILQ_HEAD(, spdk_nvmf_rdma_recv)	incoming_queue;
329 
330 	/* Queue to track free requests */
331 	STAILQ_HEAD(, spdk_nvmf_rdma_request)	free_queue;
332 };
333 
334 struct spdk_nvmf_rdma_qpair {
335 	struct spdk_nvmf_qpair			qpair;
336 
337 	struct spdk_nvmf_rdma_port		*port;
338 	struct spdk_nvmf_rdma_poller		*poller;
339 
340 	struct rdma_cm_id			*cm_id;
341 	struct ibv_srq				*srq;
342 	struct rdma_cm_id			*listen_id;
343 
344 	/* The maximum number of I/O outstanding on this connection at one time */
345 	uint16_t				max_queue_depth;
346 
347 	/* The maximum number of active RDMA READ and ATOMIC operations at one time */
348 	uint16_t				max_read_depth;
349 
350 	/* The maximum number of RDMA SEND operations at one time */
351 	uint32_t				max_send_depth;
352 
353 	/* The current number of outstanding WRs from this qpair's
354 	 * recv queue. Should not exceed device->attr.max_queue_depth.
355 	 */
356 	uint16_t				current_recv_depth;
357 
358 	/* The current number of active RDMA READ operations */
359 	uint16_t				current_read_depth;
360 
361 	/* The current number of posted WRs from this qpair's
362 	 * send queue. Should not exceed max_send_depth.
363 	 */
364 	uint32_t				current_send_depth;
365 
366 	/* The maximum number of SGEs per WR on the send queue */
367 	uint32_t				max_send_sge;
368 
369 	/* The maximum number of SGEs per WR on the recv queue */
370 	uint32_t				max_recv_sge;
371 
372 	/* The list of pending send requests for a transfer */
373 	struct spdk_nvmf_send_wr_list		sends_to_post;
374 
375 	struct spdk_nvmf_rdma_resources		*resources;
376 
377 	STAILQ_HEAD(, spdk_nvmf_rdma_request)	pending_rdma_read_queue;
378 
379 	STAILQ_HEAD(, spdk_nvmf_rdma_request)	pending_rdma_write_queue;
380 
381 	/* Number of requests not in the free state */
382 	uint32_t				qd;
383 
384 	TAILQ_ENTRY(spdk_nvmf_rdma_qpair)	link;
385 
386 	STAILQ_ENTRY(spdk_nvmf_rdma_qpair)	recv_link;
387 
388 	STAILQ_ENTRY(spdk_nvmf_rdma_qpair)	send_link;
389 
390 	/* IBV queue pair attributes: they are used to manage
391 	 * qp state and recover from errors.
392 	 */
393 	enum ibv_qp_state			ibv_state;
394 
395 	uint32_t				disconnect_flags;
396 
397 	/* Poller registered in case the qpair doesn't properly
398 	 * complete the qpair destruct process and becomes defunct.
399 	 */
400 
401 	struct spdk_poller			*destruct_poller;
402 
403 	/* There are several ways a disconnect can start on a qpair
404 	 * and they are not all mutually exclusive. It is important
405 	 * that we only initialize one of these paths.
406 	 */
407 	bool					disconnect_started;
408 	/* Lets us know that we have received the last_wqe event. */
409 	bool					last_wqe_reached;
410 };
411 
412 struct spdk_nvmf_rdma_poller {
413 	struct spdk_nvmf_rdma_device		*device;
414 	struct spdk_nvmf_rdma_poll_group	*group;
415 
416 	int					num_cqe;
417 	int					required_num_wr;
418 	struct ibv_cq				*cq;
419 
420 	/* The maximum number of I/O outstanding on the shared receive queue at one time */
421 	uint16_t				max_srq_depth;
422 
423 	/* Shared receive queue */
424 	struct ibv_srq				*srq;
425 
426 	struct spdk_nvmf_rdma_resources		*resources;
427 
428 	TAILQ_HEAD(, spdk_nvmf_rdma_qpair)	qpairs;
429 
430 	STAILQ_HEAD(, spdk_nvmf_rdma_qpair)	qpairs_pending_recv;
431 
432 	STAILQ_HEAD(, spdk_nvmf_rdma_qpair)	qpairs_pending_send;
433 
434 	TAILQ_ENTRY(spdk_nvmf_rdma_poller)	link;
435 };
436 
437 struct spdk_nvmf_rdma_poll_group {
438 	struct spdk_nvmf_transport_poll_group	group;
439 
440 	/* Requests that are waiting to obtain a data buffer */
441 	STAILQ_HEAD(, spdk_nvmf_rdma_request)	pending_data_buf_queue;
442 
443 	TAILQ_HEAD(, spdk_nvmf_rdma_poller)	pollers;
444 };
445 
446 /* Assuming rdma_cm uses just one protection domain per ibv_context. */
447 struct spdk_nvmf_rdma_device {
448 	struct ibv_device_attr			attr;
449 	struct ibv_context			*context;
450 
451 	struct spdk_mem_map			*map;
452 	struct ibv_pd				*pd;
453 
454 	TAILQ_ENTRY(spdk_nvmf_rdma_device)	link;
455 };
456 
457 struct spdk_nvmf_rdma_port {
458 	struct spdk_nvme_transport_id		trid;
459 	struct rdma_cm_id			*id;
460 	struct spdk_nvmf_rdma_device		*device;
461 	uint32_t				ref;
462 	TAILQ_ENTRY(spdk_nvmf_rdma_port)	link;
463 };
464 
465 struct spdk_nvmf_rdma_transport {
466 	struct spdk_nvmf_transport	transport;
467 
468 	struct rdma_event_channel	*event_channel;
469 
470 	struct spdk_mempool		*data_wr_pool;
471 
472 	pthread_mutex_t			lock;
473 
474 	/* fields used to poll RDMA/IB events */
475 	nfds_t			npoll_fds;
476 	struct pollfd		*poll_fds;
477 
478 	TAILQ_HEAD(, spdk_nvmf_rdma_device)	devices;
479 	TAILQ_HEAD(, spdk_nvmf_rdma_port)	ports;
480 };
481 
482 static inline int
483 spdk_nvmf_rdma_check_ibv_state(enum ibv_qp_state state)
484 {
485 	switch (state) {
486 	case IBV_QPS_RESET:
487 	case IBV_QPS_INIT:
488 	case IBV_QPS_RTR:
489 	case IBV_QPS_RTS:
490 	case IBV_QPS_SQD:
491 	case IBV_QPS_SQE:
492 	case IBV_QPS_ERR:
493 		return 0;
494 	default:
495 		return -1;
496 	}
497 }
498 
499 static enum ibv_qp_state
500 spdk_nvmf_rdma_update_ibv_state(struct spdk_nvmf_rdma_qpair *rqpair) {
501 	enum ibv_qp_state old_state, new_state;
502 	struct ibv_qp_attr qp_attr;
503 	struct ibv_qp_init_attr init_attr;
504 	int rc;
505 
506 	old_state = rqpair->ibv_state;
507 	rc = ibv_query_qp(rqpair->cm_id->qp, &qp_attr,
508 			  g_spdk_nvmf_ibv_query_mask, &init_attr);
509 
510 	if (rc)
511 	{
512 		SPDK_ERRLOG("Failed to get updated RDMA queue pair state!\n");
513 		return IBV_QPS_ERR + 1;
514 	}
515 
516 	new_state = qp_attr.qp_state;
517 	rqpair->ibv_state = new_state;
518 	qp_attr.ah_attr.port_num = qp_attr.port_num;
519 
520 	rc = spdk_nvmf_rdma_check_ibv_state(new_state);
521 	if (rc)
522 	{
523 		SPDK_ERRLOG("QP#%d: bad state updated: %u, maybe hardware issue\n", rqpair->qpair.qid, new_state);
524 		/*
525 		 * IBV_QPS_UNKNOWN undefined if lib version smaller than libibverbs-1.1.8
526 		 * IBV_QPS_UNKNOWN is the enum element after IBV_QPS_ERR
527 		 */
528 		return IBV_QPS_ERR + 1;
529 	}
530 
531 	if (old_state != new_state)
532 	{
533 		spdk_trace_record(TRACE_RDMA_QP_STATE_CHANGE, 0, 0,
534 				  (uintptr_t)rqpair->cm_id, new_state);
535 	}
536 	return new_state;
537 }
538 
539 static const char *str_ibv_qp_state[] = {
540 	"IBV_QPS_RESET",
541 	"IBV_QPS_INIT",
542 	"IBV_QPS_RTR",
543 	"IBV_QPS_RTS",
544 	"IBV_QPS_SQD",
545 	"IBV_QPS_SQE",
546 	"IBV_QPS_ERR",
547 	"IBV_QPS_UNKNOWN"
548 };
549 
550 static int
551 spdk_nvmf_rdma_set_ibv_state(struct spdk_nvmf_rdma_qpair *rqpair,
552 			     enum ibv_qp_state new_state)
553 {
554 	struct ibv_qp_attr qp_attr;
555 	struct ibv_qp_init_attr init_attr;
556 	int rc;
557 	enum ibv_qp_state state;
558 	static int attr_mask_rc[] = {
559 		[IBV_QPS_RESET] = IBV_QP_STATE,
560 		[IBV_QPS_INIT] = (IBV_QP_STATE |
561 				  IBV_QP_PKEY_INDEX |
562 				  IBV_QP_PORT |
563 				  IBV_QP_ACCESS_FLAGS),
564 		[IBV_QPS_RTR] = (IBV_QP_STATE |
565 				 IBV_QP_AV |
566 				 IBV_QP_PATH_MTU |
567 				 IBV_QP_DEST_QPN |
568 				 IBV_QP_RQ_PSN |
569 				 IBV_QP_MAX_DEST_RD_ATOMIC |
570 				 IBV_QP_MIN_RNR_TIMER),
571 		[IBV_QPS_RTS] = (IBV_QP_STATE |
572 				 IBV_QP_SQ_PSN |
573 				 IBV_QP_TIMEOUT |
574 				 IBV_QP_RETRY_CNT |
575 				 IBV_QP_RNR_RETRY |
576 				 IBV_QP_MAX_QP_RD_ATOMIC),
577 		[IBV_QPS_SQD] = IBV_QP_STATE,
578 		[IBV_QPS_SQE] = IBV_QP_STATE,
579 		[IBV_QPS_ERR] = IBV_QP_STATE,
580 	};
581 
582 	rc = spdk_nvmf_rdma_check_ibv_state(new_state);
583 	if (rc) {
584 		SPDK_ERRLOG("QP#%d: bad state requested: %u\n",
585 			    rqpair->qpair.qid, new_state);
586 		return rc;
587 	}
588 
589 	rc = ibv_query_qp(rqpair->cm_id->qp, &qp_attr,
590 			  g_spdk_nvmf_ibv_query_mask, &init_attr);
591 
592 	if (rc) {
593 		SPDK_ERRLOG("Failed to get updated RDMA queue pair state!\n");
594 		assert(false);
595 	}
596 
597 	qp_attr.cur_qp_state = rqpair->ibv_state;
598 	qp_attr.qp_state = new_state;
599 
600 	rc = ibv_modify_qp(rqpair->cm_id->qp, &qp_attr,
601 			   attr_mask_rc[new_state]);
602 
603 	if (rc) {
604 		SPDK_ERRLOG("QP#%d: failed to set state to: %s, %d (%s)\n",
605 			    rqpair->qpair.qid, str_ibv_qp_state[new_state], errno, strerror(errno));
606 		return rc;
607 	}
608 
609 	state = spdk_nvmf_rdma_update_ibv_state(rqpair);
610 
611 	if (state != new_state) {
612 		SPDK_ERRLOG("QP#%d: expected state: %s, actual state: %s\n",
613 			    rqpair->qpair.qid, str_ibv_qp_state[new_state],
614 			    str_ibv_qp_state[state]);
615 		return -1;
616 	}
617 	SPDK_DEBUGLOG(SPDK_LOG_RDMA, "IBV QP#%u changed to: %s\n", rqpair->qpair.qid,
618 		      str_ibv_qp_state[state]);
619 	return 0;
620 }
621 
622 static void
623 nvmf_rdma_request_free_data(struct spdk_nvmf_rdma_request *rdma_req,
624 			    struct spdk_nvmf_rdma_transport *rtransport)
625 {
626 	struct spdk_nvmf_rdma_request_data	*current_data_wr = NULL, *next_data_wr = NULL;
627 	struct ibv_send_wr			*send_wr;
628 	int					i;
629 
630 	rdma_req->num_outstanding_data_wr = 0;
631 	current_data_wr = &rdma_req->data;
632 	for (i = 0; i < current_data_wr->wr.num_sge; i++) {
633 		current_data_wr->wr.sg_list[i].addr = 0;
634 		current_data_wr->wr.sg_list[i].length = 0;
635 		current_data_wr->wr.sg_list[i].lkey = 0;
636 	}
637 	current_data_wr->wr.num_sge = 0;
638 
639 	send_wr = current_data_wr->wr.next;
640 	if (send_wr != NULL && send_wr != &rdma_req->rsp.wr) {
641 		next_data_wr = SPDK_CONTAINEROF(send_wr, struct spdk_nvmf_rdma_request_data, wr);
642 	}
643 	while (next_data_wr) {
644 		current_data_wr = next_data_wr;
645 		send_wr = current_data_wr->wr.next;
646 		if (send_wr != NULL && send_wr != &rdma_req->rsp.wr &&
647 		    send_wr->wr_id == current_data_wr->wr.wr_id) {
648 			next_data_wr = SPDK_CONTAINEROF(send_wr, struct spdk_nvmf_rdma_request_data, wr);
649 		} else {
650 			next_data_wr = NULL;
651 		}
652 
653 		for (i = 0; i < current_data_wr->wr.num_sge; i++) {
654 			current_data_wr->wr.sg_list[i].addr = 0;
655 			current_data_wr->wr.sg_list[i].length = 0;
656 			current_data_wr->wr.sg_list[i].lkey = 0;
657 		}
658 		current_data_wr->wr.num_sge = 0;
659 		spdk_mempool_put(rtransport->data_wr_pool, current_data_wr);
660 	}
661 }
662 
663 static void
664 nvmf_rdma_dump_request(struct spdk_nvmf_rdma_request *req)
665 {
666 	SPDK_ERRLOG("\t\tRequest Data From Pool: %d\n", req->data_from_pool);
667 	if (req->req.cmd) {
668 		SPDK_ERRLOG("\t\tRequest opcode: %d\n", req->req.cmd->nvmf_cmd.opcode);
669 	}
670 	if (req->recv) {
671 		SPDK_ERRLOG("\t\tRequest recv wr_id%lu\n", req->recv->wr.wr_id);
672 	}
673 }
674 
675 static void
676 nvmf_rdma_dump_qpair_contents(struct spdk_nvmf_rdma_qpair *rqpair)
677 {
678 	int i;
679 
680 	SPDK_ERRLOG("Dumping contents of queue pair (QID %d)\n", rqpair->qpair.qid);
681 	for (i = 0; i < rqpair->max_queue_depth; i++) {
682 		if (rqpair->resources->reqs[i].state != RDMA_REQUEST_STATE_FREE) {
683 			nvmf_rdma_dump_request(&rqpair->resources->reqs[i]);
684 		}
685 	}
686 }
687 
688 static void
689 nvmf_rdma_resources_destroy(struct spdk_nvmf_rdma_resources *resources)
690 {
691 	if (resources->cmds_mr) {
692 		ibv_dereg_mr(resources->cmds_mr);
693 	}
694 
695 	if (resources->cpls_mr) {
696 		ibv_dereg_mr(resources->cpls_mr);
697 	}
698 
699 	if (resources->bufs_mr) {
700 		ibv_dereg_mr(resources->bufs_mr);
701 	}
702 
703 	spdk_dma_free(resources->cmds);
704 	spdk_dma_free(resources->cpls);
705 	spdk_dma_free(resources->bufs);
706 	free(resources->reqs);
707 	free(resources->recvs);
708 	free(resources);
709 }
710 
711 
712 static struct spdk_nvmf_rdma_resources *
713 nvmf_rdma_resources_create(struct spdk_nvmf_rdma_resource_opts *opts)
714 {
715 	struct spdk_nvmf_rdma_resources	*resources;
716 	struct spdk_nvmf_rdma_request	*rdma_req;
717 	struct spdk_nvmf_rdma_recv	*rdma_recv;
718 	struct ibv_qp			*qp;
719 	struct ibv_srq			*srq;
720 	uint32_t			i;
721 	int				rc;
722 
723 	resources = calloc(1, sizeof(struct spdk_nvmf_rdma_resources));
724 	if (!resources) {
725 		SPDK_ERRLOG("Unable to allocate resources for receive queue.\n");
726 		return NULL;
727 	}
728 
729 	resources->reqs = calloc(opts->max_queue_depth, sizeof(*resources->reqs));
730 	resources->recvs = calloc(opts->max_queue_depth, sizeof(*resources->recvs));
731 	resources->cmds = spdk_dma_zmalloc(opts->max_queue_depth * sizeof(*resources->cmds),
732 					   0x1000, NULL);
733 	resources->cpls = spdk_dma_zmalloc(opts->max_queue_depth * sizeof(*resources->cpls),
734 					   0x1000, NULL);
735 
736 	if (opts->in_capsule_data_size > 0) {
737 		resources->bufs = spdk_dma_zmalloc(opts->max_queue_depth *
738 						   opts->in_capsule_data_size,
739 						   0x1000, NULL);
740 	}
741 
742 	if (!resources->reqs || !resources->recvs || !resources->cmds ||
743 	    !resources->cpls || (opts->in_capsule_data_size && !resources->bufs)) {
744 		SPDK_ERRLOG("Unable to allocate sufficient memory for RDMA queue.\n");
745 		goto cleanup;
746 	}
747 
748 	resources->cmds_mr = ibv_reg_mr(opts->pd, resources->cmds,
749 					opts->max_queue_depth * sizeof(*resources->cmds),
750 					IBV_ACCESS_LOCAL_WRITE);
751 	resources->cpls_mr = ibv_reg_mr(opts->pd, resources->cpls,
752 					opts->max_queue_depth * sizeof(*resources->cpls),
753 					0);
754 
755 	if (opts->in_capsule_data_size) {
756 		resources->bufs_mr = ibv_reg_mr(opts->pd, resources->bufs,
757 						opts->max_queue_depth *
758 						opts->in_capsule_data_size,
759 						IBV_ACCESS_LOCAL_WRITE | IBV_ACCESS_REMOTE_WRITE);
760 	}
761 
762 	if (!resources->cmds_mr || !resources->cpls_mr ||
763 	    (opts->in_capsule_data_size &&
764 	     !resources->bufs_mr)) {
765 		goto cleanup;
766 	}
767 	SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Command Array: %p Length: %lx LKey: %x\n",
768 		      resources->cmds, opts->max_queue_depth * sizeof(*resources->cmds),
769 		      resources->cmds_mr->lkey);
770 	SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Completion Array: %p Length: %lx LKey: %x\n",
771 		      resources->cpls, opts->max_queue_depth * sizeof(*resources->cpls),
772 		      resources->cpls_mr->lkey);
773 	if (resources->bufs && resources->bufs_mr) {
774 		SPDK_DEBUGLOG(SPDK_LOG_RDMA, "In Capsule Data Array: %p Length: %x LKey: %x\n",
775 			      resources->bufs, opts->max_queue_depth *
