xref: /linux/drivers/nvme/target/rdma.c (revision 071bf69a0220253a44acb8b2a27f7a262b9a46bf)
1 /*
2  * NVMe over Fabrics RDMA target.
3  * Copyright (c) 2015-2016 HGST, a Western Digital Company.
4  *
5  * This program is free software; you can redistribute it and/or modify it
6  * under the terms and conditions of the GNU General Public License,
7  * version 2, as published by the Free Software Foundation.
8  *
9  * This program is distributed in the hope it will be useful, but WITHOUT
10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
12  * more details.
13  */
14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15 #include <linux/atomic.h>
16 #include <linux/ctype.h>
17 #include <linux/delay.h>
18 #include <linux/err.h>
19 #include <linux/init.h>
20 #include <linux/module.h>
21 #include <linux/nvme.h>
22 #include <linux/slab.h>
23 #include <linux/string.h>
24 #include <linux/wait.h>
25 #include <linux/inet.h>
26 #include <asm/unaligned.h>
27 
28 #include <rdma/ib_verbs.h>
29 #include <rdma/rdma_cm.h>
30 #include <rdma/rw.h>
31 
32 #include <linux/nvme-rdma.h>
33 #include "nvmet.h"
34 
35 /*
36  * We allow up to a page of inline data to go with the SQE
37  */
38 #define NVMET_RDMA_INLINE_DATA_SIZE	PAGE_SIZE
39 
40 struct nvmet_rdma_cmd {
41 	struct ib_sge		sge[2];
42 	struct ib_cqe		cqe;
43 	struct ib_recv_wr	wr;
44 	struct scatterlist	inline_sg;
45 	struct page		*inline_page;
46 	struct nvme_command     *nvme_cmd;
47 	struct nvmet_rdma_queue	*queue;
48 };
49 
50 enum {
51 	NVMET_RDMA_REQ_INLINE_DATA	= (1 << 0),
52 	NVMET_RDMA_REQ_INVALIDATE_RKEY	= (1 << 1),
53 };
54 
55 struct nvmet_rdma_rsp {
56 	struct ib_sge		send_sge;
57 	struct ib_cqe		send_cqe;
58 	struct ib_send_wr	send_wr;
59 
60 	struct nvmet_rdma_cmd	*cmd;
61 	struct nvmet_rdma_queue	*queue;
62 
63 	struct ib_cqe		read_cqe;
64 	struct rdma_rw_ctx	rw;
65 
66 	struct nvmet_req	req;
67 
68 	u8			n_rdma;
69 	u32			flags;
70 	u32			invalidate_rkey;
71 
72 	struct list_head	wait_list;
73 	struct list_head	free_list;
74 };
75 
76 enum nvmet_rdma_queue_state {
77 	NVMET_RDMA_Q_CONNECTING,
78 	NVMET_RDMA_Q_LIVE,
79 	NVMET_RDMA_Q_DISCONNECTING,
80 };
81 
82 struct nvmet_rdma_queue {
83 	struct rdma_cm_id	*cm_id;
84 	struct nvmet_port	*port;
85 	struct ib_cq		*cq;
86 	atomic_t		sq_wr_avail;
87 	struct nvmet_rdma_device *dev;
88 	spinlock_t		state_lock;
89 	enum nvmet_rdma_queue_state state;
90 	struct nvmet_cq		nvme_cq;
91 	struct nvmet_sq		nvme_sq;
92 
93 	struct nvmet_rdma_rsp	*rsps;
94 	struct list_head	free_rsps;
95 	spinlock_t		rsps_lock;
96 	struct nvmet_rdma_cmd	*cmds;
97 
98 	struct work_struct	release_work;
99 	struct list_head	rsp_wait_list;
100 	struct list_head	rsp_wr_wait_list;
101 	spinlock_t		rsp_wr_wait_lock;
102 
103 	int			idx;
104 	int			host_qid;
105 	int			recv_queue_size;
106 	int			send_queue_size;
107 
108 	struct list_head	queue_list;
109 };
110 
111 struct nvmet_rdma_device {
112 	struct ib_device	*device;
113 	struct ib_pd		*pd;
114 	struct ib_srq		*srq;
115 	struct nvmet_rdma_cmd	*srq_cmds;
116 	size_t			srq_size;
117 	struct kref		ref;
118 	struct list_head	entry;
119 };
120 
121 static bool nvmet_rdma_use_srq;
122 module_param_named(use_srq, nvmet_rdma_use_srq, bool, 0444);
123 MODULE_PARM_DESC(use_srq, "Use shared receive queue.");
124 
125 static DEFINE_IDA(nvmet_rdma_queue_ida);
126 static LIST_HEAD(nvmet_rdma_queue_list);
127 static DEFINE_MUTEX(nvmet_rdma_queue_mutex);
128 
129 static LIST_HEAD(device_list);
130 static DEFINE_MUTEX(device_list_mutex);
131 
132 static bool nvmet_rdma_execute_command(struct nvmet_rdma_rsp *rsp);
133 static void nvmet_rdma_send_done(struct ib_cq *cq, struct ib_wc *wc);
134 static void nvmet_rdma_recv_done(struct ib_cq *cq, struct ib_wc *wc);
135 static void nvmet_rdma_read_data_done(struct ib_cq *cq, struct ib_wc *wc);
136 static void nvmet_rdma_qp_event(struct ib_event *event, void *priv);
137 static void nvmet_rdma_queue_disconnect(struct nvmet_rdma_queue *queue);
138 
139 static struct nvmet_fabrics_ops nvmet_rdma_ops;
140 
141 /* XXX: really should move to a generic header sooner or later.. */
142 static inline u32 get_unaligned_le24(const u8 *p)
143 {
144 	return (u32)p[0] | (u32)p[1] << 8 | (u32)p[2] << 16;
145 }
146 
147 static inline bool nvmet_rdma_need_data_in(struct nvmet_rdma_rsp *rsp)
148 {
149 	return nvme_is_write(rsp->req.cmd) &&
150 		rsp->req.data_len &&
151 		!(rsp->flags & NVMET_RDMA_REQ_INLINE_DATA);
152 }
153 
154 static inline bool nvmet_rdma_need_data_out(struct nvmet_rdma_rsp *rsp)
155 {
156 	return !nvme_is_write(rsp->req.cmd) &&
157 		rsp->req.data_len &&
158 		!rsp->req.rsp->status &&
159 		!(rsp->flags & NVMET_RDMA_REQ_INLINE_DATA);
160 }
161 
162 static inline struct nvmet_rdma_rsp *
163 nvmet_rdma_get_rsp(struct nvmet_rdma_queue *queue)
164 {
165 	struct nvmet_rdma_rsp *rsp;
166 	unsigned long flags;
167 
168 	spin_lock_irqsave(&queue->rsps_lock, flags);
169 	rsp = list_first_entry(&queue->free_rsps,
170 				struct nvmet_rdma_rsp, free_list);
171 	list_del(&rsp->free_list);
172 	spin_unlock_irqrestore(&queue->rsps_lock, flags);
173 
