xref: /linux/drivers/infiniband/ulp/srp/ib_srp.c (revision 148f9bb87745ed45f7a11b2cbd3bc0f017d5d257)
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) PFX fmt
34 
35 #include <linux/module.h>
36 #include <linux/init.h>
37 #include <linux/slab.h>
38 #include <linux/err.h>
39 #include <linux/string.h>
40 #include <linux/parser.h>
41 #include <linux/random.h>
42 #include <linux/jiffies.h>
43 
44 #include <linux/atomic.h>
45 
46 #include <scsi/scsi.h>
47 #include <scsi/scsi_device.h>
48 #include <scsi/scsi_dbg.h>
49 #include <scsi/srp.h>
50 #include <scsi/scsi_transport_srp.h>
51 
52 #include "ib_srp.h"
53 
54 #define DRV_NAME	"ib_srp"
55 #define PFX		DRV_NAME ": "
56 #define DRV_VERSION	"1.0"
57 #define DRV_RELDATE	"July 1, 2013"
58 
59 MODULE_AUTHOR("Roland Dreier");
60 MODULE_DESCRIPTION("InfiniBand SCSI RDMA Protocol initiator "
61 		   "v" DRV_VERSION " (" DRV_RELDATE ")");
62 MODULE_LICENSE("Dual BSD/GPL");
63 
64 static unsigned int srp_sg_tablesize;
65 static unsigned int cmd_sg_entries;
66 static unsigned int indirect_sg_entries;
67 static bool allow_ext_sg;
68 static int topspin_workarounds = 1;
69 
70 module_param(srp_sg_tablesize, uint, 0444);
71 MODULE_PARM_DESC(srp_sg_tablesize, "Deprecated name for cmd_sg_entries");
72 
73 module_param(cmd_sg_entries, uint, 0444);
74 MODULE_PARM_DESC(cmd_sg_entries,
75 		 "Default number of gather/scatter entries in the SRP command (default is 12, max 255)");
76 
77 module_param(indirect_sg_entries, uint, 0444);
78 MODULE_PARM_DESC(indirect_sg_entries,
79 		 "Default max number of gather/scatter entries (default is 12, max is " __stringify(SCSI_MAX_SG_CHAIN_SEGMENTS) ")");
80 
81 module_param(allow_ext_sg, bool, 0444);
82 MODULE_PARM_DESC(allow_ext_sg,
83 		  "Default behavior when there are more than cmd_sg_entries S/G entries after mapping; fails the request when false (default false)");
84 
85 module_param(topspin_workarounds, int, 0444);
86 MODULE_PARM_DESC(topspin_workarounds,
87 		 "Enable workarounds for Topspin/Cisco SRP target bugs if != 0");
88 
89 static void srp_add_one(struct ib_device *device);
90 static void srp_remove_one(struct ib_device *device);
91 static void srp_recv_completion(struct ib_cq *cq, void *target_ptr);
92 static void srp_send_completion(struct ib_cq *cq, void *target_ptr);
93 static int srp_cm_handler(struct ib_cm_id *cm_id, struct ib_cm_event *event);
94 
95 static struct scsi_transport_template *ib_srp_transport_template;
96 
97 static struct ib_client srp_client = {
98 	.name   = "srp",
99 	.add    = srp_add_one,
100 	.remove = srp_remove_one
101 };
102 
103 static struct ib_sa_client srp_sa_client;
104 
105 static inline struct srp_target_port *host_to_target(struct Scsi_Host *host)
106 {
107 	return (struct srp_target_port *) host->hostdata;
108 }
109 
110 static const char *srp_target_info(struct Scsi_Host *host)
111 {
112 	return host_to_target(host)->target_name;
113 }
114 
115 static int srp_target_is_topspin(struct srp_target_port *target)
116 {
117 	static const u8 topspin_oui[3] = { 0x00, 0x05, 0xad };
118 	static const u8 cisco_oui[3]   = { 0x00, 0x1b, 0x0d };
119 
120 	return topspin_workarounds &&
121 		(!memcmp(&target->ioc_guid, topspin_oui, sizeof topspin_oui) ||
122 		 !memcmp(&target->ioc_guid, cisco_oui, sizeof cisco_oui));
123 }
124 
125 static struct srp_iu *srp_alloc_iu(struct srp_host *host, size_t size,
126 				   gfp_t gfp_mask,
127 				   enum dma_data_direction direction)
128 {
129 	struct srp_iu *iu;
130 
131 	iu = kmalloc(sizeof *iu, gfp_mask);
132 	if (!iu)
133 		goto out;
134 
135 	iu->buf = kzalloc(size, gfp_mask);
136 	if (!iu->buf)
137 		goto out_free_iu;
138 
139 	iu->dma = ib_dma_map_single(host->srp_dev->dev, iu->buf, size,
140 				    direction);
141 	if (ib_dma_mapping_error(host->srp_dev->dev, iu->dma))
142 		goto out_free_buf;
143 
144 	iu->size      = size;
145 	iu->direction = direction;
146 
147 	return iu;
148 
149 out_free_buf:
150 	kfree(iu->buf);
151 out_free_iu:
152 	kfree(iu);
153 out:
154 	return NULL;
155 }
156 
157 static void srp_free_iu(struct srp_host *host, struct srp_iu *iu)
158 {
159 	if (!iu)
160 		return;
161 
162 	ib_dma_unmap_single(host->srp_dev->dev, iu->dma, iu->size,
163 			    iu->direction);
164 	kfree(iu->buf);
165 	kfree(iu);
166 }
167 
168 static void srp_qp_event(struct ib_event *event, void *context)
169 {
170 	pr_debug("QP event %d\n", event->event);
171 }
172 
173 static int srp_init_qp(struct srp_target_port *target,
174 		       struct ib_qp *qp)
175 {
176 	struct ib_qp_attr *attr;
177 	int ret;
178 
179 	attr = kmalloc(sizeof *attr, GFP_KERNEL);
180 	if (!attr)
181 		return -ENOMEM;
182 
183 	ret = ib_find_pkey(target->srp_host->srp_dev->dev,
184 			   target->srp_host->port,
185 			   be16_to_cpu(target->path.pkey),
186 			   &attr->pkey_index);
187 	if (ret)
188 		goto out;
189 
190 	attr->qp_state        = IB_QPS_INIT;
191 	attr->qp_access_flags = (IB_ACCESS_REMOTE_READ |
192 				    IB_ACCESS_REMOTE_WRITE);
193 	attr->port_num        = target->srp_host->port;
194 
195 	ret = ib_modify_qp(qp, attr,
196 			   IB_QP_STATE		|
197 			   IB_QP_PKEY_INDEX	|
198 			   IB_QP_ACCESS_FLAGS	|
199 			   IB_QP_PORT);
200 
201 out:
202 	kfree(attr);
203 	return ret;
204 }
205 
206 static int srp_new_cm_id(struct srp_target_port *target)
207 {
208 	struct ib_cm_id *new_cm_id;
209 
210 	new_cm_id = ib_create_cm_id(target->srp_host->srp_dev->dev,
211 				    srp_cm_handler, target);
212 	if (IS_ERR(new_cm_id))
213 		return PTR_ERR(new_cm_id);
214 
215 	if (target->cm_id)
216 		ib_destroy_cm_id(target->cm_id);
217 	target->cm_id = new_cm_id;
218 
219 	return 0;
220 }
221 
222 static int srp_create_target_ib(struct srp_target_port *target)
223 {
224 	struct ib_qp_init_attr *init_attr;
225 	struct ib_cq *recv_cq, *send_cq;
226 	struct ib_qp *qp;
227 	int ret;
228 
229 	init_attr = kzalloc(sizeof *init_attr, GFP_KERNEL);
230 	if (!init_attr)
231 		return -ENOMEM;
232 
233 	recv_cq = ib_create_cq(target->srp_host->srp_dev->dev,
234 			       srp_recv_completion, NULL, target, SRP_RQ_SIZE,
235 			       target->comp_vector);
236 	if (IS_ERR(recv_cq)) {
237 		ret = PTR_ERR(recv_cq);
238 		goto err;
239 	}
240 
241 	send_cq = ib_create_cq(target->srp_host->srp_dev->dev,
242 			       srp_send_completion, NULL, target, SRP_SQ_SIZE,
243 			       target->comp_vector);
244 	if (IS_ERR(send_cq)) {
245 		ret = PTR_ERR(send_cq);
246 		goto err_recv_cq;
247 	}
248 
249 	ib_req_notify_cq(recv_cq, IB_CQ_NEXT_COMP);
250 
251 	init_attr->event_handler       = srp_qp_event;
252 	init_attr->cap.max_send_wr     = SRP_SQ_SIZE;
253 	init_attr->cap.max_recv_wr     = SRP_RQ_SIZE;
254 	init_attr->cap.max_recv_sge    = 1;
255 	init_attr->cap.max_send_sge    = 1;
256 	init_attr->sq_sig_type         = IB_SIGNAL_ALL_WR;
257 	init_attr->qp_type             = IB_QPT_RC;
258 	init_attr->send_cq             = send_cq;
259 	init_attr->recv_cq             = recv_cq;
260 
261 	qp = ib_create_qp(target->srp_host->srp_dev->pd, init_attr);
262 	if (IS_ERR(qp)) {
263 		ret = PTR_ERR(qp);
264 		goto err_send_cq;
265 	}
266 
267 	ret = srp_init_qp(target, qp);
268 	if (ret)
269 		goto err_qp;
270 
271 	if (target->qp)
272 		ib_destroy_qp(target->qp);
273 	if (target->recv_cq)
274 		ib_destroy_cq(target->recv_cq);
275 	if (target->send_cq)
276 		ib_destroy_cq(target->send_cq);
277 
278 	target->qp = qp;
279 	target->recv_cq = recv_cq;
280 	target->send_cq = send_cq;
281 
282 	kfree(init_attr);
283 	return 0;
284 
285 err_qp:
286 	ib_destroy_qp(qp);
287 
288 err_send_cq:
289 	ib_destroy_cq(send_cq);
290 
291 err_recv_cq:
292 	ib_destroy_cq(recv_cq);
293 
294 err:
295 	kfree(init_attr);
296 	return ret;
297 }
298 
299 static void srp_free_target_ib(struct srp_target_port *target)
300 {
301 	int i;
302 
303 	ib_destroy_qp(target->qp);
304 	ib_destroy_cq(target->send_cq);
305 	ib_destroy_cq(target->recv_cq);
306 
307 	target->qp = NULL;
308 	target->send_cq = target->recv_cq = NULL;
309 
310 	for (i = 0; i < SRP_RQ_SIZE; ++i)
311 		srp_free_iu(target->srp_host, target->rx_ring[i]);
312 	for (i = 0; i < SRP_SQ_SIZE; ++i)
313 		srp_free_iu(target->srp_host, target->tx_ring[i]);
314 }
315 
316 static void srp_path_rec_completion(int status,
317 				    struct ib_sa_path_rec *pathrec,
318 				    void *target_ptr)
319 {
320 	struct srp_target_port *target = target_ptr;
321 
322 	target->status = status;
323 	if (status)
324 		shost_printk(KERN_ERR, target->scsi_host,
325 			     PFX "Got failed path rec status %d\n", status);
326 	else
327 		target->path = *pathrec;
328 	complete(&target->done);
329 }
330 
331 static int srp_lookup_path(struct srp_target_port *target)
332 {
333 	target->path.numb_path = 1;
334 
335 	init_completion(&target->done);
336 
337 	target->path_query_id = ib_sa_path_rec_get(&srp_sa_client,
338 						   target->srp_host->srp_dev->dev,
339 						   target->srp_host->port,
340 						   &target->path,
341 						   IB_SA_PATH_REC_SERVICE_ID	|
342 						   IB_SA_PATH_REC_DGID		|
343 						   IB_SA_PATH_REC_SGID		|
344 						   IB_SA_PATH_REC_NUMB_PATH	|
345 						   IB_SA_PATH_REC_PKEY,
346 						   SRP_PATH_REC_TIMEOUT_MS,
347 						   GFP_KERNEL,
348 						   srp_path_rec_completion,
349 						   target, &target->path_query);
350 	if (target->path_query_id < 0)
351 		return target->path_query_id;
352 
353 	wait_for_completion(&target->done);
354 
355 	if (target->status < 0)
356 		shost_printk(KERN_WARNING, target->scsi_host,
357 			     PFX "Path record query failed\n");
358 
359 	return target->status;
360 }
361 
362 static int srp_send_req(struct srp_target_port *target)
363 {
364 	struct {
365 		struct ib_cm_req_param param;
366 		struct srp_login_req   priv;
367 	} *req = NULL;
368 	int status;
369 
370 	req = kzalloc(sizeof *req, GFP_KERNEL);
371 	if (!req)
372 		return -ENOMEM;
373 
374 	req->param.primary_path 	      = &target->path;
375 	req->param.alternate_path 	      = NULL;
376 	req->param.service_id 		      = target->service_id;
377 	req->param.qp_num 		      = target->qp->qp_num;
378 	req->param.qp_type 		      = target->qp->qp_type;
379 	req->param.private_data 	      = &req->priv;
380 	req->param.private_data_len 	      = sizeof req->priv;
381 	req->param.flow_control 	      = 1;
382 
383 	get_random_bytes(&req->param.starting_psn, 4);
384 	req->param.starting_psn 	     &= 0xffffff;
385 
386 	/*
387 	 * Pick some arbitrary defaults here; we could make these
388 	 * module parameters if anyone cared about setting them.