776 			      opts->in_capsule_data_size, resources->bufs_mr->lkey);
777 	}
778 
779 	/* Initialize queues */
780 	STAILQ_INIT(&resources->incoming_queue);
781 	STAILQ_INIT(&resources->free_queue);
782 
783 	for (i = 0; i < opts->max_queue_depth; i++) {
784 		struct ibv_recv_wr *bad_wr = NULL;
785 
786 		rdma_recv = &resources->recvs[i];
787 		rdma_recv->qpair = opts->qpair;
788 
789 		/* Set up memory to receive commands */
790 		if (resources->bufs) {
791 			rdma_recv->buf = (void *)((uintptr_t)resources->bufs + (i *
792 						  opts->in_capsule_data_size));
793 		}
794 
795 		rdma_recv->rdma_wr.type = RDMA_WR_TYPE_RECV;
796 
797 		rdma_recv->sgl[0].addr = (uintptr_t)&resources->cmds[i];
798 		rdma_recv->sgl[0].length = sizeof(resources->cmds[i]);
799 		rdma_recv->sgl[0].lkey = resources->cmds_mr->lkey;
800 		rdma_recv->wr.num_sge = 1;
801 
802 		if (rdma_recv->buf && resources->bufs_mr) {
803 			rdma_recv->sgl[1].addr = (uintptr_t)rdma_recv->buf;
804 			rdma_recv->sgl[1].length = opts->in_capsule_data_size;
805 			rdma_recv->sgl[1].lkey = resources->bufs_mr->lkey;
806 			rdma_recv->wr.num_sge++;
807 		}
808 
809 		rdma_recv->wr.wr_id = (uintptr_t)&rdma_recv->rdma_wr;
810 		rdma_recv->wr.sg_list = rdma_recv->sgl;
811 		if (opts->shared) {
812 			srq = (struct ibv_srq *)opts->qp;
813 			rc = ibv_post_srq_recv(srq, &rdma_recv->wr, &bad_wr);
814 		} else {
815 			qp = (struct ibv_qp *)opts->qp;
816 			rc = ibv_post_recv(qp, &rdma_recv->wr, &bad_wr);
817 		}
818 		if (rc) {
819 			goto cleanup;
820 		}
821 	}
822 
823 	for (i = 0; i < opts->max_queue_depth; i++) {
824 		rdma_req = &resources->reqs[i];
825 
826 		if (opts->qpair != NULL) {
827 			rdma_req->req.qpair = &opts->qpair->qpair;
828 		} else {
829 			rdma_req->req.qpair = NULL;
830 		}
831 		rdma_req->req.cmd = NULL;
832 
833 		/* Set up memory to send responses */
834 		rdma_req->req.rsp = &resources->cpls[i];
835 
836 		rdma_req->rsp.sgl[0].addr = (uintptr_t)&resources->cpls[i];
837 		rdma_req->rsp.sgl[0].length = sizeof(resources->cpls[i]);
838 		rdma_req->rsp.sgl[0].lkey = resources->cpls_mr->lkey;
839 
840 		rdma_req->rsp.rdma_wr.type = RDMA_WR_TYPE_SEND;
841 		rdma_req->rsp.wr.wr_id = (uintptr_t)&rdma_req->rsp.rdma_wr;
842 		rdma_req->rsp.wr.next = NULL;
843 		rdma_req->rsp.wr.opcode = IBV_WR_SEND;
844 		rdma_req->rsp.wr.send_flags = IBV_SEND_SIGNALED;
845 		rdma_req->rsp.wr.sg_list = rdma_req->rsp.sgl;
846 		rdma_req->rsp.wr.num_sge = SPDK_COUNTOF(rdma_req->rsp.sgl);
847 
848 		/* Set up memory for data buffers */
849 		rdma_req->data.rdma_wr.type = RDMA_WR_TYPE_DATA;
850 		rdma_req->data.wr.wr_id = (uintptr_t)&rdma_req->data.rdma_wr;
851 		rdma_req->data.wr.next = NULL;
852 		rdma_req->data.wr.send_flags = IBV_SEND_SIGNALED;
853 		rdma_req->data.wr.sg_list = rdma_req->data.sgl;
854 		rdma_req->data.wr.num_sge = SPDK_COUNTOF(rdma_req->data.sgl);
855 
856 		/* Initialize request state to FREE */
857 		rdma_req->state = RDMA_REQUEST_STATE_FREE;
858 		STAILQ_INSERT_TAIL(&resources->free_queue, rdma_req, state_link);
859 	}
860 
861 	return resources;
862 
863 cleanup:
864 	nvmf_rdma_resources_destroy(resources);
865 	return NULL;
866 }
867 
868 static void
869 spdk_nvmf_rdma_qpair_destroy(struct spdk_nvmf_rdma_qpair *rqpair)
870 {
871 	struct spdk_nvmf_rdma_recv	*rdma_recv, *recv_tmp;
872 	struct ibv_recv_wr		*bad_recv_wr = NULL;
873 	int				rc;
874 
875 	spdk_trace_record(TRACE_RDMA_QP_DESTROY, 0, 0, (uintptr_t)rqpair->cm_id, 0);
876 
877 	spdk_poller_unregister(&rqpair->destruct_poller);
878 
879 	if (rqpair->qd != 0) {
880 		if (rqpair->srq == NULL) {
881 			nvmf_rdma_dump_qpair_contents(rqpair);
882 		}
883 		SPDK_WARNLOG("Destroying qpair when queue depth is %d\n", rqpair->qd);
884 	}
885 
886 	if (rqpair->poller) {
887 		TAILQ_REMOVE(&rqpair->poller->qpairs, rqpair, link);
888 
889 		if (rqpair->srq != NULL && rqpair->resources != NULL) {
890 			/* Drop all received but unprocessed commands for this queue and return them to SRQ */
891 			STAILQ_FOREACH_SAFE(rdma_recv, &rqpair->resources->incoming_queue, link, recv_tmp) {
892 				if (rqpair == rdma_recv->qpair) {
893 					STAILQ_REMOVE_HEAD(&rqpair->resources->incoming_queue, link);
894 					rc = ibv_post_srq_recv(rqpair->srq, &rdma_recv->wr, &bad_recv_wr);
895 					if (rc) {
896 						SPDK_ERRLOG("Unable to re-post rx descriptor\n");
897 					}
898 				}
899 			}
900 		}
901 	}
902 
903 	if (rqpair->cm_id) {
904 		if (rqpair->cm_id->qp != NULL) {
905 			rdma_destroy_qp(rqpair->cm_id);
906 		}
907 		rdma_destroy_id(rqpair->cm_id);
908 
909 		if (rqpair->poller != NULL && rqpair->srq == NULL) {
910 			rqpair->poller->required_num_wr -= MAX_WR_PER_QP(rqpair->max_queue_depth);
911 		}
912 	}
913 
914 	if (rqpair->srq == NULL && rqpair->resources != NULL) {
915 		nvmf_rdma_resources_destroy(rqpair->resources);
916 	}
917 
918 	free(rqpair);
919 }
920 
921 static int
922 nvmf_rdma_resize_cq(struct spdk_nvmf_rdma_qpair *rqpair, struct spdk_nvmf_rdma_device *device)
923 {
924 	struct spdk_nvmf_rdma_poller	*rpoller;
925 	int				rc, num_cqe, required_num_wr;
926 
927 	/* Enlarge CQ size dynamically */
928 	rpoller = rqpair->poller;
929 	required_num_wr = rpoller->required_num_wr + MAX_WR_PER_QP(rqpair->max_queue_depth);
930 	num_cqe = rpoller->num_cqe;
931 	if (num_cqe < required_num_wr) {
932 		num_cqe = spdk_max(num_cqe * 2, required_num_wr);
933 		num_cqe = spdk_min(num_cqe, device->attr.max_cqe);
934 	}
935 
936 	if (rpoller->num_cqe != num_cqe) {
937 		if (required_num_wr > device->attr.max_cqe) {
938 			SPDK_ERRLOG("RDMA CQE requirement (%d) exceeds device max_cqe limitation (%d)\n",
939 				    required_num_wr, device->attr.max_cqe);
940 			return -1;
941 		}
942 
943 		SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Resize RDMA CQ from %d to %d\n", rpoller->num_cqe, num_cqe);
944 		rc = ibv_resize_cq(rpoller->cq, num_cqe);
945 		if (rc) {
946 			SPDK_ERRLOG("RDMA CQ resize failed: errno %d: %s\n", errno, spdk_strerror(errno));
947 			return -1;
948 		}
949 
950 		rpoller->num_cqe = num_cqe;
951 	}
952 
953 	rpoller->required_num_wr = required_num_wr;
954 	return 0;
955 }
956 
957 static int
958 spdk_nvmf_rdma_qpair_initialize(struct spdk_nvmf_qpair *qpair)
959 {
960 	struct spdk_nvmf_rdma_qpair		*rqpair;
961 	int					rc;
962 	struct spdk_nvmf_rdma_transport		*rtransport;
963 	struct spdk_nvmf_transport		*transport;
964 	struct spdk_nvmf_rdma_resource_opts	opts;
965 	struct spdk_nvmf_rdma_device		*device;
966 	struct ibv_qp_init_attr			ibv_init_attr;
967 
968 	rqpair = SPDK_CONTAINEROF(qpair, struct spdk_nvmf_rdma_qpair, qpair);
969 	device = rqpair->port->device;
970 
971 	memset(&ibv_init_attr, 0, sizeof(struct ibv_qp_init_attr));
972 	ibv_init_attr.qp_context	= rqpair;
973 	ibv_init_attr.qp_type		= IBV_QPT_RC;
974 	ibv_init_attr.send_cq		= rqpair->poller->cq;
975 	ibv_init_attr.recv_cq		= rqpair->poller->cq;
976 
977 	if (rqpair->srq) {
978 		ibv_init_attr.srq		= rqpair->srq;
979 	} else {
980 		ibv_init_attr.cap.max_recv_wr	= rqpair->max_queue_depth +
981 						  1; /* RECV operations + dummy drain WR */
982 	}
983 
984 	ibv_init_attr.cap.max_send_wr	= rqpair->max_queue_depth *
985 					  2 + 1; /* SEND, READ, and WRITE operations + dummy drain WR */
986 	ibv_init_attr.cap.max_send_sge	= spdk_min(device->attr.max_sge, NVMF_DEFAULT_TX_SGE);
987 	ibv_init_attr.cap.max_recv_sge	= spdk_min(device->attr.max_sge, NVMF_DEFAULT_RX_SGE);
988 
989 	if (rqpair->srq == NULL && nvmf_rdma_resize_cq(rqpair, device) < 0) {
990 		SPDK_ERRLOG("Failed to resize the completion queue. Cannot initialize qpair.\n");
991 		goto error;
992 	}
993 
994 	rc = rdma_create_qp(rqpair->cm_id, rqpair->port->device->pd, &ibv_init_attr);
995 	if (rc) {
996 		SPDK_ERRLOG("rdma_create_qp failed: errno %d: %s\n", errno, spdk_strerror(errno));
997 		goto error;
998 	}
999 
1000 	rqpair->max_send_depth = spdk_min((uint32_t)(rqpair->max_queue_depth * 2 + 1),
1001 					  ibv_init_attr.cap.max_send_wr);
1002 	rqpair->max_send_sge = spdk_min(NVMF_DEFAULT_TX_SGE, ibv_init_attr.cap.max_send_sge);
1003 	rqpair->max_recv_sge = spdk_min(NVMF_DEFAULT_RX_SGE, ibv_init_attr.cap.max_recv_sge);
1004 	spdk_trace_record(TRACE_RDMA_QP_CREATE, 0, 0, (uintptr_t)rqpair->cm_id, 0);
1005 	SPDK_DEBUGLOG(SPDK_LOG_RDMA, "New RDMA Connection: %p\n", qpair);
1006 
1007 	rqpair->sends_to_post.first = NULL;
1008 	rqpair->sends_to_post.last = NULL;
1009 
1010 	if (rqpair->poller->srq == NULL) {
1011 		rtransport = SPDK_CONTAINEROF(qpair->transport, struct spdk_nvmf_rdma_transport, transport);
1012 		transport = &rtransport->transport;
1013 
1014 		opts.qp = rqpair->cm_id->qp;
1015 		opts.pd = rqpair->cm_id->pd;
1016 		opts.qpair = rqpair;
1017 		opts.shared = false;
1018 		opts.max_queue_depth = rqpair->max_queue_depth;
1019 		opts.in_capsule_data_size = transport->opts.in_capsule_data_size;
1020 
1021 		rqpair->resources = nvmf_rdma_resources_create(&opts);
1022 
1023 		if (!rqpair->resources) {
1024 			SPDK_ERRLOG("Unable to allocate resources for receive queue.\n");
1025 			goto error;
1026 		}
1027 	} else {
1028 		rqpair->resources = rqpair->poller->resources;
1029 	}
1030 
1031 	rqpair->current_recv_depth = 0;
1032 	STAILQ_INIT(&rqpair->pending_rdma_read_queue);
1033 	STAILQ_INIT(&rqpair->pending_rdma_write_queue);
1034 
1035 	return 0;
1036 
1037 error:
1038 	rdma_destroy_id(rqpair->cm_id);
1039 	rqpair->cm_id = NULL;
1040 	spdk_nvmf_rdma_qpair_destroy(rqpair);
1041 	return -1;
1042 }
1043 
1044 /* Append the given recv wr structure to the resource structs outstanding recvs list. */
1045 /* This function accepts either a single wr or the first wr in a linked list. */
1046 static void
1047 nvmf_rdma_qpair_queue_recv_wrs(struct spdk_nvmf_rdma_qpair *rqpair, struct ibv_recv_wr *first)
1048 {
1049 	struct ibv_recv_wr *last;
1050 
1051 	last = first;
1052 	while (last->next != NULL) {
1053 		last = last->next;
1054 	}
1055 
1056 	if (rqpair->resources->recvs_to_post.first == NULL) {
1057 		rqpair->resources->recvs_to_post.first = first;
1058 		rqpair->resources->recvs_to_post.last = last;
1059 		if (rqpair->srq == NULL) {
1060 			STAILQ_INSERT_TAIL(&rqpair->poller->qpairs_pending_recv, rqpair, recv_link);
1061 		}
1062 	} else {
1063 		rqpair->resources->recvs_to_post.last->next = first;
1064 		rqpair->resources->recvs_to_post.last = last;
1065 	}
1066 }
1067 
1068 /* Append the given send wr structure to the qpair's outstanding sends list. */
1069 /* This function accepts either a single wr or the first wr in a linked list. */
1070 static void
1071 nvmf_rdma_qpair_queue_send_wrs(struct spdk_nvmf_rdma_qpair *rqpair, struct ibv_send_wr *first)
1072 {
1073 	struct ibv_send_wr *last;
1074 
1075 	last = first;
1076 	while (last->next != NULL) {
1077 		last = last->next;
1078 	}
1079 
1080 	if (rqpair->sends_to_post.first == NULL) {
1081 		rqpair->sends_to_post.first = first;
1082 		rqpair->sends_to_post.last = last;
1083 		STAILQ_INSERT_TAIL(&rqpair->poller->qpairs_pending_send, rqpair, send_link);
1084 	} else {
1085 		rqpair->sends_to_post.last->next = first;
1086 		rqpair->sends_to_post.last = last;
1087 	}
1088 }
1089 
1090 static int
1091 request_transfer_in(struct spdk_nvmf_request *req)
1092 {
1093 	struct spdk_nvmf_rdma_request	*rdma_req;
1094 	struct spdk_nvmf_qpair		*qpair;
1095 	struct spdk_nvmf_rdma_qpair	*rqpair;
1096 
1097 	qpair = req->qpair;
1098 	rdma_req = SPDK_CONTAINEROF(req, struct spdk_nvmf_rdma_request, req);
1099 	rqpair = SPDK_CONTAINEROF(qpair, struct spdk_nvmf_rdma_qpair, qpair);
1100 
1101 	assert(req->xfer == SPDK_NVME_DATA_HOST_TO_CONTROLLER);
1102 	assert(rdma_req != NULL);
1103 
1104 	nvmf_rdma_qpair_queue_send_wrs(rqpair, &rdma_req->data.wr);
1105 	rqpair->current_read_depth += rdma_req->num_outstanding_data_wr;
1106 	rqpair->current_send_depth += rdma_req->num_outstanding_data_wr;
1107 	return 0;
1108 }
1109 
1110 static int
1111 request_transfer_out(struct spdk_nvmf_request *req, int *data_posted)
1112 {
1113 	int				num_outstanding_data_wr = 0;
1114 	struct spdk_nvmf_rdma_request	*rdma_req;
1115 	struct spdk_nvmf_qpair		*qpair;
1116 	struct spdk_nvmf_rdma_qpair	*rqpair;
1117 	struct spdk_nvme_cpl		*rsp;
1118 	struct ibv_send_wr		*first = NULL;
1119 
1120 	*data_posted = 0;
1121 	qpair = req->qpair;
1122 	rsp = &req->rsp->nvme_cpl;
1123 	rdma_req = SPDK_CONTAINEROF(req, struct spdk_nvmf_rdma_request, req);
1124 	rqpair = SPDK_CONTAINEROF(qpair, struct spdk_nvmf_rdma_qpair, qpair);
1125 
1126 	/* Advance our sq_head pointer */
1127 	if (qpair->sq_head == qpair->sq_head_max) {
1128 		qpair->sq_head = 0;
1129 	} else {
1130 		qpair->sq_head++;
1131 	}
1132 	rsp->sqhd = qpair->sq_head;
1133 
1134 	/* queue the capsule for the recv buffer */
1135 	assert(rdma_req->recv != NULL);
1136 
1137 	nvmf_rdma_qpair_queue_recv_wrs(rqpair, &rdma_req->recv->wr);
1138 
1139 	rdma_req->recv = NULL;
1140 	assert(rqpair->current_recv_depth > 0);
1141 	rqpair->current_recv_depth--;
1142 
1143 	/* Build the response which consists of optional
1144 	 * RDMA WRITEs to transfer data, plus an RDMA SEND
1145 	 * containing the response.
1146 	 */
1147 	first = &rdma_req->rsp.wr;
1148 
1149 	if (rsp->status.sc == SPDK_NVME_SC_SUCCESS &&
1150 	    req->xfer == SPDK_NVME_DATA_CONTROLLER_TO_HOST) {
1151 		first = &rdma_req->data.wr;
1152 		*data_posted = 1;
1153 		num_outstanding_data_wr = rdma_req->num_outstanding_data_wr;
1154 	}
1155 	nvmf_rdma_qpair_queue_send_wrs(rqpair, first);
1156 	/* +1 for the rsp wr */
1157 	rqpair->current_send_depth += num_outstanding_data_wr + 1;
1158 
1159 	return 0;
1160 }
1161 
1162 static int
1163 spdk_nvmf_rdma_event_accept(struct rdma_cm_id *id, struct spdk_nvmf_rdma_qpair *rqpair)
1164 {
1165 	struct spdk_nvmf_rdma_accept_private_data	accept_data;
1166 	struct rdma_conn_param				ctrlr_event_data = {};
1167 	int						rc;
1168 
1169 	accept_data.recfmt = 0;
1170 	accept_data.crqsize = rqpair->max_queue_depth;
1171 
1172 	ctrlr_event_data.private_data = &accept_data;
1173 	ctrlr_event_data.private_data_len = sizeof(accept_data);
1174 	if (id->ps == RDMA_PS_TCP) {
1175 		ctrlr_event_data.responder_resources = 0; /* We accept 0 reads from the host */
1176 		ctrlr_event_data.initiator_depth = rqpair->max_read_depth;
1177 	}
1178 
1179 	/* Configure infinite retries for the initiator side qpair.
