xref: /openbmc/linux/drivers/nvme/target/rdma.c (revision 232b0b08)
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 	NVMET_RDMA_IN_DEVICE_REMOVAL,
81 };
82 
83 struct nvmet_rdma_queue {
84 	struct rdma_cm_id	*cm_id;
85 	struct nvmet_port	*port;
86 	struct ib_cq		*cq;
87 	atomic_t		sq_wr_avail;
88 	struct nvmet_rdma_device *dev;
89 	spinlock_t		state_lock;
90 	enum nvmet_rdma_queue_state state;
91 	struct nvmet_cq		nvme_cq;
92 	struct nvmet_sq		nvme_sq;
93 
94 	struct nvmet_rdma_rsp	*rsps;
95 	struct list_head	free_rsps;
96 	spinlock_t		rsps_lock;
97 	struct nvmet_rdma_cmd	*cmds;
98 
99 	struct work_struct	release_work;
100 	struct list_head	rsp_wait_list;
101 	struct list_head	rsp_wr_wait_list;
102 	spinlock_t		rsp_wr_wait_lock;
103 
104 	int			idx;
105 	int			host_qid;
106 	int			recv_queue_size;
107 	int			send_queue_size;
108 
109 	struct list_head	queue_list;
110 };
111 
112 struct nvmet_rdma_device {
113 	struct ib_device	*device;
114 	struct ib_pd		*pd;
115 	struct ib_srq		*srq;
116 	struct nvmet_rdma_cmd	*srq_cmds;
117 	size_t			srq_size;
118 	struct kref		ref;
119 	struct list_head	entry;
120 };
121 
122 static bool nvmet_rdma_use_srq;
123 module_param_named(use_srq, nvmet_rdma_use_srq, bool, 0444);
124 MODULE_PARM_DESC(use_srq, "Use shared receive queue.");
125 
126 static DEFINE_IDA(nvmet_rdma_queue_ida);
127 static LIST_HEAD(nvmet_rdma_queue_list);
128 static DEFINE_MUTEX(nvmet_rdma_queue_mutex);
129 
130 static LIST_HEAD(device_list);
131 static DEFINE_MUTEX(device_list_mutex);
132 
133 static bool nvmet_rdma_execute_command(struct nvmet_rdma_rsp *rsp);
134 static void nvmet_rdma_send_done(struct ib_cq *cq, struct ib_wc *wc);
135 static void nvmet_rdma_recv_done(struct ib_cq *cq, struct ib_wc *wc);
136 static void nvmet_rdma_read_data_done(struct ib_cq *cq, struct ib_wc *wc);
137 static void nvmet_rdma_qp_event(struct ib_event *event, void *priv);
138 static void nvmet_rdma_queue_disconnect(struct nvmet_rdma_queue *queue);
139 
140 static struct nvmet_fabrics_ops nvmet_rdma_ops;
141 
142 /* XXX: really should move to a generic header sooner or later.. */
143 static inline u32 get_unaligned_le24(const u8 *p)
144 {
145 	return (u32)p[0] | (u32)p[1] << 8 | (u32)p[2] << 16;
146 }
147 
148 static inline bool nvmet_rdma_need_data_in(struct nvmet_rdma_rsp *rsp)
149 {
150 	return nvme_is_write(rsp->req.cmd) &&
151 		rsp->req.data_len &&
152 		!(rsp->flags & NVMET_RDMA_REQ_INLINE_DATA);
153 }
154 
155 static inline bool nvmet_rdma_need_data_out(struct nvmet_rdma_rsp *rsp)
156 {
157 	return !nvme_is_write(rsp->req.cmd) &&
158 		rsp->req.data_len &&
159 		!rsp->req.rsp->status &&
160 		!(rsp->flags & NVMET_RDMA_REQ_INLINE_DATA);
161 }
162 
163 static inline struct nvmet_rdma_rsp *
164 nvmet_rdma_get_rsp(struct nvmet_rdma_queue *queue)
165 {
166 	struct nvmet_rdma_rsp *rsp;
167 	unsigned long flags;
168 
169 	spin_lock_irqsave(&queue->rsps_lock, flags);
170 	rsp = list_first_entry(&queue->free_rsps,
171 				struct nvmet_rdma_rsp, free_list);
172 	list_del(&rsp->free_list);
173 	spin_unlock_irqrestore(&queue->rsps_lock, flags);
174 
175 	return rsp;
176 }
177 
178 static inline void
179 nvmet_rdma_put_rsp(struct nvmet_rdma_rsp *rsp)
180 {
181 	unsigned long flags;
182 
183 	spin_lock_irqsave(&rsp->queue->rsps_lock, flags);
184 	list_add_tail(&rsp->free_list, &rsp->queue->free_rsps);
185 	spin_unlock_irqrestore(&rsp->queue->rsps_lock, flags);
186 }
187 
188 static void nvmet_rdma_free_sgl(struct scatterlist *sgl, unsigned int nents)
189 {
190 	struct scatterlist *sg;
191 	int count;
192 
193 	if (!sgl || !nents)
194 		return;
195 
196 	for_each_sg(sgl, sg, nents, count)
197 		__free_page(sg_page(sg));
198 	kfree(sgl);
199 }
200 
201 static int nvmet_rdma_alloc_sgl(struct scatterlist **sgl, unsigned int *nents,
202 		u32 length)
203 {
204 	struct scatterlist *sg;
205 	struct page *page;
206 	unsigned int nent;
207 	int i = 0;
208 
209 	nent = DIV_ROUND_UP(length, PAGE_SIZE);
210 	sg = kmalloc_array(nent, sizeof(struct scatterlist), GFP_KERNEL);
211 	if (!sg)
212 		goto out;
213 
214 	sg_init_table(sg, nent);
215 
216 	while (length) {
217 		u32 page_len = min_t(u32, length, PAGE_SIZE);
218 
219 		page = alloc_page(GFP_KERNEL);
220 		if (!page)
221 			goto out_free_pages;
222 
223 		sg_set_page(&sg[i], page, page_len, 0);
224 		length -= page_len;
225 		i++;
226 	}
227 	*sgl = sg;
228 	*nents = nent;
229 	return 0;
230 
231 out_free_pages:
232 	while (i > 0) {
233 		i--;
234 		__free_page(sg_page(&sg[i]));
235 	}
236 	kfree(sg);
237 out:
238 	return NVME_SC_INTERNAL;
239 }
240 
241 static int nvmet_rdma_alloc_cmd(struct nvmet_rdma_device *ndev,
242 			struct nvmet_rdma_cmd *c, bool admin)
243 {
244 	/* NVMe command / RDMA RECV */
245 	c->nvme_cmd = kmalloc(sizeof(*c->nvme_cmd), GFP_KERNEL);
246 	if (!c->nvme_cmd)
247 		goto out;
248 
249 	c->sge[0].addr = ib_dma_map_single(ndev->device, c->nvme_cmd,
250 			sizeof(*c->nvme_cmd), DMA_FROM_DEVICE);
251 	if (ib_dma_mapping_error(ndev->device, c->sge[0].addr))
252 		goto out_free_cmd;
253 
254 	c->sge[0].length = sizeof(*c->nvme_cmd);
255 	c->sge[0].lkey = ndev->pd->local_dma_lkey;
256 
257 	if (!admin) {
258 		c->inline_page = alloc_pages(GFP_KERNEL,
259 				get_order(NVMET_RDMA_INLINE_DATA_SIZE));
260 		if (!c->inline_page)
261 			goto out_unmap_cmd;