389 	 */
390 	req->param.responder_resources	      = 4;
391 	req->param.remote_cm_response_timeout = 20;
392 	req->param.local_cm_response_timeout  = 20;
393 	req->param.retry_count 		      = 7;
394 	req->param.rnr_retry_count 	      = 7;
395 	req->param.max_cm_retries 	      = 15;
396 
397 	req->priv.opcode     	= SRP_LOGIN_REQ;
398 	req->priv.tag        	= 0;
399 	req->priv.req_it_iu_len = cpu_to_be32(target->max_iu_len);
400 	req->priv.req_buf_fmt 	= cpu_to_be16(SRP_BUF_FORMAT_DIRECT |
401 					      SRP_BUF_FORMAT_INDIRECT);
402 	/*
403 	 * In the published SRP specification (draft rev. 16a), the
404 	 * port identifier format is 8 bytes of ID extension followed
405 	 * by 8 bytes of GUID.  Older drafts put the two halves in the
406 	 * opposite order, so that the GUID comes first.
407 	 *
408 	 * Targets conforming to these obsolete drafts can be
409 	 * recognized by the I/O Class they report.
410 	 */
411 	if (target->io_class == SRP_REV10_IB_IO_CLASS) {
412 		memcpy(req->priv.initiator_port_id,
413 		       &target->path.sgid.global.interface_id, 8);
414 		memcpy(req->priv.initiator_port_id + 8,
415 		       &target->initiator_ext, 8);
416 		memcpy(req->priv.target_port_id,     &target->ioc_guid, 8);
417 		memcpy(req->priv.target_port_id + 8, &target->id_ext, 8);
418 	} else {
419 		memcpy(req->priv.initiator_port_id,
420 		       &target->initiator_ext, 8);
421 		memcpy(req->priv.initiator_port_id + 8,
422 		       &target->path.sgid.global.interface_id, 8);
423 		memcpy(req->priv.target_port_id,     &target->id_ext, 8);
424 		memcpy(req->priv.target_port_id + 8, &target->ioc_guid, 8);
425 	}
426 
427 	/*
428 	 * Topspin/Cisco SRP targets will reject our login unless we
429 	 * zero out the first 8 bytes of our initiator port ID and set
430 	 * the second 8 bytes to the local node GUID.
431 	 */
432 	if (srp_target_is_topspin(target)) {
433 		shost_printk(KERN_DEBUG, target->scsi_host,
434 			     PFX "Topspin/Cisco initiator port ID workaround "
435 			     "activated for target GUID %016llx\n",
436 			     (unsigned long long) be64_to_cpu(target->ioc_guid));
437 		memset(req->priv.initiator_port_id, 0, 8);
438 		memcpy(req->priv.initiator_port_id + 8,
439 		       &target->srp_host->srp_dev->dev->node_guid, 8);
440 	}
441 
442 	status = ib_send_cm_req(target->cm_id, &req->param);
443 
444 	kfree(req);
445 
446 	return status;
447 }
448 
449 static bool srp_queue_remove_work(struct srp_target_port *target)
450 {
451 	bool changed = false;
452 
453 	spin_lock_irq(&target->lock);
454 	if (target->state != SRP_TARGET_REMOVED) {
455 		target->state = SRP_TARGET_REMOVED;
456 		changed = true;
457 	}
458 	spin_unlock_irq(&target->lock);
459 
460 	if (changed)
461 		queue_work(system_long_wq, &target->remove_work);
462 
463 	return changed;
464 }
465 
466 static bool srp_change_conn_state(struct srp_target_port *target,
467 				  bool connected)
468 {
469 	bool changed = false;
470 
471 	spin_lock_irq(&target->lock);
472 	if (target->connected != connected) {
473 		target->connected = connected;
474 		changed = true;
475 	}
476 	spin_unlock_irq(&target->lock);
477 
478 	return changed;
479 }
480 
481 static void srp_disconnect_target(struct srp_target_port *target)
482 {
483 	if (srp_change_conn_state(target, false)) {
484 		/* XXX should send SRP_I_LOGOUT request */
485 
486 		if (ib_send_cm_dreq(target->cm_id, NULL, 0)) {
487 			shost_printk(KERN_DEBUG, target->scsi_host,
488 				     PFX "Sending CM DREQ failed\n");
489 		}
490 	}
491 }
492 
493 static void srp_free_req_data(struct srp_target_port *target)
494 {
495 	struct ib_device *ibdev = target->srp_host->srp_dev->dev;
496 	struct srp_request *req;
497 	int i;
498 
499 	for (i = 0, req = target->req_ring; i < SRP_CMD_SQ_SIZE; ++i, ++req) {
500 		kfree(req->fmr_list);
501 		kfree(req->map_page);
502 		if (req->indirect_dma_addr) {
503 			ib_dma_unmap_single(ibdev, req->indirect_dma_addr,
504 					    target->indirect_size,
505 					    DMA_TO_DEVICE);
506 		}
507 		kfree(req->indirect_desc);
508 	}
509 }
510 
511 /**
512  * srp_del_scsi_host_attr() - Remove attributes defined in the host template.
513  * @shost: SCSI host whose attributes to remove from sysfs.
514  *
515  * Note: Any attributes defined in the host template and that did not exist
516  * before invocation of this function will be ignored.
517  */
518 static void srp_del_scsi_host_attr(struct Scsi_Host *shost)
519 {
520 	struct device_attribute **attr;
521 
522 	for (attr = shost->hostt->shost_attrs; attr && *attr; ++attr)
523 		device_remove_file(&shost->shost_dev, *attr);
524 }
525 
526 static void srp_remove_target(struct srp_target_port *target)
527 {
528 	WARN_ON_ONCE(target->state != SRP_TARGET_REMOVED);
529 
530 	srp_del_scsi_host_attr(target->scsi_host);
531 	srp_remove_host(target->scsi_host);
532 	scsi_remove_host(target->scsi_host);
533 	srp_disconnect_target(target);
534 	ib_destroy_cm_id(target->cm_id);
535 	srp_free_target_ib(target);
536 	srp_free_req_data(target);
537 	scsi_host_put(target->scsi_host);
538 }
539 
540 static void srp_remove_work(struct work_struct *work)
541 {
542 	struct srp_target_port *target =
543 		container_of(work, struct srp_target_port, remove_work);
544 
545 	WARN_ON_ONCE(target->state != SRP_TARGET_REMOVED);
546 
547 	srp_remove_target(target);
548 
549 	spin_lock(&target->srp_host->target_lock);
550 	list_del(&target->list);
551 	spin_unlock(&target->srp_host->target_lock);
552 }
553 
554 static void srp_rport_delete(struct srp_rport *rport)
555 {
556 	struct srp_target_port *target = rport->lld_data;
557 
558 	srp_queue_remove_work(target);
559 }
560 
561 static int srp_connect_target(struct srp_target_port *target)
562 {
563 	int retries = 3;
564 	int ret;
565 
566 	WARN_ON_ONCE(target->connected);
567 
568 	target->qp_in_error = false;
569 
570 	ret = srp_lookup_path(target);
571 	if (ret)
572 		return ret;
573 
574 	while (1) {
575 		init_completion(&target->done);
576 		ret = srp_send_req(target);
577 		if (ret)
578 			return ret;
579 		wait_for_completion(&target->done);
580 
581 		/*
582 		 * The CM event handling code will set status to
583 		 * SRP_PORT_REDIRECT if we get a port redirect REJ
584 		 * back, or SRP_DLID_REDIRECT if we get a lid/qp
585 		 * redirect REJ back.
586 		 */
587 		switch (target->status) {
588 		case 0:
589 			srp_change_conn_state(target, true);
590 			return 0;
591 
592 		case SRP_PORT_REDIRECT:
593 			ret = srp_lookup_path(target);
594 			if (ret)
595 				return ret;
596 			break;
597 
598 		case SRP_DLID_REDIRECT:
599 			break;
600 
601 		case SRP_STALE_CONN:
602 			/* Our current CM id was stale, and is now in timewait.
603 			 * Try to reconnect with a new one.
604 			 */
605 			if (!retries-- || srp_new_cm_id(target)) {
606 				shost_printk(KERN_ERR, target->scsi_host, PFX
607 					     "giving up on stale connection\n");
608 				target->status = -ECONNRESET;
609 				return target->status;
610 			}
611 
612 			shost_printk(KERN_ERR, target->scsi_host, PFX
613 				     "retrying stale connection\n");
614 			break;
615 
616 		default:
617 			return target->status;
618 		}
619 	}
620 }
621 
622 static void srp_unmap_data(struct scsi_cmnd *scmnd,
623 			   struct srp_target_port *target,
624 			   struct srp_request *req)
625 {
626 	struct ib_device *ibdev = target->srp_host->srp_dev->dev;
627 	struct ib_pool_fmr **pfmr;
628 
629 	if (!scsi_sglist(scmnd) ||
630 	    (scmnd->sc_data_direction != DMA_TO_DEVICE &&
631 	     scmnd->sc_data_direction != DMA_FROM_DEVICE))
632 		return;
633 
634 	pfmr = req->fmr_list;
635 	while (req->nfmr--)
636 		ib_fmr_pool_unmap(*pfmr++);
637 
638 	ib_dma_unmap_sg(ibdev, scsi_sglist(scmnd), scsi_sg_count(scmnd),
639 			scmnd->sc_data_direction);
640 }
641 
642 /**
643  * srp_claim_req - Take ownership of the scmnd associated with a request.
644  * @target: SRP target port.
645  * @req: SRP request.
646  * @scmnd: If NULL, take ownership of @req->scmnd. If not NULL, only take
647  *         ownership of @req->scmnd if it equals @scmnd.
648  *
649  * Return value:
650  * Either NULL or a pointer to the SCSI command the caller became owner of.
651  */
652 static struct scsi_cmnd *srp_claim_req(struct srp_target_port *target,
653 				       struct srp_request *req,
654 				       struct scsi_cmnd *scmnd)
655 {
656 	unsigned long flags;
657 
658 	spin_lock_irqsave(&target->lock, flags);
659 	if (!scmnd) {
660 		scmnd = req->scmnd;
661 		req->scmnd = NULL;
662 	} else if (req->scmnd == scmnd) {
663 		req->scmnd = NULL;
664 	} else {
665 		scmnd = NULL;
666 	}
667 	spin_unlock_irqrestore(&target->lock, flags);
668 
669 	return scmnd;
670 }
671 
672 /**
673  * srp_free_req() - Unmap data and add request to the free request list.
674  */
675 static void srp_free_req(struct srp_target_port *target,
676 			 struct srp_request *req, struct scsi_cmnd *scmnd,
677 			 s32 req_lim_delta)
678 {
679 	unsigned long flags;
680 
681 	srp_unmap_data(scmnd, target, req);
682 
683 	spin_lock_irqsave(&target->lock, flags);
684 	target->req_lim += req_lim_delta;
685 	list_add_tail(&req->list, &target->free_reqs);
686 	spin_unlock_irqrestore(&target->lock, flags);
687 }
688 
689 static void srp_reset_req(struct srp_target_port *target, struct srp_request *req)
690 {
691 	struct scsi_cmnd *scmnd = srp_claim_req(target, req, NULL);
692 
693 	if (scmnd) {
694 		srp_free_req(target, req, scmnd, 0);
695 		scmnd->result = DID_RESET << 16;
696 		scmnd->scsi_done(scmnd);
697 	}
698 }
699 
700 static int srp_reconnect_target(struct srp_target_port *target)
701 {
702 	struct Scsi_Host *shost = target->scsi_host;
703 	int i, ret;
704 
705 	scsi_target_block(&shost->shost_gendev);
706 
707 	srp_disconnect_target(target);
708 	/*
709 	 * Now get a new local CM ID so that we avoid confusing the target in
710 	 * case things are really fouled up. Doing so also ensures that all CM
711 	 * callbacks will have finished before a new QP is allocated.
712 	 */
713 	ret = srp_new_cm_id(target);
714 	/*
715 	 * Whether or not creating a new CM ID succeeded, create a new
716 	 * QP. This guarantees that all completion callback function
717 	 * invocations have finished before request resetting starts.
718 	 */
719 	if (ret == 0)
720 		ret = srp_create_target_ib(target);
721 	else
722 		srp_create_target_ib(target);
723 
724 	for (i = 0; i < SRP_CMD_SQ_SIZE; ++i) {
725 		struct srp_request *req = &target->req_ring[i];
726 		if (req->scmnd)
727 			srp_reset_req(target, req);
728 	}
729 
730 	INIT_LIST_HEAD(&target->free_tx);
731 	for (i = 0; i < SRP_SQ_SIZE; ++i)
732 		list_add(&target->tx_ring[i]->list, &target->free_tx);
733 
734 	if (ret == 0)
735 		ret = srp_connect_target(target);
736 
737 	scsi_target_unblock(&shost->shost_gendev, ret == 0 ? SDEV_RUNNING :
738 			    SDEV_TRANSPORT_OFFLINE);
739 	target->transport_offline = !!ret;
740 
741 	if (ret)
742 		goto err;
743 
744 	shost_printk(KERN_INFO, target->scsi_host, PFX "reconnect succeeded\n");
745 
746 	return ret;
747 
748 err:
749 	shost_printk(KERN_ERR, target->scsi_host,
750 		     PFX "reconnect failed (%d), removing target port.\n", ret);
751 
752 	/*
753 	 * We couldn't reconnect, so kill our target port off.
754 	 * However, we have to defer the real removal because we
755 	 * are in the context of the SCSI error handler now, which
756 	 * will deadlock if we call scsi_remove_host().
