1 /*
2  * Copyright (c) 2006 - 2009 Mellanox Technology Inc.  All rights reserved.
3  * Copyright (C) 2008 - 2011 Bart Van Assche <bvanassche@acm.org>.
4  *
5  * This software is available to you under a choice of one of two
6  * licenses.  You may choose to be licensed under the terms of the GNU
7  * General Public License (GPL) Version 2, available from the file
8  * COPYING in the main directory of this source tree, or the
9  * OpenIB.org BSD license below:
10  *
11  *     Redistribution and use in source and binary forms, with or
12  *     without modification, are permitted provided that the following
13  *     conditions are met:
14  *
15  *      - Redistributions of source code must retain the above
16  *        copyright notice, this list of conditions and the following
17  *        disclaimer.
18  *
19  *      - Redistributions in binary form must reproduce the above
20  *        copyright notice, this list of conditions and the following
21  *        disclaimer in the documentation and/or other materials
22  *        provided with the distribution.
23  *
24  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
25  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
26  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
27  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
28  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
29  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
30  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
31  * SOFTWARE.
32  *
33  */
34 
35 #include <linux/module.h>
36 #include <linux/init.h>
37 #include <linux/slab.h>
38 #include <linux/err.h>
39 #include <linux/ctype.h>
40 #include <linux/kthread.h>
41 #include <linux/string.h>
42 #include <linux/delay.h>
43 #include <linux/atomic.h>
44 #include <linux/inet.h>
45 #include <rdma/ib_cache.h>
46 #include <scsi/scsi_proto.h>
47 #include <scsi/scsi_tcq.h>
48 #include <target/target_core_base.h>
49 #include <target/target_core_fabric.h>
50 #include "ib_srpt.h"
51 
52 /* Name of this kernel module. */
53 #define DRV_NAME		"ib_srpt"
54 #define DRV_VERSION		"2.0.0"
55 #define DRV_RELDATE		"2011-02-14"
56 
57 #define SRPT_ID_STRING	"Linux SRP target"
58 
59 #undef pr_fmt
60 #define pr_fmt(fmt) DRV_NAME " " fmt
61 
62 MODULE_AUTHOR("Vu Pham and Bart Van Assche");
63 MODULE_DESCRIPTION("InfiniBand SCSI RDMA Protocol target "
64 		   "v" DRV_VERSION " (" DRV_RELDATE ")");
65 MODULE_LICENSE("Dual BSD/GPL");
66 
67 /*
68  * Global Variables
69  */
70 
71 static u64 srpt_service_guid;
72 static DEFINE_SPINLOCK(srpt_dev_lock);	/* Protects srpt_dev_list. */
73 static LIST_HEAD(srpt_dev_list);	/* List of srpt_device structures. */
74 
75 static unsigned srp_max_req_size = DEFAULT_MAX_REQ_SIZE;
76 module_param(srp_max_req_size, int, 0444);
77 MODULE_PARM_DESC(srp_max_req_size,
78 		 "Maximum size of SRP request messages in bytes.");
79 
80 static int srpt_srq_size = DEFAULT_SRPT_SRQ_SIZE;
81 module_param(srpt_srq_size, int, 0444);
82 MODULE_PARM_DESC(srpt_srq_size,
83 		 "Shared receive queue (SRQ) size.");
84 
85 static int srpt_get_u64_x(char *buffer, const struct kernel_param *kp)
86 {
87 	return sprintf(buffer, "0x%016llx", *(u64 *)kp->arg);
88 }
89 module_param_call(srpt_service_guid, NULL, srpt_get_u64_x, &srpt_service_guid,
90 		  0444);
91 MODULE_PARM_DESC(srpt_service_guid,
92 		 "Using this value for ioc_guid, id_ext, and cm_listen_id"
93 		 " instead of using the node_guid of the first HCA.");
94 
95 static struct ib_client srpt_client;
96 /* Protects both rdma_cm_port and rdma_cm_id. */
97 static DEFINE_MUTEX(rdma_cm_mutex);
98 /* Port number RDMA/CM will bind to. */
99 static u16 rdma_cm_port;
100 static struct rdma_cm_id *rdma_cm_id;
101 static void srpt_release_cmd(struct se_cmd *se_cmd);
102 static void srpt_free_ch(struct kref *kref);
103 static int srpt_queue_status(struct se_cmd *cmd);
104 static void srpt_recv_done(struct ib_cq *cq, struct ib_wc *wc);
105 static void srpt_send_done(struct ib_cq *cq, struct ib_wc *wc);
106 static void srpt_process_wait_list(struct srpt_rdma_ch *ch);
107 
108 /*
109  * The only allowed channel state changes are those that change the channel
110  * state into a state with a higher numerical value. Hence the new > prev test.
111  */
112 static bool srpt_set_ch_state(struct srpt_rdma_ch *ch, enum rdma_ch_state new)
113 {
114 	unsigned long flags;
115 	enum rdma_ch_state prev;
116 	bool changed = false;
117 
118 	spin_lock_irqsave(&ch->spinlock, flags);
119 	prev = ch->state;
120 	if (new > prev) {
121 		ch->state = new;
122 		changed = true;
123 	}
124 	spin_unlock_irqrestore(&ch->spinlock, flags);
125 
126 	return changed;
127 }
128 
129 /**
130  * srpt_event_handler - asynchronous IB event callback function
131  * @handler: IB event handler registered by ib_register_event_handler().
132  * @event: Description of the event that occurred.
133  *
134  * Callback function called by the InfiniBand core when an asynchronous IB
135  * event occurs. This callback may occur in interrupt context. See also
136  * section 11.5.2, Set Asynchronous Event Handler in the InfiniBand
137  * Architecture Specification.
138  */
139 static void srpt_event_handler(struct ib_event_handler *handler,
140 			       struct ib_event *event)
141 {
142 	struct srpt_device *sdev;
143 	struct srpt_port *sport;
144 	u8 port_num;
145 
146 	sdev = ib_get_client_data(event->device, &srpt_client);
147 	if (!sdev || sdev->device != event->device)
148 		return;
149 
150 	pr_debug("ASYNC event= %d on device= %s\n", event->event,
151 		 sdev->device->name);
152 
153 	switch (event->event) {
154 	case IB_EVENT_PORT_ERR:
155 		port_num = event->element.port_num - 1;
156 		if (port_num < sdev->device->phys_port_cnt) {
157 			sport = &sdev->port[port_num];
158 			sport->lid = 0;
159 			sport->sm_lid = 0;
160 		} else {
161 			WARN(true, "event %d: port_num %d out of range 1..%d\n",
162 			     event->event, port_num + 1,
163 			     sdev->device->phys_port_cnt);
164 		}
165 		break;
166 	case IB_EVENT_PORT_ACTIVE:
167 	case IB_EVENT_LID_CHANGE:
168 	case IB_EVENT_PKEY_CHANGE:
169 	case IB_EVENT_SM_CHANGE:
170 	case IB_EVENT_CLIENT_REREGISTER:
171 	case IB_EVENT_GID_CHANGE:
172 		/* Refresh port data asynchronously. */
173 		port_num = event->element.port_num - 1;
174 		if (port_num < sdev->device->phys_port_cnt) {
175 			sport = &sdev->port[port_num];
176 			if (!sport->lid && !sport->sm_lid)
177 				schedule_work(&sport->work);
178 		} else {
179 			WARN(true, "event %d: port_num %d out of range 1..%d\n",
180 			     event->event, port_num + 1,
181 			     sdev->device->phys_port_cnt);
182 		}
183 		break;
184 	default:
185 		pr_err("received unrecognized IB event %d\n", event->event);
186 		break;
187 	}
188 }
189 
190 /**
191  * srpt_srq_event - SRQ event callback function
192  * @event: Description of the event that occurred.
193  * @ctx: Context pointer specified at SRQ creation time.
194  */
195 static void srpt_srq_event(struct ib_event *event, void *ctx)
196 {
197 	pr_debug("SRQ event %d\n", event->event);
198 }
199 
200 static const char *get_ch_state_name(enum rdma_ch_state s)
201 {
202 	switch (s) {
203 	case CH_CONNECTING:
204 		return "connecting";
205 	case CH_LIVE:
206 		return "live";
207 	case CH_DISCONNECTING:
208 		return "disconnecting";
209 	case CH_DRAINING:
210 		return "draining";
211 	case CH_DISCONNECTED:
212 		return "disconnected";
213 	}
214 	return "???";
215 }
216 
217 /**
218  * srpt_qp_event - QP event callback function
219  * @event: Description of the event that occurred.
220  * @ch: SRPT RDMA channel.
221  */
222 static void srpt_qp_event(struct ib_event *event, struct srpt_rdma_ch *ch)
223 {
224 	pr_debug("QP event %d on ch=%p sess_name=%s state=%d\n",
225 		 event->event, ch, ch->sess_name, ch->state);
226 
227 	switch (event->event) {
228 	case IB_EVENT_COMM_EST:
229 		if (ch->using_rdma_cm)
230 			rdma_notify(ch->rdma_cm.cm_id, event->event);
231 		else
232 			ib_cm_notify(ch->ib_cm.cm_id, event->event);
233 		break;
234 	case IB_EVENT_QP_LAST_WQE_REACHED:
235 		pr_debug("%s-%d, state %s: received Last WQE event.\n",
236 			 ch->sess_name, ch->qp->qp_num,
237 			 get_ch_state_name(ch->state));
238 		break;
239 	default:
240 		pr_err("received unrecognized IB QP event %d\n", event->event);
241 		break;
242 	}
243 }
244 
245 /**
246  * srpt_set_ioc - initialize a IOUnitInfo structure
247  * @c_list: controller list.
248  * @slot: one-based slot number.
249  * @value: four-bit value.
250  *
251  * Copies the lowest four bits of value in element slot of the array of four
252  * bit elements called c_list (controller list). The index slot is one-based.
253  */
254 static void srpt_set_ioc(u8 *c_list, u32 slot, u8 value)
255 {
256 	u16 id;
257 	u8 tmp;
258 
259 	id = (slot - 1) / 2;
260 	if (slot & 0x1) {
261 		tmp = c_list[id] & 0xf;
262 		c_list[id] = (value << 4) | tmp;
263 	} else {
264 		tmp = c_list[id] & 0xf0;
265 		c_list[id] = (value & 0xf) | tmp;
266 	}
267 }
268 
269 /**
270  * srpt_get_class_port_info - copy ClassPortInfo to a management datagram
271  * @mad: Datagram that will be sent as response to DM_ATTR_CLASS_PORT_INFO.
272  *
273  * See also section 16.3.3.1 ClassPortInfo in the InfiniBand Architecture
274  * Specification.
275  */
276 static void srpt_get_class_port_info(struct ib_dm_mad *mad)
277 {
278 	struct ib_class_port_info *cif;
279 
280 	cif = (struct ib_class_port_info *)mad->data;
281 	memset(cif, 0, sizeof(*cif));
282 	cif->base_version = 1;
283 	cif->class_version = 1;
284 
285 	ib_set_cpi_resp_time(cif, 20);
286 	mad->mad_hdr.status = 0;
287 }
288 
289 /**
290  * srpt_get_iou - write IOUnitInfo to a management datagram
291  * @mad: Datagram that will be sent as response to DM_ATTR_IOU_INFO.
292  *
293  * See also section 16.3.3.3 IOUnitInfo in the InfiniBand Architecture
294  * Specification. See also section B.7, table B.6 in the SRP r16a document.
295  */
296 static void srpt_get_iou(struct ib_dm_mad *mad)
297 {
298 	struct ib_dm_iou_info *ioui;
299 	u8 slot;
300 	int i;
301 
302 	ioui = (struct ib_dm_iou_info *)mad->data;
303 	ioui->change_id = cpu_to_be16(1);
304 	ioui->max_controllers = 16;
305 
306 	/* set present for slot 1 and empty for the rest */
307 	srpt_set_ioc(ioui->controller_list, 1, 1);
308 	for (i = 1, slot = 2; i < 16; i++, slot++)
309 		srpt_set_ioc(ioui->controller_list, slot, 0);
310 
311 	mad->mad_hdr.status = 0;
312 }
313 
314 /**
315  * srpt_get_ioc - write IOControllerprofile to a management datagram
316  * @sport: HCA port through which the MAD has been received.
317  * @slot: Slot number specified in DM_ATTR_IOC_PROFILE query.
318  * @mad: Datagram that will be sent as response to DM_ATTR_IOC_PROFILE.
319  *
320  * See also section 16.3.3.4 IOControllerProfile in the InfiniBand
321  * Architecture Specification. See also section B.7, table B.7 in the SRP
322  * r16a document.
323  */
324 static void srpt_get_ioc(struct srpt_port *sport, u32 slot,
325 			 struct ib_dm_mad *mad)
326 {
327 	struct srpt_device *sdev = sport->sdev;
328 	struct ib_dm_ioc_profile *iocp;
329 	int send_queue_depth;
330 
331 	iocp = (struct ib_dm_ioc_profile *)mad->data;
332 
333 	if (!slot || slot > 16) {
334 		mad->mad_hdr.status
335 			= cpu_to_be16(DM_MAD_STATUS_INVALID_FIELD);
336 		return;
337 	}
338 
339 	if (slot > 2) {
340 		mad->mad_hdr.status
341 			= cpu_to_be16(DM_MAD_STATUS_NO_IOC);
342 		return;
343 	}
344 
345 	if (sdev->use_srq)
346 		send_queue_depth = sdev->srq_size;
347 	else
348 		send_queue_depth = min(MAX_SRPT_RQ_SIZE,
349 				       sdev->device->attrs.max_qp_wr);
350 
351 	memset(iocp, 0, sizeof(*iocp));
352 	strcpy(iocp->id_string, SRPT_ID_STRING);
353 	iocp->guid = cpu_to_be64(srpt_service_guid);
354 	iocp->vendor_id = cpu_to_be32(sdev->device->attrs.vendor_id);
355 	iocp->device_id = cpu_to_be32(sdev->device->attrs.vendor_part_id);
356 	iocp->device_version = cpu_to_be16(sdev->device->attrs.hw_ver);
357 	iocp->subsys_vendor_id = cpu_to_be32(sdev->device->attrs.vendor_id);
358 	iocp->subsys_device_id = 0x0;
359 	iocp->io_class = cpu_to_be16(SRP_REV16A_IB_IO_CLASS);
360 	iocp->io_subclass = cpu_to_be16(SRP_IO_SUBCLASS);
361 	iocp->protocol = cpu_to_be16(SRP_PROTOCOL);
362 	iocp->protocol_version = cpu_to_be16(SRP_PROTOCOL_VERSION);
363 	iocp->send_queue_depth = cpu_to_be16(send_queue_depth);
364 	iocp->rdma_read_depth = 4;
365 	iocp->send_size = cpu_to_be32(srp_max_req_size);
366 	iocp->rdma_size = cpu_to_be32(min(sport->port_attrib.srp_max_rdma_size,
367 					  1U << 24));
368 	iocp->num_svc_entries = 1;
369 	iocp->op_cap_mask = SRP_SEND_TO_IOC | SRP_SEND_FROM_IOC |
370 		SRP_RDMA_READ_FROM_IOC | SRP_RDMA_WRITE_FROM_IOC;
371 
372 	mad->mad_hdr.status = 0;
373 }
374 
375 /**
376  * srpt_get_svc_entries - write ServiceEntries to a management datagram
377  * @ioc_guid: I/O controller GUID to use in reply.
378  * @slot: I/O controller number.
379  * @hi: End of the range of service entries to be specified in the reply.
380  * @lo: Start of the range of service entries to be specified in the reply..
381  * @mad: Datagram that will be sent as response to DM_ATTR_SVC_ENTRIES.
382  *
383  * See also section 16.3.3.5 ServiceEntries in the InfiniBand Architecture
384  * Specification. See also section B.7, table B.8 in the SRP r16a document.
385  */
386 static void srpt_get_svc_entries(u64 ioc_guid,
387 				 u16 slot, u8 hi, u8 lo, struct ib_dm_mad *mad)
388 {
389 	struct ib_dm_svc_entries *svc_entries;
390 
391 	WARN_ON(!ioc_guid);
392 
393 	if (!slot || slot > 16) {
394 		mad->mad_hdr.status
395 			= cpu_to_be16(DM_MAD_STATUS_INVALID_FIELD);
396 		return;
397 	}
398 
399 	if (slot > 2 || lo > hi || hi > 1) {
400 		mad->mad_hdr.status
401 			= cpu_to_be16(DM_MAD_STATUS_NO_IOC);
402 		return;
403 	}
404 
405 	svc_entries = (struct ib_dm_svc_entries *)mad->data;
406 	memset(svc_entries, 0, sizeof(*svc_entries));
407 	svc_entries->service_entries[0].id = cpu_to_be64(ioc_guid);
408 	snprintf(svc_entries->service_entries[0].name,
409 		 sizeof(svc_entries->service_entries[0].name),
410 		 "%s%016llx",
411 		 SRP_SERVICE_NAME_PREFIX,
412 		 ioc_guid);
413 
414 	mad->mad_hdr.status = 0;
415 }
416 
417 /**
418  * srpt_mgmt_method_get - process a received management datagram
419  * @sp:      HCA port through which the MAD has been received.
