xref: /spdk/lib/nvmf/rdma.c (revision edbca2a67610cf6ebb9755c839e307d1d18375da)
1 /*-
2  *   BSD LICENSE
3  *
4  *   Copyright (c) Intel Corporation.
5  *   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 <arpa/inet.h>
35 #include <fcntl.h>
36 #include <errno.h>
37 #include <infiniband/verbs.h>
38 #include <rdma/rdma_cma.h>
39 #include <rdma/rdma_verbs.h>
40 #include <unistd.h>
41 #include <stdio.h>
42 #include <stdint.h>
43 
44 #include "nvmf_internal.h"
45 #include "request.h"
46 #include "session.h"
47 #include "subsystem.h"
48 #include "transport.h"
49 
50 #include "spdk/assert.h"
51 #include "spdk/nvmf.h"
52 #include "spdk/nvmf_spec.h"
53 #include "spdk/string.h"
54 #include "spdk/trace.h"
55 #include "spdk/util.h"
56 
57 #include "spdk_internal/log.h"
58 
59 /*
60  RDMA Connection Resouce Defaults
61  */
62 #define NVMF_DEFAULT_TX_SGE		1
63 #define NVMF_DEFAULT_RX_SGE		2
64 
65 struct spdk_nvmf_rdma_buf {
66 	SLIST_ENTRY(spdk_nvmf_rdma_buf) link;
67 };
68 
69 /* This structure holds commands as they are received off the wire.
70  * It must be dynamically paired with a full request object
71  * (spdk_nvmf_rdma_request) to service a request. It is separate
72  * from the request because RDMA does not appear to order
73  * completions, so occasionally we'll get a new incoming
74  * command when there aren't any free request objects.
75  */
76 struct spdk_nvmf_rdma_recv {
77 	struct ibv_recv_wr		wr;
78 	struct ibv_sge			sgl[NVMF_DEFAULT_RX_SGE];
79 
80 	/* In-capsule data buffer */
81 	uint8_t				*buf;
82 
83 	TAILQ_ENTRY(spdk_nvmf_rdma_recv) link;
84 
85 #ifdef DEBUG
86 	bool				in_use;
87 #endif
88 };
89 
90 struct spdk_nvmf_rdma_request {
91 	struct spdk_nvmf_request		req;
92 	bool					data_from_pool;
93 
94 	struct spdk_nvmf_rdma_recv		*recv;
95 
96 	struct {
97 		struct	ibv_send_wr		wr;
98 		struct	ibv_sge			sgl[NVMF_DEFAULT_TX_SGE];
99 	} rsp;
100 
101 	struct {
102 		struct ibv_send_wr		wr;
103 		struct ibv_sge			sgl[NVMF_DEFAULT_TX_SGE];
104 	} data;
105 
106 	TAILQ_ENTRY(spdk_nvmf_rdma_request)	link;
107 };
108 
109 struct spdk_nvmf_rdma_conn {
110 	struct spdk_nvmf_conn			conn;
111 
112 	struct rdma_cm_id			*cm_id;
113 	struct ibv_cq				*cq;
114 
115 	/* The maximum number of I/O outstanding on this connection at one time */
116 	uint16_t				max_queue_depth;
117 
118 	/* The maximum number of active RDMA READ and WRITE operations at one time */
119 	uint16_t				max_rw_depth;
120 
121 	/* The current number of I/O outstanding on this connection. This number
122 	 * includes all I/O from the time the capsule is first received until it is
123 	 * completed.
124 	 */
125 	uint16_t				cur_queue_depth;
126 
127 	/* The number of RDMA READ and WRITE requests that are outstanding */
128 	uint16_t				cur_rdma_rw_depth;
129 
130 	/* Receives that are waiting for a request object */
131 	TAILQ_HEAD(, spdk_nvmf_rdma_recv)	incoming_queue;
132 
133 	/* Requests that are not in use */
134 	TAILQ_HEAD(, spdk_nvmf_rdma_request)	free_queue;
135 
136 	/* Requests that are waiting to obtain a data buffer */
137 	TAILQ_HEAD(, spdk_nvmf_rdma_request)	pending_data_buf_queue;
138 
139 	/* Requests that are waiting to perform an RDMA READ or WRITE */
140 	TAILQ_HEAD(, spdk_nvmf_rdma_request)	pending_rdma_rw_queue;
141 
142 	/* Array of size "max_queue_depth" containing RDMA requests. */
143 	struct spdk_nvmf_rdma_request		*reqs;
144 
145 	/* Array of size "max_queue_depth" containing RDMA recvs. */
146 	struct spdk_nvmf_rdma_recv		*recvs;
147 
148 	/* Array of size "max_queue_depth" containing 64 byte capsules
149 	 * used for receive.
150 	 */
151 	union nvmf_h2c_msg			*cmds;
152 	struct ibv_mr				*cmds_mr;
153 
154 	/* Array of size "max_queue_depth" containing 16 byte completions
155 	 * to be sent back to the user.
156 	 */
157 	union nvmf_c2h_msg			*cpls;
158 	struct ibv_mr				*cpls_mr;
159 
160 	/* Array of size "max_queue_depth * InCapsuleDataSize" containing
161 	 * buffers to be used for in capsule data.
162 	 */
163 	void					*bufs;
164 	struct ibv_mr				*bufs_mr;
165 
166 	TAILQ_ENTRY(spdk_nvmf_rdma_conn)	link;
167 };
168 
169 /* List of RDMA connections that have not yet received a CONNECT capsule */
170 static TAILQ_HEAD(, spdk_nvmf_rdma_conn) g_pending_conns = TAILQ_HEAD_INITIALIZER(g_pending_conns);
171 
172 struct spdk_nvmf_rdma_session {
173 	struct spdk_nvmf_session		session;
174 
175 	SLIST_HEAD(, spdk_nvmf_rdma_buf)	data_buf_pool;
176 
177 	struct ibv_context			*verbs;
178 
179 	uint8_t					*buf;
180 	struct ibv_mr				*buf_mr;
181 };
182 
183 struct spdk_nvmf_rdma_listen_addr {
184 	char					*traddr;
185 	char					*trsvcid;
186 	struct rdma_cm_id			*id;
187 	struct ibv_device_attr 			attr;
188 	struct ibv_comp_channel			*comp_channel;
189 	uint32_t				ref;
190 	bool					is_listened;
191 	TAILQ_ENTRY(spdk_nvmf_rdma_listen_addr)	link;
192 };
193 
194 struct spdk_nvmf_rdma {
195 	struct rdma_event_channel	*event_channel;
196 
197 	pthread_mutex_t 		lock;
198 
199 	uint16_t 			max_queue_depth;
200 	uint32_t 			max_io_size;
201 	uint32_t 			in_capsule_data_size;
202 
203 	TAILQ_HEAD(, spdk_nvmf_rdma_listen_addr)	listen_addrs;
204 };
205 
206 static struct spdk_nvmf_rdma g_rdma = {
207 	.lock = PTHREAD_MUTEX_INITIALIZER,
208 	.listen_addrs = TAILQ_HEAD_INITIALIZER(g_rdma.listen_addrs),
209 };
210 
211 static inline struct spdk_nvmf_rdma_conn *
212 get_rdma_conn(struct spdk_nvmf_conn *conn)
213 {
214 	return (struct spdk_nvmf_rdma_conn *)((uintptr_t)conn - offsetof(struct spdk_nvmf_rdma_conn, conn));
215 }
216 
217 static inline struct spdk_nvmf_rdma_request *
218 get_rdma_req(struct spdk_nvmf_request *req)
219 {
220 	return (struct spdk_nvmf_rdma_request *)((uintptr_t)req - offsetof(struct spdk_nvmf_rdma_request,
221 			req));
222 }
223 
224 static inline struct spdk_nvmf_rdma_session *
225 get_rdma_sess(struct spdk_nvmf_session *sess)
226 {
227 	return (struct spdk_nvmf_rdma_session *)((uintptr_t)sess - offsetof(struct spdk_nvmf_rdma_session,
228 			session));
229 }
230 
231 static void
232 spdk_nvmf_rdma_conn_destroy(struct spdk_nvmf_rdma_conn *rdma_conn)
233 {
234 	if (rdma_conn->cmds_mr) {
235 		ibv_dereg_mr(rdma_conn->cmds_mr);
236 	}
237 
238 	if (rdma_conn->cpls_mr) {
239 		ibv_dereg_mr(rdma_conn->cpls_mr);
240 	}
241 
242 	if (rdma_conn->bufs_mr) {
243 		ibv_dereg_mr(rdma_conn->bufs_mr);
244 	}
245 
246 	if (rdma_conn->cm_id) {
247 		rdma_destroy_qp(rdma_conn->cm_id);
248 		rdma_destroy_id(rdma_conn->cm_id);
249 	}
250 
251 	if (rdma_conn->cq) {
252 		ibv_destroy_cq(rdma_conn->cq);
253 	}
254 
255 	/* Free all memory */
256 	spdk_free(rdma_conn->cmds);