174 	return rsp;
175 }
176 
177 static inline void
178 nvmet_rdma_put_rsp(struct nvmet_rdma_rsp *rsp)
179 {
180 	unsigned long flags;
181 
182 	spin_lock_irqsave(&rsp->queue->rsps_lock, flags);
183 	list_add_tail(&rsp->free_list, &rsp->queue->free_rsps);
184 	spin_unlock_irqrestore(&rsp->queue->rsps_lock, flags);
185 }
186 
187 static void nvmet_rdma_free_sgl(struct scatterlist *sgl, unsigned int nents)
188 {
189 	struct scatterlist *sg;
190 	int count;
191 
192 	if (!sgl || !nents)
193 		return;
194 
195 	for_each_sg(sgl, sg, nents, count)
196 		__free_page(sg_page(sg));
197 	kfree(sgl);
198 }
199 
200 static int nvmet_rdma_alloc_sgl(struct scatterlist **sgl, unsigned int *nents,
201 		u32 length)
202 {
203 	struct scatterlist *sg;
204 	struct page *page;
205 	unsigned int nent;
206 	int i = 0;
207 
208 	nent = DIV_ROUND_UP(length, PAGE_SIZE);
209 	sg = kmalloc_array(nent, sizeof(struct scatterlist), GFP_KERNEL);
210 	if (!sg)
211 		goto out;
212 
213 	sg_init_table(sg, nent);
214 
215 	while (length) {
216 		u32 page_len = min_t(u32, length, PAGE_SIZE);
217 
218 		page = alloc_page(GFP_KERNEL);
219 		if (!page)
220 			goto out_free_pages;
221 
222 		sg_set_page(&sg[i], page, page_len, 0);
223 		length -= page_len;
224 		i++;
225 	}
226 	*sgl = sg;
227 	*nents = nent;
228 	return 0;
229 
230 out_free_pages:
231 	while (i > 0) {
232 		i--;
233 		__free_page(sg_page(&sg[i]));
234 	}
235 	kfree(sg);
236 out:
237 	return NVME_SC_INTERNAL;
238 }
239 
240 static int nvmet_rdma_alloc_cmd(struct nvmet_rdma_device *ndev,
241 			struct nvmet_rdma_cmd *c, bool admin)
242 {
243 	/* NVMe command / RDMA RECV */
244 	c->nvme_cmd = kmalloc(sizeof(*c->nvme_cmd), GFP_KERNEL);
245 	if (!c->nvme_cmd)
246 		goto out;
247 
248 	c->sge[0].addr = ib_dma_map_single(ndev->device, c->nvme_cmd,
249 			sizeof(*c->nvme_cmd), DMA_FROM_DEVICE);
250 	if (ib_dma_mapping_error(ndev->device, c->sge[0].addr))
251 		goto out_free_cmd;
252 
253 	c->sge[0].length = sizeof(*c->nvme_cmd);
254 	c->sge[0].lkey = ndev->pd->local_dma_lkey;
255 
256 	if (!admin) {
257 		c->inline_page = alloc_pages(GFP_KERNEL,
258 				get_order(NVMET_RDMA_INLINE_DATA_SIZE));
259 		if (!c->inline_page)
260 			goto out_unmap_cmd;
261 		c->sge[1].addr = ib_dma_map_page(ndev->device,
262 				c->inline_page, 0, NVMET_RDMA_INLINE_DATA_SIZE,
263 				DMA_FROM_DEVICE);
264 		if (ib_dma_mapping_error(ndev->device, c->sge[1].addr))
265 			goto out_free_inline_page;
266 		c->sge[1].length = NVMET_RDMA_INLINE_DATA_SIZE;
267 		c->sge[1].lkey = ndev->pd->local_dma_lkey;
268 	}
269 
270 	c->cqe.done = nvmet_rdma_recv_done;
271 
272 	c->wr.wr_cqe = &c->cqe;
273 	c->wr.sg_list = c->sge;
274 	c->wr.num_sge = admin ? 1 : 2;
275 
276 	return 0;
277 
278 out_free_inline_page:
279 	if (!admin) {
280 		__free_pages(c->inline_page,
281 				get_order(NVMET_RDMA_INLINE_DATA_SIZE));
282 	}
283 out_unmap_cmd:
284 	ib_dma_unmap_single(ndev->device, c->sge[0].addr,
285 			sizeof(*c->nvme_cmd), DMA_FROM_DEVICE);
286 out_free_cmd:
287 	kfree(c->nvme_cmd);
288 
289 out:
290 	return -ENOMEM;
291 }
292 
293 static void nvmet_rdma_free_cmd(struct nvmet_rdma_device *ndev,
294 		struct nvmet_rdma_cmd *c, bool admin)
295 {
296 	if (!admin) {
297 		ib_dma_unmap_page(ndev->device, c->sge[1].addr,
298 				NVMET_RDMA_INLINE_DATA_SIZE, DMA_FROM_DEVICE);
299 		__free_pages(c->inline_page,
300 				get_order(NVMET_RDMA_INLINE_DATA_SIZE));
301 	}
302 	ib_dma_unmap_single(ndev->device, c->sge[0].addr,
303 				sizeof(*c->nvme_cmd), DMA_FROM_DEVICE);
304 	kfree(c->nvme_cmd);
305 }
306 
307 static struct nvmet_rdma_cmd *
308 nvmet_rdma_alloc_cmds(struct nvmet_rdma_device *ndev,
309 		int nr_cmds, bool admin)
310 {
311 	struct nvmet_rdma_cmd *cmds;
312 	int ret = -EINVAL, i;
313 
314 	cmds = kcalloc(nr_cmds, sizeof(struct nvmet_rdma_cmd), GFP_KERNEL);
315 	if (!cmds)
316 		goto out;
317 
318 	for (i = 0; i < nr_cmds; i++) {
319 		ret = nvmet_rdma_alloc_cmd(ndev, cmds + i, admin);
320 		if (ret)
321 			goto out_free;
322 	}
323 
324 	return cmds;
325 
326 out_free:
327 	while (--i >= 0)
328 		nvmet_rdma_free_cmd(ndev, cmds + i, admin);
329 	kfree(cmds);
330 out:
331 	return ERR_PTR(ret);
332 }
333 
334 static void nvmet_rdma_free_cmds(struct nvmet_rdma_device *ndev,
335 		struct nvmet_rdma_cmd *cmds, int nr_cmds, bool admin)
336 {
337 	int i;
338 
339 	for (i = 0; i < nr_cmds; i++)
340 		nvmet_rdma_free_cmd(ndev, cmds + i, admin);
341 	kfree(cmds);
342 }
343 
344 static int nvmet_rdma_alloc_rsp(struct nvmet_rdma_device *ndev,
345 		struct nvmet_rdma_rsp *r)
346 {
347 	/* NVMe CQE / RDMA SEND */
348 	r->req.rsp = kmalloc(sizeof(*r->req.rsp), GFP_KERNEL);
349 	if (!r->req.rsp)
350 		goto out;
351 
352 	r->send_sge.addr = ib_dma_map_single(ndev->device, r->req.rsp,
353 			sizeof(*r->req.rsp), DMA_TO_DEVICE);
354 	if (ib_dma_mapping_error(ndev->device, r->send_sge.addr))
355 		goto out_free_rsp;
356 
357 	r->send_sge.length = sizeof(*r->req.rsp);
358 	r->send_sge.lkey = ndev->pd->local_dma_lkey;
359 
360 	r->send_cqe.done = nvmet_rdma_send_done;
361 
362 	r->send_wr.wr_cqe = &r->send_cqe;