757 	 */
758 	srp_queue_remove_work(target);
759 
760 	return ret;
761 }
762 
763 static void srp_map_desc(struct srp_map_state *state, dma_addr_t dma_addr,
764 			 unsigned int dma_len, u32 rkey)
765 {
766 	struct srp_direct_buf *desc = state->desc;
767 
768 	desc->va = cpu_to_be64(dma_addr);
769 	desc->key = cpu_to_be32(rkey);
770 	desc->len = cpu_to_be32(dma_len);
771 
772 	state->total_len += dma_len;
773 	state->desc++;
774 	state->ndesc++;
775 }
776 
777 static int srp_map_finish_fmr(struct srp_map_state *state,
778 			      struct srp_target_port *target)
779 {
780 	struct srp_device *dev = target->srp_host->srp_dev;
781 	struct ib_pool_fmr *fmr;
782 	u64 io_addr = 0;
783 
784 	if (!state->npages)
785 		return 0;
786 
787 	if (state->npages == 1) {
788 		srp_map_desc(state, state->base_dma_addr, state->fmr_len,
789 			     target->rkey);
790 		state->npages = state->fmr_len = 0;
791 		return 0;
792 	}
793 
794 	fmr = ib_fmr_pool_map_phys(dev->fmr_pool, state->pages,
795 				   state->npages, io_addr);
796 	if (IS_ERR(fmr))
797 		return PTR_ERR(fmr);
798 
799 	*state->next_fmr++ = fmr;
800 	state->nfmr++;
801 
802 	srp_map_desc(state, 0, state->fmr_len, fmr->fmr->rkey);
803 	state->npages = state->fmr_len = 0;
804 	return 0;
805 }
806 
807 static void srp_map_update_start(struct srp_map_state *state,
808 				 struct scatterlist *sg, int sg_index,
809 				 dma_addr_t dma_addr)
810 {
811 	state->unmapped_sg = sg;
812 	state->unmapped_index = sg_index;
813 	state->unmapped_addr = dma_addr;
814 }
815 
816 static int srp_map_sg_entry(struct srp_map_state *state,
817 			    struct srp_target_port *target,
818 			    struct scatterlist *sg, int sg_index,
819 			    int use_fmr)
820 {
821 	struct srp_device *dev = target->srp_host->srp_dev;
822 	struct ib_device *ibdev = dev->dev;
823 	dma_addr_t dma_addr = ib_sg_dma_address(ibdev, sg);
824 	unsigned int dma_len = ib_sg_dma_len(ibdev, sg);
825 	unsigned int len;
826 	int ret;
827 
828 	if (!dma_len)
829 		return 0;
830 
831 	if (use_fmr == SRP_MAP_NO_FMR) {
832 		/* Once we're in direct map mode for a request, we don't
833 		 * go back to FMR mode, so no need to update anything
834 		 * other than the descriptor.
835 		 */
836 		srp_map_desc(state, dma_addr, dma_len, target->rkey);
837 		return 0;
838 	}
839 
840 	/* If we start at an offset into the FMR page, don't merge into
841 	 * the current FMR. Finish it out, and use the kernel's MR for this
842 	 * sg entry. This is to avoid potential bugs on some SRP targets
843 	 * that were never quite defined, but went away when the initiator
844 	 * avoided using FMR on such page fragments.
845 	 */
846 	if (dma_addr & ~dev->fmr_page_mask || dma_len > dev->fmr_max_size) {
847 		ret = srp_map_finish_fmr(state, target);
848 		if (ret)
849 			return ret;
850 
851 		srp_map_desc(state, dma_addr, dma_len, target->rkey);
852 		srp_map_update_start(state, NULL, 0, 0);
853 		return 0;
854 	}
855 
856 	/* If this is the first sg to go into the FMR, save our position.
857 	 * We need to know the first unmapped entry, its index, and the
858 	 * first unmapped address within that entry to be able to restart
859 	 * mapping after an error.
860 	 */
861 	if (!state->unmapped_sg)
862 		srp_map_update_start(state, sg, sg_index, dma_addr);
863 
864 	while (dma_len) {
865 		if (state->npages == SRP_FMR_SIZE) {
866 			ret = srp_map_finish_fmr(state, target);
867 			if (ret)
868 				return ret;
869 
870 			srp_map_update_start(state, sg, sg_index, dma_addr);
871 		}
872 
873 		len = min_t(unsigned int, dma_len, dev->fmr_page_size);
874 
875 		if (!state->npages)
876 			state->base_dma_addr = dma_addr;
877 		state->pages[state->npages++] = dma_addr;
878 		state->fmr_len += len;
879 		dma_addr += len;
880 		dma_len -= len;
881 	}
882 
883 	/* If the last entry of the FMR wasn't a full page, then we need to
884 	 * close it out and start a new one -- we can only merge at page
885 	 * boundries.
886 	 */
887 	ret = 0;
888 	if (len != dev->fmr_page_size) {
889 		ret = srp_map_finish_fmr(state, target);
890 		if (!ret)
891 			srp_map_update_start(state, NULL, 0, 0);
892 	}
893 	return ret;
894 }
895 
896 static int srp_map_data(struct scsi_cmnd *scmnd, struct srp_target_port *target,
897 			struct srp_request *req)
898 {
899 	struct scatterlist *scat, *sg;
900 	struct srp_cmd *cmd = req->cmd->buf;
901 	int i, len, nents, count, use_fmr;
902 	struct srp_device *dev;
903 	struct ib_device *ibdev;
904 	struct srp_map_state state;
905 	struct srp_indirect_buf *indirect_hdr;
906 	u32 table_len;
907 	u8 fmt;
908 
909 	if (!scsi_sglist(scmnd) || scmnd->sc_data_direction == DMA_NONE)
910 		return sizeof (struct srp_cmd);
911 
912 	if (scmnd->sc_data_direction != DMA_FROM_DEVICE &&
913 	    scmnd->sc_data_direction != DMA_TO_DEVICE) {
914 		shost_printk(KERN_WARNING, target->scsi_host,
915 			     PFX "Unhandled data direction %d\n",
916 			     scmnd->sc_data_direction);
917 		return -EINVAL;
918 	}
919 
920 	nents = scsi_sg_count(scmnd);
921 	scat  = scsi_sglist(scmnd);
922 
923 	dev = target->srp_host->srp_dev;
924 	ibdev = dev->dev;
925 
926 	count = ib_dma_map_sg(ibdev, scat, nents, scmnd->sc_data_direction);
927 	if (unlikely(count == 0))
928 		return -EIO;
929 
930 	fmt = SRP_DATA_DESC_DIRECT;
931 	len = sizeof (struct srp_cmd) +	sizeof (struct srp_direct_buf);
932 
933 	if (count == 1) {
934 		/*
935 		 * The midlayer only generated a single gather/scatter
936 		 * entry, or DMA mapping coalesced everything to a
937 		 * single entry.  So a direct descriptor along with
938 		 * the DMA MR suffices.
939 		 */
940 		struct srp_direct_buf *buf = (void *) cmd->add_data;
941 
942 		buf->va  = cpu_to_be64(ib_sg_dma_address(ibdev, scat));
943 		buf->key = cpu_to_be32(target->rkey);
944 		buf->len = cpu_to_be32(ib_sg_dma_len(ibdev, scat));
945 
946 		req->nfmr = 0;
947 		goto map_complete;
948 	}
949 
950 	/* We have more than one scatter/gather entry, so build our indirect
951 	 * descriptor table, trying to merge as many entries with FMR as we
952 	 * can.
953 	 */
954 	indirect_hdr = (void *) cmd->add_data;
955 
956 	ib_dma_sync_single_for_cpu(ibdev, req->indirect_dma_addr,
957 				   target->indirect_size, DMA_TO_DEVICE);
958 
959 	memset(&state, 0, sizeof(state));
960 	state.desc	= req->indirect_desc;
961 	state.pages	= req->map_page;
962 	state.next_fmr	= req->fmr_list;
963 
964 	use_fmr = dev->fmr_pool ? SRP_MAP_ALLOW_FMR : SRP_MAP_NO_FMR;
965 
966 	for_each_sg(scat, sg, count, i) {
967 		if (srp_map_sg_entry(&state, target, sg, i, use_fmr)) {
968 			/* FMR mapping failed, so backtrack to the first
969 			 * unmapped entry and continue on without using FMR.
970 			 */
971 			dma_addr_t dma_addr;
972 			unsigned int dma_len;
973 
974 backtrack:
975 			sg = state.unmapped_sg;
976 			i = state.unmapped_index;
977 
978 			dma_addr = ib_sg_dma_address(ibdev, sg);
979 			dma_len = ib_sg_dma_len(ibdev, sg);
980 			dma_len -= (state.unmapped_addr - dma_addr);
981 			dma_addr = state.unmapped_addr;
982 			use_fmr = SRP_MAP_NO_FMR;
983 			srp_map_desc(&state, dma_addr, dma_len, target->rkey);
984 		}
985 	}
986 
987 	if (use_fmr == SRP_MAP_ALLOW_FMR && srp_map_finish_fmr(&state, target))
988 		goto backtrack;
989 
990 	/* We've mapped the request, now pull as much of the indirect
991 	 * descriptor table as we can into the command buffer. If this
992 	 * target is not using an external indirect table, we are
993 	 * guaranteed to fit into the command, as the SCSI layer won't
994 	 * give us more S/G entries than we allow.
995 	 */
996 	req->nfmr = state.nfmr;
997 	if (state.ndesc == 1) {
998 		/* FMR mapping was able to collapse this to one entry,
999 		 * so use a direct descriptor.
1000 		 */
1001 		struct srp_direct_buf *buf = (void *) cmd->add_data;
1002 
1003 		*buf = req->indirect_desc[0];
1004 		goto map_complete;
1005 	}
1006 
1007 	if (unlikely(target->cmd_sg_cnt < state.ndesc &&
1008 						!target->allow_ext_sg)) {
1009 		shost_printk(KERN_ERR, target->scsi_host,
1010 			     "Could not fit S/G list into SRP_CMD\n");
1011 		return -EIO;
1012 	}
1013 
1014 	count = min(state.ndesc, target->cmd_sg_cnt);
1015 	table_len = state.ndesc * sizeof (struct srp_direct_buf);
1016 
1017 	fmt = SRP_DATA_DESC_INDIRECT;
1018 	len = sizeof(struct srp_cmd) + sizeof (struct srp_indirect_buf);
1019 	len += count * sizeof (struct srp_direct_buf);
1020 
1021 	memcpy(indirect_hdr->desc_list, req->indirect_desc,
1022 	       count * sizeof (struct srp_direct_buf));
1023 
1024 	indirect_hdr->table_desc.va = cpu_to_be64(req->indirect_dma_addr);
1025 	indirect_hdr->table_desc.key = cpu_to_be32(target->rkey);
1026 	indirect_hdr->table_desc.len = cpu_to_be32(table_len);
1027 	indirect_hdr->len = cpu_to_be32(state.total_len);
1028 
1029 	if (scmnd->sc_data_direction == DMA_TO_DEVICE)
1030 		cmd->data_out_desc_cnt = count;
1031 	else
1032 		cmd->data_in_desc_cnt = count;
1033 
1034 	ib_dma_sync_single_for_device(ibdev, req->indirect_dma_addr, table_len,
1035 				      DMA_TO_DEVICE);
1036 
1037 map_complete:
1038 	if (scmnd->sc_data_direction == DMA_TO_DEVICE)
1039 		cmd->buf_fmt = fmt << 4;
1040 	else
1041 		cmd->buf_fmt = fmt;
1042 
1043 	return len;
1044 }
1045 
1046 /*
1047  * Return an IU and possible credit to the free pool
1048  */
1049 static void srp_put_tx_iu(struct srp_target_port *target, struct srp_iu *iu,
1050 			  enum srp_iu_type iu_type)
1051 {
1052 	unsigned long flags;
1053 
1054 	spin_lock_irqsave(&target->lock, flags);
1055 	list_add(&iu->list, &target->free_tx);
1056 	if (iu_type != SRP_IU_RSP)
1057 		++target->req_lim;
1058 	spin_unlock_irqrestore(&target->lock, flags);
1059 }
1060 
1061 /*
1062  * Must be called with target->lock held to protect req_lim and free_tx.
1063  * If IU is not sent, it must be returned using srp_put_tx_iu().
1064  *
1065  * Note:
1066  * An upper limit for the number of allocated information units for each
1067  * request type is:
1068  * - SRP_IU_CMD: SRP_CMD_SQ_SIZE, since the SCSI mid-layer never queues
1069  *   more than Scsi_Host.can_queue requests.
1070  * - SRP_IU_TSK_MGMT: SRP_TSK_MGMT_SQ_SIZE.
1071  * - SRP_IU_RSP: 1, since a conforming SRP target never sends more than
1072  *   one unanswered SRP request to an initiator.