420  * @rq_mad:  received MAD.
421  * @rsp_mad: response MAD.
422  */
423 static void srpt_mgmt_method_get(struct srpt_port *sp, struct ib_mad *rq_mad,
424 				 struct ib_dm_mad *rsp_mad)
425 {
426 	u16 attr_id;
427 	u32 slot;
428 	u8 hi, lo;
429 
430 	attr_id = be16_to_cpu(rq_mad->mad_hdr.attr_id);
431 	switch (attr_id) {
432 	case DM_ATTR_CLASS_PORT_INFO:
433 		srpt_get_class_port_info(rsp_mad);
434 		break;
435 	case DM_ATTR_IOU_INFO:
436 		srpt_get_iou(rsp_mad);
437 		break;
438 	case DM_ATTR_IOC_PROFILE:
439 		slot = be32_to_cpu(rq_mad->mad_hdr.attr_mod);
440 		srpt_get_ioc(sp, slot, rsp_mad);
441 		break;
442 	case DM_ATTR_SVC_ENTRIES:
443 		slot = be32_to_cpu(rq_mad->mad_hdr.attr_mod);
444 		hi = (u8) ((slot >> 8) & 0xff);
445 		lo = (u8) (slot & 0xff);
446 		slot = (u16) ((slot >> 16) & 0xffff);
447 		srpt_get_svc_entries(srpt_service_guid,
448 				     slot, hi, lo, rsp_mad);
449 		break;
450 	default:
451 		rsp_mad->mad_hdr.status =
452 		    cpu_to_be16(DM_MAD_STATUS_UNSUP_METHOD_ATTR);
453 		break;
454 	}
455 }
456 
457 /**
458  * srpt_mad_send_handler - MAD send completion callback
459  * @mad_agent: Return value of ib_register_mad_agent().
460  * @mad_wc: Work completion reporting that the MAD has been sent.
461  */
462 static void srpt_mad_send_handler(struct ib_mad_agent *mad_agent,
463 				  struct ib_mad_send_wc *mad_wc)
464 {
465 	rdma_destroy_ah(mad_wc->send_buf->ah);
466 	ib_free_send_mad(mad_wc->send_buf);
467 }
468 
469 /**
470  * srpt_mad_recv_handler - MAD reception callback function
471  * @mad_agent: Return value of ib_register_mad_agent().
472  * @send_buf: Not used.
473  * @mad_wc: Work completion reporting that a MAD has been received.
474  */
475 static void srpt_mad_recv_handler(struct ib_mad_agent *mad_agent,
476 				  struct ib_mad_send_buf *send_buf,
477 				  struct ib_mad_recv_wc *mad_wc)
478 {
479 	struct srpt_port *sport = (struct srpt_port *)mad_agent->context;
480 	struct ib_ah *ah;
481 	struct ib_mad_send_buf *rsp;
482 	struct ib_dm_mad *dm_mad;
483 
484 	if (!mad_wc || !mad_wc->recv_buf.mad)
485 		return;
486 
487 	ah = ib_create_ah_from_wc(mad_agent->qp->pd, mad_wc->wc,
488 				  mad_wc->recv_buf.grh, mad_agent->port_num);
489 	if (IS_ERR(ah))
490 		goto err;
491 
492 	BUILD_BUG_ON(offsetof(struct ib_dm_mad, data) != IB_MGMT_DEVICE_HDR);
493 
494 	rsp = ib_create_send_mad(mad_agent, mad_wc->wc->src_qp,
495 				 mad_wc->wc->pkey_index, 0,
496 				 IB_MGMT_DEVICE_HDR, IB_MGMT_DEVICE_DATA,
497 				 GFP_KERNEL,
498 				 IB_MGMT_BASE_VERSION);
499 	if (IS_ERR(rsp))
500 		goto err_rsp;
501 
502 	rsp->ah = ah;
503 
504 	dm_mad = rsp->mad;
505 	memcpy(dm_mad, mad_wc->recv_buf.mad, sizeof(*dm_mad));
506 	dm_mad->mad_hdr.method = IB_MGMT_METHOD_GET_RESP;
507 	dm_mad->mad_hdr.status = 0;
508 
509 	switch (mad_wc->recv_buf.mad->mad_hdr.method) {
510 	case IB_MGMT_METHOD_GET:
511 		srpt_mgmt_method_get(sport, mad_wc->recv_buf.mad, dm_mad);
512 		break;
513 	case IB_MGMT_METHOD_SET:
514 		dm_mad->mad_hdr.status =
515 		    cpu_to_be16(DM_MAD_STATUS_UNSUP_METHOD_ATTR);
516 		break;
517 	default:
518 		dm_mad->mad_hdr.status =
519 		    cpu_to_be16(DM_MAD_STATUS_UNSUP_METHOD);
520 		break;
521 	}
522 
523 	if (!ib_post_send_mad(rsp, NULL)) {
524 		ib_free_recv_mad(mad_wc);
525 		/* will destroy_ah & free_send_mad in send completion */
526 		return;
527 	}
528 
529 	ib_free_send_mad(rsp);
530 
531 err_rsp:
532 	rdma_destroy_ah(ah);
533 err:
534 	ib_free_recv_mad(mad_wc);
535 }
536 
537 static int srpt_format_guid(char *buf, unsigned int size, const __be64 *guid)
538 {
539 	const __be16 *g = (const __be16 *)guid;
540 
541 	return snprintf(buf, size, "%04x:%04x:%04x:%04x",
542 			be16_to_cpu(g[0]), be16_to_cpu(g[1]),
543 			be16_to_cpu(g[2]), be16_to_cpu(g[3]));
544 }
545 
546 /**
547  * srpt_refresh_port - configure a HCA port
548  * @sport: SRPT HCA port.
549  *
550  * Enable InfiniBand management datagram processing, update the cached sm_lid,
551  * lid and gid values, and register a callback function for processing MADs
552  * on the specified port.
553  *
554  * Note: It is safe to call this function more than once for the same port.
555  */
556 static int srpt_refresh_port(struct srpt_port *sport)
557 {
558 	struct ib_mad_reg_req reg_req;
559 	struct ib_port_modify port_modify;
560 	struct ib_port_attr port_attr;
561 	int ret;
562 
563 	memset(&port_modify, 0, sizeof(port_modify));
564 	port_modify.set_port_cap_mask = IB_PORT_DEVICE_MGMT_SUP;
565 	port_modify.clr_port_cap_mask = 0;
566 
567 	ret = ib_modify_port(sport->sdev->device, sport->port, 0, &port_modify);
568 	if (ret)
569 		goto err_mod_port;
570 
571 	ret = ib_query_port(sport->sdev->device, sport->port, &port_attr);
572 	if (ret)
573 		goto err_query_port;
574 
575 	sport->sm_lid = port_attr.sm_lid;
576 	sport->lid = port_attr.lid;
577 
578 	ret = rdma_query_gid(sport->sdev->device, sport->port, 0, &sport->gid);
579 	if (ret)
580 		goto err_query_port;
581 
582 	sport->port_guid_wwn.priv = sport;
583 	srpt_format_guid(sport->port_guid, sizeof(sport->port_guid),
584 			 &sport->gid.global.interface_id);
585 	sport->port_gid_wwn.priv = sport;
586 	snprintf(sport->port_gid, sizeof(sport->port_gid),
587 		 "0x%016llx%016llx",
588 		 be64_to_cpu(sport->gid.global.subnet_prefix),
589 		 be64_to_cpu(sport->gid.global.interface_id));
590 
591 	if (!sport->mad_agent) {
592 		memset(&reg_req, 0, sizeof(reg_req));
593 		reg_req.mgmt_class = IB_MGMT_CLASS_DEVICE_MGMT;
594 		reg_req.mgmt_class_version = IB_MGMT_BASE_VERSION;
595 		set_bit(IB_MGMT_METHOD_GET, reg_req.method_mask);
596 		set_bit(IB_MGMT_METHOD_SET, reg_req.method_mask);
597 
598 		sport->mad_agent = ib_register_mad_agent(sport->sdev->device,
599 							 sport->port,
600 							 IB_QPT_GSI,
601 							 &reg_req, 0,
602 							 srpt_mad_send_handler,
603 							 srpt_mad_recv_handler,
604 							 sport, 0);
605 		if (IS_ERR(sport->mad_agent)) {
606 			ret = PTR_ERR(sport->mad_agent);
607 			sport->mad_agent = NULL;
608 			goto err_query_port;
609 		}
610 	}
611 
612 	return 0;
613 
614 err_query_port:
615 
616 	port_modify.set_port_cap_mask = 0;
617 	port_modify.clr_port_cap_mask = IB_PORT_DEVICE_MGMT_SUP;
618 	ib_modify_port(sport->sdev->device, sport->port, 0, &port_modify);
619 
620 err_mod_port:
621 
622 	return ret;
623 }
624 
625 /**
626  * srpt_unregister_mad_agent - unregister MAD callback functions
627  * @sdev: SRPT HCA pointer.
628  *
629  * Note: It is safe to call this function more than once for the same device.
630  */
631 static void srpt_unregister_mad_agent(struct srpt_device *sdev)
632 {
633 	struct ib_port_modify port_modify = {
634 		.clr_port_cap_mask = IB_PORT_DEVICE_MGMT_SUP,
635 	};
636 	struct srpt_port *sport;
637 	int i;
638 
639 	for (i = 1; i <= sdev->device->phys_port_cnt; i++) {
640 		sport = &sdev->port[i - 1];
641 		WARN_ON(sport->port != i);
642 		if (ib_modify_port(sdev->device, i, 0, &port_modify) < 0)
643 			pr_err("disabling MAD processing failed.\n");
644 		if (sport->mad_agent) {
645 			ib_unregister_mad_agent(sport->mad_agent);
646 			sport->mad_agent = NULL;
647 		}
648 	}
649 }
650 
651 /**
652  * srpt_alloc_ioctx - allocate a SRPT I/O context structure
653  * @sdev: SRPT HCA pointer.
654  * @ioctx_size: I/O context size.
655  * @dma_size: Size of I/O context DMA buffer.
656  * @dir: DMA data direction.
657  */
658 static struct srpt_ioctx *srpt_alloc_ioctx(struct srpt_device *sdev,
659 					   int ioctx_size, int dma_size,
660 					   enum dma_data_direction dir)
661 {
662 	struct srpt_ioctx *ioctx;
663 
664 	ioctx = kmalloc(ioctx_size, GFP_KERNEL);
665 	if (!ioctx)
666 		goto err;
667 
668 	ioctx->buf = kmalloc(dma_size, GFP_KERNEL);
669 	if (!ioctx->buf)
670 		goto err_free_ioctx;
671 
672 	ioctx->dma = ib_dma_map_single(sdev->device, ioctx->buf, dma_size, dir);
673 	if (ib_dma_mapping_error(sdev->device, ioctx->dma))
674 		goto err_free_buf;
675 
676 	return ioctx;
677 
678 err_free_buf:
679 	kfree(ioctx->buf);
680 err_free_ioctx:
681 	kfree(ioctx);
682 err:
683 	return NULL;
684 }
685 
686 /**
687  * srpt_free_ioctx - free a SRPT I/O context structure
688  * @sdev: SRPT HCA pointer.
689  * @ioctx: I/O context pointer.
690  * @dma_size: Size of I/O context DMA buffer.
691  * @dir: DMA data direction.
692  */
693 static void srpt_free_ioctx(struct srpt_device *sdev, struct srpt_ioctx *ioctx,
694 			    int dma_size, enum dma_data_direction dir)
695 {
696 	if (!ioctx)
697 		return;
698 
699 	ib_dma_unmap_single(sdev->device, ioctx->dma, dma_size, dir);
700 	kfree(ioctx->buf);
701 	kfree(ioctx);
702 }
703 
704 /**
705  * srpt_alloc_ioctx_ring - allocate a ring of SRPT I/O context structures
706  * @sdev:       Device to allocate the I/O context ring for.
707  * @ring_size:  Number of elements in the I/O context ring.
708  * @ioctx_size: I/O context size.
709  * @dma_size:   DMA buffer size.
710  * @dir:        DMA data direction.
711  */
712 static struct srpt_ioctx **srpt_alloc_ioctx_ring(struct srpt_device *sdev,
713 				int ring_size, int ioctx_size,
714 				int dma_size, enum dma_data_direction dir)
715 {
716 	struct srpt_ioctx **ring;
717 	int i;
718 
719 	WARN_ON(ioctx_size != sizeof(struct srpt_recv_ioctx)
720 		&& ioctx_size != sizeof(struct srpt_send_ioctx));
721 
722 	ring = kvmalloc_array(ring_size, sizeof(ring[0]), GFP_KERNEL);
723 	if (!ring)
724 		goto out;
725 	for (i = 0; i < ring_size; ++i) {
726 		ring[i] = srpt_alloc_ioctx(sdev, ioctx_size, dma_size, dir);
727 		if (!ring[i])
728 			goto err;
729 		ring[i]->index = i;
730 	}
731 	goto out;
732 
733 err:
734 	while (--i >= 0)
735 		srpt_free_ioctx(sdev, ring[i], dma_size, dir);
736 	kvfree(ring);
737 	ring = NULL;
738 out:
739 	return ring;
740 }
741 
742 /**
743  * srpt_free_ioctx_ring - free the ring of SRPT I/O context structures
744  * @ioctx_ring: I/O context ring to be freed.
745  * @sdev: SRPT HCA pointer.
746  * @ring_size: Number of ring elements.
747  * @dma_size: Size of I/O context DMA buffer.
748  * @dir: DMA data direction.
749  */
750 static void srpt_free_ioctx_ring(struct srpt_ioctx **ioctx_ring,
751 				 struct srpt_device *sdev, int ring_size,
752 				 int dma_size, enum dma_data_direction dir)
753 {
754 	int i;
755 
756 	if (!ioctx_ring)
757 		return;
758 
759 	for (i = 0; i < ring_size; ++i)
760 		srpt_free_ioctx(sdev, ioctx_ring[i], dma_size, dir);
761 	kvfree(ioctx_ring);
762 }
763 
764 /**
765  * srpt_set_cmd_state - set the state of a SCSI command
766  * @ioctx: Send I/O context.
767  * @new: New I/O context state.
768  *
769  * Does not modify the state of aborted commands. Returns the previous command
770  * state.
771  */
772 static enum srpt_command_state srpt_set_cmd_state(struct srpt_send_ioctx *ioctx,
773 						  enum srpt_command_state new)
774 {
775 	enum srpt_command_state previous;
776 
777 	previous = ioctx->state;
778 	if (previous != SRPT_STATE_DONE)
779 		ioctx->state = new;
780 
781 	return previous;
782 }
783 
784 /**
785  * srpt_test_and_set_cmd_state - test and set the state of a command
786  * @ioctx: Send I/O context.
787  * @old: Current I/O context state.
788  * @new: New I/O context state.
789  *
790  * Returns true if and only if the previous command state was equal to 'old'.
791  */
792 static bool srpt_test_and_set_cmd_state(struct srpt_send_ioctx *ioctx,
793 					enum srpt_command_state old,
794 					enum srpt_command_state new)
795 {
796 	enum srpt_command_state previous;
797 
798 	WARN_ON(!ioctx);
799 	WARN_ON(old == SRPT_STATE_DONE);
800 	WARN_ON(new == SRPT_STATE_NEW);
801 
802 	previous = ioctx->state;
803 	if (previous == old)
804 		ioctx->state = new;
805 
806 	return previous == old;
807 }
808 
809 /**
810  * srpt_post_recv - post an IB receive request
811  * @sdev: SRPT HCA pointer.
812  * @ch: SRPT RDMA channel.
813  * @ioctx: Receive I/O context pointer.
814  */
815 static int srpt_post_recv(struct srpt_device *sdev, struct srpt_rdma_ch *ch,
816 			  struct srpt_recv_ioctx *ioctx)
817 {
818 	struct ib_sge list;
819 	struct ib_recv_wr wr;
820 
821 	BUG_ON(!sdev);
822 	list.addr = ioctx->ioctx.dma;
823 	list.length = srp_max_req_size;
824 	list.lkey = sdev->lkey;
825 
826 	ioctx->ioctx.cqe.done = srpt_recv_done;
827 	wr.wr_cqe = &ioctx->ioctx.cqe;
828 	wr.next = NULL;
829 	wr.sg_list = &list;
830 	wr.num_sge = 1;
831 
832 	if (sdev->use_srq)
833 		return ib_post_srq_recv(sdev->srq, &wr, NULL);
834 	else
835 		return ib_post_recv(ch->qp, &wr, NULL);
836 }
837 
838 /**
839  * srpt_zerolength_write - perform a zero-length RDMA write
840  * @ch: SRPT RDMA channel.
841  *
842  * A quote from the InfiniBand specification: C9-88: For an HCA responder
843  * using Reliable Connection service, for each zero-length RDMA READ or WRITE
844  * request, the R_Key shall not be validated, even if the request includes
845  * Immediate data.