262 		c->sge[1].addr = ib_dma_map_page(ndev->device,
263 				c->inline_page, 0, NVMET_RDMA_INLINE_DATA_SIZE,
264 				DMA_FROM_DEVICE);
265 		if (ib_dma_mapping_error(ndev->device, c->sge[1].addr))
266 			goto out_free_inline_page;
267 		c->sge[1].length = NVMET_RDMA_INLINE_DATA_SIZE;
268 		c->sge[1].lkey = ndev->pd->local_dma_lkey;
269 	}
270 
271 	c->cqe.done = nvmet_rdma_recv_done;
272 
273 	c->wr.wr_cqe = &c->cqe;
274 	c->wr.sg_list = c->sge;
275 	c->wr.num_sge = admin ? 1 : 2;
276 
277 	return 0;
278 
279 out_free_inline_page:
280 	if (!admin) {
281 		__free_pages(c->inline_page,
282 				get_order(NVMET_RDMA_INLINE_DATA_SIZE));
283 	}
284 out_unmap_cmd:
285 	ib_dma_unmap_single(ndev->device, c->sge[0].addr,
286 			sizeof(*c->nvme_cmd), DMA_FROM_DEVICE);
287 out_free_cmd:
288 	kfree(c->nvme_cmd);
289 
290 out:
291 	return -ENOMEM;
292 }
293 
294 static void nvmet_rdma_free_cmd(struct nvmet_rdma_device *ndev,
295 		struct nvmet_rdma_cmd *c, bool admin)
296 {
297 	if (!admin) {
298 		ib_dma_unmap_page(ndev->device, c->sge[1].addr,
299 				NVMET_RDMA_INLINE_DATA_SIZE, DMA_FROM_DEVICE);
300 		__free_pages(c->inline_page,
301 				get_order(NVMET_RDMA_INLINE_DATA_SIZE));
302 	}
303 	ib_dma_unmap_single(ndev->device, c->sge[0].addr,
304 				sizeof(*c->nvme_cmd), DMA_FROM_DEVICE);
305 	kfree(c->nvme_cmd);
306 }
307 
308 static struct nvmet_rdma_cmd *
309 nvmet_rdma_alloc_cmds(struct nvmet_rdma_device *ndev,
310 		int nr_cmds, bool admin)
311 {
312 	struct nvmet_rdma_cmd *cmds;
313 	int ret = -EINVAL, i;
314 
315 	cmds = kcalloc(nr_cmds, sizeof(struct nvmet_rdma_cmd), GFP_KERNEL);
316 	if (!cmds)
317 		goto out;
318 
319 	for (i = 0; i < nr_cmds; i++) {
320 		ret = nvmet_rdma_alloc_cmd(ndev, cmds + i, admin);
321 		if (ret)
322 			goto out_free;
323 	}
324 
325 	return cmds;
326 
327 out_free:
328 	while (--i >= 0)
329 		nvmet_rdma_free_cmd(ndev, cmds + i, admin);
330 	kfree(cmds);
331 out:
332 	return ERR_PTR(ret);
333 }
334 
335 static void nvmet_rdma_free_cmds(struct nvmet_rdma_device *ndev,
336 		struct nvmet_rdma_cmd *cmds, int nr_cmds, bool admin)
337 {
338 	int i;
339 
340 	for (i = 0; i < nr_cmds; i++)
341 		nvmet_rdma_free_cmd(ndev, cmds + i, admin);
342 	kfree(cmds);
343 }
344 
345 static int nvmet_rdma_alloc_rsp(struct nvmet_rdma_device *ndev,
346 		struct nvmet_rdma_rsp *r)
347 {
348 	/* NVMe CQE / RDMA SEND */
349 	r->req.rsp = kmalloc(sizeof(*r->req.rsp), GFP_KERNEL);
350 	if (!r->req.rsp)
351 		goto out;
352 
353 	r->send_sge.addr = ib_dma_map_single(ndev->device, r->req.rsp,
354 			sizeof(*r->req.rsp), DMA_TO_DEVICE);
355 	if (ib_dma_mapping_error(ndev->device, r->send_sge.addr))
356 		goto out_free_rsp;
357 
358 	r->send_sge.length = sizeof(*r->req.rsp);
359 	r->send_sge.lkey = ndev->pd->local_dma_lkey;
360 
361 	r->send_cqe.done = nvmet_rdma_send_done;
362 
363 	r->send_wr.wr_cqe = &r->send_cqe;
364 	r->send_wr.sg_list = &r->send_sge;
365 	r->send_wr.num_sge = 1;
366 	r->send_wr.send_flags = IB_SEND_SIGNALED;
367 
368 	/* Data In / RDMA READ */
369 	r->read_cqe.done = nvmet_rdma_read_data_done;
370 	return 0;
371 
372 out_free_rsp:
373 	kfree(r->req.rsp);
374 out:
375 	return -ENOMEM;
376 }
377 
378 static void nvmet_rdma_free_rsp(struct nvmet_rdma_device *ndev,
379 		struct nvmet_rdma_rsp *r)
380 {
381 	ib_dma_unmap_single(ndev->device, r->send_sge.addr,
382 				sizeof(*r->req.rsp), DMA_TO_DEVICE);
383 	kfree(r->req.rsp);
384 }
385 
386 static int
387 nvmet_rdma_alloc_rsps(struct nvmet_rdma_queue *queue)
388 {
389 	struct nvmet_rdma_device *ndev = queue->dev;
390 	int nr_rsps = queue->recv_queue_size * 2;
391 	int ret = -EINVAL, i;
392 
393 	queue->rsps = kcalloc(nr_rsps, sizeof(struct nvmet_rdma_rsp),
394 			GFP_KERNEL);
395 	if (!queue->rsps)
396 		goto out;
397 
398 	for (i = 0; i < nr_rsps; i++) {
399 		struct nvmet_rdma_rsp *rsp = &queue->rsps[i];
400 
401 		ret = nvmet_rdma_alloc_rsp(ndev, rsp);
402 		if (ret)
403 			goto out_free;
404 
405 		list_add_tail(&rsp->free_list, &queue->free_rsps);
406 	}
407 
408 	return 0;
409 
410 out_free:
411 	while (--i >= 0) {
412 		struct nvmet_rdma_rsp *rsp = &queue->rsps[i];
413 
414 		list_del(&rsp->free_list);
415 		nvmet_rdma_free_rsp(ndev, rsp);
416 	}
417 	kfree(queue->rsps);
418 out:
419 	return ret;
420 }
421 
422 static void nvmet_rdma_free_rsps(struct nvmet_rdma_queue *queue)
423 {
424 	struct nvmet_rdma_device *ndev = queue->dev;
425 	int i, nr_rsps = queue->recv_queue_size * 2;
426 
427 	for (i = 0; i < nr_rsps; i++) {
428 		struct nvmet_rdma_rsp *rsp = &queue->rsps[i];
429 
430 		list_del(&rsp->free_list);
431 		nvmet_rdma_free_rsp(ndev, rsp);
432 	}
433 	kfree(queue->rsps);
434 }
435 
436 static int nvmet_rdma_post_recv(struct nvmet_rdma_device *ndev,
437 		struct nvmet_rdma_cmd *cmd)
438 {
439 	struct ib_recv_wr *bad_wr;
440 
441 	ib_dma_sync_single_for_device(ndev->device,
442 		cmd->sge[0].addr, cmd->sge[0].length,
443 		DMA_FROM_DEVICE);
444 
445 	if (ndev->srq)
446 		return ib_post_srq_recv(ndev->srq, &cmd->wr, &bad_wr);
447 	return ib_post_recv(cmd->queue->cm_id->qp, &cmd->wr, &bad_wr);
448 }
449 
450 static void nvmet_rdma_process_wr_wait_list(struct nvmet_rdma_queue *queue)
451 {
452 	spin_lock(&queue->rsp_wr_wait_lock);
453 	while (!list_empty(&queue->rsp_wr_wait_list)) {
454 		struct nvmet_rdma_rsp *rsp;
455 		bool ret;
456 
