xref: /linux/drivers/infiniband/ulp/srp/ib_srp.c (revision 13e91fd076306f5d0cdfa14f53d69e37274723c4)
1 /*
2  * Copyright (c) 2005 Cisco Systems.  All rights reserved.
3  *
4  * This software is available to you under a choice of one of two
5  * licenses.  You may choose to be licensed under the terms of the GNU
6  * General Public License (GPL) Version 2, available from the file
7  * COPYING in the main directory of this source tree, or the
8  * OpenIB.org BSD license below:
9  *
10  *     Redistribution and use in source and binary forms, with or
11  *     without modification, are permitted provided that the following
12  *     conditions are met:
13  *
14  *      - Redistributions of source code must retain the above
15  *        copyright notice, this list of conditions and the following
16  *        disclaimer.
17  *
18  *      - Redistributions in binary form must reproduce the above
19  *        copyright notice, this list of conditions and the following
20  *        disclaimer in the documentation and/or other materials
21  *        provided with the distribution.
22  *
23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30  * SOFTWARE.
31  */
32 
33 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
34 
35 #include <linux/module.h>
36 #include <linux/hex.h>
37 #include <linux/init.h>
38 #include <linux/slab.h>
39 #include <linux/err.h>
40 #include <linux/string.h>
41 #include <linux/parser.h>
42 #include <linux/random.h>
43 #include <linux/jiffies.h>
44 #include <linux/lockdep.h>
45 #include <linux/inet.h>
46 #include <net/net_namespace.h>
47 #include <rdma/ib_cache.h>
48 
49 #include <linux/atomic.h>
50 
51 #include <scsi/scsi.h>
52 #include <scsi/scsi_device.h>
53 #include <scsi/scsi_dbg.h>
54 #include <scsi/scsi_tcq.h>
55 #include <scsi/srp.h>
56 #include <scsi/scsi_transport_srp.h>
57 
58 #include "ib_srp.h"
59 
60 #define DRV_NAME	"ib_srp"
61 #define PFX		DRV_NAME ": "
62 
63 MODULE_AUTHOR("Roland Dreier");
64 MODULE_DESCRIPTION("InfiniBand SCSI RDMA Protocol initiator");
65 MODULE_LICENSE("Dual BSD/GPL");
66 
67 static unsigned int srp_sg_tablesize;
68 static unsigned int cmd_sg_entries;
69 static unsigned int indirect_sg_entries;
70 static bool allow_ext_sg;
71 static bool register_always = true;
72 static bool never_register;
73 static int topspin_workarounds = 1;
74 
75 module_param(srp_sg_tablesize, uint, 0444);
76 MODULE_PARM_DESC(srp_sg_tablesize, "Deprecated name for cmd_sg_entries");
77 
78 module_param(cmd_sg_entries, uint, 0444);
79 MODULE_PARM_DESC(cmd_sg_entries,
80 		 "Default number of gather/scatter entries in the SRP command (default is 12, max 255)");
81 
82 module_param(indirect_sg_entries, uint, 0444);
83 MODULE_PARM_DESC(indirect_sg_entries,
84 		 "Default max number of gather/scatter entries (default is 12, max is " __stringify(SG_MAX_SEGMENTS) ")");
85 
86 module_param(allow_ext_sg, bool, 0444);
87 MODULE_PARM_DESC(allow_ext_sg,
88 		  "Default behavior when there are more than cmd_sg_entries S/G entries after mapping; fails the request when false (default false)");
89 
90 module_param(topspin_workarounds, int, 0444);
91 MODULE_PARM_DESC(topspin_workarounds,
92 		 "Enable workarounds for Topspin/Cisco SRP target bugs if != 0");
93 
94 module_param(register_always, bool, 0444);
95 MODULE_PARM_DESC(register_always,
96 		 "Use memory registration even for contiguous memory regions");
97 
98 module_param(never_register, bool, 0444);
99 MODULE_PARM_DESC(never_register, "Never register memory");
100 
101 static const struct kernel_param_ops srp_tmo_ops;
102 
103 static int srp_reconnect_delay = 10;
104 module_param_cb(reconnect_delay, &srp_tmo_ops, &srp_reconnect_delay,
105 		S_IRUGO | S_IWUSR);
106 MODULE_PARM_DESC(reconnect_delay, "Time between successive reconnect attempts");
107 
108 static int srp_fast_io_fail_tmo = 15;
109 module_param_cb(fast_io_fail_tmo, &srp_tmo_ops, &srp_fast_io_fail_tmo,
110 		S_IRUGO | S_IWUSR);
111 MODULE_PARM_DESC(fast_io_fail_tmo,
112 		 "Number of seconds between the observation of a transport"
113 		 " layer error and failing all I/O. \"off\" means that this"
114 		 " functionality is disabled.");
115 
116 static int srp_dev_loss_tmo = 600;
117 module_param_cb(dev_loss_tmo, &srp_tmo_ops, &srp_dev_loss_tmo,
118 		S_IRUGO | S_IWUSR);
119 MODULE_PARM_DESC(dev_loss_tmo,
120 		 "Maximum number of seconds that the SRP transport should"
121 		 " insulate transport layer errors. After this time has been"
122 		 " exceeded the SCSI host is removed. Should be"
123 		 " between 1 and " __stringify(SCSI_DEVICE_BLOCK_MAX_TIMEOUT)
124 		 " if fast_io_fail_tmo has not been set. \"off\" means that"
125 		 " this functionality is disabled.");
126 
127 static bool srp_use_imm_data = true;
128 module_param_named(use_imm_data, srp_use_imm_data, bool, 0644);
129 MODULE_PARM_DESC(use_imm_data,
130 		 "Whether or not to request permission to use immediate data during SRP login.");
131 
132 static unsigned int srp_max_imm_data = 8 * 1024;
133 module_param_named(max_imm_data, srp_max_imm_data, uint, 0644);
134 MODULE_PARM_DESC(max_imm_data, "Maximum immediate data size.");
135 
136 static unsigned ch_count;
137 module_param(ch_count, uint, 0444);
138 MODULE_PARM_DESC(ch_count,
139 		 "Number of RDMA channels to use for communication with an SRP target. Using more than one channel improves performance if the HCA supports multiple completion vectors. The default value is the minimum of four times the number of online CPU sockets and the number of completion vectors supported by the HCA.");
140 
141 static int srp_add_one(struct ib_device *device);
142 static void srp_remove_one(struct ib_device *device, void *client_data);
143 static void srp_rename_dev(struct ib_device *device, void *client_data);
144 static void srp_recv_done(struct ib_cq *cq, struct ib_wc *wc);
145 static void srp_handle_qp_err(struct ib_cq *cq, struct ib_wc *wc,
146 		const char *opname);
147 static int srp_ib_cm_handler(struct ib_cm_id *cm_id,
148 			     const struct ib_cm_event *event);
149 static int srp_rdma_cm_handler(struct rdma_cm_id *cm_id,
150 			       struct rdma_cm_event *event);
151 
152 static struct scsi_transport_template *ib_srp_transport_template;
153 static struct workqueue_struct *srp_remove_wq;
154 
155 static struct ib_client srp_client = {
156 	.name   = "srp",
157 	.add    = srp_add_one,
158 	.remove = srp_remove_one,
159 	.rename = srp_rename_dev
160 };
161 
162 static struct ib_sa_client srp_sa_client;
163 
164 static int srp_tmo_get(char *buffer, const struct kernel_param *kp)
165 {
166 	int tmo = *(int *)kp->arg;
167 
168 	if (tmo >= 0)
169 		return sysfs_emit(buffer, "%d\n", tmo);
170 	else
171 		return sysfs_emit(buffer, "off\n");
172 }
173 
174 static int srp_tmo_set(const char *val, const struct kernel_param *kp)
175 {
176 	int tmo, res;
177 
178 	res = srp_parse_tmo(&tmo, val);
179 	if (res)
180 		goto out;
181 
182 	if (kp->arg == &srp_reconnect_delay)
183 		res = srp_tmo_valid(tmo, srp_fast_io_fail_tmo,
184 				    srp_dev_loss_tmo);
185 	else if (kp->arg == &srp_fast_io_fail_tmo)
186 		res = srp_tmo_valid(srp_reconnect_delay, tmo, srp_dev_loss_tmo);
187 	else
188 		res = srp_tmo_valid(srp_reconnect_delay, srp_fast_io_fail_tmo,
189 				    tmo);
190 	if (res)
191 		goto out;
192 	*(int *)kp->arg = tmo;
193 
194 out:
195 	return res;
196 }
197 
198 static const struct kernel_param_ops srp_tmo_ops = {
199 	.get = srp_tmo_get,
200 	.set = srp_tmo_set,
201 };
202 
203 static inline struct srp_target_port *host_to_target(struct Scsi_Host *host)
204 {
205 	return (struct srp_target_port *) host->hostdata;
206 }
207 
208 static const char *srp_target_info(struct Scsi_Host *host)
209 {
210 	return host_to_target(host)->target_name;
211 }
212 
213 static int srp_target_is_topspin(struct srp_target_port *target)
214 {
215 	static const u8 topspin_oui[3] = { 0x00, 0x05, 0xad };
216 	static const u8 cisco_oui[3]   = { 0x00, 0x1b, 0x0d };
217 
218 	return topspin_workarounds &&
219 		(!memcmp(&target->ioc_guid, topspin_oui, sizeof topspin_oui) ||
220 		 !memcmp(&target->ioc_guid, cisco_oui, sizeof cisco_oui));
221 }
222 
223 static struct srp_iu *srp_alloc_iu(struct srp_host *host, size_t size,
224 				   gfp_t gfp_mask,
225 				   enum dma_data_direction direction)
226 {
227 	struct srp_iu *iu;
228 
229 	iu = kmalloc_obj(*iu, gfp_mask);
230 	if (!iu)
231 		goto out;
232 
233 	iu->buf = kzalloc(size, gfp_mask);
234 	if (!iu->buf)
235 		goto out_free_iu;
236 
237 	iu->dma = ib_dma_map_single(host->srp_dev->dev, iu->buf, size,
238 				    direction);
239 	if (ib_dma_mapping_error(host->srp_dev->dev, iu->dma))
240 		goto out_free_buf;
241 
242 	iu->size      = size;
243 	iu->direction = direction;
244 
245 	return iu;
246 
247 out_free_buf:
248 	kfree(iu->buf);
249 out_free_iu:
250 	kfree(iu);
251 out:
252 	return NULL;
253 }
254 
255 static void srp_free_iu(struct srp_host *host, struct srp_iu *iu)
256 {
257 	if (!iu)
258 		return;
259 
260 	ib_dma_unmap_single(host->srp_dev->dev, iu->dma, iu->size,
261 			    iu->direction);
262 	kfree(iu->buf);
263 	kfree(iu);
264 }
265 
266 static void srp_qp_event(struct ib_event *event, void *context)
267 {
268 	pr_debug("QP event %s (%d)\n",
269 		 ib_event_msg(event->event), event->event);
270 }
271 
272 static int srp_init_ib_qp(struct srp_target_port *target,
273 			  struct ib_qp *qp)
274 {
275 	struct ib_qp_attr *attr;
276 	int ret;
277 
278 	attr = kmalloc_obj(*attr);
279 	if (!attr)
280 		return -ENOMEM;
281 
282 	ret = ib_find_cached_pkey(target->srp_host->srp_dev->dev,
283 				  target->srp_host->port,
284 				  be16_to_cpu(target->ib_cm.pkey),
285 				  &attr->pkey_index);
286 	if (ret)
287 		goto out;
288 
289 	attr->qp_state        = IB_QPS_INIT;
290 	attr->qp_access_flags = (IB_ACCESS_REMOTE_READ |
291 				    IB_ACCESS_REMOTE_WRITE);
292 	attr->port_num        = target->srp_host->port;
293 
294 	ret = ib_modify_qp(qp, attr,
295 			   IB_QP_STATE		|
296 			   IB_QP_PKEY_INDEX	|
297 			   IB_QP_ACCESS_FLAGS	|
298 			   IB_QP_PORT);
299 
300 out:
301 	kfree(attr);
302 	return ret;
303 }
304 
305 static int srp_new_ib_cm_id(struct srp_rdma_ch *ch)
306 {
307 	struct srp_target_port *target = ch->target;
308 	struct ib_cm_id *new_cm_id;
309 
310 	new_cm_id = ib_create_cm_id(target->srp_host->srp_dev->dev,
311 				    srp_ib_cm_handler, ch);
312 	if (IS_ERR(new_cm_id))
313 		return PTR_ERR(new_cm_id);
314 
315 	if (ch->ib_cm.cm_id)
316 		ib_destroy_cm_id(ch->ib_cm.cm_id);
317 	ch->ib_cm.cm_id = new_cm_id;
318 	if (rdma_cap_opa_ah(target->srp_host->srp_dev->dev,
319 			    target->srp_host->port))
320 		ch->ib_cm.path.rec_type = SA_PATH_REC_TYPE_OPA;
321 	else
322 		ch->ib_cm.path.rec_type = SA_PATH_REC_TYPE_IB;
323 	ch->ib_cm.path.sgid = target->sgid;
324 	ch->ib_cm.path.dgid = target->ib_cm.orig_dgid;
325 	ch->ib_cm.path.pkey = target->ib_cm.pkey;
326 	ch->ib_cm.path.service_id = target->ib_cm.service_id;
327 
328 	return 0;
329 }
330 
331 static int srp_new_rdma_cm_id(struct srp_rdma_ch *ch)
332 {
333 	struct srp_target_port *target = ch->target;
334 	struct rdma_cm_id *new_cm_id;
335 	int ret;
336 
337 	new_cm_id = rdma_create_id(target->net, srp_rdma_cm_handler, ch,
338 				   RDMA_PS_TCP, IB_QPT_RC);
339 	if (IS_ERR(new_cm_id)) {
340 		ret = PTR_ERR(new_cm_id);
341 		new_cm_id = NULL;
342 		goto out;
343 	}
344 
345 	init_completion(&ch->done);
346 	ret = rdma_resolve_addr(new_cm_id, target->rdma_cm.src_specified ?
347 				&target->rdma_cm.src.sa : NULL,
348 				&target->rdma_cm.dst.sa,
349 				SRP_PATH_REC_TIMEOUT_MS);
350 	if (ret) {
351 		pr_err("No route available from %pISpsc to %pISpsc (%d)\n",
352 		       &target->rdma_cm.src, &target->rdma_cm.dst, ret);
353 		goto out;
354 	}
355 	ret = wait_for_completion_interruptible(&ch->done);
356 	if (ret < 0)
357 		goto out;
358 
359 	ret = ch->status;
360 	if (ret) {
361 		pr_err("Resolving address %pISpsc failed (%d)\n",
362 		       &target->rdma_cm.dst, ret);
363 		goto out;
364 	}
365 
366 	swap(ch->rdma_cm.cm_id, new_cm_id);
367 
368 out:
369 	if (new_cm_id)
370 		rdma_destroy_id(new_cm_id);
371 
372 	return ret;
373 }
374 
375 static int srp_new_cm_id(struct srp_rdma_ch *ch)
376 {
377 	struct srp_target_port *target = ch->target;
378 
379 	return target->using_rdma_cm ? srp_new_rdma_cm_id(ch) :
380 		srp_new_ib_cm_id(ch);
381 }
382 
383 /**
384  * srp_destroy_fr_pool() - free the resources owned by a pool
385  * @pool: Fast registration pool to be destroyed.
386  */
387 static void srp_destroy_fr_pool(struct srp_fr_pool *pool)
388 {
389 	int i;
390 	struct srp_fr_desc *d;
391 
392 	if (!pool)
393 		return;
394 
395 	for (i = 0, d = &pool->desc[0]; i < pool->size; i++, d++) {
396 		if (d->mr)
397 			ib_dereg_mr(d->mr);
398 	}
399 	kfree(pool);
400 }
401 
402 /**
403  * srp_create_fr_pool() - allocate and initialize a pool for fast registration
404  * @device:            IB device to allocate fast registration descriptors for.
405  * @pd:                Protection domain associated with the FR descriptors.
406  * @pool_size:         Number of descriptors to allocate.
407  * @max_page_list_len: Maximum fast registration work request page list length.
408  */
409 static struct srp_fr_pool *srp_create_fr_pool(struct ib_device *device,
410 					      struct ib_pd *pd, int pool_size,
411 					      int max_page_list_len)
412 {
413 	struct srp_fr_pool *pool;
414 	struct srp_fr_desc *d;
415 	struct ib_mr *mr;
416 	int i, ret = -EINVAL;
417 	enum ib_mr_type mr_type;
418 
419 	if (pool_size <= 0)
420 		goto err;
421 	ret = -ENOMEM;
422 	pool = kzalloc_flex(*pool, desc, pool_size);
423 	if (!pool)
424 		goto err;
425 	pool->size = pool_size;
426 	pool->max_page_list_len = max_page_list_len;
427 	spin_lock_init(&pool->lock);
428 	INIT_LIST_HEAD(&pool->free_list);
429 
430 	if (device->attrs.kernel_cap_flags & IBK_SG_GAPS_REG)
431 		mr_type = IB_MR_TYPE_SG_GAPS;
432 	else
433 		mr_type = IB_MR_TYPE_MEM_REG;
434 
435 	for (i = 0, d = &pool->desc[0]; i < pool->size; i++, d++) {
436 		mr = ib_alloc_mr(pd, mr_type, max_page_list_len);
437 		if (IS_ERR(mr)) {
438 			ret = PTR_ERR(mr);
439 			if (ret == -ENOMEM)
440 				pr_info("%s: ib_alloc_mr() failed. Try to reduce max_cmd_per_lun, max_sect or ch_count\n",
441 					dev_name(&device->dev));
442 			goto destroy_pool;
443 		}
444 		d->mr = mr;
445 		list_add_tail(&d->entry, &pool->free_list);
446 	}
447 
448 out:
449 	return pool;
450 
451 destroy_pool:
452 	srp_destroy_fr_pool(pool);
453 
454 err:
455 	pool = ERR_PTR(ret);
456 	goto out;
457 }
458 
459 /**
460  * srp_fr_pool_get() - obtain a descriptor suitable for fast registration
461  * @pool: Pool to obtain descriptor from.
462  */
463 static struct srp_fr_desc *srp_fr_pool_get(struct srp_fr_pool *pool)
464 {
465 	struct srp_fr_desc *d = NULL;
466 	unsigned long flags;
467 
468 	spin_lock_irqsave(&pool->lock, flags);
469 	if (!list_empty(&pool->free_list)) {
470 		d = list_first_entry(&pool->free_list, typeof(*d), entry);
471 		list_del(&d->entry);
472 	}
473 	spin_unlock_irqrestore(&pool->lock, flags);
474 
475 	return d;
476 }
477 
478 /**
479  * srp_fr_pool_put() - put an FR descriptor back in the free list
480  * @pool: Pool the descriptor was allocated from.
481  * @desc: Pointer to an array of fast registration descriptor pointers.
482  * @n:    Number of descriptors to put back.
483  *
484  * Note: The caller must already have queued an invalidation request for
485  * desc->mr->rkey before calling this function.
486  */
487 static void srp_fr_pool_put(struct srp_fr_pool *pool, struct srp_fr_desc **desc,
488 			    int n)
489 {
490 	unsigned long flags;
491 	int i;
492 
493 	spin_lock_irqsave(&pool->lock, flags);
494 	for (i = 0; i < n; i++)
495 		list_add(&desc[i]->entry, &pool->free_list);
496 	spin_unlock_irqrestore(&pool->lock, flags);
497 }
498 
499 static struct srp_fr_pool *srp_alloc_fr_pool(struct srp_target_port *target)
500 {
501 	struct srp_device *dev = target->srp_host->srp_dev;
502 
503 	return srp_create_fr_pool(dev->dev, dev->pd, target->mr_pool_size,
504 				  dev->max_pages_per_mr);
505 }
506 
507 /**
508  * srp_destroy_qp() - destroy an RDMA queue pair
509  * @ch: SRP RDMA channel.
510  *
511  * Drain the qp before destroying it.  This avoids that the receive
512  * completion handler can access the queue pair while it is
513  * being destroyed.