363 	r->send_wr.sg_list = &r->send_sge;
364 	r->send_wr.num_sge = 1;
365 	r->send_wr.send_flags = IB_SEND_SIGNALED;
366 
367 	/* Data In / RDMA READ */
368 	r->read_cqe.done = nvmet_rdma_read_data_done;
369 	return 0;
370 
371 out_free_rsp:
372 	kfree(r->req.rsp);
373 out:
374 	return -ENOMEM;
375 }
376 
377 static void nvmet_rdma_free_rsp(struct nvmet_rdma_device *ndev,
378 		struct nvmet_rdma_rsp *r)
379 {
380 	ib_dma_unmap_single(ndev->device, r->send_sge.addr,
381 				sizeof(*r->req.rsp), DMA_TO_DEVICE);
382 	kfree(r->req.rsp);
383 }
384 
385 static int
386 nvmet_rdma_alloc_rsps(struct nvmet_rdma_queue *queue)
387 {
388 	struct nvmet_rdma_device *ndev = queue->dev;
389 	int nr_rsps = queue->recv_queue_size * 2;
390 	int ret = -EINVAL, i;
391 
392 	queue->rsps = kcalloc(nr_rsps, sizeof(struct nvmet_rdma_rsp),
393 			GFP_KERNEL);
394 	if (!queue->rsps)
395 		goto out;
396 
397 	for (i = 0; i < nr_rsps; i++) {
398 		struct nvmet_rdma_rsp *rsp = &queue->rsps[i];
399 
400 		ret = nvmet_rdma_alloc_rsp(ndev, rsp);
401 		if (ret)
402 			goto out_free;
403 
404 		list_add_tail(&rsp->free_list, &queue->free_rsps);
405 	}
406 
407 	return 0;
408 
409 out_free:
410 	while (--i >= 0) {
411 		struct nvmet_rdma_rsp *rsp = &queue->rsps[i];
412 
413 		list_del(&rsp->free_list);
414 		nvmet_rdma_free_rsp(ndev, rsp);
415 	}
416 	kfree(queue->rsps);
417 out:
418 	return ret;
419 }
420 
421 static void nvmet_rdma_free_rsps(struct nvmet_rdma_queue *queue)
422 {
423 	struct nvmet_rdma_device *ndev = queue->dev;
424 	int i, nr_rsps = queue->recv_queue_size * 2;
425 
426 	for (i = 0; i < nr_rsps; i++) {
427 		struct nvmet_rdma_rsp *rsp = &queue->rsps[i];
428 
429 		list_del(&rsp->free_list);
430 		nvmet_rdma_free_rsp(ndev, rsp);
431 	}
432 	kfree(queue->rsps);
433 }
434 
435 static int nvmet_rdma_post_recv(struct nvmet_rdma_device *ndev,
436 		struct nvmet_rdma_cmd *cmd)
437 {
438 	struct ib_recv_wr *bad_wr;
439 
440 	if (ndev->srq)
441 		return ib_post_srq_recv(ndev->srq, &cmd->wr, &bad_wr);
442 	return ib_post_recv(cmd->queue->cm_id->qp, &cmd->wr, &bad_wr);
443 }
444 
445 static void nvmet_rdma_process_wr_wait_list(struct nvmet_rdma_queue *queue)
446 {
447 	spin_lock(&queue->rsp_wr_wait_lock);
448 	while (!list_empty(&queue->rsp_wr_wait_list)) {
449 		struct nvmet_rdma_rsp *rsp;
450 		bool ret;
451 
452 		rsp = list_entry(queue->rsp_wr_wait_list.next,
453 				struct nvmet_rdma_rsp, wait_list);
454 		list_del(&rsp->wait_list);
455 
456 		spin_unlock(&queue->rsp_wr_wait_lock);
457 		ret = nvmet_rdma_execute_command(rsp);
458 		spin_lock(&queue->rsp_wr_wait_lock);
459 
460 		if (!ret) {
461 			list_add(&rsp->wait_list, &queue->rsp_wr_wait_list);
462 			break;
463 		}
464 	}
465 	spin_unlock(&queue->rsp_wr_wait_lock);
466 }
467 
468 
469 static void nvmet_rdma_release_rsp(struct nvmet_rdma_rsp *rsp)
470 {
471 	struct nvmet_rdma_queue *queue = rsp->queue;
472 
473 	atomic_add(1 + rsp->n_rdma, &queue->sq_wr_avail);
474 
475 	if (rsp->n_rdma) {
476 		rdma_rw_ctx_destroy(&rsp->rw, queue->cm_id->qp,
477 				queue->cm_id->port_num, rsp->req.sg,
478 				rsp->req.sg_cnt, nvmet_data_dir(&rsp->req));
479 	}
480 
481 	if (rsp->req.sg != &rsp->cmd->inline_sg)
482 		nvmet_rdma_free_sgl(rsp->req.sg, rsp->req.sg_cnt);
483 
484 	if (unlikely(!list_empty_careful(&queue->rsp_wr_wait_list)))
485 		nvmet_rdma_process_wr_wait_list(queue);
486 
487 	nvmet_rdma_put_rsp(rsp);
488 }
489 
490 static void nvmet_rdma_error_comp(struct nvmet_rdma_queue *queue)
491 {
492 	if (queue->nvme_sq.ctrl) {
493 		nvmet_ctrl_fatal_error(queue->nvme_sq.ctrl);
494 	} else {
495 		/*
496 		 * we didn't setup the controller yet in case
497 		 * of admin connect error, just disconnect and
498 		 * cleanup the queue
499 		 */
500 		nvmet_rdma_queue_disconnect(queue);
501 	}
502 }
503 
504 static void nvmet_rdma_send_done(struct ib_cq *cq, struct ib_wc *wc)
505 {
506 	struct nvmet_rdma_rsp *rsp =
507 		container_of(wc->wr_cqe, struct nvmet_rdma_rsp, send_cqe);
508 
509 	nvmet_rdma_release_rsp(rsp);
510 
511 	if (unlikely(wc->status != IB_WC_SUCCESS &&
512 		     wc->status != IB_WC_WR_FLUSH_ERR)) {
513 		pr_err("SEND for CQE 0x%p failed with status %s (%d).\n",
514 			wc->wr_cqe, ib_wc_status_msg(wc->status), wc->status);
515 		nvmet_rdma_error_comp(rsp->queue);
516 	}
517 }
518 
519 static void nvmet_rdma_queue_response(struct nvmet_req *req)
520 {
521 	struct nvmet_rdma_rsp *rsp =
522 		container_of(req, struct nvmet_rdma_rsp, req);
523 	struct rdma_cm_id *cm_id = rsp->queue->cm_id;
524 	struct ib_send_wr *first_wr, *bad_wr;
525 
526 	if (rsp->flags & NVMET_RDMA_REQ_INVALIDATE_RKEY) {
527 		rsp->send_wr.opcode = IB_WR_SEND_WITH_INV;
528 		rsp->send_wr.ex.invalidate_rkey = rsp->invalidate_rkey;
529 	} else {
530 		rsp->send_wr.opcode = IB_WR_SEND;
531 	}
532 
533 	if (nvmet_rdma_need_data_out(rsp))
534 		first_wr = rdma_rw_ctx_wrs(&rsp->rw, cm_id->qp,
535 				cm_id->port_num, NULL, &rsp->send_wr);
536 	else
537 		first_wr = &rsp->send_wr;
538 
539 	nvmet_rdma_post_recv(rsp->queue->dev, rsp->cmd);
540 	if (ib_post_send(cm_id->qp, first_wr, &bad_wr)) {