257 	spdk_free(rdma_conn->cpls);
258 	spdk_free(rdma_conn->bufs);
259 	free(rdma_conn->reqs);
260 	free(rdma_conn);
261 }
262 
263 static struct spdk_nvmf_rdma_conn *
264 spdk_nvmf_rdma_conn_create(struct rdma_cm_id *id, struct ibv_comp_channel *channel,
265 			   uint16_t max_queue_depth, uint16_t max_rw_depth, uint32_t subsystem_id)
266 {
267 	struct spdk_nvmf_rdma_conn	*rdma_conn;
268 	struct spdk_nvmf_conn		*conn;
269 	int				rc, i;
270 	struct ibv_qp_init_attr		attr;
271 	struct spdk_nvmf_rdma_recv	*rdma_recv;
272 	struct spdk_nvmf_rdma_request	*rdma_req;
273 
274 	rdma_conn = calloc(1, sizeof(struct spdk_nvmf_rdma_conn));
275 	if (rdma_conn == NULL) {
276 		SPDK_ERRLOG("Could not allocate new connection.\n");
277 		return NULL;
278 	}
279 
280 	rdma_conn->max_queue_depth = max_queue_depth;
281 	rdma_conn->max_rw_depth = max_rw_depth;
282 	TAILQ_INIT(&rdma_conn->incoming_queue);
283 	TAILQ_INIT(&rdma_conn->free_queue);
284 	TAILQ_INIT(&rdma_conn->pending_data_buf_queue);
285 	TAILQ_INIT(&rdma_conn->pending_rdma_rw_queue);
286 
287 	rdma_conn->cq = ibv_create_cq(id->verbs, max_queue_depth * 3, rdma_conn, channel, 0);
288 	if (!rdma_conn->cq) {
289 		SPDK_ERRLOG("Unable to create completion queue\n");
290 		SPDK_ERRLOG("Completion Channel: %p Id: %p Verbs: %p\n", channel, id, id->verbs);
291 		SPDK_ERRLOG("Errno %d: %s\n", errno, strerror(errno));
292 		rdma_destroy_id(id);
293 		spdk_nvmf_rdma_conn_destroy(rdma_conn);
294 		return NULL;
295 	}
296 
297 	memset(&attr, 0, sizeof(struct ibv_qp_init_attr));
298 	attr.qp_type		= IBV_QPT_RC;
299 	attr.send_cq		= rdma_conn->cq;
300 	attr.recv_cq		= rdma_conn->cq;
301 	attr.cap.max_send_wr	= max_queue_depth * 2; /* SEND, READ, and WRITE operations */
302 	attr.cap.max_recv_wr	= max_queue_depth; /* RECV operations */
303 	attr.cap.max_send_sge	= NVMF_DEFAULT_TX_SGE;
304 	attr.cap.max_recv_sge	= NVMF_DEFAULT_RX_SGE;
305 
306 	rc = rdma_create_qp(id, NULL, &attr);
307 	if (rc) {
308 		SPDK_ERRLOG("rdma_create_qp failed\n");
309 		SPDK_ERRLOG("Errno %d: %s\n", errno, strerror(errno));
310 		rdma_destroy_id(id);
311 		spdk_nvmf_rdma_conn_destroy(rdma_conn);
312 		return NULL;
313 	}
314 
315 	conn = &rdma_conn->conn;
316 	conn->transport = &spdk_nvmf_transport_rdma;
317 	id->context = conn;
318 	rdma_conn->cm_id = id;
319 
320 	SPDK_TRACELOG(SPDK_TRACE_RDMA, "New RDMA Connection: %p\n", conn);
321 
322 	rdma_conn->reqs = calloc(max_queue_depth, sizeof(*rdma_conn->reqs));
323 	rdma_conn->recvs = calloc(max_queue_depth, sizeof(*rdma_conn->recvs));
324 	rdma_conn->cmds = spdk_zmalloc(max_queue_depth * sizeof(*rdma_conn->cmds),
325 				       0x1000, NULL);
326 	rdma_conn->cpls = spdk_zmalloc(max_queue_depth * sizeof(*rdma_conn->cpls),
327 				       0x1000, NULL);
328 	rdma_conn->bufs = spdk_zmalloc(max_queue_depth * g_rdma.in_capsule_data_size,
329 				       0x1000, NULL);
330 	if (!rdma_conn->reqs || !rdma_conn->recvs || !rdma_conn->cmds ||
331 	    !rdma_conn->cpls || !rdma_conn->bufs) {
332 		SPDK_ERRLOG("Unable to allocate sufficient memory for RDMA queue.\n");
333 		spdk_nvmf_rdma_conn_destroy(rdma_conn);
334 		return NULL;
335 	}
336 
337 	rdma_conn->cmds_mr = ibv_reg_mr(id->pd, rdma_conn->cmds,
338 					max_queue_depth * sizeof(*rdma_conn->cmds),
339 					IBV_ACCESS_LOCAL_WRITE);
340 	rdma_conn->cpls_mr = ibv_reg_mr(id->pd, rdma_conn->cpls,
341 					max_queue_depth * sizeof(*rdma_conn->cpls),
342 					0);
343 	rdma_conn->bufs_mr = ibv_reg_mr(id->pd, rdma_conn->bufs,
344 					max_queue_depth * g_rdma.in_capsule_data_size,
345 					IBV_ACCESS_LOCAL_WRITE |
346 					IBV_ACCESS_REMOTE_WRITE);
347 	if (!rdma_conn->cmds_mr || !rdma_conn->cpls_mr || !rdma_conn->bufs_mr) {
348 		SPDK_ERRLOG("Unable to register required memory for RDMA queue.\n");
349 		spdk_nvmf_rdma_conn_destroy(rdma_conn);
350 		return NULL;
351 	}
352 	SPDK_TRACELOG(SPDK_TRACE_RDMA, "Command Array: %p Length: %lx LKey: %x\n",
353 		      rdma_conn->cmds, max_queue_depth * sizeof(*rdma_conn->cmds), rdma_conn->cmds_mr->lkey);
354 	SPDK_TRACELOG(SPDK_TRACE_RDMA, "Completion Array: %p Length: %lx LKey: %x\n",
355 		      rdma_conn->cpls, max_queue_depth * sizeof(*rdma_conn->cpls), rdma_conn->cpls_mr->lkey);
356 	SPDK_TRACELOG(SPDK_TRACE_RDMA, "In Capsule Data Array: %p Length: %x LKey: %x\n",
357 		      rdma_conn->bufs, max_queue_depth * g_rdma.in_capsule_data_size, rdma_conn->bufs_mr->lkey);
358 
359 	for (i = 0; i < max_queue_depth; i++) {
360 		struct ibv_recv_wr *bad_wr = NULL;
361 
362 		rdma_recv = &rdma_conn->recvs[i];
363 
364 		/* Set up memory to receive commands */
365 		rdma_recv->buf = (void *)((uintptr_t)rdma_conn->bufs + (i * g_rdma.in_capsule_data_size));
366 
367 		rdma_recv->sgl[0].addr = (uintptr_t)&rdma_conn->cmds[i];
368 		rdma_recv->sgl[0].length = sizeof(rdma_conn->cmds[i]);
369 		rdma_recv->sgl[0].lkey = rdma_conn->cmds_mr->lkey;
370 
371 		rdma_recv->sgl[1].addr = (uintptr_t)rdma_recv->buf;
372 		rdma_recv->sgl[1].length = g_rdma.in_capsule_data_size;
373 		rdma_recv->sgl[1].lkey = rdma_conn->bufs_mr->lkey;
374 
375 		rdma_recv->wr.wr_id = (uintptr_t)rdma_recv;
376 		rdma_recv->wr.sg_list = rdma_recv->sgl;
377 		rdma_recv->wr.num_sge = SPDK_COUNTOF(rdma_recv->sgl);
378 #ifdef DEBUG
379 		rdma_recv->in_use = false;
380 #endif
381 
382 		rc = ibv_post_recv(rdma_conn->cm_id->qp, &rdma_recv->wr, &bad_wr);
383 		if (rc) {
384 			SPDK_ERRLOG("Unable to post capsule for RDMA RECV\n");
385 			spdk_nvmf_rdma_conn_destroy(rdma_conn);
386 			return NULL;
387 		}
388 	}
389 
390 	for (i = 0; i < max_queue_depth; i++) {
391 		rdma_req = &rdma_conn->reqs[i];
392 
393 		rdma_req->req.conn = &rdma_conn->conn;
394 		rdma_req->req.cmd = NULL;
395 
396 		/* Set up memory to send responses */
397 		rdma_req->req.rsp = &rdma_conn->cpls[i];
398 
399 		rdma_req->rsp.sgl[0].addr = (uintptr_t)&rdma_conn->cpls[i];
400 		rdma_req->rsp.sgl[0].length = sizeof(rdma_conn->cpls[i]);
401 		rdma_req->rsp.sgl[0].lkey = rdma_conn->cpls_mr->lkey;
402 
403 		rdma_req->rsp.wr.wr_id = (uintptr_t)rdma_req;
404 		rdma_req->rsp.wr.next = NULL;
405 		rdma_req->rsp.wr.opcode = IBV_WR_SEND;
406 		rdma_req->rsp.wr.send_flags = IBV_SEND_SIGNALED;
407 		rdma_req->rsp.wr.sg_list = rdma_req->rsp.sgl;
408 		rdma_req->rsp.wr.num_sge = SPDK_COUNTOF(rdma_req->rsp.sgl);
409 
410 		/* Set up memory for data buffers */
411 		rdma_req->data.wr.wr_id = (uint64_t)rdma_req;
412 		rdma_req->data.wr.next = NULL;
413 		rdma_req->data.wr.send_flags = IBV_SEND_SIGNALED;
414 		rdma_req->data.wr.sg_list = rdma_req->data.sgl;
415 		rdma_req->data.wr.num_sge = SPDK_COUNTOF(rdma_req->data.sgl);
416 