514  */
515 static void srp_destroy_qp(struct srp_rdma_ch *ch)
516 {
517 	spin_lock_irq(&ch->lock);
518 	ib_process_cq_direct(ch->send_cq, -1);
519 	spin_unlock_irq(&ch->lock);
520 
521 	ib_drain_qp(ch->qp);
522 	ib_destroy_qp(ch->qp);
523 }
524 
525 static int srp_create_ch_ib(struct srp_rdma_ch *ch)
526 {
527 	struct srp_target_port *target = ch->target;
528 	struct srp_device *dev = target->srp_host->srp_dev;
529 	const struct ib_device_attr *attr = &dev->dev->attrs;
530 	struct ib_qp_init_attr *init_attr;
531 	struct ib_cq *recv_cq, *send_cq;
532 	struct ib_qp *qp;
533 	struct srp_fr_pool *fr_pool = NULL;
534 	const int m = 1 + dev->use_fast_reg * target->mr_per_cmd * 2;
535 	int ret;
536 
537 	init_attr = kzalloc_obj(*init_attr);
538 	if (!init_attr)
539 		return -ENOMEM;
540 
541 	/* queue_size + 1 for ib_drain_rq() */
542 	recv_cq = ib_alloc_cq(dev->dev, ch, target->queue_size + 1,
543 				ch->comp_vector, IB_POLL_SOFTIRQ);
544 	if (IS_ERR(recv_cq)) {
545 		ret = PTR_ERR(recv_cq);
546 		goto err;
547 	}
548 
549 	send_cq = ib_alloc_cq(dev->dev, ch, m * target->queue_size,
550 				ch->comp_vector, IB_POLL_DIRECT);
551 	if (IS_ERR(send_cq)) {
552 		ret = PTR_ERR(send_cq);
553 		goto err_recv_cq;
554 	}
555 
556 	init_attr->event_handler       = srp_qp_event;
557 	init_attr->cap.max_send_wr     = m * target->queue_size;
558 	init_attr->cap.max_recv_wr     = target->queue_size + 1;
559 	init_attr->cap.max_recv_sge    = 1;
560 	init_attr->cap.max_send_sge    = min(SRP_MAX_SGE, attr->max_send_sge);
561 	init_attr->sq_sig_type         = IB_SIGNAL_REQ_WR;
562 	init_attr->qp_type             = IB_QPT_RC;
563 	init_attr->send_cq             = send_cq;
564 	init_attr->recv_cq             = recv_cq;
565 
566 	ch->max_imm_sge = min(init_attr->cap.max_send_sge - 1U, 255U);
567 
568 	if (target->using_rdma_cm) {
569 		ret = rdma_create_qp(ch->rdma_cm.cm_id, dev->pd, init_attr);
570 		qp = ch->rdma_cm.cm_id->qp;
571 	} else {
572 		qp = ib_create_qp(dev->pd, init_attr);
573 		if (!IS_ERR(qp)) {
574 			ret = srp_init_ib_qp(target, qp);
575 			if (ret)
576 				ib_destroy_qp(qp);
577 		} else {
578 			ret = PTR_ERR(qp);
579 		}
580 	}
581 	if (ret) {
582 		pr_err("QP creation failed for dev %s: %d\n",
583 		       dev_name(&dev->dev->dev), ret);
584 		goto err_send_cq;
585 	}
586 
587 	if (dev->use_fast_reg) {
588 		fr_pool = srp_alloc_fr_pool(target);
589 		if (IS_ERR(fr_pool)) {
590 			ret = PTR_ERR(fr_pool);
591 			shost_printk(KERN_WARNING, target->scsi_host, PFX
592 				     "FR pool allocation failed (%d)\n", ret);
593 			goto err_qp;
594 		}
595 	}
596 
597 	if (ch->qp)
598 		srp_destroy_qp(ch);
599 	if (ch->recv_cq)
600 		ib_free_cq(ch->recv_cq);
601 	if (ch->send_cq)
602 		ib_free_cq(ch->send_cq);
603 
604 	ch->qp = qp;
605 	ch->recv_cq = recv_cq;
606 	ch->send_cq = send_cq;
607 
608 	if (dev->use_fast_reg) {
609 		if (ch->fr_pool)
610 			srp_destroy_fr_pool(ch->fr_pool);
611 		ch->fr_pool = fr_pool;
612 	}
613 
614 	kfree(init_attr);
615 	return 0;
616 
617 err_qp:
618 	if (target->using_rdma_cm)
619 		rdma_destroy_qp(ch->rdma_cm.cm_id);
620 	else
621 		ib_destroy_qp(qp);
622 
623 err_send_cq:
624 	ib_free_cq(send_cq);
625 
626 err_recv_cq:
627 	ib_free_cq(recv_cq);
628 
629 err:
630 	kfree(init_attr);
631 	return ret;
632 }
633 
634 /*
635  * Note: this function may be called without srp_alloc_iu_bufs() having been
636  * invoked. Hence the ch->[rt]x_ring checks.
637  */
638 static void srp_free_ch_ib(struct srp_target_port *target,
639 			   struct srp_rdma_ch *ch)
640 {
641 	struct srp_device *dev = target->srp_host->srp_dev;
642 	int i;
643 
644 	if (!ch->target)
645 		return;
646 
647 	if (target->using_rdma_cm) {
648 		if (ch->rdma_cm.cm_id) {
649 			rdma_destroy_id(ch->rdma_cm.cm_id);
650 			ch->rdma_cm.cm_id = NULL;
651 		}
652 	} else {
653 		if (ch->ib_cm.cm_id) {
654 			ib_destroy_cm_id(ch->ib_cm.cm_id);
655 			ch->ib_cm.cm_id = NULL;
656 		}
657 	}
658 
659 	/* If srp_new_cm_id() succeeded but srp_create_ch_ib() not, return. */
660 	if (!ch->qp)
661 		return;
662 
663 	if (dev->use_fast_reg) {
664 		if (ch->fr_pool)
665 			srp_destroy_fr_pool(ch->fr_pool);
666 	}
667 
668 	srp_destroy_qp(ch);
669 	ib_free_cq(ch->send_cq);
670 	ib_free_cq(ch->recv_cq);
671 
672 	/*
673 	 * Avoid that the SCSI error handler tries to use this channel after
674 	 * it has been freed. The SCSI error handler can namely continue
675 	 * trying to perform recovery actions after scsi_remove_host()
676 	 * returned.
677 	 */
678 	ch->target = NULL;
679 
680 	ch->qp = NULL;
681 	ch->send_cq = ch->recv_cq = NULL;
682 
683 	if (ch->rx_ring) {
684 		for (i = 0; i < target->queue_size; ++i)
685 			srp_free_iu(target->srp_host, ch->rx_ring[i]);
686 		kfree(ch->rx_ring);
687 		ch->rx_ring = NULL;
688 	}
689 	if (ch->tx_ring) {
690 		for (i = 0; i < target->queue_size; ++i)
691 			srp_free_iu(target->srp_host, ch->tx_ring[i]);
692 		kfree(ch->tx_ring);
693 		ch->tx_ring = NULL;
694 	}
695 }
696 
697 static void srp_path_rec_completion(int status,
698 				    struct sa_path_rec *pathrec,
699 				    unsigned int num_paths, void *ch_ptr)
700 {
701 	struct srp_rdma_ch *ch = ch_ptr;
702 	struct srp_target_port *target = ch->target;
703 
704 	ch->status = status;
705 	if (status)
706 		shost_printk(KERN_ERR, target->scsi_host,
707 			     PFX "Got failed path rec status %d\n", status);
708 	else
709 		ch->ib_cm.path = *pathrec;
710 	complete(&ch->done);
711 }
712 
713 static int srp_ib_lookup_path(struct srp_rdma_ch *ch)
714 {
715 	struct srp_target_port *target = ch->target;
716 	int ret;
717 
718 	ch->ib_cm.path.numb_path = 1;
719 
720 	init_completion(&ch->done);
721 
722 	ch->ib_cm.path_query_id = ib_sa_path_rec_get(&srp_sa_client,
723 					       target->srp_host->srp_dev->dev,
724 					       target->srp_host->port,
725 					       &ch->ib_cm.path,
726 					       IB_SA_PATH_REC_SERVICE_ID |
727 					       IB_SA_PATH_REC_DGID	 |
728 					       IB_SA_PATH_REC_SGID	 |
729 					       IB_SA_PATH_REC_NUMB_PATH	 |
730 					       IB_SA_PATH_REC_PKEY,
731 					       SRP_PATH_REC_TIMEOUT_MS,
732 					       GFP_KERNEL,
733 					       srp_path_rec_completion,
734 					       ch, &ch->ib_cm.path_query);
735 	if (ch->ib_cm.path_query_id < 0)
736 		return ch->ib_cm.path_query_id;
737 
738 	ret = wait_for_completion_interruptible(&ch->done);
739 	if (ret < 0)
740 		return ret;
741 
742 	if (ch->status < 0)
743 		shost_printk(KERN_WARNING, target->scsi_host,
744 			     PFX "Path record query failed: sgid %pI6, dgid %pI6, pkey %#04x, service_id %#16llx\n",
745 			     ch->ib_cm.path.sgid.raw, ch->ib_cm.path.dgid.raw,
746 			     be16_to_cpu(target->ib_cm.pkey),
747 			     be64_to_cpu(target->ib_cm.service_id));
748 
749 	return ch->status;
750 }
751 
752 static int srp_rdma_lookup_path(struct srp_rdma_ch *ch)
753 {
754 	struct srp_target_port *target = ch->target;
755 	int ret;
756 
757 	init_completion(&ch->done);
758 
759 	ret = rdma_resolve_route(ch->rdma_cm.cm_id, SRP_PATH_REC_TIMEOUT_MS);
760 	if (ret)
761 		return ret;
762 
763 	wait_for_completion_interruptible(&ch->done);
764 
765 	if (ch->status != 0)
766 		shost_printk(KERN_WARNING, target->scsi_host,
767 			     PFX "Path resolution failed\n");
768 
769 	return ch->status;
770 }
771 
772 static int srp_lookup_path(struct srp_rdma_ch *ch)
773 {
774 	struct srp_target_port *target = ch->target;
775 
776 	return target->using_rdma_cm ? srp_rdma_lookup_path(ch) :
777 		srp_ib_lookup_path(ch);
778 }
779 
780 static u8 srp_get_subnet_timeout(struct srp_host *host)
781 {
782 	struct ib_port_attr attr;
783 	int ret;
784 	u8 subnet_timeout = 18;
785 
786 	ret = ib_query_port(host->srp_dev->dev, host->port, &attr);
787 	if (ret == 0)
788 		subnet_timeout = attr.subnet_timeout;
789 
790 	if (unlikely(subnet_timeout < 15))
791 		pr_warn("%s: subnet timeout %d may cause SRP login to fail.\n",
792 			dev_name(&host->srp_dev->dev->dev), subnet_timeout);
793 
794 	return subnet_timeout;
795 }
796 
797 static int srp_send_req(struct srp_rdma_ch *ch, uint32_t max_iu_len,
798 			bool multich)
799 {
800 	struct srp_target_port *target = ch->target;
801 	struct {
802 		struct rdma_conn_param	  rdma_param;
803 		struct srp_login_req_rdma rdma_req;
804 		struct ib_cm_req_param	  ib_param;
805 		struct srp_login_req	  ib_req;
806 	} *req = NULL;
807 	char *ipi, *tpi;
808 	int status;
809 
810 	req = kzalloc_obj(*req);
811 	if (!req)
812 		return -ENOMEM;
813 
814 	req->ib_param.flow_control = 1;
815 	req->ib_param.retry_count = target->tl_retry_count;
816 
817 	/*
818 	 * Pick some arbitrary defaults here; we could make these
819 	 * module parameters if anyone cared about setting them.
820 	 */
821 	req->ib_param.responder_resources = 4;
822 	req->ib_param.rnr_retry_count = 7;
823 	req->ib_param.max_cm_retries = 15;
824 
825 	req->ib_req.opcode = SRP_LOGIN_REQ;
826 	req->ib_req.tag = 0;
827 	req->ib_req.req_it_iu_len = cpu_to_be32(max_iu_len);
828 	req->ib_req.req_buf_fmt	= cpu_to_be16(SRP_BUF_FORMAT_DIRECT |
829 					      SRP_BUF_FORMAT_INDIRECT);
830 	req->ib_req.req_flags = (multich ? SRP_MULTICHAN_MULTI :
831 				 SRP_MULTICHAN_SINGLE);
832 	if (srp_use_imm_data) {
833 		req->ib_req.req_flags |= SRP_IMMED_REQUESTED;
834 		req->ib_req.imm_data_offset = cpu_to_be16(SRP_IMM_DATA_OFFSET);
835 	}
836 
837 	if (target->using_rdma_cm) {
838 		req->rdma_param.flow_control = req->ib_param.flow_control;
839 		req->rdma_param.responder_resources =
840 			req->ib_param.responder_resources;
841 		req->rdma_param.initiator_depth = req->ib_param.initiator_depth;
842 		req->rdma_param.retry_count = req->ib_param.retry_count;
843 		req->rdma_param.rnr_retry_count = req->ib_param.rnr_retry_count;
844 		req->rdma_param.private_data = &req->rdma_req;
845 		req->rdma_param.private_data_len = sizeof(req->rdma_req);
846 
847 		req->rdma_req.opcode = req->ib_req.opcode;
848 		req->rdma_req.tag = req->ib_req.tag;
849 		req->rdma_req.req_it_iu_len = req->ib_req.req_it_iu_len;
850 		req->rdma_req.req_buf_fmt = req->ib_req.req_buf_fmt;
851 		req->rdma_req.req_flags	= req->ib_req.req_flags;
852 		req->rdma_req.imm_data_offset = req->ib_req.imm_data_offset;
853 
854 		ipi = req->rdma_req.initiator_port_id;
855 		tpi = req->rdma_req.target_port_id;
856 	} else {
857 		u8 subnet_timeout;
858 
859 		subnet_timeout = srp_get_subnet_timeout(target->srp_host);
860 
861 		req->ib_param.primary_path = &ch->ib_cm.path;
862 		req->ib_param.alternate_path = NULL;
863 		req->ib_param.service_id = target->ib_cm.service_id;
864 		get_random_bytes(&req->ib_param.starting_psn, 4);
865 		req->ib_param.starting_psn &= 0xffffff;
866 		req->ib_param.qp_num = ch->qp->qp_num;
867 		req->ib_param.qp_type = ch->qp->qp_type;
868 		req->ib_param.local_cm_response_timeout = subnet_timeout + 2;
869 		req->ib_param.remote_cm_response_timeout = subnet_timeout + 2;
870 		req->ib_param.private_data = &req->ib_req;
871 		req->ib_param.private_data_len = sizeof(req->ib_req);
872 
873 		ipi = req->ib_req.initiator_port_id;
874 		tpi = req->ib_req.target_port_id;
875 	}
876 
877 	/*
878 	 * In the published SRP specification (draft rev. 16a), the
879 	 * port identifier format is 8 bytes of ID extension followed
880 	 * by 8 bytes of GUID.  Older drafts put the two halves in the
881 	 * opposite order, so that the GUID comes first.
882 	 *
883 	 * Targets conforming to these obsolete drafts can be
884 	 * recognized by the I/O Class they report.
885 	 */
886 	if (target->io_class == SRP_REV10_IB_IO_CLASS) {
887 		memcpy(ipi,     &target->sgid.global.interface_id, 8);
888 		memcpy(ipi + 8, &target->initiator_ext, 8);
889 		memcpy(tpi,     &target->ioc_guid, 8);
890 		memcpy(tpi + 8, &target->id_ext, 8);
891 	} else {
892 		memcpy(ipi,     &target->initiator_ext, 8);
893 		memcpy(ipi + 8, &target->sgid.global.interface_id, 8);
894 		memcpy(tpi,     &target->id_ext, 8);
895 		memcpy(tpi + 8, &target->ioc_guid, 8);
896 	}
897 
898 	/*
899 	 * Topspin/Cisco SRP targets will reject our login unless we
900 	 * zero out the first 8 bytes of our initiator port ID and set
901 	 * the second 8 bytes to the local node GUID.
902 	 */
903 	if (srp_target_is_topspin(target)) {
904 		shost_printk(KERN_DEBUG, target->scsi_host,
905 			     PFX "Topspin/Cisco initiator port ID workaround "
906 			     "activated for target GUID %016llx\n",
907 			     be64_to_cpu(target->ioc_guid));
908 		memset(ipi, 0, 8);
909 		memcpy(ipi + 8, &target->srp_host->srp_dev->dev->node_guid, 8);
910 	}
911 
912 	if (target->using_rdma_cm)
913 		status = rdma_connect(ch->rdma_cm.cm_id, &req->rdma_param);
914 	else
915 		status = ib_send_cm_req(ch->ib_cm.cm_id, &req->ib_param);
916 
917 	kfree(req);
918 
919 	return status;
920 }
921 
922 static bool srp_queue_remove_work(struct srp_target_port *target)
923 {
924 	bool changed = false;
925 
926 	spin_lock_irq(&target->lock);
927 	if (target->state != SRP_TARGET_REMOVED) {
928 		target->state = SRP_TARGET_REMOVED;
929 		changed = true;
930 	}
931 	spin_unlock_irq(&target->lock);
932 
933 	if (changed)
934 		queue_work(srp_remove_wq, &target->remove_work);
935 
936 	return changed;
937 }
938 
939 static void srp_disconnect_target(struct srp_target_port *target)
940 {
941 	struct srp_rdma_ch *ch;
942 	int i, ret;
943 
944 	/* XXX should send SRP_I_LOGOUT request */
945 
946 	for (i = 0; i < target->ch_count; i++) {
947 		ch = &target->ch[i];
948 		ch->connected = false;
949 		ret = 0;
950 		if (target->using_rdma_cm) {
951 			if (ch->rdma_cm.cm_id)
952 				rdma_disconnect(ch->rdma_cm.cm_id);
953 		} else {
954 			if (ch->ib_cm.cm_id)
955 				ret = ib_send_cm_dreq(ch->ib_cm.cm_id,
956 						      NULL, 0);
957 		}
958 		if (ret < 0) {
959 			shost_printk(KERN_DEBUG, target->scsi_host,
960 				     PFX "Sending CM DREQ failed\n");
961 		}
962 	}
963 }
964 
965 static int srp_exit_cmd_priv(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
966 {
967 	struct srp_target_port *target = host_to_target(shost);
968 	struct srp_device *dev = target->srp_host->srp_dev;
969 	struct ib_device *ibdev = dev->dev;
970 	struct srp_request *req = scsi_cmd_priv(cmd);
971 
972 	kfree(req->fr_list);
973 	if (req->indirect_dma_addr) {
974 		ib_dma_unmap_single(ibdev, req->indirect_dma_addr,
975 				    target->indirect_size,
976 				    DMA_TO_DEVICE);
977 	}
978 	kfree(req->indirect_desc);
979 
980 	return 0;
981 }
982 
983 static int srp_init_cmd_priv(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
984 {
985 	struct srp_target_port *target = host_to_target(shost);
986 	struct srp_device *srp_dev = target->srp_host->srp_dev;
987 	struct ib_device *ibdev = srp_dev->dev;
988 	struct srp_request *req = scsi_cmd_priv(cmd);
989 	dma_addr_t dma_addr;
990 	int ret = -ENOMEM;
991 
992 	if (srp_dev->use_fast_reg) {
993 		req->fr_list = kmalloc_array(target->mr_per_cmd, sizeof(void *),
994 					GFP_KERNEL);
995 		if (!req->fr_list)
996 			goto out;
997 	}
998 	req->indirect_desc = kmalloc(target->indirect_size, GFP_KERNEL);
999 	if (!req->indirect_desc)
1000 		goto out;
1001 
1002 	dma_addr = ib_dma_map_single(ibdev, req->indirect_desc,
1003 				     target->indirect_size,
1004 				     DMA_TO_DEVICE);
1005 	if (ib_dma_mapping_error(ibdev, dma_addr)) {
1006 		srp_exit_cmd_priv(shost, cmd);
1007 		goto out;
1008 	}
1009 
1010 	req->indirect_dma_addr = dma_addr;
1011 	ret = 0;
1012 
1013 out:
1014 	return ret;
1015 }
1016 
1017 /**
1018  * srp_del_scsi_host_attr() - Remove attributes defined in the host template.
1019  * @shost: SCSI host whose attributes to remove from sysfs.
1020  *
1021  * Note: Any attributes defined in the host template and that did not exist
1022  * before invocation of this function will be ignored.
1023  */
1024 static void srp_del_scsi_host_attr(struct Scsi_Host *shost)
1025 {
1026 	const struct attribute_group **g;
1027 	struct attribute **attr;
1028 
1029 	for (g = shost->hostt->shost_groups; *g; ++g) {
1030 		for (attr = (*g)->attrs; *attr; ++attr) {
1031 			struct device_attribute *dev_attr =
1032 				container_of(*attr, typeof(*dev_attr), attr);
1033 
1034 			device_remove_file(&shost->shost_dev, dev_attr);
1035 		}
1036 	}
1037 }
1038 
1039 static void srp_remove_target(struct srp_target_port *target)
1040 {
1041 	struct srp_rdma_ch *ch;
1042 	int i;
1043 
1044 	WARN_ON_ONCE(target->state != SRP_TARGET_REMOVED);
1045 
1046 	srp_del_scsi_host_attr(target->scsi_host);
1047 	srp_rport_get(target->rport);
1048 	srp_remove_host(target->scsi_host);
1049 	scsi_remove_host(target->scsi_host);
1050 	srp_stop_rport_timers(target->rport);
1051 	srp_disconnect_target(target);
1052 	kobj_ns_drop(KOBJ_NS_TYPE_NET, to_ns_common(target->net));
1053 	for (i = 0; i < target->ch_count; i++) {
1054 		ch = &target->ch[i];
1055 		srp_free_ch_ib(target, ch);
1056 	}
1057 	cancel_work_sync(&target->tl_err_work);
1058 	srp_rport_put(target->rport);
1059 	kfree(target->ch);
1060 	target->ch = NULL;
1061 
1062 	spin_lock(&target->srp_host->target_lock);
1063 	list_del(&target->list);
1064 	spin_unlock(&target->srp_host->target_lock);
1065 
1066 	scsi_host_put(target->scsi_host);
1067 }
1068 
1069 static void srp_remove_work(struct work_struct *work)
1070 {
1071 	struct srp_target_port *target =
1072 		container_of(work, struct srp_target_port, remove_work);
1073 
1074 	WARN_ON_ONCE(target->state != SRP_TARGET_REMOVED);
1075 
1076 	srp_remove_target(target);
1077 }
1078 
1079 static void srp_rport_delete(struct srp_rport *rport)
1080 {
1081 	struct srp_target_port *target = rport->lld_data;
1082 
1083 	srp_queue_remove_work(target);
1084 }
1085 
1086 /**
1087  * srp_connected_ch() - number of connected channels
1088  * @target: SRP target port.
1089  */
1090 static int srp_connected_ch(struct srp_target_port *target)
1091 {
1092 	int i, c = 0;
1093 
1094 	for (i = 0; i < target->ch_count; i++)
1095 		c += target->ch[i].connected;
1096 
1097 	return c;
1098 }
1099 
1100 static int srp_connect_ch(struct srp_rdma_ch *ch, uint32_t max_iu_len,
1101 			  bool multich)
1102 {
1103 	struct srp_target_port *target = ch->target;
1104 	int ret;
1105 
1106 	WARN_ON_ONCE(!multich && srp_connected_ch(target) > 0);
1107 
1108 	ret = srp_lookup_path(ch);
1109 	if (ret)
1110 		goto out;
1111 
1112 	while (1) {
1113 		init_completion(&ch->done);
1114 		ret = srp_send_req(ch, max_iu_len, multich);
1115 		if (ret)
1116 			goto out;
1117 		ret = wait_for_completion_interruptible(&ch->done);
1118 		if (ret < 0)
1119 			goto out;
1120 
1121 		/*
1122 		 * The CM event handling code will set status to
1123 		 * SRP_PORT_REDIRECT if we get a port redirect REJ
1124 		 * back, or SRP_DLID_REDIRECT if we get a lid/qp
1125 		 * redirect REJ back.