541 		pr_err("sending cmd response failed\n");
542 		nvmet_rdma_release_rsp(rsp);
543 	}
544 }
545 
546 static void nvmet_rdma_read_data_done(struct ib_cq *cq, struct ib_wc *wc)
547 {
548 	struct nvmet_rdma_rsp *rsp =
549 		container_of(wc->wr_cqe, struct nvmet_rdma_rsp, read_cqe);
550 	struct nvmet_rdma_queue *queue = cq->cq_context;
551 
552 	WARN_ON(rsp->n_rdma <= 0);
553 	atomic_add(rsp->n_rdma, &queue->sq_wr_avail);
554 	rdma_rw_ctx_destroy(&rsp->rw, queue->cm_id->qp,
555 			queue->cm_id->port_num, rsp->req.sg,
556 			rsp->req.sg_cnt, nvmet_data_dir(&rsp->req));
557 	rsp->n_rdma = 0;
558 
559 	if (unlikely(wc->status != IB_WC_SUCCESS)) {
560 		nvmet_rdma_release_rsp(rsp);
561 		if (wc->status != IB_WC_WR_FLUSH_ERR) {
562 			pr_info("RDMA READ for CQE 0x%p failed with status %s (%d).\n",
563 				wc->wr_cqe, ib_wc_status_msg(wc->status), wc->status);
564 			nvmet_rdma_error_comp(queue);
565 		}
566 		return;
567 	}
568 
569 	rsp->req.execute(&rsp->req);
570 }
571 
572 static void nvmet_rdma_use_inline_sg(struct nvmet_rdma_rsp *rsp, u32 len,
573 		u64 off)
574 {
575 	sg_init_table(&rsp->cmd->inline_sg, 1);
576 	sg_set_page(&rsp->cmd->inline_sg, rsp->cmd->inline_page, len, off);
577 	rsp->req.sg = &rsp->cmd->inline_sg;
578 	rsp->req.sg_cnt = 1;
579 }
580 
581 static u16 nvmet_rdma_map_sgl_inline(struct nvmet_rdma_rsp *rsp)
582 {
583 	struct nvme_sgl_desc *sgl = &rsp->req.cmd->common.dptr.sgl;
584 	u64 off = le64_to_cpu(sgl->addr);
585 	u32 len = le32_to_cpu(sgl->length);
586 
587 	if (!nvme_is_write(rsp->req.cmd))
588 		return NVME_SC_INVALID_FIELD | NVME_SC_DNR;
589 
590 	if (off + len > NVMET_RDMA_INLINE_DATA_SIZE) {
591 		pr_err("invalid inline data offset!\n");
592 		return NVME_SC_SGL_INVALID_OFFSET | NVME_SC_DNR;
593 	}
594 
595 	/* no data command? */
596 	if (!len)
597 		return 0;
598 
599 	nvmet_rdma_use_inline_sg(rsp, len, off);
600 	rsp->flags |= NVMET_RDMA_REQ_INLINE_DATA;
601 	return 0;
602 }
603 
604 static u16 nvmet_rdma_map_sgl_keyed(struct nvmet_rdma_rsp *rsp,
605 		struct nvme_keyed_sgl_desc *sgl, bool invalidate)
606 {
607 	struct rdma_cm_id *cm_id = rsp->queue->cm_id;
608 	u64 addr = le64_to_cpu(sgl->addr);
609 	u32 len = get_unaligned_le24(sgl->length);
610 	u32 key = get_unaligned_le32(sgl->key);
611 	int ret;
612 	u16 status;
613 
614 	/* no data command? */
615 	if (!len)
616 		return 0;
617 
618 	/* use the already allocated data buffer if possible */
619 	if (len <= NVMET_RDMA_INLINE_DATA_SIZE && rsp->queue->host_qid) {
620 		nvmet_rdma_use_inline_sg(rsp, len, 0);
621 	} else {
622 		status = nvmet_rdma_alloc_sgl(&rsp->req.sg, &rsp->req.sg_cnt,
623 				len);
624 		if (status)
625 			return status;
626 	}
627 
628 	ret = rdma_rw_ctx_init(&rsp->rw, cm_id->qp, cm_id->port_num,
629 			rsp->req.sg, rsp->req.sg_cnt, 0, addr, key,
630 			nvmet_data_dir(&rsp->req));
631 	if (ret < 0)
632 		return NVME_SC_INTERNAL;
633 	rsp->n_rdma += ret;
634 
635 	if (invalidate) {
636 		rsp->invalidate_rkey = key;
637 		rsp->flags |= NVMET_RDMA_REQ_INVALIDATE_RKEY;
638 	}
639 
640 	return 0;
641 }
642 
643 static u16 nvmet_rdma_map_sgl(struct nvmet_rdma_rsp *rsp)
644 {
645 	struct nvme_keyed_sgl_desc *sgl = &rsp->req.cmd->common.dptr.ksgl;
646 
647 	switch (sgl->type >> 4) {
648 	case NVME_SGL_FMT_DATA_DESC:
649 		switch (sgl->type & 0xf) {
650 		case NVME_SGL_FMT_OFFSET:
651 			return nvmet_rdma_map_sgl_inline(rsp);
652 		default:
653 			pr_err("invalid SGL subtype: %#x\n", sgl->type);
654 			return NVME_SC_INVALID_FIELD | NVME_SC_DNR;
655 		}
656 	case NVME_KEY_SGL_FMT_DATA_DESC:
657 		switch (sgl->type & 0xf) {
658 		case NVME_SGL_FMT_ADDRESS | NVME_SGL_FMT_INVALIDATE:
659 			return nvmet_rdma_map_sgl_keyed(rsp, sgl, true);
660 		case NVME_SGL_FMT_ADDRESS:
661 			return nvmet_rdma_map_sgl_keyed(rsp, sgl, false);
662 		default:
663 			pr_err("invalid SGL subtype: %#x\n", sgl->type);
664 			return NVME_SC_INVALID_FIELD | NVME_SC_DNR;
665 		}
666 	default:
667 		pr_err("invalid SGL type: %#x\n", sgl->type);
668 		return NVME_SC_SGL_INVALID_TYPE | NVME_SC_DNR;
669 	}
670 }
671 
672 static bool nvmet_rdma_execute_command(struct nvmet_rdma_rsp *rsp)
673 {
674 	struct nvmet_rdma_queue *queue = rsp->queue;
675 
676 	if (unlikely(atomic_sub_return(1 + rsp->n_rdma,
677 			&queue->sq_wr_avail) < 0)) {
678 		pr_debug("IB send queue full (needed %d): queue %u cntlid %u\n",
679 				1 + rsp->n_rdma, queue->idx,
680 				queue->nvme_sq.ctrl->cntlid);
681 		atomic_add(1 + rsp->n_rdma, &queue->sq_wr_avail);
682 		return false;
683 	}
684 
685 	if (nvmet_rdma_need_data_in(rsp)) {
686 		if (rdma_rw_ctx_post(&rsp->rw, queue->cm_id->qp,
687 				queue->cm_id->port_num, &rsp->read_cqe, NULL))
688 			nvmet_req_complete(&rsp->req, NVME_SC_DATA_XFER_ERROR);
689 	} else {
690 		rsp->req.execute(&rsp->req);
691 	}
692 
693 	return true;
694 }
695 
696 static void nvmet_rdma_handle_command(struct nvmet_rdma_queue *queue,
697 		struct nvmet_rdma_rsp *cmd)
698 {
699 	u16 status;
700 
701 	cmd->queue = queue;
702 	cmd->n_rdma = 0;
703 	cmd->req.port = queue->port;
704 
705 	if (!nvmet_req_init(&cmd->req, &queue->nvme_cq,