417 		TAILQ_INSERT_TAIL(&rdma_conn->free_queue, rdma_req, link);
418 	}
419 
420 	return rdma_conn;
421 }
422 
423 static int
424 request_transfer_in(struct spdk_nvmf_request *req)
425 {
426 	int				rc;
427 	struct spdk_nvmf_rdma_request	*rdma_req = get_rdma_req(req);
428 	struct spdk_nvmf_conn 		*conn = req->conn;
429 	struct spdk_nvmf_rdma_conn 	*rdma_conn = get_rdma_conn(conn);
430 	struct ibv_send_wr		*bad_wr = NULL;
431 
432 	assert(req->xfer == SPDK_NVME_DATA_HOST_TO_CONTROLLER);
433 
434 	rdma_conn->cur_rdma_rw_depth++;
435 
436 	SPDK_TRACELOG(SPDK_TRACE_RDMA, "RDMA READ POSTED. Request: %p Connection: %p\n", req, conn);
437 	spdk_trace_record(TRACE_RDMA_READ_START, 0, 0, (uintptr_t)req, 0);
438 
439 	rdma_req->data.wr.opcode = IBV_WR_RDMA_READ;
440 	rdma_req->data.wr.next = NULL;
441 	rc = ibv_post_send(rdma_conn->cm_id->qp, &rdma_req->data.wr, &bad_wr);
442 	if (rc) {
443 		SPDK_ERRLOG("Unable to transfer data from host to target\n");
444 		return -1;
445 	}
446 
447 	return 0;
448 }
449 
450 static int
451 request_transfer_out(struct spdk_nvmf_request *req)
452 {
453 	int 				rc;
454 	struct spdk_nvmf_rdma_request	*rdma_req = get_rdma_req(req);
455 	struct spdk_nvmf_conn		*conn = req->conn;
456 	struct spdk_nvmf_rdma_conn 	*rdma_conn = get_rdma_conn(conn);
457 	struct spdk_nvme_cpl		*rsp = &req->rsp->nvme_cpl;
458 	struct ibv_recv_wr		*bad_recv_wr = NULL;
459 	struct ibv_send_wr		*send_wr, *bad_send_wr = NULL;
460 
461 	/* Advance our sq_head pointer */
462 	if (conn->sq_head == conn->sq_head_max) {
463 		conn->sq_head = 0;
464 	} else {
465 		conn->sq_head++;
466 	}
467 	rsp->sqhd = conn->sq_head;
468 
469 	/* Post the capsule to the recv buffer */
470 	assert(rdma_req->recv != NULL);
471 #ifdef DEBUG
472 	assert(rdma_req->recv->in_use == true);
473 	rdma_req->recv->in_use = false;
474 #endif
475 	SPDK_TRACELOG(SPDK_TRACE_RDMA, "RDMA RECV POSTED. Recv: %p Connection: %p\n", rdma_req->recv,
476 		      rdma_conn);
477 	rc = ibv_post_recv(rdma_conn->cm_id->qp, &rdma_req->recv->wr, &bad_recv_wr);
478 	if (rc) {
479 		SPDK_ERRLOG("Unable to re-post rx descriptor\n");
480 		return rc;
481 	}
482 	rdma_req->recv = NULL;
483 
484 	/* Build the response which consists of an optional
485 	 * RDMA WRITE to transfer data, plus an RDMA SEND
486 	 * containing the response.
487 	 */
488 	send_wr = &rdma_req->rsp.wr;
489 
490 	if (rsp->status.sc == SPDK_NVME_SC_SUCCESS &&
491 	    req->xfer == SPDK_NVME_DATA_CONTROLLER_TO_HOST) {
492 		SPDK_TRACELOG(SPDK_TRACE_RDMA, "RDMA WRITE POSTED. Request: %p Connection: %p\n", req, conn);
493 		spdk_trace_record(TRACE_RDMA_WRITE_START, 0, 0, (uintptr_t)req, 0);
494 
495 		rdma_conn->cur_rdma_rw_depth++;
496 		rdma_req->data.wr.opcode = IBV_WR_RDMA_WRITE;
497 
498 		rdma_req->data.wr.next = send_wr;
499 		send_wr = &rdma_req->data.wr;
500 	}
501 
502 	SPDK_TRACELOG(SPDK_TRACE_RDMA, "RDMA SEND POSTED. Request: %p Connection: %p\n", req, conn);
503 	spdk_trace_record(TRACE_NVMF_IO_COMPLETE, 0, 0, (uintptr_t)req, 0);
504 
505 	/* Send the completion */
506 	rc = ibv_post_send(rdma_conn->cm_id->qp, send_wr, &bad_send_wr);
507 	if (rc) {
508 		SPDK_ERRLOG("Unable to send response capsule\n");
509 	}
510 
511 	return rc;
512 }
513 
514 static int
515 spdk_nvmf_rdma_request_transfer_data(struct spdk_nvmf_request *req)
516 {
517 	struct spdk_nvmf_rdma_request *rdma_req = get_rdma_req(req);
518 	struct spdk_nvmf_conn *conn = req->conn;
519 	struct spdk_nvmf_rdma_conn *rdma_conn = get_rdma_conn(conn);
520 
521 	if (req->xfer == SPDK_NVME_DATA_NONE) {
522 		/* If no data transfer, this can bypass the queue */
523 		return request_transfer_out(req);
524 	}
525 
526 	if (rdma_conn->cur_rdma_rw_depth < rdma_conn->max_rw_depth) {
527 		if (req->xfer == SPDK_NVME_DATA_CONTROLLER_TO_HOST) {
528 			return request_transfer_out(req);
529 		} else if (req->xfer == SPDK_NVME_DATA_HOST_TO_CONTROLLER) {
530 			return request_transfer_in(req);
531 		}
532 	} else {
533 		TAILQ_INSERT_TAIL(&rdma_conn->pending_rdma_rw_queue, rdma_req, link);
534 	}
535 
536 	return 0;
537 }
538 
539 static int
540 nvmf_rdma_connect(struct rdma_cm_event *event)
541 {
542 	struct spdk_nvmf_rdma_conn	*rdma_conn = NULL;
543 	struct spdk_nvmf_rdma_listen_addr *addr;
544 	struct rdma_conn_param		*rdma_param = NULL;
545 	struct rdma_conn_param		ctrlr_event_data;
546 	const struct spdk_nvmf_rdma_request_private_data *private_data = NULL;
547 	struct spdk_nvmf_rdma_accept_private_data accept_data;
548 	uint16_t			sts = 0;
549 	uint16_t			max_queue_depth;
550 	uint16_t			max_rw_depth;
551 	uint32_t			subsystem_id = 0;
552 	int 				rc;
553 
554 	if (event->id == NULL) {
555 		SPDK_ERRLOG("connect request: missing cm_id\n");
556 		goto err0;
557 	}
558 
559 	if (event->id->verbs == NULL) {
560 		SPDK_ERRLOG("connect request: missing cm_id ibv_context\n");
561 		goto err0;
562 	}
563 
564 	rdma_param = &event->param.conn;
565 	if (rdma_param->private_data == NULL ||
566 	    rdma_param->private_data_len < sizeof(struct spdk_nvmf_rdma_request_private_data)) {
567 		SPDK_ERRLOG("connect request: no private data provided\n");
568 		goto err0;
569 	}
570 	private_data = rdma_param->private_data;
571 
572 	SPDK_TRACELOG(SPDK_TRACE_RDMA, "Connect Recv on fabric intf name %s, dev_name %s\n",
573 		      event->id->verbs->device->name, event->id->verbs->device->dev_name);
574 
575 	addr = event->listen_id->context;
576 	SPDK_TRACELOG(SPDK_TRACE_RDMA, "Listen Id was %p with verbs %p. ListenAddr: %p\n",
577 		      event->listen_id, event->listen_id->verbs, addr);
578 
579 	/* Figure out the supported queue depth. This is a multi-step process
580 	 * that takes into account hardware maximums, host provided values,
581 	 * and our target's internal memory limits */
582 
583 	SPDK_TRACELOG(SPDK_TRACE_RDMA, "Calculating Queue Depth\n");
584 
585 	/* Start with the maximum queue depth allowed by the target */
586 	max_queue_depth = g_rdma.max_queue_depth;
587 	max_rw_depth = g_rdma.max_queue_depth;
588 	SPDK_TRACELOG(SPDK_TRACE_RDMA, "Target Max Queue Depth: %d\n", g_rdma.max_queue_depth);
589 
590 	/* Next check the local NIC's hardware limitations */
591 	SPDK_TRACELOG(SPDK_TRACE_RDMA,
592 		      "Local NIC Max Send/Recv Queue Depth: %d Max Read/Write Queue Depth: %d\n",
593 		      addr->attr.max_qp_wr, addr->attr.max_qp_rd_atom);
594 	max_queue_depth = spdk_min(max_queue_depth, addr->attr.max_qp_wr);
595 	max_rw_depth = spdk_min(max_rw_depth, addr->attr.max_qp_rd_atom);
596 
597 	/* Next check the remote NIC's hardware limitations */
598 	SPDK_TRACELOG(SPDK_TRACE_RDMA,
599 		      "Host (Initiator) NIC Max Incoming RDMA R/W operations: %d Max Outgoing RDMA R/W operations: %d\n",