1126 		 */
1127 		ret = ch->status;
1128 		switch (ret) {
1129 		case 0:
1130 			ch->connected = true;
1131 			goto out;
1132 
1133 		case SRP_PORT_REDIRECT:
1134 			ret = srp_lookup_path(ch);
1135 			if (ret)
1136 				goto out;
1137 			break;
1138 
1139 		case SRP_DLID_REDIRECT:
1140 			break;
1141 
1142 		case SRP_STALE_CONN:
1143 			shost_printk(KERN_ERR, target->scsi_host, PFX
1144 				     "giving up on stale connection\n");
1145 			ret = -ECONNRESET;
1146 			goto out;
1147 
1148 		default:
1149 			goto out;
1150 		}
1151 	}
1152 
1153 out:
1154 	return ret <= 0 ? ret : -ENODEV;
1155 }
1156 
1157 static void srp_inv_rkey_err_done(struct ib_cq *cq, struct ib_wc *wc)
1158 {
1159 	srp_handle_qp_err(cq, wc, "INV RKEY");
1160 }
1161 
1162 static int srp_inv_rkey(struct srp_request *req, struct srp_rdma_ch *ch,
1163 		u32 rkey)
1164 {
1165 	struct ib_send_wr wr = {
1166 		.opcode		    = IB_WR_LOCAL_INV,
1167 		.next		    = NULL,
1168 		.num_sge	    = 0,
1169 		.send_flags	    = 0,
1170 		.ex.invalidate_rkey = rkey,
1171 	};
1172 
1173 	wr.wr_cqe = &req->reg_cqe;
1174 	req->reg_cqe.done = srp_inv_rkey_err_done;
1175 	return ib_post_send(ch->qp, &wr, NULL);
1176 }
1177 
1178 static void srp_unmap_data(struct scsi_cmnd *scmnd,
1179 			   struct srp_rdma_ch *ch,
1180 			   struct srp_request *req)
1181 {
1182 	struct srp_target_port *target = ch->target;
1183 	struct srp_device *dev = target->srp_host->srp_dev;
1184 	struct ib_device *ibdev = dev->dev;
1185 	int i, res;
1186 
1187 	if (!scsi_sglist(scmnd) ||
1188 	    (scmnd->sc_data_direction != DMA_TO_DEVICE &&
1189 	     scmnd->sc_data_direction != DMA_FROM_DEVICE))
1190 		return;
1191 
1192 	if (dev->use_fast_reg) {
1193 		struct srp_fr_desc **pfr;
1194 
1195 		for (i = req->nmdesc, pfr = req->fr_list; i > 0; i--, pfr++) {
1196 			res = srp_inv_rkey(req, ch, (*pfr)->mr->rkey);
1197 			if (res < 0) {
1198 				shost_printk(KERN_ERR, target->scsi_host, PFX
1199 				  "Queueing INV WR for rkey %#x failed (%d)\n",
1200 				  (*pfr)->mr->rkey, res);
1201 				queue_work(system_long_wq,
1202 					   &target->tl_err_work);
1203 			}
1204 		}
1205 		if (req->nmdesc)
1206 			srp_fr_pool_put(ch->fr_pool, req->fr_list,
1207 					req->nmdesc);
1208 	}
1209 
1210 	ib_dma_unmap_sg(ibdev, scsi_sglist(scmnd), scsi_sg_count(scmnd),
1211 			scmnd->sc_data_direction);
1212 }
1213 
1214 /**
1215  * srp_claim_req - Take ownership of the scmnd associated with a request.
1216  * @ch: SRP RDMA channel.
1217  * @req: SRP request.
1218  * @sdev: If not NULL, only take ownership for this SCSI device.
1219  * @scmnd: If NULL, take ownership of @req->scmnd. If not NULL, only take
1220  *         ownership of @req->scmnd if it equals @scmnd.
1221  *
1222  * Return value:
1223  * Either NULL or a pointer to the SCSI command the caller became owner of.
1224  */
1225 static struct scsi_cmnd *srp_claim_req(struct srp_rdma_ch *ch,
1226 				       struct srp_request *req,
1227 				       struct scsi_device *sdev,
1228 				       struct scsi_cmnd *scmnd)
1229 {
1230 	unsigned long flags;
1231 
1232 	spin_lock_irqsave(&ch->lock, flags);
1233 	if (req->scmnd &&
1234 	    (!sdev || req->scmnd->device == sdev) &&
1235 	    (!scmnd || req->scmnd == scmnd)) {
1236 		scmnd = req->scmnd;
1237 		req->scmnd = NULL;
1238 	} else {
1239 		scmnd = NULL;
1240 	}
1241 	spin_unlock_irqrestore(&ch->lock, flags);
1242 
1243 	return scmnd;
1244 }
1245 
1246 /**
1247  * srp_free_req() - Unmap data and adjust ch->req_lim.
1248  * @ch:     SRP RDMA channel.
1249  * @req:    Request to be freed.
1250  * @scmnd:  SCSI command associated with @req.
1251  * @req_lim_delta: Amount to be added to @target->req_lim.
1252  */
1253 static void srp_free_req(struct srp_rdma_ch *ch, struct srp_request *req,
1254 			 struct scsi_cmnd *scmnd, s32 req_lim_delta)
1255 {
1256 	unsigned long flags;
1257 
1258 	srp_unmap_data(scmnd, ch, req);
1259 
1260 	spin_lock_irqsave(&ch->lock, flags);
1261 	ch->req_lim += req_lim_delta;
1262 	spin_unlock_irqrestore(&ch->lock, flags);
1263 }
1264 
1265 static void srp_finish_req(struct srp_rdma_ch *ch, struct srp_request *req,
1266 			   struct scsi_device *sdev, int result)
1267 {
1268 	struct scsi_cmnd *scmnd = srp_claim_req(ch, req, sdev, NULL);
1269 
1270 	if (scmnd) {
1271 		srp_free_req(ch, req, scmnd, 0);
1272 		scmnd->result = result;
1273 		scsi_done(scmnd);
1274 	}
1275 }
1276 
1277 struct srp_terminate_context {
1278 	struct srp_target_port *srp_target;
1279 	int scsi_result;
1280 };
1281 
1282 static bool srp_terminate_cmd(struct scsi_cmnd *scmnd, void *context_ptr)
1283 {
1284 	struct srp_terminate_context *context = context_ptr;
1285 	struct srp_target_port *target = context->srp_target;
1286 	u32 tag = blk_mq_unique_tag(scsi_cmd_to_rq(scmnd));
1287 	struct srp_rdma_ch *ch = &target->ch[blk_mq_unique_tag_to_hwq(tag)];
1288 	struct srp_request *req = scsi_cmd_priv(scmnd);
1289 
1290 	srp_finish_req(ch, req, NULL, context->scsi_result);
1291 
1292 	return true;
1293 }
1294 
1295 static void srp_terminate_io(struct srp_rport *rport)
1296 {
1297 	struct srp_target_port *target = rport->lld_data;
1298 	struct srp_terminate_context context = { .srp_target = target,
1299 		.scsi_result = DID_TRANSPORT_FAILFAST << 16 };
1300 
1301 	scsi_host_busy_iter(target->scsi_host, srp_terminate_cmd, &context);
1302 }
1303 
1304 /* Calculate maximum initiator to target information unit length. */
1305 static uint32_t srp_max_it_iu_len(int cmd_sg_cnt, bool use_imm_data,
1306 				  uint32_t max_it_iu_size)
1307 {
1308 	uint32_t max_iu_len = sizeof(struct srp_cmd) + SRP_MAX_ADD_CDB_LEN +
1309 		sizeof(struct srp_indirect_buf) +
1310 		cmd_sg_cnt * sizeof(struct srp_direct_buf);
1311 
1312 	if (use_imm_data)
1313 		max_iu_len = max(max_iu_len, SRP_IMM_DATA_OFFSET +
1314 				 srp_max_imm_data);
1315 
1316 	if (max_it_iu_size)
1317 		max_iu_len = min(max_iu_len, max_it_iu_size);
1318 
1319 	pr_debug("max_iu_len = %d\n", max_iu_len);
1320 
1321 	return max_iu_len;
1322 }
1323 
1324 /*
1325  * It is up to the caller to ensure that srp_rport_reconnect() calls are
1326  * serialized and that no concurrent srp_queuecommand(), srp_abort(),
1327  * srp_reset_device() or srp_reset_host() calls will occur while this function
1328  * is in progress. One way to realize that is not to call this function
1329  * directly but to call srp_reconnect_rport() instead since that last function
1330  * serializes calls of this function via rport->mutex and also blocks
1331  * srp_queuecommand() calls before invoking this function.
1332  */
1333 static int srp_rport_reconnect(struct srp_rport *rport)
1334 {
1335 	struct srp_target_port *target = rport->lld_data;
1336 	struct srp_rdma_ch *ch;
1337 	uint32_t max_iu_len = srp_max_it_iu_len(target->cmd_sg_cnt,
1338 						srp_use_imm_data,
1339 						target->max_it_iu_size);
1340 	int i, j, ret = 0;
1341 	bool multich = false;
1342 
1343 	srp_disconnect_target(target);
1344 
1345 	if (target->state == SRP_TARGET_SCANNING)
1346 		return -ENODEV;
1347 
1348 	/*
1349 	 * Now get a new local CM ID so that we avoid confusing the target in
1350 	 * case things are really fouled up. Doing so also ensures that all CM
1351 	 * callbacks will have finished before a new QP is allocated.
1352 	 */
1353 	for (i = 0; i < target->ch_count; i++) {
1354 		ch = &target->ch[i];
1355 		ret += srp_new_cm_id(ch);
1356 	}
1357 	{
1358 		struct srp_terminate_context context = {
1359 			.srp_target = target, .scsi_result = DID_RESET << 16};
1360 
1361 		scsi_host_busy_iter(target->scsi_host, srp_terminate_cmd,
1362 				    &context);
1363 	}
1364 	for (i = 0; i < target->ch_count; i++) {
1365 		ch = &target->ch[i];
1366 		/*
1367 		 * Whether or not creating a new CM ID succeeded, create a new
1368 		 * QP. This guarantees that all completion callback function
1369 		 * invocations have finished before request resetting starts.
1370 		 */
1371 		ret += srp_create_ch_ib(ch);
1372 
1373 		INIT_LIST_HEAD(&ch->free_tx);
1374 		for (j = 0; j < target->queue_size; ++j)
1375 			list_add(&ch->tx_ring[j]->list, &ch->free_tx);
1376 	}
1377 
1378 	target->qp_in_error = false;
1379 
1380 	for (i = 0; i < target->ch_count; i++) {
1381 		ch = &target->ch[i];
1382 		if (ret)
1383 			break;
1384 		ret = srp_connect_ch(ch, max_iu_len, multich);
1385 		multich = true;
1386 	}
1387 
1388 	if (ret == 0)
1389 		shost_printk(KERN_INFO, target->scsi_host,
1390 			     PFX "reconnect succeeded\n");
1391 
1392 	return ret;
1393 }
1394 
1395 static void srp_map_desc(struct srp_map_state *state, dma_addr_t dma_addr,
1396 			 unsigned int dma_len, u32 rkey)
1397 {
1398 	struct srp_direct_buf *desc = state->desc;
1399 
1400 	WARN_ON_ONCE(!dma_len);
1401 
1402 	desc->va = cpu_to_be64(dma_addr);
1403 	desc->key = cpu_to_be32(rkey);
1404 	desc->len = cpu_to_be32(dma_len);
1405 
1406 	state->total_len += dma_len;
1407 	state->desc++;
1408 	state->ndesc++;
1409 }
1410 
1411 static void srp_reg_mr_err_done(struct ib_cq *cq, struct ib_wc *wc)
1412 {
1413 	srp_handle_qp_err(cq, wc, "FAST REG");
1414 }
1415 
1416 /*
1417  * Map up to sg_nents elements of state->sg where *sg_offset_p is the offset
1418  * where to start in the first element. If sg_offset_p != NULL then
1419  * *sg_offset_p is updated to the offset in state->sg[retval] of the first
1420  * byte that has not yet been mapped.
1421  */
1422 static int srp_map_finish_fr(struct srp_map_state *state,
1423 			     struct srp_request *req,
1424 			     struct srp_rdma_ch *ch, int sg_nents,
1425 			     unsigned int *sg_offset_p)
1426 {
1427 	struct srp_target_port *target = ch->target;
1428 	struct srp_device *dev = target->srp_host->srp_dev;
1429 	struct ib_reg_wr wr;
1430 	struct srp_fr_desc *desc;
1431 	u32 rkey;
1432 	int n, err;
1433 
1434 	if (state->fr.next >= state->fr.end) {
1435 		shost_printk(KERN_ERR, ch->target->scsi_host,
1436 			     PFX "Out of MRs (mr_per_cmd = %d)\n",
1437 			     ch->target->mr_per_cmd);
1438 		return -ENOMEM;
1439 	}
1440 
1441 	WARN_ON_ONCE(!dev->use_fast_reg);
1442 
1443 	if (sg_nents == 1 && target->global_rkey) {
1444 		unsigned int sg_offset = sg_offset_p ? *sg_offset_p : 0;
1445 
1446 		srp_map_desc(state, sg_dma_address(state->sg) + sg_offset,
1447 			     sg_dma_len(state->sg) - sg_offset,
1448 			     target->global_rkey);
1449 		if (sg_offset_p)
1450 			*sg_offset_p = 0;
1451 		return 1;
1452 	}
1453 
1454 	desc = srp_fr_pool_get(ch->fr_pool);
1455 	if (!desc)
1456 		return -ENOMEM;
1457 
1458 	rkey = ib_inc_rkey(desc->mr->rkey);
1459 	ib_update_fast_reg_key(desc->mr, rkey);
1460 
1461 	n = ib_map_mr_sg(desc->mr, state->sg, sg_nents, sg_offset_p,
1462 			 dev->mr_page_size);
1463 	if (unlikely(n < 0)) {
1464 		srp_fr_pool_put(ch->fr_pool, &desc, 1);
1465 		pr_debug("%s: ib_map_mr_sg(%d, %d) returned %d.\n",
1466 			 dev_name(&req->scmnd->device->sdev_gendev), sg_nents,
1467 			 sg_offset_p ? *sg_offset_p : -1, n);
1468 		return n;
1469 	}
1470 
1471 	WARN_ON_ONCE(desc->mr->length == 0);
1472 
1473 	req->reg_cqe.done = srp_reg_mr_err_done;
1474 
1475 	wr.wr.next = NULL;
1476 	wr.wr.opcode = IB_WR_REG_MR;
1477 	wr.wr.wr_cqe = &req->reg_cqe;
1478 	wr.wr.num_sge = 0;
1479 	wr.wr.send_flags = 0;
1480 	wr.mr = desc->mr;
1481 	wr.key = desc->mr->rkey;
1482 	wr.access = (IB_ACCESS_LOCAL_WRITE |
1483 		     IB_ACCESS_REMOTE_READ |
1484 		     IB_ACCESS_REMOTE_WRITE);
1485 
1486 	*state->fr.next++ = desc;
1487 	state->nmdesc++;
1488 
1489 	srp_map_desc(state, desc->mr->iova,
1490 		     desc->mr->length, desc->mr->rkey);
1491 
1492 	err = ib_post_send(ch->qp, &wr.wr, NULL);
1493 	if (unlikely(err)) {
1494 		WARN_ON_ONCE(err == -ENOMEM);
1495 		return err;
1496 	}
1497 
1498 	return n;
1499 }
1500 
1501 static int srp_map_sg_fr(struct srp_map_state *state, struct srp_rdma_ch *ch,
1502 			 struct srp_request *req, struct scatterlist *scat,
1503 			 int count)
1504 {
1505 	unsigned int sg_offset = 0;
1506 
1507 	state->fr.next = req->fr_list;
1508 	state->fr.end = req->fr_list + ch->target->mr_per_cmd;
1509 	state->sg = scat;
1510 
1511 	if (count == 0)
1512 		return 0;
1513 
1514 	while (count) {
1515 		int i, n;
1516 
1517 		n = srp_map_finish_fr(state, req, ch, count, &sg_offset);
1518 		if (unlikely(n < 0))
1519 			return n;
1520 
1521 		count -= n;
1522 		for (i = 0; i < n; i++)
1523 			state->sg = sg_next(state->sg);
1524 	}
1525 
1526 	return 0;
1527 }
1528 
1529 static int srp_map_sg_dma(struct srp_map_state *state, struct srp_rdma_ch *ch,
1530 			  struct srp_request *req, struct scatterlist *scat,
1531 			  int count)
1532 {
1533 	struct srp_target_port *target = ch->target;
1534 	struct scatterlist *sg;
1535 	int i;
1536 
1537 	for_each_sg(scat, sg, count, i) {
1538 		srp_map_desc(state, sg_dma_address(sg), sg_dma_len(sg),
1539 			     target->global_rkey);
1540 	}
1541 
1542 	return 0;
1543 }
1544 
1545 /*
1546  * Register the indirect data buffer descriptor with the HCA.
1547  *
1548  * Note: since the indirect data buffer descriptor has been allocated with
1549  * kmalloc() it is guaranteed that this buffer is a physically contiguous
1550  * memory buffer.
1551  */
1552 static int srp_map_idb(struct srp_rdma_ch *ch, struct srp_request *req,
1553 		       void **next_mr, void **end_mr, u32 idb_len,
1554 		       __be32 *idb_rkey)
1555 {
1556 	struct srp_target_port *target = ch->target;
1557 	struct srp_device *dev = target->srp_host->srp_dev;
1558 	struct srp_map_state state;
1559 	struct srp_direct_buf idb_desc;
1560 	struct scatterlist idb_sg[1];
1561 	int ret;
1562 
1563 	memset(&state, 0, sizeof(state));
1564 	memset(&idb_desc, 0, sizeof(idb_desc));
1565 	state.gen.next = next_mr;
1566 	state.gen.end = end_mr;
1567 	state.desc = &idb_desc;
1568 	state.base_dma_addr = req->indirect_dma_addr;
1569 	state.dma_len = idb_len;
1570 
1571 	if (dev->use_fast_reg) {
1572 		state.sg = idb_sg;
1573 		sg_init_one(idb_sg, req->indirect_desc, idb_len);
1574 		idb_sg->dma_address = req->indirect_dma_addr; /* hack! */
1575 #ifdef CONFIG_NEED_SG_DMA_LENGTH
1576 		idb_sg->dma_length = idb_sg->length;	      /* hack^2 */
1577 #endif
1578 		ret = srp_map_finish_fr(&state, req, ch, 1, NULL);
1579 		if (ret < 0)
1580 			return ret;
1581 		WARN_ON_ONCE(ret < 1);
1582 	} else {
1583 		return -EINVAL;
1584 	}
1585 
1586 	*idb_rkey = idb_desc.key;
1587 
1588 	return 0;
1589 }
1590 
1591 static void srp_check_mapping(struct srp_map_state *state,
1592 			      struct srp_rdma_ch *ch, struct srp_request *req,
1593 			      struct scatterlist *scat, int count)
1594 {
1595 	struct srp_device *dev = ch->target->srp_host->srp_dev;
1596 	struct srp_fr_desc **pfr;
1597 	u64 desc_len = 0, mr_len = 0;
1598 	int i;
1599 
1600 	for (i = 0; i < state->ndesc; i++)
1601 		desc_len += be32_to_cpu(req->indirect_desc[i].len);
1602 	if (dev->use_fast_reg)
1603 		for (i = 0, pfr = req->fr_list; i < state->nmdesc; i++, pfr++)
1604 			mr_len += (*pfr)->mr->length;
1605 	if (desc_len != scsi_bufflen(req->scmnd) ||
1606 	    mr_len > scsi_bufflen(req->scmnd))
1607 		pr_err("Inconsistent: scsi len %d <> desc len %lld <> mr len %lld; ndesc %d; nmdesc = %d\n",
1608 		       scsi_bufflen(req->scmnd), desc_len, mr_len,
1609 		       state->ndesc, state->nmdesc);
1610 }
1611 
1612 /**
1613  * srp_map_data() - map SCSI data buffer onto an SRP request
1614  * @scmnd: SCSI command to map
1615  * @ch: SRP RDMA channel
1616  * @req: SRP request
1617  *
1618  * Returns the length in bytes of the SRP_CMD IU or a negative value if
1619  * mapping failed. The size of any immediate data is not included in the
1620  * return value.