1073  */
1074 static struct srp_iu *__srp_get_tx_iu(struct srp_target_port *target,
1075 				      enum srp_iu_type iu_type)
1076 {
1077 	s32 rsv = (iu_type == SRP_IU_TSK_MGMT) ? 0 : SRP_TSK_MGMT_SQ_SIZE;
1078 	struct srp_iu *iu;
1079 
1080 	srp_send_completion(target->send_cq, target);
1081 
1082 	if (list_empty(&target->free_tx))
1083 		return NULL;
1084 
1085 	/* Initiator responses to target requests do not consume credits */
1086 	if (iu_type != SRP_IU_RSP) {
1087 		if (target->req_lim <= rsv) {
1088 			++target->zero_req_lim;
1089 			return NULL;
1090 		}
1091 
1092 		--target->req_lim;
1093 	}
1094 
1095 	iu = list_first_entry(&target->free_tx, struct srp_iu, list);
1096 	list_del(&iu->list);
1097 	return iu;
1098 }
1099 
1100 static int srp_post_send(struct srp_target_port *target,
1101 			 struct srp_iu *iu, int len)
1102 {
1103 	struct ib_sge list;
1104 	struct ib_send_wr wr, *bad_wr;
1105 
1106 	list.addr   = iu->dma;
1107 	list.length = len;
1108 	list.lkey   = target->lkey;
1109 
1110 	wr.next       = NULL;
1111 	wr.wr_id      = (uintptr_t) iu;
1112 	wr.sg_list    = &list;
1113 	wr.num_sge    = 1;
1114 	wr.opcode     = IB_WR_SEND;
1115 	wr.send_flags = IB_SEND_SIGNALED;
1116 
1117 	return ib_post_send(target->qp, &wr, &bad_wr);
1118 }
1119 
1120 static int srp_post_recv(struct srp_target_port *target, struct srp_iu *iu)
1121 {
1122 	struct ib_recv_wr wr, *bad_wr;
1123 	struct ib_sge list;
1124 
1125 	list.addr   = iu->dma;
1126 	list.length = iu->size;
1127 	list.lkey   = target->lkey;
1128 
1129 	wr.next     = NULL;
1130 	wr.wr_id    = (uintptr_t) iu;
1131 	wr.sg_list  = &list;
1132 	wr.num_sge  = 1;
1133 
1134 	return ib_post_recv(target->qp, &wr, &bad_wr);
1135 }
1136 
1137 static void srp_process_rsp(struct srp_target_port *target, struct srp_rsp *rsp)
1138 {
1139 	struct srp_request *req;
1140 	struct scsi_cmnd *scmnd;
1141 	unsigned long flags;
1142 
1143 	if (unlikely(rsp->tag & SRP_TAG_TSK_MGMT)) {
1144 		spin_lock_irqsave(&target->lock, flags);
1145 		target->req_lim += be32_to_cpu(rsp->req_lim_delta);
1146 		spin_unlock_irqrestore(&target->lock, flags);
1147 
1148 		target->tsk_mgmt_status = -1;
1149 		if (be32_to_cpu(rsp->resp_data_len) >= 4)
1150 			target->tsk_mgmt_status = rsp->data[3];
1151 		complete(&target->tsk_mgmt_done);
1152 	} else {
1153 		req = &target->req_ring[rsp->tag];
1154 		scmnd = srp_claim_req(target, req, NULL);
1155 		if (!scmnd) {
1156 			shost_printk(KERN_ERR, target->scsi_host,
1157 				     "Null scmnd for RSP w/tag %016llx\n",
1158 				     (unsigned long long) rsp->tag);
1159 
1160 			spin_lock_irqsave(&target->lock, flags);
1161 			target->req_lim += be32_to_cpu(rsp->req_lim_delta);
1162 			spin_unlock_irqrestore(&target->lock, flags);
1163 
1164 			return;
1165 		}
1166 		scmnd->result = rsp->status;
1167 
1168 		if (rsp->flags & SRP_RSP_FLAG_SNSVALID) {
1169 			memcpy(scmnd->sense_buffer, rsp->data +
1170 			       be32_to_cpu(rsp->resp_data_len),
1171 			       min_t(int, be32_to_cpu(rsp->sense_data_len),
1172 				     SCSI_SENSE_BUFFERSIZE));
1173 		}
1174 
1175 		if (rsp->flags & (SRP_RSP_FLAG_DOOVER | SRP_RSP_FLAG_DOUNDER))
1176 			scsi_set_resid(scmnd, be32_to_cpu(rsp->data_out_res_cnt));
1177 		else if (rsp->flags & (SRP_RSP_FLAG_DIOVER | SRP_RSP_FLAG_DIUNDER))
1178 			scsi_set_resid(scmnd, be32_to_cpu(rsp->data_in_res_cnt));
1179 
1180 		srp_free_req(target, req, scmnd,
1181 			     be32_to_cpu(rsp->req_lim_delta));
1182 
1183 		scmnd->host_scribble = NULL;
1184 		scmnd->scsi_done(scmnd);
1185 	}
1186 }
1187 
1188 static int srp_response_common(struct srp_target_port *target, s32 req_delta,
1189 			       void *rsp, int len)
1190 {
1191 	struct ib_device *dev = target->srp_host->srp_dev->dev;
1192 	unsigned long flags;
1193 	struct srp_iu *iu;
1194 	int err;
1195 
1196 	spin_lock_irqsave(&target->lock, flags);
1197 	target->req_lim += req_delta;
1198 	iu = __srp_get_tx_iu(target, SRP_IU_RSP);
1199 	spin_unlock_irqrestore(&target->lock, flags);
1200 
1201 	if (!iu) {
1202 		shost_printk(KERN_ERR, target->scsi_host, PFX
1203 			     "no IU available to send response\n");
1204 		return 1;
1205 	}
1206 
1207 	ib_dma_sync_single_for_cpu(dev, iu->dma, len, DMA_TO_DEVICE);
1208 	memcpy(iu->buf, rsp, len);
1209 	ib_dma_sync_single_for_device(dev, iu->dma, len, DMA_TO_DEVICE);
1210 
1211 	err = srp_post_send(target, iu, len);
1212 	if (err) {
1213 		shost_printk(KERN_ERR, target->scsi_host, PFX
1214 			     "unable to post response: %d\n", err);
1215 		srp_put_tx_iu(target, iu, SRP_IU_RSP);
1216 	}
1217 
1218 	return err;
1219 }
1220 
1221 static void srp_process_cred_req(struct srp_target_port *target,
1222 				 struct srp_cred_req *req)
1223 {
1224 	struct srp_cred_rsp rsp = {
1225 		.opcode = SRP_CRED_RSP,
1226 		.tag = req->tag,
1227 	};
1228 	s32 delta = be32_to_cpu(req->req_lim_delta);
1229 
1230 	if (srp_response_common(target, delta, &rsp, sizeof rsp))
1231 		shost_printk(KERN_ERR, target->scsi_host, PFX
1232 			     "problems processing SRP_CRED_REQ\n");
1233 }
1234 
1235 static void srp_process_aer_req(struct srp_target_port *target,
1236 				struct srp_aer_req *req)
1237 {
1238 	struct srp_aer_rsp rsp = {
1239 		.opcode = SRP_AER_RSP,
1240 		.tag = req->tag,
1241 	};
1242 	s32 delta = be32_to_cpu(req->req_lim_delta);
1243 
1244 	shost_printk(KERN_ERR, target->scsi_host, PFX
1245 		     "ignoring AER for LUN %llu\n", be64_to_cpu(req->lun));
1246 
1247 	if (srp_response_common(target, delta, &rsp, sizeof rsp))
1248 		shost_printk(KERN_ERR, target->scsi_host, PFX
1249 			     "problems processing SRP_AER_REQ\n");
1250 }
1251 
1252 static void srp_handle_recv(struct srp_target_port *target, struct ib_wc *wc)
1253 {
1254 	struct ib_device *dev = target->srp_host->srp_dev->dev;
1255 	struct srp_iu *iu = (struct srp_iu *) (uintptr_t) wc->wr_id;
1256 	int res;
1257 	u8 opcode;
1258 
1259 	ib_dma_sync_single_for_cpu(dev, iu->dma, target->max_ti_iu_len,
1260 				   DMA_FROM_DEVICE);
1261 
1262 	opcode = *(u8 *) iu->buf;
1263 
1264 	if (0) {
1265 		shost_printk(KERN_ERR, target->scsi_host,
1266 			     PFX "recv completion, opcode 0x%02x\n", opcode);
1267 		print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 8, 1,
1268 			       iu->buf, wc->byte_len, true);
1269 	}
1270 
1271 	switch (opcode) {
1272 	case SRP_RSP:
1273 		srp_process_rsp(target, iu->buf);
1274 		break;
1275 
1276 	case SRP_CRED_REQ:
1277 		srp_process_cred_req(target, iu->buf);
1278 		break;
1279 
1280 	case SRP_AER_REQ:
1281 		srp_process_aer_req(target, iu->buf);
1282 		break;
1283 
1284 	case SRP_T_LOGOUT:
1285 		/* XXX Handle target logout */
1286 		shost_printk(KERN_WARNING, target->scsi_host,
1287 			     PFX "Got target logout request\n");
1288 		break;
1289 
1290 	default:
1291 		shost_printk(KERN_WARNING, target->scsi_host,
1292 			     PFX "Unhandled SRP opcode 0x%02x\n", opcode);
1293 		break;
1294 	}
1295 
1296 	ib_dma_sync_single_for_device(dev, iu->dma, target->max_ti_iu_len,
1297 				      DMA_FROM_DEVICE);
1298 
1299 	res = srp_post_recv(target, iu);
1300 	if (res != 0)
1301 		shost_printk(KERN_ERR, target->scsi_host,
1302 			     PFX "Recv failed with error code %d\n", res);
1303 }
1304 
1305 static void srp_handle_qp_err(enum ib_wc_status wc_status,
1306 			      enum ib_wc_opcode wc_opcode,
1307 			      struct srp_target_port *target)
1308 {
1309 	if (target->connected && !target->qp_in_error) {
1310 		shost_printk(KERN_ERR, target->scsi_host,
1311 			     PFX "failed %s status %d\n",
1312 			     wc_opcode & IB_WC_RECV ? "receive" : "send",
1313 			     wc_status);
1314 	}
1315 	target->qp_in_error = true;
1316 }
1317 
1318 static void srp_recv_completion(struct ib_cq *cq, void *target_ptr)
1319 {
1320 	struct srp_target_port *target = target_ptr;
1321 	struct ib_wc wc;
1322 
1323 	ib_req_notify_cq(cq, IB_CQ_NEXT_COMP);
1324 	while (ib_poll_cq(cq, 1, &wc) > 0) {
1325 		if (likely(wc.status == IB_WC_SUCCESS)) {
1326 			srp_handle_recv(target, &wc);
1327 		} else {
1328 			srp_handle_qp_err(wc.status, wc.opcode, target);
1329 		}
1330 	}
1331 }
1332 
1333 static void srp_send_completion(struct ib_cq *cq, void *target_ptr)
1334 {
1335 	struct srp_target_port *target = target_ptr;
1336 	struct ib_wc wc;
1337 	struct srp_iu *iu;
1338 
1339 	while (ib_poll_cq(cq, 1, &wc) > 0) {
1340 		if (likely(wc.status == IB_WC_SUCCESS)) {
1341 			iu = (struct srp_iu *) (uintptr_t) wc.wr_id;
1342 			list_add(&iu->list, &target->free_tx);
1343 		} else {
1344 			srp_handle_qp_err(wc.status, wc.opcode, target);
1345 		}
1346 	}
1347 }
1348 
1349 static int srp_queuecommand(struct Scsi_Host *shost, struct scsi_cmnd *scmnd)
1350 {
1351 	struct srp_target_port *target = host_to_target(shost);
1352 	struct srp_request *req;
1353 	struct srp_iu *iu;
1354 	struct srp_cmd *cmd;
1355 	struct ib_device *dev;
1356 	unsigned long flags;
1357 	int len;
1358 
1359 	if (unlikely(target->transport_offline)) {
1360 		scmnd->result = DID_NO_CONNECT << 16;
1361 		scmnd->scsi_done(scmnd);
1362 		return 0;
1363 	}
1364 
1365 	spin_lock_irqsave(&target->lock, flags);
1366 	iu = __srp_get_tx_iu(target, SRP_IU_CMD);
1367 	if (!iu)
1368 		goto err_unlock;
1369 
1370 	req = list_first_entry(&target->free_reqs, struct srp_request, list);
1371 	list_del(&req->list);
1372 	spin_unlock_irqrestore(&target->lock, flags);
1373 
1374 	dev = target->srp_host->srp_dev->dev;
1375 	ib_dma_sync_single_for_cpu(dev, iu->dma, target->max_iu_len,
1376 				   DMA_TO_DEVICE);
1377 
1378 	scmnd->result        = 0;
1379 	scmnd->host_scribble = (void *) req;
1380 
1381 	cmd = iu->buf;
1382 	memset(cmd, 0, sizeof *cmd);
1383 
1384 	cmd->opcode = SRP_CMD;
1385 	cmd->lun    = cpu_to_be64((u64) scmnd->device->lun << 48);
1386 	cmd->tag    = req->index;
1387 	memcpy(cmd->cdb, scmnd->cmnd, scmnd->cmd_len);
1388 
1389 	req->scmnd    = scmnd;
1390 	req->cmd      = iu;
1391 
1392 	len = srp_map_data(scmnd, target, req);
1393 	if (len < 0) {
1394 		shost_printk(KERN_ERR, target->scsi_host,
1395 			     PFX "Failed to map data\n");
1396 		goto err_iu;
1397 	}
1398 
1399 	ib_dma_sync_single_for_device(dev, iu->dma, target->max_iu_len,
1400 				      DMA_TO_DEVICE);
1401 
1402 	if (srp_post_send(target, iu, len)) {
1403 		shost_printk(KERN_ERR, target->scsi_host, PFX "Send failed\n");
1404 		goto err_unmap;
1405 	}
1406 
1407 	return 0;
1408 
1409 err_unmap:
1410 	srp_unmap_data(scmnd, target, req);
1411 
1412 err_iu:
1413 	srp_put_tx_iu(target, iu, SRP_IU_CMD);
1414 
1415 	spin_lock_irqsave(&target->lock, flags);
1416 	list_add(&req->list, &target->free_reqs);
1417 
1418 err_unlock:
1419 	spin_unlock_irqrestore(&target->lock, flags);
1420 
1421 	return SCSI_MLQUEUE_HOST_BUSY;
1422 }
1423 
1424 static int srp_alloc_iu_bufs(struct srp_target_port *target)
1425 {
1426 	int i;
1427 
1428 	for (i = 0; i < SRP_RQ_SIZE; ++i) {
1429 		target->rx_ring[i] = srp_alloc_iu(target->srp_host,
1430 						  target->max_ti_iu_len,
1431 						  GFP_KERNEL, DMA_FROM_DEVICE);
1432 		if (!target->rx_ring[i])
1433 			goto err;
1434 	}
1435 
1436 	for (i = 0; i < SRP_SQ_SIZE; ++i) {
1437 		target->tx_ring[i] = srp_alloc_iu(target->srp_host,
1438 						  target->max_iu_len,
1439 						  GFP_KERNEL, DMA_TO_DEVICE);
1440 		if (!target->tx_ring[i])
1441 			goto err;
1442 
1443 		list_add(&target->tx_ring[i]->list, &target->free_tx);
1444 	}
1445 
1446 	return 0;
1447 
1448 err:
1449 	for (i = 0; i < SRP_RQ_SIZE; ++i) {
1450 		srp_free_iu(target->srp_host, target->rx_ring[i]);
1451 		target->rx_ring[i] = NULL;
1452 	}
1453 
1454 	for (i = 0; i < SRP_SQ_SIZE; ++i) {
1455 		srp_free_iu(target->srp_host, target->tx_ring[i]);
1456 		target->tx_ring[i] = NULL;
1457 	}
1458 
1459 	return -ENOMEM;
1460 }
1461 
1462 static uint32_t srp_compute_rq_tmo(struct ib_qp_attr *qp_attr, int attr_mask)
1463 {
1464 	uint64_t T_tr_ns, max_compl_time_ms;
1465 	uint32_t rq_tmo_jiffies;
1466 
1467 	/*
1468 	 * According to section 11.2.4.2 in the IBTA spec (Modify Queue Pair,
1469 	 * table 91), both the QP timeout and the retry count have to be set
1470 	 * for RC QP's during the RTR to RTS transition.