706 			&queue->nvme_sq, &nvmet_rdma_ops))
707 		return;
708 
709 	status = nvmet_rdma_map_sgl(cmd);
710 	if (status)
711 		goto out_err;
712 
713 	if (unlikely(!nvmet_rdma_execute_command(cmd))) {
714 		spin_lock(&queue->rsp_wr_wait_lock);
715 		list_add_tail(&cmd->wait_list, &queue->rsp_wr_wait_list);
716 		spin_unlock(&queue->rsp_wr_wait_lock);
717 	}
718 
719 	return;
720 
721 out_err:
722 	nvmet_req_complete(&cmd->req, status);
723 }
724 
725 static void nvmet_rdma_recv_done(struct ib_cq *cq, struct ib_wc *wc)
726 {
727 	struct nvmet_rdma_cmd *cmd =
728 		container_of(wc->wr_cqe, struct nvmet_rdma_cmd, cqe);
729 	struct nvmet_rdma_queue *queue = cq->cq_context;
730 	struct nvmet_rdma_rsp *rsp;
731 
732 	if (unlikely(wc->status != IB_WC_SUCCESS)) {
733 		if (wc->status != IB_WC_WR_FLUSH_ERR) {
734 			pr_err("RECV for CQE 0x%p failed with status %s (%d)\n",
735 				wc->wr_cqe, ib_wc_status_msg(wc->status),
736 				wc->status);
737 			nvmet_rdma_error_comp(queue);
738 		}
739 		return;
740 	}
741 
742 	if (unlikely(wc->byte_len < sizeof(struct nvme_command))) {
743 		pr_err("Ctrl Fatal Error: capsule size less than 64 bytes\n");
744 		nvmet_rdma_error_comp(queue);
745 		return;
746 	}
747 
748 	cmd->queue = queue;
749 	rsp = nvmet_rdma_get_rsp(queue);
750 	rsp->cmd = cmd;
751 	rsp->flags = 0;
752 	rsp->req.cmd = cmd->nvme_cmd;
753 
754 	if (unlikely(queue->state != NVMET_RDMA_Q_LIVE)) {
755 		unsigned long flags;
756 
757 		spin_lock_irqsave(&queue->state_lock, flags);
758 		if (queue->state == NVMET_RDMA_Q_CONNECTING)
759 			list_add_tail(&rsp->wait_list, &queue->rsp_wait_list);
760 		else
761 			nvmet_rdma_put_rsp(rsp);
762 		spin_unlock_irqrestore(&queue->state_lock, flags);
763 		return;
764 	}
765 
766 	nvmet_rdma_handle_command(queue, rsp);
767 }
768 
769 static void nvmet_rdma_destroy_srq(struct nvmet_rdma_device *ndev)
770 {
771 	if (!ndev->srq)
772 		return;
773 
774 	nvmet_rdma_free_cmds(ndev, ndev->srq_cmds, ndev->srq_size, false);
775 	ib_destroy_srq(ndev->srq);
776 }
777 
778 static int nvmet_rdma_init_srq(struct nvmet_rdma_device *ndev)
779 {
780 	struct ib_srq_init_attr srq_attr = { NULL, };
781 	struct ib_srq *srq;
782 	size_t srq_size;
783 	int ret, i;
784 
785 	srq_size = 4095;	/* XXX: tune */
786 
787 	srq_attr.attr.max_wr = srq_size;
788 	srq_attr.attr.max_sge = 2;
789 	srq_attr.attr.srq_limit = 0;
790 	srq_attr.srq_type = IB_SRQT_BASIC;
791 	srq = ib_create_srq(ndev->pd, &srq_attr);
792 	if (IS_ERR(srq)) {
793 		/*
794 		 * If SRQs aren't supported we just go ahead and use normal
795 		 * non-shared receive queues.
796 		 */
797 		pr_info("SRQ requested but not supported.\n");
798 		return 0;
799 	}
800 
801 	ndev->srq_cmds = nvmet_rdma_alloc_cmds(ndev, srq_size, false);
802 	if (IS_ERR(ndev->srq_cmds)) {
803 		ret = PTR_ERR(ndev->srq_cmds);
804 		goto out_destroy_srq;
805 	}
806 
807 	ndev->srq = srq;
808 	ndev->srq_size = srq_size;
809 
810 	for (i = 0; i < srq_size; i++)
811 		nvmet_rdma_post_recv(ndev, &ndev->srq_cmds[i]);
812 
813 	return 0;
814 
815 out_destroy_srq:
816 	ib_destroy_srq(srq);
817 	return ret;
818 }
819 
820 static void nvmet_rdma_free_dev(struct kref *ref)
821 {
822 	struct nvmet_rdma_device *ndev =
823 		container_of(ref, struct nvmet_rdma_device, ref);
824 
825 	mutex_lock(&device_list_mutex);
826 	list_del(&ndev->entry);
827 	mutex_unlock(&device_list_mutex);
828 
829 	nvmet_rdma_destroy_srq(ndev);
830 	ib_dealloc_pd(ndev->pd);
831 
832 	kfree(ndev);
833 }
834 
835 static struct nvmet_rdma_device *
836 nvmet_rdma_find_get_device(struct rdma_cm_id *cm_id)
837 {
838 	struct nvmet_rdma_device *ndev;
839 	int ret;
840 
841 	mutex_lock(&device_list_mutex);
842 	list_for_each_entry(ndev, &device_list, entry) {
843 		if (ndev->device->node_guid == cm_id->device->node_guid &&
844 		    kref_get_unless_zero(&ndev->ref))
845 			goto out_unlock;
846 	}
847 
848 	ndev = kzalloc(sizeof(*ndev), GFP_KERNEL);
849 	if (!ndev)
850 		goto out_err;
851 
852 	ndev->device = cm_id->device;
853 	kref_init(&ndev->ref);
854 
855 	ndev->pd = ib_alloc_pd(ndev->device);
856 	if (IS_ERR(ndev->pd))
857 		goto out_free_dev;
858 
859 	if (nvmet_rdma_use_srq) {
860 		ret = nvmet_rdma_init_srq(ndev);
861 		if (ret)
862 			goto out_free_pd;
863 	}
864 
865 	list_add(&ndev->entry, &device_list);
866 out_unlock:
867 	mutex_unlock(&device_list_mutex);
868 	pr_debug("added %s.\n", ndev->device->name);
869 	return ndev;
870 
871 out_free_pd:
872 	ib_dealloc_pd(ndev->pd);
873 out_free_dev:
874 	kfree(ndev);
875 out_err:
876 	mutex_unlock(&device_list_mutex);
877 	return NULL;
878 }
879 
880 static int nvmet_rdma_create_queue_ib(struct nvmet_rdma_queue *queue)
881 {
882 	struct ib_qp_init_attr qp_attr;
883 	struct nvmet_rdma_device *ndev = queue->dev;
884 	int comp_vector, nr_cqe, ret, i;
885 
886 	/*
887 	 * Spread the io queues across completion vectors,
888 	 * but still keep all admin queues on vector 0.
889 	 */
890 	comp_vector = !queue->host_qid ? 0 :
891 		queue->idx % ndev->device->num_comp_vectors;
892 
893 	/*
894 	 * Reserve CQ slots for RECV + RDMA_READ/RDMA_WRITE + RDMA_SEND.