600 		      rdma_param->initiator_depth, rdma_param->responder_resources);
601 	if (rdma_param->initiator_depth > 0) {
602 		max_rw_depth = spdk_min(max_rw_depth, rdma_param->initiator_depth);
603 	}
604 
605 	/* Finally check for the host software requested values, which are
606 	 * optional. */
607 	if (rdma_param->private_data != NULL &&
608 	    rdma_param->private_data_len >= sizeof(struct spdk_nvmf_rdma_request_private_data)) {
609 		SPDK_TRACELOG(SPDK_TRACE_RDMA, "Host Receive Queue Size: %d\n", private_data->hrqsize);
610 		SPDK_TRACELOG(SPDK_TRACE_RDMA, "Host Send Queue Size: %d\n", private_data->hsqsize);
611 		max_queue_depth = spdk_min(max_queue_depth, private_data->hrqsize);
612 		max_queue_depth = spdk_min(max_queue_depth, private_data->hsqsize + 1);
613 	}
614 
615 	SPDK_TRACELOG(SPDK_TRACE_RDMA, "Final Negotiated Queue Depth: %d R/W Depth: %d\n",
616 		      max_queue_depth, max_rw_depth);
617 
618 	/* Init the NVMf rdma transport connection */
619 	rdma_conn = spdk_nvmf_rdma_conn_create(event->id, addr->comp_channel, max_queue_depth,
620 					       max_rw_depth, subsystem_id);
621 	if (rdma_conn == NULL) {
622 		SPDK_ERRLOG("Error on nvmf connection creation\n");
623 		goto err1;
624 	}
625 
626 	accept_data.recfmt = 0;
627 	accept_data.crqsize = max_queue_depth;
628 	ctrlr_event_data = *rdma_param;
629 	ctrlr_event_data.private_data = &accept_data;
630 	ctrlr_event_data.private_data_len = sizeof(accept_data);
631 	if (event->id->ps == RDMA_PS_TCP) {
632 		ctrlr_event_data.responder_resources = 0; /* We accept 0 reads from the host */
633 		ctrlr_event_data.initiator_depth = max_rw_depth;
634 	}
635 
636 	rc = rdma_accept(event->id, &ctrlr_event_data);
637 	if (rc) {
638 		SPDK_ERRLOG("Error on rdma_accept\n");
639 		goto err2;
640 	}
641 	SPDK_TRACELOG(SPDK_TRACE_RDMA, "Sent back the accept\n");
642 
643 	/* Add this RDMA connection to the global list until a CONNECT capsule
644 	 * is received. */
645 	TAILQ_INSERT_TAIL(&g_pending_conns, rdma_conn, link);
646 
647 	return 0;
648 
649 err2:
650 	spdk_nvmf_rdma_conn_destroy(rdma_conn);
651 
652 err1: {
653 		struct spdk_nvmf_rdma_reject_private_data rej_data;
654 
655 		rej_data.status.sc = sts;
656 		rdma_reject(event->id, &ctrlr_event_data, sizeof(rej_data));
657 	}
658 err0:
659 	return -1;
660 }
661 
662 static int
663 nvmf_rdma_disconnect(struct rdma_cm_event *evt)
664 {
665 	struct spdk_nvmf_conn		*conn;
666 	struct spdk_nvmf_session	*session;
667 	struct spdk_nvmf_subsystem	*subsystem;
668 	struct spdk_nvmf_rdma_conn 	*rdma_conn;
669 
670 	if (evt->id == NULL) {
671 		SPDK_ERRLOG("disconnect request: missing cm_id\n");
672 		return -1;
673 	}
674 
675 	conn = evt->id->context;
676 	if (conn == NULL) {
677 		SPDK_ERRLOG("disconnect request: no active connection\n");
678 		return -1;
679 	}
680 	/* ack the disconnect event before rdma_destroy_id */
681 	rdma_ack_cm_event(evt);
682 
683 	rdma_conn = get_rdma_conn(conn);
684 
685 	session = conn->sess;
686 	if (session == NULL) {
687 		/* No session has been established yet. That means the conn
688 		 * must be in the pending connections list. Remove it. */
689 		TAILQ_REMOVE(&g_pending_conns, rdma_conn, link);
690 		spdk_nvmf_rdma_conn_destroy(rdma_conn);
691 		return 0;
692 	}
693 
694 	subsystem = session->subsys;
695 
696 	subsystem->disconnect_cb(subsystem->cb_ctx, conn);
697 
698 	return 0;
699 }
700 
701 #ifdef DEBUG
702 static const char *CM_EVENT_STR[] = {
703 	"RDMA_CM_EVENT_ADDR_RESOLVED",
704 	"RDMA_CM_EVENT_ADDR_ERROR",
705 	"RDMA_CM_EVENT_ROUTE_RESOLVED",
706 	"RDMA_CM_EVENT_ROUTE_ERROR",
707 	"RDMA_CM_EVENT_CONNECT_REQUEST",
708 	"RDMA_CM_EVENT_CONNECT_RESPONSE",
709 	"RDMA_CM_EVENT_CONNECT_ERROR",
710 	"RDMA_CM_EVENT_UNREACHABLE",
711 	"RDMA_CM_EVENT_REJECTED",
712 	"RDMA_CM_EVENT_ESTABLISHED",
713 	"RDMA_CM_EVENT_DISCONNECTED",
714 	"RDMA_CM_EVENT_DEVICE_REMOVAL",
715 	"RDMA_CM_EVENT_MULTICAST_JOIN",
716 	"RDMA_CM_EVENT_MULTICAST_ERROR",
717 	"RDMA_CM_EVENT_ADDR_CHANGE",
718 	"RDMA_CM_EVENT_TIMEWAIT_EXIT"
719 };
720 #endif /* DEBUG */
721 
722 typedef enum _spdk_nvmf_request_prep_type {
723 	SPDK_NVMF_REQUEST_PREP_ERROR = -1,
724 	SPDK_NVMF_REQUEST_PREP_READY = 0,
725 	SPDK_NVMF_REQUEST_PREP_PENDING_BUFFER = 1,
726 	SPDK_NVMF_REQUEST_PREP_PENDING_DATA = 2,
727 } spdk_nvmf_request_prep_type;
728 
729 static spdk_nvmf_request_prep_type
730 spdk_nvmf_request_prep_data(struct spdk_nvmf_request *req)
731 {
732 	struct spdk_nvme_cmd		*cmd = &req->cmd->nvme_cmd;
733 	struct spdk_nvme_cpl		*rsp = &req->rsp->nvme_cpl;
734 	struct spdk_nvmf_rdma_request	*rdma_req = get_rdma_req(req);
735 	struct spdk_nvmf_rdma_session	*rdma_sess;
736 	struct spdk_nvme_sgl_descriptor *sgl;
737 
738 	req->length = 0;
739 	req->data = NULL;
740 
741 	if (cmd->opc == SPDK_NVME_OPC_FABRIC) {
742 		req->xfer = spdk_nvme_opc_get_data_transfer(req->cmd->nvmf_cmd.fctype);
743 	} else {
744 		req->xfer = spdk_nvme_opc_get_data_transfer(cmd->opc);
745 		if ((req->conn->type == CONN_TYPE_AQ) &&
746 		    ((cmd->opc == SPDK_NVME_OPC_GET_FEATURES) ||
747 		     (cmd->opc == SPDK_NVME_OPC_SET_FEATURES))) {
748 			switch (cmd->cdw10 & 0xff) {
749 			case SPDK_NVME_FEAT_LBA_RANGE_TYPE:
750 			case SPDK_NVME_FEAT_AUTONOMOUS_POWER_STATE_TRANSITION:
751 			case SPDK_NVME_FEAT_HOST_IDENTIFIER:
752 				break;
753 			default:
754 				req->xfer = SPDK_NVME_DATA_NONE;
755 				break;
756 			}
757 		}
758 	}
759 
760 	if (req->xfer == SPDK_NVME_DATA_NONE) {
761 		return SPDK_NVMF_REQUEST_PREP_READY;
762 	}
763 
764 	sgl = &cmd->dptr.sgl1;
765 
766 	if (sgl->generic.type == SPDK_NVME_SGL_TYPE_KEYED_DATA_BLOCK &&
767 	    (sgl->keyed.subtype == SPDK_NVME_SGL_SUBTYPE_ADDRESS ||
768 	     sgl->keyed.subtype == SPDK_NVME_SGL_SUBTYPE_INVALIDATE_KEY)) {
769 		if (sgl->keyed.length > g_rdma.max_io_size) {
770 			SPDK_ERRLOG("SGL length 0x%x exceeds max io size 0x%x\n",
771 				    sgl->keyed.length, g_rdma.max_io_size);
772 			rsp->status.sc = SPDK_NVME_SC_DATA_SGL_LENGTH_INVALID;
773 			return SPDK_NVMF_REQUEST_PREP_ERROR;
774 		}
775 
776 		if (sgl->keyed.length == 0) {
777 			req->xfer = SPDK_NVME_DATA_NONE;
778 			return SPDK_NVMF_REQUEST_PREP_READY;
779 		}
780 
781 		req->length = sgl->keyed.length;
782 		rdma_req->data.sgl[0].length = sgl->keyed.length;
783 		rdma_req->data.wr.wr.rdma.rkey = sgl->keyed.key;
784 		rdma_req->data.wr.wr.rdma.remote_addr = sgl->address;
785 
786 		rdma_sess = get_rdma_sess(req->conn->sess);
787 		if (!rdma_sess) {
788 			/* The only time a connection won't have a session
789 			 * is when this is the CONNECT request.