457 		rsp = list_entry(queue->rsp_wr_wait_list.next,
458 				struct nvmet_rdma_rsp, wait_list);
459 		list_del(&rsp->wait_list);
460 
461 		spin_unlock(&queue->rsp_wr_wait_lock);
462 		ret = nvmet_rdma_execute_command(rsp);
463 		spin_lock(&queue->rsp_wr_wait_lock);
464 
465 		if (!ret) {
466 			list_add(&rsp->wait_list, &queue->rsp_wr_wait_list);
467 			break;
468 		}
469 	}
470 	spin_unlock(&queue->rsp_wr_wait_lock);
471 }
472 
473 
474 static void nvmet_rdma_release_rsp(struct nvmet_rdma_rsp *rsp)
475 {
476 	struct nvmet_rdma_queue *queue = rsp->queue;
477 
478 	atomic_add(1 + rsp->n_rdma, &queue->sq_wr_avail);
479 
480 	if (rsp->n_rdma) {
481 		rdma_rw_ctx_destroy(&rsp->rw, queue->cm_id->qp,
482 				queue->cm_id->port_num, rsp->req.sg,
483 				rsp->req.sg_cnt, nvmet_data_dir(&rsp->req));
484 	}
485 
486 	if (rsp->req.sg != &rsp->cmd->inline_sg)
487 		nvmet_rdma_free_sgl(rsp->req.sg, rsp->req.sg_cnt);
488 
489 	if (unlikely(!list_empty_careful(&queue->rsp_wr_wait_list)))
490 		nvmet_rdma_process_wr_wait_list(queue);
491 
492 	nvmet_rdma_put_rsp(rsp);
493 }
494 
495 static void nvmet_rdma_error_comp(struct nvmet_rdma_queue *queue)
496 {
497 	if (queue->nvme_sq.ctrl) {
498 		nvmet_ctrl_fatal_error(queue->nvme_sq.ctrl);
499 	} else {
500 		/*
501 		 * we didn't setup the controller yet in case
502 		 * of admin connect error, just disconnect and
503 		 * cleanup the queue
504 		 */
505 		nvmet_rdma_queue_disconnect(queue);
506 	}
507 }
508 
509 static void nvmet_rdma_send_done(struct ib_cq *cq, struct ib_wc *wc)
510 {
511 	struct nvmet_rdma_rsp *rsp =
512 		container_of(wc->wr_cqe, struct nvmet_rdma_rsp, send_cqe);
513 
514 	nvmet_rdma_release_rsp(rsp);
515 
516 	if (unlikely(wc->status != IB_WC_SUCCESS &&
517 		     wc->status != IB_WC_WR_FLUSH_ERR)) {
518 		pr_err("SEND for CQE 0x%p failed with status %s (%d).\n",
519 			wc->wr_cqe, ib_wc_status_msg(wc->status), wc->status);
520 		nvmet_rdma_error_comp(rsp->queue);
521 	}
522 }
523 
524 static void nvmet_rdma_queue_response(struct nvmet_req *req)
525 {
526 	struct nvmet_rdma_rsp *rsp =
527 		container_of(req, struct nvmet_rdma_rsp, req);
528 	struct rdma_cm_id *cm_id = rsp->queue->cm_id;
529 	struct ib_send_wr *first_wr, *bad_wr;
530 
531 	if (rsp->flags & NVMET_RDMA_REQ_INVALIDATE_RKEY) {
532 		rsp->send_wr.opcode = IB_WR_SEND_WITH_INV;
533 		rsp->send_wr.ex.invalidate_rkey = rsp->invalidate_rkey;
534 	} else {
535 		rsp->send_wr.opcode = IB_WR_SEND;
536 	}
537 
538 	if (nvmet_rdma_need_data_out(rsp))
539 		first_wr = rdma_rw_ctx_wrs(&rsp->rw, cm_id->qp,
540 				cm_id->port_num, NULL, &rsp->send_wr);
541 	else
542 		first_wr = &rsp->send_wr;
543 
544 	nvmet_rdma_post_recv(rsp->queue->dev, rsp->cmd);
545 
546 	ib_dma_sync_single_for_device(rsp->queue->dev->device,
547 		rsp->send_sge.addr, rsp->send_sge.length,
548 		DMA_TO_DEVICE);
549 
550 	if (ib_post_send(cm_id->qp, first_wr, &bad_wr)) {
551 		pr_err("sending cmd response failed\n");
552 		nvmet_rdma_release_rsp(rsp);
553 	}
554 }
555 
556 static void nvmet_rdma_read_data_done(struct ib_cq *cq, struct ib_wc *wc)
557 {
558 	struct nvmet_rdma_rsp *rsp =
559 		container_of(wc->wr_cqe, struct nvmet_rdma_rsp, read_cqe);
560 	struct nvmet_rdma_queue *queue = cq->cq_context;
561 
562 	WARN_ON(rsp->n_rdma <= 0);
563 	atomic_add(rsp->n_rdma, &queue->sq_wr_avail);
564 	rdma_rw_ctx_destroy(&rsp->rw, queue->cm_id->qp,
565 			queue->cm_id->port_num, rsp->req.sg,
566 			rsp->req.sg_cnt, nvmet_data_dir(&rsp->req));
567 	rsp->n_rdma = 0;
568 
569 	if (unlikely(wc->status != IB_WC_SUCCESS)) {
570 		nvmet_rdma_release_rsp(rsp);
571 		if (wc->status != IB_WC_WR_FLUSH_ERR) {
572 			pr_info("RDMA READ for CQE 0x%p failed with status %s (%d).\n",
573 				wc->wr_cqe, ib_wc_status_msg(wc->status), wc->status);
574 			nvmet_rdma_error_comp(queue);
575 		}
576 		return;
577 	}
578 
579 	rsp->req.execute(&rsp->req);
580 }
581 
582 static void nvmet_rdma_use_inline_sg(struct nvmet_rdma_rsp *rsp, u32 len,
583 		u64 off)
584 {
585 	sg_init_table(&rsp->cmd->inline_sg, 1);
586 	sg_set_page(&rsp->cmd->inline_sg, rsp->cmd->inline_page, len, off);
587 	rsp->req.sg = &rsp->cmd->inline_sg;
588 	rsp->req.sg_cnt = 1;
589 }
590 
591 static u16 nvmet_rdma_map_sgl_inline(struct nvmet_rdma_rsp *rsp)
592 {
593 	struct nvme_sgl_desc *sgl = &rsp->req.cmd->common.dptr.sgl;
594 	u64 off = le64_to_cpu(sgl->addr);
595 	u32 len = le32_to_cpu(sgl->length);
596 
597 	if (!nvme_is_write(rsp->req.cmd))
598 		return NVME_SC_INVALID_FIELD | NVME_SC_DNR;
599 
600 	if (off + len > NVMET_RDMA_INLINE_DATA_SIZE) {
601 		pr_err("invalid inline data offset!\n");
602 		return NVME_SC_SGL_INVALID_OFFSET | NVME_SC_DNR;
603 	}
604 
605 	/* no data command? */
606 	if (!len)
607 		return 0;
608 
609 	nvmet_rdma_use_inline_sg(rsp, len, off);
610 	rsp->flags |= NVMET_RDMA_REQ_INLINE_DATA;
611 	return 0;
612 }
613 
614 static u16 nvmet_rdma_map_sgl_keyed(struct nvmet_rdma_rsp *rsp,
615 		struct nvme_keyed_sgl_desc *sgl, bool invalidate)
616 {
617 	struct rdma_cm_id *cm_id = rsp->queue->cm_id;
618 	u64 addr = le64_to_cpu(sgl->addr);
619 	u32 len = get_unaligned_le24(sgl->length);
620 	u32 key = get_unaligned_le32(sgl->key);
621 	int ret;
622 	u16 status;
623 
624 	/* no data command? */
625 	if (!len)
626 		return 0;
627 
628 	status = nvmet_rdma_alloc_sgl(&rsp->req.sg, &rsp->req.sg_cnt,