846  */
847 static int srpt_zerolength_write(struct srpt_rdma_ch *ch)
848 {
849 	struct ib_rdma_wr wr = {
850 		.wr = {
851 			.next		= NULL,
852 			{ .wr_cqe	= &ch->zw_cqe, },
853 			.opcode		= IB_WR_RDMA_WRITE,
854 			.send_flags	= IB_SEND_SIGNALED,
855 		}
856 	};
857 
858 	pr_debug("%s-%d: queued zerolength write\n", ch->sess_name,
859 		 ch->qp->qp_num);
860 
861 	return ib_post_send(ch->qp, &wr.wr, NULL);
862 }
863 
864 static void srpt_zerolength_write_done(struct ib_cq *cq, struct ib_wc *wc)
865 {
866 	struct srpt_rdma_ch *ch = cq->cq_context;
867 
868 	pr_debug("%s-%d wc->status %d\n", ch->sess_name, ch->qp->qp_num,
869 		 wc->status);
870 
871 	if (wc->status == IB_WC_SUCCESS) {
872 		srpt_process_wait_list(ch);
873 	} else {
874 		if (srpt_set_ch_state(ch, CH_DISCONNECTED))
875 			schedule_work(&ch->release_work);
876 		else
877 			pr_debug("%s-%d: already disconnected.\n",
878 				 ch->sess_name, ch->qp->qp_num);
879 	}
880 }
881 
882 static int srpt_alloc_rw_ctxs(struct srpt_send_ioctx *ioctx,
883 		struct srp_direct_buf *db, int nbufs, struct scatterlist **sg,
884 		unsigned *sg_cnt)
885 {
886 	enum dma_data_direction dir = target_reverse_dma_direction(&ioctx->cmd);
887 	struct srpt_rdma_ch *ch = ioctx->ch;
888 	struct scatterlist *prev = NULL;
889 	unsigned prev_nents;
890 	int ret, i;
891 
892 	if (nbufs == 1) {
893 		ioctx->rw_ctxs = &ioctx->s_rw_ctx;
894 	} else {
895 		ioctx->rw_ctxs = kmalloc_array(nbufs, sizeof(*ioctx->rw_ctxs),
896 			GFP_KERNEL);
897 		if (!ioctx->rw_ctxs)
898 			return -ENOMEM;
899 	}
900 
901 	for (i = ioctx->n_rw_ctx; i < nbufs; i++, db++) {
902 		struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
903 		u64 remote_addr = be64_to_cpu(db->va);
904 		u32 size = be32_to_cpu(db->len);
905 		u32 rkey = be32_to_cpu(db->key);
906 
907 		ret = target_alloc_sgl(&ctx->sg, &ctx->nents, size, false,
908 				i < nbufs - 1);
909 		if (ret)
910 			goto unwind;
911 
912 		ret = rdma_rw_ctx_init(&ctx->rw, ch->qp, ch->sport->port,
913 				ctx->sg, ctx->nents, 0, remote_addr, rkey, dir);
914 		if (ret < 0) {
915 			target_free_sgl(ctx->sg, ctx->nents);
916 			goto unwind;
917 		}
918 
919 		ioctx->n_rdma += ret;
920 		ioctx->n_rw_ctx++;
921 
922 		if (prev) {
923 			sg_unmark_end(&prev[prev_nents - 1]);
924 			sg_chain(prev, prev_nents + 1, ctx->sg);
925 		} else {
926 			*sg = ctx->sg;
927 		}
928 
929 		prev = ctx->sg;
930 		prev_nents = ctx->nents;
931 
932 		*sg_cnt += ctx->nents;
933 	}
934 
935 	return 0;
936 
937 unwind:
938 	while (--i >= 0) {
939 		struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
940 
941 		rdma_rw_ctx_destroy(&ctx->rw, ch->qp, ch->sport->port,
942 				ctx->sg, ctx->nents, dir);
943 		target_free_sgl(ctx->sg, ctx->nents);
944 	}
945 	if (ioctx->rw_ctxs != &ioctx->s_rw_ctx)
946 		kfree(ioctx->rw_ctxs);
947 	return ret;
948 }
949 
950 static void srpt_free_rw_ctxs(struct srpt_rdma_ch *ch,
951 				    struct srpt_send_ioctx *ioctx)
952 {
953 	enum dma_data_direction dir = target_reverse_dma_direction(&ioctx->cmd);
954 	int i;
955 
956 	for (i = 0; i < ioctx->n_rw_ctx; i++) {
957 		struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
958 
959 		rdma_rw_ctx_destroy(&ctx->rw, ch->qp, ch->sport->port,
960 				ctx->sg, ctx->nents, dir);
961 		target_free_sgl(ctx->sg, ctx->nents);
962 	}
963 
964 	if (ioctx->rw_ctxs != &ioctx->s_rw_ctx)
965 		kfree(ioctx->rw_ctxs);
966 }
967 
968 static inline void *srpt_get_desc_buf(struct srp_cmd *srp_cmd)
969 {
970 	/*
971 	 * The pointer computations below will only be compiled correctly
972 	 * if srp_cmd::add_data is declared as s8*, u8*, s8[] or u8[], so check
973 	 * whether srp_cmd::add_data has been declared as a byte pointer.
974 	 */
975 	BUILD_BUG_ON(!__same_type(srp_cmd->add_data[0], (s8)0) &&
976 		     !__same_type(srp_cmd->add_data[0], (u8)0));
977 
978 	/*
979 	 * According to the SRP spec, the lower two bits of the 'ADDITIONAL
980 	 * CDB LENGTH' field are reserved and the size in bytes of this field
981 	 * is four times the value specified in bits 3..7. Hence the "& ~3".
982 	 */
983 	return srp_cmd->add_data + (srp_cmd->add_cdb_len & ~3);
984 }
985 
986 /**
987  * srpt_get_desc_tbl - parse the data descriptors of a SRP_CMD request
988  * @ioctx: Pointer to the I/O context associated with the request.
989  * @srp_cmd: Pointer to the SRP_CMD request data.
990  * @dir: Pointer to the variable to which the transfer direction will be
991  *   written.
992  * @sg: [out] scatterlist allocated for the parsed SRP_CMD.
993  * @sg_cnt: [out] length of @sg.
994  * @data_len: Pointer to the variable to which the total data length of all
995  *   descriptors in the SRP_CMD request will be written.
996  *
997  * This function initializes ioctx->nrbuf and ioctx->r_bufs.
998  *
999  * Returns -EINVAL when the SRP_CMD request contains inconsistent descriptors;
1000  * -ENOMEM when memory allocation fails and zero upon success.
1001  */
1002 static int srpt_get_desc_tbl(struct srpt_send_ioctx *ioctx,
1003 		struct srp_cmd *srp_cmd, enum dma_data_direction *dir,
1004 		struct scatterlist **sg, unsigned *sg_cnt, u64 *data_len)
1005 {
1006 	BUG_ON(!dir);
1007 	BUG_ON(!data_len);
1008 
1009 	/*
1010 	 * The lower four bits of the buffer format field contain the DATA-IN
1011 	 * buffer descriptor format, and the highest four bits contain the
1012 	 * DATA-OUT buffer descriptor format.
1013 	 */
1014 	if (srp_cmd->buf_fmt & 0xf)
1015 		/* DATA-IN: transfer data from target to initiator (read). */
1016 		*dir = DMA_FROM_DEVICE;
1017 	else if (srp_cmd->buf_fmt >> 4)
1018 		/* DATA-OUT: transfer data from initiator to target (write). */
1019 		*dir = DMA_TO_DEVICE;
1020 	else
1021 		*dir = DMA_NONE;
1022 
1023 	/* initialize data_direction early as srpt_alloc_rw_ctxs needs it */
1024 	ioctx->cmd.data_direction = *dir;
1025 
1026 	if (((srp_cmd->buf_fmt & 0xf) == SRP_DATA_DESC_DIRECT) ||
1027 	    ((srp_cmd->buf_fmt >> 4) == SRP_DATA_DESC_DIRECT)) {
1028 	    	struct srp_direct_buf *db = srpt_get_desc_buf(srp_cmd);
1029 
1030 		*data_len = be32_to_cpu(db->len);
1031 		return srpt_alloc_rw_ctxs(ioctx, db, 1, sg, sg_cnt);
1032 	} else if (((srp_cmd->buf_fmt & 0xf) == SRP_DATA_DESC_INDIRECT) ||
1033 		   ((srp_cmd->buf_fmt >> 4) == SRP_DATA_DESC_INDIRECT)) {
1034 		struct srp_indirect_buf *idb = srpt_get_desc_buf(srp_cmd);
1035 		int nbufs = be32_to_cpu(idb->table_desc.len) /
1036 				sizeof(struct srp_direct_buf);
1037 
1038 		if (nbufs >
1039 		    (srp_cmd->data_out_desc_cnt + srp_cmd->data_in_desc_cnt)) {
1040 			pr_err("received unsupported SRP_CMD request"
1041 			       " type (%u out + %u in != %u / %zu)\n",
1042 			       srp_cmd->data_out_desc_cnt,
1043 			       srp_cmd->data_in_desc_cnt,
1044 			       be32_to_cpu(idb->table_desc.len),
1045 			       sizeof(struct srp_direct_buf));
1046 			return -EINVAL;
1047 		}
1048 
1049 		*data_len = be32_to_cpu(idb->len);
1050 		return srpt_alloc_rw_ctxs(ioctx, idb->desc_list, nbufs,
1051 				sg, sg_cnt);
1052 	} else {
1053 		*data_len = 0;
1054 		return 0;
1055 	}
1056 }
1057 
1058 /**
1059  * srpt_init_ch_qp - initialize queue pair attributes
1060  * @ch: SRPT RDMA channel.
1061  * @qp: Queue pair pointer.
1062  *
1063  * Initialized the attributes of queue pair 'qp' by allowing local write,
1064  * remote read and remote write. Also transitions 'qp' to state IB_QPS_INIT.
1065  */
1066 static int srpt_init_ch_qp(struct srpt_rdma_ch *ch, struct ib_qp *qp)
1067 {
1068 	struct ib_qp_attr *attr;
1069 	int ret;
1070 
1071 	WARN_ON_ONCE(ch->using_rdma_cm);
1072 
1073 	attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1074 	if (!attr)
1075 		return -ENOMEM;
1076 
1077 	attr->qp_state = IB_QPS_INIT;
1078 	attr->qp_access_flags = IB_ACCESS_LOCAL_WRITE;
1079 	attr->port_num = ch->sport->port;
1080 
1081 	ret = ib_find_cached_pkey(ch->sport->sdev->device, ch->sport->port,
1082 				  ch->pkey, &attr->pkey_index);
1083 	if (ret < 0)
1084 		pr_err("Translating pkey %#x failed (%d) - using index 0\n",
1085 		       ch->pkey, ret);
1086 
1087 	ret = ib_modify_qp(qp, attr,
1088 			   IB_QP_STATE | IB_QP_ACCESS_FLAGS | IB_QP_PORT |
1089 			   IB_QP_PKEY_INDEX);
1090 
1091 	kfree(attr);
1092 	return ret;
1093 }
1094 
1095 /**
1096  * srpt_ch_qp_rtr - change the state of a channel to 'ready to receive' (RTR)
1097  * @ch: channel of the queue pair.
1098  * @qp: queue pair to change the state of.
1099  *
1100  * Returns zero upon success and a negative value upon failure.
1101  *
1102  * Note: currently a struct ib_qp_attr takes 136 bytes on a 64-bit system.
1103  * If this structure ever becomes larger, it might be necessary to allocate
1104  * it dynamically instead of on the stack.
1105  */
1106 static int srpt_ch_qp_rtr(struct srpt_rdma_ch *ch, struct ib_qp *qp)
1107 {
1108 	struct ib_qp_attr qp_attr;
1109 	int attr_mask;
1110 	int ret;
1111 
1112 	WARN_ON_ONCE(ch->using_rdma_cm);
1113 
1114 	qp_attr.qp_state = IB_QPS_RTR;
1115 	ret = ib_cm_init_qp_attr(ch->ib_cm.cm_id, &qp_attr, &attr_mask);
1116 	if (ret)
1117 		goto out;
1118 
1119 	qp_attr.max_dest_rd_atomic = 4;
1120 
1121 	ret = ib_modify_qp(qp, &qp_attr, attr_mask);
1122 
1123 out:
1124 	return ret;
1125 }
1126 
1127 /**
1128  * srpt_ch_qp_rts - change the state of a channel to 'ready to send' (RTS)
1129  * @ch: channel of the queue pair.
1130  * @qp: queue pair to change the state of.
1131  *
1132  * Returns zero upon success and a negative value upon failure.
1133  *
1134  * Note: currently a struct ib_qp_attr takes 136 bytes on a 64-bit system.
1135  * If this structure ever becomes larger, it might be necessary to allocate
1136  * it dynamically instead of on the stack.
1137  */
1138 static int srpt_ch_qp_rts(struct srpt_rdma_ch *ch, struct ib_qp *qp)
1139 {
1140 	struct ib_qp_attr qp_attr;
1141 	int attr_mask;
1142 	int ret;
1143 
1144 	qp_attr.qp_state = IB_QPS_RTS;
1145 	ret = ib_cm_init_qp_attr(ch->ib_cm.cm_id, &qp_attr, &attr_mask);
1146 	if (ret)
1147 		goto out;
1148 
1149 	qp_attr.max_rd_atomic = 4;
1150 
1151 	ret = ib_modify_qp(qp, &qp_attr, attr_mask);
1152 
1153 out:
1154 	return ret;
1155 }
1156 
1157 /**
1158  * srpt_ch_qp_err - set the channel queue pair state to 'error'
1159  * @ch: SRPT RDMA channel.
1160  */
1161 static int srpt_ch_qp_err(struct srpt_rdma_ch *ch)
1162 {
1163 	struct ib_qp_attr qp_attr;
1164 
1165 	qp_attr.qp_state = IB_QPS_ERR;
1166 	return ib_modify_qp(ch->qp, &qp_attr, IB_QP_STATE);
1167 }
1168 
1169 /**
1170  * srpt_get_send_ioctx - obtain an I/O context for sending to the initiator
1171  * @ch: SRPT RDMA channel.
1172  */
1173 static struct srpt_send_ioctx *srpt_get_send_ioctx(struct srpt_rdma_ch *ch)
1174 {
1175 	struct srpt_send_ioctx *ioctx;
1176 	unsigned long flags;
1177 
1178 	BUG_ON(!ch);
1179 
1180 	ioctx = NULL;
1181 	spin_lock_irqsave(&ch->spinlock, flags);
1182 	if (!list_empty(&ch->free_list)) {
1183 		ioctx = list_first_entry(&ch->free_list,
1184 					 struct srpt_send_ioctx, free_list);
1185 		list_del(&ioctx->free_list);
1186 	}
1187 	spin_unlock_irqrestore(&ch->spinlock, flags);
1188 
1189 	if (!ioctx)
1190 		return ioctx;
1191 
1192 	BUG_ON(ioctx->ch != ch);
1193 	ioctx->state = SRPT_STATE_NEW;
1194 	ioctx->n_rdma = 0;
1195 	ioctx->n_rw_ctx = 0;
1196 	ioctx->queue_status_only = false;
1197 	/*
1198 	 * transport_init_se_cmd() does not initialize all fields, so do it
1199 	 * here.
1200 	 */
1201 	memset(&ioctx->cmd, 0, sizeof(ioctx->cmd));
1202 	memset(&ioctx->sense_data, 0, sizeof(ioctx->sense_data));
1203 
1204 	return ioctx;
1205 }
1206 
1207 /**
1208  * srpt_abort_cmd - abort a SCSI command
1209  * @ioctx:   I/O context associated with the SCSI command.
1210  */
1211 static int srpt_abort_cmd(struct srpt_send_ioctx *ioctx)
1212 {
1213 	enum srpt_command_state state;
1214 
1215 	BUG_ON(!ioctx);
1216 
1217 	/*
1218 	 * If the command is in a state where the target core is waiting for
1219 	 * the ib_srpt driver, change the state to the next state.
1220 	 */
1221 
1222 	state = ioctx->state;
1223 	switch (state) {
1224 	case SRPT_STATE_NEED_DATA:
1225 		ioctx->state = SRPT_STATE_DATA_IN;
1226 		break;
1227 	case SRPT_STATE_CMD_RSP_SENT:
1228 	case SRPT_STATE_MGMT_RSP_SENT:
1229 		ioctx->state = SRPT_STATE_DONE;
1230 		break;
1231 	default:
1232 		WARN_ONCE(true, "%s: unexpected I/O context state %d\n",
1233 			  __func__, state);
1234 		break;
1235 	}
1236 
1237 	pr_debug("Aborting cmd with state %d -> %d and tag %lld\n", state,
1238 		 ioctx->state, ioctx->cmd.tag);
1239 
1240 	switch (state) {
1241 	case SRPT_STATE_NEW:
1242 	case SRPT_STATE_DATA_IN:
1243 	case SRPT_STATE_MGMT:
1244 	case SRPT_STATE_DONE:
1245 		/*
1246 		 * Do nothing - defer abort processing until
1247 		 * srpt_queue_response() is invoked.