1621  */
1622 static int srp_map_data(struct scsi_cmnd *scmnd, struct srp_rdma_ch *ch,
1623 			struct srp_request *req)
1624 {
1625 	struct srp_target_port *target = ch->target;
1626 	struct scatterlist *scat, *sg;
1627 	struct srp_cmd *cmd = req->cmd->buf;
1628 	int i, len, nents, count, ret;
1629 	struct srp_device *dev;
1630 	struct ib_device *ibdev;
1631 	struct srp_map_state state;
1632 	struct srp_indirect_buf *indirect_hdr;
1633 	u64 data_len;
1634 	u32 idb_len, table_len;
1635 	__be32 idb_rkey;
1636 	u8 fmt;
1637 
1638 	req->cmd->num_sge = 1;
1639 
1640 	if (!scsi_sglist(scmnd) || scmnd->sc_data_direction == DMA_NONE)
1641 		return sizeof(struct srp_cmd) + cmd->add_cdb_len;
1642 
1643 	if (scmnd->sc_data_direction != DMA_FROM_DEVICE &&
1644 	    scmnd->sc_data_direction != DMA_TO_DEVICE) {
1645 		shost_printk(KERN_WARNING, target->scsi_host,
1646 			     PFX "Unhandled data direction %d\n",
1647 			     scmnd->sc_data_direction);
1648 		return -EINVAL;
1649 	}
1650 
1651 	nents = scsi_sg_count(scmnd);
1652 	scat  = scsi_sglist(scmnd);
1653 	data_len = scsi_bufflen(scmnd);
1654 
1655 	dev = target->srp_host->srp_dev;
1656 	ibdev = dev->dev;
1657 
1658 	count = ib_dma_map_sg(ibdev, scat, nents, scmnd->sc_data_direction);
1659 	if (unlikely(count == 0))
1660 		return -EIO;
1661 
1662 	if (ch->use_imm_data &&
1663 	    count <= ch->max_imm_sge &&
1664 	    SRP_IMM_DATA_OFFSET + data_len <= ch->max_it_iu_len &&
1665 	    scmnd->sc_data_direction == DMA_TO_DEVICE) {
1666 		struct srp_imm_buf *buf;
1667 		struct ib_sge *sge = &req->cmd->sge[1];
1668 
1669 		fmt = SRP_DATA_DESC_IMM;
1670 		len = SRP_IMM_DATA_OFFSET;
1671 		req->nmdesc = 0;
1672 		buf = (void *)cmd->add_data + cmd->add_cdb_len;
1673 		buf->len = cpu_to_be32(data_len);
1674 		WARN_ON_ONCE((void *)(buf + 1) > (void *)cmd + len);
1675 		for_each_sg(scat, sg, count, i) {
1676 			sge[i].addr   = sg_dma_address(sg);
1677 			sge[i].length = sg_dma_len(sg);
1678 			sge[i].lkey   = target->lkey;
1679 		}
1680 		req->cmd->num_sge += count;
1681 		goto map_complete;
1682 	}
1683 
1684 	fmt = SRP_DATA_DESC_DIRECT;
1685 	len = sizeof(struct srp_cmd) + cmd->add_cdb_len +
1686 		sizeof(struct srp_direct_buf);
1687 
1688 	if (count == 1 && target->global_rkey) {
1689 		/*
1690 		 * The midlayer only generated a single gather/scatter
1691 		 * entry, or DMA mapping coalesced everything to a
1692 		 * single entry.  So a direct descriptor along with
1693 		 * the DMA MR suffices.
1694 		 */
1695 		struct srp_direct_buf *buf;
1696 
1697 		buf = (void *)cmd->add_data + cmd->add_cdb_len;
1698 		buf->va  = cpu_to_be64(sg_dma_address(scat));
1699 		buf->key = cpu_to_be32(target->global_rkey);
1700 		buf->len = cpu_to_be32(sg_dma_len(scat));
1701 
1702 		req->nmdesc = 0;
1703 		goto map_complete;
1704 	}
1705 
1706 	/*
1707 	 * We have more than one scatter/gather entry, so build our indirect
1708 	 * descriptor table, trying to merge as many entries as we can.
1709 	 */
1710 	indirect_hdr = (void *)cmd->add_data + cmd->add_cdb_len;
1711 
1712 	ib_dma_sync_single_for_cpu(ibdev, req->indirect_dma_addr,
1713 				   target->indirect_size, DMA_TO_DEVICE);
1714 
1715 	memset(&state, 0, sizeof(state));
1716 	state.desc = req->indirect_desc;
1717 	if (dev->use_fast_reg)
1718 		ret = srp_map_sg_fr(&state, ch, req, scat, count);
1719 	else
1720 		ret = srp_map_sg_dma(&state, ch, req, scat, count);
1721 	req->nmdesc = state.nmdesc;
1722 	if (ret < 0)
1723 		goto unmap;
1724 
1725 	{
1726 		DEFINE_DYNAMIC_DEBUG_METADATA(ddm,
1727 			"Memory mapping consistency check");
1728 		if (DYNAMIC_DEBUG_BRANCH(ddm))
1729 			srp_check_mapping(&state, ch, req, scat, count);
1730 	}
1731 
1732 	/* We've mapped the request, now pull as much of the indirect
1733 	 * descriptor table as we can into the command buffer. If this
1734 	 * target is not using an external indirect table, we are
1735 	 * guaranteed to fit into the command, as the SCSI layer won't
1736 	 * give us more S/G entries than we allow.
1737 	 */
1738 	if (state.ndesc == 1) {
1739 		/*
1740 		 * Memory registration collapsed the sg-list into one entry,
1741 		 * so use a direct descriptor.
1742 		 */
1743 		struct srp_direct_buf *buf;
1744 
1745 		buf = (void *)cmd->add_data + cmd->add_cdb_len;
1746 		*buf = req->indirect_desc[0];
1747 		goto map_complete;
1748 	}
1749 
1750 	if (unlikely(target->cmd_sg_cnt < state.ndesc &&
1751 						!target->allow_ext_sg)) {
1752 		shost_printk(KERN_ERR, target->scsi_host,
1753 			     "Could not fit S/G list into SRP_CMD\n");
1754 		ret = -EIO;
1755 		goto unmap;
1756 	}
1757 
1758 	count = min(state.ndesc, target->cmd_sg_cnt);
1759 	table_len = state.ndesc * sizeof (struct srp_direct_buf);
1760 	idb_len = sizeof(struct srp_indirect_buf) + table_len;
1761 
1762 	fmt = SRP_DATA_DESC_INDIRECT;
1763 	len = sizeof(struct srp_cmd) + cmd->add_cdb_len +
1764 		sizeof(struct srp_indirect_buf);
1765 	len += count * sizeof (struct srp_direct_buf);
1766 
1767 	memcpy(indirect_hdr->desc_list, req->indirect_desc,
1768 	       count * sizeof (struct srp_direct_buf));
1769 
1770 	if (!target->global_rkey) {
1771 		ret = srp_map_idb(ch, req, state.gen.next, state.gen.end,
1772 				  idb_len, &idb_rkey);
1773 		if (ret < 0)
1774 			goto unmap;
1775 		req->nmdesc++;
1776 	} else {
1777 		idb_rkey = cpu_to_be32(target->global_rkey);
1778 	}
1779 
1780 	indirect_hdr->table_desc.va = cpu_to_be64(req->indirect_dma_addr);
1781 	indirect_hdr->table_desc.key = idb_rkey;
1782 	indirect_hdr->table_desc.len = cpu_to_be32(table_len);
1783 	indirect_hdr->len = cpu_to_be32(state.total_len);
1784 
1785 	if (scmnd->sc_data_direction == DMA_TO_DEVICE)
1786 		cmd->data_out_desc_cnt = count;
1787 	else
1788 		cmd->data_in_desc_cnt = count;
1789 
1790 	ib_dma_sync_single_for_device(ibdev, req->indirect_dma_addr, table_len,
1791 				      DMA_TO_DEVICE);
1792 
1793 map_complete:
1794 	if (scmnd->sc_data_direction == DMA_TO_DEVICE)
1795 		cmd->buf_fmt = fmt << 4;
1796 	else
1797 		cmd->buf_fmt = fmt;
1798 
1799 	return len;
1800 
1801 unmap:
1802 	srp_unmap_data(scmnd, ch, req);
1803 	if (ret == -ENOMEM && req->nmdesc >= target->mr_pool_size)
1804 		ret = -E2BIG;
1805 	return ret;
1806 }
1807 
1808 /*
1809  * Return an IU and possible credit to the free pool
1810  */
1811 static void srp_put_tx_iu(struct srp_rdma_ch *ch, struct srp_iu *iu,
1812 			  enum srp_iu_type iu_type)
1813 {
1814 	unsigned long flags;
1815 
1816 	spin_lock_irqsave(&ch->lock, flags);
1817 	list_add(&iu->list, &ch->free_tx);
1818 	if (iu_type != SRP_IU_RSP)
1819 		++ch->req_lim;
1820 	spin_unlock_irqrestore(&ch->lock, flags);
1821 }
1822 
1823 /*
1824  * Must be called with ch->lock held to protect req_lim and free_tx.
1825  * If IU is not sent, it must be returned using srp_put_tx_iu().
1826  *
1827  * Note:
1828  * An upper limit for the number of allocated information units for each
1829  * request type is:
1830  * - SRP_IU_CMD: SRP_CMD_SQ_SIZE, since the SCSI mid-layer never queues
1831  *   more than Scsi_Host.can_queue requests.
1832  * - SRP_IU_TSK_MGMT: SRP_TSK_MGMT_SQ_SIZE.
1833  * - SRP_IU_RSP: 1, since a conforming SRP target never sends more than
1834  *   one unanswered SRP request to an initiator.
1835  */
1836 static struct srp_iu *__srp_get_tx_iu(struct srp_rdma_ch *ch,
1837 				      enum srp_iu_type iu_type)
1838 {
1839 	struct srp_target_port *target = ch->target;
1840 	s32 rsv = (iu_type == SRP_IU_TSK_MGMT) ? 0 : SRP_TSK_MGMT_SQ_SIZE;
1841 	struct srp_iu *iu;
1842 
1843 	lockdep_assert_held(&ch->lock);
1844 
1845 	ib_process_cq_direct(ch->send_cq, -1);
1846 
1847 	if (list_empty(&ch->free_tx))
1848 		return NULL;
1849 
1850 	/* Initiator responses to target requests do not consume credits */
1851 	if (iu_type != SRP_IU_RSP) {
1852 		if (ch->req_lim <= rsv) {
1853 			++target->zero_req_lim;
1854 			return NULL;
1855 		}
1856 
1857 		--ch->req_lim;
1858 	}
1859 
1860 	iu = list_first_entry(&ch->free_tx, struct srp_iu, list);
1861 	list_del(&iu->list);
1862 	return iu;
1863 }
1864 
1865 /*
1866  * Note: if this function is called from inside ib_drain_sq() then it will
1867  * be called without ch->lock being held. If ib_drain_sq() dequeues a WQE
1868  * with status IB_WC_SUCCESS then that's a bug.
1869  */
1870 static void srp_send_done(struct ib_cq *cq, struct ib_wc *wc)
1871 {
1872 	struct srp_iu *iu = container_of(wc->wr_cqe, struct srp_iu, cqe);
1873 	struct srp_rdma_ch *ch = cq->cq_context;
1874 
1875 	if (unlikely(wc->status != IB_WC_SUCCESS)) {
1876 		srp_handle_qp_err(cq, wc, "SEND");
1877 		return;
1878 	}
1879 
1880 	lockdep_assert_held(&ch->lock);
1881 
1882 	list_add(&iu->list, &ch->free_tx);
1883 }
1884 
1885 /**
1886  * srp_post_send() - send an SRP information unit
1887  * @ch: RDMA channel over which to send the information unit.
1888  * @iu: Information unit to send.
1889  * @len: Length of the information unit excluding immediate data.
1890  */
1891 static int srp_post_send(struct srp_rdma_ch *ch, struct srp_iu *iu, int len)
1892 {
1893 	struct srp_target_port *target = ch->target;
1894 	struct ib_send_wr wr;
1895 
1896 	if (WARN_ON_ONCE(iu->num_sge > SRP_MAX_SGE))
1897 		return -EINVAL;
1898 
1899 	iu->sge[0].addr   = iu->dma;
1900 	iu->sge[0].length = len;
1901 	iu->sge[0].lkey   = target->lkey;
1902 
1903 	iu->cqe.done = srp_send_done;
1904 
1905 	wr.next       = NULL;
1906 	wr.wr_cqe     = &iu->cqe;
1907 	wr.sg_list    = &iu->sge[0];
1908 	wr.num_sge    = iu->num_sge;
1909 	wr.opcode     = IB_WR_SEND;
1910 	wr.send_flags = IB_SEND_SIGNALED;
1911 
1912 	return ib_post_send(ch->qp, &wr, NULL);
1913 }
1914 
1915 static int srp_post_recv(struct srp_rdma_ch *ch, struct srp_iu *iu)
1916 {
1917 	struct srp_target_port *target = ch->target;
1918 	struct ib_recv_wr wr;
1919 	struct ib_sge list;
1920 
1921 	list.addr   = iu->dma;
1922 	list.length = iu->size;
1923 	list.lkey   = target->lkey;
1924 
1925 	iu->cqe.done = srp_recv_done;
1926 
1927 	wr.next     = NULL;
1928 	wr.wr_cqe   = &iu->cqe;
1929 	wr.sg_list  = &list;
1930 	wr.num_sge  = 1;
1931 
1932 	return ib_post_recv(ch->qp, &wr, NULL);
1933 }
1934 
1935 static void srp_process_rsp(struct srp_rdma_ch *ch, struct srp_rsp *rsp,
1936 			    u32 byte_len)
1937 {
1938 	struct srp_target_port *target = ch->target;
1939 	struct srp_request *req;
1940 	struct scsi_cmnd *scmnd;
1941 	unsigned long flags;
1942 
1943 	if (unlikely(rsp->tag & SRP_TAG_TSK_MGMT)) {
1944 		spin_lock_irqsave(&ch->lock, flags);
1945 		ch->req_lim += be32_to_cpu(rsp->req_lim_delta);
1946 		if (rsp->tag == ch->tsk_mgmt_tag) {
1947 			ch->tsk_mgmt_status = -1;
1948 			if (be32_to_cpu(rsp->resp_data_len) >= 4)
1949 				ch->tsk_mgmt_status = rsp->data[3];
1950 			complete(&ch->tsk_mgmt_done);
1951 		} else {
1952 			shost_printk(KERN_ERR, target->scsi_host,
1953 				     "Received tsk mgmt response too late for tag %#llx\n",
1954 				     rsp->tag);
1955 		}
1956 		spin_unlock_irqrestore(&ch->lock, flags);
1957 	} else {
1958 		scmnd = scsi_host_find_tag(target->scsi_host, rsp->tag);
1959 		if (scmnd) {
1960 			req = scsi_cmd_priv(scmnd);
1961 			scmnd = srp_claim_req(ch, req, NULL, scmnd);
1962 		}
1963 		if (!scmnd) {
1964 			shost_printk(KERN_ERR, target->scsi_host,
1965 				     "Null scmnd for RSP w/tag %#016llx received on ch %td / QP %#x\n",
1966 				     rsp->tag, ch - target->ch, ch->qp->qp_num);
1967 
1968 			spin_lock_irqsave(&ch->lock, flags);
1969 			ch->req_lim += be32_to_cpu(rsp->req_lim_delta);
1970 			spin_unlock_irqrestore(&ch->lock, flags);
1971 
1972 			return;
1973 		}
1974 		scmnd->result = rsp->status;
1975 
1976 		if (rsp->flags & SRP_RSP_FLAG_SNSVALID) {
1977 			u32 resp_len = be32_to_cpu(rsp->resp_data_len);
1978 			u32 sense_len = be32_to_cpu(rsp->sense_data_len);
1979 
1980 			/*
1981 			 * The sense data starts resp_data_len bytes past the
1982 			 * response data area; both lengths come from the
1983 			 * target-controlled response.  Copy the sense data
1984 			 * only if it has not been truncated, that is, only if
1985 			 * the full sense region fits within the bytes actually
1986 			 * received.  Otherwise the copy source would run past
1987 			 * the receive buffer (sized to the target-chosen
1988 			 * max_ti_iu_len), reading out of bounds.
1989 			 */
1990 			if (sizeof(*rsp) + (u64)resp_len + sense_len <= byte_len)
1991 				memcpy(scmnd->sense_buffer,
1992 				       rsp->data + resp_len,
1993 				       min(sense_len, SCSI_SENSE_BUFFERSIZE));
1994 			else
1995 				shost_printk(KERN_ERR, target->scsi_host,
1996 					     "dropping truncated sense data (resp_data_len %u sense_data_len %u, %u bytes received)\n",
1997 					     resp_len, sense_len, byte_len);
1998 		}
1999 
2000 		if (unlikely(rsp->flags & SRP_RSP_FLAG_DIUNDER))
2001 			scsi_set_resid(scmnd, be32_to_cpu(rsp->data_in_res_cnt));
2002 		else if (unlikely(rsp->flags & SRP_RSP_FLAG_DOUNDER))
2003 			scsi_set_resid(scmnd, be32_to_cpu(rsp->data_out_res_cnt));
2004 
2005 		srp_free_req(ch, req, scmnd,
2006 			     be32_to_cpu(rsp->req_lim_delta));
2007 
2008 		scsi_done(scmnd);
2009 	}
2010 }
2011 
2012 static int srp_response_common(struct srp_rdma_ch *ch, s32 req_delta,
2013 			       void *rsp, int len)
2014 {
2015 	struct srp_target_port *target = ch->target;
2016 	struct ib_device *dev = target->srp_host->srp_dev->dev;
2017 	unsigned long flags;
2018 	struct srp_iu *iu;
2019 	int err;
2020 
2021 	spin_lock_irqsave(&ch->lock, flags);
2022 	ch->req_lim += req_delta;
2023 	iu = __srp_get_tx_iu(ch, SRP_IU_RSP);
2024 	spin_unlock_irqrestore(&ch->lock, flags);
2025 
2026 	if (!iu) {
2027 		shost_printk(KERN_ERR, target->scsi_host, PFX
2028 			     "no IU available to send response\n");
2029 		return 1;
2030 	}
2031 
2032 	iu->num_sge = 1;
2033 	ib_dma_sync_single_for_cpu(dev, iu->dma, len, DMA_TO_DEVICE);
2034 	memcpy(iu->buf, rsp, len);
2035 	ib_dma_sync_single_for_device(dev, iu->dma, len, DMA_TO_DEVICE);
2036 
2037 	err = srp_post_send(ch, iu, len);
2038 	if (err) {
2039 		shost_printk(KERN_ERR, target->scsi_host, PFX
2040 			     "unable to post response: %d\n", err);
2041 		srp_put_tx_iu(ch, iu, SRP_IU_RSP);
2042 	}
2043 
2044 	return err;
2045 }
2046 
2047 static void srp_process_cred_req(struct srp_rdma_ch *ch,
2048 				 struct srp_cred_req *req)
2049 {
2050 	struct srp_cred_rsp rsp = {
2051 		.opcode = SRP_CRED_RSP,
2052 		.tag = req->tag,
2053 	};
2054 	s32 delta = be32_to_cpu(req->req_lim_delta);
2055 
2056 	if (srp_response_common(ch, delta, &rsp, sizeof(rsp)))
2057 		shost_printk(KERN_ERR, ch->target->scsi_host, PFX
2058 			     "problems processing SRP_CRED_REQ\n");
2059 }
2060 
2061 static void srp_process_aer_req(struct srp_rdma_ch *ch,
2062 				struct srp_aer_req *req)
2063 {
2064 	struct srp_target_port *target = ch->target;
2065 	struct srp_aer_rsp rsp = {
2066 		.opcode = SRP_AER_RSP,
2067 		.tag = req->tag,
2068 	};
2069 	s32 delta = be32_to_cpu(req->req_lim_delta);
2070 
2071 	shost_printk(KERN_ERR, target->scsi_host, PFX
2072 		     "ignoring AER for LUN %llu\n", scsilun_to_int(&req->lun));
2073 
2074 	if (srp_response_common(ch, delta, &rsp, sizeof(rsp)))
2075 		shost_printk(KERN_ERR, target->scsi_host, PFX
2076 			     "problems processing SRP_AER_REQ\n");
2077 }
2078 
2079 static void srp_recv_done(struct ib_cq *cq, struct ib_wc *wc)
2080 {
2081 	struct srp_iu *iu = container_of(wc->wr_cqe, struct srp_iu, cqe);
2082 	struct srp_rdma_ch *ch = cq->cq_context;
2083 	struct srp_target_port *target = ch->target;
2084 	struct ib_device *dev = target->srp_host->srp_dev->dev;
2085 	int res;
2086 	u8 opcode;
2087 
2088 	if (unlikely(wc->status != IB_WC_SUCCESS)) {
2089 		srp_handle_qp_err(cq, wc, "RECV");
2090 		return;
2091 	}
2092 
2093 	ib_dma_sync_single_for_cpu(dev, iu->dma, ch->max_ti_iu_len,
2094 				   DMA_FROM_DEVICE);
2095 
2096 	opcode = *(u8 *) iu->buf;
2097 
2098 	if (0) {
2099 		shost_printk(KERN_ERR, target->scsi_host,
2100 			     PFX "recv completion, opcode 0x%02x\n", opcode);
2101 		print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 8, 1,
2102 			       iu->buf, wc->byte_len, true);
2103 	}
2104 
2105 	switch (opcode) {
2106 	case SRP_RSP:
2107 		srp_process_rsp(ch, iu->buf, wc->byte_len);
2108 		break;
2109 
2110 	case SRP_CRED_REQ:
2111 		srp_process_cred_req(ch, iu->buf);
2112 		break;
2113 
2114 	case SRP_AER_REQ:
2115 		srp_process_aer_req(ch, iu->buf);
2116 		break;
2117 
2118 	case SRP_T_LOGOUT:
2119 		/* XXX Handle target logout */
2120 		shost_printk(KERN_WARNING, target->scsi_host,
2121 			     PFX "Got target logout request\n");
2122 		break;
2123 
2124 	default:
2125 		shost_printk(KERN_WARNING, target->scsi_host,
2126 			     PFX "Unhandled SRP opcode 0x%02x\n", opcode);
2127 		break;
2128 	}
2129 
2130 	ib_dma_sync_single_for_device(dev, iu->dma, ch->max_ti_iu_len,
2131 				      DMA_FROM_DEVICE);
2132 
2133 	res = srp_post_recv(ch, iu);
2134 	if (res != 0)
2135 		shost_printk(KERN_ERR, target->scsi_host,
2136 			     PFX "Recv failed with error code %d\n", res);
2137 }
2138 
2139 /**
2140  * srp_tl_err_work() - handle a transport layer error
2141  * @work: Work structure embedded in an SRP target port.
2142  *
2143  * Note: This function may get invoked before the rport has been created,
2144  * hence the target->rport test.