1180 	 * When using a shared receive queue on the target side,
1181 	 * we need to pass this value to the initiator to prevent the
1182 	 * initiator side NIC from completing SEND requests back to the
1183 	 * initiator with status rnr_retry_count_exceeded. */
1184 	if (rqpair->srq != NULL) {
1185 		ctrlr_event_data.rnr_retry_count = 0x7;
1186 	}
1187 
1188 	rc = rdma_accept(id, &ctrlr_event_data);
1189 	if (rc) {
1190 		SPDK_ERRLOG("Error %d on rdma_accept\n", errno);
1191 	} else {
1192 		SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Sent back the accept\n");
1193 	}
1194 
1195 	return rc;
1196 }
1197 
1198 static void
1199 spdk_nvmf_rdma_event_reject(struct rdma_cm_id *id, enum spdk_nvmf_rdma_transport_error error)
1200 {
1201 	struct spdk_nvmf_rdma_reject_private_data	rej_data;
1202 
1203 	rej_data.recfmt = 0;
1204 	rej_data.sts = error;
1205 
1206 	rdma_reject(id, &rej_data, sizeof(rej_data));
1207 }
1208 
1209 static int
1210 nvmf_rdma_connect(struct spdk_nvmf_transport *transport, struct rdma_cm_event *event,
1211 		  new_qpair_fn cb_fn)
1212 {
1213 	struct spdk_nvmf_rdma_transport *rtransport;
1214 	struct spdk_nvmf_rdma_qpair	*rqpair = NULL;
1215 	struct spdk_nvmf_rdma_port	*port;
1216 	struct rdma_conn_param		*rdma_param = NULL;
1217 	const struct spdk_nvmf_rdma_request_private_data *private_data = NULL;
1218 	uint16_t			max_queue_depth;
1219 	uint16_t			max_read_depth;
1220 
1221 	rtransport = SPDK_CONTAINEROF(transport, struct spdk_nvmf_rdma_transport, transport);
1222 
1223 	assert(event->id != NULL); /* Impossible. Can't even reject the connection. */
1224 	assert(event->id->verbs != NULL); /* Impossible. No way to handle this. */
1225 
1226 	rdma_param = &event->param.conn;
1227 	if (rdma_param->private_data == NULL ||
1228 	    rdma_param->private_data_len < sizeof(struct spdk_nvmf_rdma_request_private_data)) {
1229 		SPDK_ERRLOG("connect request: no private data provided\n");
1230 		spdk_nvmf_rdma_event_reject(event->id, SPDK_NVMF_RDMA_ERROR_INVALID_PRIVATE_DATA_LENGTH);
1231 		return -1;
1232 	}
1233 
1234 	private_data = rdma_param->private_data;
1235 	if (private_data->recfmt != 0) {
1236 		SPDK_ERRLOG("Received RDMA private data with RECFMT != 0\n");
1237 		spdk_nvmf_rdma_event_reject(event->id, SPDK_NVMF_RDMA_ERROR_INVALID_RECFMT);
1238 		return -1;
1239 	}
1240 
1241 	SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Connect Recv on fabric intf name %s, dev_name %s\n",
1242 		      event->id->verbs->device->name, event->id->verbs->device->dev_name);
1243 
1244 	port = event->listen_id->context;
1245 	SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Listen Id was %p with verbs %p. ListenAddr: %p\n",
1246 		      event->listen_id, event->listen_id->verbs, port);
1247 
1248 	/* Figure out the supported queue depth. This is a multi-step process
1249 	 * that takes into account hardware maximums, host provided values,
1250 	 * and our target's internal memory limits */
1251 
1252 	SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Calculating Queue Depth\n");
1253 
1254 	/* Start with the maximum queue depth allowed by the target */
1255 	max_queue_depth = rtransport->transport.opts.max_queue_depth;
1256 	max_read_depth = rtransport->transport.opts.max_queue_depth;
1257 	SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Target Max Queue Depth: %d\n",
1258 		      rtransport->transport.opts.max_queue_depth);
1259 
1260 	/* Next check the local NIC's hardware limitations */
1261 	SPDK_DEBUGLOG(SPDK_LOG_RDMA,
1262 		      "Local NIC Max Send/Recv Queue Depth: %d Max Read/Write Queue Depth: %d\n",
1263 		      port->device->attr.max_qp_wr, port->device->attr.max_qp_rd_atom);
1264 	max_queue_depth = spdk_min(max_queue_depth, port->device->attr.max_qp_wr);
1265 	max_read_depth = spdk_min(max_read_depth, port->device->attr.max_qp_init_rd_atom);
1266 
1267 	/* Next check the remote NIC's hardware limitations */
1268 	SPDK_DEBUGLOG(SPDK_LOG_RDMA,
1269 		      "Host (Initiator) NIC Max Incoming RDMA R/W operations: %d Max Outgoing RDMA R/W operations: %d\n",
1270 		      rdma_param->initiator_depth, rdma_param->responder_resources);
1271 	if (rdma_param->initiator_depth > 0) {
1272 		max_read_depth = spdk_min(max_read_depth, rdma_param->initiator_depth);
1273 	}
1274 
1275 	/* Finally check for the host software requested values, which are
1276 	 * optional. */
1277 	if (rdma_param->private_data != NULL &&
1278 	    rdma_param->private_data_len >= sizeof(struct spdk_nvmf_rdma_request_private_data)) {
1279 		SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Host Receive Queue Size: %d\n", private_data->hrqsize);
1280 		SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Host Send Queue Size: %d\n", private_data->hsqsize);
1281 		max_queue_depth = spdk_min(max_queue_depth, private_data->hrqsize);
1282 		max_queue_depth = spdk_min(max_queue_depth, private_data->hsqsize + 1);
1283 	}
1284 
1285 	SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Final Negotiated Queue Depth: %d R/W Depth: %d\n",
1286 		      max_queue_depth, max_read_depth);
1287 
1288 	rqpair = calloc(1, sizeof(struct spdk_nvmf_rdma_qpair));
1289 	if (rqpair == NULL) {
1290 		SPDK_ERRLOG("Could not allocate new connection.\n");
1291 		spdk_nvmf_rdma_event_reject(event->id, SPDK_NVMF_RDMA_ERROR_NO_RESOURCES);
1292 		return -1;
1293 	}
1294 
1295 	rqpair->port = port;
1296 	rqpair->max_queue_depth = max_queue_depth;
1297 	rqpair->max_read_depth = max_read_depth;
1298 	rqpair->cm_id = event->id;
1299 	rqpair->listen_id = event->listen_id;
1300 	rqpair->qpair.transport = transport;
1301 
1302 	event->id->context = &rqpair->qpair;
1303 
1304 	cb_fn(&rqpair->qpair);
1305 
1306 	return 0;
1307 }
1308 
1309 static int
1310 spdk_nvmf_rdma_mem_notify(void *cb_ctx, struct spdk_mem_map *map,
1311 			  enum spdk_mem_map_notify_action action,
1312 			  void *vaddr, size_t size)
1313 {
1314 	struct ibv_pd *pd = cb_ctx;
1315 	struct ibv_mr *mr;
1316 
1317 	switch (action) {
1318 	case SPDK_MEM_MAP_NOTIFY_REGISTER:
1319 		if (!g_nvmf_hooks.get_rkey) {
1320 			mr = ibv_reg_mr(pd, vaddr, size,
1321 					IBV_ACCESS_LOCAL_WRITE |
1322 					IBV_ACCESS_REMOTE_READ |
1323 					IBV_ACCESS_REMOTE_WRITE);
1324 			if (mr == NULL) {
1325 				SPDK_ERRLOG("ibv_reg_mr() failed\n");
1326 				return -1;
1327 			} else {
1328 				spdk_mem_map_set_translation(map, (uint64_t)vaddr, size, (uint64_t)mr);
1329 			}
1330 		} else {
1331 			spdk_mem_map_set_translation(map, (uint64_t)vaddr, size,
1332 						     g_nvmf_hooks.get_rkey(pd, vaddr, size));
1333 		}
1334 		break;
1335 	case SPDK_MEM_MAP_NOTIFY_UNREGISTER:
1336 		if (!g_nvmf_hooks.get_rkey) {
1337 			mr = (struct ibv_mr *)spdk_mem_map_translate(map, (uint64_t)vaddr, NULL);
1338 			spdk_mem_map_clear_translation(map, (uint64_t)vaddr, size);
1339 			if (mr) {
1340 				ibv_dereg_mr(mr);
1341 			}
1342 		}
1343 		break;
1344 	}
1345 
1346 	return 0;
1347 }
1348 
1349 static int
1350 spdk_nvmf_rdma_check_contiguous_entries(uint64_t addr_1, uint64_t addr_2)
1351 {
1352 	/* Two contiguous mappings will point to the same address which is the start of the RDMA MR. */
1353 	return addr_1 == addr_2;
1354 }
1355 
1356 static void
1357 spdk_nvmf_rdma_request_free_buffers(struct spdk_nvmf_rdma_request *rdma_req,
1358 				    struct spdk_nvmf_transport_poll_group *group, struct spdk_nvmf_transport *transport,
1359 				    uint32_t num_buffers)
1360 {
1361 	uint32_t i;
1362 
1363 	for (i = 0; i < num_buffers; i++) {
1364 		if (group->buf_cache_count < group->buf_cache_size) {
1365 			STAILQ_INSERT_HEAD(&group->buf_cache,
1366 					   (struct spdk_nvmf_transport_pg_cache_buf *)rdma_req->buffers[i], link);
1367 			group->buf_cache_count++;
1368 		} else {
1369 			spdk_mempool_put(transport->data_buf_pool, rdma_req->buffers[i]);
1370 		}
1371 		rdma_req->req.iov[i].iov_base = NULL;
1372 		rdma_req->buffers[i] = NULL;
1373 		rdma_req->req.iov[i].iov_len = 0;
1374 
1375 	}
1376 	rdma_req->data_from_pool = false;
1377 }
1378 
1379 static int
1380 nvmf_rdma_request_get_buffers(struct spdk_nvmf_rdma_request *rdma_req,
1381 			      struct spdk_nvmf_transport_poll_group *group, struct spdk_nvmf_transport *transport,
1382 			      uint32_t num_buffers)
1383 {
1384 	uint32_t i = 0;
1385 
1386 	while (i < num_buffers) {
1387 		if (!(STAILQ_EMPTY(&group->buf_cache))) {
1388 			group->buf_cache_count--;
1389 			rdma_req->buffers[i] = STAILQ_FIRST(&group->buf_cache);
1390 			STAILQ_REMOVE_HEAD(&group->buf_cache, link);
1391 			assert(rdma_req->buffers[i] != NULL);
1392 			i++;
1393 		} else {
1394 			if (spdk_mempool_get_bulk(transport->data_buf_pool, &rdma_req->buffers[i], num_buffers - i)) {
1395 				goto err_exit;
1396 			}
1397 			i += num_buffers - i;
1398 		}
1399 	}
1400 
1401 	return 0;
1402 
1403 err_exit:
1404 	spdk_nvmf_rdma_request_free_buffers(rdma_req, group, transport, i);
1405 	return -ENOMEM;
1406 }
1407 
1408 typedef enum spdk_nvme_data_transfer spdk_nvme_data_transfer_t;
1409 
1410 static spdk_nvme_data_transfer_t
1411 spdk_nvmf_rdma_request_get_xfer(struct spdk_nvmf_rdma_request *rdma_req)
1412 {
1413 	enum spdk_nvme_data_transfer xfer;
1414 	struct spdk_nvme_cmd *cmd = &rdma_req->req.cmd->nvme_cmd;
1415 	struct spdk_nvme_sgl_descriptor *sgl = &cmd->dptr.sgl1;
1416 
1417 #ifdef SPDK_CONFIG_RDMA_SEND_WITH_INVAL
1418 	rdma_req->rsp.wr.opcode = IBV_WR_SEND;
1419 	rdma_req->rsp.wr.imm_data = 0;
1420 #endif
1421 
1422 	/* Figure out data transfer direction */
1423 	if (cmd->opc == SPDK_NVME_OPC_FABRIC) {
1424 		xfer = spdk_nvme_opc_get_data_transfer(rdma_req->req.cmd->nvmf_cmd.fctype);
1425 	} else {
1426 		xfer = spdk_nvme_opc_get_data_transfer(cmd->opc);
1427 
1428 		/* Some admin commands are special cases */
1429 		if ((rdma_req->req.qpair->qid == 0) &&
1430 		    ((cmd->opc == SPDK_NVME_OPC_GET_FEATURES) ||
1431 		     (cmd->opc == SPDK_NVME_OPC_SET_FEATURES))) {
1432 			switch (cmd->cdw10 & 0xff) {
1433 			case SPDK_NVME_FEAT_LBA_RANGE_TYPE:
1434 			case SPDK_NVME_FEAT_AUTONOMOUS_POWER_STATE_TRANSITION:
1435 			case SPDK_NVME_FEAT_HOST_IDENTIFIER:
1436 				break;
1437 			default:
1438 				xfer = SPDK_NVME_DATA_NONE;
1439 			}
1440 		}
1441 	}
1442 
1443 	if (xfer == SPDK_NVME_DATA_NONE) {
1444 		return xfer;
1445 	}
1446 
1447 	/* Even for commands that may transfer data, they could have specified 0 length.
1448 	 * We want those to show up with xfer SPDK_NVME_DATA_NONE.
1449 	 */
1450 	switch (sgl->generic.type) {
1451 	case SPDK_NVME_SGL_TYPE_DATA_BLOCK:
1452 	case SPDK_NVME_SGL_TYPE_BIT_BUCKET:
1453 	case SPDK_NVME_SGL_TYPE_SEGMENT:
1454 	case SPDK_NVME_SGL_TYPE_LAST_SEGMENT:
1455 	case SPDK_NVME_SGL_TYPE_TRANSPORT_DATA_BLOCK:
1456 		if (sgl->unkeyed.length == 0) {
1457 			xfer = SPDK_NVME_DATA_NONE;
1458 		}
1459 		break;
1460 	case SPDK_NVME_SGL_TYPE_KEYED_DATA_BLOCK:
1461 		if (sgl->keyed.length == 0) {
1462 			xfer = SPDK_NVME_DATA_NONE;
1463 		}
1464 		break;
1465 	}
1466 
1467 	return xfer;
1468 }
1469 
1470 static int
1471 nvmf_request_alloc_wrs(struct spdk_nvmf_rdma_transport *rtransport,
1472 		       struct spdk_nvmf_rdma_request *rdma_req,
1473 		       uint32_t num_sgl_descriptors)
1474 {
1475 	struct spdk_nvmf_rdma_request_data	*work_requests[SPDK_NVMF_MAX_SGL_ENTRIES];
1476 	struct spdk_nvmf_rdma_request_data	*current_data_wr;
1477 	uint32_t				i;
1478 
1479 	if (spdk_mempool_get_bulk(rtransport->data_wr_pool, (void **)work_requests, num_sgl_descriptors)) {
1480 		return -ENOMEM;
1481 	}
1482 
1483 	current_data_wr = &rdma_req->data;
1484 
1485 	for (i = 0; i < num_sgl_descriptors; i++) {
1486 		if (rdma_req->req.xfer == SPDK_NVME_DATA_CONTROLLER_TO_HOST) {
1487 			current_data_wr->wr.opcode = IBV_WR_RDMA_WRITE;
1488 		} else if (rdma_req->req.xfer == SPDK_NVME_DATA_HOST_TO_CONTROLLER) {
1489 			current_data_wr->wr.opcode = IBV_WR_RDMA_READ;
1490 		} else {
1491 			assert(false);
1492 		}
1493 		work_requests[i]->wr.send_flags = IBV_SEND_SIGNALED;
1494 		work_requests[i]->wr.sg_list = work_requests[i]->sgl;
1495 		work_requests[i]->wr.wr_id = rdma_req->data.wr.wr_id;
1496 		current_data_wr->wr.next = &work_requests[i]->wr;
1497 		current_data_wr = work_requests[i];
1498 	}
1499 
1500 	if (rdma_req->req.xfer == SPDK_NVME_DATA_CONTROLLER_TO_HOST) {
1501 		current_data_wr->wr.opcode = IBV_WR_RDMA_WRITE;
1502 		current_data_wr->wr.next = &rdma_req->rsp.wr;
1503 	} else if (rdma_req->req.xfer == SPDK_NVME_DATA_HOST_TO_CONTROLLER) {
1504 		current_data_wr->wr.opcode = IBV_WR_RDMA_READ;
1505 		current_data_wr->wr.next = NULL;
1506 	}
1507 	return 0;
1508 }
1509 
1510 static int
1511 nvmf_rdma_fill_buffers(struct spdk_nvmf_rdma_transport *rtransport,
1512 		       struct spdk_nvmf_rdma_poll_group *rgroup,
1513 		       struct spdk_nvmf_rdma_device *device,
1514 		       struct spdk_nvmf_rdma_request *rdma_req,
1515 		       struct ibv_send_wr *wr,
1516 		       uint32_t length)
1517 {
1518 	uint64_t	translation_len;
1519 	uint32_t	remaining_length = length;
1520 	uint32_t	iovcnt;
1521 	uint32_t	i = 0;
1522 
1523 
1524 	while (remaining_length) {
1525 		iovcnt = rdma_req->req.iovcnt;
1526 		rdma_req->req.iov[iovcnt].iov_base = (void *)((uintptr_t)(rdma_req->buffers[iovcnt] +
1527 						     NVMF_DATA_BUFFER_MASK) &
1528 						     ~NVMF_DATA_BUFFER_MASK);
1529 		rdma_req->req.iov[iovcnt].iov_len  = spdk_min(remaining_length,
1530 						     rtransport->transport.opts.io_unit_size);
1531 		rdma_req->req.iovcnt++;
1532 		wr->sg_list[i].addr = (uintptr_t)(rdma_req->req.iov[iovcnt].iov_base);
1533 		wr->sg_list[i].length = rdma_req->req.iov[iovcnt].iov_len;
1534 		translation_len = rdma_req->req.iov[iovcnt].iov_len;
1535 
1536 		if (!g_nvmf_hooks.get_rkey) {
1537 			wr->sg_list[i].lkey = ((struct ibv_mr *)spdk_mem_map_translate(device->map,
1538 					       (uint64_t)rdma_req->buffers[iovcnt], &translation_len))->lkey;
1539 		} else {
1540 			wr->sg_list[i].lkey = spdk_mem_map_translate(device->map,
1541 					      (uint64_t)rdma_req->buffers[iovcnt], &translation_len);
1542 		}
1543 
1544 		remaining_length -= rdma_req->req.iov[iovcnt].iov_len;
1545 
1546 		if (translation_len < rdma_req->req.iov[iovcnt].iov_len) {
1547 			SPDK_ERRLOG("Data buffer split over multiple RDMA Memory Regions\n");
1548 			return -EINVAL;
1549 		}
1550 		i++;
1551 	}
1552 	wr->num_sge = i;
1553 
1554 	return 0;
1555 }
1556 
1557 static int
1558 spdk_nvmf_rdma_request_fill_iovs(struct spdk_nvmf_rdma_transport *rtransport,
1559 				 struct spdk_nvmf_rdma_device *device,
1560 				 struct spdk_nvmf_rdma_request *rdma_req)
1561 {
1562 	struct spdk_nvmf_rdma_qpair		*rqpair;
1563 	struct spdk_nvmf_rdma_poll_group	*rgroup;
1564 	uint32_t				num_buffers;
1565 	uint32_t				i = 0;
1566 	int					rc = 0;
1567 
1568 	rqpair = SPDK_CONTAINEROF(rdma_req->req.qpair, struct spdk_nvmf_rdma_qpair, qpair);
1569 	rgroup = rqpair->poller->group;
1570 	rdma_req->req.iovcnt = 0;
1571 
1572 	num_buffers = rdma_req->req.length / rtransport->transport.opts.io_unit_size;
1573 	if (rdma_req->req.length % rtransport->transport.opts.io_unit_size) {
1574 		num_buffers++;
1575 	}
1576 
1577 	if (nvmf_rdma_request_get_buffers(rdma_req, &rgroup->group, &rtransport->transport, num_buffers)) {
1578 		return -ENOMEM;
1579 	}
1580 
1581 	rdma_req->req.iovcnt = 0;
1582 
1583 	rc = nvmf_rdma_fill_buffers(rtransport, rgroup, device, rdma_req, &rdma_req->data.wr,
1584 				    rdma_req->req.length);
1585 	if (rc != 0) {
1586 		goto err_exit;
1587 	}
1588 
1589 	assert(rdma_req->req.iovcnt <= rqpair->max_send_sge);
1590 
1591 	rdma_req->data_from_pool = true;
1592 
1593 	return rc;
1594 
1595 err_exit:
1596 	spdk_nvmf_rdma_request_free_buffers(rdma_req, &rgroup->group, &rtransport->transport, num_buffers);
1597 	while (i) {
1598 		i--;
1599 		rdma_req->data.wr.sg_list[i].addr = 0;
1600 		rdma_req->data.wr.sg_list[i].length = 0;
1601 		rdma_req->data.wr.sg_list[i].lkey = 0;
1602 	}
1603 	rdma_req->req.iovcnt = 0;
1604 	return rc;
1605 }
1606 
1607 static int
1608 nvmf_rdma_request_fill_iovs_multi_sgl(struct spdk_nvmf_rdma_transport *rtransport,
1609 				      struct spdk_nvmf_rdma_device *device,
1610 				      struct spdk_nvmf_rdma_request *rdma_req)
1611 {
1612 	struct spdk_nvmf_rdma_qpair		*rqpair;
1613 	struct spdk_nvmf_rdma_poll_group	*rgroup;
1614 	struct ibv_send_wr			*current_wr;
1615 	struct spdk_nvmf_request		*req = &rdma_req->req;
1616 	struct spdk_nvme_sgl_descriptor		*inline_segment, *desc;
1617 	uint32_t				num_sgl_descriptors;
1618 	uint32_t				num_buffers = 0;
1619 	uint32_t				i;
1620 	int					rc;
1621 
1622 	rqpair = SPDK_CONTAINEROF(rdma_req->req.qpair, struct spdk_nvmf_rdma_qpair, qpair);
1623 	rgroup = rqpair->poller->group;
1624 
1625 	inline_segment = &req->cmd->nvme_cmd.dptr.sgl1;
1626 	assert(inline_segment->generic.type == SPDK_NVME_SGL_TYPE_LAST_SEGMENT);
1627 	assert(inline_segment->unkeyed.subtype == SPDK_NVME_SGL_SUBTYPE_OFFSET);
1628 