790 			 */
791 			assert(cmd->opc == SPDK_NVME_OPC_FABRIC);
792 			assert(req->xfer == SPDK_NVME_DATA_HOST_TO_CONTROLLER);
793 			assert(req->length <= g_rdma.in_capsule_data_size);
794 
795 			/* Use the in capsule data buffer, even though this isn't in capsule data. */
796 			SPDK_TRACELOG(SPDK_TRACE_RDMA, "Request using in capsule buffer for non-capsule data\n");
797 			req->data = rdma_req->recv->buf;
798 			rdma_req->data.sgl[0].lkey = get_rdma_conn(req->conn)->bufs_mr->lkey;
799 			rdma_req->data_from_pool = false;
800 		} else {
801 			req->data = SLIST_FIRST(&rdma_sess->data_buf_pool);
802 			rdma_req->data.sgl[0].lkey = rdma_sess->buf_mr->lkey;
803 			rdma_req->data_from_pool = true;
804 			if (!req->data) {
805 				/* No available buffers. Queue this request up. */
806 				SPDK_TRACELOG(SPDK_TRACE_RDMA, "No available large data buffers. Queueing request %p\n", req);
807 				/* This will get assigned when we actually obtain a buffer */
808 				rdma_req->data.sgl[0].addr = (uintptr_t)NULL;
809 				return SPDK_NVMF_REQUEST_PREP_PENDING_BUFFER;
810 			}
811 
812 			SPDK_TRACELOG(SPDK_TRACE_RDMA, "Request %p took buffer from central pool\n", req);
813 			SLIST_REMOVE_HEAD(&rdma_sess->data_buf_pool, link);
814 		}
815 
816 		rdma_req->data.sgl[0].addr = (uintptr_t)req->data;
817 
818 		if (req->xfer == SPDK_NVME_DATA_HOST_TO_CONTROLLER) {
819 			return SPDK_NVMF_REQUEST_PREP_PENDING_DATA;
820 		} else {
821 			return SPDK_NVMF_REQUEST_PREP_READY;
822 		}
823 	} else if (sgl->generic.type == SPDK_NVME_SGL_TYPE_DATA_BLOCK &&
824 		   sgl->unkeyed.subtype == SPDK_NVME_SGL_SUBTYPE_OFFSET) {
825 		uint64_t offset = sgl->address;
826 		uint32_t max_len = g_rdma.in_capsule_data_size;
827 
828 		SPDK_TRACELOG(SPDK_TRACE_NVMF, "In-capsule data: offset 0x%" PRIx64 ", length 0x%x\n",
829 			      offset, sgl->unkeyed.length);
830 
831 		if (offset > max_len) {
832 			SPDK_ERRLOG("In-capsule offset 0x%" PRIx64 " exceeds capsule length 0x%x\n",
833 				    offset, max_len);
834 			rsp->status.sc = SPDK_NVME_SC_INVALID_SGL_OFFSET;
835 			return SPDK_NVMF_REQUEST_PREP_ERROR;
836 		}
837 		max_len -= (uint32_t)offset;
838 
839 		if (sgl->unkeyed.length > max_len) {
840 			SPDK_ERRLOG("In-capsule data length 0x%x exceeds capsule length 0x%x\n",
841 				    sgl->unkeyed.length, max_len);
842 			rsp->status.sc = SPDK_NVME_SC_DATA_SGL_LENGTH_INVALID;
843 			return SPDK_NVMF_REQUEST_PREP_ERROR;
844 		}
845 
846 		if (sgl->unkeyed.length == 0) {
847 			req->xfer = SPDK_NVME_DATA_NONE;
848 			return SPDK_NVMF_REQUEST_PREP_READY;
849 		}
850 
851 		req->data = rdma_req->recv->buf + offset;
852 		rdma_req->data_from_pool = false;
853 		req->length = sgl->unkeyed.length;
854 		return SPDK_NVMF_REQUEST_PREP_READY;
855 	}
856 
857 	SPDK_ERRLOG("Invalid NVMf I/O Command SGL:  Type 0x%x, Subtype 0x%x\n",
858 		    sgl->generic.type, sgl->generic.subtype);
859 	rsp->status.sc = SPDK_NVME_SC_SGL_DESCRIPTOR_TYPE_INVALID;
860 	return SPDK_NVMF_REQUEST_PREP_ERROR;
861 }
862 
863 static int
864 spdk_nvmf_rdma_handle_pending_rdma_rw(struct spdk_nvmf_conn *conn)
865 {
866 	struct spdk_nvmf_rdma_conn	*rdma_conn = get_rdma_conn(conn);
867 	struct spdk_nvmf_rdma_session	*rdma_sess;
868 	struct spdk_nvmf_rdma_request	*rdma_req, *tmp;
869 	int rc;
870 	int count = 0;
871 
872 	/* First, try to assign free data buffers to requests that need one */
873 	if (conn->sess) {
874 		rdma_sess = get_rdma_sess(conn->sess);
875 		TAILQ_FOREACH_SAFE(rdma_req, &rdma_conn->pending_data_buf_queue, link, tmp) {
876 			assert(rdma_req->req.data == NULL);
877 			rdma_req->req.data = SLIST_FIRST(&rdma_sess->data_buf_pool);
878 			if (!rdma_req->req.data) {
879 				break;
880 			}
881 			SLIST_REMOVE_HEAD(&rdma_sess->data_buf_pool, link);
882 			rdma_req->data.sgl[0].addr = (uintptr_t)rdma_req->req.data;
883 			TAILQ_REMOVE(&rdma_conn->pending_data_buf_queue, rdma_req, link);
884 			if (rdma_req->req.xfer == SPDK_NVME_DATA_HOST_TO_CONTROLLER) {
885 				TAILQ_INSERT_TAIL(&rdma_conn->pending_rdma_rw_queue, rdma_req, link);
886 			} else {
887 				rc = spdk_nvmf_request_exec(&rdma_req->req);
888 				if (rc < 0) {
889 					return -1;
890 				}
891 				count++;
892 			}
893 		}
894 	}
895 
896 	/* Try to initiate RDMA Reads or Writes on requests that have data buffers */
897 	while (rdma_conn->cur_rdma_rw_depth < rdma_conn->max_rw_depth) {
898 		if (TAILQ_EMPTY(&rdma_conn->pending_rdma_rw_queue)) {
899 			break;
900 		}
901 
902 		rdma_req = TAILQ_FIRST(&rdma_conn->pending_rdma_rw_queue);
903 		TAILQ_REMOVE(&rdma_conn->pending_rdma_rw_queue, rdma_req, link);
904 
905 		SPDK_TRACELOG(SPDK_TRACE_RDMA, "Submitting previously queued for RDMA R/W request %p\n", rdma_req);
906 
907 		rc = spdk_nvmf_rdma_request_transfer_data(&rdma_req->req);
908 		if (rc) {
909 			return -1;
910 		}
911 	}
912 
913 	return count;
914 }
915 
916 /* Public API callbacks begin here */
917 
918 static int
919 spdk_nvmf_rdma_init(uint16_t max_queue_depth, uint32_t max_io_size,
920 		    uint32_t in_capsule_data_size)
921 {
922 	int rc;
923 
924 	SPDK_NOTICELOG("*** RDMA Transport Init ***\n");
925 
926 	pthread_mutex_lock(&g_rdma.lock);
927 	g_rdma.max_queue_depth = max_queue_depth;
928 	g_rdma.max_io_size = max_io_size;
929 	g_rdma.in_capsule_data_size = in_capsule_data_size;
930 
931 	g_rdma.event_channel = rdma_create_event_channel();
932 	if (g_rdma.event_channel == NULL) {
933 		SPDK_ERRLOG("rdma_create_event_channel() failed, %s\n", strerror(errno));
934 		pthread_mutex_unlock(&g_rdma.lock);
935 		return -1;
936 	}
937 
938 	rc = fcntl(g_rdma.event_channel->fd, F_SETFL, O_NONBLOCK);
939 	if (rc < 0) {
940 		SPDK_ERRLOG("fcntl to set fd to non-blocking failed\n");
941 		pthread_mutex_unlock(&g_rdma.lock);
942 		return -1;
943 	}
944 
945 	pthread_mutex_unlock(&g_rdma.lock);
946 	return 0;
947 }
948 
949 static void
950 spdk_nvmf_rdma_listen_addr_free(struct spdk_nvmf_rdma_listen_addr *addr)
951 {
952 	if (!addr) {
953 		return;
954 	}
955 
956 	free(addr->traddr);
957 	free(addr->trsvcid);
958 	free(addr);
959 }
960 static int
961 spdk_nvmf_rdma_fini(void)
962 {
963 	pthread_mutex_lock(&g_rdma.lock);
964 
965 	assert(TAILQ_EMPTY(&g_rdma.listen_addrs));
966 	if (g_rdma.event_channel != NULL) {
967 		rdma_destroy_event_channel(g_rdma.event_channel);
968 	}
969 	pthread_mutex_unlock(&g_rdma.lock);
970 
971 	return 0;
972 }
973 
974 static int
975 spdk_nvmf_rdma_listen_remove(struct spdk_nvmf_listen_addr *listen_addr)
976 {
977 	struct spdk_nvmf_rdma_listen_addr *addr, *tmp;
978 
979 	pthread_mutex_lock(&g_rdma.lock);
980 	TAILQ_FOREACH_SAFE(addr, &g_rdma.listen_addrs, link, tmp) {
981 		if ((!strcasecmp(addr->traddr, listen_addr->traddr)) &&
982 		    (!strcasecmp(addr->trsvcid, listen_addr->trsvcid))) {
983 			assert(addr->ref > 0);
984 			addr->ref--;
985 			if (!addr->ref) {
986 				TAILQ_REMOVE(&g_rdma.listen_addrs, addr, link);
987 				ibv_destroy_comp_channel(addr->comp_channel);
988 				rdma_destroy_id(addr->id);
989 				spdk_nvmf_rdma_listen_addr_free(addr);
990 			}
991 			break;
992 		}
993 	}
994 
995 	pthread_mutex_unlock(&g_rdma.lock);
996 	return 0;
997 }
998 
999 static int
1000 spdk_nvmf_rdma_poll(struct spdk_nvmf_conn *conn);
1001 
1002 static void
1003 spdk_nvmf_rdma_addr_listen_init(struct spdk_nvmf_rdma_listen_addr *addr)
1004 {
1005 	int rc;
1006 