1471 	 */
1472 	WARN_ON_ONCE((attr_mask & (IB_QP_TIMEOUT | IB_QP_RETRY_CNT)) !=
1473 		     (IB_QP_TIMEOUT | IB_QP_RETRY_CNT));
1474 
1475 	/*
1476 	 * Set target->rq_tmo_jiffies to one second more than the largest time
1477 	 * it can take before an error completion is generated. See also
1478 	 * C9-140..142 in the IBTA spec for more information about how to
1479 	 * convert the QP Local ACK Timeout value to nanoseconds.
1480 	 */
1481 	T_tr_ns = 4096 * (1ULL << qp_attr->timeout);
1482 	max_compl_time_ms = qp_attr->retry_cnt * 4 * T_tr_ns;
1483 	do_div(max_compl_time_ms, NSEC_PER_MSEC);
1484 	rq_tmo_jiffies = msecs_to_jiffies(max_compl_time_ms + 1000);
1485 
1486 	return rq_tmo_jiffies;
1487 }
1488 
1489 static void srp_cm_rep_handler(struct ib_cm_id *cm_id,
1490 			       struct srp_login_rsp *lrsp,
1491 			       struct srp_target_port *target)
1492 {
1493 	struct ib_qp_attr *qp_attr = NULL;
1494 	int attr_mask = 0;
1495 	int ret;
1496 	int i;
1497 
1498 	if (lrsp->opcode == SRP_LOGIN_RSP) {
1499 		target->max_ti_iu_len = be32_to_cpu(lrsp->max_ti_iu_len);
1500 		target->req_lim       = be32_to_cpu(lrsp->req_lim_delta);
1501 
1502 		/*
1503 		 * Reserve credits for task management so we don't
1504 		 * bounce requests back to the SCSI mid-layer.
1505 		 */
1506 		target->scsi_host->can_queue
1507 			= min(target->req_lim - SRP_TSK_MGMT_SQ_SIZE,
1508 			      target->scsi_host->can_queue);
1509 	} else {
1510 		shost_printk(KERN_WARNING, target->scsi_host,
1511 			     PFX "Unhandled RSP opcode %#x\n", lrsp->opcode);
1512 		ret = -ECONNRESET;
1513 		goto error;
1514 	}
1515 
1516 	if (!target->rx_ring[0]) {
1517 		ret = srp_alloc_iu_bufs(target);
1518 		if (ret)
1519 			goto error;
1520 	}
1521 
1522 	ret = -ENOMEM;
1523 	qp_attr = kmalloc(sizeof *qp_attr, GFP_KERNEL);
1524 	if (!qp_attr)
1525 		goto error;
1526 
1527 	qp_attr->qp_state = IB_QPS_RTR;
1528 	ret = ib_cm_init_qp_attr(cm_id, qp_attr, &attr_mask);
1529 	if (ret)
1530 		goto error_free;
1531 
1532 	ret = ib_modify_qp(target->qp, qp_attr, attr_mask);
1533 	if (ret)
1534 		goto error_free;
1535 
1536 	for (i = 0; i < SRP_RQ_SIZE; i++) {
1537 		struct srp_iu *iu = target->rx_ring[i];
1538 		ret = srp_post_recv(target, iu);
1539 		if (ret)
1540 			goto error_free;
1541 	}
1542 
1543 	qp_attr->qp_state = IB_QPS_RTS;
1544 	ret = ib_cm_init_qp_attr(cm_id, qp_attr, &attr_mask);
1545 	if (ret)
1546 		goto error_free;
1547 
1548 	target->rq_tmo_jiffies = srp_compute_rq_tmo(qp_attr, attr_mask);
1549 
1550 	ret = ib_modify_qp(target->qp, qp_attr, attr_mask);
1551 	if (ret)
1552 		goto error_free;
1553 
1554 	ret = ib_send_cm_rtu(cm_id, NULL, 0);
1555 
1556 error_free:
1557 	kfree(qp_attr);
1558 
1559 error:
1560 	target->status = ret;
1561 }
1562 
1563 static void srp_cm_rej_handler(struct ib_cm_id *cm_id,
1564 			       struct ib_cm_event *event,
1565 			       struct srp_target_port *target)
1566 {
1567 	struct Scsi_Host *shost = target->scsi_host;
1568 	struct ib_class_port_info *cpi;
1569 	int opcode;
1570 
1571 	switch (event->param.rej_rcvd.reason) {
1572 	case IB_CM_REJ_PORT_CM_REDIRECT:
1573 		cpi = event->param.rej_rcvd.ari;
1574 		target->path.dlid = cpi->redirect_lid;
1575 		target->path.pkey = cpi->redirect_pkey;
1576 		cm_id->remote_cm_qpn = be32_to_cpu(cpi->redirect_qp) & 0x00ffffff;
1577 		memcpy(target->path.dgid.raw, cpi->redirect_gid, 16);
1578 
1579 		target->status = target->path.dlid ?
1580 			SRP_DLID_REDIRECT : SRP_PORT_REDIRECT;
1581 		break;
1582 
1583 	case IB_CM_REJ_PORT_REDIRECT:
1584 		if (srp_target_is_topspin(target)) {
1585 			/*
1586 			 * Topspin/Cisco SRP gateways incorrectly send
1587 			 * reject reason code 25 when they mean 24
1588 			 * (port redirect).
1589 			 */
1590 			memcpy(target->path.dgid.raw,
1591 			       event->param.rej_rcvd.ari, 16);
1592 
1593 			shost_printk(KERN_DEBUG, shost,
1594 				     PFX "Topspin/Cisco redirect to target port GID %016llx%016llx\n",
1595 				     (unsigned long long) be64_to_cpu(target->path.dgid.global.subnet_prefix),
1596 				     (unsigned long long) be64_to_cpu(target->path.dgid.global.interface_id));
1597 
1598 			target->status = SRP_PORT_REDIRECT;
1599 		} else {
1600 			shost_printk(KERN_WARNING, shost,
1601 				     "  REJ reason: IB_CM_REJ_PORT_REDIRECT\n");
1602 			target->status = -ECONNRESET;
1603 		}
1604 		break;
1605 
1606 	case IB_CM_REJ_DUPLICATE_LOCAL_COMM_ID:
1607 		shost_printk(KERN_WARNING, shost,
1608 			    "  REJ reason: IB_CM_REJ_DUPLICATE_LOCAL_COMM_ID\n");
1609 		target->status = -ECONNRESET;
1610 		break;
1611 
1612 	case IB_CM_REJ_CONSUMER_DEFINED:
1613 		opcode = *(u8 *) event->private_data;
1614 		if (opcode == SRP_LOGIN_REJ) {
1615 			struct srp_login_rej *rej = event->private_data;
1616 			u32 reason = be32_to_cpu(rej->reason);
1617 
1618 			if (reason == SRP_LOGIN_REJ_REQ_IT_IU_LENGTH_TOO_LARGE)
1619 				shost_printk(KERN_WARNING, shost,
1620 					     PFX "SRP_LOGIN_REJ: requested max_it_iu_len too large\n");
1621 			else
1622 				shost_printk(KERN_WARNING, shost,
1623 					    PFX "SRP LOGIN REJECTED, reason 0x%08x\n", reason);
1624 		} else
1625 			shost_printk(KERN_WARNING, shost,
1626 				     "  REJ reason: IB_CM_REJ_CONSUMER_DEFINED,"
1627 				     " opcode 0x%02x\n", opcode);
1628 		target->status = -ECONNRESET;
1629 		break;
1630 
1631 	case IB_CM_REJ_STALE_CONN:
1632 		shost_printk(KERN_WARNING, shost, "  REJ reason: stale connection\n");
1633 		target->status = SRP_STALE_CONN;
1634 		break;
1635 
1636 	default:
1637 		shost_printk(KERN_WARNING, shost, "  REJ reason 0x%x\n",
1638 			     event->param.rej_rcvd.reason);
1639 		target->status = -ECONNRESET;
1640 	}
1641 }
1642 
1643 static int srp_cm_handler(struct ib_cm_id *cm_id, struct ib_cm_event *event)
1644 {
1645 	struct srp_target_port *target = cm_id->context;
1646 	int comp = 0;
1647 
1648 	switch (event->event) {
1649 	case IB_CM_REQ_ERROR:
1650 		shost_printk(KERN_DEBUG, target->scsi_host,
1651 			     PFX "Sending CM REQ failed\n");
1652 		comp = 1;
1653 		target->status = -ECONNRESET;
1654 		break;
1655 
1656 	case IB_CM_REP_RECEIVED:
1657 		comp = 1;
1658 		srp_cm_rep_handler(cm_id, event->private_data, target);
1659 		break;
1660 
1661 	case IB_CM_REJ_RECEIVED:
1662 		shost_printk(KERN_DEBUG, target->scsi_host, PFX "REJ received\n");
1663 		comp = 1;
1664 
1665 		srp_cm_rej_handler(cm_id, event, target);
1666 		break;
1667 
1668 	case IB_CM_DREQ_RECEIVED:
1669 		shost_printk(KERN_WARNING, target->scsi_host,
1670 			     PFX "DREQ received - connection closed\n");
1671 		srp_change_conn_state(target, false);
1672 		if (ib_send_cm_drep(cm_id, NULL, 0))
1673 			shost_printk(KERN_ERR, target->scsi_host,
1674 				     PFX "Sending CM DREP failed\n");
1675 		break;
1676 
1677 	case IB_CM_TIMEWAIT_EXIT:
1678 		shost_printk(KERN_ERR, target->scsi_host,
1679 			     PFX "connection closed\n");
1680 
1681 		target->status = 0;
1682 		break;
1683 
1684 	case IB_CM_MRA_RECEIVED:
1685 	case IB_CM_DREQ_ERROR:
1686 	case IB_CM_DREP_RECEIVED:
1687 		break;
1688 
1689 	default:
1690 		shost_printk(KERN_WARNING, target->scsi_host,
1691 			     PFX "Unhandled CM event %d\n", event->event);
1692 		break;
1693 	}
1694 
1695 	if (comp)
1696 		complete(&target->done);
1697 
1698 	return 0;
1699 }
1700 
1701 static int srp_send_tsk_mgmt(struct srp_target_port *target,
1702 			     u64 req_tag, unsigned int lun, u8 func)
1703 {
1704 	struct ib_device *dev = target->srp_host->srp_dev->dev;
1705 	struct srp_iu *iu;
1706 	struct srp_tsk_mgmt *tsk_mgmt;
1707 
1708 	if (!target->connected || target->qp_in_error)
1709 		return -1;
1710 
1711 	init_completion(&target->tsk_mgmt_done);
1712 
1713 	spin_lock_irq(&target->lock);
1714 	iu = __srp_get_tx_iu(target, SRP_IU_TSK_MGMT);
1715 	spin_unlock_irq(&target->lock);
1716 
1717 	if (!iu)
1718 		return -1;
1719 
1720 	ib_dma_sync_single_for_cpu(dev, iu->dma, sizeof *tsk_mgmt,
1721 				   DMA_TO_DEVICE);
1722 	tsk_mgmt = iu->buf;
1723 	memset(tsk_mgmt, 0, sizeof *tsk_mgmt);
1724 
1725 	tsk_mgmt->opcode 	= SRP_TSK_MGMT;
1726 	tsk_mgmt->lun		= cpu_to_be64((u64) lun << 48);
1727 	tsk_mgmt->tag		= req_tag | SRP_TAG_TSK_MGMT;
1728 	tsk_mgmt->tsk_mgmt_func = func;
1729 	tsk_mgmt->task_tag	= req_tag;
1730 
1731 	ib_dma_sync_single_for_device(dev, iu->dma, sizeof *tsk_mgmt,
1732 				      DMA_TO_DEVICE);
1733 	if (srp_post_send(target, iu, sizeof *tsk_mgmt)) {
1734 		srp_put_tx_iu(target, iu, SRP_IU_TSK_MGMT);
1735 		return -1;
1736 	}
1737 
1738 	if (!wait_for_completion_timeout(&target->tsk_mgmt_done,
1739 					 msecs_to_jiffies(SRP_ABORT_TIMEOUT_MS)))
1740 		return -1;
1741 
1742 	return 0;
1743 }
1744 
1745 static int srp_abort(struct scsi_cmnd *scmnd)
1746 {
1747 	struct srp_target_port *target = host_to_target(scmnd->device->host);
1748 	struct srp_request *req = (struct srp_request *) scmnd->host_scribble;
1749 	int ret;
1750 
1751 	shost_printk(KERN_ERR, target->scsi_host, "SRP abort called\n");
1752 
1753 	if (!req || !srp_claim_req(target, req, scmnd))
1754 		return FAILED;
1755 	if (srp_send_tsk_mgmt(target, req->index, scmnd->device->lun,
1756 			      SRP_TSK_ABORT_TASK) == 0)
1757 		ret = SUCCESS;
1758 	else if (target->transport_offline)
1759 		ret = FAST_IO_FAIL;
1760 	else
1761 		ret = FAILED;
1762 	srp_free_req(target, req, scmnd, 0);
1763 	scmnd->result = DID_ABORT << 16;
1764 	scmnd->scsi_done(scmnd);
1765 
1766 	return ret;
1767 }
1768 
1769 static int srp_reset_device(struct scsi_cmnd *scmnd)
1770 {
1771 	struct srp_target_port *target = host_to_target(scmnd->device->host);