1629 	num_sgl_descriptors = inline_segment->unkeyed.length / sizeof(struct spdk_nvme_sgl_descriptor);
1630 	assert(num_sgl_descriptors <= SPDK_NVMF_MAX_SGL_ENTRIES);
1631 	desc = (struct spdk_nvme_sgl_descriptor *)rdma_req->recv->buf + inline_segment->address;
1632 
1633 	for (i = 0; i < num_sgl_descriptors; i++) {
1634 		num_buffers += desc->keyed.length / rtransport->transport.opts.io_unit_size;
1635 		if (desc->keyed.length % rtransport->transport.opts.io_unit_size) {
1636 			num_buffers++;
1637 		}
1638 		desc++;
1639 	}
1640 	/* If the number of buffers is too large, then we know the I/O is larger than allowed. Fail it. */
1641 	if (num_buffers > NVMF_REQ_MAX_BUFFERS) {
1642 		return -EINVAL;
1643 	}
1644 	if (nvmf_rdma_request_get_buffers(rdma_req, &rgroup->group, &rtransport->transport,
1645 					  num_buffers) != 0) {
1646 		return -ENOMEM;
1647 	}
1648 
1649 	if (nvmf_request_alloc_wrs(rtransport, rdma_req, num_sgl_descriptors - 1) != 0) {
1650 		spdk_nvmf_rdma_request_free_buffers(rdma_req, &rgroup->group, &rtransport->transport, num_buffers);
1651 		return -ENOMEM;
1652 	}
1653 
1654 	/* The first WR must always be the embedded data WR. This is how we unwind them later. */
1655 	current_wr = &rdma_req->data.wr;
1656 
1657 	req->iovcnt = 0;
1658 	desc = (struct spdk_nvme_sgl_descriptor *)rdma_req->recv->buf + inline_segment->address;
1659 	for (i = 0; i < num_sgl_descriptors; i++) {
1660 		/* The descriptors must be keyed data block descriptors with an address, not an offset. */
1661 		if (spdk_unlikely(desc->generic.type != SPDK_NVME_SGL_TYPE_KEYED_DATA_BLOCK ||
1662 				  desc->keyed.subtype != SPDK_NVME_SGL_SUBTYPE_ADDRESS)) {
1663 			rc = -EINVAL;
1664 			goto err_exit;
1665 		}
1666 
1667 		current_wr->num_sge = 0;
1668 		req->length += desc->keyed.length;
1669 
1670 		rc = nvmf_rdma_fill_buffers(rtransport, rgroup, device, rdma_req, current_wr,
1671 					    desc->keyed.length);
1672 		if (rc != 0) {
1673 			rc = -ENOMEM;
1674 			goto err_exit;
1675 		}
1676 
1677 		current_wr->wr.rdma.rkey = desc->keyed.key;
1678 		current_wr->wr.rdma.remote_addr = desc->address;
1679 		current_wr = current_wr->next;
1680 		desc++;
1681 	}
1682 
1683 #ifdef SPDK_CONFIG_RDMA_SEND_WITH_INVAL
1684 	/* Go back to the last descriptor in the list. */
1685 	desc--;
1686 	if ((device->attr.device_cap_flags & IBV_DEVICE_MEM_MGT_EXTENSIONS) != 0) {
1687 		if (desc->keyed.subtype == SPDK_NVME_SGL_SUBTYPE_INVALIDATE_KEY) {
1688 			rdma_req->rsp.wr.opcode = IBV_WR_SEND_WITH_INV;
1689 			rdma_req->rsp.wr.imm_data = desc->keyed.key;
1690 		}
1691 	}
1692 #endif
1693 
1694 	rdma_req->num_outstanding_data_wr = num_sgl_descriptors;
1695 	rdma_req->data_from_pool = true;
1696 
1697 	return 0;
1698 
1699 err_exit:
1700 	spdk_nvmf_rdma_request_free_buffers(rdma_req, &rgroup->group, &rtransport->transport, num_buffers);
1701 	nvmf_rdma_request_free_data(rdma_req, rtransport);
1702 	return rc;
1703 }
1704 
1705 static int
1706 spdk_nvmf_rdma_request_parse_sgl(struct spdk_nvmf_rdma_transport *rtransport,
1707 				 struct spdk_nvmf_rdma_device *device,
1708 				 struct spdk_nvmf_rdma_request *rdma_req)
1709 {
1710 	struct spdk_nvme_cmd			*cmd;
1711 	struct spdk_nvme_cpl			*rsp;
1712 	struct spdk_nvme_sgl_descriptor		*sgl;
1713 	int					rc;
1714 
1715 	cmd = &rdma_req->req.cmd->nvme_cmd;
1716 	rsp = &rdma_req->req.rsp->nvme_cpl;
1717 	sgl = &cmd->dptr.sgl1;
1718 
1719 	if (sgl->generic.type == SPDK_NVME_SGL_TYPE_KEYED_DATA_BLOCK &&
1720 	    (sgl->keyed.subtype == SPDK_NVME_SGL_SUBTYPE_ADDRESS ||
1721 	     sgl->keyed.subtype == SPDK_NVME_SGL_SUBTYPE_INVALIDATE_KEY)) {
1722 		if (sgl->keyed.length > rtransport->transport.opts.max_io_size) {
1723 			SPDK_ERRLOG("SGL length 0x%x exceeds max io size 0x%x\n",
1724 				    sgl->keyed.length, rtransport->transport.opts.max_io_size);
1725 			rsp->status.sc = SPDK_NVME_SC_DATA_SGL_LENGTH_INVALID;
1726 			return -1;
1727 		}
1728 #ifdef SPDK_CONFIG_RDMA_SEND_WITH_INVAL
1729 		if ((device->attr.device_cap_flags & IBV_DEVICE_MEM_MGT_EXTENSIONS) != 0) {
1730 			if (sgl->keyed.subtype == SPDK_NVME_SGL_SUBTYPE_INVALIDATE_KEY) {
1731 				rdma_req->rsp.wr.opcode = IBV_WR_SEND_WITH_INV;
1732 				rdma_req->rsp.wr.imm_data = sgl->keyed.key;
1733 			}
1734 		}
1735 #endif
1736 
1737 		/* fill request length and populate iovs */
1738 		rdma_req->req.length = sgl->keyed.length;
1739 
1740 		if (spdk_nvmf_rdma_request_fill_iovs(rtransport, device, rdma_req) < 0) {
1741 			/* No available buffers. Queue this request up. */
1742 			SPDK_DEBUGLOG(SPDK_LOG_RDMA, "No available large data buffers. Queueing request %p\n", rdma_req);
1743 			return 0;
1744 		}
1745 
1746 		/* backward compatible */
1747 		rdma_req->req.data = rdma_req->req.iov[0].iov_base;
1748 
1749 		/* rdma wr specifics */
1750 		rdma_req->data.wr.num_sge = rdma_req->req.iovcnt;
1751 		rdma_req->data.wr.wr.rdma.rkey = sgl->keyed.key;
1752 		rdma_req->data.wr.wr.rdma.remote_addr = sgl->address;
1753 		if (rdma_req->req.xfer == SPDK_NVME_DATA_CONTROLLER_TO_HOST) {
1754 			rdma_req->data.wr.opcode = IBV_WR_RDMA_WRITE;
1755 			rdma_req->data.wr.next = &rdma_req->rsp.wr;
1756 		} else if (rdma_req->req.xfer == SPDK_NVME_DATA_HOST_TO_CONTROLLER) {
1757 			rdma_req->data.wr.opcode = IBV_WR_RDMA_READ;
1758 			rdma_req->data.wr.next = NULL;
1759 		}
1760 
1761 		/* set the number of outstanding data WRs for this request. */
1762 		rdma_req->num_outstanding_data_wr = 1;
1763 
1764 		SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Request %p took %d buffer/s from central pool\n", rdma_req,
1765 			      rdma_req->req.iovcnt);
1766 
1767 		return 0;
1768 	} else if (sgl->generic.type == SPDK_NVME_SGL_TYPE_DATA_BLOCK &&
1769 		   sgl->unkeyed.subtype == SPDK_NVME_SGL_SUBTYPE_OFFSET) {
1770 		uint64_t offset = sgl->address;
1771 		uint32_t max_len = rtransport->transport.opts.in_capsule_data_size;
1772 
1773 		SPDK_DEBUGLOG(SPDK_LOG_NVMF, "In-capsule data: offset 0x%" PRIx64 ", length 0x%x\n",
1774 			      offset, sgl->unkeyed.length);
1775 
1776 		if (offset > max_len) {
1777 			SPDK_ERRLOG("In-capsule offset 0x%" PRIx64 " exceeds capsule length 0x%x\n",
1778 				    offset, max_len);
1779 			rsp->status.sc = SPDK_NVME_SC_INVALID_SGL_OFFSET;
1780 			return -1;
1781 		}
1782 		max_len -= (uint32_t)offset;
1783 
1784 		if (sgl->unkeyed.length > max_len) {
1785 			SPDK_ERRLOG("In-capsule data length 0x%x exceeds capsule length 0x%x\n",
1786 				    sgl->unkeyed.length, max_len);
1787 			rsp->status.sc = SPDK_NVME_SC_DATA_SGL_LENGTH_INVALID;
1788 			return -1;
1789 		}
1790 
1791 		rdma_req->num_outstanding_data_wr = 0;
1792 		rdma_req->req.data = rdma_req->recv->buf + offset;
1793 		rdma_req->data_from_pool = false;
1794 		rdma_req->req.length = sgl->unkeyed.length;
1795 
1796 		rdma_req->req.iov[0].iov_base = rdma_req->req.data;
1797 		rdma_req->req.iov[0].iov_len = rdma_req->req.length;
1798 		rdma_req->req.iovcnt = 1;
1799 
1800 		return 0;
1801 	} else if (sgl->generic.type == SPDK_NVME_SGL_TYPE_LAST_SEGMENT &&
1802 		   sgl->unkeyed.subtype == SPDK_NVME_SGL_SUBTYPE_OFFSET) {
1803 
1804 		rc = nvmf_rdma_request_fill_iovs_multi_sgl(rtransport, device, rdma_req);
1805 		if (rc == -ENOMEM) {
1806 			SPDK_DEBUGLOG(SPDK_LOG_RDMA, "No available large data buffers. Queueing request %p\n", rdma_req);
1807 			return 0;
1808 		} else if (rc == -EINVAL) {
1809 			SPDK_ERRLOG("Multi SGL element request length exceeds the max I/O size\n");
1810 			return -1;
1811 		}
1812 
1813 		/* backward compatible */
1814 		rdma_req->req.data = rdma_req->req.iov[0].iov_base;
1815 
1816 		SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Request %p took %d buffer/s from central pool\n", rdma_req,
1817 			      rdma_req->req.iovcnt);
1818 
1819 		return 0;
1820 	}
1821 
1822 	SPDK_ERRLOG("Invalid NVMf I/O Command SGL:  Type 0x%x, Subtype 0x%x\n",
1823 		    sgl->generic.type, sgl->generic.subtype);
1824 	rsp->status.sc = SPDK_NVME_SC_SGL_DESCRIPTOR_TYPE_INVALID;
1825 	return -1;
1826 }
1827 
1828 static void
1829 nvmf_rdma_request_free(struct spdk_nvmf_rdma_request *rdma_req,
1830 		       struct spdk_nvmf_rdma_transport	*rtransport)
1831 {
1832 	struct spdk_nvmf_rdma_qpair		*rqpair;
1833 	struct spdk_nvmf_rdma_poll_group	*rgroup;
1834 
1835 	rqpair = SPDK_CONTAINEROF(rdma_req->req.qpair, struct spdk_nvmf_rdma_qpair, qpair);
1836 	if (rdma_req->data_from_pool) {
1837 		rgroup = rqpair->poller->group;
1838 
1839 		spdk_nvmf_rdma_request_free_buffers(rdma_req, &rgroup->group, &rtransport->transport,
1840 						    rdma_req->req.iovcnt);
1841 	}
1842 	nvmf_rdma_request_free_data(rdma_req, rtransport);
1843 	rdma_req->req.length = 0;
1844 	rdma_req->req.iovcnt = 0;
1845 	rdma_req->req.data = NULL;
1846 	rdma_req->rsp.wr.next = NULL;
1847 	rdma_req->data.wr.next = NULL;
1848 	rqpair->qd--;
1849 
1850 	STAILQ_INSERT_HEAD(&rqpair->resources->free_queue, rdma_req, state_link);
1851 	rdma_req->state = RDMA_REQUEST_STATE_FREE;
1852 }
1853 
1854 static bool
1855 spdk_nvmf_rdma_request_process(struct spdk_nvmf_rdma_transport *rtransport,
1856 			       struct spdk_nvmf_rdma_request *rdma_req)
1857 {
1858 	struct spdk_nvmf_rdma_qpair	*rqpair;
1859 	struct spdk_nvmf_rdma_device	*device;
1860 	struct spdk_nvmf_rdma_poll_group *rgroup;
1861 	struct spdk_nvme_cpl		*rsp = &rdma_req->req.rsp->nvme_cpl;
1862 	int				rc;
1863 	struct spdk_nvmf_rdma_recv	*rdma_recv;
1864 	enum spdk_nvmf_rdma_request_state prev_state;
1865 	bool				progress = false;
1866 	int				data_posted;
1867 
1868 	rqpair = SPDK_CONTAINEROF(rdma_req->req.qpair, struct spdk_nvmf_rdma_qpair, qpair);
1869 	device = rqpair->port->device;
1870 	rgroup = rqpair->poller->group;
1871 
1872 	assert(rdma_req->state != RDMA_REQUEST_STATE_FREE);
1873 
1874 	/* If the queue pair is in an error state, force the request to the completed state
1875 	 * to release resources. */
1876 	if (rqpair->ibv_state == IBV_QPS_ERR || rqpair->qpair.state != SPDK_NVMF_QPAIR_ACTIVE) {
1877 		if (rdma_req->state == RDMA_REQUEST_STATE_NEED_BUFFER) {
1878 			STAILQ_REMOVE(&rgroup->pending_data_buf_queue, rdma_req, spdk_nvmf_rdma_request, state_link);
1879 		} else if (rdma_req->state == RDMA_REQUEST_STATE_DATA_TRANSFER_TO_CONTROLLER_PENDING) {
1880 			STAILQ_REMOVE(&rqpair->pending_rdma_read_queue, rdma_req, spdk_nvmf_rdma_request, state_link);
1881 		} else if (rdma_req->state == RDMA_REQUEST_STATE_DATA_TRANSFER_TO_HOST_PENDING) {
1882 			STAILQ_REMOVE(&rqpair->pending_rdma_write_queue, rdma_req, spdk_nvmf_rdma_request, state_link);
1883 		}
1884 		rdma_req->state = RDMA_REQUEST_STATE_COMPLETED;
1885 	}
1886 
1887 	/* The loop here is to allow for several back-to-back state changes. */
1888 	do {
1889 		prev_state = rdma_req->state;
1890 
1891 		SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Request %p entering state %d\n", rdma_req, prev_state);
1892 
1893 		switch (rdma_req->state) {
1894 		case RDMA_REQUEST_STATE_FREE:
1895 			/* Some external code must kick a request into RDMA_REQUEST_STATE_NEW
1896 			 * to escape this state. */
1897 			break;
1898 		case RDMA_REQUEST_STATE_NEW:
1899 			spdk_trace_record(TRACE_RDMA_REQUEST_STATE_NEW, 0, 0,
1900 					  (uintptr_t)rdma_req, (uintptr_t)rqpair->cm_id);
1901 			rdma_recv = rdma_req->recv;
1902 
1903 			/* The first element of the SGL is the NVMe command */
1904 			rdma_req->req.cmd = (union nvmf_h2c_msg *)rdma_recv->sgl[0].addr;
1905 			memset(rdma_req->req.rsp, 0, sizeof(*rdma_req->req.rsp));
1906 
1907 			if (rqpair->ibv_state == IBV_QPS_ERR  || rqpair->qpair.state != SPDK_NVMF_QPAIR_ACTIVE) {
1908 				rdma_req->state = RDMA_REQUEST_STATE_COMPLETED;
1909 				break;
1910 			}
1911 
1912 			/* The next state transition depends on the data transfer needs of this request. */
1913 			rdma_req->req.xfer = spdk_nvmf_rdma_request_get_xfer(rdma_req);
1914 
1915 			/* If no data to transfer, ready to execute. */
1916 			if (rdma_req->req.xfer == SPDK_NVME_DATA_NONE) {
1917 				rdma_req->state = RDMA_REQUEST_STATE_READY_TO_EXECUTE;
1918 				break;
1919 			}
1920 
1921 			rdma_req->state = RDMA_REQUEST_STATE_NEED_BUFFER;
1922 			STAILQ_INSERT_TAIL(&rgroup->pending_data_buf_queue, rdma_req, state_link);
1923 			break;
1924 		case RDMA_REQUEST_STATE_NEED_BUFFER:
1925 			spdk_trace_record(TRACE_RDMA_REQUEST_STATE_NEED_BUFFER, 0, 0,
1926 					  (uintptr_t)rdma_req, (uintptr_t)rqpair->cm_id);
1927 
1928 			assert(rdma_req->req.xfer != SPDK_NVME_DATA_NONE);
1929 
1930 			if (rdma_req != STAILQ_FIRST(&rgroup->pending_data_buf_queue)) {
1931 				/* This request needs to wait in line to obtain a buffer */
1932 				break;
1933 			}
1934 
1935 			/* Try to get a data buffer */
1936 			rc = spdk_nvmf_rdma_request_parse_sgl(rtransport, device, rdma_req);
1937 			if (rc < 0) {
1938 				STAILQ_REMOVE_HEAD(&rgroup->pending_data_buf_queue, state_link);
1939 				rsp->status.sc = SPDK_NVME_SC_INTERNAL_DEVICE_ERROR;
1940 				rdma_req->state = RDMA_REQUEST_STATE_READY_TO_COMPLETE;
1941 				break;
1942 			}
1943 
1944 			if (!rdma_req->req.data) {
1945 				/* No buffers available. */
1946 				break;
1947 			}
1948 
1949 			STAILQ_REMOVE_HEAD(&rgroup->pending_data_buf_queue, state_link);
1950 
1951 			/* If data is transferring from host to controller and the data didn't
1952 			 * arrive using in capsule data, we need to do a transfer from the host.
1953 			 */
1954 			if (rdma_req->req.xfer == SPDK_NVME_DATA_HOST_TO_CONTROLLER && rdma_req->data_from_pool) {
1955 				STAILQ_INSERT_TAIL(&rqpair->pending_rdma_read_queue, rdma_req, state_link);
1956 				rdma_req->state = RDMA_REQUEST_STATE_DATA_TRANSFER_TO_CONTROLLER_PENDING;
1957 				break;
1958 			}
1959 
1960 			rdma_req->state = RDMA_REQUEST_STATE_READY_TO_EXECUTE;
1961 			break;
1962 		case RDMA_REQUEST_STATE_DATA_TRANSFER_TO_CONTROLLER_PENDING:
1963 			spdk_trace_record(TRACE_RDMA_REQUEST_STATE_DATA_TRANSFER_TO_CONTROLLER_PENDING, 0, 0,
1964 					  (uintptr_t)rdma_req, (uintptr_t)rqpair->cm_id);
1965 
1966 			if (rdma_req != STAILQ_FIRST(&rqpair->pending_rdma_read_queue)) {
1967 				/* This request needs to wait in line to perform RDMA */
1968 				break;
1969 			}
1970 			if (rqpair->current_send_depth + rdma_req->num_outstanding_data_wr > rqpair->max_send_depth
1971 			    || rqpair->current_read_depth + rdma_req->num_outstanding_data_wr > rqpair->max_read_depth) {
1972 				/* We can only have so many WRs outstanding. we have to wait until some finish. */
1973 				break;
1974 			}
1975 
1976 			/* We have already verified that this request is the head of the queue. */
1977 			STAILQ_REMOVE_HEAD(&rqpair->pending_rdma_read_queue, state_link);
1978 
1979 			rc = request_transfer_in(&rdma_req->req);
1980 			if (!rc) {
1981 				rdma_req->state = RDMA_REQUEST_STATE_TRANSFERRING_HOST_TO_CONTROLLER;
1982 			} else {
1983 				rsp->status.sc = SPDK_NVME_SC_INTERNAL_DEVICE_ERROR;
1984 				rdma_req->state = RDMA_REQUEST_STATE_READY_TO_COMPLETE;
1985 			}
1986 			break;
1987 		case RDMA_REQUEST_STATE_TRANSFERRING_HOST_TO_CONTROLLER:
1988 			spdk_trace_record(TRACE_RDMA_REQUEST_STATE_TRANSFERRING_HOST_TO_CONTROLLER, 0, 0,
1989 					  (uintptr_t)rdma_req, (uintptr_t)rqpair->cm_id);
1990 			/* Some external code must kick a request into RDMA_REQUEST_STATE_READY_TO_EXECUTE
1991 			 * to escape this state. */
1992 			break;
1993 		case RDMA_REQUEST_STATE_READY_TO_EXECUTE:
1994 			spdk_trace_record(TRACE_RDMA_REQUEST_STATE_READY_TO_EXECUTE, 0, 0,
1995 					  (uintptr_t)rdma_req, (uintptr_t)rqpair->cm_id);
1996 			rdma_req->state = RDMA_REQUEST_STATE_EXECUTING;
1997 			spdk_nvmf_request_exec(&rdma_req->req);
1998 			break;
1999 		case RDMA_REQUEST_STATE_EXECUTING:
2000 			spdk_trace_record(TRACE_RDMA_REQUEST_STATE_EXECUTING, 0, 0,
2001 					  (uintptr_t)rdma_req, (uintptr_t)rqpair->cm_id);
2002 			/* Some external code must kick a request into RDMA_REQUEST_STATE_EXECUTED
2003 			 * to escape this state. */
2004 			break;
2005 		case RDMA_REQUEST_STATE_EXECUTED:
2006 			spdk_trace_record(TRACE_RDMA_REQUEST_STATE_EXECUTED, 0, 0,
2007 					  (uintptr_t)rdma_req, (uintptr_t)rqpair->cm_id);
2008 			if (rdma_req->req.xfer == SPDK_NVME_DATA_CONTROLLER_TO_HOST) {
2009 				STAILQ_INSERT_TAIL(&rqpair->pending_rdma_write_queue, rdma_req, state_link);
2010 				rdma_req->state = RDMA_REQUEST_STATE_DATA_TRANSFER_TO_HOST_PENDING;
2011 			} else {
2012 				rdma_req->state = RDMA_REQUEST_STATE_READY_TO_COMPLETE;
2013 			}
2014 			break;
2015 		case RDMA_REQUEST_STATE_DATA_TRANSFER_TO_HOST_PENDING:
2016 			spdk_trace_record(TRACE_RDMA_REQUEST_STATE_DATA_TRANSFER_TO_HOST_PENDING, 0, 0,
2017 					  (uintptr_t)rdma_req, (uintptr_t)rqpair->cm_id);
2018 
2019 			if (rdma_req != STAILQ_FIRST(&rqpair->pending_rdma_write_queue)) {
2020 				/* This request needs to wait in line to perform RDMA */
2021 				break;
2022 			}
2023 			if ((rqpair->current_send_depth + rdma_req->num_outstanding_data_wr + 1) >
2024 			    rqpair->max_send_depth) {
2025 				/* We can only have so many WRs outstanding. we have to wait until some finish.