629 			len);
630 	if (status)
631 		return status;
632 
633 	ret = rdma_rw_ctx_init(&rsp->rw, cm_id->qp, cm_id->port_num,
634 			rsp->req.sg, rsp->req.sg_cnt, 0, addr, key,
635 			nvmet_data_dir(&rsp->req));
636 	if (ret < 0)
637 		return NVME_SC_INTERNAL;
638 	rsp->n_rdma += ret;
639 
640 	if (invalidate) {
641 		rsp->invalidate_rkey = key;
642 		rsp->flags |= NVMET_RDMA_REQ_INVALIDATE_RKEY;
643 	}
644 
645 	return 0;
646 }
647 
648 static u16 nvmet_rdma_map_sgl(struct nvmet_rdma_rsp *rsp)
649 {
650 	struct nvme_keyed_sgl_desc *sgl = &rsp->req.cmd->common.dptr.ksgl;
651 
652 	switch (sgl->type >> 4) {
653 	case NVME_SGL_FMT_DATA_DESC:
654 		switch (sgl->type & 0xf) {
655 		case NVME_SGL_FMT_OFFSET:
656 			return nvmet_rdma_map_sgl_inline(rsp);
657 		default:
658 			pr_err("invalid SGL subtype: %#x\n", sgl->type);
659 			return NVME_SC_INVALID_FIELD | NVME_SC_DNR;
660 		}
661 	case NVME_KEY_SGL_FMT_DATA_DESC:
662 		switch (sgl->type & 0xf) {
663 		case NVME_SGL_FMT_ADDRESS | NVME_SGL_FMT_INVALIDATE:
664 			return nvmet_rdma_map_sgl_keyed(rsp, sgl, true);
665 		case NVME_SGL_FMT_ADDRESS:
666 			return nvmet_rdma_map_sgl_keyed(rsp, sgl, false);
667 		default:
668 			pr_err("invalid SGL subtype: %#x\n", sgl->type);
669 			return NVME_SC_INVALID_FIELD | NVME_SC_DNR;
670 		}
671 	default:
672 		pr_err("invalid SGL type: %#x\n", sgl->type);
673 		return NVME_SC_SGL_INVALID_TYPE | NVME_SC_DNR;
674 	}
675 }
676 
677 static bool nvmet_rdma_execute_command(struct nvmet_rdma_rsp *rsp)
678 {
679 	struct nvmet_rdma_queue *queue = rsp->queue;
680 
681 	if (unlikely(atomic_sub_return(1 + rsp->n_rdma,
682 			&queue->sq_wr_avail) < 0)) {
683 		pr_debug("IB send queue full (needed %d): queue %u cntlid %u\n",
684 				1 + rsp->n_rdma, queue->idx,
685 				queue->nvme_sq.ctrl->cntlid);
686 		atomic_add(1 + rsp->n_rdma, &queue->sq_wr_avail);
687 		return false;
688 	}
689 
690 	if (nvmet_rdma_need_data_in(rsp)) {
691 		if (rdma_rw_ctx_post(&rsp->rw, queue->cm_id->qp,
692 				queue->cm_id->port_num, &rsp->read_cqe, NULL))
693 			nvmet_req_complete(&rsp->req, NVME_SC_DATA_XFER_ERROR);
694 	} else {
695 		rsp->req.execute(&rsp->req);
696 	}
697 
698 	return true;
699 }
700 
701 static void nvmet_rdma_handle_command(struct nvmet_rdma_queue *queue,
702 		struct nvmet_rdma_rsp *cmd)
703 {
704 	u16 status;
705 
706 	ib_dma_sync_single_for_cpu(queue->dev->device,
707 		cmd->cmd->sge[0].addr, cmd->cmd->sge[0].length,
708 		DMA_FROM_DEVICE);
709 	ib_dma_sync_single_for_cpu(queue->dev->device,
710 		cmd->send_sge.addr, cmd->send_sge.length,
711 		DMA_TO_DEVICE);
712 
713 	if (!nvmet_req_init(&cmd->req, &queue->nvme_cq,
714 			&queue->nvme_sq, &nvmet_rdma_ops))
715 		return;
716 
717 	status = nvmet_rdma_map_sgl(cmd);
718 	if (status)
719 		goto out_err;
720 
721 	if (unlikely(!nvmet_rdma_execute_command(cmd))) {
722 		spin_lock(&queue->rsp_wr_wait_lock);
723 		list_add_tail(&cmd->wait_list, &queue->rsp_wr_wait_list);
724 		spin_unlock(&queue->rsp_wr_wait_lock);
725 	}
726 
727 	return;
728 
729 out_err:
730 	nvmet_req_complete(&cmd->req, status);
731 }
732 
733 static void nvmet_rdma_recv_done(struct ib_cq *cq, struct ib_wc *wc)
734 {
735 	struct nvmet_rdma_cmd *cmd =
736 		container_of(wc->wr_cqe, struct nvmet_rdma_cmd, cqe);
737 	struct nvmet_rdma_queue *queue = cq->cq_context;
738 	struct nvmet_rdma_rsp *rsp;
739 
740 	if (unlikely(wc->status != IB_WC_SUCCESS)) {
741 		if (wc->status != IB_WC_WR_FLUSH_ERR) {
742 			pr_err("RECV for CQE 0x%p failed with status %s (%d)\n",
743 				wc->wr_cqe, ib_wc_status_msg(wc->status),
744 				wc->status);
745 			nvmet_rdma_error_comp(queue);
746 		}
747 		return;
748 	}
749 
750 	if (unlikely(wc->byte_len < sizeof(struct nvme_command))) {
751 		pr_err("Ctrl Fatal Error: capsule size less than 64 bytes\n");
752 		nvmet_rdma_error_comp(queue);
753 		return;
754 	}
755 
756 	cmd->queue = queue;
757 	rsp = nvmet_rdma_get_rsp(queue);
758 	rsp->queue = queue;
759 	rsp->cmd = cmd;
760 	rsp->flags = 0;
761 	rsp->req.cmd = cmd->nvme_cmd;
762 	rsp->req.port = queue->port;
763 	rsp->n_rdma = 0;
764 
765 	if (unlikely(queue->state != NVMET_RDMA_Q_LIVE)) {
766 		unsigned long flags;
767 
768 		spin_lock_irqsave(&queue->state_lock, flags);
769 		if (queue->state == NVMET_RDMA_Q_CONNECTING)
770 			list_add_tail(&rsp->wait_list, &queue->rsp_wait_list);
771 		else
772 			nvmet_rdma_put_rsp(rsp);
773 		spin_unlock_irqrestore(&queue->state_lock, flags);
774 		return;
775 	}
776 
777 	nvmet_rdma_handle_command(queue, rsp);
778 }
779 
780 static void nvmet_rdma_destroy_srq(struct nvmet_rdma_device *ndev)
781 {
782 	if (!ndev->srq)
783 		return;
784 
785 	nvmet_rdma_free_cmds(ndev, ndev->srq_cmds, ndev->srq_size, false);
786 	ib_destroy_srq(ndev->srq);
787 }
788 
789 static int nvmet_rdma_init_srq(struct nvmet_rdma_device *ndev)
790 {
791 	struct ib_srq_init_attr srq_attr = { NULL, };
792 	struct ib_srq *srq;
793 	size_t srq_size;
794 	int ret, i;
795 
796 	srq_size = 4095;	/* XXX: tune */
797 
798 	srq_attr.attr.max_wr = srq_size;
799 	srq_attr.attr.max_sge = 2;
800 	srq_attr.attr.srq_limit = 0;
801 	srq_attr.srq_type = IB_SRQT_BASIC;
802 	srq = ib_create_srq(ndev->pd, &srq_attr);
803 	if (IS_ERR(srq)) {
804 		/*
805 		 * If SRQs aren't supported we just go ahead and use normal
806 		 * non-shared receive queues.