1248 		 */
1249 		break;
1250 	case SRPT_STATE_NEED_DATA:
1251 		pr_debug("tag %#llx: RDMA read error\n", ioctx->cmd.tag);
1252 		transport_generic_request_failure(&ioctx->cmd,
1253 					TCM_CHECK_CONDITION_ABORT_CMD);
1254 		break;
1255 	case SRPT_STATE_CMD_RSP_SENT:
1256 		/*
1257 		 * SRP_RSP sending failed or the SRP_RSP send completion has
1258 		 * not been received in time.
1259 		 */
1260 		transport_generic_free_cmd(&ioctx->cmd, 0);
1261 		break;
1262 	case SRPT_STATE_MGMT_RSP_SENT:
1263 		transport_generic_free_cmd(&ioctx->cmd, 0);
1264 		break;
1265 	default:
1266 		WARN(1, "Unexpected command state (%d)", state);
1267 		break;
1268 	}
1269 
1270 	return state;
1271 }
1272 
1273 /**
1274  * srpt_rdma_read_done - RDMA read completion callback
1275  * @cq: Completion queue.
1276  * @wc: Work completion.
1277  *
1278  * XXX: what is now target_execute_cmd used to be asynchronous, and unmapping
1279  * the data that has been transferred via IB RDMA had to be postponed until the
1280  * check_stop_free() callback.  None of this is necessary anymore and needs to
1281  * be cleaned up.
1282  */
1283 static void srpt_rdma_read_done(struct ib_cq *cq, struct ib_wc *wc)
1284 {
1285 	struct srpt_rdma_ch *ch = cq->cq_context;
1286 	struct srpt_send_ioctx *ioctx =
1287 		container_of(wc->wr_cqe, struct srpt_send_ioctx, rdma_cqe);
1288 
1289 	WARN_ON(ioctx->n_rdma <= 0);
1290 	atomic_add(ioctx->n_rdma, &ch->sq_wr_avail);
1291 	ioctx->n_rdma = 0;
1292 
1293 	if (unlikely(wc->status != IB_WC_SUCCESS)) {
1294 		pr_info("RDMA_READ for ioctx 0x%p failed with status %d\n",
1295 			ioctx, wc->status);
1296 		srpt_abort_cmd(ioctx);
1297 		return;
1298 	}
1299 
1300 	if (srpt_test_and_set_cmd_state(ioctx, SRPT_STATE_NEED_DATA,
1301 					SRPT_STATE_DATA_IN))
1302 		target_execute_cmd(&ioctx->cmd);
1303 	else
1304 		pr_err("%s[%d]: wrong state = %d\n", __func__,
1305 		       __LINE__, ioctx->state);
1306 }
1307 
1308 /**
1309  * srpt_build_cmd_rsp - build a SRP_RSP response
1310  * @ch: RDMA channel through which the request has been received.
1311  * @ioctx: I/O context associated with the SRP_CMD request. The response will
1312  *   be built in the buffer ioctx->buf points at and hence this function will
1313  *   overwrite the request data.
1314  * @tag: tag of the request for which this response is being generated.
1315  * @status: value for the STATUS field of the SRP_RSP information unit.
1316  *
1317  * Returns the size in bytes of the SRP_RSP response.
1318  *
1319  * An SRP_RSP response contains a SCSI status or service response. See also
1320  * section 6.9 in the SRP r16a document for the format of an SRP_RSP
1321  * response. See also SPC-2 for more information about sense data.
1322  */
1323 static int srpt_build_cmd_rsp(struct srpt_rdma_ch *ch,
1324 			      struct srpt_send_ioctx *ioctx, u64 tag,
1325 			      int status)
1326 {
1327 	struct srp_rsp *srp_rsp;
1328 	const u8 *sense_data;
1329 	int sense_data_len, max_sense_len;
1330 
1331 	/*
1332 	 * The lowest bit of all SAM-3 status codes is zero (see also
1333 	 * paragraph 5.3 in SAM-3).
1334 	 */
1335 	WARN_ON(status & 1);
1336 
1337 	srp_rsp = ioctx->ioctx.buf;
1338 	BUG_ON(!srp_rsp);
1339 
1340 	sense_data = ioctx->sense_data;
1341 	sense_data_len = ioctx->cmd.scsi_sense_length;
1342 	WARN_ON(sense_data_len > sizeof(ioctx->sense_data));
1343 
1344 	memset(srp_rsp, 0, sizeof(*srp_rsp));
1345 	srp_rsp->opcode = SRP_RSP;
1346 	srp_rsp->req_lim_delta =
1347 		cpu_to_be32(1 + atomic_xchg(&ch->req_lim_delta, 0));
1348 	srp_rsp->tag = tag;
1349 	srp_rsp->status = status;
1350 
1351 	if (sense_data_len) {
1352 		BUILD_BUG_ON(MIN_MAX_RSP_SIZE <= sizeof(*srp_rsp));
1353 		max_sense_len = ch->max_ti_iu_len - sizeof(*srp_rsp);
1354 		if (sense_data_len > max_sense_len) {
1355 			pr_warn("truncated sense data from %d to %d"
1356 				" bytes\n", sense_data_len, max_sense_len);
1357 			sense_data_len = max_sense_len;
1358 		}
1359 
1360 		srp_rsp->flags |= SRP_RSP_FLAG_SNSVALID;
1361 		srp_rsp->sense_data_len = cpu_to_be32(sense_data_len);
1362 		memcpy(srp_rsp + 1, sense_data, sense_data_len);
1363 	}
1364 
1365 	return sizeof(*srp_rsp) + sense_data_len;
1366 }
1367 
1368 /**
1369  * srpt_build_tskmgmt_rsp - build a task management response
1370  * @ch:       RDMA channel through which the request has been received.
1371  * @ioctx:    I/O context in which the SRP_RSP response will be built.
1372  * @rsp_code: RSP_CODE that will be stored in the response.
1373  * @tag:      Tag of the request for which this response is being generated.
1374  *
1375  * Returns the size in bytes of the SRP_RSP response.
1376  *
1377  * An SRP_RSP response contains a SCSI status or service response. See also
1378  * section 6.9 in the SRP r16a document for the format of an SRP_RSP
1379  * response.
1380  */
1381 static int srpt_build_tskmgmt_rsp(struct srpt_rdma_ch *ch,
1382 				  struct srpt_send_ioctx *ioctx,
1383 				  u8 rsp_code, u64 tag)
1384 {
1385 	struct srp_rsp *srp_rsp;
1386 	int resp_data_len;
1387 	int resp_len;
1388 
1389 	resp_data_len = 4;
1390 	resp_len = sizeof(*srp_rsp) + resp_data_len;
1391 
1392 	srp_rsp = ioctx->ioctx.buf;
1393 	BUG_ON(!srp_rsp);
1394 	memset(srp_rsp, 0, sizeof(*srp_rsp));
1395 
1396 	srp_rsp->opcode = SRP_RSP;
1397 	srp_rsp->req_lim_delta =
1398 		cpu_to_be32(1 + atomic_xchg(&ch->req_lim_delta, 0));
1399 	srp_rsp->tag = tag;
1400 
1401 	srp_rsp->flags |= SRP_RSP_FLAG_RSPVALID;
1402 	srp_rsp->resp_data_len = cpu_to_be32(resp_data_len);
1403 	srp_rsp->data[3] = rsp_code;
1404 
1405 	return resp_len;
1406 }
1407 
1408 static int srpt_check_stop_free(struct se_cmd *cmd)
1409 {
1410 	struct srpt_send_ioctx *ioctx = container_of(cmd,
1411 				struct srpt_send_ioctx, cmd);
1412 
1413 	return target_put_sess_cmd(&ioctx->cmd);
1414 }
1415 
1416 /**
1417  * srpt_handle_cmd - process a SRP_CMD information unit
1418  * @ch: SRPT RDMA channel.
1419  * @recv_ioctx: Receive I/O context.
1420  * @send_ioctx: Send I/O context.
1421  */
1422 static void srpt_handle_cmd(struct srpt_rdma_ch *ch,
1423 			    struct srpt_recv_ioctx *recv_ioctx,
1424 			    struct srpt_send_ioctx *send_ioctx)
1425 {
1426 	struct se_cmd *cmd;
1427 	struct srp_cmd *srp_cmd;
1428 	struct scatterlist *sg = NULL;
1429 	unsigned sg_cnt = 0;
1430 	u64 data_len;
1431 	enum dma_data_direction dir;
1432 	int rc;
1433 
1434 	BUG_ON(!send_ioctx);
1435 
1436 	srp_cmd = recv_ioctx->ioctx.buf;
1437 	cmd = &send_ioctx->cmd;
1438 	cmd->tag = srp_cmd->tag;
1439 
1440 	switch (srp_cmd->task_attr) {
1441 	case SRP_CMD_SIMPLE_Q:
1442 		cmd->sam_task_attr = TCM_SIMPLE_TAG;
1443 		break;
1444 	case SRP_CMD_ORDERED_Q:
1445 	default:
1446 		cmd->sam_task_attr = TCM_ORDERED_TAG;
1447 		break;
1448 	case SRP_CMD_HEAD_OF_Q:
1449 		cmd->sam_task_attr = TCM_HEAD_TAG;
1450 		break;
1451 	case SRP_CMD_ACA:
1452 		cmd->sam_task_attr = TCM_ACA_TAG;
1453 		break;
1454 	}
1455 
1456 	rc = srpt_get_desc_tbl(send_ioctx, srp_cmd, &dir, &sg, &sg_cnt,
1457 			&data_len);
1458 	if (rc) {
1459 		if (rc != -EAGAIN) {
1460 			pr_err("0x%llx: parsing SRP descriptor table failed.\n",
1461 			       srp_cmd->tag);
1462 		}
1463 		goto release_ioctx;
1464 	}
1465 
1466 	rc = target_submit_cmd_map_sgls(cmd, ch->sess, srp_cmd->cdb,
1467 			       &send_ioctx->sense_data[0],
1468 			       scsilun_to_int(&srp_cmd->lun), data_len,
1469 			       TCM_SIMPLE_TAG, dir, TARGET_SCF_ACK_KREF,
1470 			       sg, sg_cnt, NULL, 0, NULL, 0);
1471 	if (rc != 0) {
1472 		pr_debug("target_submit_cmd() returned %d for tag %#llx\n", rc,
1473 			 srp_cmd->tag);
1474 		goto release_ioctx;
1475 	}
1476 	return;
1477 
1478 release_ioctx:
1479 	send_ioctx->state = SRPT_STATE_DONE;
1480 	srpt_release_cmd(cmd);
1481 }
1482 
1483 static int srp_tmr_to_tcm(int fn)
1484 {
1485 	switch (fn) {
1486 	case SRP_TSK_ABORT_TASK:
1487 		return TMR_ABORT_TASK;
1488 	case SRP_TSK_ABORT_TASK_SET:
1489 		return TMR_ABORT_TASK_SET;
1490 	case SRP_TSK_CLEAR_TASK_SET:
1491 		return TMR_CLEAR_TASK_SET;
1492 	case SRP_TSK_LUN_RESET:
1493 		return TMR_LUN_RESET;
1494 	case SRP_TSK_CLEAR_ACA:
1495 		return TMR_CLEAR_ACA;
1496 	default:
1497 		return -1;
1498 	}
1499 }
1500 
1501 /**
1502  * srpt_handle_tsk_mgmt - process a SRP_TSK_MGMT information unit
1503  * @ch: SRPT RDMA channel.
1504  * @recv_ioctx: Receive I/O context.
1505  * @send_ioctx: Send I/O context.
1506  *
1507  * Returns 0 if and only if the request will be processed by the target core.
1508  *
1509  * For more information about SRP_TSK_MGMT information units, see also section
1510  * 6.7 in the SRP r16a document.
1511  */
1512 static void srpt_handle_tsk_mgmt(struct srpt_rdma_ch *ch,
1513 				 struct srpt_recv_ioctx *recv_ioctx,
1514 				 struct srpt_send_ioctx *send_ioctx)
1515 {
1516 	struct srp_tsk_mgmt *srp_tsk;
1517 	struct se_cmd *cmd;
1518 	struct se_session *sess = ch->sess;
1519 	int tcm_tmr;
1520 	int rc;
1521 
1522 	BUG_ON(!send_ioctx);
1523 
1524 	srp_tsk = recv_ioctx->ioctx.buf;
1525 	cmd = &send_ioctx->cmd;
1526 
1527 	pr_debug("recv tsk_mgmt fn %d for task_tag %lld and cmd tag %lld ch %p sess %p\n",
1528 		 srp_tsk->tsk_mgmt_func, srp_tsk->task_tag, srp_tsk->tag, ch,
1529 		 ch->sess);
1530 
1531 	srpt_set_cmd_state(send_ioctx, SRPT_STATE_MGMT);
1532 	send_ioctx->cmd.tag = srp_tsk->tag;
1533 	tcm_tmr = srp_tmr_to_tcm(srp_tsk->tsk_mgmt_func);
1534 	rc = target_submit_tmr(&send_ioctx->cmd, sess, NULL,
1535 			       scsilun_to_int(&srp_tsk->lun), srp_tsk, tcm_tmr,
1536 			       GFP_KERNEL, srp_tsk->task_tag,
1537 			       TARGET_SCF_ACK_KREF);
1538 	if (rc != 0) {
1539 		send_ioctx->cmd.se_tmr_req->response = TMR_FUNCTION_REJECTED;
1540 		goto fail;
1541 	}
1542 	return;
1543 fail:
1544 	transport_send_check_condition_and_sense(cmd, 0, 0); // XXX:
1545 }
1546 
1547 /**
1548  * srpt_handle_new_iu - process a newly received information unit
1549  * @ch:    RDMA channel through which the information unit has been received.
1550  * @recv_ioctx: Receive I/O context associated with the information unit.
1551  */
1552 static bool
1553 srpt_handle_new_iu(struct srpt_rdma_ch *ch, struct srpt_recv_ioctx *recv_ioctx)
1554 {
1555 	struct srpt_send_ioctx *send_ioctx = NULL;
1556 	struct srp_cmd *srp_cmd;
1557 	bool res = false;
1558 	u8 opcode;
1559 
1560 	BUG_ON(!ch);
1561 	BUG_ON(!recv_ioctx);
1562 
1563 	if (unlikely(ch->state == CH_CONNECTING))
1564 		goto push;
1565 
1566 	ib_dma_sync_single_for_cpu(ch->sport->sdev->device,
1567 				   recv_ioctx->ioctx.dma, srp_max_req_size,
1568 				   DMA_FROM_DEVICE);
1569 
1570 	srp_cmd = recv_ioctx->ioctx.buf;
1571 	opcode = srp_cmd->opcode;
1572 	if (opcode == SRP_CMD || opcode == SRP_TSK_MGMT) {
1573 		send_ioctx = srpt_get_send_ioctx(ch);
1574 		if (unlikely(!send_ioctx))
1575 			goto push;
1576 	}
1577 
1578 	if (!list_empty(&recv_ioctx->wait_list)) {
1579 		WARN_ON_ONCE(!ch->processing_wait_list);
1580 		list_del_init(&recv_ioctx->wait_list);
1581 	}
1582 
1583 	switch (opcode) {
1584 	case SRP_CMD:
1585 		srpt_handle_cmd(ch, recv_ioctx, send_ioctx);
1586 		break;
1587 	case SRP_TSK_MGMT:
1588 		srpt_handle_tsk_mgmt(ch, recv_ioctx, send_ioctx);
1589 		break;
1590 	case SRP_I_LOGOUT:
1591 		pr_err("Not yet implemented: SRP_I_LOGOUT\n");
1592 		break;
1593 	case SRP_CRED_RSP:
1594 		pr_debug("received SRP_CRED_RSP\n");
1595 		break;
1596 	case SRP_AER_RSP:
1597 		pr_debug("received SRP_AER_RSP\n");
1598 		break;
1599 	case SRP_RSP:
1600 		pr_err("Received SRP_RSP\n");
1601 		break;
1602 	default:
1603 		pr_err("received IU with unknown opcode 0x%x\n", opcode);
1604 		break;
1605 	}
1606 
1607 	srpt_post_recv(ch->sport->sdev, ch, recv_ioctx);
1608 	res = true;
1609 
1610 out:
1611 	return res;
1612 
1613 push:
1614 	if (list_empty(&recv_ioctx->wait_list)) {
1615 		WARN_ON_ONCE(ch->processing_wait_list);
1616 		list_add_tail(&recv_ioctx->wait_list, &ch->cmd_wait_list);
1617 	}
1618 	goto out;
1619 }
1620 
1621 static void srpt_recv_done(struct ib_cq *cq, struct ib_wc *wc)
1622 {
1623 	struct srpt_rdma_ch *ch = cq->cq_context;
1624 	struct srpt_recv_ioctx *ioctx =
1625 		container_of(wc->wr_cqe, struct srpt_recv_ioctx, ioctx.cqe);
1626 
1627 	if (wc->status == IB_WC_SUCCESS) {
1628 		int req_lim;
1629 
1630 		req_lim = atomic_dec_return(&ch->req_lim);
1631 		if (unlikely(req_lim < 0))
1632 			pr_err("req_lim = %d < 0\n", req_lim);
1633 		srpt_handle_new_iu(ch, ioctx);
1634 	} else {
1635 		pr_info_ratelimited("receiving failed for ioctx %p with status %d\n",
1636 				    ioctx, wc->status);
1637 	}
1638 }
1639 
1640 /*
1641  * This function must be called from the context in which RDMA completions are
1642  * processed because it accesses the wait list without protection against
1643  * access from other threads.