2145  */
2146 static void srp_tl_err_work(struct work_struct *work)
2147 {
2148 	struct srp_target_port *target;
2149 
2150 	target = container_of(work, struct srp_target_port, tl_err_work);
2151 	if (target->rport)
2152 		srp_start_tl_fail_timers(target->rport);
2153 }
2154 
2155 static void srp_handle_qp_err(struct ib_cq *cq, struct ib_wc *wc,
2156 		const char *opname)
2157 {
2158 	struct srp_rdma_ch *ch = cq->cq_context;
2159 	struct srp_target_port *target = ch->target;
2160 
2161 	if (ch->connected && !target->qp_in_error) {
2162 		shost_printk(KERN_ERR, target->scsi_host,
2163 			     PFX "failed %s status %s (%d) for CQE %p\n",
2164 			     opname, ib_wc_status_msg(wc->status), wc->status,
2165 			     wc->wr_cqe);
2166 		queue_work(system_long_wq, &target->tl_err_work);
2167 	}
2168 	target->qp_in_error = true;
2169 }
2170 
2171 static enum scsi_qc_status srp_queuecommand(struct Scsi_Host *shost,
2172 					    struct scsi_cmnd *scmnd)
2173 {
2174 	struct request *rq = scsi_cmd_to_rq(scmnd);
2175 	struct srp_target_port *target = host_to_target(shost);
2176 	struct srp_rdma_ch *ch;
2177 	struct srp_request *req = scsi_cmd_priv(scmnd);
2178 	struct srp_iu *iu;
2179 	struct srp_cmd *cmd;
2180 	struct ib_device *dev;
2181 	unsigned long flags;
2182 	u32 tag;
2183 	int len, ret;
2184 
2185 	scmnd->result = srp_chkready(target->rport);
2186 	if (unlikely(scmnd->result))
2187 		goto err;
2188 
2189 	WARN_ON_ONCE(rq->tag < 0);
2190 	tag = blk_mq_unique_tag(rq);
2191 	ch = &target->ch[blk_mq_unique_tag_to_hwq(tag)];
2192 
2193 	spin_lock_irqsave(&ch->lock, flags);
2194 	iu = __srp_get_tx_iu(ch, SRP_IU_CMD);
2195 	spin_unlock_irqrestore(&ch->lock, flags);
2196 
2197 	if (!iu)
2198 		goto err;
2199 
2200 	dev = target->srp_host->srp_dev->dev;
2201 	ib_dma_sync_single_for_cpu(dev, iu->dma, ch->max_it_iu_len,
2202 				   DMA_TO_DEVICE);
2203 
2204 	cmd = iu->buf;
2205 	memset(cmd, 0, sizeof *cmd);
2206 
2207 	cmd->opcode = SRP_CMD;
2208 	int_to_scsilun(scmnd->device->lun, &cmd->lun);
2209 	cmd->tag    = tag;
2210 	memcpy(cmd->cdb, scmnd->cmnd, scmnd->cmd_len);
2211 	if (unlikely(scmnd->cmd_len > sizeof(cmd->cdb))) {
2212 		cmd->add_cdb_len = round_up(scmnd->cmd_len - sizeof(cmd->cdb),
2213 					    4);
2214 		if (WARN_ON_ONCE(cmd->add_cdb_len > SRP_MAX_ADD_CDB_LEN))
2215 			goto err_iu;
2216 	}
2217 
2218 	req->scmnd    = scmnd;
2219 	req->cmd      = iu;
2220 
2221 	len = srp_map_data(scmnd, ch, req);
2222 	if (len < 0) {
2223 		shost_printk(KERN_ERR, target->scsi_host,
2224 			     PFX "Failed to map data (%d)\n", len);
2225 		/*
2226 		 * If we ran out of memory descriptors (-ENOMEM) because an
2227 		 * application is queuing many requests with more than
2228 		 * max_pages_per_mr sg-list elements, tell the SCSI mid-layer
2229 		 * to reduce queue depth temporarily.
2230 		 */
2231 		scmnd->result = len == -ENOMEM ?
2232 			DID_OK << 16 | SAM_STAT_TASK_SET_FULL : DID_ERROR << 16;
2233 		goto err_iu;
2234 	}
2235 
2236 	ib_dma_sync_single_for_device(dev, iu->dma, ch->max_it_iu_len,
2237 				      DMA_TO_DEVICE);
2238 
2239 	if (srp_post_send(ch, iu, len)) {
2240 		shost_printk(KERN_ERR, target->scsi_host, PFX "Send failed\n");
2241 		scmnd->result = DID_ERROR << 16;
2242 		goto err_unmap;
2243 	}
2244 
2245 	return 0;
2246 
2247 err_unmap:
2248 	srp_unmap_data(scmnd, ch, req);
2249 
2250 err_iu:
2251 	srp_put_tx_iu(ch, iu, SRP_IU_CMD);
2252 
2253 	/*
2254 	 * Avoid that the loops that iterate over the request ring can
2255 	 * encounter a dangling SCSI command pointer.
2256 	 */
2257 	req->scmnd = NULL;
2258 
2259 err:
2260 	if (scmnd->result) {
2261 		scsi_done(scmnd);
2262 		ret = 0;
2263 	} else {
2264 		ret = SCSI_MLQUEUE_HOST_BUSY;
2265 	}
2266 
2267 	return ret;
2268 }
2269 
2270 /*
2271  * Note: the resources allocated in this function are freed in
2272  * srp_free_ch_ib().
2273  */
2274 static int srp_alloc_iu_bufs(struct srp_rdma_ch *ch)
2275 {
2276 	struct srp_target_port *target = ch->target;
2277 	int i;
2278 
2279 	ch->rx_ring = kzalloc_objs(*ch->rx_ring, target->queue_size);
2280 	if (!ch->rx_ring)
2281 		goto err_no_ring;
2282 	ch->tx_ring = kzalloc_objs(*ch->tx_ring, target->queue_size);
2283 	if (!ch->tx_ring)
2284 		goto err_no_ring;
2285 
2286 	for (i = 0; i < target->queue_size; ++i) {
2287 		ch->rx_ring[i] = srp_alloc_iu(target->srp_host,
2288 					      ch->max_ti_iu_len,
2289 					      GFP_KERNEL, DMA_FROM_DEVICE);
2290 		if (!ch->rx_ring[i])
2291 			goto err;
2292 	}
2293 
2294 	for (i = 0; i < target->queue_size; ++i) {
2295 		ch->tx_ring[i] = srp_alloc_iu(target->srp_host,
2296 					      ch->max_it_iu_len,
2297 					      GFP_KERNEL, DMA_TO_DEVICE);
2298 		if (!ch->tx_ring[i])
2299 			goto err;
2300 
2301 		list_add(&ch->tx_ring[i]->list, &ch->free_tx);
2302 	}
2303 
2304 	return 0;
2305 
2306 err:
2307 	for (i = 0; i < target->queue_size; ++i) {
2308 		srp_free_iu(target->srp_host, ch->rx_ring[i]);
2309 		srp_free_iu(target->srp_host, ch->tx_ring[i]);
2310 	}
2311 
2312 
2313 err_no_ring:
2314 	kfree(ch->tx_ring);
2315 	ch->tx_ring = NULL;
2316 	kfree(ch->rx_ring);
2317 	ch->rx_ring = NULL;
2318 
2319 	return -ENOMEM;
2320 }
2321 
2322 static uint32_t srp_compute_rq_tmo(struct ib_qp_attr *qp_attr, int attr_mask)
2323 {
2324 	uint64_t T_tr_ns, max_compl_time_ms;
2325 	uint32_t rq_tmo_jiffies;
2326 
2327 	/*
2328 	 * According to section 11.2.4.2 in the IBTA spec (Modify Queue Pair,
2329 	 * table 91), both the QP timeout and the retry count have to be set
2330 	 * for RC QP's during the RTR to RTS transition.
2331 	 */
2332 	WARN_ON_ONCE((attr_mask & (IB_QP_TIMEOUT | IB_QP_RETRY_CNT)) !=
2333 		     (IB_QP_TIMEOUT | IB_QP_RETRY_CNT));
2334 
2335 	/*
2336 	 * Set target->rq_tmo_jiffies to one second more than the largest time
2337 	 * it can take before an error completion is generated. See also
2338 	 * C9-140..142 in the IBTA spec for more information about how to
2339 	 * convert the QP Local ACK Timeout value to nanoseconds.
2340 	 */
2341 	T_tr_ns = 4096 * (1ULL << qp_attr->timeout);
2342 	max_compl_time_ms = qp_attr->retry_cnt * 4 * T_tr_ns;
2343 	do_div(max_compl_time_ms, NSEC_PER_MSEC);
2344 	rq_tmo_jiffies = msecs_to_jiffies(max_compl_time_ms + 1000);
2345 
2346 	return rq_tmo_jiffies;
2347 }
2348 
2349 static void srp_cm_rep_handler(struct ib_cm_id *cm_id,
2350 			       const struct srp_login_rsp *lrsp,
2351 			       struct srp_rdma_ch *ch)
2352 {
2353 	struct srp_target_port *target = ch->target;
2354 	struct ib_qp_attr *qp_attr = NULL;
2355 	int attr_mask = 0;
2356 	int ret = 0;
2357 	int i;
2358 
2359 	if (lrsp->opcode == SRP_LOGIN_RSP) {
2360 		ch->max_ti_iu_len = be32_to_cpu(lrsp->max_ti_iu_len);
2361 		ch->req_lim       = be32_to_cpu(lrsp->req_lim_delta);
2362 		ch->use_imm_data  = srp_use_imm_data &&
2363 			(lrsp->rsp_flags & SRP_LOGIN_RSP_IMMED_SUPP);
2364 		ch->max_it_iu_len = srp_max_it_iu_len(target->cmd_sg_cnt,
2365 						      ch->use_imm_data,
2366 						      target->max_it_iu_size);
2367 		WARN_ON_ONCE(ch->max_it_iu_len >
2368 			     be32_to_cpu(lrsp->max_it_iu_len));
2369 
2370 		if (ch->use_imm_data)
2371 			shost_printk(KERN_DEBUG, target->scsi_host,
2372 				     PFX "using immediate data\n");
2373 
2374 		/*
2375 		 * Reserve credits for task management so we don't
2376 		 * bounce requests back to the SCSI mid-layer.
2377 		 */
2378 		target->scsi_host->can_queue
2379 			= min(ch->req_lim - SRP_TSK_MGMT_SQ_SIZE,
2380 			      target->scsi_host->can_queue);
2381 		target->scsi_host->cmd_per_lun
2382 			= min_t(int, target->scsi_host->can_queue,
2383 				target->scsi_host->cmd_per_lun);
2384 	} else {
2385 		shost_printk(KERN_WARNING, target->scsi_host,
2386 			     PFX "Unhandled RSP opcode %#x\n", lrsp->opcode);
2387 		ret = -ECONNRESET;
2388 		goto error;
2389 	}
2390 
2391 	if (!ch->rx_ring) {
2392 		ret = srp_alloc_iu_bufs(ch);
2393 		if (ret)
2394 			goto error;
2395 	}
2396 
2397 	for (i = 0; i < target->queue_size; i++) {
2398 		struct srp_iu *iu = ch->rx_ring[i];
2399 
2400 		ret = srp_post_recv(ch, iu);
2401 		if (ret)
2402 			goto error;
2403 	}
2404 
2405 	if (!target->using_rdma_cm) {
2406 		ret = -ENOMEM;
2407 		qp_attr = kmalloc_obj(*qp_attr);
2408 		if (!qp_attr)
2409 			goto error;
2410 
2411 		qp_attr->qp_state = IB_QPS_RTR;
2412 		ret = ib_cm_init_qp_attr(cm_id, qp_attr, &attr_mask);
2413 		if (ret)
2414 			goto error_free;
2415 
2416 		ret = ib_modify_qp(ch->qp, qp_attr, attr_mask);
2417 		if (ret)
2418 			goto error_free;
2419 
2420 		qp_attr->qp_state = IB_QPS_RTS;
2421 		ret = ib_cm_init_qp_attr(cm_id, qp_attr, &attr_mask);
2422 		if (ret)
2423 			goto error_free;
2424 
2425 		target->rq_tmo_jiffies = srp_compute_rq_tmo(qp_attr, attr_mask);
2426 
2427 		ret = ib_modify_qp(ch->qp, qp_attr, attr_mask);
2428 		if (ret)
2429 			goto error_free;
2430 
2431 		ret = ib_send_cm_rtu(cm_id, NULL, 0);
2432 	}
2433 
2434 error_free:
2435 	kfree(qp_attr);
2436 
2437 error:
2438 	ch->status = ret;
2439 }
2440 
2441 static void srp_ib_cm_rej_handler(struct ib_cm_id *cm_id,
2442 				  const struct ib_cm_event *event,
2443 				  struct srp_rdma_ch *ch)
2444 {
2445 	struct srp_target_port *target = ch->target;
2446 	struct Scsi_Host *shost = target->scsi_host;
2447 	struct ib_class_port_info *cpi;
2448 	int opcode;
2449 	u16 dlid;
2450 
2451 	switch (event->param.rej_rcvd.reason) {
2452 	case IB_CM_REJ_PORT_CM_REDIRECT:
2453 		cpi = event->param.rej_rcvd.ari;
2454 		dlid = be16_to_cpu(cpi->redirect_lid);
2455 		sa_path_set_dlid(&ch->ib_cm.path, dlid);
2456 		ch->ib_cm.path.pkey = cpi->redirect_pkey;
2457 		cm_id->remote_cm_qpn = be32_to_cpu(cpi->redirect_qp) & 0x00ffffff;
2458 		memcpy(ch->ib_cm.path.dgid.raw, cpi->redirect_gid, 16);
2459 
2460 		ch->status = dlid ? SRP_DLID_REDIRECT : SRP_PORT_REDIRECT;
2461 		break;
2462 
2463 	case IB_CM_REJ_PORT_REDIRECT:
2464 		if (srp_target_is_topspin(target)) {
2465 			union ib_gid *dgid = &ch->ib_cm.path.dgid;
2466 
2467 			/*
2468 			 * Topspin/Cisco SRP gateways incorrectly send
2469 			 * reject reason code 25 when they mean 24
2470 			 * (port redirect).
2471 			 */
2472 			memcpy(dgid->raw, event->param.rej_rcvd.ari, 16);
2473 
2474 			shost_printk(KERN_DEBUG, shost,
2475 				     PFX "Topspin/Cisco redirect to target port GID %016llx%016llx\n",
2476 				     be64_to_cpu(dgid->global.subnet_prefix),
2477 				     be64_to_cpu(dgid->global.interface_id));
2478 
2479 			ch->status = SRP_PORT_REDIRECT;
2480 		} else {
2481 			shost_printk(KERN_WARNING, shost,
2482 				     "  REJ reason: IB_CM_REJ_PORT_REDIRECT\n");
2483 			ch->status = -ECONNRESET;
2484 		}
2485 		break;
2486 
2487 	case IB_CM_REJ_DUPLICATE_LOCAL_COMM_ID:
2488 		shost_printk(KERN_WARNING, shost,
2489 			    "  REJ reason: IB_CM_REJ_DUPLICATE_LOCAL_COMM_ID\n");
2490 		ch->status = -ECONNRESET;
2491 		break;
2492 
2493 	case IB_CM_REJ_CONSUMER_DEFINED:
2494 		opcode = *(u8 *) event->private_data;
2495 		if (opcode == SRP_LOGIN_REJ) {
2496 			struct srp_login_rej *rej = event->private_data;
2497 			u32 reason = be32_to_cpu(rej->reason);
2498 
2499 			if (reason == SRP_LOGIN_REJ_REQ_IT_IU_LENGTH_TOO_LARGE)
2500 				shost_printk(KERN_WARNING, shost,
2501 					     PFX "SRP_LOGIN_REJ: requested max_it_iu_len too large\n");
2502 			else
2503 				shost_printk(KERN_WARNING, shost, PFX
2504 					     "SRP LOGIN from %pI6 to %pI6 REJECTED, reason 0x%08x\n",
2505 					     target->sgid.raw,
2506 					     target->ib_cm.orig_dgid.raw,
2507 					     reason);
2508 		} else
2509 			shost_printk(KERN_WARNING, shost,
2510 				     "  REJ reason: IB_CM_REJ_CONSUMER_DEFINED,"
2511 				     " opcode 0x%02x\n", opcode);
2512 		ch->status = -ECONNRESET;
2513 		break;
2514 
2515 	case IB_CM_REJ_STALE_CONN:
2516 		shost_printk(KERN_WARNING, shost, "  REJ reason: stale connection\n");
2517 		ch->status = SRP_STALE_CONN;
2518 		break;
2519 
2520 	default:
2521 		shost_printk(KERN_WARNING, shost, "  REJ reason 0x%x\n",
2522 			     event->param.rej_rcvd.reason);
2523 		ch->status = -ECONNRESET;
2524 	}
2525 }
2526 
2527 static int srp_ib_cm_handler(struct ib_cm_id *cm_id,
2528 			     const struct ib_cm_event *event)
2529 {
2530 	struct srp_rdma_ch *ch = cm_id->context;
2531 	struct srp_target_port *target = ch->target;
2532 	int comp = 0;
2533 
2534 	switch (event->event) {
2535 	case IB_CM_REQ_ERROR:
2536 		shost_printk(KERN_DEBUG, target->scsi_host,
2537 			     PFX "Sending CM REQ failed\n");
2538 		comp = 1;
2539 		ch->status = -ECONNRESET;
2540 		break;
2541 
2542 	case IB_CM_REP_RECEIVED:
2543 		comp = 1;
2544 		srp_cm_rep_handler(cm_id, event->private_data, ch);
2545 		break;
2546 
2547 	case IB_CM_REJ_RECEIVED:
2548 		shost_printk(KERN_DEBUG, target->scsi_host, PFX "REJ received\n");
2549 		comp = 1;
2550 
2551 		srp_ib_cm_rej_handler(cm_id, event, ch);
2552 		break;
2553 
2554 	case IB_CM_DREQ_RECEIVED:
2555 		shost_printk(KERN_WARNING, target->scsi_host,
2556 			     PFX "DREQ received - connection closed\n");
2557 		ch->connected = false;
2558 		if (ib_send_cm_drep(cm_id, NULL, 0))
2559 			shost_printk(KERN_ERR, target->scsi_host,
2560 				     PFX "Sending CM DREP failed\n");
2561 		queue_work(system_long_wq, &target->tl_err_work);
2562 		break;
2563 
2564 	case IB_CM_TIMEWAIT_EXIT:
2565 		shost_printk(KERN_ERR, target->scsi_host,
2566 			     PFX "connection closed\n");
2567 		comp = 1;
2568 
2569 		ch->status = 0;
2570 		break;
2571 
2572 	case IB_CM_MRA_RECEIVED:
2573 	case IB_CM_DREQ_ERROR:
2574 	case IB_CM_DREP_RECEIVED:
2575 		break;
2576 
2577 	default:
2578 		shost_printk(KERN_WARNING, target->scsi_host,
2579 			     PFX "Unhandled CM event %d\n", event->event);
2580 		break;
2581 	}
2582 
2583 	if (comp)
2584 		complete(&ch->done);
2585 
2586 	return 0;
2587 }
2588 
2589 static void srp_rdma_cm_rej_handler(struct srp_rdma_ch *ch,
2590 				    struct rdma_cm_event *event)
2591 {
2592 	struct srp_target_port *target = ch->target;
2593 	struct Scsi_Host *shost = target->scsi_host;
2594 	int opcode;
2595 
2596 	switch (event->status) {
2597 	case IB_CM_REJ_DUPLICATE_LOCAL_COMM_ID:
2598 		shost_printk(KERN_WARNING, shost,
2599 			    "  REJ reason: IB_CM_REJ_DUPLICATE_LOCAL_COMM_ID\n");
2600 		ch->status = -ECONNRESET;
2601 		break;
2602 
2603 	case IB_CM_REJ_CONSUMER_DEFINED:
2604 		opcode = *(u8 *) event->param.conn.private_data;
2605 		if (opcode == SRP_LOGIN_REJ) {
2606 			struct srp_login_rej *rej =
2607 				(struct srp_login_rej *)
2608 				event->param.conn.private_data;
2609 			u32 reason = be32_to_cpu(rej->reason);
2610 
2611 			if (reason == SRP_LOGIN_REJ_REQ_IT_IU_LENGTH_TOO_LARGE)
2612 				shost_printk(KERN_WARNING, shost,
2613 					     PFX "SRP_LOGIN_REJ: requested max_it_iu_len too large\n");
2614 			else
2615 				shost_printk(KERN_WARNING, shost,
2616 					    PFX "SRP LOGIN REJECTED, reason 0x%08x\n", reason);
2617 		} else {
2618 			shost_printk(KERN_WARNING, shost,
2619 				     "  REJ reason: IB_CM_REJ_CONSUMER_DEFINED, opcode 0x%02x\n",
2620 				     opcode);
2621 		}
2622 		ch->status = -ECONNRESET;
2623 		break;
2624 
2625 	case IB_CM_REJ_STALE_CONN:
2626 		shost_printk(KERN_WARNING, shost,
2627 			     "  REJ reason: stale connection\n");
2628 		ch->status = SRP_STALE_CONN;
2629 		break;
2630 
2631 	default:
2632 		shost_printk(KERN_WARNING, shost, "  REJ reason 0x%x\n",
2633 			     event->status);
2634 		ch->status = -ECONNRESET;
2635 		break;
2636 	}
2637 }
2638 
2639 static int srp_rdma_cm_handler(struct rdma_cm_id *cm_id,
2640 			       struct rdma_cm_event *event)
2641 {
2642 	struct srp_rdma_ch *ch = cm_id->context;
2643 	struct srp_target_port *target = ch->target;
2644 	int comp = 0;
2645 
2646 	switch (event->event) {
2647 	case RDMA_CM_EVENT_ADDR_RESOLVED:
2648 		ch->status = 0;
2649 		comp = 1;
2650 		break;
2651 
2652 	case RDMA_CM_EVENT_ADDR_ERROR:
2653 		ch->status = -ENXIO;
2654 		comp = 1;
2655 		break;
2656 
2657 	case RDMA_CM_EVENT_ROUTE_RESOLVED:
2658 		ch->status = 0;
2659 		comp = 1;
2660 		break;
2661 
2662 	case RDMA_CM_EVENT_ROUTE_ERROR:
2663 	case RDMA_CM_EVENT_UNREACHABLE:
2664 		ch->status = -EHOSTUNREACH;
2665 		comp = 1;
2666 		break;
2667 
2668 	case RDMA_CM_EVENT_CONNECT_ERROR:
2669 		shost_printk(KERN_DEBUG, target->scsi_host,
2670 			     PFX "Sending CM REQ failed\n");
2671 		comp = 1;
2672 		ch->status = -ECONNRESET;
2673 		break;
2674 
2675 	case RDMA_CM_EVENT_ESTABLISHED:
2676 		comp = 1;
2677 		srp_cm_rep_handler(NULL, event->param.conn.private_data, ch);
2678 		break;
2679 
2680 	case RDMA_CM_EVENT_REJECTED:
2681 		shost_printk(KERN_DEBUG, target->scsi_host, PFX "REJ received\n");
2682 		comp = 1;
2683 
2684 		srp_rdma_cm_rej_handler(ch, event);
2685 		break;
2686 
2687 	case RDMA_CM_EVENT_DISCONNECTED:
2688 		if (ch->connected) {
2689 			shost_printk(KERN_WARNING, target->scsi_host,
2690 				     PFX "received DREQ\n");
2691 			rdma_disconnect(ch->rdma_cm.cm_id);
2692 			comp = 1;
2693 			ch->status = 0;
2694 			queue_work(system_long_wq, &target->tl_err_work);
2695 		}
2696 		break;
2697 
2698 	case RDMA_CM_EVENT_TIMEWAIT_EXIT:
2699 		shost_printk(KERN_ERR, target->scsi_host,
2700 			     PFX "connection closed\n");
2701 
2702 		comp = 1;
2703 		ch->status = 0;
2704 		break;
2705 
2706 	default:
2707 		shost_printk(KERN_WARNING, target->scsi_host,
2708 			     PFX "Unhandled CM event %d\n", event->event);
2709 		break;
2710 	}
2711 
2712 	if (comp)
2713 		complete(&ch->done);
2714 
2715 	return 0;
2716 }
2717 
2718 /**
2719  * srp_change_queue_depth - setting device queue depth
2720  * @sdev: scsi device struct
2721  * @qdepth: requested queue depth
2722  *
2723  * Returns queue depth.