807 		 */
808 		pr_info("SRQ requested but not supported.\n");
809 		return 0;
810 	}
811 
812 	ndev->srq_cmds = nvmet_rdma_alloc_cmds(ndev, srq_size, false);
813 	if (IS_ERR(ndev->srq_cmds)) {
814 		ret = PTR_ERR(ndev->srq_cmds);
815 		goto out_destroy_srq;
816 	}
817 
818 	ndev->srq = srq;
819 	ndev->srq_size = srq_size;
820 
821 	for (i = 0; i < srq_size; i++)
822 		nvmet_rdma_post_recv(ndev, &ndev->srq_cmds[i]);
823 
824 	return 0;
825 
826 out_destroy_srq:
827 	ib_destroy_srq(srq);
828 	return ret;
829 }
830 
831 static void nvmet_rdma_free_dev(struct kref *ref)
832 {
833 	struct nvmet_rdma_device *ndev =
834 		container_of(ref, struct nvmet_rdma_device, ref);
835 
836 	mutex_lock(&device_list_mutex);
837 	list_del(&ndev->entry);
838 	mutex_unlock(&device_list_mutex);
839 
840 	nvmet_rdma_destroy_srq(ndev);
841 	ib_dealloc_pd(ndev->pd);
842 
843 	kfree(ndev);
844 }
845 
846 static struct nvmet_rdma_device *
847 nvmet_rdma_find_get_device(struct rdma_cm_id *cm_id)
848 {
849 	struct nvmet_rdma_device *ndev;
850 	int ret;
851 
852 	mutex_lock(&device_list_mutex);
853 	list_for_each_entry(ndev, &device_list, entry) {
854 		if (ndev->device->node_guid == cm_id->device->node_guid &&
855 		    kref_get_unless_zero(&ndev->ref))
856 			goto out_unlock;
857 	}
858 
859 	ndev = kzalloc(sizeof(*ndev), GFP_KERNEL);
860 	if (!ndev)
861 		goto out_err;
862 
863 	ndev->device = cm_id->device;
864 	kref_init(&ndev->ref);
865 
866 	ndev->pd = ib_alloc_pd(ndev->device, 0);
867 	if (IS_ERR(ndev->pd))
868 		goto out_free_dev;
869 
870 	if (nvmet_rdma_use_srq) {
871 		ret = nvmet_rdma_init_srq(ndev);
872 		if (ret)
873 			goto out_free_pd;
874 	}
875 
876 	list_add(&ndev->entry, &device_list);
877 out_unlock:
878 	mutex_unlock(&device_list_mutex);
879 	pr_debug("added %s.\n", ndev->device->name);
880 	return ndev;
881 
882 out_free_pd:
883 	ib_dealloc_pd(ndev->pd);
884 out_free_dev:
885 	kfree(ndev);
886 out_err:
887 	mutex_unlock(&device_list_mutex);
888 	return NULL;
889 }
890 
891 static int nvmet_rdma_create_queue_ib(struct nvmet_rdma_queue *queue)
892 {
893 	struct ib_qp_init_attr qp_attr;
894 	struct nvmet_rdma_device *ndev = queue->dev;
895 	int comp_vector, nr_cqe, ret, i;
896 
897 	/*
898 	 * Spread the io queues across completion vectors,
899 	 * but still keep all admin queues on vector 0.
900 	 */
901 	comp_vector = !queue->host_qid ? 0 :
902 		queue->idx % ndev->device->num_comp_vectors;
903 
904 	/*
905 	 * Reserve CQ slots for RECV + RDMA_READ/RDMA_WRITE + RDMA_SEND.
906 	 */
907 	nr_cqe = queue->recv_queue_size + 2 * queue->send_queue_size;
908 
909 	queue->cq = ib_alloc_cq(ndev->device, queue,
910 			nr_cqe + 1, comp_vector,
911 			IB_POLL_WORKQUEUE);
912 	if (IS_ERR(queue->cq)) {
913 		ret = PTR_ERR(queue->cq);
914 		pr_err("failed to create CQ cqe= %d ret= %d\n",
915 		       nr_cqe + 1, ret);
916 		goto out;
917 	}
918 
919 	memset(&qp_attr, 0, sizeof(qp_attr));
920 	qp_attr.qp_context = queue;
921 	qp_attr.event_handler = nvmet_rdma_qp_event;
922 	qp_attr.send_cq = queue->cq;
923 	qp_attr.recv_cq = queue->cq;
924 	qp_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
925 	qp_attr.qp_type = IB_QPT_RC;
926 	/* +1 for drain */
927 	qp_attr.cap.max_send_wr = queue->send_queue_size + 1;
928 	qp_attr.cap.max_rdma_ctxs = queue->send_queue_size;
929 	qp_attr.cap.max_send_sge = max(ndev->device->attrs.max_sge_rd,
930 					ndev->device->attrs.max_sge);
931 
932 	if (ndev->srq) {
933 		qp_attr.srq = ndev->srq;
934 	} else {
935 		/* +1 for drain */
936 		qp_attr.cap.max_recv_wr = 1 + queue->recv_queue_size;
937 		qp_attr.cap.max_recv_sge = 2;
938 	}
939 
940 	ret = rdma_create_qp(queue->cm_id, ndev->pd, &qp_attr);
941 	if (ret) {
942 		pr_err("failed to create_qp ret= %d\n", ret);
943 		goto err_destroy_cq;
944 	}
945 
946 	atomic_set(&queue->sq_wr_avail, qp_attr.cap.max_send_wr);
947 
948 	pr_debug("%s: max_cqe= %d max_sge= %d sq_size = %d cm_id= %p\n",
949 		 __func__, queue->cq->cqe, qp_attr.cap.max_send_sge,
950 		 qp_attr.cap.max_send_wr, queue->cm_id);
951 
952 	if (!ndev->srq) {
953 		for (i = 0; i < queue->recv_queue_size; i++) {
954 			queue->cmds[i].queue = queue;
955 			nvmet_rdma_post_recv(ndev, &queue->cmds[i]);
956 		}
957 	}
958 
959 out:
960 	return ret;
961 
962 err_destroy_cq:
963 	ib_free_cq(queue->cq);
964 	goto out;
965 }
966 
967 static void nvmet_rdma_destroy_queue_ib(struct nvmet_rdma_queue *queue)
968 {
969 	ib_drain_qp(queue->cm_id->qp);
970 	rdma_destroy_qp(queue->cm_id);
971 	ib_free_cq(queue->cq);
972 }
973 
974 static void nvmet_rdma_free_queue(struct nvmet_rdma_queue *queue)
975 {
976 	pr_info("freeing queue %d\n", queue->idx);
977 
978 	nvmet_sq_destroy(&queue->nvme_sq);
979 
980 	nvmet_rdma_destroy_queue_ib(queue);
981 	if (!queue->dev->srq) {
982 		nvmet_rdma_free_cmds(queue->dev, queue->cmds,
983 				queue->recv_queue_size,
984 				!queue->host_qid);
985 	}
986 	nvmet_rdma_free_rsps(queue);
987 	ida_simple_remove(&nvmet_rdma_queue_ida, queue->idx);
988 	kfree(queue);
989 }
990 
991 static void nvmet_rdma_release_queue_work(struct work_struct *w)
992 {
993 	struct nvmet_rdma_queue *queue =
994 		container_of(w, struct nvmet_rdma_queue, release_work);
995 	struct rdma_cm_id *cm_id = queue->cm_id;
996 	struct nvmet_rdma_device *dev = queue->dev;
997 	enum nvmet_rdma_queue_state state = queue->state;
998 
999 	nvmet_rdma_free_queue(queue);
1000 
1001 	if (state != NVMET_RDMA_IN_DEVICE_REMOVAL)