1772 	int i;
1773 
1774 	shost_printk(KERN_ERR, target->scsi_host, "SRP reset_device called\n");
1775 
1776 	if (srp_send_tsk_mgmt(target, SRP_TAG_NO_REQ, scmnd->device->lun,
1777 			      SRP_TSK_LUN_RESET))
1778 		return FAILED;
1779 	if (target->tsk_mgmt_status)
1780 		return FAILED;
1781 
1782 	for (i = 0; i < SRP_CMD_SQ_SIZE; ++i) {
1783 		struct srp_request *req = &target->req_ring[i];
1784 		if (req->scmnd && req->scmnd->device == scmnd->device)
1785 			srp_reset_req(target, req);
1786 	}
1787 
1788 	return SUCCESS;
1789 }
1790 
1791 static int srp_reset_host(struct scsi_cmnd *scmnd)
1792 {
1793 	struct srp_target_port *target = host_to_target(scmnd->device->host);
1794 	int ret = FAILED;
1795 
1796 	shost_printk(KERN_ERR, target->scsi_host, PFX "SRP reset_host called\n");
1797 
1798 	if (!srp_reconnect_target(target))
1799 		ret = SUCCESS;
1800 
1801 	return ret;
1802 }
1803 
1804 static int srp_slave_configure(struct scsi_device *sdev)
1805 {
1806 	struct Scsi_Host *shost = sdev->host;
1807 	struct srp_target_port *target = host_to_target(shost);
1808 	struct request_queue *q = sdev->request_queue;
1809 	unsigned long timeout;
1810 
1811 	if (sdev->type == TYPE_DISK) {
1812 		timeout = max_t(unsigned, 30 * HZ, target->rq_tmo_jiffies);
1813 		blk_queue_rq_timeout(q, timeout);
1814 	}
1815 
1816 	return 0;
1817 }
1818 
1819 static ssize_t show_id_ext(struct device *dev, struct device_attribute *attr,
1820 			   char *buf)
1821 {
1822 	struct srp_target_port *target = host_to_target(class_to_shost(dev));
1823 
1824 	return sprintf(buf, "0x%016llx\n",
1825 		       (unsigned long long) be64_to_cpu(target->id_ext));
1826 }
1827 
1828 static ssize_t show_ioc_guid(struct device *dev, struct device_attribute *attr,
1829 			     char *buf)
1830 {
1831 	struct srp_target_port *target = host_to_target(class_to_shost(dev));
1832 
1833 	return sprintf(buf, "0x%016llx\n",
1834 		       (unsigned long long) be64_to_cpu(target->ioc_guid));
1835 }
1836 
1837 static ssize_t show_service_id(struct device *dev,
1838 			       struct device_attribute *attr, char *buf)
1839 {
1840 	struct srp_target_port *target = host_to_target(class_to_shost(dev));
1841 
1842 	return sprintf(buf, "0x%016llx\n",
1843 		       (unsigned long long) be64_to_cpu(target->service_id));
1844 }
1845 
1846 static ssize_t show_pkey(struct device *dev, struct device_attribute *attr,
1847 			 char *buf)
1848 {
1849 	struct srp_target_port *target = host_to_target(class_to_shost(dev));
1850 
1851 	return sprintf(buf, "0x%04x\n", be16_to_cpu(target->path.pkey));
1852 }
1853 
1854 static ssize_t show_dgid(struct device *dev, struct device_attribute *attr,
1855 			 char *buf)
1856 {
1857 	struct srp_target_port *target = host_to_target(class_to_shost(dev));
1858 
1859 	return sprintf(buf, "%pI6\n", target->path.dgid.raw);
1860 }
1861 
1862 static ssize_t show_orig_dgid(struct device *dev,
1863 			      struct device_attribute *attr, char *buf)
1864 {
1865 	struct srp_target_port *target = host_to_target(class_to_shost(dev));
1866 
1867 	return sprintf(buf, "%pI6\n", target->orig_dgid);
1868 }
1869 
1870 static ssize_t show_req_lim(struct device *dev,
1871 			    struct device_attribute *attr, char *buf)
1872 {
1873 	struct srp_target_port *target = host_to_target(class_to_shost(dev));
1874 
1875 	return sprintf(buf, "%d\n", target->req_lim);
1876 }
1877 
1878 static ssize_t show_zero_req_lim(struct device *dev,
1879 				 struct device_attribute *attr, char *buf)
1880 {
1881 	struct srp_target_port *target = host_to_target(class_to_shost(dev));
1882 
1883 	return sprintf(buf, "%d\n", target->zero_req_lim);
1884 }
1885 
1886 static ssize_t show_local_ib_port(struct device *dev,
1887 				  struct device_attribute *attr, char *buf)
1888 {
1889 	struct srp_target_port *target = host_to_target(class_to_shost(dev));
1890 
1891 	return sprintf(buf, "%d\n", target->srp_host->port);
1892 }
1893 
1894 static ssize_t show_local_ib_device(struct device *dev,
1895 				    struct device_attribute *attr, char *buf)
1896 {
1897 	struct srp_target_port *target = host_to_target(class_to_shost(dev));
1898 
1899 	return sprintf(buf, "%s\n", target->srp_host->srp_dev->dev->name);
1900 }
1901 
1902 static ssize_t show_comp_vector(struct device *dev,
1903 				struct device_attribute *attr, char *buf)
1904 {
1905 	struct srp_target_port *target = host_to_target(class_to_shost(dev));
1906 
1907 	return sprintf(buf, "%d\n", target->comp_vector);
1908 }
1909 
1910 static ssize_t show_cmd_sg_entries(struct device *dev,
1911 				   struct device_attribute *attr, char *buf)
1912 {
1913 	struct srp_target_port *target = host_to_target(class_to_shost(dev));
1914 
1915 	return sprintf(buf, "%u\n", target->cmd_sg_cnt);
1916 }
1917 
1918 static ssize_t show_allow_ext_sg(struct device *dev,
1919 				 struct device_attribute *attr, char *buf)
1920 {
1921 	struct srp_target_port *target = host_to_target(class_to_shost(dev));
1922 
1923 	return sprintf(buf, "%s\n", target->allow_ext_sg ? "true" : "false");
1924 }
1925 
1926 static DEVICE_ATTR(id_ext,	    S_IRUGO, show_id_ext,	   NULL);
1927 static DEVICE_ATTR(ioc_guid,	    S_IRUGO, show_ioc_guid,	   NULL);
1928 static DEVICE_ATTR(service_id,	    S_IRUGO, show_service_id,	   NULL);
1929 static DEVICE_ATTR(pkey,	    S_IRUGO, show_pkey,		   NULL);
1930 static DEVICE_ATTR(dgid,	    S_IRUGO, show_dgid,		   NULL);
1931 static DEVICE_ATTR(orig_dgid,	    S_IRUGO, show_orig_dgid,	   NULL);
1932 static DEVICE_ATTR(req_lim,         S_IRUGO, show_req_lim,         NULL);
1933 static DEVICE_ATTR(zero_req_lim,    S_IRUGO, show_zero_req_lim,	   NULL);
1934 static DEVICE_ATTR(local_ib_port,   S_IRUGO, show_local_ib_port,   NULL);
1935 static DEVICE_ATTR(local_ib_device, S_IRUGO, show_local_ib_device, NULL);
1936 static DEVICE_ATTR(comp_vector,     S_IRUGO, show_comp_vector,     NULL);
1937 static DEVICE_ATTR(cmd_sg_entries,  S_IRUGO, show_cmd_sg_entries,  NULL);
1938 static DEVICE_ATTR(allow_ext_sg,    S_IRUGO, show_allow_ext_sg,    NULL);
1939 
1940 static struct device_attribute *srp_host_attrs[] = {
1941 	&dev_attr_id_ext,
1942 	&dev_attr_ioc_guid,
1943 	&dev_attr_service_id,
1944 	&dev_attr_pkey,
1945 	&dev_attr_dgid,
1946 	&dev_attr_orig_dgid,
1947 	&dev_attr_req_lim,
1948 	&dev_attr_zero_req_lim,
1949 	&dev_attr_local_ib_port,
1950 	&dev_attr_local_ib_device,
1951 	&dev_attr_comp_vector,
1952 	&dev_attr_cmd_sg_entries,
1953 	&dev_attr_allow_ext_sg,
1954 	NULL
1955 };
1956 
1957 static struct scsi_host_template srp_template = {
1958 	.module				= THIS_MODULE,
1959 	.name				= "InfiniBand SRP initiator",
1960 	.proc_name			= DRV_NAME,
1961 	.slave_configure		= srp_slave_configure,
1962 	.info				= srp_target_info,
1963 	.queuecommand			= srp_queuecommand,
1964 	.eh_abort_handler		= srp_abort,
1965 	.eh_device_reset_handler	= srp_reset_device,
1966 	.eh_host_reset_handler		= srp_reset_host,
1967 	.skip_settle_delay		= true,
1968 	.sg_tablesize			= SRP_DEF_SG_TABLESIZE,
1969 	.can_queue			= SRP_CMD_SQ_SIZE,
1970 	.this_id			= -1,
1971 	.cmd_per_lun			= SRP_CMD_SQ_SIZE,
1972 	.use_clustering			= ENABLE_CLUSTERING,
1973 	.shost_attrs			= srp_host_attrs
1974 };
1975 
1976 static int srp_add_target(struct srp_host *host, struct srp_target_port *target)
1977 {
1978 	struct srp_rport_identifiers ids;
1979 	struct srp_rport *rport;
1980 
1981 	sprintf(target->target_name, "SRP.T10:%016llX",
1982 		 (unsigned long long) be64_to_cpu(target->id_ext));
1983 
1984 	if (scsi_add_host(target->scsi_host, host->srp_dev->dev->dma_device))
1985 		return -ENODEV;
1986 
1987 	memcpy(ids.port_id, &target->id_ext, 8);
1988 	memcpy(ids.port_id + 8, &target->ioc_guid, 8);
1989 	ids.roles = SRP_RPORT_ROLE_TARGET;
1990 	rport = srp_rport_add(target->scsi_host, &ids);
1991 	if (IS_ERR(rport)) {
1992 		scsi_remove_host(target->scsi_host);
1993 		return PTR_ERR(rport);
1994 	}
1995 
1996 	rport->lld_data = target;
1997 
1998 	spin_lock(&host->target_lock);
1999 	list_add_tail(&target->list, &host->target_list);
2000 	spin_unlock(&host->target_lock);
2001 
2002 	target->state = SRP_TARGET_LIVE;
2003 
2004 	scsi_scan_target(&target->scsi_host->shost_gendev,
2005 			 0, target->scsi_id, SCAN_WILD_CARD, 0);
2006 
2007 	return 0;
2008 }
2009 
2010 static void srp_release_dev(struct device *dev)
2011 {
2012 	struct srp_host *host =
2013 		container_of(dev, struct srp_host, dev);
2014 
2015 	complete(&host->released);
2016 }
2017 
2018 static struct class srp_class = {
2019 	.name    = "infiniband_srp",
2020 	.dev_release = srp_release_dev
2021 };
2022 
2023 /**
2024  * srp_conn_unique() - check whether the connection to a target is unique
2025  */
2026 static bool srp_conn_unique(struct srp_host *host,
2027 			    struct srp_target_port *target)
2028 {
2029 	struct srp_target_port *t;
2030 	bool ret = false;
2031 
2032 	if (target->state == SRP_TARGET_REMOVED)
2033 		goto out;
2034 
2035 	ret = true;
2036 
2037 	spin_lock(&host->target_lock);
2038 	list_for_each_entry(t, &host->target_list, list) {
2039 		if (t != target &&
2040 		    target->id_ext == t->id_ext &&
2041 		    target->ioc_guid == t->ioc_guid &&
2042 		    target->initiator_ext == t->initiator_ext) {
2043 			ret = false;
2044 			break;
2045 		}
2046 	}
2047 	spin_unlock(&host->target_lock);
2048 
2049 out:
2050 	return ret;
2051 }
2052 
2053 /*
2054  * Target ports are added by writing
2055  *
2056  *     id_ext=<SRP ID ext>,ioc_guid=<SRP IOC GUID>,dgid=<dest GID>,
2057  *     pkey=<P_Key>,service_id=<service ID>
2058  *
2059  * to the add_target sysfs attribute.