2724  */
2725 static int
2726 srp_change_queue_depth(struct scsi_device *sdev, int qdepth)
2727 {
2728 	if (!sdev->tagged_supported)
2729 		qdepth = 1;
2730 	return scsi_change_queue_depth(sdev, qdepth);
2731 }
2732 
2733 static int srp_send_tsk_mgmt(struct srp_rdma_ch *ch, u64 req_tag, u64 lun,
2734 			     u8 func, u8 *status)
2735 {
2736 	struct srp_target_port *target = ch->target;
2737 	struct srp_rport *rport = target->rport;
2738 	struct ib_device *dev = target->srp_host->srp_dev->dev;
2739 	struct srp_iu *iu;
2740 	struct srp_tsk_mgmt *tsk_mgmt;
2741 	int res;
2742 
2743 	if (!ch->connected || target->qp_in_error)
2744 		return -1;
2745 
2746 	/*
2747 	 * Lock the rport mutex to avoid that srp_create_ch_ib() is
2748 	 * invoked while a task management function is being sent.
2749 	 */
2750 	mutex_lock(&rport->mutex);
2751 	spin_lock_irq(&ch->lock);
2752 	iu = __srp_get_tx_iu(ch, SRP_IU_TSK_MGMT);
2753 	spin_unlock_irq(&ch->lock);
2754 
2755 	if (!iu) {
2756 		mutex_unlock(&rport->mutex);
2757 
2758 		return -1;
2759 	}
2760 
2761 	iu->num_sge = 1;
2762 
2763 	ib_dma_sync_single_for_cpu(dev, iu->dma, sizeof *tsk_mgmt,
2764 				   DMA_TO_DEVICE);
2765 	tsk_mgmt = iu->buf;
2766 	memset(tsk_mgmt, 0, sizeof *tsk_mgmt);
2767 
2768 	tsk_mgmt->opcode 	= SRP_TSK_MGMT;
2769 	int_to_scsilun(lun, &tsk_mgmt->lun);
2770 	tsk_mgmt->tsk_mgmt_func = func;
2771 	tsk_mgmt->task_tag	= req_tag;
2772 
2773 	spin_lock_irq(&ch->lock);
2774 	ch->tsk_mgmt_tag = (ch->tsk_mgmt_tag + 1) | SRP_TAG_TSK_MGMT;
2775 	tsk_mgmt->tag = ch->tsk_mgmt_tag;
2776 	spin_unlock_irq(&ch->lock);
2777 
2778 	init_completion(&ch->tsk_mgmt_done);
2779 
2780 	ib_dma_sync_single_for_device(dev, iu->dma, sizeof *tsk_mgmt,
2781 				      DMA_TO_DEVICE);
2782 	if (srp_post_send(ch, iu, sizeof(*tsk_mgmt))) {
2783 		srp_put_tx_iu(ch, iu, SRP_IU_TSK_MGMT);
2784 		mutex_unlock(&rport->mutex);
2785 
2786 		return -1;
2787 	}
2788 	res = wait_for_completion_timeout(&ch->tsk_mgmt_done,
2789 					msecs_to_jiffies(SRP_ABORT_TIMEOUT_MS));
2790 	if (res > 0 && status)
2791 		*status = ch->tsk_mgmt_status;
2792 	mutex_unlock(&rport->mutex);
2793 
2794 	WARN_ON_ONCE(res < 0);
2795 
2796 	return res > 0 ? 0 : -1;
2797 }
2798 
2799 static int srp_abort(struct scsi_cmnd *scmnd)
2800 {
2801 	struct srp_target_port *target = host_to_target(scmnd->device->host);
2802 	struct srp_request *req = scsi_cmd_priv(scmnd);
2803 	u32 tag;
2804 	u16 ch_idx;
2805 	struct srp_rdma_ch *ch;
2806 
2807 	shost_printk(KERN_ERR, target->scsi_host, "SRP abort called\n");
2808 
2809 	tag = blk_mq_unique_tag(scsi_cmd_to_rq(scmnd));
2810 	ch_idx = blk_mq_unique_tag_to_hwq(tag);
2811 	if (WARN_ON_ONCE(ch_idx >= target->ch_count))
2812 		return SUCCESS;
2813 	ch = &target->ch[ch_idx];
2814 	if (!srp_claim_req(ch, req, NULL, scmnd))
2815 		return SUCCESS;
2816 	shost_printk(KERN_ERR, target->scsi_host,
2817 		     "Sending SRP abort for tag %#x\n", tag);
2818 	if (srp_send_tsk_mgmt(ch, tag, scmnd->device->lun,
2819 			      SRP_TSK_ABORT_TASK, NULL) == 0) {
2820 		srp_free_req(ch, req, scmnd, 0);
2821 		return SUCCESS;
2822 	}
2823 	if (target->rport->state == SRP_RPORT_LOST)
2824 		return FAST_IO_FAIL;
2825 
2826 	return FAILED;
2827 }
2828 
2829 static int srp_reset_device(struct scsi_cmnd *scmnd)
2830 {
2831 	struct srp_target_port *target = host_to_target(scmnd->device->host);
2832 	struct srp_rdma_ch *ch;
2833 	u8 status;
2834 
2835 	shost_printk(KERN_ERR, target->scsi_host, "SRP reset_device called\n");
2836 
2837 	ch = &target->ch[0];
2838 	if (srp_send_tsk_mgmt(ch, SRP_TAG_NO_REQ, scmnd->device->lun,
2839 			      SRP_TSK_LUN_RESET, &status))
2840 		return FAILED;
2841 	if (status)
2842 		return FAILED;
2843 
2844 	return SUCCESS;
2845 }
2846 
2847 static int srp_reset_host(struct scsi_cmnd *scmnd)
2848 {
2849 	struct srp_target_port *target = host_to_target(scmnd->device->host);
2850 
2851 	shost_printk(KERN_ERR, target->scsi_host, PFX "SRP reset_host called\n");
2852 
2853 	return srp_reconnect_rport(target->rport) == 0 ? SUCCESS : FAILED;
2854 }
2855 
2856 static int srp_target_alloc(struct scsi_target *starget)
2857 {
2858 	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
2859 	struct srp_target_port *target = host_to_target(shost);
2860 
2861 	if (target->target_can_queue)
2862 		starget->can_queue = target->target_can_queue;
2863 	return 0;
2864 }
2865 
2866 static int srp_sdev_configure(struct scsi_device *sdev,
2867 			      struct queue_limits *lim)
2868 {
2869 	struct Scsi_Host *shost = sdev->host;
2870 	struct srp_target_port *target = host_to_target(shost);
2871 	struct request_queue *q = sdev->request_queue;
2872 	unsigned long timeout;
2873 
2874 	if (sdev->type == TYPE_DISK) {
2875 		timeout = max_t(unsigned, 30 * HZ, target->rq_tmo_jiffies);
2876 		blk_queue_rq_timeout(q, timeout);
2877 	}
2878 
2879 	return 0;
2880 }
2881 
2882 static ssize_t id_ext_show(struct device *dev, struct device_attribute *attr,
2883 			   char *buf)
2884 {
2885 	struct srp_target_port *target = host_to_target(class_to_shost(dev));
2886 
2887 	return sysfs_emit(buf, "0x%016llx\n", be64_to_cpu(target->id_ext));
2888 }
2889 
2890 static DEVICE_ATTR_RO(id_ext);
2891 
2892 static ssize_t ioc_guid_show(struct device *dev, struct device_attribute *attr,
2893 			     char *buf)
2894 {
2895 	struct srp_target_port *target = host_to_target(class_to_shost(dev));
2896 
2897 	return sysfs_emit(buf, "0x%016llx\n", be64_to_cpu(target->ioc_guid));
2898 }
2899 
2900 static DEVICE_ATTR_RO(ioc_guid);
2901 
2902 static ssize_t service_id_show(struct device *dev,
2903 			       struct device_attribute *attr, char *buf)
2904 {
2905 	struct srp_target_port *target = host_to_target(class_to_shost(dev));
2906 
2907 	if (target->using_rdma_cm)
2908 		return -ENOENT;
2909 	return sysfs_emit(buf, "0x%016llx\n",
2910 			  be64_to_cpu(target->ib_cm.service_id));
2911 }
2912 
2913 static DEVICE_ATTR_RO(service_id);
2914 
2915 static ssize_t pkey_show(struct device *dev, struct device_attribute *attr,
2916 			 char *buf)
2917 {
2918 	struct srp_target_port *target = host_to_target(class_to_shost(dev));
2919 
2920 	if (target->using_rdma_cm)
2921 		return -ENOENT;
2922 
2923 	return sysfs_emit(buf, "0x%04x\n", be16_to_cpu(target->ib_cm.pkey));
2924 }
2925 
2926 static DEVICE_ATTR_RO(pkey);
2927 
2928 static ssize_t sgid_show(struct device *dev, struct device_attribute *attr,
2929 			 char *buf)
2930 {
2931 	struct srp_target_port *target = host_to_target(class_to_shost(dev));
2932 
2933 	return sysfs_emit(buf, "%pI6\n", target->sgid.raw);
2934 }
2935 
2936 static DEVICE_ATTR_RO(sgid);
2937 
2938 static ssize_t dgid_show(struct device *dev, struct device_attribute *attr,
2939 			 char *buf)
2940 {
2941 	struct srp_target_port *target = host_to_target(class_to_shost(dev));
2942 	struct srp_rdma_ch *ch = &target->ch[0];
2943 
2944 	if (target->using_rdma_cm)
2945 		return -ENOENT;
2946 
2947 	return sysfs_emit(buf, "%pI6\n", ch->ib_cm.path.dgid.raw);
2948 }
2949 
2950 static DEVICE_ATTR_RO(dgid);
2951 
2952 static ssize_t orig_dgid_show(struct device *dev, struct device_attribute *attr,
2953 			      char *buf)
2954 {
2955 	struct srp_target_port *target = host_to_target(class_to_shost(dev));
2956 
2957 	if (target->using_rdma_cm)
2958 		return -ENOENT;
2959 
2960 	return sysfs_emit(buf, "%pI6\n", target->ib_cm.orig_dgid.raw);
2961 }
2962 
2963 static DEVICE_ATTR_RO(orig_dgid);
2964 
2965 static ssize_t req_lim_show(struct device *dev, struct device_attribute *attr,
2966 			    char *buf)
2967 {
2968 	struct srp_target_port *target = host_to_target(class_to_shost(dev));
2969 	struct srp_rdma_ch *ch;
2970 	int i, req_lim = INT_MAX;
2971 
2972 	for (i = 0; i < target->ch_count; i++) {
2973 		ch = &target->ch[i];
2974 		req_lim = min(req_lim, ch->req_lim);
2975 	}
2976 
2977 	return sysfs_emit(buf, "%d\n", req_lim);
2978 }
2979 
2980 static DEVICE_ATTR_RO(req_lim);
2981 
2982 static ssize_t zero_req_lim_show(struct device *dev,
2983 				 struct device_attribute *attr, char *buf)
2984 {
2985 	struct srp_target_port *target = host_to_target(class_to_shost(dev));
2986 
2987 	return sysfs_emit(buf, "%d\n", target->zero_req_lim);
2988 }
2989 
2990 static DEVICE_ATTR_RO(zero_req_lim);
2991 
2992 static ssize_t local_ib_port_show(struct device *dev,
2993 				  struct device_attribute *attr, char *buf)
2994 {
2995 	struct srp_target_port *target = host_to_target(class_to_shost(dev));
2996 
2997 	return sysfs_emit(buf, "%u\n", target->srp_host->port);
2998 }
2999 
3000 static DEVICE_ATTR_RO(local_ib_port);
3001 
3002 static ssize_t local_ib_device_show(struct device *dev,
3003 				    struct device_attribute *attr, char *buf)
3004 {
3005 	struct srp_target_port *target = host_to_target(class_to_shost(dev));
3006 
3007 	return sysfs_emit(buf, "%s\n",
3008 			  dev_name(&target->srp_host->srp_dev->dev->dev));
3009 }
3010 
3011 static DEVICE_ATTR_RO(local_ib_device);
3012 
3013 static ssize_t ch_count_show(struct device *dev, struct device_attribute *attr,
3014 			     char *buf)
3015 {
3016 	struct srp_target_port *target = host_to_target(class_to_shost(dev));
3017 
3018 	return sysfs_emit(buf, "%d\n", target->ch_count);
3019 }
3020 
3021 static DEVICE_ATTR_RO(ch_count);
3022 
3023 static ssize_t comp_vector_show(struct device *dev,
3024 				struct device_attribute *attr, char *buf)
3025 {
3026 	struct srp_target_port *target = host_to_target(class_to_shost(dev));
3027 
3028 	return sysfs_emit(buf, "%d\n", target->comp_vector);
3029 }
3030 
3031 static DEVICE_ATTR_RO(comp_vector);
3032 
3033 static ssize_t tl_retry_count_show(struct device *dev,
3034 				   struct device_attribute *attr, char *buf)
3035 {
3036 	struct srp_target_port *target = host_to_target(class_to_shost(dev));
3037 
3038 	return sysfs_emit(buf, "%d\n", target->tl_retry_count);
3039 }
3040 
3041 static DEVICE_ATTR_RO(tl_retry_count);
3042 
3043 static ssize_t cmd_sg_entries_show(struct device *dev,
3044 				   struct device_attribute *attr, char *buf)
3045 {
3046 	struct srp_target_port *target = host_to_target(class_to_shost(dev));
3047 
3048 	return sysfs_emit(buf, "%u\n", target->cmd_sg_cnt);
3049 }
3050 
3051 static DEVICE_ATTR_RO(cmd_sg_entries);
3052 
3053 static ssize_t allow_ext_sg_show(struct device *dev,
3054 				 struct device_attribute *attr, char *buf)
3055 {
3056 	struct srp_target_port *target = host_to_target(class_to_shost(dev));
3057 
3058 	return sysfs_emit(buf, "%s\n", target->allow_ext_sg ? "true" : "false");
3059 }
3060 
3061 static DEVICE_ATTR_RO(allow_ext_sg);
3062 
3063 static struct attribute *srp_host_attrs[] = {
3064 	&dev_attr_id_ext.attr,
3065 	&dev_attr_ioc_guid.attr,
3066 	&dev_attr_service_id.attr,
3067 	&dev_attr_pkey.attr,
3068 	&dev_attr_sgid.attr,
3069 	&dev_attr_dgid.attr,
3070 	&dev_attr_orig_dgid.attr,
3071 	&dev_attr_req_lim.attr,
3072 	&dev_attr_zero_req_lim.attr,
3073 	&dev_attr_local_ib_port.attr,
3074 	&dev_attr_local_ib_device.attr,
3075 	&dev_attr_ch_count.attr,
3076 	&dev_attr_comp_vector.attr,
3077 	&dev_attr_tl_retry_count.attr,
3078 	&dev_attr_cmd_sg_entries.attr,
3079 	&dev_attr_allow_ext_sg.attr,
3080 	NULL
3081 };
3082 
3083 ATTRIBUTE_GROUPS(srp_host);
3084 
3085 static const struct scsi_host_template srp_template = {
3086 	.module				= THIS_MODULE,
3087 	.name				= "InfiniBand SRP initiator",
3088 	.proc_name			= DRV_NAME,
3089 	.target_alloc			= srp_target_alloc,
3090 	.sdev_configure			= srp_sdev_configure,
3091 	.info				= srp_target_info,
3092 	.init_cmd_priv			= srp_init_cmd_priv,
3093 	.exit_cmd_priv			= srp_exit_cmd_priv,
3094 	.queuecommand			= srp_queuecommand,
3095 	.change_queue_depth             = srp_change_queue_depth,
3096 	.eh_timed_out			= srp_timed_out,
3097 	.eh_abort_handler		= srp_abort,
3098 	.eh_device_reset_handler	= srp_reset_device,
3099 	.eh_host_reset_handler		= srp_reset_host,
3100 	.skip_settle_delay		= true,
3101 	.sg_tablesize			= SRP_DEF_SG_TABLESIZE,
3102 	.can_queue			= SRP_DEFAULT_CMD_SQ_SIZE,
3103 	.this_id			= -1,
3104 	.cmd_per_lun			= SRP_DEFAULT_CMD_SQ_SIZE,
3105 	.shost_groups			= srp_host_groups,
3106 	.track_queue_depth		= 1,
3107 	.cmd_size			= sizeof(struct srp_request),
3108 };
3109 
3110 static int srp_sdev_count(struct Scsi_Host *host)
3111 {
3112 	struct scsi_device *sdev;
3113 	int c = 0;
3114 
3115 	shost_for_each_device(sdev, host)
3116 		c++;
3117 
3118 	return c;
3119 }
3120 
3121 /*
3122  * Return values:
3123  * < 0 upon failure. Caller is responsible for SRP target port cleanup.
3124  * 0 and target->state == SRP_TARGET_REMOVED if asynchronous target port
3125  *    removal has been scheduled.
3126  * 0 and target->state != SRP_TARGET_REMOVED upon success.
3127  */
3128 static int srp_add_target(struct srp_host *host, struct srp_target_port *target)
3129 {
3130 	struct srp_rport_identifiers ids;
3131 	struct srp_rport *rport;
3132 
3133 	target->state = SRP_TARGET_SCANNING;
3134 	sprintf(target->target_name, "SRP.T10:%016llX",
3135 		be64_to_cpu(target->id_ext));
3136 
3137 	if (scsi_add_host(target->scsi_host, host->srp_dev->dev->dev.parent))
3138 		return -ENODEV;
3139 
3140 	memcpy(ids.port_id, &target->id_ext, 8);
3141 	memcpy(ids.port_id + 8, &target->ioc_guid, 8);
3142 	ids.roles = SRP_RPORT_ROLE_TARGET;
3143 	rport = srp_rport_add(target->scsi_host, &ids);
3144 	if (IS_ERR(rport)) {
3145 		scsi_remove_host(target->scsi_host);
3146 		return PTR_ERR(rport);
3147 	}
3148 
3149 	rport->lld_data = target;
3150 	target->rport = rport;
3151 
3152 	spin_lock(&host->target_lock);
3153 	list_add_tail(&target->list, &host->target_list);
3154 	spin_unlock(&host->target_lock);
3155 
3156 	scsi_scan_target(&target->scsi_host->shost_gendev,
3157 			 0, target->scsi_id, SCAN_WILD_CARD, SCSI_SCAN_INITIAL);
3158 
3159 	if (srp_connected_ch(target) < target->ch_count ||
3160 	    target->qp_in_error) {
3161 		shost_printk(KERN_INFO, target->scsi_host,
3162 			     PFX "SCSI scan failed - removing SCSI host\n");
3163 		srp_queue_remove_work(target);
3164 		goto out;
3165 	}
3166 
3167 	pr_debug("%s: SCSI scan succeeded - detected %d LUNs\n",
3168 		 dev_name(&target->scsi_host->shost_gendev),
3169 		 srp_sdev_count(target->scsi_host));
3170 
3171 	spin_lock_irq(&target->lock);
3172 	if (target->state == SRP_TARGET_SCANNING)
3173 		target->state = SRP_TARGET_LIVE;
3174 	spin_unlock_irq(&target->lock);
3175 
3176 out:
3177 	return 0;
3178 }
3179 
3180 static void srp_release_dev(struct device *dev)
3181 {
3182 	struct srp_host *host =
3183 		container_of(dev, struct srp_host, dev);
3184 
3185 	kfree(host);
3186 }
3187 
3188 static struct attribute *srp_class_attrs[];
3189 
3190 ATTRIBUTE_GROUPS(srp_class);
3191 
3192 static struct class srp_class = {
3193 	.name    = "infiniband_srp",
3194 	.dev_groups = srp_class_groups,
3195 	.dev_release = srp_release_dev
3196 };
3197 
3198 /**
3199  * srp_conn_unique() - check whether the connection to a target is unique
3200  * @host:   SRP host.