1644  */
1645 static void srpt_process_wait_list(struct srpt_rdma_ch *ch)
1646 {
1647 	struct srpt_recv_ioctx *recv_ioctx, *tmp;
1648 
1649 	WARN_ON_ONCE(ch->state == CH_CONNECTING);
1650 
1651 	if (list_empty(&ch->cmd_wait_list))
1652 		return;
1653 
1654 	WARN_ON_ONCE(ch->processing_wait_list);
1655 	ch->processing_wait_list = true;
1656 	list_for_each_entry_safe(recv_ioctx, tmp, &ch->cmd_wait_list,
1657 				 wait_list) {
1658 		if (!srpt_handle_new_iu(ch, recv_ioctx))
1659 			break;
1660 	}
1661 	ch->processing_wait_list = false;
1662 }
1663 
1664 /**
1665  * srpt_send_done - send completion callback
1666  * @cq: Completion queue.
1667  * @wc: Work completion.
1668  *
1669  * Note: Although this has not yet been observed during tests, at least in
1670  * theory it is possible that the srpt_get_send_ioctx() call invoked by
1671  * srpt_handle_new_iu() fails. This is possible because the req_lim_delta
1672  * value in each response is set to one, and it is possible that this response
1673  * makes the initiator send a new request before the send completion for that
1674  * response has been processed. This could e.g. happen if the call to
1675  * srpt_put_send_iotcx() is delayed because of a higher priority interrupt or
1676  * if IB retransmission causes generation of the send completion to be
1677  * delayed. Incoming information units for which srpt_get_send_ioctx() fails
1678  * are queued on cmd_wait_list. The code below processes these delayed
1679  * requests one at a time.
1680  */
1681 static void srpt_send_done(struct ib_cq *cq, struct ib_wc *wc)
1682 {
1683 	struct srpt_rdma_ch *ch = cq->cq_context;
1684 	struct srpt_send_ioctx *ioctx =
1685 		container_of(wc->wr_cqe, struct srpt_send_ioctx, ioctx.cqe);
1686 	enum srpt_command_state state;
1687 
1688 	state = srpt_set_cmd_state(ioctx, SRPT_STATE_DONE);
1689 
1690 	WARN_ON(state != SRPT_STATE_CMD_RSP_SENT &&
1691 		state != SRPT_STATE_MGMT_RSP_SENT);
1692 
1693 	atomic_add(1 + ioctx->n_rdma, &ch->sq_wr_avail);
1694 
1695 	if (wc->status != IB_WC_SUCCESS)
1696 		pr_info("sending response for ioctx 0x%p failed"
1697 			" with status %d\n", ioctx, wc->status);
1698 
1699 	if (state != SRPT_STATE_DONE) {
1700 		transport_generic_free_cmd(&ioctx->cmd, 0);
1701 	} else {
1702 		pr_err("IB completion has been received too late for"
1703 		       " wr_id = %u.\n", ioctx->ioctx.index);
1704 	}
1705 
1706 	srpt_process_wait_list(ch);
1707 }
1708 
1709 /**
1710  * srpt_create_ch_ib - create receive and send completion queues
1711  * @ch: SRPT RDMA channel.
1712  */
1713 static int srpt_create_ch_ib(struct srpt_rdma_ch *ch)
1714 {
1715 	struct ib_qp_init_attr *qp_init;
1716 	struct srpt_port *sport = ch->sport;
1717 	struct srpt_device *sdev = sport->sdev;
1718 	const struct ib_device_attr *attrs = &sdev->device->attrs;
1719 	int sq_size = sport->port_attrib.srp_sq_size;
1720 	int i, ret;
1721 
1722 	WARN_ON(ch->rq_size < 1);
1723 
1724 	ret = -ENOMEM;
1725 	qp_init = kzalloc(sizeof(*qp_init), GFP_KERNEL);
1726 	if (!qp_init)
1727 		goto out;
1728 
1729 retry:
1730 	ch->cq = ib_alloc_cq(sdev->device, ch, ch->rq_size + sq_size,
1731 			0 /* XXX: spread CQs */, IB_POLL_WORKQUEUE);
1732 	if (IS_ERR(ch->cq)) {
1733 		ret = PTR_ERR(ch->cq);
1734 		pr_err("failed to create CQ cqe= %d ret= %d\n",
1735 		       ch->rq_size + sq_size, ret);
1736 		goto out;
1737 	}
1738 
1739 	qp_init->qp_context = (void *)ch;
1740 	qp_init->event_handler
1741 		= (void(*)(struct ib_event *, void*))srpt_qp_event;
1742 	qp_init->send_cq = ch->cq;
1743 	qp_init->recv_cq = ch->cq;
1744 	qp_init->sq_sig_type = IB_SIGNAL_REQ_WR;
1745 	qp_init->qp_type = IB_QPT_RC;
1746 	/*
1747 	 * We divide up our send queue size into half SEND WRs to send the
1748 	 * completions, and half R/W contexts to actually do the RDMA
1749 	 * READ/WRITE transfers.  Note that we need to allocate CQ slots for
1750 	 * both both, as RDMA contexts will also post completions for the
1751 	 * RDMA READ case.
1752 	 */
1753 	qp_init->cap.max_send_wr = min(sq_size / 2, attrs->max_qp_wr);
1754 	qp_init->cap.max_rdma_ctxs = sq_size / 2;
1755 	qp_init->cap.max_send_sge = min(attrs->max_send_sge,
1756 					SRPT_MAX_SG_PER_WQE);
1757 	qp_init->port_num = ch->sport->port;
1758 	if (sdev->use_srq) {
1759 		qp_init->srq = sdev->srq;
1760 	} else {
1761 		qp_init->cap.max_recv_wr = ch->rq_size;
1762 		qp_init->cap.max_recv_sge = min(attrs->max_recv_sge,
1763 						SRPT_MAX_SG_PER_WQE);
1764 	}
1765 
1766 	if (ch->using_rdma_cm) {
1767 		ret = rdma_create_qp(ch->rdma_cm.cm_id, sdev->pd, qp_init);
1768 		ch->qp = ch->rdma_cm.cm_id->qp;
1769 	} else {
1770 		ch->qp = ib_create_qp(sdev->pd, qp_init);
1771 		if (!IS_ERR(ch->qp)) {
1772 			ret = srpt_init_ch_qp(ch, ch->qp);
1773 			if (ret)
1774 				ib_destroy_qp(ch->qp);
1775 		} else {
1776 			ret = PTR_ERR(ch->qp);
1777 		}
1778 	}
1779 	if (ret) {
1780 		bool retry = sq_size > MIN_SRPT_SQ_SIZE;
1781 
1782 		if (retry) {
1783 			pr_debug("failed to create queue pair with sq_size = %d (%d) - retrying\n",
1784 				 sq_size, ret);
1785 			ib_free_cq(ch->cq);
1786 			sq_size = max(sq_size / 2, MIN_SRPT_SQ_SIZE);
1787 			goto retry;
1788 		} else {
1789 			pr_err("failed to create queue pair with sq_size = %d (%d)\n",
1790 			       sq_size, ret);
1791 			goto err_destroy_cq;
1792 		}
1793 	}
1794 
1795 	atomic_set(&ch->sq_wr_avail, qp_init->cap.max_send_wr);
1796 
1797 	pr_debug("%s: max_cqe= %d max_sge= %d sq_size = %d ch= %p\n",
1798 		 __func__, ch->cq->cqe, qp_init->cap.max_send_sge,
1799 		 qp_init->cap.max_send_wr, ch);
1800 
1801 	if (!sdev->use_srq)
1802 		for (i = 0; i < ch->rq_size; i++)
1803 			srpt_post_recv(sdev, ch, ch->ioctx_recv_ring[i]);
1804 
1805 out:
1806 	kfree(qp_init);
1807 	return ret;
1808 
1809 err_destroy_cq:
1810 	ch->qp = NULL;
1811 	ib_free_cq(ch->cq);
1812 	goto out;
1813 }
1814 
1815 static void srpt_destroy_ch_ib(struct srpt_rdma_ch *ch)
1816 {
1817 	ib_destroy_qp(ch->qp);
1818 	ib_free_cq(ch->cq);
1819 }
1820 
1821 /**
1822  * srpt_close_ch - close a RDMA channel
1823  * @ch: SRPT RDMA channel.
1824  *
1825  * Make sure all resources associated with the channel will be deallocated at
1826  * an appropriate time.
1827  *
1828  * Returns true if and only if the channel state has been modified into
1829  * CH_DRAINING.
1830  */
1831 static bool srpt_close_ch(struct srpt_rdma_ch *ch)
1832 {
1833 	int ret;
1834 
1835 	if (!srpt_set_ch_state(ch, CH_DRAINING)) {
1836 		pr_debug("%s: already closed\n", ch->sess_name);
1837 		return false;
1838 	}
1839 
1840 	kref_get(&ch->kref);
1841 
1842 	ret = srpt_ch_qp_err(ch);
1843 	if (ret < 0)
1844 		pr_err("%s-%d: changing queue pair into error state failed: %d\n",
1845 		       ch->sess_name, ch->qp->qp_num, ret);
1846 
1847 	ret = srpt_zerolength_write(ch);
1848 	if (ret < 0) {
1849 		pr_err("%s-%d: queuing zero-length write failed: %d\n",
1850 		       ch->sess_name, ch->qp->qp_num, ret);
1851 		if (srpt_set_ch_state(ch, CH_DISCONNECTED))
1852 			schedule_work(&ch->release_work);
1853 		else
1854 			WARN_ON_ONCE(true);
1855 	}
1856 
1857 	kref_put(&ch->kref, srpt_free_ch);
1858 
1859 	return true;
1860 }
1861 
1862 /*
1863  * Change the channel state into CH_DISCONNECTING. If a channel has not yet
1864  * reached the connected state, close it. If a channel is in the connected
1865  * state, send a DREQ. If a DREQ has been received, send a DREP. Note: it is
1866  * the responsibility of the caller to ensure that this function is not
1867  * invoked concurrently with the code that accepts a connection. This means
1868  * that this function must either be invoked from inside a CM callback
1869  * function or that it must be invoked with the srpt_port.mutex held.
1870  */
1871 static int srpt_disconnect_ch(struct srpt_rdma_ch *ch)
1872 {
1873 	int ret;
1874 
1875 	if (!srpt_set_ch_state(ch, CH_DISCONNECTING))
1876 		return -ENOTCONN;
1877 
1878 	if (ch->using_rdma_cm) {
1879 		ret = rdma_disconnect(ch->rdma_cm.cm_id);
1880 	} else {
1881 		ret = ib_send_cm_dreq(ch->ib_cm.cm_id, NULL, 0);
1882 		if (ret < 0)
1883 			ret = ib_send_cm_drep(ch->ib_cm.cm_id, NULL, 0);
1884 	}
1885 
1886 	if (ret < 0 && srpt_close_ch(ch))
1887 		ret = 0;
1888 
1889 	return ret;
1890 }
1891 
1892 static bool srpt_ch_closed(struct srpt_port *sport, struct srpt_rdma_ch *ch)
1893 {
1894 	struct srpt_nexus *nexus;
1895 	struct srpt_rdma_ch *ch2;
1896 	bool res = true;
1897 
1898 	rcu_read_lock();
1899 	list_for_each_entry(nexus, &sport->nexus_list, entry) {
1900 		list_for_each_entry(ch2, &nexus->ch_list, list) {
1901 			if (ch2 == ch) {
1902 				res = false;
1903 				goto done;
1904 			}
1905 		}
1906 	}
1907 done:
1908 	rcu_read_unlock();
1909 
1910 	return res;
1911 }
1912 
1913 /* Send DREQ and wait for DREP. */
1914 static void srpt_disconnect_ch_sync(struct srpt_rdma_ch *ch)
1915 {
1916 	struct srpt_port *sport = ch->sport;
1917 
1918 	pr_debug("ch %s-%d state %d\n", ch->sess_name, ch->qp->qp_num,
1919 		 ch->state);
1920 
1921 	mutex_lock(&sport->mutex);
1922 	srpt_disconnect_ch(ch);
1923 	mutex_unlock(&sport->mutex);
1924 
1925 	while (wait_event_timeout(sport->ch_releaseQ, srpt_ch_closed(sport, ch),
1926 				  5 * HZ) == 0)
1927 		pr_info("%s(%s-%d state %d): still waiting ...\n", __func__,
1928 			ch->sess_name, ch->qp->qp_num, ch->state);
1929 
1930 }
1931 
1932 static void __srpt_close_all_ch(struct srpt_port *sport)
1933 {
1934 	struct srpt_nexus *nexus;
1935 	struct srpt_rdma_ch *ch;
1936 
1937 	lockdep_assert_held(&sport->mutex);
1938 
1939 	list_for_each_entry(nexus, &sport->nexus_list, entry) {
1940 		list_for_each_entry(ch, &nexus->ch_list, list) {
1941 			if (srpt_disconnect_ch(ch) >= 0)
1942 				pr_info("Closing channel %s because target %s_%d has been disabled\n",
1943 					ch->sess_name,
1944 					sport->sdev->device->name, sport->port);
1945 			srpt_close_ch(ch);
1946 		}
1947 	}
1948 }
1949 
1950 /*
1951  * Look up (i_port_id, t_port_id) in sport->nexus_list. Create an entry if
1952  * it does not yet exist.
1953  */
1954 static struct srpt_nexus *srpt_get_nexus(struct srpt_port *sport,
1955 					 const u8 i_port_id[16],
1956 					 const u8 t_port_id[16])
1957 {
1958 	struct srpt_nexus *nexus = NULL, *tmp_nexus = NULL, *n;
1959 
1960 	for (;;) {
1961 		mutex_lock(&sport->mutex);
1962 		list_for_each_entry(n, &sport->nexus_list, entry) {
1963 			if (memcmp(n->i_port_id, i_port_id, 16) == 0 &&
1964 			    memcmp(n->t_port_id, t_port_id, 16) == 0) {
1965 				nexus = n;
1966 				break;
1967 			}
1968 		}
1969 		if (!nexus && tmp_nexus) {
1970 			list_add_tail_rcu(&tmp_nexus->entry,
1971 					  &sport->nexus_list);
1972 			swap(nexus, tmp_nexus);
1973 		}
1974 		mutex_unlock(&sport->mutex);
1975 
1976 		if (nexus)
1977 			break;
1978 		tmp_nexus = kzalloc(sizeof(*nexus), GFP_KERNEL);
1979 		if (!tmp_nexus) {
1980 			nexus = ERR_PTR(-ENOMEM);
1981 			break;
1982 		}
1983 		INIT_LIST_HEAD(&tmp_nexus->ch_list);
1984 		memcpy(tmp_nexus->i_port_id, i_port_id, 16);
1985 		memcpy(tmp_nexus->t_port_id, t_port_id, 16);
1986 	}
1987 
1988 	kfree(tmp_nexus);
1989 
1990 	return nexus;
1991 }
1992 
1993 static void srpt_set_enabled(struct srpt_port *sport, bool enabled)
1994 	__must_hold(&sport->mutex)
1995 {
1996 	lockdep_assert_held(&sport->mutex);
1997 
1998 	if (sport->enabled == enabled)
1999 		return;
2000 	sport->enabled = enabled;
2001 	if (!enabled)
2002 		__srpt_close_all_ch(sport);
2003 }
2004 
2005 static void srpt_free_ch(struct kref *kref)
2006 {
2007 	struct srpt_rdma_ch *ch = container_of(kref, struct srpt_rdma_ch, kref);
2008 
2009 	kfree_rcu(ch, rcu);
2010 }
2011 
2012 static void srpt_release_channel_work(struct work_struct *w)
2013 {
2014 	struct srpt_rdma_ch *ch;
2015 	struct srpt_device *sdev;
2016 	struct srpt_port *sport;
2017 	struct se_session *se_sess;
2018 
2019 	ch = container_of(w, struct srpt_rdma_ch, release_work);
2020 	pr_debug("%s-%d\n", ch->sess_name, ch->qp->qp_num);
2021 
2022 	sdev = ch->sport->sdev;
2023 	BUG_ON(!sdev);
2024 
2025 	se_sess = ch->sess;
2026 	BUG_ON(!se_sess);
2027 
2028 	target_sess_cmd_list_set_waiting(se_sess);
2029 	target_wait_for_sess_cmds(se_sess);
2030 
2031 	target_remove_session(se_sess);
2032 	ch->sess = NULL;
2033 
2034 	if (ch->using_rdma_cm)
2035 		rdma_destroy_id(ch->rdma_cm.cm_id);
2036 	else
2037 		ib_destroy_cm_id(ch->ib_cm.cm_id);
2038 
2039 	srpt_destroy_ch_ib(ch);
2040 
2041 	srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_ring,
2042 			     ch->sport->sdev, ch->rq_size,
2043 			     ch->max_rsp_size, DMA_TO_DEVICE);
2044 
2045 	srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_recv_ring,
2046 			     sdev, ch->rq_size,
2047 			     srp_max_req_size, DMA_FROM_DEVICE);
2048 
2049 	sport = ch->sport;
2050 	mutex_lock(&sport->mutex);
2051 	list_del_rcu(&ch->list);
2052 	mutex_unlock(&sport->mutex);
2053 
2054 	wake_up(&sport->ch_releaseQ);
2055 
2056 	kref_put(&ch->kref, srpt_free_ch);
2057 }
2058 
2059 /**
2060  * srpt_cm_req_recv - process the event IB_CM_REQ_RECEIVED
2061  * @sdev: HCA through which the login request was received.