2026 				 * +1 since each request has an additional wr in the resp. */
2027 				break;
2028 			}
2029 
2030 			/* We have already verified that this request is the head of the queue. */
2031 			STAILQ_REMOVE_HEAD(&rqpair->pending_rdma_write_queue, state_link);
2032 
2033 			/* The data transfer will be kicked off from
2034 			 * RDMA_REQUEST_STATE_READY_TO_COMPLETE state.
2035 			 */
2036 			rdma_req->state = RDMA_REQUEST_STATE_READY_TO_COMPLETE;
2037 			break;
2038 		case RDMA_REQUEST_STATE_READY_TO_COMPLETE:
2039 			spdk_trace_record(TRACE_RDMA_REQUEST_STATE_READY_TO_COMPLETE, 0, 0,
2040 					  (uintptr_t)rdma_req, (uintptr_t)rqpair->cm_id);
2041 			rc = request_transfer_out(&rdma_req->req, &data_posted);
2042 			assert(rc == 0); /* No good way to handle this currently */
2043 			if (rc) {
2044 				rdma_req->state = RDMA_REQUEST_STATE_COMPLETED;
2045 			} else {
2046 				rdma_req->state = data_posted ? RDMA_REQUEST_STATE_TRANSFERRING_CONTROLLER_TO_HOST :
2047 						  RDMA_REQUEST_STATE_COMPLETING;
2048 			}
2049 			break;
2050 		case RDMA_REQUEST_STATE_TRANSFERRING_CONTROLLER_TO_HOST:
2051 			spdk_trace_record(TRACE_RDMA_REQUEST_STATE_TRANSFERRING_CONTROLLER_TO_HOST, 0, 0,
2052 					  (uintptr_t)rdma_req, (uintptr_t)rqpair->cm_id);
2053 			/* Some external code must kick a request into RDMA_REQUEST_STATE_COMPLETED
2054 			 * to escape this state. */
2055 			break;
2056 		case RDMA_REQUEST_STATE_COMPLETING:
2057 			spdk_trace_record(TRACE_RDMA_REQUEST_STATE_COMPLETING, 0, 0,
2058 					  (uintptr_t)rdma_req, (uintptr_t)rqpair->cm_id);
2059 			/* Some external code must kick a request into RDMA_REQUEST_STATE_COMPLETED
2060 			 * to escape this state. */
2061 			break;
2062 		case RDMA_REQUEST_STATE_COMPLETED:
2063 			spdk_trace_record(TRACE_RDMA_REQUEST_STATE_COMPLETED, 0, 0,
2064 					  (uintptr_t)rdma_req, (uintptr_t)rqpair->cm_id);
2065 
2066 			nvmf_rdma_request_free(rdma_req, rtransport);
2067 			break;
2068 		case RDMA_REQUEST_NUM_STATES:
2069 		default:
2070 			assert(0);
2071 			break;
2072 		}
2073 
2074 		if (rdma_req->state != prev_state) {
2075 			progress = true;
2076 		}
2077 	} while (rdma_req->state != prev_state);
2078 
2079 	return progress;
2080 }
2081 
2082 /* Public API callbacks begin here */
2083 
2084 #define SPDK_NVMF_RDMA_DEFAULT_MAX_QUEUE_DEPTH 128
2085 #define SPDK_NVMF_RDMA_DEFAULT_AQ_DEPTH 128
2086 #define SPDK_NVMF_RDMA_DEFAULT_SRQ_DEPTH 4096
2087 #define SPDK_NVMF_RDMA_DEFAULT_MAX_QPAIRS_PER_CTRLR 64
2088 #define SPDK_NVMF_RDMA_DEFAULT_IN_CAPSULE_DATA_SIZE 4096
2089 #define SPDK_NVMF_RDMA_DEFAULT_MAX_IO_SIZE 131072
2090 #define SPDK_NVMF_RDMA_MIN_IO_BUFFER_SIZE (SPDK_NVMF_RDMA_DEFAULT_MAX_IO_SIZE / SPDK_NVMF_MAX_SGL_ENTRIES)
2091 #define SPDK_NVMF_RDMA_DEFAULT_NUM_SHARED_BUFFERS 4095
2092 #define SPDK_NVMF_RDMA_DEFAULT_BUFFER_CACHE_SIZE 32
2093 #define SPDK_NVMF_RDMA_DEFAULT_NO_SRQ false;
2094 
2095 static void
2096 spdk_nvmf_rdma_opts_init(struct spdk_nvmf_transport_opts *opts)
2097 {
2098 	opts->max_queue_depth =		SPDK_NVMF_RDMA_DEFAULT_MAX_QUEUE_DEPTH;
2099 	opts->max_qpairs_per_ctrlr =	SPDK_NVMF_RDMA_DEFAULT_MAX_QPAIRS_PER_CTRLR;
2100 	opts->in_capsule_data_size =	SPDK_NVMF_RDMA_DEFAULT_IN_CAPSULE_DATA_SIZE;
2101 	opts->max_io_size =		SPDK_NVMF_RDMA_DEFAULT_MAX_IO_SIZE;
2102 	opts->io_unit_size =		SPDK_NVMF_RDMA_MIN_IO_BUFFER_SIZE;
2103 	opts->max_aq_depth =		SPDK_NVMF_RDMA_DEFAULT_AQ_DEPTH;
2104 	opts->num_shared_buffers =	SPDK_NVMF_RDMA_DEFAULT_NUM_SHARED_BUFFERS;
2105 	opts->buf_cache_size =		SPDK_NVMF_RDMA_DEFAULT_BUFFER_CACHE_SIZE;
2106 	opts->max_srq_depth =		SPDK_NVMF_RDMA_DEFAULT_SRQ_DEPTH;
2107 	opts->no_srq =			SPDK_NVMF_RDMA_DEFAULT_NO_SRQ
2108 }
2109 
2110 const struct spdk_mem_map_ops g_nvmf_rdma_map_ops = {
2111 	.notify_cb = spdk_nvmf_rdma_mem_notify,
2112 	.are_contiguous = spdk_nvmf_rdma_check_contiguous_entries
2113 };
2114 
2115 static int spdk_nvmf_rdma_destroy(struct spdk_nvmf_transport *transport);
2116 
2117 static struct spdk_nvmf_transport *
2118 spdk_nvmf_rdma_create(struct spdk_nvmf_transport_opts *opts)
2119 {
2120 	int rc;
2121 	struct spdk_nvmf_rdma_transport *rtransport;
2122 	struct spdk_nvmf_rdma_device	*device, *tmp;
2123 	struct ibv_pd			*pd;
2124 	struct ibv_context		**contexts;
2125 	uint32_t			i;
2126 	int				flag;
2127 	uint32_t			sge_count;
2128 	uint32_t			min_shared_buffers;
2129 	int				max_device_sge = SPDK_NVMF_MAX_SGL_ENTRIES;
2130 
2131 	rtransport = calloc(1, sizeof(*rtransport));
2132 	if (!rtransport) {
2133 		return NULL;
2134 	}
2135 
2136 	if (pthread_mutex_init(&rtransport->lock, NULL)) {
2137 		SPDK_ERRLOG("pthread_mutex_init() failed\n");
2138 		free(rtransport);
2139 		return NULL;
2140 	}
2141 
2142 	TAILQ_INIT(&rtransport->devices);
2143 	TAILQ_INIT(&rtransport->ports);
2144 
2145 	rtransport->transport.ops = &spdk_nvmf_transport_rdma;
2146 
2147 	SPDK_INFOLOG(SPDK_LOG_RDMA, "*** RDMA Transport Init ***\n"
2148 		     "  Transport opts:  max_ioq_depth=%d, max_io_size=%d,\n"
2149 		     "  max_qpairs_per_ctrlr=%d, io_unit_size=%d,\n"
2150 		     "  in_capsule_data_size=%d, max_aq_depth=%d,\n"
2151 		     "  num_shared_buffers=%d, max_srq_depth=%d, no_srq=%d\n",
2152 		     opts->max_queue_depth,
2153 		     opts->max_io_size,
2154 		     opts->max_qpairs_per_ctrlr,
2155 		     opts->io_unit_size,
2156 		     opts->in_capsule_data_size,
2157 		     opts->max_aq_depth,
2158 		     opts->num_shared_buffers,
2159 		     opts->max_srq_depth,
2160 		     opts->no_srq);
2161 
2162 	/* I/O unit size cannot be larger than max I/O size */
2163 	if (opts->io_unit_size > opts->max_io_size) {
2164 		opts->io_unit_size = opts->max_io_size;
2165 	}
2166 
2167 	if (opts->num_shared_buffers < (SPDK_NVMF_MAX_SGL_ENTRIES * 2)) {
2168 		SPDK_ERRLOG("The number of shared data buffers (%d) is less than"
2169 			    "the minimum number required to guarantee that forward progress can be made (%d)\n",
2170 			    opts->num_shared_buffers, (SPDK_NVMF_MAX_SGL_ENTRIES * 2));
2171 		spdk_nvmf_rdma_destroy(&rtransport->transport);
2172 		return NULL;
2173 	}
2174 
2175 	min_shared_buffers = spdk_thread_get_count() * opts->buf_cache_size;
2176 	if (min_shared_buffers > opts->num_shared_buffers) {
2177 		SPDK_ERRLOG("There are not enough buffers to satisfy"
2178 			    "per-poll group caches for each thread. (%" PRIu32 ")"
2179 			    "supplied. (%" PRIu32 ") required\n", opts->num_shared_buffers, min_shared_buffers);
2180 		SPDK_ERRLOG("Please specify a larger number of shared buffers\n");
2181 		spdk_nvmf_rdma_destroy(&rtransport->transport);
2182 		return NULL;
2183 	}
2184 
2185 	sge_count = opts->max_io_size / opts->io_unit_size;
2186 	if (sge_count > NVMF_DEFAULT_TX_SGE) {
2187 		SPDK_ERRLOG("Unsupported IO Unit size specified, %d bytes\n", opts->io_unit_size);
2188 		spdk_nvmf_rdma_destroy(&rtransport->transport);
2189 		return NULL;
2190 	}
2191 
2192 	rtransport->event_channel = rdma_create_event_channel();
2193 	if (rtransport->event_channel == NULL) {
2194 		SPDK_ERRLOG("rdma_create_event_channel() failed, %s\n", spdk_strerror(errno));
2195 		spdk_nvmf_rdma_destroy(&rtransport->transport);
2196 		return NULL;
2197 	}
2198 
2199 	flag = fcntl(rtransport->event_channel->fd, F_GETFL);
2200 	if (fcntl(rtransport->event_channel->fd, F_SETFL, flag | O_NONBLOCK) < 0) {
2201 		SPDK_ERRLOG("fcntl can't set nonblocking mode for socket, fd: %d (%s)\n",
2202 			    rtransport->event_channel->fd, spdk_strerror(errno));
2203 		spdk_nvmf_rdma_destroy(&rtransport->transport);
2204 		return NULL;
2205 	}
2206 
2207 	rtransport->data_wr_pool = spdk_mempool_create("spdk_nvmf_rdma_wr_data",
2208 				   opts->max_queue_depth * SPDK_NVMF_MAX_SGL_ENTRIES,
2209 				   sizeof(struct spdk_nvmf_rdma_request_data),
2210 				   SPDK_MEMPOOL_DEFAULT_CACHE_SIZE,
2211 				   SPDK_ENV_SOCKET_ID_ANY);
2212 	if (!rtransport->data_wr_pool) {
2213 		SPDK_ERRLOG("Unable to allocate work request pool for poll group\n");
2214 		spdk_nvmf_rdma_destroy(&rtransport->transport);
2215 		return NULL;
2216 	}
2217 
2218 	contexts = rdma_get_devices(NULL);
2219 	if (contexts == NULL) {
2220 		SPDK_ERRLOG("rdma_get_devices() failed: %s (%d)\n", spdk_strerror(errno), errno);
2221 		spdk_nvmf_rdma_destroy(&rtransport->transport);
2222 		return NULL;
2223 	}
2224 
2225 	i = 0;
2226 	rc = 0;
2227 	while (contexts[i] != NULL) {
2228 		device = calloc(1, sizeof(*device));
2229 		if (!device) {
2230 			SPDK_ERRLOG("Unable to allocate memory for RDMA devices.\n");
2231 			rc = -ENOMEM;
2232 			break;
2233 		}
2234 		device->context = contexts[i];
2235 		rc = ibv_query_device(device->context, &device->attr);
2236 		if (rc < 0) {
2237 			SPDK_ERRLOG("Failed to query RDMA device attributes.\n");
2238 			free(device);
2239 			break;
2240 
2241 		}
2242 
2243 		max_device_sge = spdk_min(max_device_sge, device->attr.max_sge);
2244 
2245 #ifdef SPDK_CONFIG_RDMA_SEND_WITH_INVAL
2246 		if ((device->attr.device_cap_flags & IBV_DEVICE_MEM_MGT_EXTENSIONS) == 0) {
2247 			SPDK_WARNLOG("The libibverbs on this system supports SEND_WITH_INVALIDATE,");
2248 			SPDK_WARNLOG("but the device with vendor ID %u does not.\n", device->attr.vendor_id);
2249 		}
2250 
2251 		/**
2252 		 * The vendor ID is assigned by the IEEE and an ID of 0 implies Soft-RoCE.
2253 		 * The Soft-RoCE RXE driver does not currently support send with invalidate,
2254 		 * but incorrectly reports that it does. There are changes making their way
2255 		 * through the kernel now that will enable this feature. When they are merged,
2256 		 * we can conditionally enable this feature.
2257 		 *
2258 		 * TODO: enable this for versions of the kernel rxe driver that support it.
2259 		 */
2260 		if (device->attr.vendor_id == 0) {
2261 			device->attr.device_cap_flags &= ~(IBV_DEVICE_MEM_MGT_EXTENSIONS);
2262 		}
2263 #endif
2264 
2265 		/* set up device context async ev fd as NON_BLOCKING */
2266 		flag = fcntl(device->context->async_fd, F_GETFL);
2267 		rc = fcntl(device->context->async_fd, F_SETFL, flag | O_NONBLOCK);
2268 		if (rc < 0) {
2269 			SPDK_ERRLOG("Failed to set context async fd to NONBLOCK.\n");
2270 			free(device);
2271 			break;
2272 		}
2273 
2274 		TAILQ_INSERT_TAIL(&rtransport->devices, device, link);
2275 		i++;
2276 
2277 		pd = NULL;
2278 		if (g_nvmf_hooks.get_ibv_pd) {
2279 			pd = g_nvmf_hooks.get_ibv_pd(NULL, device->context);
2280 		}
2281 
2282 		if (!g_nvmf_hooks.get_ibv_pd) {
2283 			device->pd = ibv_alloc_pd(device->context);
2284 			if (!device->pd) {
2285 				SPDK_ERRLOG("Unable to allocate protection domain.\n");
2286 				spdk_nvmf_rdma_destroy(&rtransport->transport);
2287 				return NULL;
2288 			}
2289 		} else {
2290 			device->pd = pd;
2291 		}
2292 
2293 		assert(device->map == NULL);
2294 
2295 		device->map = spdk_mem_map_alloc(0, &g_nvmf_rdma_map_ops, device->pd);
2296 		if (!device->map) {
2297 			SPDK_ERRLOG("Unable to allocate memory map for listen address\n");
2298 			spdk_nvmf_rdma_destroy(&rtransport->transport);
2299 			return NULL;
2300 		}
2301 
2302 		assert(device->map != NULL);
2303 		assert(device->pd != NULL);
2304 	}
2305 	rdma_free_devices(contexts);
2306 
2307 	if (opts->io_unit_size * max_device_sge < opts->max_io_size) {
2308 		/* divide and round up. */
2309 		opts->io_unit_size = (opts->max_io_size + max_device_sge - 1) / max_device_sge;
2310 
2311 		/* round up to the nearest 4k. */
2312 		opts->io_unit_size = (opts->io_unit_size + NVMF_DATA_BUFFER_ALIGNMENT - 1) & ~NVMF_DATA_BUFFER_MASK;
2313 
2314 		opts->io_unit_size = spdk_max(opts->io_unit_size, SPDK_NVMF_RDMA_MIN_IO_BUFFER_SIZE);
2315 		SPDK_NOTICELOG("Adjusting the io unit size to fit the device's maximum I/O size. New I/O unit size %u\n",
2316 			       opts->io_unit_size);
2317 	}
2318 
2319 	if (rc < 0) {
2320 		spdk_nvmf_rdma_destroy(&rtransport->transport);
2321 		return NULL;
2322 	}
2323 
2324 	/* Set up poll descriptor array to monitor events from RDMA and IB
2325 	 * in a single poll syscall
2326 	 */
2327 	rtransport->npoll_fds = i + 1;
2328 	i = 0;
2329 	rtransport->poll_fds = calloc(rtransport->npoll_fds, sizeof(struct pollfd));
2330 	if (rtransport->poll_fds == NULL) {
2331 		SPDK_ERRLOG("poll_fds allocation failed\n");
2332 		spdk_nvmf_rdma_destroy(&rtransport->transport);
2333 		return NULL;
2334 	}
2335 
2336 	rtransport->poll_fds[i].fd = rtransport->event_channel->fd;
2337 	rtransport->poll_fds[i++].events = POLLIN;
2338 
2339 	TAILQ_FOREACH_SAFE(device, &rtransport->devices, link, tmp) {
2340 		rtransport->poll_fds[i].fd = device->context->async_fd;
2341 		rtransport->poll_fds[i++].events = POLLIN;
2342 	}
2343 
2344 	return &rtransport->transport;
2345 }
2346 
2347 static int
2348 spdk_nvmf_rdma_destroy(struct spdk_nvmf_transport *transport)
2349 {
2350 	struct spdk_nvmf_rdma_transport	*rtransport;
2351 	struct spdk_nvmf_rdma_port	*port, *port_tmp;
2352 	struct spdk_nvmf_rdma_device	*device, *device_tmp;
2353 
2354 	rtransport = SPDK_CONTAINEROF(transport, struct spdk_nvmf_rdma_transport, transport);
2355 
2356 	TAILQ_FOREACH_SAFE(port, &rtransport->ports, link, port_tmp) {
2357 		TAILQ_REMOVE(&rtransport->ports, port, link);
2358 		rdma_destroy_id(port->id);
2359 		free(port);
2360 	}
2361 
2362 	if (rtransport->poll_fds != NULL) {
2363 		free(rtransport->poll_fds);
2364 	}
2365 
2366 	if (rtransport->event_channel != NULL) {
2367 		rdma_destroy_event_channel(rtransport->event_channel);
2368 	}
2369 
2370 	TAILQ_FOREACH_SAFE(device, &rtransport->devices, link, device_tmp) {
2371 		TAILQ_REMOVE(&rtransport->devices, device, link);
2372 		if (device->map) {
2373 			spdk_mem_map_free(&device->map);
2374 		}
2375 		if (device->pd) {
2376 			if (!g_nvmf_hooks.get_ibv_pd) {
2377 				ibv_dealloc_pd(device->pd);
2378 			}
2379 		}
2380 		free(device);
2381 	}
2382 
2383 	if (rtransport->data_wr_pool != NULL) {
2384 		if (spdk_mempool_count(rtransport->data_wr_pool) !=
2385 		    (transport->opts.max_queue_depth * SPDK_NVMF_MAX_SGL_ENTRIES)) {
2386 			SPDK_ERRLOG("transport wr pool count is %zu but should be %u\n",
2387 				    spdk_mempool_count(rtransport->data_wr_pool),
2388 				    transport->opts.max_queue_depth * SPDK_NVMF_MAX_SGL_ENTRIES);
2389 		}
2390 	}
2391 
2392 	spdk_mempool_free(rtransport->data_wr_pool);
2393 	pthread_mutex_destroy(&rtransport->lock);
2394 	free(rtransport);
2395 
2396 	return 0;
2397 }
2398 
2399 static int
2400 spdk_nvmf_rdma_trid_from_cm_id(struct rdma_cm_id *id,
2401 			       struct spdk_nvme_transport_id *trid,
2402 			       bool peer);
2403 
2404 static int
2405 spdk_nvmf_rdma_listen(struct spdk_nvmf_transport *transport,
2406 		      const struct spdk_nvme_transport_id *trid)
2407 {
2408 	struct spdk_nvmf_rdma_transport	*rtransport;
2409 	struct spdk_nvmf_rdma_device	*device;
2410 	struct spdk_nvmf_rdma_port	*port_tmp, *port;
2411 	struct addrinfo			*res;
2412 	struct addrinfo			hints;
2413 	int				family;
2414 	int				rc;
2415 
2416 	rtransport = SPDK_CONTAINEROF(transport, struct spdk_nvmf_rdma_transport, transport);
2417 
2418 	port = calloc(1, sizeof(*port));
2419 	if (!port) {
2420 		return -ENOMEM;
2421 	}
2422 
2423 	/* Selectively copy the trid. Things like NQN don't matter here - that
2424 	 * mapping is enforced elsewhere.