895 	 */
896 	nr_cqe = queue->recv_queue_size + 2 * queue->send_queue_size;
897 
898 	queue->cq = ib_alloc_cq(ndev->device, queue,
899 			nr_cqe + 1, comp_vector,
900 			IB_POLL_WORKQUEUE);
901 	if (IS_ERR(queue->cq)) {
902 		ret = PTR_ERR(queue->cq);
903 		pr_err("failed to create CQ cqe= %d ret= %d\n",
904 		       nr_cqe + 1, ret);
905 		goto out;
906 	}
907 
908 	memset(&qp_attr, 0, sizeof(qp_attr));
909 	qp_attr.qp_context = queue;
910 	qp_attr.event_handler = nvmet_rdma_qp_event;
911 	qp_attr.send_cq = queue->cq;
912 	qp_attr.recv_cq = queue->cq;
913 	qp_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
914 	qp_attr.qp_type = IB_QPT_RC;
915 	/* +1 for drain */
916 	qp_attr.cap.max_send_wr = queue->send_queue_size + 1;
917 	qp_attr.cap.max_rdma_ctxs = queue->send_queue_size;
918 	qp_attr.cap.max_send_sge = max(ndev->device->attrs.max_sge_rd,
919 					ndev->device->attrs.max_sge);
920 
921 	if (ndev->srq) {
922 		qp_attr.srq = ndev->srq;
923 	} else {
924 		/* +1 for drain */
925 		qp_attr.cap.max_recv_wr = 1 + queue->recv_queue_size;
926 		qp_attr.cap.max_recv_sge = 2;
927 	}
928 
929 	ret = rdma_create_qp(queue->cm_id, ndev->pd, &qp_attr);
930 	if (ret) {
931 		pr_err("failed to create_qp ret= %d\n", ret);
932 		goto err_destroy_cq;
933 	}
934 
935 	atomic_set(&queue->sq_wr_avail, qp_attr.cap.max_send_wr);
936 
937 	pr_debug("%s: max_cqe= %d max_sge= %d sq_size = %d cm_id= %p\n",
938 		 __func__, queue->cq->cqe, qp_attr.cap.max_send_sge,
939 		 qp_attr.cap.max_send_wr, queue->cm_id);
940 
941 	if (!ndev->srq) {
942 		for (i = 0; i < queue->recv_queue_size; i++) {
943 			queue->cmds[i].queue = queue;
944 			nvmet_rdma_post_recv(ndev, &queue->cmds[i]);
945 		}
946 	}
947 
948 out:
949 	return ret;
950 
951 err_destroy_cq:
952 	ib_free_cq(queue->cq);
953 	goto out;
954 }
955 
956 static void nvmet_rdma_destroy_queue_ib(struct nvmet_rdma_queue *queue)
957 {
958 	rdma_destroy_qp(queue->cm_id);
959 	ib_free_cq(queue->cq);
960 }
961 
962 static void nvmet_rdma_free_queue(struct nvmet_rdma_queue *queue)
963 {
964 	pr_info("freeing queue %d\n", queue->idx);
965 
966 	nvmet_sq_destroy(&queue->nvme_sq);
967 
968 	nvmet_rdma_destroy_queue_ib(queue);
969 	if (!queue->dev->srq) {
970 		nvmet_rdma_free_cmds(queue->dev, queue->cmds,
971 				queue->recv_queue_size,
972 				!queue->host_qid);
973 	}
974 	nvmet_rdma_free_rsps(queue);
975 	ida_simple_remove(&nvmet_rdma_queue_ida, queue->idx);
976 	kfree(queue);
977 }
978 
979 static void nvmet_rdma_release_queue_work(struct work_struct *w)
980 {
981 	struct nvmet_rdma_queue *queue =
982 		container_of(w, struct nvmet_rdma_queue, release_work);
983 	struct rdma_cm_id *cm_id = queue->cm_id;
984 	struct nvmet_rdma_device *dev = queue->dev;
985 
986 	nvmet_rdma_free_queue(queue);
987 	rdma_destroy_id(cm_id);
988 	kref_put(&dev->ref, nvmet_rdma_free_dev);
989 }
990 
991 static int
992 nvmet_rdma_parse_cm_connect_req(struct rdma_conn_param *conn,
993 				struct nvmet_rdma_queue *queue)
994 {
995 	struct nvme_rdma_cm_req *req;
996 
997 	req = (struct nvme_rdma_cm_req *)conn->private_data;
998 	if (!req || conn->private_data_len == 0)
999 		return NVME_RDMA_CM_INVALID_LEN;
1000 
1001 	if (le16_to_cpu(req->recfmt) != NVME_RDMA_CM_FMT_1_0)
1002 		return NVME_RDMA_CM_INVALID_RECFMT;
1003 
1004 	queue->host_qid = le16_to_cpu(req->qid);
1005 
1006 	/*
1007 	 * req->hsqsize corresponds to our recv queue size
1008 	 * req->hrqsize corresponds to our send queue size
1009 	 */
1010 	queue->recv_queue_size = le16_to_cpu(req->hsqsize);
1011 	queue->send_queue_size = le16_to_cpu(req->hrqsize);
1012 
1013 	if (!queue->host_qid && queue->recv_queue_size > NVMF_AQ_DEPTH)
1014 		return NVME_RDMA_CM_INVALID_HSQSIZE;
1015 
1016 	/* XXX: Should we enforce some kind of max for IO queues? */
1017 
1018 	return 0;
1019 }
1020 
1021 static int nvmet_rdma_cm_reject(struct rdma_cm_id *cm_id,
1022 				enum nvme_rdma_cm_status status)
1023 {
1024 	struct nvme_rdma_cm_rej rej;
1025 
1026 	rej.recfmt = cpu_to_le16(NVME_RDMA_CM_FMT_1_0);
1027 	rej.sts = cpu_to_le16(status);
1028 
1029 	return rdma_reject(cm_id, (void *)&rej, sizeof(rej));
1030 }
1031 
1032 static struct nvmet_rdma_queue *
1033 nvmet_rdma_alloc_queue(struct nvmet_rdma_device *ndev,
1034 		struct rdma_cm_id *cm_id,
1035 		struct rdma_cm_event *event)
1036 {
1037 	struct nvmet_rdma_queue *queue;
1038 	int ret;
1039 
1040 	queue = kzalloc(sizeof(*queue), GFP_KERNEL);
1041 	if (!queue) {
1042 		ret = NVME_RDMA_CM_NO_RSC;
1043 		goto out_reject;
1044 	}
1045 
1046 	ret = nvmet_sq_init(&queue->nvme_sq);
1047 	if (ret)
1048 		goto out_free_queue;
1049 
1050 	ret = nvmet_rdma_parse_cm_connect_req(&event->param.conn, queue);
1051 	if (ret)
1052 		goto out_destroy_sq;
1053 
1054 	/*
1055 	 * Schedules the actual release because calling rdma_destroy_id from
1056 	 * inside a CM callback would trigger a deadlock. (great API design..)