3201  * @target: SRP target port.
3202  */
3203 static bool srp_conn_unique(struct srp_host *host,
3204 			    struct srp_target_port *target)
3205 {
3206 	struct srp_target_port *t;
3207 	bool ret = false;
3208 
3209 	if (target->state == SRP_TARGET_REMOVED)
3210 		goto out;
3211 
3212 	ret = true;
3213 
3214 	spin_lock(&host->target_lock);
3215 	list_for_each_entry(t, &host->target_list, list) {
3216 		if (t != target &&
3217 		    target->id_ext == t->id_ext &&
3218 		    target->ioc_guid == t->ioc_guid &&
3219 		    target->initiator_ext == t->initiator_ext) {
3220 			ret = false;
3221 			break;
3222 		}
3223 	}
3224 	spin_unlock(&host->target_lock);
3225 
3226 out:
3227 	return ret;
3228 }
3229 
3230 /*
3231  * Target ports are added by writing
3232  *
3233  *     id_ext=<SRP ID ext>,ioc_guid=<SRP IOC GUID>,dgid=<dest GID>,
3234  *     pkey=<P_Key>,service_id=<service ID>
3235  * or
3236  *     id_ext=<SRP ID ext>,ioc_guid=<SRP IOC GUID>,
3237  *     [src=<IPv4 address>,]dest=<IPv4 address>:<port number>
3238  *
3239  * to the add_target sysfs attribute.
3240  */
3241 enum {
3242 	SRP_OPT_ERR		= 0,
3243 	SRP_OPT_ID_EXT		= 1 << 0,
3244 	SRP_OPT_IOC_GUID	= 1 << 1,
3245 	SRP_OPT_DGID		= 1 << 2,
3246 	SRP_OPT_PKEY		= 1 << 3,
3247 	SRP_OPT_SERVICE_ID	= 1 << 4,
3248 	SRP_OPT_MAX_SECT	= 1 << 5,
3249 	SRP_OPT_MAX_CMD_PER_LUN	= 1 << 6,
3250 	SRP_OPT_IO_CLASS	= 1 << 7,
3251 	SRP_OPT_INITIATOR_EXT	= 1 << 8,
3252 	SRP_OPT_CMD_SG_ENTRIES	= 1 << 9,
3253 	SRP_OPT_ALLOW_EXT_SG	= 1 << 10,
3254 	SRP_OPT_SG_TABLESIZE	= 1 << 11,
3255 	SRP_OPT_COMP_VECTOR	= 1 << 12,
3256 	SRP_OPT_TL_RETRY_COUNT	= 1 << 13,
3257 	SRP_OPT_QUEUE_SIZE	= 1 << 14,
3258 	SRP_OPT_IP_SRC		= 1 << 15,
3259 	SRP_OPT_IP_DEST		= 1 << 16,
3260 	SRP_OPT_TARGET_CAN_QUEUE= 1 << 17,
3261 	SRP_OPT_MAX_IT_IU_SIZE  = 1 << 18,
3262 	SRP_OPT_CH_COUNT	= 1 << 19,
3263 };
3264 
3265 static unsigned int srp_opt_mandatory[] = {
3266 	SRP_OPT_ID_EXT		|
3267 	SRP_OPT_IOC_GUID	|
3268 	SRP_OPT_DGID		|
3269 	SRP_OPT_PKEY		|
3270 	SRP_OPT_SERVICE_ID,
3271 	SRP_OPT_ID_EXT		|
3272 	SRP_OPT_IOC_GUID	|
3273 	SRP_OPT_IP_DEST,
3274 };
3275 
3276 static const match_table_t srp_opt_tokens = {
3277 	{ SRP_OPT_ID_EXT,		"id_ext=%s" 		},
3278 	{ SRP_OPT_IOC_GUID,		"ioc_guid=%s" 		},
3279 	{ SRP_OPT_DGID,			"dgid=%s" 		},
3280 	{ SRP_OPT_PKEY,			"pkey=%x" 		},
3281 	{ SRP_OPT_SERVICE_ID,		"service_id=%s"		},
3282 	{ SRP_OPT_MAX_SECT,		"max_sect=%d" 		},
3283 	{ SRP_OPT_MAX_CMD_PER_LUN,	"max_cmd_per_lun=%d" 	},
3284 	{ SRP_OPT_TARGET_CAN_QUEUE,	"target_can_queue=%d"	},
3285 	{ SRP_OPT_IO_CLASS,		"io_class=%x"		},
3286 	{ SRP_OPT_INITIATOR_EXT,	"initiator_ext=%s"	},
3287 	{ SRP_OPT_CMD_SG_ENTRIES,	"cmd_sg_entries=%u"	},
3288 	{ SRP_OPT_ALLOW_EXT_SG,		"allow_ext_sg=%u"	},
3289 	{ SRP_OPT_SG_TABLESIZE,		"sg_tablesize=%u"	},
3290 	{ SRP_OPT_COMP_VECTOR,		"comp_vector=%u"	},
3291 	{ SRP_OPT_TL_RETRY_COUNT,	"tl_retry_count=%u"	},
3292 	{ SRP_OPT_QUEUE_SIZE,		"queue_size=%d"		},
3293 	{ SRP_OPT_IP_SRC,		"src=%s"		},
3294 	{ SRP_OPT_IP_DEST,		"dest=%s"		},
3295 	{ SRP_OPT_MAX_IT_IU_SIZE,	"max_it_iu_size=%d"	},
3296 	{ SRP_OPT_CH_COUNT,		"ch_count=%u",		},
3297 	{ SRP_OPT_ERR,			NULL 			}
3298 };
3299 
3300 /**
3301  * srp_parse_in - parse an IP address and port number combination
3302  * @net:	   [in]  Network namespace.
3303  * @sa:		   [out] Address family, IP address and port number.
3304  * @addr_port_str: [in]  IP address and port number.
3305  * @has_port:	   [out] Whether or not @addr_port_str includes a port number.
3306  *
3307  * Parse the following address formats:
3308  * - IPv4: <ip_address>:<port>, e.g. 1.2.3.4:5.
3309  * - IPv6: \[<ipv6_address>\]:<port>, e.g. [1::2:3%4]:5.
3310  */
3311 static int srp_parse_in(struct net *net, struct sockaddr_storage *sa,
3312 			const char *addr_port_str, bool *has_port)
3313 {
3314 	char *addr_end, *addr = kstrdup(addr_port_str, GFP_KERNEL);
3315 	char *port_str;
3316 	int ret;
3317 
3318 	if (!addr)
3319 		return -ENOMEM;
3320 	port_str = strrchr(addr, ':');
3321 	if (port_str && strchr(port_str, ']'))
3322 		port_str = NULL;
3323 	if (port_str)
3324 		*port_str++ = '\0';
3325 	if (has_port)
3326 		*has_port = port_str != NULL;
3327 	ret = inet_pton_with_scope(net, AF_INET, addr, port_str, sa);
3328 	if (ret && addr[0]) {
3329 		addr_end = addr + strlen(addr) - 1;
3330 		if (addr[0] == '[' && *addr_end == ']') {
3331 			*addr_end = '\0';
3332 			ret = inet_pton_with_scope(net, AF_INET6, addr + 1,
3333 						   port_str, sa);
3334 		}
3335 	}
3336 	kfree(addr);
3337 	pr_debug("%s -> %pISpfsc\n", addr_port_str, sa);
3338 	return ret;
3339 }
3340 
3341 static int srp_parse_options(struct net *net, const char *buf,
3342 			     struct srp_target_port *target)
3343 {
3344 	char *options, *sep_opt;
3345 	char *p;
3346 	substring_t args[MAX_OPT_ARGS];
3347 	unsigned long long ull;
3348 	bool has_port;
3349 	int opt_mask = 0;
3350 	int token;
3351 	int ret = -EINVAL;
3352 	int i;
3353 
3354 	options = kstrdup(buf, GFP_KERNEL);
3355 	if (!options)
3356 		return -ENOMEM;
3357 
3358 	sep_opt = options;
3359 	while ((p = strsep(&sep_opt, ",\n")) != NULL) {
3360 		if (!*p)
3361 			continue;
3362 
3363 		token = match_token(p, srp_opt_tokens, args);
3364 		opt_mask |= token;
3365 
3366 		switch (token) {
3367 		case SRP_OPT_ID_EXT:
3368 			p = match_strdup(args);
3369 			if (!p) {
3370 				ret = -ENOMEM;
3371 				goto out;
3372 			}
3373 			ret = kstrtoull(p, 16, &ull);
3374 			if (ret) {
3375 				pr_warn("invalid id_ext parameter '%s'\n", p);
3376 				kfree(p);
3377 				goto out;
3378 			}
3379 			target->id_ext = cpu_to_be64(ull);
3380 			kfree(p);
3381 			break;
3382 
3383 		case SRP_OPT_IOC_GUID:
3384 			p = match_strdup(args);
3385 			if (!p) {
3386 				ret = -ENOMEM;
3387 				goto out;
3388 			}
3389 			ret = kstrtoull(p, 16, &ull);
3390 			if (ret) {
3391 				pr_warn("invalid ioc_guid parameter '%s'\n", p);
3392 				kfree(p);
3393 				goto out;
3394 			}
3395 			target->ioc_guid = cpu_to_be64(ull);
3396 			kfree(p);
3397 			break;
3398 
3399 		case SRP_OPT_DGID:
3400 			p = match_strdup(args);
3401 			if (!p) {
3402 				ret = -ENOMEM;
3403 				goto out;
3404 			}
3405 			if (strlen(p) != 32) {
3406 				pr_warn("bad dest GID parameter '%s'\n", p);
3407 				kfree(p);
3408 				goto out;
3409 			}
3410 
3411 			ret = hex2bin(target->ib_cm.orig_dgid.raw, p, 16);
3412 			kfree(p);
3413 			if (ret < 0)
3414 				goto out;
3415 			break;
3416 
3417 		case SRP_OPT_PKEY:
3418 			ret = match_hex(args, &token);
3419 			if (ret) {
3420 				pr_warn("bad P_Key parameter '%s'\n", p);
3421 				goto out;
3422 			}
3423 			target->ib_cm.pkey = cpu_to_be16(token);
3424 			break;
3425 
3426 		case SRP_OPT_SERVICE_ID:
3427 			p = match_strdup(args);
3428 			if (!p) {
3429 				ret = -ENOMEM;
3430 				goto out;
3431 			}
3432 			ret = kstrtoull(p, 16, &ull);
3433 			if (ret) {
3434 				pr_warn("bad service_id parameter '%s'\n", p);
3435 				kfree(p);
3436 				goto out;
3437 			}
3438 			target->ib_cm.service_id = cpu_to_be64(ull);
3439 			kfree(p);
3440 			break;
3441 
3442 		case SRP_OPT_IP_SRC:
3443 			p = match_strdup(args);
3444 			if (!p) {
3445 				ret = -ENOMEM;
3446 				goto out;
3447 			}
3448 			ret = srp_parse_in(net, &target->rdma_cm.src.ss, p,
3449 					   NULL);
3450 			if (ret < 0) {
3451 				pr_warn("bad source parameter '%s'\n", p);
3452 				kfree(p);
3453 				goto out;
3454 			}
3455 			target->rdma_cm.src_specified = true;
3456 			kfree(p);
3457 			break;
3458 
3459 		case SRP_OPT_IP_DEST:
3460 			p = match_strdup(args);
3461 			if (!p) {
3462 				ret = -ENOMEM;
3463 				goto out;
3464 			}
3465 			ret = srp_parse_in(net, &target->rdma_cm.dst.ss, p,
3466 					   &has_port);
3467 			if (!has_port)
3468 				ret = -EINVAL;
3469 			if (ret < 0) {
3470 				pr_warn("bad dest parameter '%s'\n", p);
3471 				kfree(p);
3472 				goto out;
3473 			}
3474 			target->using_rdma_cm = true;
3475 			kfree(p);
3476 			break;
3477 
3478 		case SRP_OPT_MAX_SECT:
3479 			ret = match_int(args, &token);
3480 			if (ret) {
3481 				pr_warn("bad max sect parameter '%s'\n", p);
3482 				goto out;
3483 			}
3484 			target->scsi_host->max_sectors = token;
3485 			break;
3486 
3487 		case SRP_OPT_QUEUE_SIZE:
3488 			ret = match_int(args, &token);
3489 			if (ret) {
3490 				pr_warn("match_int() failed for queue_size parameter '%s', Error %d\n",
3491 					p, ret);
3492 				goto out;
3493 			}
3494 			if (token < 1) {
3495 				pr_warn("bad queue_size parameter '%s'\n", p);
3496 				ret = -EINVAL;
3497 				goto out;
3498 			}
3499 			target->scsi_host->can_queue = token;
3500 			target->queue_size = token + SRP_RSP_SQ_SIZE +
3501 					     SRP_TSK_MGMT_SQ_SIZE;
3502 			if (!(opt_mask & SRP_OPT_MAX_CMD_PER_LUN))
3503 				target->scsi_host->cmd_per_lun = token;
3504 			break;
3505 
3506 		case SRP_OPT_MAX_CMD_PER_LUN:
3507 			ret = match_int(args, &token);
3508 			if (ret) {
3509 				pr_warn("match_int() failed for max cmd_per_lun parameter '%s', Error %d\n",
3510 					p, ret);
3511 				goto out;
3512 			}
3513 			if (token < 1) {
3514 				pr_warn("bad max cmd_per_lun parameter '%s'\n",
3515 					p);
3516 				ret = -EINVAL;
3517 				goto out;
3518 			}
3519 			target->scsi_host->cmd_per_lun = token;
3520 			break;
3521 
3522 		case SRP_OPT_TARGET_CAN_QUEUE:
3523 			ret = match_int(args, &token);
3524 			if (ret) {
3525 				pr_warn("match_int() failed for max target_can_queue parameter '%s', Error %d\n",
3526 					p, ret);
3527 				goto out;
3528 			}
3529 			if (token < 1) {
3530 				pr_warn("bad max target_can_queue parameter '%s'\n",
3531 					p);
3532 				ret = -EINVAL;
3533 				goto out;
3534 			}
3535 			target->target_can_queue = token;
3536 			break;
3537 
3538 		case SRP_OPT_IO_CLASS:
3539 			ret = match_hex(args, &token);
3540 			if (ret) {
3541 				pr_warn("bad IO class parameter '%s'\n", p);
3542 				goto out;
3543 			}
3544 			if (token != SRP_REV10_IB_IO_CLASS &&
3545 			    token != SRP_REV16A_IB_IO_CLASS) {
3546 				pr_warn("unknown IO class parameter value %x specified (use %x or %x).\n",
3547 					token, SRP_REV10_IB_IO_CLASS,
3548 					SRP_REV16A_IB_IO_CLASS);
3549 				ret = -EINVAL;
3550 				goto out;
3551 			}
3552 			target->io_class = token;
3553 			break;
3554 
3555 		case SRP_OPT_INITIATOR_EXT:
3556 			p = match_strdup(args);
3557 			if (!p) {
3558 				ret = -ENOMEM;
3559 				goto out;
3560 			}
3561 			ret = kstrtoull(p, 16, &ull);
3562 			if (ret) {
3563 				pr_warn("bad initiator_ext value '%s'\n", p);
3564 				kfree(p);
3565 				goto out;
3566 			}
3567 			target->initiator_ext = cpu_to_be64(ull);
3568 			kfree(p);
3569 			break;
3570 
3571 		case SRP_OPT_CMD_SG_ENTRIES:
3572 			ret = match_int(args, &token);
3573 			if (ret) {
3574 				pr_warn("match_int() failed for max cmd_sg_entries parameter '%s', Error %d\n",
3575 					p, ret);
3576 				goto out;
3577 			}
3578 			if (token < 1 || token > 255) {
3579 				pr_warn("bad max cmd_sg_entries parameter '%s'\n",
3580 					p);
3581 				ret = -EINVAL;
3582 				goto out;
3583 			}
3584 			target->cmd_sg_cnt = token;
3585 			break;
3586 
3587 		case SRP_OPT_ALLOW_EXT_SG:
3588 			ret = match_int(args, &token);
3589 			if (ret) {
3590 				pr_warn("bad allow_ext_sg parameter '%s'\n", p);
3591 				goto out;
3592 			}
3593 			target->allow_ext_sg = !!token;
3594 			break;
3595 
3596 		case SRP_OPT_SG_TABLESIZE:
3597 			ret = match_int(args, &token);
3598 			if (ret) {
3599 				pr_warn("match_int() failed for max sg_tablesize parameter '%s', Error %d\n",
3600 					p, ret);
3601 				goto out;
3602 			}
3603 			if (token < 1 || token > SG_MAX_SEGMENTS) {
3604 				pr_warn("bad max sg_tablesize parameter '%s'\n",
3605 					p);
3606 				ret = -EINVAL;
3607 				goto out;
3608 			}
3609 			target->sg_tablesize = token;
3610 			break;
3611 
3612 		case SRP_OPT_COMP_VECTOR:
3613 			ret = match_int(args, &token);
3614 			if (ret) {
3615 				pr_warn("match_int() failed for comp_vector parameter '%s', Error %d\n",
3616 					p, ret);
3617 				goto out;
3618 			}
3619 			if (token < 0) {
3620 				pr_warn("bad comp_vector parameter '%s'\n", p);
3621 				ret = -EINVAL;
3622 				goto out;
3623 			}
3624 			target->comp_vector = token;
3625 			break;
3626 
3627 		case SRP_OPT_TL_RETRY_COUNT:
3628 			ret = match_int(args, &token);
3629 			if (ret) {
3630 				pr_warn("match_int() failed for tl_retry_count parameter '%s', Error %d\n",
3631 					p, ret);
3632 				goto out;
3633 			}
3634 			if (token < 2 || token > 7) {
3635 				pr_warn("bad tl_retry_count parameter '%s' (must be a number between 2 and 7)\n",
3636 					p);
3637 				ret = -EINVAL;
3638 				goto out;
3639 			}
3640 			target->tl_retry_count = token;
3641 			break;
3642 
3643 		case SRP_OPT_MAX_IT_IU_SIZE:
3644 			ret = match_int(args, &token);
3645 			if (ret) {
3646 				pr_warn("match_int() failed for max it_iu_size parameter '%s', Error %d\n",
3647 					p, ret);
3648 				goto out;
3649 			}
3650 			if (token < 0) {
3651 				pr_warn("bad maximum initiator to target IU size '%s'\n", p);
3652 				ret = -EINVAL;
3653 				goto out;
3654 			}
3655 			target->max_it_iu_size = token;
3656 			break;
3657 
3658 		case SRP_OPT_CH_COUNT:
3659 			ret = match_int(args, &token);
3660 			if (ret) {
3661 				pr_warn("match_int() failed for channel count parameter '%s', Error %d\n",
3662 					p, ret);
3663 				goto out;
3664 			}
3665 			if (token < 1) {
3666 				pr_warn("bad channel count %s\n", p);
3667 				ret = -EINVAL;
3668 				goto out;
3669 			}
3670 			target->ch_count = token;
3671 			break;
3672 
3673 		default:
3674 			pr_warn("unknown parameter or missing value '%s' in target creation request\n",
3675 				p);
3676 			ret = -EINVAL;
3677 			goto out;
3678 		}
3679 	}
3680 
3681 	for (i = 0; i < ARRAY_SIZE(srp_opt_mandatory); i++) {
3682 		if ((opt_mask & srp_opt_mandatory[i]) == srp_opt_mandatory[i]) {
3683 			ret = 0;
3684 			break;
3685 		}
3686 	}
3687 	if (ret)
3688 		pr_warn("target creation request is missing one or more parameters\n");
3689 
3690 	if (target->scsi_host->cmd_per_lun > target->scsi_host->can_queue
3691 	    && (opt_mask & SRP_OPT_MAX_CMD_PER_LUN))
3692 		pr_warn("cmd_per_lun = %d > queue_size = %d\n",
3693 			target->scsi_host->cmd_per_lun,
3694 			target->scsi_host->can_queue);
3695 
3696 out:
3697 	kfree(options);
3698 	return ret;
3699 }
3700 
3701 static ssize_t add_target_store(struct device *dev,
3702 				struct device_attribute *attr, const char *buf,
3703 				size_t count)
3704 {
3705 	struct srp_host *host =
3706 		container_of(dev, struct srp_host, dev);
3707 	struct Scsi_Host *target_host;
3708 	struct srp_target_port *target;
3709 	struct srp_rdma_ch *ch;
3710 	struct srp_device *srp_dev = host->srp_dev;
3711 	struct ib_device *ibdev = srp_dev->dev;
3712 	int ret, i, ch_idx;
3713 	unsigned int max_sectors_per_mr, mr_per_cmd = 0;
3714 	bool multich = false;
3715 	uint32_t max_iu_len;
3716 
3717 	target_host = scsi_host_alloc(&srp_template,
3718 				      sizeof (struct srp_target_port));
3719 	if (!target_host)
3720 		return -ENOMEM;
3721 
3722 	target_host->transportt  = ib_srp_transport_template;
3723 	target_host->max_channel = 0;
3724 	target_host->max_id      = 1;
3725 	target_host->max_lun     = -1LL;
3726 	target_host->max_cmd_len = sizeof ((struct srp_cmd *) (void *) 0L)->cdb;
3727 
3728 	if (ibdev->attrs.kernel_cap_flags & IBK_SG_GAPS_REG)
3729 		target_host->max_segment_size = ib_dma_max_seg_size(ibdev);
3730 	else
3731 		target_host->virt_boundary_mask = ~srp_dev->mr_page_mask;
3732 
3733 	target = host_to_target(target_host);
3734 
3735 	target->net		= to_net_ns(kobj_ns_grab_current(KOBJ_NS_TYPE_NET));
3736 	target->io_class	= SRP_REV16A_IB_IO_CLASS;
3737 	target->scsi_host	= target_host;
3738 	target->srp_host	= host;
3739 	target->lkey		= host->srp_dev->pd->local_dma_lkey;
3740 	target->global_rkey	= host->srp_dev->global_rkey;
3741 	target->cmd_sg_cnt	= cmd_sg_entries;
3742 	target->sg_tablesize	= indirect_sg_entries ? : cmd_sg_entries;
3743 	target->allow_ext_sg	= allow_ext_sg;
3744 	target->tl_retry_count	= 7;
3745 	target->queue_size	= SRP_DEFAULT_QUEUE_SIZE;
3746 
3747 	/*
3748 	 * Avoid that the SCSI host can be removed by srp_remove_target()
3749 	 * before this function returns.