2425 	 */
2426 	port->trid.trtype = SPDK_NVME_TRANSPORT_RDMA;
2427 	port->trid.adrfam = trid->adrfam;
2428 	snprintf(port->trid.traddr, sizeof(port->trid.traddr), "%s", trid->traddr);
2429 	snprintf(port->trid.trsvcid, sizeof(port->trid.trsvcid), "%s", trid->trsvcid);
2430 
2431 	pthread_mutex_lock(&rtransport->lock);
2432 	assert(rtransport->event_channel != NULL);
2433 	TAILQ_FOREACH(port_tmp, &rtransport->ports, link) {
2434 		if (spdk_nvme_transport_id_compare(&port_tmp->trid, &port->trid) == 0) {
2435 			port_tmp->ref++;
2436 			free(port);
2437 			/* Already listening at this address */
2438 			pthread_mutex_unlock(&rtransport->lock);
2439 			return 0;
2440 		}
2441 	}
2442 
2443 	rc = rdma_create_id(rtransport->event_channel, &port->id, port, RDMA_PS_TCP);
2444 	if (rc < 0) {
2445 		SPDK_ERRLOG("rdma_create_id() failed\n");
2446 		free(port);
2447 		pthread_mutex_unlock(&rtransport->lock);
2448 		return rc;
2449 	}
2450 
2451 	switch (port->trid.adrfam) {
2452 	case SPDK_NVMF_ADRFAM_IPV4:
2453 		family = AF_INET;
2454 		break;
2455 	case SPDK_NVMF_ADRFAM_IPV6:
2456 		family = AF_INET6;
2457 		break;
2458 	default:
2459 		SPDK_ERRLOG("Unhandled ADRFAM %d\n", port->trid.adrfam);
2460 		free(port);
2461 		pthread_mutex_unlock(&rtransport->lock);
2462 		return -EINVAL;
2463 	}
2464 
2465 	memset(&hints, 0, sizeof(hints));
2466 	hints.ai_family = family;
2467 	hints.ai_flags = AI_NUMERICSERV;
2468 	hints.ai_socktype = SOCK_STREAM;
2469 	hints.ai_protocol = 0;
2470 
2471 	rc = getaddrinfo(port->trid.traddr, port->trid.trsvcid, &hints, &res);
2472 	if (rc) {
2473 		SPDK_ERRLOG("getaddrinfo failed: %s (%d)\n", gai_strerror(rc), rc);
2474 		free(port);
2475 		pthread_mutex_unlock(&rtransport->lock);
2476 		return -EINVAL;
2477 	}
2478 
2479 	rc = rdma_bind_addr(port->id, res->ai_addr);
2480 	freeaddrinfo(res);
2481 
2482 	if (rc < 0) {
2483 		SPDK_ERRLOG("rdma_bind_addr() failed\n");
2484 		rdma_destroy_id(port->id);
2485 		free(port);
2486 		pthread_mutex_unlock(&rtransport->lock);
2487 		return rc;
2488 	}
2489 
2490 	if (!port->id->verbs) {
2491 		SPDK_ERRLOG("ibv_context is null\n");
2492 		rdma_destroy_id(port->id);
2493 		free(port);
2494 		pthread_mutex_unlock(&rtransport->lock);
2495 		return -1;
2496 	}
2497 
2498 	rc = rdma_listen(port->id, 10); /* 10 = backlog */
2499 	if (rc < 0) {
2500 		SPDK_ERRLOG("rdma_listen() failed\n");
2501 		rdma_destroy_id(port->id);
2502 		free(port);
2503 		pthread_mutex_unlock(&rtransport->lock);
2504 		return rc;
2505 	}
2506 
2507 	TAILQ_FOREACH(device, &rtransport->devices, link) {
2508 		if (device->context == port->id->verbs) {
2509 			port->device = device;
2510 			break;
2511 		}
2512 	}
2513 	if (!port->device) {
2514 		SPDK_ERRLOG("Accepted a connection with verbs %p, but unable to find a corresponding device.\n",
2515 			    port->id->verbs);
2516 		rdma_destroy_id(port->id);
2517 		free(port);
2518 		pthread_mutex_unlock(&rtransport->lock);
2519 		return -EINVAL;
2520 	}
2521 
2522 	SPDK_INFOLOG(SPDK_LOG_RDMA, "*** NVMf Target Listening on %s port %d ***\n",
2523 		     port->trid.traddr, ntohs(rdma_get_src_port(port->id)));
2524 
2525 	port->ref = 1;
2526 
2527 	TAILQ_INSERT_TAIL(&rtransport->ports, port, link);
2528 	pthread_mutex_unlock(&rtransport->lock);
2529 
2530 	return 0;
2531 }
2532 
2533 static int
2534 spdk_nvmf_rdma_stop_listen(struct spdk_nvmf_transport *transport,
2535 			   const struct spdk_nvme_transport_id *_trid)
2536 {
2537 	struct spdk_nvmf_rdma_transport *rtransport;
2538 	struct spdk_nvmf_rdma_port *port, *tmp;
2539 	struct spdk_nvme_transport_id trid = {};
2540 
2541 	rtransport = SPDK_CONTAINEROF(transport, struct spdk_nvmf_rdma_transport, transport);
2542 
2543 	/* Selectively copy the trid. Things like NQN don't matter here - that
2544 	 * mapping is enforced elsewhere.
2545 	 */
2546 	trid.trtype = SPDK_NVME_TRANSPORT_RDMA;
2547 	trid.adrfam = _trid->adrfam;
2548 	snprintf(trid.traddr, sizeof(port->trid.traddr), "%s", _trid->traddr);
2549 	snprintf(trid.trsvcid, sizeof(port->trid.trsvcid), "%s", _trid->trsvcid);
2550 
2551 	pthread_mutex_lock(&rtransport->lock);
2552 	TAILQ_FOREACH_SAFE(port, &rtransport->ports, link, tmp) {
2553 		if (spdk_nvme_transport_id_compare(&port->trid, &trid) == 0) {
2554 			assert(port->ref > 0);
2555 			port->ref--;
2556 			if (port->ref == 0) {
2557 				TAILQ_REMOVE(&rtransport->ports, port, link);
2558 				rdma_destroy_id(port->id);
2559 				free(port);
2560 			}
2561 			break;
2562 		}
2563 	}
2564 
2565 	pthread_mutex_unlock(&rtransport->lock);
2566 	return 0;
2567 }
2568 
2569 static void
2570 spdk_nvmf_rdma_qpair_process_pending(struct spdk_nvmf_rdma_transport *rtransport,
2571 				     struct spdk_nvmf_rdma_qpair *rqpair, bool drain)
2572 {
2573 	struct spdk_nvmf_rdma_request	*rdma_req, *req_tmp;
2574 	struct spdk_nvmf_rdma_resources *resources;
2575 
2576 	/* We process I/O in the data transfer pending queue at the highest priority. RDMA reads first */
2577 	STAILQ_FOREACH_SAFE(rdma_req, &rqpair->pending_rdma_read_queue, state_link, req_tmp) {
2578 		if (spdk_nvmf_rdma_request_process(rtransport, rdma_req) == false && drain == false) {
2579 			break;
2580 		}
2581 	}
2582 
2583 	/* Then RDMA writes since reads have stronger restrictions than writes */
2584 	STAILQ_FOREACH_SAFE(rdma_req, &rqpair->pending_rdma_write_queue, state_link, req_tmp) {
2585 		if (spdk_nvmf_rdma_request_process(rtransport, rdma_req) == false && drain == false) {
2586 			break;
2587 		}
2588 	}
2589 
2590 	/* The second highest priority is I/O waiting on memory buffers. */
2591 	STAILQ_FOREACH_SAFE(rdma_req, &rqpair->poller->group->pending_data_buf_queue, state_link,
2592 			    req_tmp) {
2593 		if (spdk_nvmf_rdma_request_process(rtransport, rdma_req) == false && drain == false) {
2594 			break;
2595 		}
2596 	}
2597 
2598 	resources = rqpair->resources;
2599 	while (!STAILQ_EMPTY(&resources->free_queue) && !STAILQ_EMPTY(&resources->incoming_queue)) {
2600 		rdma_req = STAILQ_FIRST(&resources->free_queue);
2601 		STAILQ_REMOVE_HEAD(&resources->free_queue, state_link);
2602 		rdma_req->recv = STAILQ_FIRST(&resources->incoming_queue);
2603 		STAILQ_REMOVE_HEAD(&resources->incoming_queue, link);
2604 
2605 		if (rqpair->srq != NULL) {
2606 			rdma_req->req.qpair = &rdma_req->recv->qpair->qpair;
2607 			rdma_req->recv->qpair->qd++;
2608 		} else {
2609 			rqpair->qd++;
2610 		}
2611 
2612 		rdma_req->state = RDMA_REQUEST_STATE_NEW;
2613 		if (spdk_nvmf_rdma_request_process(rtransport, rdma_req) == false) {
2614 			break;
2615 		}
2616 	}
2617 }
2618 
2619 static void
2620 _nvmf_rdma_qpair_disconnect(void *ctx)
2621 {
2622 	struct spdk_nvmf_qpair *qpair = ctx;
2623 
2624 	spdk_nvmf_qpair_disconnect(qpair, NULL, NULL);
2625 }
2626 
2627 static void
2628 _nvmf_rdma_try_disconnect(void *ctx)
2629 {
2630 	struct spdk_nvmf_qpair *qpair = ctx;
2631 	struct spdk_nvmf_poll_group *group;
2632 
2633 	/* Read the group out of the qpair. This is normally set and accessed only from
2634 	 * the thread that created the group. Here, we're not on that thread necessarily.
2635 	 * The data member qpair->group begins it's life as NULL and then is assigned to
2636 	 * a pointer and never changes. So fortunately reading this and checking for
2637 	 * non-NULL is thread safe in the x86_64 memory model. */
2638 	group = qpair->group;
2639 
2640 	if (group == NULL) {
2641 		/* The qpair hasn't been assigned to a group yet, so we can't
2642 		 * process a disconnect. Send a message to ourself and try again. */
2643 		spdk_thread_send_msg(spdk_get_thread(), _nvmf_rdma_try_disconnect, qpair);
2644 		return;
2645 	}
2646 
2647 	spdk_thread_send_msg(group->thread, _nvmf_rdma_qpair_disconnect, qpair);
2648 }
2649 
2650 static inline void
2651 spdk_nvmf_rdma_start_disconnect(struct spdk_nvmf_rdma_qpair *rqpair)
2652 {
2653 	if (__sync_bool_compare_and_swap(&rqpair->disconnect_started, false, true)) {
2654 		_nvmf_rdma_try_disconnect(&rqpair->qpair);
2655 	}
2656 }
2657 
2658 static void nvmf_rdma_destroy_drained_qpair(void *ctx)
2659 {
2660 	struct spdk_nvmf_rdma_qpair *rqpair = ctx;
2661 	struct spdk_nvmf_rdma_transport *rtransport = SPDK_CONTAINEROF(rqpair->qpair.transport,
2662 			struct spdk_nvmf_rdma_transport, transport);
2663 
2664 	/* In non SRQ path, we will reach rqpair->max_queue_depth. In SRQ path, we will get the last_wqe event. */
2665 	if (rqpair->current_send_depth != 0) {
2666 		return;
2667 	}
2668 
2669 	if (rqpair->srq == NULL && rqpair->current_recv_depth != rqpair->max_queue_depth) {
2670 		return;
2671 	}
2672 
2673 	if (rqpair->srq != NULL && rqpair->last_wqe_reached == false) {
2674 		return;
2675 	}
2676 
2677 	spdk_nvmf_rdma_qpair_process_pending(rtransport, rqpair, true);
2678 	spdk_nvmf_rdma_qpair_destroy(rqpair);
2679 }
2680 
2681 
2682 static int
2683 nvmf_rdma_disconnect(struct rdma_cm_event *evt)
2684 {
2685 	struct spdk_nvmf_qpair		*qpair;
2686 	struct spdk_nvmf_rdma_qpair	*rqpair;
2687 
2688 	if (evt->id == NULL) {
2689 		SPDK_ERRLOG("disconnect request: missing cm_id\n");
2690 		return -1;
2691 	}
2692 
2693 	qpair = evt->id->context;
2694 	if (qpair == NULL) {
2695 		SPDK_ERRLOG("disconnect request: no active connection\n");
2696 		return -1;
2697 	}
2698 
2699 	rqpair = SPDK_CONTAINEROF(qpair, struct spdk_nvmf_rdma_qpair, qpair);
2700 
2701 	spdk_trace_record(TRACE_RDMA_QP_DISCONNECT, 0, 0, (uintptr_t)rqpair->cm_id, 0);
2702 
2703 	spdk_nvmf_rdma_update_ibv_state(rqpair);
2704 
2705 	spdk_nvmf_rdma_start_disconnect(rqpair);
2706 
2707 	return 0;
2708 }
2709 
2710 #ifdef DEBUG
2711 static const char *CM_EVENT_STR[] = {
2712 	"RDMA_CM_EVENT_ADDR_RESOLVED",
2713 	"RDMA_CM_EVENT_ADDR_ERROR",
2714 	"RDMA_CM_EVENT_ROUTE_RESOLVED",
2715 	"RDMA_CM_EVENT_ROUTE_ERROR",
2716 	"RDMA_CM_EVENT_CONNECT_REQUEST",
2717 	"RDMA_CM_EVENT_CONNECT_RESPONSE",
2718 	"RDMA_CM_EVENT_CONNECT_ERROR",
2719 	"RDMA_CM_EVENT_UNREACHABLE",
2720 	"RDMA_CM_EVENT_REJECTED",
2721 	"RDMA_CM_EVENT_ESTABLISHED",
2722 	"RDMA_CM_EVENT_DISCONNECTED",
2723 	"RDMA_CM_EVENT_DEVICE_REMOVAL",
2724 	"RDMA_CM_EVENT_MULTICAST_JOIN",
2725 	"RDMA_CM_EVENT_MULTICAST_ERROR",
2726 	"RDMA_CM_EVENT_ADDR_CHANGE",
2727 	"RDMA_CM_EVENT_TIMEWAIT_EXIT"
2728 };
2729 #endif /* DEBUG */
2730 
2731 static void
2732 spdk_nvmf_process_cm_event(struct spdk_nvmf_transport *transport, new_qpair_fn cb_fn)
2733 {
2734 	struct spdk_nvmf_rdma_transport *rtransport;
2735 	struct rdma_cm_event		*event;
2736 	int				rc;
2737 
2738 	rtransport = SPDK_CONTAINEROF(transport, struct spdk_nvmf_rdma_transport, transport);
2739 
2740 	if (rtransport->event_channel == NULL) {
2741 		return;
2742 	}
2743 
2744 	while (1) {
2745 		rc = rdma_get_cm_event(rtransport->event_channel, &event);
2746 		if (rc == 0) {
2747 			SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Acceptor Event: %s\n", CM_EVENT_STR[event->event]);
2748 
2749 			spdk_trace_record(TRACE_RDMA_CM_ASYNC_EVENT, 0, 0, 0, event->event);
2750 
2751 			switch (event->event) {
2752 			case RDMA_CM_EVENT_ADDR_RESOLVED:
2753 			case RDMA_CM_EVENT_ADDR_ERROR:
2754 			case RDMA_CM_EVENT_ROUTE_RESOLVED:
2755 			case RDMA_CM_EVENT_ROUTE_ERROR:
2756 				/* No action required. The target never attempts to resolve routes. */
2757 				break;
2758 			case RDMA_CM_EVENT_CONNECT_REQUEST:
2759 				rc = nvmf_rdma_connect(transport, event, cb_fn);
2760 				if (rc < 0) {
2761 					SPDK_ERRLOG("Unable to process connect event. rc: %d\n", rc);
2762 					break;
2763 				}
2764 				break;
2765 			case RDMA_CM_EVENT_CONNECT_RESPONSE:
2766 				/* The target never initiates a new connection. So this will not occur. */
2767 				break;
2768 			case RDMA_CM_EVENT_CONNECT_ERROR:
2769 				/* Can this happen? The docs say it can, but not sure what causes it. */
2770 				break;
2771 			case RDMA_CM_EVENT_UNREACHABLE:
2772 			case RDMA_CM_EVENT_REJECTED:
2773 				/* These only occur on the client side. */
2774 				break;
2775 			case RDMA_CM_EVENT_ESTABLISHED:
2776 				/* TODO: Should we be waiting for this event anywhere? */
2777 				break;
2778 			case RDMA_CM_EVENT_DISCONNECTED:
2779 			case RDMA_CM_EVENT_DEVICE_REMOVAL:
2780 				rc = nvmf_rdma_disconnect(event);
2781 				if (rc < 0) {
2782 					SPDK_ERRLOG("Unable to process disconnect event. rc: %d\n", rc);
2783 					break;
2784 				}
2785 				break;
2786 			case RDMA_CM_EVENT_MULTICAST_JOIN:
2787 			case RDMA_CM_EVENT_MULTICAST_ERROR:
2788 				/* Multicast is not used */
2789 				break;
2790 			case RDMA_CM_EVENT_ADDR_CHANGE:
2791 				/* Not utilizing this event */
2792 				break;
2793 			case RDMA_CM_EVENT_TIMEWAIT_EXIT:
2794 				/* For now, do nothing. The target never re-uses queue pairs. */
2795 				break;
2796 			default:
2797 				SPDK_ERRLOG("Unexpected Acceptor Event [%d]\n", event->event);
2798 				break;
2799 			}
2800 
2801 			rdma_ack_cm_event(event);
2802 		} else {
2803 			if (errno != EAGAIN && errno != EWOULDBLOCK) {
2804 				SPDK_ERRLOG("Acceptor Event Error: %s\n", spdk_strerror(errno));
2805 			}
2806 			break;
2807 		}
2808 	}
2809 }
2810 
2811 static void
2812 spdk_nvmf_process_ib_event(struct spdk_nvmf_rdma_device *device)
2813 {
2814 	int				rc;
2815 	struct spdk_nvmf_rdma_qpair	*rqpair = NULL;
2816 	struct ibv_async_event		event;
2817 	enum ibv_qp_state		state;
2818 
2819 	rc = ibv_get_async_event(device->context, &event);
2820 
2821 	if (rc) {
2822 		SPDK_ERRLOG("Failed to get async_event (%d): %s\n",
2823 			    errno, spdk_strerror(errno));
2824 		return;
2825 	}
2826 
2827 	switch (event.event_type) {
2828 	case IBV_EVENT_QP_FATAL:
2829 		rqpair = event.element.qp->qp_context;
2830 		SPDK_ERRLOG("Fatal event received for rqpair %p\n", rqpair);
2831 		spdk_trace_record(TRACE_RDMA_IBV_ASYNC_EVENT, 0, 0,
2832 				  (uintptr_t)rqpair->cm_id, event.event_type);
2833 		spdk_nvmf_rdma_update_ibv_state(rqpair);
2834 		spdk_nvmf_rdma_start_disconnect(rqpair);
2835 		break;
2836 	case IBV_EVENT_QP_LAST_WQE_REACHED:
2837 		/* This event only occurs for shared receive queues. */
2838 		rqpair = event.element.qp->qp_context;
2839 		rqpair->last_wqe_reached = true;
2840 
2841 		SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Last WQE reached event received for rqpair %p\n", rqpair);
2842 		/* This must be handled on the polling thread if it exists. Otherwise the timeout will catch it. */
2843 		if (rqpair->qpair.group) {
2844 			spdk_thread_send_msg(rqpair->qpair.group->thread, nvmf_rdma_destroy_drained_qpair, rqpair);
2845 		} else {
2846 			SPDK_ERRLOG("Unable to destroy the qpair %p since it does not have a poll group.\n", rqpair);
2847 		}
2848 
2849 		break;
2850 	case IBV_EVENT_SQ_DRAINED:
2851 		/* This event occurs frequently in both error and non-error states.