1057 	 */
1058 	INIT_WORK(&queue->release_work, nvmet_rdma_release_queue_work);
1059 	queue->dev = ndev;
1060 	queue->cm_id = cm_id;
1061 
1062 	spin_lock_init(&queue->state_lock);
1063 	queue->state = NVMET_RDMA_Q_CONNECTING;
1064 	INIT_LIST_HEAD(&queue->rsp_wait_list);
1065 	INIT_LIST_HEAD(&queue->rsp_wr_wait_list);
1066 	spin_lock_init(&queue->rsp_wr_wait_lock);
1067 	INIT_LIST_HEAD(&queue->free_rsps);
1068 	spin_lock_init(&queue->rsps_lock);
1069 
1070 	queue->idx = ida_simple_get(&nvmet_rdma_queue_ida, 0, 0, GFP_KERNEL);
1071 	if (queue->idx < 0) {
1072 		ret = NVME_RDMA_CM_NO_RSC;
1073 		goto out_free_queue;
1074 	}
1075 
1076 	ret = nvmet_rdma_alloc_rsps(queue);
1077 	if (ret) {
1078 		ret = NVME_RDMA_CM_NO_RSC;
1079 		goto out_ida_remove;
1080 	}
1081 
1082 	if (!ndev->srq) {
1083 		queue->cmds = nvmet_rdma_alloc_cmds(ndev,
1084 				queue->recv_queue_size,
1085 				!queue->host_qid);
1086 		if (IS_ERR(queue->cmds)) {
1087 			ret = NVME_RDMA_CM_NO_RSC;
1088 			goto out_free_responses;
1089 		}
1090 	}
1091 
1092 	ret = nvmet_rdma_create_queue_ib(queue);
1093 	if (ret) {
1094 		pr_err("%s: creating RDMA queue failed (%d).\n",
1095 			__func__, ret);
1096 		ret = NVME_RDMA_CM_NO_RSC;
1097 		goto out_free_cmds;
1098 	}
1099 
1100 	return queue;
1101 
1102 out_free_cmds:
1103 	if (!ndev->srq) {
1104 		nvmet_rdma_free_cmds(queue->dev, queue->cmds,
1105 				queue->recv_queue_size,
1106 				!queue->host_qid);
1107 	}
1108 out_free_responses:
1109 	nvmet_rdma_free_rsps(queue);
1110 out_ida_remove:
1111 	ida_simple_remove(&nvmet_rdma_queue_ida, queue->idx);
1112 out_destroy_sq:
1113 	nvmet_sq_destroy(&queue->nvme_sq);
1114 out_free_queue:
1115 	kfree(queue);
1116 out_reject:
1117 	nvmet_rdma_cm_reject(cm_id, ret);
1118 	return NULL;
1119 }
1120 
1121 static void nvmet_rdma_qp_event(struct ib_event *event, void *priv)
1122 {
1123 	struct nvmet_rdma_queue *queue = priv;
1124 
1125 	switch (event->event) {
1126 	case IB_EVENT_COMM_EST:
1127 		rdma_notify(queue->cm_id, event->event);
1128 		break;
1129 	default:
1130 		pr_err("received unrecognized IB QP event %d\n", event->event);
1131 		break;
1132 	}
1133 }
1134 
1135 static int nvmet_rdma_cm_accept(struct rdma_cm_id *cm_id,
1136 		struct nvmet_rdma_queue *queue,
1137 		struct rdma_conn_param *p)
1138 {
1139 	struct rdma_conn_param  param = { };
1140 	struct nvme_rdma_cm_rep priv = { };
1141 	int ret = -ENOMEM;
1142 
1143 	param.rnr_retry_count = 7;
1144 	param.flow_control = 1;
1145 	param.initiator_depth = min_t(u8, p->initiator_depth,
1146 		queue->dev->device->attrs.max_qp_init_rd_atom);
1147 	param.private_data = &priv;
1148 	param.private_data_len = sizeof(priv);
1149 	priv.recfmt = cpu_to_le16(NVME_RDMA_CM_FMT_1_0);
1150 	priv.crqsize = cpu_to_le16(queue->recv_queue_size);
1151 
1152 	ret = rdma_accept(cm_id, &param);
1153 	if (ret)
1154 		pr_err("rdma_accept failed (error code = %d)\n", ret);
1155 
1156 	return ret;
1157 }
1158 
1159 static int nvmet_rdma_queue_connect(struct rdma_cm_id *cm_id,
1160 		struct rdma_cm_event *event)
1161 {
1162 	struct nvmet_rdma_device *ndev;
1163 	struct nvmet_rdma_queue *queue;
1164 	int ret = -EINVAL;
1165 
1166 	ndev = nvmet_rdma_find_get_device(cm_id);
1167 	if (!ndev) {
1168 		pr_err("no client data!\n");
1169 		nvmet_rdma_cm_reject(cm_id, NVME_RDMA_CM_NO_RSC);
1170 		return -ECONNREFUSED;
1171 	}
1172 
1173 	queue = nvmet_rdma_alloc_queue(ndev, cm_id, event);
1174 	if (!queue) {
1175 		ret = -ENOMEM;
1176 		goto put_device;
1177 	}
1178 	queue->port = cm_id->context;
1179 
1180 	ret = nvmet_rdma_cm_accept(cm_id, queue, &event->param.conn);
1181 	if (ret)
1182 		goto release_queue;
1183 
1184 	mutex_lock(&nvmet_rdma_queue_mutex);
1185 	list_add_tail(&queue->queue_list, &nvmet_rdma_queue_list);
1186 	mutex_unlock(&nvmet_rdma_queue_mutex);
1187 
1188 	return 0;
1189 
1190 release_queue:
1191 	nvmet_rdma_free_queue(queue);
1192 put_device:
1193 	kref_put(&ndev->ref, nvmet_rdma_free_dev);
1194 
1195 	return ret;
1196 }
1197 
1198 static void nvmet_rdma_queue_established(struct nvmet_rdma_queue *queue)
1199 {
1200 	unsigned long flags;
1201 
1202 	spin_lock_irqsave(&queue->state_lock, flags);
1203 	if (queue->state != NVMET_RDMA_Q_CONNECTING) {
1204 		pr_warn("trying to establish a connected queue\n");
1205 		goto out_unlock;
1206 	}
1207 	queue->state = NVMET_RDMA_Q_LIVE;
1208 
1209 	while (!list_empty(&queue->rsp_wait_list)) {
1210 		struct nvmet_rdma_rsp *cmd;
1211 
1212 		cmd = list_first_entry(&queue->rsp_wait_list,
1213 					struct nvmet_rdma_rsp, wait_list);
1214 		list_del(&cmd->wait_list);
1215 
1216 		spin_unlock_irqrestore(&queue->state_lock, flags);
1217 		nvmet_rdma_handle_command(queue, cmd);
1218 		spin_lock_irqsave(&queue->state_lock, flags);
1219 	}
1220 
1221 out_unlock:
1222 	spin_unlock_irqrestore(&queue->state_lock, flags);
1223 }
1224 
1225 static void __nvmet_rdma_queue_disconnect(struct nvmet_rdma_queue *queue)
1226 {
1227 	bool disconnect = false;
1228 	unsigned long flags;
1229 
1230 	pr_debug("cm_id= %p queue->state= %d\n", queue->cm_id, queue->state);
1231 
1232 	spin_lock_irqsave(&queue->state_lock, flags);
1233 	switch (queue->state) {
1234 	case NVMET_RDMA_Q_CONNECTING:
1235 	case NVMET_RDMA_Q_LIVE:
1236 		disconnect = true;
1237 		queue->state = NVMET_RDMA_Q_DISCONNECTING;
1238 		break;
1239 	case NVMET_RDMA_Q_DISCONNECTING:
1240 		break;
1241 	}
1242 	spin_unlock_irqrestore(&queue->state_lock, flags);
1243 
1244 	if (disconnect) {
1245 		rdma_disconnect(queue->cm_id);
1246 		ib_drain_qp(queue->cm_id->qp);
1247 		schedule_work(&queue->release_work);
1248 	}
1249 }
1250 
1251 static void nvmet_rdma_queue_disconnect(struct nvmet_rdma_queue *queue)
1252 {
1253 	bool disconnect = false;
1254 
1255 	mutex_lock(&nvmet_rdma_queue_mutex);
1256 	if (!list_empty(&queue->queue_list)) {
1257 		list_del_init(&queue->queue_list);
1258 		disconnect = true;
1259 	}
1260 	mutex_unlock(&nvmet_rdma_queue_mutex);
1261 
1262 	if (disconnect)
1263 		__nvmet_rdma_queue_disconnect(queue);
1264 }
1265 
1266 static void nvmet_rdma_queue_connect_fail(struct rdma_cm_id *cm_id,
1267 		struct nvmet_rdma_queue *queue)
1268 {
1269 	WARN_ON_ONCE(queue->state != NVMET_RDMA_Q_CONNECTING);
1270 
1271 	pr_err("failed to connect queue\n");
1272 	schedule_work(&queue->release_work);
1273 }
1274 
1275 static int nvmet_rdma_cm_handler(struct rdma_cm_id *cm_id,
1276 		struct rdma_cm_event *event)
1277 {
1278 	struct nvmet_rdma_queue *queue = NULL;
1279 	int ret = 0;
1280 
1281 	if (cm_id->qp)
1282 		queue = cm_id->qp->qp_context;
1283 
1284 	pr_debug("%s (%d): status %d id %p\n",
1285 		rdma_event_msg(event->event), event->event,
1286 		event->status, cm_id);
1287 
1288 	switch (event->event) {
1289 	case RDMA_CM_EVENT_CONNECT_REQUEST:
1290 		ret = nvmet_rdma_queue_connect(cm_id, event);
1291 		break;
1292 	case RDMA_CM_EVENT_ESTABLISHED:
1293 		nvmet_rdma_queue_established(queue);
1294 		break;
1295 	case RDMA_CM_EVENT_ADDR_CHANGE:
1296 	case RDMA_CM_EVENT_DISCONNECTED:
1297 	case RDMA_CM_EVENT_DEVICE_REMOVAL:
1298 	case RDMA_CM_EVENT_TIMEWAIT_EXIT:
1299 		/*
1300 		 * We can get the device removal callback even for a
1301 		 * CM ID that we aren't actually using.  In that case
1302 		 * the context pointer is NULL, so we shouldn't try
1303 		 * to disconnect a non-existing queue.  But we also
1304 		 * need to return 1 so that the core will destroy
1305 		 * it's own ID.  What a great API design..