2060  */
2061 enum {
2062 	SRP_OPT_ERR		= 0,
2063 	SRP_OPT_ID_EXT		= 1 << 0,
2064 	SRP_OPT_IOC_GUID	= 1 << 1,
2065 	SRP_OPT_DGID		= 1 << 2,
2066 	SRP_OPT_PKEY		= 1 << 3,
2067 	SRP_OPT_SERVICE_ID	= 1 << 4,
2068 	SRP_OPT_MAX_SECT	= 1 << 5,
2069 	SRP_OPT_MAX_CMD_PER_LUN	= 1 << 6,
2070 	SRP_OPT_IO_CLASS	= 1 << 7,
2071 	SRP_OPT_INITIATOR_EXT	= 1 << 8,
2072 	SRP_OPT_CMD_SG_ENTRIES	= 1 << 9,
2073 	SRP_OPT_ALLOW_EXT_SG	= 1 << 10,
2074 	SRP_OPT_SG_TABLESIZE	= 1 << 11,
2075 	SRP_OPT_COMP_VECTOR	= 1 << 12,
2076 	SRP_OPT_ALL		= (SRP_OPT_ID_EXT	|
2077 				   SRP_OPT_IOC_GUID	|
2078 				   SRP_OPT_DGID		|
2079 				   SRP_OPT_PKEY		|
2080 				   SRP_OPT_SERVICE_ID),
2081 };
2082 
2083 static const match_table_t srp_opt_tokens = {
2084 	{ SRP_OPT_ID_EXT,		"id_ext=%s" 		},
2085 	{ SRP_OPT_IOC_GUID,		"ioc_guid=%s" 		},
2086 	{ SRP_OPT_DGID,			"dgid=%s" 		},
2087 	{ SRP_OPT_PKEY,			"pkey=%x" 		},
2088 	{ SRP_OPT_SERVICE_ID,		"service_id=%s"		},
2089 	{ SRP_OPT_MAX_SECT,		"max_sect=%d" 		},
2090 	{ SRP_OPT_MAX_CMD_PER_LUN,	"max_cmd_per_lun=%d" 	},
2091 	{ SRP_OPT_IO_CLASS,		"io_class=%x"		},
2092 	{ SRP_OPT_INITIATOR_EXT,	"initiator_ext=%s"	},
2093 	{ SRP_OPT_CMD_SG_ENTRIES,	"cmd_sg_entries=%u"	},
2094 	{ SRP_OPT_ALLOW_EXT_SG,		"allow_ext_sg=%u"	},
2095 	{ SRP_OPT_SG_TABLESIZE,		"sg_tablesize=%u"	},
2096 	{ SRP_OPT_COMP_VECTOR,		"comp_vector=%u"	},
2097 	{ SRP_OPT_ERR,			NULL 			}
2098 };
2099 
2100 static int srp_parse_options(const char *buf, struct srp_target_port *target)
2101 {
2102 	char *options, *sep_opt;
2103 	char *p;
2104 	char dgid[3];
2105 	substring_t args[MAX_OPT_ARGS];
2106 	int opt_mask = 0;
2107 	int token;
2108 	int ret = -EINVAL;
2109 	int i;
2110 
2111 	options = kstrdup(buf, GFP_KERNEL);
2112 	if (!options)
2113 		return -ENOMEM;
2114 
2115 	sep_opt = options;
2116 	while ((p = strsep(&sep_opt, ",")) != NULL) {
2117 		if (!*p)
2118 			continue;
2119 
2120 		token = match_token(p, srp_opt_tokens, args);
2121 		opt_mask |= token;
2122 
2123 		switch (token) {
2124 		case SRP_OPT_ID_EXT:
2125 			p = match_strdup(args);
2126 			if (!p) {
2127 				ret = -ENOMEM;
2128 				goto out;
2129 			}
2130 			target->id_ext = cpu_to_be64(simple_strtoull(p, NULL, 16));
2131 			kfree(p);
2132 			break;
2133 
2134 		case SRP_OPT_IOC_GUID:
2135 			p = match_strdup(args);
2136 			if (!p) {
2137 				ret = -ENOMEM;
2138 				goto out;
2139 			}
2140 			target->ioc_guid = cpu_to_be64(simple_strtoull(p, NULL, 16));
2141 			kfree(p);
2142 			break;
2143 
2144 		case SRP_OPT_DGID:
2145 			p = match_strdup(args);
2146 			if (!p) {
2147 				ret = -ENOMEM;
2148 				goto out;
2149 			}
2150 			if (strlen(p) != 32) {
2151 				pr_warn("bad dest GID parameter '%s'\n", p);
2152 				kfree(p);
2153 				goto out;
2154 			}
2155 
2156 			for (i = 0; i < 16; ++i) {
2157 				strlcpy(dgid, p + i * 2, 3);
2158 				target->path.dgid.raw[i] = simple_strtoul(dgid, NULL, 16);
2159 			}
2160 			kfree(p);
2161 			memcpy(target->orig_dgid, target->path.dgid.raw, 16);
2162 			break;
2163 
2164 		case SRP_OPT_PKEY:
2165 			if (match_hex(args, &token)) {
2166 				pr_warn("bad P_Key parameter '%s'\n", p);
2167 				goto out;
2168 			}
2169 			target->path.pkey = cpu_to_be16(token);
2170 			break;
2171 
2172 		case SRP_OPT_SERVICE_ID:
2173 			p = match_strdup(args);
2174 			if (!p) {
2175 				ret = -ENOMEM;
2176 				goto out;
2177 			}
2178 			target->service_id = cpu_to_be64(simple_strtoull(p, NULL, 16));
2179 			target->path.service_id = target->service_id;
2180 			kfree(p);
2181 			break;
2182 
2183 		case SRP_OPT_MAX_SECT:
2184 			if (match_int(args, &token)) {
2185 				pr_warn("bad max sect parameter '%s'\n", p);
2186 				goto out;
2187 			}
2188 			target->scsi_host->max_sectors = token;
2189 			break;
2190 
2191 		case SRP_OPT_MAX_CMD_PER_LUN:
2192 			if (match_int(args, &token)) {
2193 				pr_warn("bad max cmd_per_lun parameter '%s'\n",
2194 					p);
2195 				goto out;
2196 			}
2197 			target->scsi_host->cmd_per_lun = min(token, SRP_CMD_SQ_SIZE);
2198 			break;
2199 
2200 		case SRP_OPT_IO_CLASS:
2201 			if (match_hex(args, &token)) {
2202 				pr_warn("bad IO class parameter '%s'\n", p);
2203 				goto out;
2204 			}
2205 			if (token != SRP_REV10_IB_IO_CLASS &&
2206 			    token != SRP_REV16A_IB_IO_CLASS) {
2207 				pr_warn("unknown IO class parameter value %x specified (use %x or %x).\n",
2208 					token, SRP_REV10_IB_IO_CLASS,
2209 					SRP_REV16A_IB_IO_CLASS);
2210 				goto out;
2211 			}
2212 			target->io_class = token;
2213 			break;
2214 
2215 		case SRP_OPT_INITIATOR_EXT:
2216 			p = match_strdup(args);
2217 			if (!p) {
2218 				ret = -ENOMEM;
2219 				goto out;
2220 			}
2221 			target->initiator_ext = cpu_to_be64(simple_strtoull(p, NULL, 16));
2222 			kfree(p);
2223 			break;
2224 
2225 		case SRP_OPT_CMD_SG_ENTRIES:
2226 			if (match_int(args, &token) || token < 1 || token > 255) {
2227 				pr_warn("bad max cmd_sg_entries parameter '%s'\n",
2228 					p);
2229 				goto out;
2230 			}
2231 			target->cmd_sg_cnt = token;
2232 			break;
2233 
2234 		case SRP_OPT_ALLOW_EXT_SG:
2235 			if (match_int(args, &token)) {
2236 				pr_warn("bad allow_ext_sg parameter '%s'\n", p);
2237 				goto out;
2238 			}
2239 			target->allow_ext_sg = !!token;
2240 			break;
2241 
2242 		case SRP_OPT_SG_TABLESIZE:
2243 			if (match_int(args, &token) || token < 1 ||
2244 					token > SCSI_MAX_SG_CHAIN_SEGMENTS) {
2245 				pr_warn("bad max sg_tablesize parameter '%s'\n",
2246 					p);
2247 				goto out;
2248 			}
2249 			target->sg_tablesize = token;
2250 			break;
2251 
2252 		case SRP_OPT_COMP_VECTOR:
2253 			if (match_int(args, &token) || token < 0) {
2254 				pr_warn("bad comp_vector parameter '%s'\n", p);
2255 				goto out;
2256 			}
2257 			target->comp_vector = token;
2258 			break;
2259 
2260 		default:
2261 			pr_warn("unknown parameter or missing value '%s' in target creation request\n",
2262 				p);
2263 			goto out;
2264 		}
2265 	}
2266 
2267 	if ((opt_mask & SRP_OPT_ALL) == SRP_OPT_ALL)
2268 		ret = 0;
2269 	else
2270 		for (i = 0; i < ARRAY_SIZE(srp_opt_tokens); ++i)
2271 			if ((srp_opt_tokens[i].token & SRP_OPT_ALL) &&
2272 			    !(srp_opt_tokens[i].token & opt_mask))
2273 				pr_warn("target creation request is missing parameter '%s'\n",
2274 					srp_opt_tokens[i].pattern);
2275 
2276 out:
2277 	kfree(options);
2278 	return ret;
2279 }
2280 
2281 static ssize_t srp_create_target(struct device *dev,
2282 				 struct device_attribute *attr,
2283 				 const char *buf, size_t count)
2284 {
2285 	struct srp_host *host =
2286 		container_of(dev, struct srp_host, dev);
2287 	struct Scsi_Host *target_host;
2288 	struct srp_target_port *target;
2289 	struct ib_device *ibdev = host->srp_dev->dev;
2290 	dma_addr_t dma_addr;
2291 	int i, ret;
2292 
2293 	target_host = scsi_host_alloc(&srp_template,
2294 				      sizeof (struct srp_target_port));
2295 	if (!target_host)
2296 		return -ENOMEM;
2297 
2298 	target_host->transportt  = ib_srp_transport_template;
2299 	target_host->max_channel = 0;
2300 	target_host->max_id      = 1;
2301 	target_host->max_lun     = SRP_MAX_LUN;
2302 	target_host->max_cmd_len = sizeof ((struct srp_cmd *) (void *) 0L)->cdb;
2303 
2304 	target = host_to_target(target_host);
2305 
2306 	target->io_class	= SRP_REV16A_IB_IO_CLASS;
2307 	target->scsi_host	= target_host;
2308 	target->srp_host	= host;
2309 	target->lkey		= host->srp_dev->mr->lkey;
2310 	target->rkey		= host->srp_dev->mr->rkey;
2311 	target->cmd_sg_cnt	= cmd_sg_entries;
2312 	target->sg_tablesize	= indirect_sg_entries ? : cmd_sg_entries;
2313 	target->allow_ext_sg	= allow_ext_sg;
2314 
2315 	ret = srp_parse_options(buf, target);
2316 	if (ret)
2317 		goto err;
2318 
2319 	if (!srp_conn_unique(target->srp_host, target)) {
2320 		shost_printk(KERN_INFO, target->scsi_host,
2321 			     PFX "Already connected to target port with id_ext=%016llx;ioc_guid=%016llx;initiator_ext=%016llx\n",
2322 			     be64_to_cpu(target->id_ext),
2323 			     be64_to_cpu(target->ioc_guid),
2324 			     be64_to_cpu(target->initiator_ext));
2325 		ret = -EEXIST;
2326 		goto err;
2327 	}
2328 
2329 	if (!host->srp_dev->fmr_pool && !target->allow_ext_sg &&
2330 				target->cmd_sg_cnt < target->sg_tablesize) {
2331 		pr_warn("No FMR pool and no external indirect descriptors, limiting sg_tablesize to cmd_sg_cnt\n");
2332 		target->sg_tablesize = target->cmd_sg_cnt;
2333 	}
2334 
2335 	target_host->sg_tablesize = target->sg_tablesize;
2336 	target->indirect_size = target->sg_tablesize *
2337 				sizeof (struct srp_direct_buf);
2338 	target->max_iu_len = sizeof (struct srp_cmd) +
2339 			     sizeof (struct srp_indirect_buf) +
2340 			     target->cmd_sg_cnt * sizeof (struct srp_direct_buf);
2341 
2342 	INIT_WORK(&target->remove_work, srp_remove_work);
2343 	spin_lock_init(&target->lock);
2344 	INIT_LIST_HEAD(&target->free_tx);
2345 	INIT_LIST_HEAD(&target->free_reqs);
2346 	for (i = 0; i < SRP_CMD_SQ_SIZE; ++i) {
2347 		struct srp_request *req = &target->req_ring[i];
2348 
2349 		req->fmr_list = kmalloc(target->cmd_sg_cnt * sizeof (void *),
2350 					GFP_KERNEL);
2351 		req->map_page = kmalloc(SRP_FMR_SIZE * sizeof (void *),
2352 					GFP_KERNEL);
2353 		req->indirect_desc = kmalloc(target->indirect_size, GFP_KERNEL);
2354 		if (!req->fmr_list || !req->map_page || !req->indirect_desc)
2355 			goto err_free_mem;
2356 
2357 		dma_addr = ib_dma_map_single(ibdev, req->indirect_desc,