2852 		 * Check if the qpair is in an error state before sending a message.
2853 		 * Note that we're not on the correct thread to access the qpair, but
2854 		 * the operations that the below calls make all happen to be thread
2855 		 * safe. */
2856 		rqpair = event.element.qp->qp_context;
2857 		SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Last sq drained event received for rqpair %p\n", rqpair);
2858 		spdk_trace_record(TRACE_RDMA_IBV_ASYNC_EVENT, 0, 0,
2859 				  (uintptr_t)rqpair->cm_id, event.event_type);
2860 		state = spdk_nvmf_rdma_update_ibv_state(rqpair);
2861 		if (state == IBV_QPS_ERR) {
2862 			spdk_nvmf_rdma_start_disconnect(rqpair);
2863 		}
2864 		break;
2865 	case IBV_EVENT_QP_REQ_ERR:
2866 	case IBV_EVENT_QP_ACCESS_ERR:
2867 	case IBV_EVENT_COMM_EST:
2868 	case IBV_EVENT_PATH_MIG:
2869 	case IBV_EVENT_PATH_MIG_ERR:
2870 		SPDK_NOTICELOG("Async event: %s\n",
2871 			       ibv_event_type_str(event.event_type));
2872 		rqpair = event.element.qp->qp_context;
2873 		spdk_trace_record(TRACE_RDMA_IBV_ASYNC_EVENT, 0, 0,
2874 				  (uintptr_t)rqpair->cm_id, event.event_type);
2875 		spdk_nvmf_rdma_update_ibv_state(rqpair);
2876 		break;
2877 	case IBV_EVENT_CQ_ERR:
2878 	case IBV_EVENT_DEVICE_FATAL:
2879 	case IBV_EVENT_PORT_ACTIVE:
2880 	case IBV_EVENT_PORT_ERR:
2881 	case IBV_EVENT_LID_CHANGE:
2882 	case IBV_EVENT_PKEY_CHANGE:
2883 	case IBV_EVENT_SM_CHANGE:
2884 	case IBV_EVENT_SRQ_ERR:
2885 	case IBV_EVENT_SRQ_LIMIT_REACHED:
2886 	case IBV_EVENT_CLIENT_REREGISTER:
2887 	case IBV_EVENT_GID_CHANGE:
2888 	default:
2889 		SPDK_NOTICELOG("Async event: %s\n",
2890 			       ibv_event_type_str(event.event_type));
2891 		spdk_trace_record(TRACE_RDMA_IBV_ASYNC_EVENT, 0, 0, 0, event.event_type);
2892 		break;
2893 	}
2894 	ibv_ack_async_event(&event);
2895 }
2896 
2897 static void
2898 spdk_nvmf_rdma_accept(struct spdk_nvmf_transport *transport, new_qpair_fn cb_fn)
2899 {
2900 	int	nfds, i = 0;
2901 	struct spdk_nvmf_rdma_transport *rtransport;
2902 	struct spdk_nvmf_rdma_device *device, *tmp;
2903 
2904 	rtransport = SPDK_CONTAINEROF(transport, struct spdk_nvmf_rdma_transport, transport);
2905 	nfds = poll(rtransport->poll_fds, rtransport->npoll_fds, 0);
2906 
2907 	if (nfds <= 0) {
2908 		return;
2909 	}
2910 
2911 	/* The first poll descriptor is RDMA CM event */
2912 	if (rtransport->poll_fds[i++].revents & POLLIN) {
2913 		spdk_nvmf_process_cm_event(transport, cb_fn);
2914 		nfds--;
2915 	}
2916 
2917 	if (nfds == 0) {
2918 		return;
2919 	}
2920 
2921 	/* Second and subsequent poll descriptors are IB async events */
2922 	TAILQ_FOREACH_SAFE(device, &rtransport->devices, link, tmp) {
2923 		if (rtransport->poll_fds[i++].revents & POLLIN) {
2924 			spdk_nvmf_process_ib_event(device);
2925 			nfds--;
2926 		}
2927 	}
2928 	/* check all flagged fd's have been served */
2929 	assert(nfds == 0);
2930 }
2931 
2932 static void
2933 spdk_nvmf_rdma_discover(struct spdk_nvmf_transport *transport,
2934 			struct spdk_nvme_transport_id *trid,
2935 			struct spdk_nvmf_discovery_log_page_entry *entry)
2936 {
2937 	entry->trtype = SPDK_NVMF_TRTYPE_RDMA;
2938 	entry->adrfam = trid->adrfam;
2939 	entry->treq.secure_channel = SPDK_NVMF_TREQ_SECURE_CHANNEL_NOT_SPECIFIED;
2940 
2941 	spdk_strcpy_pad(entry->trsvcid, trid->trsvcid, sizeof(entry->trsvcid), ' ');
2942 	spdk_strcpy_pad(entry->traddr, trid->traddr, sizeof(entry->traddr), ' ');
2943 
2944 	entry->tsas.rdma.rdma_qptype = SPDK_NVMF_RDMA_QPTYPE_RELIABLE_CONNECTED;
2945 	entry->tsas.rdma.rdma_prtype = SPDK_NVMF_RDMA_PRTYPE_NONE;
2946 	entry->tsas.rdma.rdma_cms = SPDK_NVMF_RDMA_CMS_RDMA_CM;
2947 }
2948 
2949 static void
2950 spdk_nvmf_rdma_poll_group_destroy(struct spdk_nvmf_transport_poll_group *group);
2951 
2952 static struct spdk_nvmf_transport_poll_group *
2953 spdk_nvmf_rdma_poll_group_create(struct spdk_nvmf_transport *transport)
2954 {
2955 	struct spdk_nvmf_rdma_transport		*rtransport;
2956 	struct spdk_nvmf_rdma_poll_group	*rgroup;
2957 	struct spdk_nvmf_rdma_poller		*poller;
2958 	struct spdk_nvmf_rdma_device		*device;
2959 	struct ibv_srq_init_attr		srq_init_attr;
2960 	struct spdk_nvmf_rdma_resource_opts	opts;
2961 	int					num_cqe;
2962 
2963 	rtransport = SPDK_CONTAINEROF(transport, struct spdk_nvmf_rdma_transport, transport);
2964 
2965 	rgroup = calloc(1, sizeof(*rgroup));
2966 	if (!rgroup) {
2967 		return NULL;
2968 	}
2969 
2970 	TAILQ_INIT(&rgroup->pollers);
2971 	STAILQ_INIT(&rgroup->pending_data_buf_queue);
2972 
2973 	pthread_mutex_lock(&rtransport->lock);
2974 	TAILQ_FOREACH(device, &rtransport->devices, link) {
2975 		poller = calloc(1, sizeof(*poller));
2976 		if (!poller) {
2977 			SPDK_ERRLOG("Unable to allocate memory for new RDMA poller\n");
2978 			spdk_nvmf_rdma_poll_group_destroy(&rgroup->group);
2979 			pthread_mutex_unlock(&rtransport->lock);
2980 			return NULL;
2981 		}
2982 
2983 		poller->device = device;
2984 		poller->group = rgroup;
2985 
2986 		TAILQ_INIT(&poller->qpairs);
2987 		STAILQ_INIT(&poller->qpairs_pending_send);
2988 		STAILQ_INIT(&poller->qpairs_pending_recv);
2989 
2990 		TAILQ_INSERT_TAIL(&rgroup->pollers, poller, link);
2991 		if (transport->opts.no_srq == false && device->attr.max_srq != 0) {
2992 			poller->max_srq_depth = transport->opts.max_srq_depth;
2993 
2994 			memset(&srq_init_attr, 0, sizeof(struct ibv_srq_init_attr));
2995 			srq_init_attr.attr.max_wr = poller->max_srq_depth;
2996 			srq_init_attr.attr.max_sge = spdk_min(device->attr.max_sge, NVMF_DEFAULT_RX_SGE);
2997 			poller->srq = ibv_create_srq(device->pd, &srq_init_attr);
2998 			if (!poller->srq) {
2999 				SPDK_ERRLOG("Unable to create shared receive queue, errno %d\n", errno);
3000 				spdk_nvmf_rdma_poll_group_destroy(&rgroup->group);
3001 				pthread_mutex_unlock(&rtransport->lock);
3002 				return NULL;
3003 			}
3004 
3005 			opts.qp = poller->srq;
3006 			opts.pd = device->pd;
3007 			opts.qpair = NULL;
3008 			opts.shared = true;
3009 			opts.max_queue_depth = poller->max_srq_depth;
3010 			opts.in_capsule_data_size = transport->opts.in_capsule_data_size;
3011 
3012 			poller->resources = nvmf_rdma_resources_create(&opts);
3013 			if (!poller->resources) {
3014 				SPDK_ERRLOG("Unable to allocate resources for shared receive queue.\n");
3015 				spdk_nvmf_rdma_poll_group_destroy(&rgroup->group);
3016 				pthread_mutex_unlock(&rtransport->lock);
3017 			}
3018 		}
3019 
3020 		/*
3021 		 * When using an srq, we can limit the completion queue at startup.
3022 		 * The following formula represents the calculation:
3023 		 * num_cqe = num_recv + num_data_wr + num_send_wr.
3024 		 * where num_recv=num_data_wr=and num_send_wr=poller->max_srq_depth
3025 		 */
3026 		if (poller->srq) {
3027 			num_cqe = poller->max_srq_depth * 3;
3028 		} else {
3029 			num_cqe = DEFAULT_NVMF_RDMA_CQ_SIZE;
3030 		}
3031 
3032 		poller->cq = ibv_create_cq(device->context, num_cqe, poller, NULL, 0);
3033 		if (!poller->cq) {
3034 			SPDK_ERRLOG("Unable to create completion queue\n");
3035 			spdk_nvmf_rdma_poll_group_destroy(&rgroup->group);
3036 			pthread_mutex_unlock(&rtransport->lock);
3037 			return NULL;
3038 		}
3039 		poller->num_cqe = num_cqe;
3040 	}
3041 
3042 	pthread_mutex_unlock(&rtransport->lock);
3043 	return &rgroup->group;
3044 }
3045 
3046 static void
3047 spdk_nvmf_rdma_poll_group_destroy(struct spdk_nvmf_transport_poll_group *group)
3048 {
3049 	struct spdk_nvmf_rdma_poll_group	*rgroup;
3050 	struct spdk_nvmf_rdma_poller		*poller, *tmp;
3051 	struct spdk_nvmf_rdma_qpair		*qpair, *tmp_qpair;
3052 
3053 	rgroup = SPDK_CONTAINEROF(group, struct spdk_nvmf_rdma_poll_group, group);
3054 
3055 	if (!rgroup) {
3056 		return;
3057 	}
3058 
3059 	TAILQ_FOREACH_SAFE(poller, &rgroup->pollers, link, tmp) {
3060 		TAILQ_REMOVE(&rgroup->pollers, poller, link);
3061 
3062 		TAILQ_FOREACH_SAFE(qpair, &poller->qpairs, link, tmp_qpair) {
3063 			spdk_nvmf_rdma_qpair_destroy(qpair);
3064 		}
3065 
3066 		if (poller->srq) {
3067 			nvmf_rdma_resources_destroy(poller->resources);
3068 			ibv_destroy_srq(poller->srq);
3069 			SPDK_DEBUGLOG(SPDK_LOG_RDMA, "Destroyed RDMA shared queue %p\n", poller->srq);
3070 		}
3071 
3072 		if (poller->cq) {
3073 			ibv_destroy_cq(poller->cq);
3074 		}
3075 
3076 		free(poller);
3077 	}
3078 
3079 	if (!STAILQ_EMPTY(&rgroup->pending_data_buf_queue)) {
3080 		SPDK_ERRLOG("Pending I/O list wasn't empty on poll group destruction\n");
3081 	}
3082 
3083 	free(rgroup);
3084 }
3085 
3086 static void
3087 spdk_nvmf_rdma_qpair_reject_connection(struct spdk_nvmf_rdma_qpair *rqpair)
3088 {
3089 	if (rqpair->cm_id != NULL) {
3090 		spdk_nvmf_rdma_event_reject(rqpair->cm_id, SPDK_NVMF_RDMA_ERROR_NO_RESOURCES);
3091 	}
3092 	spdk_nvmf_rdma_qpair_destroy(rqpair);
3093 }
3094 
3095 static int
3096 spdk_nvmf_rdma_poll_group_add(struct spdk_nvmf_transport_poll_group *group,
3097 			      struct spdk_nvmf_qpair *qpair)
3098 {
3099 	struct spdk_nvmf_rdma_poll_group	*rgroup;
3100 	struct spdk_nvmf_rdma_qpair		*rqpair;
3101 	struct spdk_nvmf_rdma_device		*device;
3102 	struct spdk_nvmf_rdma_poller		*poller;
3103 	int					rc;
3104 
3105 	rgroup = SPDK_CONTAINEROF(group, struct spdk_nvmf_rdma_poll_group, group);
3106 	rqpair = SPDK_CONTAINEROF(qpair, struct spdk_nvmf_rdma_qpair, qpair);
3107 
3108 	device = rqpair->port->device;
3109 
3110 	TAILQ_FOREACH(poller, &rgroup->pollers, link) {
3111 		if (poller->device == device) {
3112 			break;
3113 		}
3114 	}
3115 
3116 	if (!poller) {
3117 		SPDK_ERRLOG("No poller found for device.\n");
3118 		return -1;
3119 	}
3120 
3121 	TAILQ_INSERT_TAIL(&poller->qpairs, rqpair, link);
3122 	rqpair->poller = poller;
3123 	rqpair->srq = rqpair->poller->srq;
3124 
3125 	rc = spdk_nvmf_rdma_qpair_initialize(qpair);
3126 	if (rc < 0) {
3127 		SPDK_ERRLOG("Failed to initialize nvmf_rdma_qpair with qpair=%p\n", qpair);
3128 		return -1;
3129 	}
3130 
3131 	rc = spdk_nvmf_rdma_event_accept(rqpair->cm_id, rqpair);
3132 	if (rc) {
3133 		/* Try to reject, but we probably can't */
3134 		spdk_nvmf_rdma_qpair_reject_connection(rqpair);
3135 		return -1;
3136 	}
3137 
3138 	spdk_nvmf_rdma_update_ibv_state(rqpair);
3139 
3140 	return 0;
3141 }
3142 
3143 static int
3144 spdk_nvmf_rdma_request_free(struct spdk_nvmf_request *req)
3145 {
3146 	struct spdk_nvmf_rdma_request	*rdma_req = SPDK_CONTAINEROF(req, struct spdk_nvmf_rdma_request, req);
3147 	struct spdk_nvmf_rdma_transport	*rtransport = SPDK_CONTAINEROF(req->qpair->transport,
3148 			struct spdk_nvmf_rdma_transport, transport);
3149 
3150 	nvmf_rdma_request_free(rdma_req, rtransport);
3151 	return 0;
3152 }
3153 
3154 static int
3155 spdk_nvmf_rdma_request_complete(struct spdk_nvmf_request *req)
3156 {
3157 	struct spdk_nvmf_rdma_transport	*rtransport = SPDK_CONTAINEROF(req->qpair->transport,
3158 			struct spdk_nvmf_rdma_transport, transport);
3159 	struct spdk_nvmf_rdma_request	*rdma_req = SPDK_CONTAINEROF(req,
3160 			struct spdk_nvmf_rdma_request, req);
3161 	struct spdk_nvmf_rdma_qpair     *rqpair = SPDK_CONTAINEROF(rdma_req->req.qpair,
3162 			struct spdk_nvmf_rdma_qpair, qpair);
3163 
3164 	if (rqpair->ibv_state != IBV_QPS_ERR) {
3165 		/* The connection is alive, so process the request as normal */
3166 		rdma_req->state = RDMA_REQUEST_STATE_EXECUTED;
3167 	} else {
3168 		/* The connection is dead. Move the request directly to the completed state. */
3169 		rdma_req->state = RDMA_REQUEST_STATE_COMPLETED;
3170 	}
3171 
3172 	spdk_nvmf_rdma_request_process(rtransport, rdma_req);
3173 
3174 	return 0;
3175 }
3176 
3177 static int
3178 spdk_nvmf_rdma_destroy_defunct_qpair(void *ctx)
3179 {
3180 	struct spdk_nvmf_rdma_qpair	*rqpair = ctx;
3181 	struct spdk_nvmf_rdma_transport *rtransport = SPDK_CONTAINEROF(rqpair->qpair.transport,
3182 			struct spdk_nvmf_rdma_transport, transport);
3183 
3184 	spdk_nvmf_rdma_qpair_process_pending(rtransport, rqpair, true);
3185 	spdk_nvmf_rdma_qpair_destroy(rqpair);
3186 
3187 	return 0;
3188 }
3189 
3190 static void
3191 spdk_nvmf_rdma_close_qpair(struct spdk_nvmf_qpair *qpair)
3192 {
3193 	struct spdk_nvmf_rdma_qpair *rqpair = SPDK_CONTAINEROF(qpair, struct spdk_nvmf_rdma_qpair, qpair);
3194 
3195 	if (rqpair->disconnect_flags & RDMA_QP_DISCONNECTING) {
3196 		return;
3197 	}
3198 
3199 	rqpair->disconnect_flags |= RDMA_QP_DISCONNECTING;
3200 
3201 	/* This happens only when the qpair is disconnected before
3202 	 * it is added to the poll group. Since there is no poll group,
3203 	 * the RDMA qp has not been initialized yet and the RDMA CM
3204 	 * event has not yet been acknowledged, so we need to reject it.