1007 	rc = rdma_listen(addr->id, 10); /* 10 = backlog */
1008 	if (rc < 0) {
1009 		SPDK_ERRLOG("rdma_listen() failed\n");
1010 		addr->ref--;
1011 		assert(addr->ref == 0);
1012 		TAILQ_REMOVE(&g_rdma.listen_addrs, addr, link);
1013 		ibv_destroy_comp_channel(addr->comp_channel);
1014 		rdma_destroy_id(addr->id);
1015 		spdk_nvmf_rdma_listen_addr_free(addr);
1016 		return;
1017 	}
1018 
1019 	addr->is_listened = true;
1020 
1021 	SPDK_NOTICELOG("*** NVMf Target Listening on %s port %d ***\n",
1022 		       addr->traddr, ntohs(rdma_get_src_port(addr->id)));
1023 }
1024 
1025 static void
1026 spdk_nvmf_rdma_acceptor_poll(void)
1027 {
1028 	struct rdma_cm_event		*event;
1029 	int				rc;
1030 	struct spdk_nvmf_rdma_conn	*rdma_conn, *tmp;
1031 	struct spdk_nvmf_rdma_listen_addr *addr = NULL, *addr_tmp;
1032 
1033 	if (g_rdma.event_channel == NULL) {
1034 		return;
1035 	}
1036 
1037 	pthread_mutex_lock(&g_rdma.lock);
1038 	TAILQ_FOREACH_SAFE(addr, &g_rdma.listen_addrs, link, addr_tmp) {
1039 		if (!addr->is_listened) {
1040 			spdk_nvmf_rdma_addr_listen_init(addr);
1041 		}
1042 	}
1043 	pthread_mutex_unlock(&g_rdma.lock);
1044 
1045 	/* Process pending connections for incoming capsules. The only capsule
1046 	 * this should ever find is a CONNECT request. */
1047 	TAILQ_FOREACH_SAFE(rdma_conn, &g_pending_conns, link, tmp) {
1048 		rc = spdk_nvmf_rdma_poll(&rdma_conn->conn);
1049 		if (rc < 0) {
1050 			TAILQ_REMOVE(&g_pending_conns, rdma_conn, link);
1051 			spdk_nvmf_rdma_conn_destroy(rdma_conn);
1052 		} else if (rc > 0) {
1053 			/* At least one request was processed which is assumed to be
1054 			 * a CONNECT. Remove this connection from our list. */
1055 			TAILQ_REMOVE(&g_pending_conns, rdma_conn, link);
1056 		}
1057 	}
1058 
1059 	while (1) {
1060 		rc = rdma_get_cm_event(g_rdma.event_channel, &event);
1061 		if (rc == 0) {
1062 			SPDK_TRACELOG(SPDK_TRACE_RDMA, "Acceptor Event: %s\n", CM_EVENT_STR[event->event]);
1063 
1064 			switch (event->event) {
1065 			case RDMA_CM_EVENT_CONNECT_REQUEST:
1066 				rc = nvmf_rdma_connect(event);
1067 				if (rc < 0) {
1068 					SPDK_ERRLOG("Unable to process connect event. rc: %d\n", rc);
1069 					break;
1070 				}
1071 				break;
1072 			case RDMA_CM_EVENT_ESTABLISHED:
1073 				break;
1074 			case RDMA_CM_EVENT_ADDR_CHANGE:
1075 			case RDMA_CM_EVENT_DISCONNECTED:
1076 			case RDMA_CM_EVENT_DEVICE_REMOVAL:
1077 			case RDMA_CM_EVENT_TIMEWAIT_EXIT:
1078 				rc = nvmf_rdma_disconnect(event);
1079 				if (rc < 0) {
1080 					SPDK_ERRLOG("Unable to process disconnect event. rc: %d\n", rc);
1081 					break;
1082 				}
1083 				continue;
1084 			default:
1085 				SPDK_ERRLOG("Unexpected Acceptor Event [%d]\n", event->event);
1086 				break;
1087 			}
1088 
1089 			rdma_ack_cm_event(event);
1090 		} else {
1091 			if (errno != EAGAIN && errno != EWOULDBLOCK) {
1092 				SPDK_ERRLOG("Acceptor Event Error: %s\n", strerror(errno));
1093 			}
1094 			break;
1095 		}
1096 	}
1097 }
1098 
1099 static int
1100 spdk_nvmf_rdma_listen(struct spdk_nvmf_listen_addr *listen_addr)
1101 {
1102 	struct spdk_nvmf_rdma_listen_addr *addr;
1103 	struct sockaddr_in saddr;
1104 	int rc;
1105 
1106 	pthread_mutex_lock(&g_rdma.lock);
1107 	assert(g_rdma.event_channel != NULL);
1108 	TAILQ_FOREACH(addr, &g_rdma.listen_addrs, link) {
1109 		if ((!strcasecmp(addr->traddr, listen_addr->traddr)) &&
1110 		    (!strcasecmp(addr->trsvcid, listen_addr->trsvcid))) {
1111 			addr->ref++;
1112 			/* Already listening at this address */
1113 			pthread_mutex_unlock(&g_rdma.lock);
1114 			return 0;
1115 		}
1116 	}
1117 
1118 	addr = calloc(1, sizeof(*addr));
1119 	if (!addr) {
1120 		pthread_mutex_unlock(&g_rdma.lock);
1121 		return -1;
1122 	}
1123 
1124 	addr->traddr = strdup(listen_addr->traddr);
1125 	if (!addr->traddr) {
1126 		spdk_nvmf_rdma_listen_addr_free(addr);
1127 		pthread_mutex_unlock(&g_rdma.lock);
1128 		return -1;
1129 	}
1130 
1131 	addr->trsvcid = strdup(listen_addr->trsvcid);
1132 	if (!addr->trsvcid) {
1133 		spdk_nvmf_rdma_listen_addr_free(addr);
1134 		pthread_mutex_unlock(&g_rdma.lock);
1135 		return -1;
1136 	}
1137 
1138 	rc = rdma_create_id(g_rdma.event_channel, &addr->id, addr, RDMA_PS_TCP);
1139 	if (rc < 0) {
1140 		SPDK_ERRLOG("rdma_create_id() failed\n");
1141 		spdk_nvmf_rdma_listen_addr_free(addr);
1142 		pthread_mutex_unlock(&g_rdma.lock);
1143 		return -1;
1144 	}
1145 
1146 	memset(&saddr, 0, sizeof(saddr));
1147 	saddr.sin_family = AF_INET;
1148 	saddr.sin_addr.s_addr = inet_addr(addr->traddr);
1149 	saddr.sin_port = htons((uint16_t)strtoul(addr->trsvcid, NULL, 10));
1150 	rc = rdma_bind_addr(addr->id, (struct sockaddr *)&saddr);
1151 	if (rc < 0) {
1152 		SPDK_ERRLOG("rdma_bind_addr() failed\n");
1153 		rdma_destroy_id(addr->id);
1154 		spdk_nvmf_rdma_listen_addr_free(addr);
1155 		pthread_mutex_unlock(&g_rdma.lock);
1156 		return -1;
1157 	}
1158 
1159 	rc = ibv_query_device(addr->id->verbs, &addr->attr);
1160 	if (rc < 0) {
1161 		SPDK_ERRLOG("Failed to query RDMA device attributes.\n");
1162 		rdma_destroy_id(addr->id);
1163 		spdk_nvmf_rdma_listen_addr_free(addr);
1164 		pthread_mutex_unlock(&g_rdma.lock);
1165 		return -1;
1166 	}
1167 
1168 	addr->comp_channel = ibv_create_comp_channel(addr->id->verbs);
1169 	if (!addr->comp_channel) {
1170 		SPDK_ERRLOG("Failed to create completion channel\n");
1171 		rdma_destroy_id(addr->id);
1172 		spdk_nvmf_rdma_listen_addr_free(addr);
1173 		pthread_mutex_unlock(&g_rdma.lock);
1174 		return -1;
1175 	}
1176 	SPDK_TRACELOG(SPDK_TRACE_RDMA, "For listen id %p with context %p, created completion channel %p\n",
1177 		      addr->id, addr->id->verbs, addr->comp_channel);
1178 
1179 	rc = fcntl(addr->comp_channel->fd, F_SETFL, O_NONBLOCK);
1180 	if (rc < 0) {
1181 		SPDK_ERRLOG("fcntl to set comp channel to non-blocking failed\n");
1182 		rdma_destroy_id(addr->id);
1183 		ibv_destroy_comp_channel(addr->comp_channel);
1184 		spdk_nvmf_rdma_listen_addr_free(addr);
1185 		pthread_mutex_unlock(&g_rdma.lock);
1186 		return -1;
1187 	}
1188 
1189 
1190 	addr->ref = 1;
1191 	TAILQ_INSERT_TAIL(&g_rdma.listen_addrs, addr, link);
1192 	pthread_mutex_unlock(&g_rdma.lock);
1193 
1194 
1195 	return 0;
1196 }
1197 
1198 static void
1199 spdk_nvmf_rdma_discover(struct spdk_nvmf_listen_addr *listen_addr,
1200 			struct spdk_nvmf_discovery_log_page_entry *entry)
1201 {
1202 	entry->trtype = SPDK_NVMF_TRTYPE_RDMA;
1203 	entry->adrfam = SPDK_NVMF_ADRFAM_IPV4;
1204 	entry->treq.secure_channel = SPDK_NVMF_TREQ_SECURE_CHANNEL_NOT_SPECIFIED;
1205 
1206 	spdk_strcpy_pad(entry->trsvcid, listen_addr->trsvcid, sizeof(entry->trsvcid), ' ');
1207 	spdk_strcpy_pad(entry->traddr, listen_addr->traddr, sizeof(entry->traddr), ' ');
1208 
1209 	entry->tsas.rdma.rdma_qptype = SPDK_NVMF_RDMA_QPTYPE_RELIABLE_CONNECTED;
1210 	entry->tsas.rdma.rdma_prtype = SPDK_NVMF_RDMA_PRTYPE_NONE;
1211 	entry->tsas.rdma.rdma_cms = SPDK_NVMF_RDMA_CMS_RDMA_CM;
1212 }
1213 
1214 static struct spdk_nvmf_session *
1215 spdk_nvmf_rdma_session_init(void)
1216 {
1217 	struct spdk_nvmf_rdma_session	*rdma_sess;
1218 	int				i;
1219 	struct spdk_nvmf_rdma_buf	*buf;
1220 
1221 	rdma_sess = calloc(1, sizeof(*rdma_sess));
1222 	if (!rdma_sess) {
1223 		return NULL;
1224 	}
1225 
1226 	/* TODO: Make the number of elements in this pool configurable. For now, one full queue
1227 	 *       worth seems reasonable.