1002 		rdma_destroy_id(cm_id);
1003 
1004 	kref_put(&dev->ref, nvmet_rdma_free_dev);
1005 }
1006 
1007 static int
1008 nvmet_rdma_parse_cm_connect_req(struct rdma_conn_param *conn,
1009 				struct nvmet_rdma_queue *queue)
1010 {
1011 	struct nvme_rdma_cm_req *req;
1012 
1013 	req = (struct nvme_rdma_cm_req *)conn->private_data;
1014 	if (!req || conn->private_data_len == 0)
1015 		return NVME_RDMA_CM_INVALID_LEN;
1016 
1017 	if (le16_to_cpu(req->recfmt) != NVME_RDMA_CM_FMT_1_0)
1018 		return NVME_RDMA_CM_INVALID_RECFMT;
1019 
1020 	queue->host_qid = le16_to_cpu(req->qid);
1021 
1022 	/*
1023 	 * req->hsqsize corresponds to our recv queue size plus 1
1024 	 * req->hrqsize corresponds to our send queue size
1025 	 */
1026 	queue->recv_queue_size = le16_to_cpu(req->hsqsize) + 1;
1027 	queue->send_queue_size = le16_to_cpu(req->hrqsize);
1028 
1029 	if (!queue->host_qid && queue->recv_queue_size > NVMF_AQ_DEPTH)
1030 		return NVME_RDMA_CM_INVALID_HSQSIZE;
1031 
1032 	/* XXX: Should we enforce some kind of max for IO queues? */
1033 
1034 	return 0;
1035 }
1036 
1037 static int nvmet_rdma_cm_reject(struct rdma_cm_id *cm_id,
1038 				enum nvme_rdma_cm_status status)
1039 {
1040 	struct nvme_rdma_cm_rej rej;
1041 
1042 	pr_debug("rejecting connect request: status %d (%s)\n",
1043 		 status, nvme_rdma_cm_msg(status));
1044 
1045 	rej.recfmt = cpu_to_le16(NVME_RDMA_CM_FMT_1_0);
1046 	rej.sts = cpu_to_le16(status);
1047 
1048 	return rdma_reject(cm_id, (void *)&rej, sizeof(rej));
1049 }
1050 
1051 static struct nvmet_rdma_queue *
1052 nvmet_rdma_alloc_queue(struct nvmet_rdma_device *ndev,
1053 		struct rdma_cm_id *cm_id,
1054 		struct rdma_cm_event *event)
1055 {
1056 	struct nvmet_rdma_queue *queue;
1057 	int ret;
1058 
1059 	queue = kzalloc(sizeof(*queue), GFP_KERNEL);
1060 	if (!queue) {
1061 		ret = NVME_RDMA_CM_NO_RSC;
1062 		goto out_reject;
1063 	}
1064 
1065 	ret = nvmet_sq_init(&queue->nvme_sq);
1066 	if (ret) {
1067 		ret = NVME_RDMA_CM_NO_RSC;
1068 		goto out_free_queue;
1069 	}
1070 
1071 	ret = nvmet_rdma_parse_cm_connect_req(&event->param.conn, queue);
1072 	if (ret)
1073 		goto out_destroy_sq;
1074 
1075 	/*
1076 	 * Schedules the actual release because calling rdma_destroy_id from
1077 	 * inside a CM callback would trigger a deadlock. (great API design..)
1078 	 */
1079 	INIT_WORK(&queue->release_work, nvmet_rdma_release_queue_work);
1080 	queue->dev = ndev;
1081 	queue->cm_id = cm_id;
1082 
1083 	spin_lock_init(&queue->state_lock);
1084 	queue->state = NVMET_RDMA_Q_CONNECTING;
1085 	INIT_LIST_HEAD(&queue->rsp_wait_list);
1086 	INIT_LIST_HEAD(&queue->rsp_wr_wait_list);
1087 	spin_lock_init(&queue->rsp_wr_wait_lock);
1088 	INIT_LIST_HEAD(&queue->free_rsps);
1089 	spin_lock_init(&queue->rsps_lock);
1090 	INIT_LIST_HEAD(&queue->queue_list);
1091 
1092 	queue->idx = ida_simple_get(&nvmet_rdma_queue_ida, 0, 0, GFP_KERNEL);
1093 	if (queue->idx < 0) {
1094 		ret = NVME_RDMA_CM_NO_RSC;
1095 		goto out_destroy_sq;
1096 	}
1097 
1098 	ret = nvmet_rdma_alloc_rsps(queue);
1099 	if (ret) {
1100 		ret = NVME_RDMA_CM_NO_RSC;
1101 		goto out_ida_remove;
1102 	}
1103 
1104 	if (!ndev->srq) {
1105 		queue->cmds = nvmet_rdma_alloc_cmds(ndev,
1106 				queue->recv_queue_size,
1107 				!queue->host_qid);
1108 		if (IS_ERR(queue->cmds)) {
1109 			ret = NVME_RDMA_CM_NO_RSC;
1110 			goto out_free_responses;
1111 		}
1112 	}
1113 
1114 	ret = nvmet_rdma_create_queue_ib(queue);
1115 	if (ret) {
1116 		pr_err("%s: creating RDMA queue failed (%d).\n",
1117 			__func__, ret);
1118 		ret = NVME_RDMA_CM_NO_RSC;
1119 		goto out_free_cmds;
1120 	}
1121 
1122 	return queue;
1123 
1124 out_free_cmds:
1125 	if (!ndev->srq) {
1126 		nvmet_rdma_free_cmds(queue->dev, queue->cmds,
1127 				queue->recv_queue_size,
1128 				!queue->host_qid);
1129 	}
1130 out_free_responses:
1131 	nvmet_rdma_free_rsps(queue);
1132 out_ida_remove:
1133 	ida_simple_remove(&nvmet_rdma_queue_ida, queue->idx);
1134 out_destroy_sq:
1135 	nvmet_sq_destroy(&queue->nvme_sq);
1136 out_free_queue:
1137 	kfree(queue);
1138 out_reject:
1139 	nvmet_rdma_cm_reject(cm_id, ret);
1140 	return NULL;
1141 }
1142 
1143 static void nvmet_rdma_qp_event(struct ib_event *event, void *priv)
1144 {
1145 	struct nvmet_rdma_queue *queue = priv;
1146 
1147 	switch (event->event) {
1148 	case IB_EVENT_COMM_EST:
1149 		rdma_notify(queue->cm_id, event->event);
1150 		break;
1151 	default:
1152 		pr_err("received IB QP event: %s (%d)\n",
1153 		       ib_event_msg(event->event), event->event);
1154 		break;
1155 	}
1156 }
1157 
1158 static int nvmet_rdma_cm_accept(struct rdma_cm_id *cm_id,
1159 		struct nvmet_rdma_queue *queue,
1160 		struct rdma_conn_param *p)
1161 {
1162 	struct rdma_conn_param  param = { };
1163 	struct nvme_rdma_cm_rep priv = { };
1164 	int ret = -ENOMEM;
1165 
1166 	param.rnr_retry_count = 7;
1167 	param.flow_control = 1;
1168 	param.initiator_depth = min_t(u8, p->initiator_depth,
1169 		queue->dev->device->attrs.max_qp_init_rd_atom);
1170 	param.private_data = &priv;
1171 	param.private_data_len = sizeof(priv);
1172 	priv.recfmt = cpu_to_le16(NVME_RDMA_CM_FMT_1_0);
1173 	priv.crqsize = cpu_to_le16(queue->recv_queue_size);
1174 
1175 	ret = rdma_accept(cm_id, &param);
1176 	if (ret)
1177 		pr_err("rdma_accept failed (error code = %d)\n", ret);
1178 
1179 	return ret;
1180 }
1181 
1182 static int nvmet_rdma_queue_connect(struct rdma_cm_id *cm_id,
1183 		struct rdma_cm_event *event)
1184 {
1185 	struct nvmet_rdma_device *ndev;