2062  * @ib_cm_id: IB/CM connection identifier in case of IB/CM.
2063  * @rdma_cm_id: RDMA/CM connection identifier in case of RDMA/CM.
2064  * @port_num: Port through which the REQ message was received.
2065  * @pkey: P_Key of the incoming connection.
2066  * @req: SRP login request.
2067  * @src_addr: GID (IB/CM) or IP address (RDMA/CM) of the port that submitted
2068  * the login request.
2069  *
2070  * Ownership of the cm_id is transferred to the target session if this
2071  * function returns zero. Otherwise the caller remains the owner of cm_id.
2072  */
2073 static int srpt_cm_req_recv(struct srpt_device *const sdev,
2074 			    struct ib_cm_id *ib_cm_id,
2075 			    struct rdma_cm_id *rdma_cm_id,
2076 			    u8 port_num, __be16 pkey,
2077 			    const struct srp_login_req *req,
2078 			    const char *src_addr)
2079 {
2080 	struct srpt_port *sport = &sdev->port[port_num - 1];
2081 	struct srpt_nexus *nexus;
2082 	struct srp_login_rsp *rsp = NULL;
2083 	struct srp_login_rej *rej = NULL;
2084 	union {
2085 		struct rdma_conn_param rdma_cm;
2086 		struct ib_cm_rep_param ib_cm;
2087 	} *rep_param = NULL;
2088 	struct srpt_rdma_ch *ch = NULL;
2089 	char i_port_id[36];
2090 	u32 it_iu_len;
2091 	int i, ret;
2092 
2093 	WARN_ON_ONCE(irqs_disabled());
2094 
2095 	if (WARN_ON(!sdev || !req))
2096 		return -EINVAL;
2097 
2098 	it_iu_len = be32_to_cpu(req->req_it_iu_len);
2099 
2100 	pr_info("Received SRP_LOGIN_REQ with i_port_id %pI6, t_port_id %pI6 and it_iu_len %d on port %d (guid=%pI6); pkey %#04x\n",
2101 		req->initiator_port_id, req->target_port_id, it_iu_len,
2102 		port_num, &sport->gid, be16_to_cpu(pkey));
2103 
2104 	nexus = srpt_get_nexus(sport, req->initiator_port_id,
2105 			       req->target_port_id);
2106 	if (IS_ERR(nexus)) {
2107 		ret = PTR_ERR(nexus);
2108 		goto out;
2109 	}
2110 
2111 	ret = -ENOMEM;
2112 	rsp = kzalloc(sizeof(*rsp), GFP_KERNEL);
2113 	rej = kzalloc(sizeof(*rej), GFP_KERNEL);
2114 	rep_param = kzalloc(sizeof(*rep_param), GFP_KERNEL);
2115 	if (!rsp || !rej || !rep_param)
2116 		goto out;
2117 
2118 	ret = -EINVAL;
2119 	if (it_iu_len > srp_max_req_size || it_iu_len < 64) {
2120 		rej->reason = cpu_to_be32(
2121 				SRP_LOGIN_REJ_REQ_IT_IU_LENGTH_TOO_LARGE);
2122 		pr_err("rejected SRP_LOGIN_REQ because its length (%d bytes) is out of range (%d .. %d)\n",
2123 		       it_iu_len, 64, srp_max_req_size);
2124 		goto reject;
2125 	}
2126 
2127 	if (!sport->enabled) {
2128 		rej->reason = cpu_to_be32(SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
2129 		pr_info("rejected SRP_LOGIN_REQ because target port %s_%d has not yet been enabled\n",
2130 			sport->sdev->device->name, port_num);
2131 		goto reject;
2132 	}
2133 
2134 	if (*(__be64 *)req->target_port_id != cpu_to_be64(srpt_service_guid)
2135 	    || *(__be64 *)(req->target_port_id + 8) !=
2136 	       cpu_to_be64(srpt_service_guid)) {
2137 		rej->reason = cpu_to_be32(
2138 				SRP_LOGIN_REJ_UNABLE_ASSOCIATE_CHANNEL);
2139 		pr_err("rejected SRP_LOGIN_REQ because it has an invalid target port identifier.\n");
2140 		goto reject;
2141 	}
2142 
2143 	ret = -ENOMEM;
2144 	ch = kzalloc(sizeof(*ch), GFP_KERNEL);
2145 	if (!ch) {
2146 		rej->reason = cpu_to_be32(SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
2147 		pr_err("rejected SRP_LOGIN_REQ because out of memory.\n");
2148 		goto reject;
2149 	}
2150 
2151 	kref_init(&ch->kref);
2152 	ch->pkey = be16_to_cpu(pkey);
2153 	ch->nexus = nexus;
2154 	ch->zw_cqe.done = srpt_zerolength_write_done;
2155 	INIT_WORK(&ch->release_work, srpt_release_channel_work);
2156 	ch->sport = sport;
2157 	if (ib_cm_id) {
2158 		ch->ib_cm.cm_id = ib_cm_id;
2159 		ib_cm_id->context = ch;
2160 	} else {
2161 		ch->using_rdma_cm = true;
2162 		ch->rdma_cm.cm_id = rdma_cm_id;
2163 		rdma_cm_id->context = ch;
2164 	}
2165 	/*
2166 	 * ch->rq_size should be at least as large as the initiator queue
2167 	 * depth to avoid that the initiator driver has to report QUEUE_FULL
2168 	 * to the SCSI mid-layer.
2169 	 */
2170 	ch->rq_size = min(MAX_SRPT_RQ_SIZE, sdev->device->attrs.max_qp_wr);
2171 	spin_lock_init(&ch->spinlock);
2172 	ch->state = CH_CONNECTING;
2173 	INIT_LIST_HEAD(&ch->cmd_wait_list);
2174 	ch->max_rsp_size = ch->sport->port_attrib.srp_max_rsp_size;
2175 
2176 	ch->ioctx_ring = (struct srpt_send_ioctx **)
2177 		srpt_alloc_ioctx_ring(ch->sport->sdev, ch->rq_size,
2178 				      sizeof(*ch->ioctx_ring[0]),
2179 				      ch->max_rsp_size, DMA_TO_DEVICE);
2180 	if (!ch->ioctx_ring) {
2181 		pr_err("rejected SRP_LOGIN_REQ because creating a new QP SQ ring failed.\n");
2182 		rej->reason = cpu_to_be32(SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
2183 		goto free_ch;
2184 	}
2185 
2186 	INIT_LIST_HEAD(&ch->free_list);
2187 	for (i = 0; i < ch->rq_size; i++) {
2188 		ch->ioctx_ring[i]->ch = ch;
2189 		list_add_tail(&ch->ioctx_ring[i]->free_list, &ch->free_list);
2190 	}
2191 	if (!sdev->use_srq) {
2192 		ch->ioctx_recv_ring = (struct srpt_recv_ioctx **)
2193 			srpt_alloc_ioctx_ring(ch->sport->sdev, ch->rq_size,
2194 					      sizeof(*ch->ioctx_recv_ring[0]),
2195 					      srp_max_req_size,
2196 					      DMA_FROM_DEVICE);
2197 		if (!ch->ioctx_recv_ring) {
2198 			pr_err("rejected SRP_LOGIN_REQ because creating a new QP RQ ring failed.\n");
2199 			rej->reason =
2200 			    cpu_to_be32(SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
2201 			goto free_ring;
2202 		}
2203 		for (i = 0; i < ch->rq_size; i++)
2204 			INIT_LIST_HEAD(&ch->ioctx_recv_ring[i]->wait_list);
2205 	}
2206 
2207 	ret = srpt_create_ch_ib(ch);
2208 	if (ret) {
2209 		rej->reason = cpu_to_be32(SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
2210 		pr_err("rejected SRP_LOGIN_REQ because creating a new RDMA channel failed.\n");
2211 		goto free_recv_ring;
2212 	}
2213 
2214 	strlcpy(ch->sess_name, src_addr, sizeof(ch->sess_name));
2215 	snprintf(i_port_id, sizeof(i_port_id), "0x%016llx%016llx",
2216 			be64_to_cpu(*(__be64 *)nexus->i_port_id),
2217 			be64_to_cpu(*(__be64 *)(nexus->i_port_id + 8)));
2218 
2219 	pr_debug("registering session %s\n", ch->sess_name);
2220 
2221 	if (sport->port_guid_tpg.se_tpg_wwn)
2222 		ch->sess = target_setup_session(&sport->port_guid_tpg, 0, 0,
2223 						TARGET_PROT_NORMAL,
2224 						ch->sess_name, ch, NULL);
2225 	if (sport->port_gid_tpg.se_tpg_wwn && IS_ERR_OR_NULL(ch->sess))
2226 		ch->sess = target_setup_session(&sport->port_gid_tpg, 0, 0,
2227 					TARGET_PROT_NORMAL, i_port_id, ch,
2228 					NULL);
2229 	/* Retry without leading "0x" */
2230 	if (sport->port_gid_tpg.se_tpg_wwn && IS_ERR_OR_NULL(ch->sess))
2231 		ch->sess = target_setup_session(&sport->port_gid_tpg, 0, 0,
2232 						TARGET_PROT_NORMAL,
2233 						i_port_id + 2, ch, NULL);
2234 	if (IS_ERR_OR_NULL(ch->sess)) {
2235 		WARN_ON_ONCE(ch->sess == NULL);
2236 		ret = PTR_ERR(ch->sess);
2237 		ch->sess = NULL;
2238 		pr_info("Rejected login for initiator %s: ret = %d.\n",
2239 			ch->sess_name, ret);
2240 		rej->reason = cpu_to_be32(ret == -ENOMEM ?
2241 				SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES :
2242 				SRP_LOGIN_REJ_CHANNEL_LIMIT_REACHED);
2243 		goto destroy_ib;
2244 	}
2245 
2246 	mutex_lock(&sport->mutex);
2247 
2248 	if ((req->req_flags & SRP_MTCH_ACTION) == SRP_MULTICHAN_SINGLE) {
2249 		struct srpt_rdma_ch *ch2;
2250 
2251 		rsp->rsp_flags = SRP_LOGIN_RSP_MULTICHAN_NO_CHAN;
2252 
2253 		list_for_each_entry(ch2, &nexus->ch_list, list) {
2254 			if (srpt_disconnect_ch(ch2) < 0)
2255 				continue;
2256 			pr_info("Relogin - closed existing channel %s\n",
2257 				ch2->sess_name);
2258 			rsp->rsp_flags = SRP_LOGIN_RSP_MULTICHAN_TERMINATED;
2259 		}
2260 	} else {
2261 		rsp->rsp_flags = SRP_LOGIN_RSP_MULTICHAN_MAINTAINED;
2262 	}
2263 
2264 	list_add_tail_rcu(&ch->list, &nexus->ch_list);
2265 
2266 	if (!sport->enabled) {
2267 		rej->reason = cpu_to_be32(
2268 				SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
2269 		pr_info("rejected SRP_LOGIN_REQ because target %s_%d is not enabled\n",
2270 			sdev->device->name, port_num);
2271 		mutex_unlock(&sport->mutex);
2272 		goto reject;
2273 	}
2274 
2275 	mutex_unlock(&sport->mutex);
2276 
2277 	ret = ch->using_rdma_cm ? 0 : srpt_ch_qp_rtr(ch, ch->qp);
2278 	if (ret) {
2279 		rej->reason = cpu_to_be32(SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
2280 		pr_err("rejected SRP_LOGIN_REQ because enabling RTR failed (error code = %d)\n",
2281 		       ret);
2282 		goto reject;
2283 	}
2284 
2285 	pr_debug("Establish connection sess=%p name=%s ch=%p\n", ch->sess,
2286 		 ch->sess_name, ch);
2287 
2288 	/* create srp_login_response */
2289 	rsp->opcode = SRP_LOGIN_RSP;
2290 	rsp->tag = req->tag;
2291 	rsp->max_it_iu_len = req->req_it_iu_len;
2292 	rsp->max_ti_iu_len = req->req_it_iu_len;
2293 	ch->max_ti_iu_len = it_iu_len;
2294 	rsp->buf_fmt = cpu_to_be16(SRP_BUF_FORMAT_DIRECT |
2295 				   SRP_BUF_FORMAT_INDIRECT);
2296 	rsp->req_lim_delta = cpu_to_be32(ch->rq_size);
2297 	atomic_set(&ch->req_lim, ch->rq_size);
2298 	atomic_set(&ch->req_lim_delta, 0);
2299 
2300 	/* create cm reply */
2301 	if (ch->using_rdma_cm) {
2302 		rep_param->rdma_cm.private_data = (void *)rsp;
2303 		rep_param->rdma_cm.private_data_len = sizeof(*rsp);
2304 		rep_param->rdma_cm.rnr_retry_count = 7;
2305 		rep_param->rdma_cm.flow_control = 1;
2306 		rep_param->rdma_cm.responder_resources = 4;
2307 		rep_param->rdma_cm.initiator_depth = 4;
2308 	} else {
2309 		rep_param->ib_cm.qp_num = ch->qp->qp_num;
2310 		rep_param->ib_cm.private_data = (void *)rsp;
2311 		rep_param->ib_cm.private_data_len = sizeof(*rsp);
2312 		rep_param->ib_cm.rnr_retry_count = 7;
2313 		rep_param->ib_cm.flow_control = 1;
2314 		rep_param->ib_cm.failover_accepted = 0;
2315 		rep_param->ib_cm.srq = 1;
2316 		rep_param->ib_cm.responder_resources = 4;
2317 		rep_param->ib_cm.initiator_depth = 4;
2318 	}
2319 
2320 	/*
2321 	 * Hold the sport mutex while accepting a connection to avoid that
2322 	 * srpt_disconnect_ch() is invoked concurrently with this code.
2323 	 */
2324 	mutex_lock(&sport->mutex);
2325 	if (sport->enabled && ch->state == CH_CONNECTING) {
2326 		if (ch->using_rdma_cm)
2327 			ret = rdma_accept(rdma_cm_id, &rep_param->rdma_cm);
2328 		else
2329 			ret = ib_send_cm_rep(ib_cm_id, &rep_param->ib_cm);
2330 	} else {
2331 		ret = -EINVAL;
2332 	}
2333 	mutex_unlock(&sport->mutex);
2334 
2335 	switch (ret) {
2336 	case 0:
2337 		break;
2338 	case -EINVAL:
2339 		goto reject;
2340 	default:
2341 		rej->reason = cpu_to_be32(SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
2342 		pr_err("sending SRP_LOGIN_REQ response failed (error code = %d)\n",
2343 		       ret);
2344 		goto reject;
2345 	}
2346 
2347 	goto out;
2348 
2349 destroy_ib:
2350 	srpt_destroy_ch_ib(ch);
2351 
2352 free_recv_ring:
2353 	srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_recv_ring,
2354 			     ch->sport->sdev, ch->rq_size,
2355 			     srp_max_req_size, DMA_FROM_DEVICE);
2356 
2357 free_ring:
2358 	srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_ring,
2359 			     ch->sport->sdev, ch->rq_size,
2360 			     ch->max_rsp_size, DMA_TO_DEVICE);
2361 
2362 free_ch:
2363 	if (rdma_cm_id)
2364 		rdma_cm_id->context = NULL;
2365 	else
2366 		ib_cm_id->context = NULL;
2367 	kfree(ch);
2368 	ch = NULL;
2369 
2370 	WARN_ON_ONCE(ret == 0);
2371 
2372 reject:
2373 	pr_info("Rejecting login with reason %#x\n", be32_to_cpu(rej->reason));
2374 	rej->opcode = SRP_LOGIN_REJ;
2375 	rej->tag = req->tag;
2376 	rej->buf_fmt = cpu_to_be16(SRP_BUF_FORMAT_DIRECT |
2377 				   SRP_BUF_FORMAT_INDIRECT);
2378 
2379 	if (rdma_cm_id)
2380 		rdma_reject(rdma_cm_id, rej, sizeof(*rej));
2381 	else
2382 		ib_send_cm_rej(ib_cm_id, IB_CM_REJ_CONSUMER_DEFINED, NULL, 0,
2383 			       rej, sizeof(*rej));
2384 
2385 	if (ch && ch->sess) {
2386 		srpt_close_ch(ch);
2387 		/*
2388 		 * Tell the caller not to free cm_id since
2389 		 * srpt_release_channel_work() will do that.