1306 		 */
1307 		if (queue)
1308 			nvmet_rdma_queue_disconnect(queue);
1309 		else
1310 			ret = 1;
1311 		break;
1312 	case RDMA_CM_EVENT_REJECTED:
1313 	case RDMA_CM_EVENT_UNREACHABLE:
1314 	case RDMA_CM_EVENT_CONNECT_ERROR:
1315 		nvmet_rdma_queue_connect_fail(cm_id, queue);
1316 		break;
1317 	default:
1318 		pr_err("received unrecognized RDMA CM event %d\n",
1319 			event->event);
1320 		break;
1321 	}
1322 
1323 	return ret;
1324 }
1325 
1326 static void nvmet_rdma_delete_ctrl(struct nvmet_ctrl *ctrl)
1327 {
1328 	struct nvmet_rdma_queue *queue;
1329 
1330 restart:
1331 	mutex_lock(&nvmet_rdma_queue_mutex);
1332 	list_for_each_entry(queue, &nvmet_rdma_queue_list, queue_list) {
1333 		if (queue->nvme_sq.ctrl == ctrl) {
1334 			list_del_init(&queue->queue_list);
1335 			mutex_unlock(&nvmet_rdma_queue_mutex);
1336 
1337 			__nvmet_rdma_queue_disconnect(queue);
1338 			goto restart;
1339 		}
1340 	}
1341 	mutex_unlock(&nvmet_rdma_queue_mutex);
1342 }
1343 
1344 static int nvmet_rdma_add_port(struct nvmet_port *port)
1345 {
1346 	struct rdma_cm_id *cm_id;
1347 	struct sockaddr_in addr_in;
1348 	u16 port_in;
1349 	int ret;
1350 
1351 	switch (port->disc_addr.adrfam) {
1352 	case NVMF_ADDR_FAMILY_IP4:
1353 		break;
1354 	default:
1355 		pr_err("address family %d not supported\n",
1356 				port->disc_addr.adrfam);
1357 		return -EINVAL;
1358 	}
1359 
1360 	ret = kstrtou16(port->disc_addr.trsvcid, 0, &port_in);
1361 	if (ret)
1362 		return ret;
1363 
1364 	addr_in.sin_family = AF_INET;
1365 	addr_in.sin_addr.s_addr = in_aton(port->disc_addr.traddr);
1366 	addr_in.sin_port = htons(port_in);
1367 
1368 	cm_id = rdma_create_id(&init_net, nvmet_rdma_cm_handler, port,
1369 			RDMA_PS_TCP, IB_QPT_RC);
1370 	if (IS_ERR(cm_id)) {
1371 		pr_err("CM ID creation failed\n");
1372 		return PTR_ERR(cm_id);
1373 	}
1374 
1375 	ret = rdma_bind_addr(cm_id, (struct sockaddr *)&addr_in);
1376 	if (ret) {
1377 		pr_err("binding CM ID to %pISpc failed (%d)\n", &addr_in, ret);
1378 		goto out_destroy_id;
1379 	}
1380 
1381 	ret = rdma_listen(cm_id, 128);
1382 	if (ret) {
1383 		pr_err("listening to %pISpc failed (%d)\n", &addr_in, ret);
1384 		goto out_destroy_id;
1385 	}
1386 
1387 	pr_info("enabling port %d (%pISpc)\n",
1388 		le16_to_cpu(port->disc_addr.portid), &addr_in);
1389 	port->priv = cm_id;
1390 	return 0;
1391 
1392 out_destroy_id:
1393 	rdma_destroy_id(cm_id);
1394 	return ret;
1395 }
1396 
1397 static void nvmet_rdma_remove_port(struct nvmet_port *port)
1398 {
1399 	struct rdma_cm_id *cm_id = port->priv;
1400 
1401 	rdma_destroy_id(cm_id);
1402 }
1403 
1404 static struct nvmet_fabrics_ops nvmet_rdma_ops = {
1405 	.owner			= THIS_MODULE,
1406 	.type			= NVMF_TRTYPE_RDMA,
1407 	.sqe_inline_size	= NVMET_RDMA_INLINE_DATA_SIZE,
1408 	.msdbd			= 1,
1409 	.has_keyed_sgls		= 1,
1410 	.add_port		= nvmet_rdma_add_port,
1411 	.remove_port		= nvmet_rdma_remove_port,
1412 	.queue_response		= nvmet_rdma_queue_response,
1413 	.delete_ctrl		= nvmet_rdma_delete_ctrl,
1414 };
1415 
1416 static int __init nvmet_rdma_init(void)
1417 {
1418 	return nvmet_register_transport(&nvmet_rdma_ops);
1419 }
1420 
1421 static void __exit nvmet_rdma_exit(void)
1422 {
1423 	struct nvmet_rdma_queue *queue;
1424 
1425 	nvmet_unregister_transport(&nvmet_rdma_ops);
1426 
1427 	flush_scheduled_work();
1428 
1429 	mutex_lock(&nvmet_rdma_queue_mutex);
1430 	while ((queue = list_first_entry_or_null(&nvmet_rdma_queue_list,
1431 			struct nvmet_rdma_queue, queue_list))) {
1432 		list_del_init(&queue->queue_list);
1433 
1434 		mutex_unlock(&nvmet_rdma_queue_mutex);
1435 		__nvmet_rdma_queue_disconnect(queue);
1436 		mutex_lock(&nvmet_rdma_queue_mutex);
1437 	}
1438 	mutex_unlock(&nvmet_rdma_queue_mutex);
1439 
1440 	flush_scheduled_work();
1441 	ida_destroy(&nvmet_rdma_queue_ida);
1442 }
1443 
1444 module_init(nvmet_rdma_init);
1445 module_exit(nvmet_rdma_exit);
1446 
1447 MODULE_LICENSE("GPL v2");
1448 MODULE_ALIAS("nvmet-transport-1"); /* 1 == NVMF_TRTYPE_RDMA */
1449