1228 	 */
1229 	rdma_sess->buf = spdk_zmalloc(g_rdma.max_queue_depth * g_rdma.max_io_size,
1230 				      0x20000, NULL);
1231 	if (!rdma_sess->buf) {
1232 		SPDK_ERRLOG("Large buffer pool allocation failed (%d x %d)\n",
1233 			    g_rdma.max_queue_depth, g_rdma.max_io_size);
1234 		free(rdma_sess);
1235 		return NULL;
1236 	}
1237 
1238 	SLIST_INIT(&rdma_sess->data_buf_pool);
1239 	for (i = 0; i < g_rdma.max_queue_depth; i++) {
1240 		buf = (struct spdk_nvmf_rdma_buf *)(rdma_sess->buf + (i * g_rdma.max_io_size));
1241 		SLIST_INSERT_HEAD(&rdma_sess->data_buf_pool, buf, link);
1242 	}
1243 
1244 	rdma_sess->session.transport = &spdk_nvmf_transport_rdma;
1245 
1246 	return &rdma_sess->session;
1247 }
1248 
1249 static void
1250 spdk_nvmf_rdma_session_fini(struct spdk_nvmf_session *session)
1251 {
1252 	struct spdk_nvmf_rdma_session *rdma_sess = get_rdma_sess(session);
1253 
1254 	if (!rdma_sess) {
1255 		return;
1256 	}
1257 
1258 	ibv_dereg_mr(rdma_sess->buf_mr);
1259 	spdk_free(rdma_sess->buf);
1260 	free(rdma_sess);
1261 }
1262 
1263 static int
1264 spdk_nvmf_rdma_session_add_conn(struct spdk_nvmf_session *session,
1265 				struct spdk_nvmf_conn *conn)
1266 {
1267 	struct spdk_nvmf_rdma_session	*rdma_sess = get_rdma_sess(session);
1268 	struct spdk_nvmf_rdma_conn	*rdma_conn = get_rdma_conn(conn);
1269 
1270 	if (rdma_sess->verbs != NULL) {
1271 		if (rdma_sess->verbs != rdma_conn->cm_id->verbs) {
1272 			SPDK_ERRLOG("Two connections belonging to the same session cannot connect using different RDMA devices.\n");
1273 			return -1;
1274 		}
1275 
1276 		/* Nothing else to do. */
1277 		return 0;
1278 	}
1279 
1280 	rdma_sess->verbs = rdma_conn->cm_id->verbs;
1281 	rdma_sess->buf_mr = ibv_reg_mr(rdma_conn->cm_id->pd, rdma_sess->buf,
1282 				       g_rdma.max_queue_depth * g_rdma.max_io_size,
1283 				       IBV_ACCESS_LOCAL_WRITE |
1284 				       IBV_ACCESS_REMOTE_WRITE);
1285 	if (!rdma_sess->buf_mr) {
1286 		SPDK_ERRLOG("Large buffer pool registration failed (%d x %d)\n",
1287 			    g_rdma.max_queue_depth, g_rdma.max_io_size);
1288 		spdk_free(rdma_sess->buf);
1289 		free(rdma_sess);
1290 		return -1;
1291 	}
1292 
1293 	SPDK_TRACELOG(SPDK_TRACE_RDMA, "Session Shared Data Pool: %p Length: %x LKey: %x\n",
1294 		      rdma_sess->buf,  g_rdma.max_queue_depth * g_rdma.max_io_size, rdma_sess->buf_mr->lkey);
1295 
1296 	return 0;
1297 }
1298 
1299 static int
1300 spdk_nvmf_rdma_session_remove_conn(struct spdk_nvmf_session *session,
1301 				   struct spdk_nvmf_conn *conn)
1302 {
1303 	return 0;
1304 }
1305 
1306 static int
1307 spdk_nvmf_rdma_request_complete(struct spdk_nvmf_request *req)
1308 {
1309 	struct spdk_nvme_cpl *rsp = &req->rsp->nvme_cpl;
1310 	int rc;
1311 
1312 	if (rsp->status.sc == SPDK_NVME_SC_SUCCESS &&
1313 	    req->xfer == SPDK_NVME_DATA_CONTROLLER_TO_HOST) {
1314 		rc = spdk_nvmf_rdma_request_transfer_data(req);
1315 	} else {
1316 		rc = request_transfer_out(req);
1317 	}
1318 
1319 	return rc;
1320 }
1321 
1322 static void
1323 request_release_buffer(struct spdk_nvmf_request *req)
1324 {
1325 	struct spdk_nvmf_rdma_request	*rdma_req = get_rdma_req(req);
1326 	struct spdk_nvmf_conn		*conn = req->conn;
1327 	struct spdk_nvmf_rdma_session	*rdma_sess;
1328 	struct spdk_nvmf_rdma_buf	*buf;
1329 
1330 	if (rdma_req->data_from_pool) {
1331 		/* Put the buffer back in the pool */
1332 		rdma_sess = get_rdma_sess(conn->sess);
1333 		buf = req->data;
1334 
1335 		SLIST_INSERT_HEAD(&rdma_sess->data_buf_pool, buf, link);
1336 		req->data = NULL;
1337 		req->length = 0;
1338 		rdma_req->data_from_pool = false;
1339 	}
1340 }
1341 
1342 static void
1343 spdk_nvmf_rdma_close_conn(struct spdk_nvmf_conn *conn)
1344 {
1345 	spdk_nvmf_rdma_conn_destroy(get_rdma_conn(conn));
1346 }
1347 
1348 static int
1349 process_incoming_queue(struct spdk_nvmf_rdma_conn *rdma_conn)
1350 {
1351 	struct spdk_nvmf_rdma_recv	*rdma_recv, *tmp;
1352 	struct spdk_nvmf_rdma_request	*rdma_req;
1353 	struct spdk_nvmf_request	*req;
1354 	int rc, count;
1355 	bool error = false;
1356 
1357 	count = 0;
1358 	TAILQ_FOREACH_SAFE(rdma_recv, &rdma_conn->incoming_queue, link, tmp) {
1359 		rdma_req = TAILQ_FIRST(&rdma_conn->free_queue);
1360 		if (rdma_req == NULL) {
1361 			/* Need to wait for more SEND completions */
1362 			break;
1363 		}
1364 		TAILQ_REMOVE(&rdma_conn->free_queue, rdma_req, link);
1365 		TAILQ_REMOVE(&rdma_conn->incoming_queue, rdma_recv, link);
1366 		rdma_req->recv = rdma_recv;
1367 		req = &rdma_req->req;
1368 
1369 		/* The first element of the SGL is the NVMe command */
1370 		req->cmd = (union nvmf_h2c_msg *)rdma_recv->sgl[0].addr;
1371 
1372 		spdk_trace_record(TRACE_NVMF_IO_START, 0, 0, (uint64_t)req, 0);
1373 
1374 		memset(req->rsp, 0, sizeof(*req->rsp));
1375 		rc = spdk_nvmf_request_prep_data(req);
1376 		switch (rc) {
1377 		case SPDK_NVMF_REQUEST_PREP_READY:
1378 			SPDK_TRACELOG(SPDK_TRACE_RDMA, "Request %p is ready for execution\n", req);
1379 			/* Data is immediately available */
1380 			rc = spdk_nvmf_request_exec(req);
1381 			if (rc < 0) {
1382 				error = true;
1383 				continue;
1384 			}
1385 			count++;
1386 			break;
1387 		case SPDK_NVMF_REQUEST_PREP_PENDING_BUFFER:
1388 			SPDK_TRACELOG(SPDK_TRACE_RDMA, "Request %p needs data buffer\n", req);
1389 			TAILQ_INSERT_TAIL(&rdma_conn->pending_data_buf_queue, rdma_req, link);
1390 			break;
1391 		case SPDK_NVMF_REQUEST_PREP_PENDING_DATA:
1392 			SPDK_TRACELOG(SPDK_TRACE_RDMA, "Request %p needs data transfer\n", req);
1393 			rc = spdk_nvmf_rdma_request_transfer_data(req);
1394 			if (rc < 0) {
1395 				error = true;
1396 				continue;
1397 			}
1398 			break;
1399 		case SPDK_NVMF_REQUEST_PREP_ERROR:
1400 			spdk_nvmf_request_complete(req);
1401 			break;
1402 		}
1403 	}
1404 
1405 	if (error) {
1406 		return -1;
1407 	}
1408 
1409 	return count;
1410 }
1411 
1412 static struct spdk_nvmf_rdma_request *
1413 get_rdma_req_from_wc(struct spdk_nvmf_rdma_conn *rdma_conn,
1414 		     struct ibv_wc *wc)
1415 {
1416 	struct spdk_nvmf_rdma_request *rdma_req;
1417 
1418 	rdma_req = (struct spdk_nvmf_rdma_request *)wc->wr_id;
1419 	assert(rdma_req != NULL);
1420 	assert(rdma_req - rdma_conn->reqs >= 0);
1421 	assert(rdma_req - rdma_conn->reqs < (ptrdiff_t)rdma_conn->max_queue_depth);
1422 
1423 	return rdma_req;
1424 }
1425 
1426 static struct spdk_nvmf_rdma_recv *
1427 get_rdma_recv_from_wc(struct spdk_nvmf_rdma_conn *rdma_conn,
1428 		      struct ibv_wc *wc)
1429 {
1430 	struct spdk_nvmf_rdma_recv *rdma_recv;
1431 
1432 	assert(wc->byte_len >= sizeof(struct spdk_nvmf_capsule_cmd));
1433 
1434 	rdma_recv = (struct spdk_nvmf_rdma_recv *)wc->wr_id;
1435 	assert(rdma_recv != NULL);
1436 	assert(rdma_recv - rdma_conn->recvs >= 0);
1437 	assert(rdma_recv - rdma_conn->recvs < (ptrdiff_t)rdma_conn->max_queue_depth);
1438 #ifdef DEBUG
1439 	assert(rdma_recv->in_use == false);
1440 	rdma_recv->in_use = true;
1441 #endif
1442 
1443 	return rdma_recv;
1444 }
1445 
1446 /* Returns the number of times that spdk_nvmf_request_exec was called,
1447  * or -1 on error.