3750 	 */
3751 	scsi_host_get(target->scsi_host);
3752 
3753 	ret = mutex_lock_interruptible(&host->add_target_mutex);
3754 	if (ret < 0)
3755 		goto put;
3756 
3757 	ret = srp_parse_options(target->net, buf, target);
3758 	if (ret)
3759 		goto out;
3760 
3761 	if (!srp_conn_unique(target->srp_host, target)) {
3762 		if (target->using_rdma_cm) {
3763 			shost_printk(KERN_INFO, target->scsi_host,
3764 				     PFX "Already connected to target port with id_ext=%016llx;ioc_guid=%016llx;dest=%pIS\n",
3765 				     be64_to_cpu(target->id_ext),
3766 				     be64_to_cpu(target->ioc_guid),
3767 				     &target->rdma_cm.dst);
3768 		} else {
3769 			shost_printk(KERN_INFO, target->scsi_host,
3770 				     PFX "Already connected to target port with id_ext=%016llx;ioc_guid=%016llx;initiator_ext=%016llx\n",
3771 				     be64_to_cpu(target->id_ext),
3772 				     be64_to_cpu(target->ioc_guid),
3773 				     be64_to_cpu(target->initiator_ext));
3774 		}
3775 		ret = -EEXIST;
3776 		goto out;
3777 	}
3778 
3779 	if (!srp_dev->has_fr && !target->allow_ext_sg &&
3780 	    target->cmd_sg_cnt < target->sg_tablesize) {
3781 		pr_warn("No MR pool and no external indirect descriptors, limiting sg_tablesize to cmd_sg_cnt\n");
3782 		target->sg_tablesize = target->cmd_sg_cnt;
3783 	}
3784 
3785 	if (srp_dev->use_fast_reg) {
3786 		bool gaps_reg = ibdev->attrs.kernel_cap_flags &
3787 				 IBK_SG_GAPS_REG;
3788 
3789 		max_sectors_per_mr = srp_dev->max_pages_per_mr <<
3790 				  (ilog2(srp_dev->mr_page_size) - 9);
3791 		if (!gaps_reg) {
3792 			/*
3793 			 * FR can only map one HCA page per entry. If the start
3794 			 * address is not aligned on a HCA page boundary two
3795 			 * entries will be used for the head and the tail
3796 			 * although these two entries combined contain at most
3797 			 * one HCA page of data. Hence the "+ 1" in the
3798 			 * calculation below.
3799 			 *
3800 			 * The indirect data buffer descriptor is contiguous
3801 			 * so the memory for that buffer will only be
3802 			 * registered if register_always is true. Hence add
3803 			 * one to mr_per_cmd if register_always has been set.
3804 			 */
3805 			mr_per_cmd = register_always +
3806 				(target->scsi_host->max_sectors + 1 +
3807 				 max_sectors_per_mr - 1) / max_sectors_per_mr;
3808 		} else {
3809 			mr_per_cmd = register_always +
3810 				(target->sg_tablesize +
3811 				 srp_dev->max_pages_per_mr - 1) /
3812 				srp_dev->max_pages_per_mr;
3813 		}
3814 		pr_debug("max_sectors = %u; max_pages_per_mr = %u; mr_page_size = %u; max_sectors_per_mr = %u; mr_per_cmd = %u\n",
3815 			 target->scsi_host->max_sectors, srp_dev->max_pages_per_mr, srp_dev->mr_page_size,
3816 			 max_sectors_per_mr, mr_per_cmd);
3817 	}
3818 
3819 	target_host->sg_tablesize = target->sg_tablesize;
3820 	target->mr_pool_size = target->scsi_host->can_queue * mr_per_cmd;
3821 	target->mr_per_cmd = mr_per_cmd;
3822 	target->indirect_size = target->sg_tablesize *
3823 				sizeof (struct srp_direct_buf);
3824 	max_iu_len = srp_max_it_iu_len(target->cmd_sg_cnt,
3825 				       srp_use_imm_data,
3826 				       target->max_it_iu_size);
3827 
3828 	INIT_WORK(&target->tl_err_work, srp_tl_err_work);
3829 	INIT_WORK(&target->remove_work, srp_remove_work);
3830 	spin_lock_init(&target->lock);
3831 	ret = rdma_query_gid(ibdev, host->port, 0, &target->sgid);
3832 	if (ret)
3833 		goto out;
3834 
3835 	ret = -ENOMEM;
3836 	if (target->ch_count == 0) {
3837 		target->ch_count =
3838 			min(ch_count ?:
3839 				max(4 * num_online_nodes(),
3840 				    ibdev->num_comp_vectors),
3841 				num_online_cpus());
3842 	}
3843 
3844 	target->ch = kzalloc_objs(*target->ch, target->ch_count);
3845 	if (!target->ch)
3846 		goto out;
3847 
3848 	for (ch_idx = 0; ch_idx < target->ch_count; ++ch_idx) {
3849 		ch = &target->ch[ch_idx];
3850 		ch->target = target;
3851 		ch->comp_vector = ch_idx % ibdev->num_comp_vectors;
3852 		spin_lock_init(&ch->lock);
3853 		INIT_LIST_HEAD(&ch->free_tx);
3854 		ret = srp_new_cm_id(ch);
3855 		if (ret)
3856 			goto err_disconnect;
3857 
3858 		ret = srp_create_ch_ib(ch);
3859 		if (ret)
3860 			goto err_disconnect;
3861 
3862 		ret = srp_connect_ch(ch, max_iu_len, multich);
3863 		if (ret) {
3864 			char dst[64];
3865 
3866 			if (target->using_rdma_cm)
3867 				snprintf(dst, sizeof(dst), "%pIS",
3868 					&target->rdma_cm.dst);
3869 			else
3870 				snprintf(dst, sizeof(dst), "%pI6",
3871 					target->ib_cm.orig_dgid.raw);
3872 			shost_printk(KERN_ERR, target->scsi_host,
3873 				PFX "Connection %d/%d to %s failed\n",
3874 				ch_idx,
3875 				target->ch_count, dst);
3876 			if (ch_idx == 0) {
3877 				goto free_ch;
3878 			} else {
3879 				srp_free_ch_ib(target, ch);
3880 				target->ch_count = ch - target->ch;
3881 				goto connected;
3882 			}
3883 		}
3884 		multich = true;
3885 	}
3886 
3887 connected:
3888 	target->scsi_host->nr_hw_queues = target->ch_count;
3889 
3890 	ret = srp_add_target(host, target);
3891 	if (ret)
3892 		goto err_disconnect;
3893 
3894 	if (target->state != SRP_TARGET_REMOVED) {
3895 		if (target->using_rdma_cm) {
3896 			shost_printk(KERN_DEBUG, target->scsi_host, PFX
3897 				     "new target: id_ext %016llx ioc_guid %016llx sgid %pI6 dest %pIS\n",
3898 				     be64_to_cpu(target->id_ext),
3899 				     be64_to_cpu(target->ioc_guid),
3900 				     target->sgid.raw, &target->rdma_cm.dst);
3901 		} else {
3902 			shost_printk(KERN_DEBUG, target->scsi_host, PFX
3903 				     "new target: id_ext %016llx ioc_guid %016llx pkey %04x service_id %016llx sgid %pI6 dgid %pI6\n",
3904 				     be64_to_cpu(target->id_ext),
3905 				     be64_to_cpu(target->ioc_guid),
3906 				     be16_to_cpu(target->ib_cm.pkey),
3907 				     be64_to_cpu(target->ib_cm.service_id),
3908 				     target->sgid.raw,
3909 				     target->ib_cm.orig_dgid.raw);
3910 		}
3911 	}
3912 
3913 	ret = count;
3914 
3915 out:
3916 	mutex_unlock(&host->add_target_mutex);
3917 
3918 put:
3919 	scsi_host_put(target->scsi_host);
3920 	if (ret < 0) {
3921 		/*
3922 		 * If a call to srp_remove_target() has not been scheduled,
3923 		 * drop the network namespace reference now that was obtained
3924 		 * earlier in this function.
3925 		 */
3926 		if (target->state != SRP_TARGET_REMOVED)
3927 			kobj_ns_drop(KOBJ_NS_TYPE_NET, to_ns_common(target->net));
3928 		scsi_host_put(target->scsi_host);
3929 	}
3930 
3931 	return ret;
3932 
3933 err_disconnect:
3934 	srp_disconnect_target(target);
3935 
3936 free_ch:
3937 	for (i = 0; i < target->ch_count; i++) {
3938 		ch = &target->ch[i];
3939 		srp_free_ch_ib(target, ch);
3940 	}
3941 
3942 	kfree(target->ch);
3943 	goto out;
3944 }
3945 
3946 static DEVICE_ATTR_WO(add_target);
3947 
3948 static ssize_t ibdev_show(struct device *dev, struct device_attribute *attr,
3949 			  char *buf)
3950 {
3951 	struct srp_host *host = container_of(dev, struct srp_host, dev);
3952 
3953 	return sysfs_emit(buf, "%s\n", dev_name(&host->srp_dev->dev->dev));
3954 }
3955 
3956 static DEVICE_ATTR_RO(ibdev);
3957 
3958 static ssize_t port_show(struct device *dev, struct device_attribute *attr,
3959 			 char *buf)
3960 {
3961 	struct srp_host *host = container_of(dev, struct srp_host, dev);
3962 
3963 	return sysfs_emit(buf, "%u\n", host->port);
3964 }
3965 
3966 static DEVICE_ATTR_RO(port);
3967 
3968 static struct attribute *srp_class_attrs[] = {
3969 	&dev_attr_add_target.attr,
3970 	&dev_attr_ibdev.attr,
3971 	&dev_attr_port.attr,
3972 	NULL
3973 };
3974 
3975 static struct srp_host *srp_add_port(struct srp_device *device, u32 port)
3976 {
3977 	struct srp_host *host;
3978 
3979 	host = kzalloc_obj(*host);
3980 	if (!host)
3981 		return NULL;
3982 
3983 	INIT_LIST_HEAD(&host->target_list);
3984 	spin_lock_init(&host->target_lock);
3985 	mutex_init(&host->add_target_mutex);
3986 	host->srp_dev = device;
3987 	host->port = port;
3988 
3989 	device_initialize(&host->dev);
3990 	host->dev.class = &srp_class;
3991 	host->dev.parent = device->dev->dev.parent;
3992 	if (dev_set_name(&host->dev, "srp-%s-%u", dev_name(&device->dev->dev),
3993 			 port))
3994 		goto put_host;
3995 	if (device_add(&host->dev))
3996 		goto put_host;
3997 
3998 	return host;
3999 
4000 put_host:
4001 	put_device(&host->dev);
4002 	return NULL;
4003 }
4004 
4005 static void srp_rename_dev(struct ib_device *device, void *client_data)
4006 {
4007 	struct srp_device *srp_dev = client_data;
4008 	struct srp_host *host, *tmp_host;
4009 
4010 	list_for_each_entry_safe(host, tmp_host, &srp_dev->dev_list, list) {
4011 		char name[IB_DEVICE_NAME_MAX + 8];
4012 
4013 		snprintf(name, sizeof(name), "srp-%s-%u",
4014 			 dev_name(&device->dev), host->port);
4015 		device_rename(&host->dev, name);
4016 	}
4017 }
4018 
4019 static int srp_add_one(struct ib_device *device)
4020 {
4021 	struct srp_device *srp_dev;
4022 	struct ib_device_attr *attr = &device->attrs;
4023 	struct srp_host *host;
4024 	int mr_page_shift;
4025 	u32 p;
4026 	u64 max_pages_per_mr;
4027 	unsigned int flags = 0;
4028 
4029 	srp_dev = kzalloc_obj(*srp_dev);
4030 	if (!srp_dev)
4031 		return -ENOMEM;
4032 
4033 	/*
4034 	 * Use the smallest page size supported by the HCA, down to a
4035 	 * minimum of 4096 bytes. We're unlikely to build large sglists
4036 	 * out of smaller entries.
4037 	 */
4038 	mr_page_shift		= max(12, ffs(attr->page_size_cap) - 1);
4039 	srp_dev->mr_page_size	= 1 << mr_page_shift;
4040 	srp_dev->mr_page_mask	= ~((u64) srp_dev->mr_page_size - 1);
4041 	max_pages_per_mr	= attr->max_mr_size;
4042 	do_div(max_pages_per_mr, srp_dev->mr_page_size);
4043 	pr_debug("%s: %llu / %u = %llu <> %u\n", __func__,
4044 		 attr->max_mr_size, srp_dev->mr_page_size,
4045 		 max_pages_per_mr, SRP_MAX_PAGES_PER_MR);
4046 	srp_dev->max_pages_per_mr = min_t(u64, SRP_MAX_PAGES_PER_MR,
4047 					  max_pages_per_mr);
4048 
4049 	srp_dev->has_fr = (attr->device_cap_flags &
4050 			   IB_DEVICE_MEM_MGT_EXTENSIONS);
4051 	if (!never_register && !srp_dev->has_fr)
4052 		dev_warn(&device->dev, "FR is not supported\n");
4053 	else if (!never_register &&
4054 		 attr->max_mr_size >= 2 * srp_dev->mr_page_size)
4055 		srp_dev->use_fast_reg = srp_dev->has_fr;
4056 
4057 	if (never_register || !register_always || !srp_dev->has_fr)
4058 		flags |= IB_PD_UNSAFE_GLOBAL_RKEY;
4059 
4060 	if (srp_dev->use_fast_reg) {
4061 		srp_dev->max_pages_per_mr =
4062 			min_t(u32, srp_dev->max_pages_per_mr,
4063 			      attr->max_fast_reg_page_list_len);
4064 	}
4065 	srp_dev->mr_max_size	= srp_dev->mr_page_size *
4066 				   srp_dev->max_pages_per_mr;
4067 	pr_debug("%s: mr_page_shift = %d, device->max_mr_size = %#llx, device->max_fast_reg_page_list_len = %u, max_pages_per_mr = %d, mr_max_size = %#x\n",
4068 		 dev_name(&device->dev), mr_page_shift, attr->max_mr_size,
4069 		 attr->max_fast_reg_page_list_len,
4070 		 srp_dev->max_pages_per_mr, srp_dev->mr_max_size);
4071 
4072 	INIT_LIST_HEAD(&srp_dev->dev_list);
4073 
4074 	srp_dev->dev = device;
4075 	srp_dev->pd  = ib_alloc_pd(device, flags);
4076 	if (IS_ERR(srp_dev->pd)) {
4077 		int ret = PTR_ERR(srp_dev->pd);
4078 
4079 		kfree(srp_dev);
4080 		return ret;
4081 	}
4082 
4083 	if (flags & IB_PD_UNSAFE_GLOBAL_RKEY) {
4084 		srp_dev->global_rkey = srp_dev->pd->unsafe_global_rkey;
4085 		WARN_ON_ONCE(srp_dev->global_rkey == 0);
4086 	}
4087 
4088 	rdma_for_each_port (device, p) {
4089 		host = srp_add_port(srp_dev, p);
4090 		if (host)
4091 			list_add_tail(&host->list, &srp_dev->dev_list);
4092 	}
4093 
4094 	ib_set_client_data(device, &srp_client, srp_dev);
4095 	return 0;
4096 }
4097 
4098 static void srp_remove_one(struct ib_device *device, void *client_data)
4099 {
4100 	struct srp_device *srp_dev;
4101 	struct srp_host *host, *tmp_host;
4102 	struct srp_target_port *target;
4103 
4104 	srp_dev = client_data;
4105 
4106 	list_for_each_entry_safe(host, tmp_host, &srp_dev->dev_list, list) {
4107 		/*
4108 		 * Remove the add_target sysfs entry so that no new target ports
4109 		 * can be created.
4110 		 */
4111 		device_del(&host->dev);
4112 
4113 		/*
4114 		 * Remove all target ports.
4115 		 */
4116 		spin_lock(&host->target_lock);
4117 		list_for_each_entry(target, &host->target_list, list)
4118 			srp_queue_remove_work(target);
4119 		spin_unlock(&host->target_lock);
4120 
4121 		/*
4122 		 * srp_queue_remove_work() queues a call to
4123 		 * srp_remove_target(). The latter function cancels
4124 		 * target->tl_err_work so waiting for the remove works to
4125 		 * finish is sufficient.
4126 		 */
4127 		flush_workqueue(srp_remove_wq);
4128 
4129 		put_device(&host->dev);
4130 	}
4131 
4132 	ib_dealloc_pd(srp_dev->pd);
4133 
4134 	kfree(srp_dev);
4135 }
4136 
4137 static struct srp_function_template ib_srp_transport_functions = {
4138 	.has_rport_state	 = true,
4139 	.reset_timer_if_blocked	 = true,
4140 	.reconnect_delay	 = &srp_reconnect_delay,
4141 	.fast_io_fail_tmo	 = &srp_fast_io_fail_tmo,
4142 	.dev_loss_tmo		 = &srp_dev_loss_tmo,
4143 	.reconnect		 = srp_rport_reconnect,
4144 	.rport_delete		 = srp_rport_delete,
4145 	.terminate_rport_io	 = srp_terminate_io,
4146 };
4147 
4148 static int __init srp_init_module(void)
4149 {
4150 	int ret;
4151 
4152 	BUILD_BUG_ON(sizeof(struct srp_aer_req) != 36);
4153 	BUILD_BUG_ON(sizeof(struct srp_cmd) != 48);
4154 	BUILD_BUG_ON(sizeof(struct srp_imm_buf) != 4);
4155 	BUILD_BUG_ON(sizeof(struct srp_indirect_buf) != 20);
4156 	BUILD_BUG_ON(sizeof(struct srp_login_req) != 64);
4157 	BUILD_BUG_ON(sizeof(struct srp_login_req_rdma) != 56);
4158 	BUILD_BUG_ON(sizeof(struct srp_rsp) != 36);
4159 
4160 	if (srp_sg_tablesize) {
4161 		pr_warn("srp_sg_tablesize is deprecated, please use cmd_sg_entries\n");
4162 		if (!cmd_sg_entries)
4163 			cmd_sg_entries = srp_sg_tablesize;
4164 	}
4165 
4166 	if (!cmd_sg_entries)
4167 		cmd_sg_entries = SRP_DEF_SG_TABLESIZE;
4168 
4169 	if (cmd_sg_entries > 255) {
4170 		pr_warn("Clamping cmd_sg_entries to 255\n");
4171 		cmd_sg_entries = 255;
4172 	}
4173 
4174 	if (!indirect_sg_entries)
4175 		indirect_sg_entries = cmd_sg_entries;
4176 	else if (indirect_sg_entries < cmd_sg_entries) {
4177 		pr_warn("Bumping up indirect_sg_entries to match cmd_sg_entries (%u)\n",
4178 			cmd_sg_entries);
4179 		indirect_sg_entries = cmd_sg_entries;
4180 	}
4181 
4182 	if (indirect_sg_entries > SG_MAX_SEGMENTS) {
4183 		pr_warn("Clamping indirect_sg_entries to %u\n",
4184 			SG_MAX_SEGMENTS);
4185 		indirect_sg_entries = SG_MAX_SEGMENTS;
4186 	}
4187 
4188 	srp_remove_wq = create_workqueue("srp_remove");
4189 	if (!srp_remove_wq) {
4190 		ret = -ENOMEM;
4191 		goto out;
4192 	}
4193 
4194 	ret = -ENOMEM;
4195 	ib_srp_transport_template =
4196 		srp_attach_transport(&ib_srp_transport_functions);
4197 	if (!ib_srp_transport_template)
4198 		goto destroy_wq;
4199 
4200 	ret = class_register(&srp_class);
4201 	if (ret) {
4202 		pr_err("couldn't register class infiniband_srp\n");
4203 		goto release_tr;
4204 	}
4205 
4206 	ib_sa_register_client(&srp_sa_client);
4207 
4208 	ret = ib_register_client(&srp_client);
4209 	if (ret) {
4210 		pr_err("couldn't register IB client\n");
4211 		goto unreg_sa;
4212 	}
4213 
4214 out:
4215 	return ret;
4216 
4217 unreg_sa:
4218 	ib_sa_unregister_client(&srp_sa_client);
4219 	class_unregister(&srp_class);
4220 
4221 release_tr:
4222 	srp_release_transport(ib_srp_transport_template);
4223 
4224 destroy_wq:
4225 	destroy_workqueue(srp_remove_wq);
4226 	goto out;
4227 }
4228 
4229 static void __exit srp_cleanup_module(void)
4230 {
4231 	ib_unregister_client(&srp_client);
4232 	ib_sa_unregister_client(&srp_sa_client);
4233 	class_unregister(&srp_class);
4234 	srp_release_transport(ib_srp_transport_template);
4235 	destroy_workqueue(srp_remove_wq);
4236 }
4237 
4238 module_init(srp_init_module);
4239 module_exit(srp_cleanup_module);
4240