1186 	struct nvmet_rdma_queue *queue;
1187 	int ret = -EINVAL;
1188 
1189 	ndev = nvmet_rdma_find_get_device(cm_id);
1190 	if (!ndev) {
1191 		nvmet_rdma_cm_reject(cm_id, NVME_RDMA_CM_NO_RSC);
1192 		return -ECONNREFUSED;
1193 	}
1194 
1195 	queue = nvmet_rdma_alloc_queue(ndev, cm_id, event);
1196 	if (!queue) {
1197 		ret = -ENOMEM;
1198 		goto put_device;
1199 	}
1200 	queue->port = cm_id->context;
1201 
1202 	ret = nvmet_rdma_cm_accept(cm_id, queue, &event->param.conn);
1203 	if (ret)
1204 		goto release_queue;
1205 
1206 	mutex_lock(&nvmet_rdma_queue_mutex);
1207 	list_add_tail(&queue->queue_list, &nvmet_rdma_queue_list);
1208 	mutex_unlock(&nvmet_rdma_queue_mutex);
1209 
1210 	return 0;
1211 
1212 release_queue:
1213 	nvmet_rdma_free_queue(queue);
1214 put_device:
1215 	kref_put(&ndev->ref, nvmet_rdma_free_dev);
1216 
1217 	return ret;
1218 }
1219 
1220 static void nvmet_rdma_queue_established(struct nvmet_rdma_queue *queue)
1221 {
1222 	unsigned long flags;
1223 
1224 	spin_lock_irqsave(&queue->state_lock, flags);
1225 	if (queue->state != NVMET_RDMA_Q_CONNECTING) {
1226 		pr_warn("trying to establish a connected queue\n");
1227 		goto out_unlock;
1228 	}
1229 	queue->state = NVMET_RDMA_Q_LIVE;
1230 
1231 	while (!list_empty(&queue->rsp_wait_list)) {
1232 		struct nvmet_rdma_rsp *cmd;
1233 
1234 		cmd = list_first_entry(&queue->rsp_wait_list,
1235 					struct nvmet_rdma_rsp, wait_list);
1236 		list_del(&cmd->wait_list);
1237 
1238 		spin_unlock_irqrestore(&queue->state_lock, flags);
1239 		nvmet_rdma_handle_command(queue, cmd);
1240 		spin_lock_irqsave(&queue->state_lock, flags);
1241 	}
1242 
1243 out_unlock:
1244 	spin_unlock_irqrestore(&queue->state_lock, flags);
1245 }
1246 
1247 static void __nvmet_rdma_queue_disconnect(struct nvmet_rdma_queue *queue)
1248 {
1249 	bool disconnect = false;
1250 	unsigned long flags;
1251 
1252 	pr_debug("cm_id= %p queue->state= %d\n", queue->cm_id, queue->state);
1253 
1254 	spin_lock_irqsave(&queue->state_lock, flags);
1255 	switch (queue->state) {
1256 	case NVMET_RDMA_Q_CONNECTING:
1257 	case NVMET_RDMA_Q_LIVE:
1258 		queue->state = NVMET_RDMA_Q_DISCONNECTING;
1259 	case NVMET_RDMA_IN_DEVICE_REMOVAL:
1260 		disconnect = true;
1261 		break;
1262 	case NVMET_RDMA_Q_DISCONNECTING:
1263 		break;
1264 	}
1265 	spin_unlock_irqrestore(&queue->state_lock, flags);
1266 
1267 	if (disconnect) {
1268 		rdma_disconnect(queue->cm_id);
1269 		schedule_work(&queue->release_work);
1270 	}
1271 }
1272 
1273 static void nvmet_rdma_queue_disconnect(struct nvmet_rdma_queue *queue)
1274 {
1275 	bool disconnect = false;
1276 
1277 	mutex_lock(&nvmet_rdma_queue_mutex);
1278 	if (!list_empty(&queue->queue_list)) {
1279 		list_del_init(&queue->queue_list);
1280 		disconnect = true;
1281 	}
1282 	mutex_unlock(&nvmet_rdma_queue_mutex);
1283 
1284 	if (disconnect)
1285 		__nvmet_rdma_queue_disconnect(queue);
1286 }
1287 
1288 static void nvmet_rdma_queue_connect_fail(struct rdma_cm_id *cm_id,
1289 		struct nvmet_rdma_queue *queue)
1290 {
1291 	WARN_ON_ONCE(queue->state != NVMET_RDMA_Q_CONNECTING);
1292 
1293 	mutex_lock(&nvmet_rdma_queue_mutex);
1294 	if (!list_empty(&queue->queue_list))
1295 		list_del_init(&queue->queue_list);
1296 	mutex_unlock(&nvmet_rdma_queue_mutex);
1297 
1298 	pr_err("failed to connect queue %d\n", queue->idx);
1299 	schedule_work(&queue->release_work);
1300 }
1301 
1302 /**
1303  * nvme_rdma_device_removal() - Handle RDMA device removal
1304  * @queue:      nvmet rdma queue (cm id qp_context)
1305  * @addr:	nvmet address (cm_id context)
1306  *
1307  * DEVICE_REMOVAL event notifies us that the RDMA device is about
1308  * to unplug so we should take care of destroying our RDMA resources.
1309  * This event will be generated for each allocated cm_id.
1310  *
1311  * Note that this event can be generated on a normal queue cm_id
1312  * and/or a device bound listener cm_id (where in this case
1313  * queue will be null).
1314  *
1315  * we claim ownership on destroying the cm_id. For queues we move
1316  * the queue state to NVMET_RDMA_IN_DEVICE_REMOVAL and for port
1317  * we nullify the priv to prevent double cm_id destruction and destroying
1318  * the cm_id implicitely by returning a non-zero rc to the callout.
1319  */
1320 static int nvmet_rdma_device_removal(struct rdma_cm_id *cm_id,
1321 		struct nvmet_rdma_queue *queue)
1322 {
1323 	unsigned long flags;
1324 
1325 	if (!queue) {
1326 		struct nvmet_port *port = cm_id->context;
1327 
1328 		/*
1329 		 * This is a listener cm_id. Make sure that
1330 		 * future remove_port won't invoke a double
1331 		 * cm_id destroy. use atomic xchg to make sure
1332 		 * we don't compete with remove_port.
1333 		 */
1334 		if (xchg(&port->priv, NULL) != cm_id)
1335 			return 0;
1336 	} else {
1337 		/*
1338 		 * This is a queue cm_id. Make sure that
1339 		 * release queue will not destroy the cm_id
1340 		 * and schedule all ctrl queues removal (only
1341 		 * if the queue is not disconnecting already).
1342 		 */
1343 		spin_lock_irqsave(&queue->state_lock, flags);
1344 		if (queue->state != NVMET_RDMA_Q_DISCONNECTING)
1345 			queue->state = NVMET_RDMA_IN_DEVICE_REMOVAL;
1346 		spin_unlock_irqrestore(&queue->state_lock, flags);
1347 		nvmet_rdma_queue_disconnect(queue);
1348 		flush_scheduled_work();
1349 	}
1350 
1351 	/*
1352 	 * We need to return 1 so that the core will destroy
1353 	 * it's own ID.  What a great API design..