1448  */
1449 static int
1450 spdk_nvmf_rdma_poll(struct spdk_nvmf_conn *conn)
1451 {
1452 	struct ibv_wc wc[32];
1453 	struct spdk_nvmf_rdma_conn *rdma_conn = get_rdma_conn(conn);
1454 	struct spdk_nvmf_rdma_request *rdma_req;
1455 	struct spdk_nvmf_rdma_recv    *rdma_recv;
1456 	struct spdk_nvmf_request *req;
1457 	int reaped, i, rc;
1458 	int count = 0;
1459 	bool error = false;
1460 
1461 	/* Poll for completing operations. */
1462 	rc = ibv_poll_cq(rdma_conn->cq, 32, wc);
1463 	if (rc < 0) {
1464 		SPDK_ERRLOG("Error polling CQ! (%d): %s\n",
1465 			    errno, strerror(errno));
1466 		return -1;
1467 	}
1468 
1469 	reaped = rc;
1470 	for (i = 0; i < reaped; i++) {
1471 		if (wc[i].status) {
1472 			SPDK_ERRLOG("CQ error on Connection %p, Request 0x%lu (%d): %s\n",
1473 				    conn, wc[i].wr_id, wc[i].status, ibv_wc_status_str(wc[i].status));
1474 			error = true;
1475 			continue;
1476 		}
1477 
1478 		switch (wc[i].opcode) {
1479 		case IBV_WC_SEND:
1480 			rdma_req = get_rdma_req_from_wc(rdma_conn, &wc[i]);
1481 			req = &rdma_req->req;
1482 
1483 			assert(rdma_conn->cur_queue_depth > 0);
1484 			SPDK_TRACELOG(SPDK_TRACE_RDMA,
1485 				      "RDMA SEND Complete. Request: %p Connection: %p Outstanding I/O: %d\n",
1486 				      req, conn, rdma_conn->cur_queue_depth - 1);
1487 			rdma_conn->cur_queue_depth--;
1488 
1489 			/* The request may still own a data buffer. Release it */
1490 			request_release_buffer(req);
1491 
1492 			/* Put the request back on the free list */
1493 			TAILQ_INSERT_TAIL(&rdma_conn->free_queue, rdma_req, link);
1494 
1495 			/* Try to process queued incoming requests */
1496 			rc = process_incoming_queue(rdma_conn);
1497 			if (rc < 0) {
1498 				error = true;
1499 				continue;
1500 			}
1501 			count += rc;
1502 			break;
1503 
1504 		case IBV_WC_RDMA_WRITE:
1505 			rdma_req = get_rdma_req_from_wc(rdma_conn, &wc[i]);
1506 			req = &rdma_req->req;
1507 
1508 			SPDK_TRACELOG(SPDK_TRACE_RDMA, "RDMA WRITE Complete. Request: %p Connection: %p\n",
1509 				      req, conn);
1510 			spdk_trace_record(TRACE_RDMA_WRITE_COMPLETE, 0, 0, (uint64_t)req, 0);
1511 
1512 			/* Now that the write has completed, the data buffer can be released */
1513 			request_release_buffer(req);
1514 
1515 			rdma_conn->cur_rdma_rw_depth--;
1516 
1517 			/* Since an RDMA R/W operation completed, try to submit from the pending list. */
1518 			rc = spdk_nvmf_rdma_handle_pending_rdma_rw(conn);
1519 			if (rc < 0) {
1520 				error = true;
1521 				continue;
1522 			}
1523 			count += rc;
1524 			break;
1525 
1526 		case IBV_WC_RDMA_READ:
1527 			rdma_req = get_rdma_req_from_wc(rdma_conn, &wc[i]);
1528 			req = &rdma_req->req;
1529 
1530 			SPDK_TRACELOG(SPDK_TRACE_RDMA, "RDMA READ Complete. Request: %p Connection: %p\n",
1531 				      req, conn);
1532 			spdk_trace_record(TRACE_RDMA_READ_COMPLETE, 0, 0, (uint64_t)req, 0);
1533 			rc = spdk_nvmf_request_exec(req);
1534 			if (rc) {
1535 				error = true;
1536 				continue;
1537 			}
1538 			count++;
1539 
1540 			/* Since an RDMA R/W operation completed, try to submit from the pending list. */
1541 			rdma_conn->cur_rdma_rw_depth--;
1542 			rc = spdk_nvmf_rdma_handle_pending_rdma_rw(conn);
1543 			if (rc < 0) {
1544 				error = true;
1545 				continue;
1546 			}
1547 			count += rc;
1548 			break;
1549 
1550 		case IBV_WC_RECV:
1551 			rdma_recv = get_rdma_recv_from_wc(rdma_conn, &wc[i]);
1552 
1553 			rdma_conn->cur_queue_depth++;
1554 			if (rdma_conn->cur_queue_depth > rdma_conn->max_queue_depth) {
1555 				SPDK_TRACELOG(SPDK_TRACE_RDMA,
1556 					      "Temporarily exceeded maximum queue depth (%u). Queueing.\n",
1557 					      rdma_conn->cur_queue_depth);
1558 			}
1559 			SPDK_TRACELOG(SPDK_TRACE_RDMA,
1560 				      "RDMA RECV Complete. Recv: %p Connection: %p Outstanding I/O: %d\n",
1561 				      rdma_recv, conn, rdma_conn->cur_queue_depth);
1562 
1563 			TAILQ_INSERT_TAIL(&rdma_conn->incoming_queue, rdma_recv, link);
1564 			rc = process_incoming_queue(rdma_conn);
1565 			if (rc < 0) {
1566 				error = true;
1567 				continue;
1568 			}
1569 			count += rc;
1570 			break;
1571 
1572 		default:
1573 			SPDK_ERRLOG("Received an unknown opcode on the CQ: %d\n", wc[i].opcode);
1574 			error = true;
1575 			continue;
1576 		}
1577 	}
1578 
1579 	if (error == true) {
1580 		return -1;
1581 	}
1582 
1583 	return count;
1584 }
1585 
1586 static bool
1587 spdk_nvmf_rdma_conn_is_idle(struct spdk_nvmf_conn *conn)
1588 {
1589 	struct spdk_nvmf_rdma_conn *rdma_conn = get_rdma_conn(conn);
1590 
1591 	if (rdma_conn->cur_queue_depth == 0 && rdma_conn->cur_rdma_rw_depth == 0) {
1592 		return true;
1593 	}
1594 	return false;
1595 }
1596 
1597 const struct spdk_nvmf_transport spdk_nvmf_transport_rdma = {
1598 	.name = "rdma",
1599 	.transport_init = spdk_nvmf_rdma_init,
1600 	.transport_fini = spdk_nvmf_rdma_fini,
1601 
1602 	.acceptor_poll = spdk_nvmf_rdma_acceptor_poll,
1603 
1604 	.listen_addr_add = spdk_nvmf_rdma_listen,
1605 	.listen_addr_remove = spdk_nvmf_rdma_listen_remove,
1606 	.listen_addr_discover = spdk_nvmf_rdma_discover,
1607 
1608 	.session_init = spdk_nvmf_rdma_session_init,
1609 	.session_fini = spdk_nvmf_rdma_session_fini,
1610 	.session_add_conn = spdk_nvmf_rdma_session_add_conn,
1611 	.session_remove_conn = spdk_nvmf_rdma_session_remove_conn,
1612 
1613 	.req_complete = spdk_nvmf_rdma_request_complete,
1614 
1615 	.conn_fini = spdk_nvmf_rdma_close_conn,
1616 	.conn_poll = spdk_nvmf_rdma_poll,
1617 	.conn_is_idle = spdk_nvmf_rdma_conn_is_idle,
1618 
1619 };
1620 
1621 SPDK_LOG_REGISTER_TRACE_FLAG("rdma", SPDK_TRACE_RDMA)
1622