3205 	 */
3206 	if (rqpair->qpair.state == SPDK_NVMF_QPAIR_UNINITIALIZED) {
3207 		spdk_nvmf_rdma_qpair_reject_connection(rqpair);
3208 		return;
3209 	}
3210 
3211 	if (rqpair->ibv_state != IBV_QPS_ERR) {
3212 		spdk_nvmf_rdma_set_ibv_state(rqpair, IBV_QPS_ERR);
3213 	}
3214 
3215 	rqpair->destruct_poller = spdk_poller_register(spdk_nvmf_rdma_destroy_defunct_qpair, (void *)rqpair,
3216 				  NVMF_RDMA_QPAIR_DESTROY_TIMEOUT_US);
3217 }
3218 
3219 static struct spdk_nvmf_rdma_qpair *
3220 get_rdma_qpair_from_wc(struct spdk_nvmf_rdma_poller *rpoller, struct ibv_wc *wc)
3221 {
3222 	struct spdk_nvmf_rdma_qpair *rqpair;
3223 	/* @todo: improve QP search */
3224 	TAILQ_FOREACH(rqpair, &rpoller->qpairs, link) {
3225 		if (wc->qp_num == rqpair->cm_id->qp->qp_num) {
3226 			return rqpair;
3227 		}
3228 	}
3229 	SPDK_ERRLOG("Didn't find QP with qp_num %u\n", wc->qp_num);
3230 	return NULL;
3231 }
3232 
3233 #ifdef DEBUG
3234 static int
3235 spdk_nvmf_rdma_req_is_completing(struct spdk_nvmf_rdma_request *rdma_req)
3236 {
3237 	return rdma_req->state == RDMA_REQUEST_STATE_TRANSFERRING_CONTROLLER_TO_HOST ||
3238 	       rdma_req->state == RDMA_REQUEST_STATE_COMPLETING;
3239 }
3240 #endif
3241 
3242 static void
3243 _poller_reset_failed_recvs(struct spdk_nvmf_rdma_poller *rpoller, struct ibv_recv_wr *bad_recv_wr,
3244 			   int rc)
3245 {
3246 	struct spdk_nvmf_rdma_recv	*rdma_recv;
3247 	struct spdk_nvmf_rdma_wr	*bad_rdma_wr;
3248 
3249 	SPDK_ERRLOG("Failed to post a recv for the poller %p with errno %d\n", rpoller, -rc);
3250 	while (bad_recv_wr != NULL) {
3251 		bad_rdma_wr = (struct spdk_nvmf_rdma_wr *)bad_recv_wr->wr_id;
3252 		rdma_recv = SPDK_CONTAINEROF(bad_rdma_wr, struct spdk_nvmf_rdma_recv, rdma_wr);
3253 
3254 		rdma_recv->qpair->current_recv_depth++;
3255 		bad_recv_wr = bad_recv_wr->next;
3256 		SPDK_ERRLOG("Failed to post a recv for the qpair %p with errno %d\n", rdma_recv->qpair, -rc);
3257 		spdk_nvmf_rdma_start_disconnect(rdma_recv->qpair);
3258 	}
3259 }
3260 
3261 static void
3262 _qp_reset_failed_recvs(struct spdk_nvmf_rdma_qpair *rqpair, struct ibv_recv_wr *bad_recv_wr, int rc)
3263 {
3264 	SPDK_ERRLOG("Failed to post a recv for the qpair %p with errno %d\n", rqpair, -rc);
3265 	while (bad_recv_wr != NULL) {
3266 		bad_recv_wr = bad_recv_wr->next;
3267 		rqpair->current_recv_depth++;
3268 	}
3269 	spdk_nvmf_rdma_start_disconnect(rqpair);
3270 }
3271 
3272 static void
3273 _poller_submit_recvs(struct spdk_nvmf_rdma_transport *rtransport,
3274 		     struct spdk_nvmf_rdma_poller *rpoller)
3275 {
3276 	struct spdk_nvmf_rdma_qpair	*rqpair;
3277 	struct ibv_recv_wr		*bad_recv_wr;
3278 	int				rc;
3279 
3280 	if (rpoller->srq) {
3281 		if (rpoller->resources->recvs_to_post.first != NULL) {
3282 			rc = ibv_post_srq_recv(rpoller->srq, rpoller->resources->recvs_to_post.first, &bad_recv_wr);
3283 			if (rc) {
3284 				_poller_reset_failed_recvs(rpoller, bad_recv_wr, rc);
3285 			}
3286 			rpoller->resources->recvs_to_post.first = NULL;
3287 			rpoller->resources->recvs_to_post.last = NULL;
3288 		}
3289 	} else {
3290 		while (!STAILQ_EMPTY(&rpoller->qpairs_pending_recv)) {
3291 			rqpair = STAILQ_FIRST(&rpoller->qpairs_pending_recv);
3292 			assert(rqpair->resources->recvs_to_post.first != NULL);
3293 			rc = ibv_post_recv(rqpair->cm_id->qp, rqpair->resources->recvs_to_post.first, &bad_recv_wr);
3294 			if (rc) {
3295 				_qp_reset_failed_recvs(rqpair, bad_recv_wr, rc);
3296 			}
3297 			rqpair->resources->recvs_to_post.first = NULL;
3298 			rqpair->resources->recvs_to_post.last = NULL;
3299 			STAILQ_REMOVE_HEAD(&rpoller->qpairs_pending_recv, recv_link);
3300 		}
3301 	}
3302 }
3303 
3304 static void
3305 _qp_reset_failed_sends(struct spdk_nvmf_rdma_transport *rtransport,
3306 		       struct spdk_nvmf_rdma_qpair *rqpair, struct ibv_send_wr *bad_wr, int rc)
3307 {
3308 	struct spdk_nvmf_rdma_wr	*bad_rdma_wr;
3309 	struct spdk_nvmf_rdma_request	*prev_rdma_req = NULL, *cur_rdma_req = NULL;
3310 
3311 	SPDK_ERRLOG("Failed to post a send for the qpair %p with errno %d\n", rqpair, -rc);
3312 	for (; bad_wr != NULL; bad_wr = bad_wr->next) {
3313 		bad_rdma_wr = (struct spdk_nvmf_rdma_wr *)bad_wr->wr_id;
3314 		assert(rqpair->current_send_depth > 0);
3315 		rqpair->current_send_depth--;
3316 		switch (bad_rdma_wr->type) {
3317 		case RDMA_WR_TYPE_DATA:
3318 			cur_rdma_req = SPDK_CONTAINEROF(bad_rdma_wr, struct spdk_nvmf_rdma_request, data.rdma_wr);
3319 			if (bad_wr->opcode == IBV_WR_RDMA_READ) {
3320 				assert(rqpair->current_read_depth > 0);
3321 				rqpair->current_read_depth--;
3322 			}
3323 			break;
3324 		case RDMA_WR_TYPE_SEND:
3325 			cur_rdma_req = SPDK_CONTAINEROF(bad_rdma_wr, struct spdk_nvmf_rdma_request, rsp.rdma_wr);
3326 			break;
3327 		default:
3328 			SPDK_ERRLOG("Found a RECV in the list of pending SEND requests for qpair %p\n", rqpair);
3329 			prev_rdma_req = cur_rdma_req;
3330 			continue;
3331 		}
3332 
3333 		if (prev_rdma_req == cur_rdma_req) {
3334 			/* this request was handled by an earlier wr. i.e. we were performing an nvme read. */
3335 			/* We only have to check against prev_wr since each requests wrs are contiguous in this list. */
3336 			continue;
3337 		}
3338 
3339 		switch (cur_rdma_req->state) {
3340 		case RDMA_REQUEST_STATE_TRANSFERRING_HOST_TO_CONTROLLER:
3341 			cur_rdma_req->req.rsp->nvme_cpl.status.sc = SPDK_NVME_SC_INTERNAL_DEVICE_ERROR;
3342 			cur_rdma_req->state = RDMA_REQUEST_STATE_READY_TO_COMPLETE;
3343 			break;
3344 		case RDMA_REQUEST_STATE_TRANSFERRING_CONTROLLER_TO_HOST:
3345 		case RDMA_REQUEST_STATE_COMPLETING:
3346 			cur_rdma_req->state = RDMA_REQUEST_STATE_COMPLETED;
3347 			break;
3348 		default:
3349 			SPDK_ERRLOG("Found a request in a bad state %d when draining pending SEND requests for qpair %p\n",
3350 				    cur_rdma_req->state, rqpair);
3351 			continue;
3352 		}
3353 
3354 		spdk_nvmf_rdma_request_process(rtransport, cur_rdma_req);
3355 		prev_rdma_req = cur_rdma_req;
3356 	}
3357 
3358 	if (rqpair->qpair.state == SPDK_NVMF_QPAIR_ACTIVE) {
3359 		/* Disconnect the connection. */
3360 		spdk_nvmf_rdma_start_disconnect(rqpair);
3361 	}
3362 
3363 }
3364 
3365 static void
3366 _poller_submit_sends(struct spdk_nvmf_rdma_transport *rtransport,
3367 		     struct spdk_nvmf_rdma_poller *rpoller)
3368 {
3369 	struct spdk_nvmf_rdma_qpair	*rqpair;
3370 	struct ibv_send_wr		*bad_wr = NULL;
3371 	int				rc;
3372 
3373 	while (!STAILQ_EMPTY(&rpoller->qpairs_pending_send)) {
3374 		rqpair = STAILQ_FIRST(&rpoller->qpairs_pending_send);
3375 		assert(rqpair->sends_to_post.first != NULL);
3376 		rc = ibv_post_send(rqpair->cm_id->qp, rqpair->sends_to_post.first, &bad_wr);
3377 
3378 		/* bad wr always points to the first wr that failed. */
3379 		if (rc) {
3380 			_qp_reset_failed_sends(rtransport, rqpair, bad_wr, rc);
3381 		}
3382 		rqpair->sends_to_post.first = NULL;
3383 		rqpair->sends_to_post.last = NULL;
3384 		STAILQ_REMOVE_HEAD(&rpoller->qpairs_pending_send, send_link);
3385 	}
3386 }
3387 
3388 static int
3389 spdk_nvmf_rdma_poller_poll(struct spdk_nvmf_rdma_transport *rtransport,
3390 			   struct spdk_nvmf_rdma_poller *rpoller)
3391 {
3392 	struct ibv_wc wc[32];
3393 	struct spdk_nvmf_rdma_wr	*rdma_wr;
3394 	struct spdk_nvmf_rdma_request	*rdma_req;
3395 	struct spdk_nvmf_rdma_recv	*rdma_recv;
3396 	struct spdk_nvmf_rdma_qpair	*rqpair;
3397 	int reaped, i;
3398 	int count = 0;
3399 	bool error = false;
3400 
3401 	/* Poll for completing operations. */
3402 	reaped = ibv_poll_cq(rpoller->cq, 32, wc);
3403 	if (reaped < 0) {
3404 		SPDK_ERRLOG("Error polling CQ! (%d): %s\n",
3405 			    errno, spdk_strerror(errno));
3406 		return -1;
3407 	}
3408 
3409 	for (i = 0; i < reaped; i++) {
3410 
3411 		rdma_wr = (struct spdk_nvmf_rdma_wr *)wc[i].wr_id;
3412 
3413 		switch (rdma_wr->type) {
3414 		case RDMA_WR_TYPE_SEND:
3415 			rdma_req = SPDK_CONTAINEROF(rdma_wr, struct spdk_nvmf_rdma_request, rsp.rdma_wr);
3416 			rqpair = SPDK_CONTAINEROF(rdma_req->req.qpair, struct spdk_nvmf_rdma_qpair, qpair);
3417 
3418 			if (!wc[i].status) {
3419 				count++;
3420 				assert(wc[i].opcode == IBV_WC_SEND);
3421 				assert(spdk_nvmf_rdma_req_is_completing(rdma_req));
3422 			} else {
3423 				SPDK_ERRLOG("data=%p length=%u\n", rdma_req->req.data, rdma_req->req.length);
3424 			}
3425 
3426 			rdma_req->state = RDMA_REQUEST_STATE_COMPLETED;
3427 			rqpair->current_send_depth--;
3428 
3429 			spdk_nvmf_rdma_request_process(rtransport, rdma_req);
3430 			assert(rdma_req->num_outstanding_data_wr == 0);
3431 			break;
3432 		case RDMA_WR_TYPE_RECV:
3433 			/* rdma_recv->qpair will be invalid if using an SRQ.  In that case we have to get the qpair from the wc. */
3434 			rdma_recv = SPDK_CONTAINEROF(rdma_wr, struct spdk_nvmf_rdma_recv, rdma_wr);
3435 			if (rpoller->srq != NULL) {
3436 				rdma_recv->qpair = get_rdma_qpair_from_wc(rpoller, &wc[i]);
3437 			}
3438 			rqpair = rdma_recv->qpair;
3439 
3440 			assert(rqpair != NULL);
3441 			if (!wc[i].status) {
3442 				assert(wc[i].opcode == IBV_WC_RECV);
3443 				if (rqpair->current_recv_depth >= rqpair->max_queue_depth) {
3444 					spdk_nvmf_rdma_start_disconnect(rqpair);
3445 					break;
3446 				}
3447 			}
3448 
3449 			rdma_recv->wr.next = NULL;
3450 			rqpair->current_recv_depth++;
3451 			STAILQ_INSERT_TAIL(&rqpair->resources->incoming_queue, rdma_recv, link);
3452 			break;
3453 		case RDMA_WR_TYPE_DATA:
3454 			rdma_req = SPDK_CONTAINEROF(rdma_wr, struct spdk_nvmf_rdma_request, data.rdma_wr);
3455 			rqpair = SPDK_CONTAINEROF(rdma_req->req.qpair, struct spdk_nvmf_rdma_qpair, qpair);
3456 
3457 			assert(rdma_req->num_outstanding_data_wr > 0);
3458 
3459 			rqpair->current_send_depth--;
3460 			rdma_req->num_outstanding_data_wr--;
3461 			if (!wc[i].status) {
3462 				if (wc[i].opcode == IBV_WC_RDMA_READ) {
3463 					rqpair->current_read_depth--;
3464 					/* wait for all outstanding reads associated with the same rdma_req to complete before proceeding. */
3465 					if (rdma_req->num_outstanding_data_wr == 0) {
3466 						rdma_req->state = RDMA_REQUEST_STATE_READY_TO_EXECUTE;
3467 						spdk_nvmf_rdma_request_process(rtransport, rdma_req);
3468 					}
3469 				} else {
3470 					assert(wc[i].opcode == IBV_WC_RDMA_WRITE);
3471 				}
3472 			} else {
3473 				/* If the data transfer fails still force the queue into the error state,
3474 				 * if we were performing an RDMA_READ, we need to force the request into a
3475 				 * completed state since it wasn't linked to a send. However, in the RDMA_WRITE
3476 				 * case, we should wait for the SEND to complete. */
3477 				SPDK_ERRLOG("data=%p length=%u\n", rdma_req->req.data, rdma_req->req.length);
3478 				if (rdma_req->data.wr.opcode == IBV_WR_RDMA_READ) {
3479 					rqpair->current_read_depth--;
3480 					if (rdma_req->num_outstanding_data_wr == 0) {
3481 						rdma_req->state = RDMA_REQUEST_STATE_COMPLETED;
3482 					}
3483 				}
3484 			}
3485 			break;
3486 		default:
3487 			SPDK_ERRLOG("Received an unknown opcode on the CQ: %d\n", wc[i].opcode);
3488 			continue;
3489 		}
3490 
3491 		/* Handle error conditions */
3492 		if (wc[i].status) {
3493 			SPDK_DEBUGLOG(SPDK_LOG_RDMA, "CQ error on CQ %p, Request 0x%lu (%d): %s\n",
3494 				      rpoller->cq, wc[i].wr_id, wc[i].status, ibv_wc_status_str(wc[i].status));
3495 
3496 			error = true;
3497 
3498 			if (rqpair->qpair.state == SPDK_NVMF_QPAIR_ACTIVE) {
3499 				/* Disconnect the connection. */
3500 				spdk_nvmf_rdma_start_disconnect(rqpair);
3501 			} else {
3502 				nvmf_rdma_destroy_drained_qpair(rqpair);
3503 			}
3504 			continue;
3505 		}
3506 
3507 		spdk_nvmf_rdma_qpair_process_pending(rtransport, rqpair, false);
3508 
3509 		if (rqpair->qpair.state != SPDK_NVMF_QPAIR_ACTIVE) {
3510 			nvmf_rdma_destroy_drained_qpair(rqpair);
3511 		}
3512 	}
3513 
3514 	if (error == true) {
3515 		return -1;
3516 	}
3517 
3518 	/* submit outstanding work requests. */
3519 	_poller_submit_recvs(rtransport, rpoller);
3520 	_poller_submit_sends(rtransport, rpoller);
3521 
3522 	return count;
3523 }
3524 
3525 static int
3526 spdk_nvmf_rdma_poll_group_poll(struct spdk_nvmf_transport_poll_group *group)
3527 {
3528 	struct spdk_nvmf_rdma_transport *rtransport;
3529 	struct spdk_nvmf_rdma_poll_group *rgroup;
3530 	struct spdk_nvmf_rdma_poller	*rpoller;
3531 	int				count, rc;
3532 
3533 	rtransport = SPDK_CONTAINEROF(group->transport, struct spdk_nvmf_rdma_transport, transport);
3534 	rgroup = SPDK_CONTAINEROF(group, struct spdk_nvmf_rdma_poll_group, group);
3535 
3536 	count = 0;
3537 	TAILQ_FOREACH(rpoller, &rgroup->pollers, link) {
3538 		rc = spdk_nvmf_rdma_poller_poll(rtransport, rpoller);
3539 		if (rc < 0) {
3540 			return rc;
3541 		}
3542 		count += rc;
3543 	}
3544 
3545 	return count;
3546 }
3547 
3548 static int
3549 spdk_nvmf_rdma_trid_from_cm_id(struct rdma_cm_id *id,
3550 			       struct spdk_nvme_transport_id *trid,
3551 			       bool peer)
3552 {
3553 	struct sockaddr *saddr;
3554 	uint16_t port;
3555 
3556 	trid->trtype = SPDK_NVME_TRANSPORT_RDMA;
3557 
3558 	if (peer) {
3559 		saddr = rdma_get_peer_addr(id);
3560 	} else {
3561 		saddr = rdma_get_local_addr(id);
3562 	}
3563 	switch (saddr->sa_family) {
3564 	case AF_INET: {
3565 		struct sockaddr_in *saddr_in = (struct sockaddr_in *)saddr;
3566 
3567 		trid->adrfam = SPDK_NVMF_ADRFAM_IPV4;
3568 		inet_ntop(AF_INET, &saddr_in->sin_addr,
3569 			  trid->traddr, sizeof(trid->traddr));
3570 		if (peer) {
3571 			port = ntohs(rdma_get_dst_port(id));
3572 		} else {
3573 			port = ntohs(rdma_get_src_port(id));
3574 		}
3575 		snprintf(trid->trsvcid, sizeof(trid->trsvcid), "%u", port);
3576 		break;
3577 	}
3578 	case AF_INET6: {
3579 		struct sockaddr_in6 *saddr_in = (struct sockaddr_in6 *)saddr;
3580 		trid->adrfam = SPDK_NVMF_ADRFAM_IPV6;
3581 		inet_ntop(AF_INET6, &saddr_in->sin6_addr,
3582 			  trid->traddr, sizeof(trid->traddr));
3583 		if (peer) {
3584 			port = ntohs(rdma_get_dst_port(id));
3585 		} else {
3586 			port = ntohs(rdma_get_src_port(id));
3587 		}
3588 		snprintf(trid->trsvcid, sizeof(trid->trsvcid), "%u", port);
3589 		break;
3590 	}
3591 	default:
3592 		return -1;
3593 
3594 	}
3595 
3596 	return 0;
3597 }
3598 
3599 static int
3600 spdk_nvmf_rdma_qpair_get_peer_trid(struct spdk_nvmf_qpair *qpair,
3601 				   struct spdk_nvme_transport_id *trid)
3602 {
3603 	struct spdk_nvmf_rdma_qpair	*rqpair;
3604 
3605 	rqpair = SPDK_CONTAINEROF(qpair, struct spdk_nvmf_rdma_qpair, qpair);
3606 
3607 	return spdk_nvmf_rdma_trid_from_cm_id(rqpair->cm_id, trid, true);
3608 }
3609 
3610 static int
3611 spdk_nvmf_rdma_qpair_get_local_trid(struct spdk_nvmf_qpair *qpair,
3612 				    struct spdk_nvme_transport_id *trid)
3613 {
3614 	struct spdk_nvmf_rdma_qpair	*rqpair;
3615 
3616 	rqpair = SPDK_CONTAINEROF(qpair, struct spdk_nvmf_rdma_qpair, qpair);
3617 
3618 	return spdk_nvmf_rdma_trid_from_cm_id(rqpair->cm_id, trid, false);
3619 }
3620 
3621 static int
3622 spdk_nvmf_rdma_qpair_get_listen_trid(struct spdk_nvmf_qpair *qpair,
3623 				     struct spdk_nvme_transport_id *trid)
3624 {
3625 	struct spdk_nvmf_rdma_qpair	*rqpair;
3626 
3627 	rqpair = SPDK_CONTAINEROF(qpair, struct spdk_nvmf_rdma_qpair, qpair);
3628 
3629 	return spdk_nvmf_rdma_trid_from_cm_id(rqpair->listen_id, trid, false);
3630 }
3631 
3632 void
3633 spdk_nvmf_rdma_init_hooks(struct spdk_nvme_rdma_hooks *hooks)
3634 {
3635 	g_nvmf_hooks = *hooks;
3636 }
3637 
3638 const struct spdk_nvmf_transport_ops spdk_nvmf_transport_rdma = {
3639 	.type = SPDK_NVME_TRANSPORT_RDMA,
3640 	.opts_init = spdk_nvmf_rdma_opts_init,
3641 	.create = spdk_nvmf_rdma_create,
3642 	.destroy = spdk_nvmf_rdma_destroy,
3643 
3644 	.listen = spdk_nvmf_rdma_listen,
3645 	.stop_listen = spdk_nvmf_rdma_stop_listen,
3646 	.accept = spdk_nvmf_rdma_accept,
3647 
3648 	.listener_discover = spdk_nvmf_rdma_discover,
3649 
3650 	.poll_group_create = spdk_nvmf_rdma_poll_group_create,
3651 	.poll_group_destroy = spdk_nvmf_rdma_poll_group_destroy,
3652 	.poll_group_add = spdk_nvmf_rdma_poll_group_add,
3653 	.poll_group_poll = spdk_nvmf_rdma_poll_group_poll,
3654 
3655 	.req_free = spdk_nvmf_rdma_request_free,
3656 	.req_complete = spdk_nvmf_rdma_request_complete,
3657 
3658 	.qpair_fini = spdk_nvmf_rdma_close_qpair,
3659 	.qpair_get_peer_trid = spdk_nvmf_rdma_qpair_get_peer_trid,
3660 	.qpair_get_local_trid = spdk_nvmf_rdma_qpair_get_local_trid,
3661 	.qpair_get_listen_trid = spdk_nvmf_rdma_qpair_get_listen_trid,
3662 
3663 };
3664 
3665 SPDK_LOG_REGISTER_COMPONENT("rdma", SPDK_LOG_RDMA)
3666