2358 					     target->indirect_size,
2359 					     DMA_TO_DEVICE);
2360 		if (ib_dma_mapping_error(ibdev, dma_addr))
2361 			goto err_free_mem;
2362 
2363 		req->indirect_dma_addr = dma_addr;
2364 		req->index = i;
2365 		list_add_tail(&req->list, &target->free_reqs);
2366 	}
2367 
2368 	ib_query_gid(ibdev, host->port, 0, &target->path.sgid);
2369 
2370 	shost_printk(KERN_DEBUG, target->scsi_host, PFX
2371 		     "new target: id_ext %016llx ioc_guid %016llx pkey %04x "
2372 		     "service_id %016llx dgid %pI6\n",
2373 	       (unsigned long long) be64_to_cpu(target->id_ext),
2374 	       (unsigned long long) be64_to_cpu(target->ioc_guid),
2375 	       be16_to_cpu(target->path.pkey),
2376 	       (unsigned long long) be64_to_cpu(target->service_id),
2377 	       target->path.dgid.raw);
2378 
2379 	ret = srp_create_target_ib(target);
2380 	if (ret)
2381 		goto err_free_mem;
2382 
2383 	ret = srp_new_cm_id(target);
2384 	if (ret)
2385 		goto err_free_ib;
2386 
2387 	ret = srp_connect_target(target);
2388 	if (ret) {
2389 		shost_printk(KERN_ERR, target->scsi_host,
2390 			     PFX "Connection failed\n");
2391 		goto err_cm_id;
2392 	}
2393 
2394 	ret = srp_add_target(host, target);
2395 	if (ret)
2396 		goto err_disconnect;
2397 
2398 	return count;
2399 
2400 err_disconnect:
2401 	srp_disconnect_target(target);
2402 
2403 err_cm_id:
2404 	ib_destroy_cm_id(target->cm_id);
2405 
2406 err_free_ib:
2407 	srp_free_target_ib(target);
2408 
2409 err_free_mem:
2410 	srp_free_req_data(target);
2411 
2412 err:
2413 	scsi_host_put(target_host);
2414 
2415 	return ret;
2416 }
2417 
2418 static DEVICE_ATTR(add_target, S_IWUSR, NULL, srp_create_target);
2419 
2420 static ssize_t show_ibdev(struct device *dev, struct device_attribute *attr,
2421 			  char *buf)
2422 {
2423 	struct srp_host *host = container_of(dev, struct srp_host, dev);
2424 
2425 	return sprintf(buf, "%s\n", host->srp_dev->dev->name);
2426 }
2427 
2428 static DEVICE_ATTR(ibdev, S_IRUGO, show_ibdev, NULL);
2429 
2430 static ssize_t show_port(struct device *dev, struct device_attribute *attr,
2431 			 char *buf)
2432 {
2433 	struct srp_host *host = container_of(dev, struct srp_host, dev);
2434 
2435 	return sprintf(buf, "%d\n", host->port);
2436 }
2437 
2438 static DEVICE_ATTR(port, S_IRUGO, show_port, NULL);
2439 
2440 static struct srp_host *srp_add_port(struct srp_device *device, u8 port)
2441 {
2442 	struct srp_host *host;
2443 
2444 	host = kzalloc(sizeof *host, GFP_KERNEL);
2445 	if (!host)
2446 		return NULL;
2447 
2448 	INIT_LIST_HEAD(&host->target_list);
2449 	spin_lock_init(&host->target_lock);
2450 	init_completion(&host->released);
2451 	host->srp_dev = device;
2452 	host->port = port;
2453 
2454 	host->dev.class = &srp_class;
2455 	host->dev.parent = device->dev->dma_device;
2456 	dev_set_name(&host->dev, "srp-%s-%d", device->dev->name, port);
2457 
2458 	if (device_register(&host->dev))
2459 		goto free_host;
2460 	if (device_create_file(&host->dev, &dev_attr_add_target))
2461 		goto err_class;
2462 	if (device_create_file(&host->dev, &dev_attr_ibdev))
2463 		goto err_class;
2464 	if (device_create_file(&host->dev, &dev_attr_port))
2465 		goto err_class;
2466 
2467 	return host;
2468 
2469 err_class:
2470 	device_unregister(&host->dev);
2471 
2472 free_host:
2473 	kfree(host);
2474 
2475 	return NULL;
2476 }
2477 
2478 static void srp_add_one(struct ib_device *device)
2479 {
2480 	struct srp_device *srp_dev;
2481 	struct ib_device_attr *dev_attr;
2482 	struct ib_fmr_pool_param fmr_param;
2483 	struct srp_host *host;
2484 	int max_pages_per_fmr, fmr_page_shift, s, e, p;
2485 
2486 	dev_attr = kmalloc(sizeof *dev_attr, GFP_KERNEL);
2487 	if (!dev_attr)
2488 		return;
2489 
2490 	if (ib_query_device(device, dev_attr)) {
2491 		pr_warn("Query device failed for %s\n", device->name);
2492 		goto free_attr;
2493 	}
2494 
2495 	srp_dev = kmalloc(sizeof *srp_dev, GFP_KERNEL);
2496 	if (!srp_dev)
2497 		goto free_attr;
2498 
2499 	/*
2500 	 * Use the smallest page size supported by the HCA, down to a
2501 	 * minimum of 4096 bytes. We're unlikely to build large sglists
2502 	 * out of smaller entries.
2503 	 */
2504 	fmr_page_shift		= max(12, ffs(dev_attr->page_size_cap) - 1);
2505 	srp_dev->fmr_page_size	= 1 << fmr_page_shift;
2506 	srp_dev->fmr_page_mask	= ~((u64) srp_dev->fmr_page_size - 1);
2507 	srp_dev->fmr_max_size	= srp_dev->fmr_page_size * SRP_FMR_SIZE;
2508 
2509 	INIT_LIST_HEAD(&srp_dev->dev_list);
2510 
2511 	srp_dev->dev = device;
2512 	srp_dev->pd  = ib_alloc_pd(device);
2513 	if (IS_ERR(srp_dev->pd))
2514 		goto free_dev;
2515 
2516 	srp_dev->mr = ib_get_dma_mr(srp_dev->pd,
2517 				    IB_ACCESS_LOCAL_WRITE |
2518 				    IB_ACCESS_REMOTE_READ |
2519 				    IB_ACCESS_REMOTE_WRITE);
2520 	if (IS_ERR(srp_dev->mr))
2521 		goto err_pd;
2522 
2523 	for (max_pages_per_fmr = SRP_FMR_SIZE;
2524 			max_pages_per_fmr >= SRP_FMR_MIN_SIZE;
2525 			max_pages_per_fmr /= 2, srp_dev->fmr_max_size /= 2) {
2526 		memset(&fmr_param, 0, sizeof fmr_param);
2527 		fmr_param.pool_size	    = SRP_FMR_POOL_SIZE;
2528 		fmr_param.dirty_watermark   = SRP_FMR_DIRTY_SIZE;
2529 		fmr_param.cache		    = 1;
2530 		fmr_param.max_pages_per_fmr = max_pages_per_fmr;
2531 		fmr_param.page_shift	    = fmr_page_shift;
2532 		fmr_param.access	    = (IB_ACCESS_LOCAL_WRITE |
2533 					       IB_ACCESS_REMOTE_WRITE |
2534 					       IB_ACCESS_REMOTE_READ);
2535 
2536 		srp_dev->fmr_pool = ib_create_fmr_pool(srp_dev->pd, &fmr_param);
2537 		if (!IS_ERR(srp_dev->fmr_pool))
2538 			break;
2539 	}
2540 
2541 	if (IS_ERR(srp_dev->fmr_pool))
2542 		srp_dev->fmr_pool = NULL;
2543 
2544 	if (device->node_type == RDMA_NODE_IB_SWITCH) {
2545 		s = 0;
2546 		e = 0;
2547 	} else {
2548 		s = 1;
2549 		e = device->phys_port_cnt;
2550 	}
2551 
2552 	for (p = s; p <= e; ++p) {
2553 		host = srp_add_port(srp_dev, p);
2554 		if (host)
2555 			list_add_tail(&host->list, &srp_dev->dev_list);
2556 	}
2557 
2558 	ib_set_client_data(device, &srp_client, srp_dev);
2559 
2560 	goto free_attr;
2561 
2562 err_pd:
2563 	ib_dealloc_pd(srp_dev->pd);
2564 
2565 free_dev:
2566 	kfree(srp_dev);
2567 
2568 free_attr:
2569 	kfree(dev_attr);
2570 }
2571 
2572 static void srp_remove_one(struct ib_device *device)
2573 {
2574 	struct srp_device *srp_dev;
2575 	struct srp_host *host, *tmp_host;
2576 	struct srp_target_port *target;
2577 
2578 	srp_dev = ib_get_client_data(device, &srp_client);
2579 	if (!srp_dev)
2580 		return;
2581 
2582 	list_for_each_entry_safe(host, tmp_host, &srp_dev->dev_list, list) {
2583 		device_unregister(&host->dev);
2584 		/*
2585 		 * Wait for the sysfs entry to go away, so that no new
2586 		 * target ports can be created.
2587 		 */
2588 		wait_for_completion(&host->released);
2589 
2590 		/*
2591 		 * Remove all target ports.
2592 		 */
2593 		spin_lock(&host->target_lock);
2594 		list_for_each_entry(target, &host->target_list, list)
2595 			srp_queue_remove_work(target);
2596 		spin_unlock(&host->target_lock);
2597 
2598 		/*
2599 		 * Wait for target port removal tasks.
2600 		 */
2601 		flush_workqueue(system_long_wq);
2602 
2603 		kfree(host);
2604 	}
2605 
2606 	if (srp_dev->fmr_pool)
2607 		ib_destroy_fmr_pool(srp_dev->fmr_pool);
2608 	ib_dereg_mr(srp_dev->mr);
2609 	ib_dealloc_pd(srp_dev->pd);
2610 
2611 	kfree(srp_dev);
2612 }
2613 
2614 static struct srp_function_template ib_srp_transport_functions = {
2615 	.rport_delete		 = srp_rport_delete,
2616 };
2617 
2618 static int __init srp_init_module(void)
2619 {
2620 	int ret;
2621 
2622 	BUILD_BUG_ON(FIELD_SIZEOF(struct ib_wc, wr_id) < sizeof(void *));
2623 
2624 	if (srp_sg_tablesize) {
2625 		pr_warn("srp_sg_tablesize is deprecated, please use cmd_sg_entries\n");
2626 		if (!cmd_sg_entries)
2627 			cmd_sg_entries = srp_sg_tablesize;
2628 	}
2629 
2630 	if (!cmd_sg_entries)
2631 		cmd_sg_entries = SRP_DEF_SG_TABLESIZE;
2632 
2633 	if (cmd_sg_entries > 255) {
2634 		pr_warn("Clamping cmd_sg_entries to 255\n");
2635 		cmd_sg_entries = 255;
2636 	}
2637 
2638 	if (!indirect_sg_entries)
2639 		indirect_sg_entries = cmd_sg_entries;
2640 	else if (indirect_sg_entries < cmd_sg_entries) {
2641 		pr_warn("Bumping up indirect_sg_entries to match cmd_sg_entries (%u)\n",
2642 			cmd_sg_entries);
2643 		indirect_sg_entries = cmd_sg_entries;
2644 	}
2645 
2646 	ib_srp_transport_template =
2647 		srp_attach_transport(&ib_srp_transport_functions);
2648 	if (!ib_srp_transport_template)
2649 		return -ENOMEM;
2650 
2651 	ret = class_register(&srp_class);
2652 	if (ret) {
2653 		pr_err("couldn't register class infiniband_srp\n");
2654 		srp_release_transport(ib_srp_transport_template);
2655 		return ret;
2656 	}
2657 
2658 	ib_sa_register_client(&srp_sa_client);
2659 
2660 	ret = ib_register_client(&srp_client);
2661 	if (ret) {
2662 		pr_err("couldn't register IB client\n");
2663 		srp_release_transport(ib_srp_transport_template);
2664 		ib_sa_unregister_client(&srp_sa_client);
2665 		class_unregister(&srp_class);
2666 		return ret;
2667 	}
2668 
2669 	return 0;
2670 }
2671 
2672 static void __exit srp_cleanup_module(void)
2673 {
2674 	ib_unregister_client(&srp_client);
2675 	ib_sa_unregister_client(&srp_sa_client);
2676 	class_unregister(&srp_class);
2677 	srp_release_transport(ib_srp_transport_template);
2678 }
2679 
2680 module_init(srp_init_module);
2681 module_exit(srp_cleanup_module);
2682