1354 	 */
1355 	return 1;
1356 }
1357 
1358 static int nvmet_rdma_cm_handler(struct rdma_cm_id *cm_id,
1359 		struct rdma_cm_event *event)
1360 {
1361 	struct nvmet_rdma_queue *queue = NULL;
1362 	int ret = 0;
1363 
1364 	if (cm_id->qp)
1365 		queue = cm_id->qp->qp_context;
1366 
1367 	pr_debug("%s (%d): status %d id %p\n",
1368 		rdma_event_msg(event->event), event->event,
1369 		event->status, cm_id);
1370 
1371 	switch (event->event) {
1372 	case RDMA_CM_EVENT_CONNECT_REQUEST:
1373 		ret = nvmet_rdma_queue_connect(cm_id, event);
1374 		break;
1375 	case RDMA_CM_EVENT_ESTABLISHED:
1376 		nvmet_rdma_queue_established(queue);
1377 		break;
1378 	case RDMA_CM_EVENT_ADDR_CHANGE:
1379 	case RDMA_CM_EVENT_DISCONNECTED:
1380 	case RDMA_CM_EVENT_TIMEWAIT_EXIT:
1381 		/*
1382 		 * We might end up here when we already freed the qp
1383 		 * which means queue release sequence is in progress,
1384 		 * so don't get in the way...
1385 		 */
1386 		if (queue)
1387 			nvmet_rdma_queue_disconnect(queue);
1388 		break;
1389 	case RDMA_CM_EVENT_DEVICE_REMOVAL:
1390 		ret = nvmet_rdma_device_removal(cm_id, queue);
1391 		break;
1392 	case RDMA_CM_EVENT_REJECTED:
1393 		pr_debug("Connection rejected: %s\n",
1394 			 rdma_reject_msg(cm_id, event->status));
1395 		/* FALLTHROUGH */
1396 	case RDMA_CM_EVENT_UNREACHABLE:
1397 	case RDMA_CM_EVENT_CONNECT_ERROR:
1398 		nvmet_rdma_queue_connect_fail(cm_id, queue);
1399 		break;
1400 	default:
1401 		pr_err("received unrecognized RDMA CM event %d\n",
1402 			event->event);
1403 		break;
1404 	}
1405 
1406 	return ret;
1407 }
1408 
1409 static void nvmet_rdma_delete_ctrl(struct nvmet_ctrl *ctrl)
1410 {
1411 	struct nvmet_rdma_queue *queue;
1412 
1413 restart:
1414 	mutex_lock(&nvmet_rdma_queue_mutex);
1415 	list_for_each_entry(queue, &nvmet_rdma_queue_list, queue_list) {
1416 		if (queue->nvme_sq.ctrl == ctrl) {
1417 			list_del_init(&queue->queue_list);
1418 			mutex_unlock(&nvmet_rdma_queue_mutex);
1419 
1420 			__nvmet_rdma_queue_disconnect(queue);
1421 			goto restart;
1422 		}
1423 	}
1424 	mutex_unlock(&nvmet_rdma_queue_mutex);
1425 }
1426 
1427 static int nvmet_rdma_add_port(struct nvmet_port *port)
1428 {
1429 	struct rdma_cm_id *cm_id;
1430 	struct sockaddr_in addr_in;
1431 	u16 port_in;
1432 	int ret;
1433 
1434 	switch (port->disc_addr.adrfam) {
1435 	case NVMF_ADDR_FAMILY_IP4:
1436 		break;
1437 	default:
1438 		pr_err("address family %d not supported\n",
1439 				port->disc_addr.adrfam);
1440 		return -EINVAL;
1441 	}
1442 
1443 	ret = kstrtou16(port->disc_addr.trsvcid, 0, &port_in);
1444 	if (ret)
1445 		return ret;
1446 
1447 	addr_in.sin_family = AF_INET;
1448 	addr_in.sin_addr.s_addr = in_aton(port->disc_addr.traddr);
1449 	addr_in.sin_port = htons(port_in);
1450 
1451 	cm_id = rdma_create_id(&init_net, nvmet_rdma_cm_handler, port,
1452 			RDMA_PS_TCP, IB_QPT_RC);
1453 	if (IS_ERR(cm_id)) {
1454 		pr_err("CM ID creation failed\n");
1455 		return PTR_ERR(cm_id);
1456 	}
1457 
1458 	ret = rdma_bind_addr(cm_id, (struct sockaddr *)&addr_in);
1459 	if (ret) {
1460 		pr_err("binding CM ID to %pISpc failed (%d)\n", &addr_in, ret);
1461 		goto out_destroy_id;
1462 	}
1463 
1464 	ret = rdma_listen(cm_id, 128);
1465 	if (ret) {
1466 		pr_err("listening to %pISpc failed (%d)\n", &addr_in, ret);
1467 		goto out_destroy_id;
1468 	}
1469 
1470 	pr_info("enabling port %d (%pISpc)\n",
1471 		le16_to_cpu(port->disc_addr.portid), &addr_in);
1472 	port->priv = cm_id;
1473 	return 0;
1474 
1475 out_destroy_id:
1476 	rdma_destroy_id(cm_id);
1477 	return ret;
1478 }
1479 
1480 static void nvmet_rdma_remove_port(struct nvmet_port *port)
1481 {
1482 	struct rdma_cm_id *cm_id = xchg(&port->priv, NULL);
1483 
1484 	if (cm_id)
1485 		rdma_destroy_id(cm_id);
1486 }
1487 
1488 static struct nvmet_fabrics_ops nvmet_rdma_ops = {
1489 	.owner			= THIS_MODULE,
1490 	.type			= NVMF_TRTYPE_RDMA,
1491 	.sqe_inline_size	= NVMET_RDMA_INLINE_DATA_SIZE,
1492 	.msdbd			= 1,
1493 	.has_keyed_sgls		= 1,
1494 	.add_port		= nvmet_rdma_add_port,
1495 	.remove_port		= nvmet_rdma_remove_port,
1496 	.queue_response		= nvmet_rdma_queue_response,
1497 	.delete_ctrl		= nvmet_rdma_delete_ctrl,
1498 };
1499 
1500 static int __init nvmet_rdma_init(void)
1501 {
1502 	return nvmet_register_transport(&nvmet_rdma_ops);
1503 }
1504 
1505 static void __exit nvmet_rdma_exit(void)
1506 {
1507 	struct nvmet_rdma_queue *queue;
1508 
1509 	nvmet_unregister_transport(&nvmet_rdma_ops);
1510 
1511 	flush_scheduled_work();
1512 
1513 	mutex_lock(&nvmet_rdma_queue_mutex);
1514 	while ((queue = list_first_entry_or_null(&nvmet_rdma_queue_list,
1515 			struct nvmet_rdma_queue, queue_list))) {
1516 		list_del_init(&queue->queue_list);
1517 
1518 		mutex_unlock(&nvmet_rdma_queue_mutex);
1519 		__nvmet_rdma_queue_disconnect(queue);
1520 		mutex_lock(&nvmet_rdma_queue_mutex);
1521 	}
1522 	mutex_unlock(&nvmet_rdma_queue_mutex);
1523 
1524 	flush_scheduled_work();
1525 	ida_destroy(&nvmet_rdma_queue_ida);
1526 }
1527 
1528 module_init(nvmet_rdma_init);
1529 module_exit(nvmet_rdma_exit);
1530 
1531 MODULE_LICENSE("GPL v2");
1532 MODULE_ALIAS("nvmet-transport-1"); /* 1 == NVMF_TRTYPE_RDMA */
1533