2390 		 */
2391 		ret = 0;
2392 	}
2393 
2394 out:
2395 	kfree(rep_param);
2396 	kfree(rsp);
2397 	kfree(rej);
2398 
2399 	return ret;
2400 }
2401 
2402 static int srpt_ib_cm_req_recv(struct ib_cm_id *cm_id,
2403 			       const struct ib_cm_req_event_param *param,
2404 			       void *private_data)
2405 {
2406 	char sguid[40];
2407 
2408 	srpt_format_guid(sguid, sizeof(sguid),
2409 			 &param->primary_path->dgid.global.interface_id);
2410 
2411 	return srpt_cm_req_recv(cm_id->context, cm_id, NULL, param->port,
2412 				param->primary_path->pkey,
2413 				private_data, sguid);
2414 }
2415 
2416 static int srpt_rdma_cm_req_recv(struct rdma_cm_id *cm_id,
2417 				 struct rdma_cm_event *event)
2418 {
2419 	struct srpt_device *sdev;
2420 	struct srp_login_req req;
2421 	const struct srp_login_req_rdma *req_rdma;
2422 	char src_addr[40];
2423 
2424 	sdev = ib_get_client_data(cm_id->device, &srpt_client);
2425 	if (!sdev)
2426 		return -ECONNREFUSED;
2427 
2428 	if (event->param.conn.private_data_len < sizeof(*req_rdma))
2429 		return -EINVAL;
2430 
2431 	/* Transform srp_login_req_rdma into srp_login_req. */
2432 	req_rdma = event->param.conn.private_data;
2433 	memset(&req, 0, sizeof(req));
2434 	req.opcode		= req_rdma->opcode;
2435 	req.tag			= req_rdma->tag;
2436 	req.req_it_iu_len	= req_rdma->req_it_iu_len;
2437 	req.req_buf_fmt		= req_rdma->req_buf_fmt;
2438 	req.req_flags		= req_rdma->req_flags;
2439 	memcpy(req.initiator_port_id, req_rdma->initiator_port_id, 16);
2440 	memcpy(req.target_port_id, req_rdma->target_port_id, 16);
2441 
2442 	snprintf(src_addr, sizeof(src_addr), "%pIS",
2443 		 &cm_id->route.addr.src_addr);
2444 
2445 	return srpt_cm_req_recv(sdev, NULL, cm_id, cm_id->port_num,
2446 				cm_id->route.path_rec->pkey, &req, src_addr);
2447 }
2448 
2449 static void srpt_cm_rej_recv(struct srpt_rdma_ch *ch,
2450 			     enum ib_cm_rej_reason reason,
2451 			     const u8 *private_data,
2452 			     u8 private_data_len)
2453 {
2454 	char *priv = NULL;
2455 	int i;
2456 
2457 	if (private_data_len && (priv = kmalloc(private_data_len * 3 + 1,
2458 						GFP_KERNEL))) {
2459 		for (i = 0; i < private_data_len; i++)
2460 			sprintf(priv + 3 * i, " %02x", private_data[i]);
2461 	}
2462 	pr_info("Received CM REJ for ch %s-%d; reason %d%s%s.\n",
2463 		ch->sess_name, ch->qp->qp_num, reason, private_data_len ?
2464 		"; private data" : "", priv ? priv : " (?)");
2465 	kfree(priv);
2466 }
2467 
2468 /**
2469  * srpt_cm_rtu_recv - process an IB_CM_RTU_RECEIVED or USER_ESTABLISHED event
2470  * @ch: SRPT RDMA channel.
2471  *
2472  * An RTU (ready to use) message indicates that the connection has been
2473  * established and that the recipient may begin transmitting.
2474  */
2475 static void srpt_cm_rtu_recv(struct srpt_rdma_ch *ch)
2476 {
2477 	int ret;
2478 
2479 	ret = ch->using_rdma_cm ? 0 : srpt_ch_qp_rts(ch, ch->qp);
2480 	if (ret < 0) {
2481 		pr_err("%s-%d: QP transition to RTS failed\n", ch->sess_name,
2482 		       ch->qp->qp_num);
2483 		srpt_close_ch(ch);
2484 		return;
2485 	}
2486 
2487 	/*
2488 	 * Note: calling srpt_close_ch() if the transition to the LIVE state
2489 	 * fails is not necessary since that means that that function has
2490 	 * already been invoked from another thread.
2491 	 */
2492 	if (!srpt_set_ch_state(ch, CH_LIVE)) {
2493 		pr_err("%s-%d: channel transition to LIVE state failed\n",
2494 		       ch->sess_name, ch->qp->qp_num);
2495 		return;
2496 	}
2497 
2498 	/* Trigger wait list processing. */
2499 	ret = srpt_zerolength_write(ch);
2500 	WARN_ONCE(ret < 0, "%d\n", ret);
2501 }
2502 
2503 /**
2504  * srpt_cm_handler - IB connection manager callback function
2505  * @cm_id: IB/CM connection identifier.
2506  * @event: IB/CM event.
2507  *
2508  * A non-zero return value will cause the caller destroy the CM ID.
2509  *
2510  * Note: srpt_cm_handler() must only return a non-zero value when transferring
2511  * ownership of the cm_id to a channel by srpt_cm_req_recv() failed. Returning
2512  * a non-zero value in any other case will trigger a race with the
2513  * ib_destroy_cm_id() call in srpt_release_channel().
2514  */
2515 static int srpt_cm_handler(struct ib_cm_id *cm_id,
2516 			   const struct ib_cm_event *event)
2517 {
2518 	struct srpt_rdma_ch *ch = cm_id->context;
2519 	int ret;
2520 
2521 	ret = 0;
2522 	switch (event->event) {
2523 	case IB_CM_REQ_RECEIVED:
2524 		ret = srpt_ib_cm_req_recv(cm_id, &event->param.req_rcvd,
2525 					  event->private_data);
2526 		break;
2527 	case IB_CM_REJ_RECEIVED:
2528 		srpt_cm_rej_recv(ch, event->param.rej_rcvd.reason,
2529 				 event->private_data,
2530 				 IB_CM_REJ_PRIVATE_DATA_SIZE);
2531 		break;
2532 	case IB_CM_RTU_RECEIVED:
2533 	case IB_CM_USER_ESTABLISHED:
2534 		srpt_cm_rtu_recv(ch);
2535 		break;
2536 	case IB_CM_DREQ_RECEIVED:
2537 		srpt_disconnect_ch(ch);
2538 		break;
2539 	case IB_CM_DREP_RECEIVED:
2540 		pr_info("Received CM DREP message for ch %s-%d.\n",
2541 			ch->sess_name, ch->qp->qp_num);
2542 		srpt_close_ch(ch);
2543 		break;
2544 	case IB_CM_TIMEWAIT_EXIT:
2545 		pr_info("Received CM TimeWait exit for ch %s-%d.\n",
2546 			ch->sess_name, ch->qp->qp_num);
2547 		srpt_close_ch(ch);
2548 		break;
2549 	case IB_CM_REP_ERROR:
2550 		pr_info("Received CM REP error for ch %s-%d.\n", ch->sess_name,
2551 			ch->qp->qp_num);
2552 		break;
2553 	case IB_CM_DREQ_ERROR:
2554 		pr_info("Received CM DREQ ERROR event.\n");
2555 		break;
2556 	case IB_CM_MRA_RECEIVED:
2557 		pr_info("Received CM MRA event\n");
2558 		break;
2559 	default:
2560 		pr_err("received unrecognized CM event %d\n", event->event);
2561 		break;
2562 	}
2563 
2564 	return ret;
2565 }
2566 
2567 static int srpt_rdma_cm_handler(struct rdma_cm_id *cm_id,
2568 				struct rdma_cm_event *event)
2569 {
2570 	struct srpt_rdma_ch *ch = cm_id->context;
2571 	int ret = 0;
2572 
2573 	switch (event->event) {
2574 	case RDMA_CM_EVENT_CONNECT_REQUEST:
2575 		ret = srpt_rdma_cm_req_recv(cm_id, event);
2576 		break;
2577 	case RDMA_CM_EVENT_REJECTED:
2578 		srpt_cm_rej_recv(ch, event->status,
2579 				 event->param.conn.private_data,
2580 				 event->param.conn.private_data_len);
2581 		break;
2582 	case RDMA_CM_EVENT_ESTABLISHED:
2583 		srpt_cm_rtu_recv(ch);
2584 		break;
2585 	case RDMA_CM_EVENT_DISCONNECTED:
2586 		if (ch->state < CH_DISCONNECTING)
2587 			srpt_disconnect_ch(ch);
2588 		else
2589 			srpt_close_ch(ch);
2590 		break;
2591 	case RDMA_CM_EVENT_TIMEWAIT_EXIT:
2592 		srpt_close_ch(ch);
2593 		break;
2594 	case RDMA_CM_EVENT_UNREACHABLE:
2595 		pr_info("Received CM REP error for ch %s-%d.\n", ch->sess_name,
2596 			ch->qp->qp_num);
2597 		break;
2598 	case RDMA_CM_EVENT_DEVICE_REMOVAL:
2599 	case RDMA_CM_EVENT_ADDR_CHANGE:
2600 		break;
2601 	default:
2602 		pr_err("received unrecognized RDMA CM event %d\n",
2603 		       event->event);
2604 		break;
2605 	}
2606 
2607 	return ret;
2608 }
2609 
2610 static int srpt_write_pending_status(struct se_cmd *se_cmd)
2611 {
2612 	struct srpt_send_ioctx *ioctx;
2613 
2614 	ioctx = container_of(se_cmd, struct srpt_send_ioctx, cmd);
2615 	return ioctx->state == SRPT_STATE_NEED_DATA;
2616 }
2617 
2618 /*
2619  * srpt_write_pending - Start data transfer from initiator to target (write).
2620  */
2621 static int srpt_write_pending(struct se_cmd *se_cmd)
2622 {
2623 	struct srpt_send_ioctx *ioctx =
2624 		container_of(se_cmd, struct srpt_send_ioctx, cmd);
2625 	struct srpt_rdma_ch *ch = ioctx->ch;
2626 	struct ib_send_wr *first_wr = NULL;
2627 	struct ib_cqe *cqe = &ioctx->rdma_cqe;
2628 	enum srpt_command_state new_state;
2629 	int ret, i;
2630 
2631 	new_state = srpt_set_cmd_state(ioctx, SRPT_STATE_NEED_DATA);
2632 	WARN_ON(new_state == SRPT_STATE_DONE);
2633 
2634 	if (atomic_sub_return(ioctx->n_rdma, &ch->sq_wr_avail) < 0) {
2635 		pr_warn("%s: IB send queue full (needed %d)\n",
2636 				__func__, ioctx->n_rdma);
2637 		ret = -ENOMEM;
2638 		goto out_undo;
2639 	}
2640 
2641 	cqe->done = srpt_rdma_read_done;
2642 	for (i = ioctx->n_rw_ctx - 1; i >= 0; i--) {
2643 		struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
2644 
2645 		first_wr = rdma_rw_ctx_wrs(&ctx->rw, ch->qp, ch->sport->port,
2646 				cqe, first_wr);
2647 		cqe = NULL;
2648 	}
2649 
2650 	ret = ib_post_send(ch->qp, first_wr, NULL);
2651 	if (ret) {
2652 		pr_err("%s: ib_post_send() returned %d for %d (avail: %d)\n",
2653 			 __func__, ret, ioctx->n_rdma,
2654 			 atomic_read(&ch->sq_wr_avail));
2655 		goto out_undo;
2656 	}
2657 
2658 	return 0;
2659 out_undo:
2660 	atomic_add(ioctx->n_rdma, &ch->sq_wr_avail);
2661 	return ret;
2662 }
2663 
2664 static u8 tcm_to_srp_tsk_mgmt_status(const int tcm_mgmt_status)
2665 {
2666 	switch (tcm_mgmt_status) {
2667 	case TMR_FUNCTION_COMPLETE:
2668 		return SRP_TSK_MGMT_SUCCESS;
2669 	case TMR_FUNCTION_REJECTED:
2670 		return SRP_TSK_MGMT_FUNC_NOT_SUPP;
2671 	}
2672 	return SRP_TSK_MGMT_FAILED;
2673 }
2674 
2675 /**
2676  * srpt_queue_response - transmit the response to a SCSI command
2677  * @cmd: SCSI target command.
2678  *
2679  * Callback function called by the TCM core. Must not block since it can be
2680  * invoked on the context of the IB completion handler.
2681  */
2682 static void srpt_queue_response(struct se_cmd *cmd)
2683 {
2684 	struct srpt_send_ioctx *ioctx =
2685 		container_of(cmd, struct srpt_send_ioctx, cmd);
2686 	struct srpt_rdma_ch *ch = ioctx->ch;
2687 	struct srpt_device *sdev = ch->sport->sdev;
2688 	struct ib_send_wr send_wr, *first_wr = &send_wr;
2689 	struct ib_sge sge;
2690 	enum srpt_command_state state;
2691 	int resp_len, ret, i;
2692 	u8 srp_tm_status;
2693 
2694 	BUG_ON(!ch);
2695 
2696 	state = ioctx->state;
2697 	switch (state) {
2698 	case SRPT_STATE_NEW:
2699 	case SRPT_STATE_DATA_IN:
2700 		ioctx->state = SRPT_STATE_CMD_RSP_SENT;
2701 		break;
2702 	case SRPT_STATE_MGMT:
2703 		ioctx->state = SRPT_STATE_MGMT_RSP_SENT;
2704 		break;
2705 	default:
2706 		WARN(true, "ch %p; cmd %d: unexpected command state %d\n",
2707 			ch, ioctx->ioctx.index, ioctx->state);
2708 		break;
2709 	}
2710 
2711 	if (unlikely(WARN_ON_ONCE(state == SRPT_STATE_CMD_RSP_SENT)))
2712 		return;
2713 
2714 	/* For read commands, transfer the data to the initiator. */
2715 	if (ioctx->cmd.data_direction == DMA_FROM_DEVICE &&
2716 	    ioctx->cmd.data_length &&
2717 	    !ioctx->queue_status_only) {
2718 		for (i = ioctx->n_rw_ctx - 1; i >= 0; i--) {
2719 			struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
2720 
2721 			first_wr = rdma_rw_ctx_wrs(&ctx->rw, ch->qp,
2722 					ch->sport->port, NULL, first_wr);
2723 		}
2724 	}
2725 
2726 	if (state != SRPT_STATE_MGMT)
2727 		resp_len = srpt_build_cmd_rsp(ch, ioctx, ioctx->cmd.tag,
2728 					      cmd->scsi_status);
2729 	else {
2730 		srp_tm_status
2731 			= tcm_to_srp_tsk_mgmt_status(cmd->se_tmr_req->response);
2732 		resp_len = srpt_build_tskmgmt_rsp(ch, ioctx, srp_tm_status,
2733 						 ioctx->cmd.tag);
2734 	}
2735 
2736 	atomic_inc(&ch->req_lim);
2737 
2738 	if (unlikely(atomic_sub_return(1 + ioctx->n_rdma,
2739 			&ch->sq_wr_avail) < 0)) {
2740 		pr_warn("%s: IB send queue full (needed %d)\n",
2741 				__func__, ioctx->n_rdma);
2742 		ret = -ENOMEM;
2743 		goto out;
2744 	}
2745 
2746 	ib_dma_sync_single_for_device(sdev->device, ioctx->ioctx.dma, resp_len,
2747 				      DMA_TO_DEVICE);
2748 
2749 	sge.addr = ioctx->ioctx.dma;
2750 	sge.length = resp_len;
2751 	sge.lkey = sdev->lkey;
2752 
2753 	ioctx->ioctx.cqe.done = srpt_send_done;
2754 	send_wr.next = NULL;
2755 	send_wr.wr_cqe = &ioctx->ioctx.cqe;
2756 	send_wr.sg_list = &sge;
2757 	send_wr.num_sge = 1;
2758 	send_wr.opcode = IB_WR_SEND;
2759 	send_wr.send_flags = IB_SEND_SIGNALED;
2760 
2761 	ret = ib_post_send(ch->qp, first_wr, NULL);
2762 	if (ret < 0) {
2763 		pr_err("%s: sending cmd response failed for tag %llu (%d)\n",
2764 			__func__, ioctx->cmd.tag, ret);
2765 		goto out;
2766 	}
2767 
2768 	return;
2769 
2770 out:
2771 	atomic_add(1 + ioctx->n_rdma, &ch->sq_wr_avail);
2772 	atomic_dec(&ch->req_lim);
2773 	srpt_set_cmd_state(ioctx, SRPT_STATE_DONE);
2774 	target_put_sess_cmd(&ioctx->cmd);
2775 }
2776 
2777 static int srpt_queue_data_in(struct se_cmd *cmd)
2778 {
2779 	srpt_queue_response(cmd);
2780 	return 0;
2781 }
2782 
2783 static void srpt_queue_tm_rsp(struct se_cmd *cmd)
2784 {
2785 	srpt_queue_response(cmd);
2786 }
2787 
2788 static void srpt_aborted_task(struct se_cmd *cmd)
2789 {
2790 }
2791 
2792 static int srpt_queue_status(struct se_cmd *cmd)
2793 {
2794 	struct srpt_send_ioctx *ioctx;
2795 
2796 	ioctx = container_of(cmd, struct srpt_send_ioctx, cmd);
2797 	BUG_ON(ioctx->sense_data != cmd->sense_buffer);
2798 	if (cmd->se_cmd_flags &
2799 	    (SCF_TRANSPORT_TASK_SENSE | SCF_EMULATED_TASK_SENSE))
2800 		WARN_ON(cmd->scsi_status != SAM_STAT_CHECK_CONDITION);
2801 	ioctx->queue_status_only = true;
2802 	srpt_queue_response(cmd);
2803 	return 0;
2804 }
2805 
2806 static void srpt_refresh_port_work(struct work_struct *work)
2807 {
2808 	struct srpt_port *sport = container_of(work, struct srpt_port, work);
2809 
2810 	srpt_refresh_port(sport);
2811 }
2812 
2813 static bool srpt_ch_list_empty(struct srpt_port *sport)
2814 {
2815 	struct srpt_nexus *nexus;
2816 	bool res = true;
2817 
2818 	rcu_read_lock();
2819 	list_for_each_entry(nexus, &sport->nexus_list, entry)
2820 		if (!list_empty(&nexus->ch_list))
2821 			res = false;
2822 	rcu_read_unlock();
2823 
2824 	return res;
2825 }
2826 
2827 /**
2828  * srpt_release_sport - disable login and wait for associated channels
2829  * @sport: SRPT HCA port.
2830  */
2831 static int srpt_release_sport(struct srpt_port *sport)
2832 {
2833 	struct srpt_nexus *nexus, *next_n;
2834 	struct srpt_rdma_ch *ch;
2835 
2836 	WARN_ON_ONCE(irqs_disabled());
2837 
2838 	mutex_lock(&sport->mutex);
2839 	srpt_set_enabled(sport, false);
2840 	mutex_unlock(&sport->mutex);
2841 
2842 	while (wait_event_timeout(sport->ch_releaseQ,
2843 				  srpt_ch_list_empty(sport), 5 * HZ) <= 0) {
2844 		pr_info("%s_%d: waiting for session unregistration ...\n",
2845 			sport->sdev->device->name, sport->port);
2846 		rcu_read_lock();
2847 		list_for_each_entry(nexus, &sport->nexus_list, entry) {
2848 			list_for_each_entry(ch, &nexus->ch_list, list) {
2849 				pr_info("%s-%d: state %s\n",
2850 					ch->sess_name, ch->qp->qp_num,
2851 					get_ch_state_name(ch->state));
2852 			}
2853 		}
2854 		rcu_read_unlock();
2855 	}
2856 
2857 	mutex_lock(&sport->mutex);
2858 	list_for_each_entry_safe(nexus, next_n, &sport->nexus_list, entry) {
2859 		list_del(&nexus->entry);
2860 		kfree_rcu(nexus, rcu);
2861 	}
2862 	mutex_unlock(&sport->mutex);
2863 
2864 	return 0;
2865 }
2866 
2867 static struct se_wwn *__srpt_lookup_wwn(const char *name)
2868 {
2869 	struct ib_device *dev;
2870 	struct srpt_device *sdev;
2871 	struct srpt_port *sport;
2872 	int i;
2873 
2874 	list_for_each_entry(sdev, &srpt_dev_list, list) {
2875 		dev = sdev->device;
2876 		if (!dev)
2877 			continue;
2878 
2879 		for (i = 0; i < dev->phys_port_cnt; i++) {
2880 			sport = &sdev->port[i];
2881 
2882 			if (strcmp(sport->port_guid, name) == 0)
2883 				return &sport->port_guid_wwn;
2884 			if (strcmp(sport->port_gid, name) == 0)
2885 				return &sport->port_gid_wwn;
2886 		}
2887 	}
2888 
2889 	return NULL;
2890 }
2891 
2892 static struct se_wwn *srpt_lookup_wwn(const char *name)
2893 {
2894 	struct se_wwn *wwn;
2895 
2896 	spin_lock(&srpt_dev_lock);
2897 	wwn = __srpt_lookup_wwn(name);
2898 	spin_unlock(&srpt_dev_lock);
2899 
2900 	return wwn;
2901 }
2902 
2903 static void srpt_free_srq(struct srpt_device *sdev)
2904 {
2905 	if (!sdev->srq)
2906 		return;
2907 
2908 	ib_destroy_srq(sdev->srq);
2909 	srpt_free_ioctx_ring((struct srpt_ioctx **)sdev->ioctx_ring, sdev,
2910 			     sdev->srq_size, srp_max_req_size, DMA_FROM_DEVICE);
2911 	sdev->srq = NULL;
2912 }
2913 
2914 static int srpt_alloc_srq(struct srpt_device *sdev)
2915 {
2916 	struct ib_srq_init_attr srq_attr = {
2917 		.event_handler = srpt_srq_event,
2918 		.srq_context = (void *)sdev,
2919 		.attr.max_wr = sdev->srq_size,
2920 		.attr.max_sge = 1,
2921 		.srq_type = IB_SRQT_BASIC,
2922 	};
2923 	struct ib_device *device = sdev->device;
2924 	struct ib_srq *srq;
2925 	int i;
2926 
2927 	WARN_ON_ONCE(sdev->srq);
2928 	srq = ib_create_srq(sdev->pd, &srq_attr);
2929 	if (IS_ERR(srq)) {
2930 		pr_debug("ib_create_srq() failed: %ld\n", PTR_ERR(srq));
2931 		return PTR_ERR(srq);
2932 	}
2933 
2934 	pr_debug("create SRQ #wr= %d max_allow=%d dev= %s\n", sdev->srq_size,
2935 		 sdev->device->attrs.max_srq_wr, device->name);
2936 
2937 	sdev->ioctx_ring = (struct srpt_recv_ioctx **)
2938 		srpt_alloc_ioctx_ring(sdev, sdev->srq_size,
2939 				      sizeof(*sdev->ioctx_ring[0]),
2940 				      srp_max_req_size, DMA_FROM_DEVICE);
2941 	if (!sdev->ioctx_ring) {
2942 		ib_destroy_srq(srq);
2943 		return -ENOMEM;
2944 	}
2945 
2946 	sdev->use_srq = true;
2947 	sdev->srq = srq;
2948 
2949 	for (i = 0; i < sdev->srq_size; ++i) {
2950 		INIT_LIST_HEAD(&sdev->ioctx_ring[i]->wait_list);
2951 		srpt_post_recv(sdev, NULL, sdev->ioctx_ring[i]);
2952 	}
2953 
2954 	return 0;
2955 }
2956 
2957 static int srpt_use_srq(struct srpt_device *sdev, bool use_srq)
2958 {
2959 	struct ib_device *device = sdev->device;
2960 	int ret = 0;
2961 
2962 	if (!use_srq) {
2963 		srpt_free_srq(sdev);
2964 		sdev->use_srq = false;
2965 	} else if (use_srq && !sdev->srq) {
2966 		ret = srpt_alloc_srq(sdev);
2967 	}
2968 	pr_debug("%s(%s): use_srq = %d; ret = %d\n", __func__, device->name,
2969 		 sdev->use_srq, ret);
2970 	return ret;
2971 }
2972 
2973 /**
2974  * srpt_add_one - InfiniBand device addition callback function
2975  * @device: Describes a HCA.
2976  */
2977 static void srpt_add_one(struct ib_device *device)
2978 {
2979 	struct srpt_device *sdev;
2980 	struct srpt_port *sport;
2981 	int i, ret;
2982 
2983 	pr_debug("device = %p\n", device);
2984 
2985 	sdev = kzalloc(struct_size(sdev, port, device->phys_port_cnt),
2986 		       GFP_KERNEL);
2987 	if (!sdev)
2988 		goto err;
2989 
2990 	sdev->device = device;
2991 	mutex_init(&sdev->sdev_mutex);
2992 
2993 	sdev->pd = ib_alloc_pd(device, 0);
2994 	if (IS_ERR(sdev->pd))
2995 		goto free_dev;
2996 
2997 	sdev->lkey = sdev->pd->local_dma_lkey;
2998 
2999 	sdev->srq_size = min(srpt_srq_size, sdev->device->attrs.max_srq_wr);
3000 
3001 	srpt_use_srq(sdev, sdev->port[0].port_attrib.use_srq);
3002 
3003 	if (!srpt_service_guid)
3004 		srpt_service_guid = be64_to_cpu(device->node_guid);
3005 
3006 	if (rdma_port_get_link_layer(device, 1) == IB_LINK_LAYER_INFINIBAND)
3007 		sdev->cm_id = ib_create_cm_id(device, srpt_cm_handler, sdev);
3008 	if (IS_ERR(sdev->cm_id)) {
3009 		pr_info("ib_create_cm_id() failed: %ld\n",
3010 			PTR_ERR(sdev->cm_id));
3011 		sdev->cm_id = NULL;
3012 		if (!rdma_cm_id)
3013 			goto err_ring;
3014 	}
3015 
3016 	/* print out target login information */
3017 	pr_debug("Target login info: id_ext=%016llx,ioc_guid=%016llx,"
3018 		 "pkey=ffff,service_id=%016llx\n", srpt_service_guid,
3019 		 srpt_service_guid, srpt_service_guid);
3020 
3021 	/*
3022 	 * We do not have a consistent service_id (ie. also id_ext of target_id)
3023 	 * to identify this target. We currently use the guid of the first HCA
3024 	 * in the system as service_id; therefore, the target_id will change
3025 	 * if this HCA is gone bad and replaced by different HCA
3026 	 */
3027 	ret = sdev->cm_id ?
3028 		ib_cm_listen(sdev->cm_id, cpu_to_be64(srpt_service_guid), 0) :
3029 		0;
3030 	if (ret < 0) {
3031 		pr_err("ib_cm_listen() failed: %d (cm_id state = %d)\n", ret,
3032 		       sdev->cm_id->state);
3033 		goto err_cm;
3034 	}
3035 
3036 	INIT_IB_EVENT_HANDLER(&sdev->event_handler, sdev->device,
3037 			      srpt_event_handler);
3038 	ib_register_event_handler(&sdev->event_handler);
3039 
3040 	for (i = 1; i <= sdev->device->phys_port_cnt; i++) {
3041 		sport = &sdev->port[i - 1];
3042 		INIT_LIST_HEAD(&sport->nexus_list);
3043 		init_waitqueue_head(&sport->ch_releaseQ);
3044 		mutex_init(&sport->mutex);
3045 		sport->sdev = sdev;
3046 		sport->port = i;
3047 		sport->port_attrib.srp_max_rdma_size = DEFAULT_MAX_RDMA_SIZE;
3048 		sport->port_attrib.srp_max_rsp_size = DEFAULT_MAX_RSP_SIZE;
3049 		sport->port_attrib.srp_sq_size = DEF_SRPT_SQ_SIZE;
3050 		sport->port_attrib.use_srq = false;
3051 		INIT_WORK(&sport->work, srpt_refresh_port_work);
3052 
3053 		if (srpt_refresh_port(sport)) {
3054 			pr_err("MAD registration failed for %s-%d.\n",
3055 			       sdev->device->name, i);
3056 			goto err_event;
3057 		}
3058 	}
3059 
3060 	spin_lock(&srpt_dev_lock);
3061 	list_add_tail(&sdev->list, &srpt_dev_list);
3062 	spin_unlock(&srpt_dev_lock);
3063 
3064 out:
3065 	ib_set_client_data(device, &srpt_client, sdev);
3066 	pr_debug("added %s.\n", device->name);
3067 	return;
3068 
3069 err_event:
3070 	ib_unregister_event_handler(&sdev->event_handler);
3071 err_cm:
3072 	if (sdev->cm_id)
3073 		ib_destroy_cm_id(sdev->cm_id);
3074 err_ring:
3075 	srpt_free_srq(sdev);
3076 	ib_dealloc_pd(sdev->pd);
3077 free_dev:
3078 	kfree(sdev);
3079 err:
3080 	sdev = NULL;
3081 	pr_info("%s(%s) failed.\n", __func__, device->name);
3082 	goto out;
3083 }
3084 
3085 /**
3086  * srpt_remove_one - InfiniBand device removal callback function
3087  * @device: Describes a HCA.
3088  * @client_data: The value passed as the third argument to ib_set_client_data().
3089  */
3090 static void srpt_remove_one(struct ib_device *device, void *client_data)
3091 {
3092 	struct srpt_device *sdev = client_data;
3093 	int i;
3094 
3095 	if (!sdev) {
3096 		pr_info("%s(%s): nothing to do.\n", __func__, device->name);
3097 		return;
3098 	}
3099 
3100 	srpt_unregister_mad_agent(sdev);
3101 
3102 	ib_unregister_event_handler(&sdev->event_handler);
3103 
3104 	/* Cancel any work queued by the just unregistered IB event handler. */
3105 	for (i = 0; i < sdev->device->phys_port_cnt; i++)
3106 		cancel_work_sync(&sdev->port[i].work);
3107 
3108 	if (sdev->cm_id)
3109 		ib_destroy_cm_id(sdev->cm_id);
3110 
3111 	ib_set_client_data(device, &srpt_client, NULL);
3112 
3113 	/*
3114 	 * Unregistering a target must happen after destroying sdev->cm_id
3115 	 * such that no new SRP_LOGIN_REQ information units can arrive while
3116 	 * destroying the target.
3117 	 */
3118 	spin_lock(&srpt_dev_lock);
3119 	list_del(&sdev->list);
3120 	spin_unlock(&srpt_dev_lock);
3121 
3122 	for (i = 0; i < sdev->device->phys_port_cnt; i++)
3123 		srpt_release_sport(&sdev->port[i]);
3124 
3125 	srpt_free_srq(sdev);
3126 
3127 	ib_dealloc_pd(sdev->pd);
3128 
3129 	kfree(sdev);
3130 }
3131 
3132 static struct ib_client srpt_client = {
3133 	.name = DRV_NAME,
3134 	.add = srpt_add_one,
3135 	.remove = srpt_remove_one
3136 };
3137 
3138 static int srpt_check_true(struct se_portal_group *se_tpg)
3139 {
3140 	return 1;
3141 }
3142 
3143 static int srpt_check_false(struct se_portal_group *se_tpg)
3144 {
3145 	return 0;
3146 }
3147 
3148 static char *srpt_get_fabric_name(void)
3149 {
3150 	return "srpt";
3151 }
3152 
3153 static struct srpt_port *srpt_tpg_to_sport(struct se_portal_group *tpg)
3154 {
3155 	return tpg->se_tpg_wwn->priv;
3156 }
3157 
3158 static char *srpt_get_fabric_wwn(struct se_portal_group *tpg)
3159 {
3160 	struct srpt_port *sport = srpt_tpg_to_sport(tpg);
3161 
3162 	WARN_ON_ONCE(tpg != &sport->port_guid_tpg &&
3163 		     tpg != &sport->port_gid_tpg);
3164 	return tpg == &sport->port_guid_tpg ? sport->port_guid :
3165 		sport->port_gid;
3166 }
3167 
3168 static u16 srpt_get_tag(struct se_portal_group *tpg)
3169 {
3170 	return 1;
3171 }
3172 
3173 static u32 srpt_tpg_get_inst_index(struct se_portal_group *se_tpg)
3174 {
3175 	return 1;
3176 }
3177 
3178 static void srpt_release_cmd(struct se_cmd *se_cmd)
3179 {
3180 	struct srpt_send_ioctx *ioctx = container_of(se_cmd,
3181 				struct srpt_send_ioctx, cmd);
3182 	struct srpt_rdma_ch *ch = ioctx->ch;
3183 	unsigned long flags;
3184 
3185 	WARN_ON_ONCE(ioctx->state != SRPT_STATE_DONE &&
3186 		     !(ioctx->cmd.transport_state & CMD_T_ABORTED));
3187 
3188 	if (ioctx->n_rw_ctx) {
3189 		srpt_free_rw_ctxs(ch, ioctx);
3190 		ioctx->n_rw_ctx = 0;
3191 	}
3192 
3193 	spin_lock_irqsave(&ch->spinlock, flags);
3194 	list_add(&ioctx->free_list, &ch->free_list);
3195 	spin_unlock_irqrestore(&ch->spinlock, flags);
3196 }
3197 
3198 /**
3199  * srpt_close_session - forcibly close a session
3200  * @se_sess: SCSI target session.
3201  *
3202  * Callback function invoked by the TCM core to clean up sessions associated
3203  * with a node ACL when the user invokes
3204  * rmdir /sys/kernel/config/target/$driver/$port/$tpg/acls/$i_port_id
3205  */
3206 static void srpt_close_session(struct se_session *se_sess)
3207 {
3208 	struct srpt_rdma_ch *ch = se_sess->fabric_sess_ptr;
3209 
3210 	srpt_disconnect_ch_sync(ch);
3211 }
3212 
3213 /**
3214  * srpt_sess_get_index - return the value of scsiAttIntrPortIndex (SCSI-MIB)
3215  * @se_sess: SCSI target session.
3216  *
3217  * A quote from RFC 4455 (SCSI-MIB) about this MIB object:
3218  * This object represents an arbitrary integer used to uniquely identify a
3219  * particular attached remote initiator port to a particular SCSI target port
3220  * within a particular SCSI target device within a particular SCSI instance.
3221  */
3222 static u32 srpt_sess_get_index(struct se_session *se_sess)
3223 {
3224 	return 0;
3225 }
3226 
3227 static void srpt_set_default_node_attrs(struct se_node_acl *nacl)
3228 {
3229 }
3230 
3231 /* Note: only used from inside debug printk's by the TCM core. */
3232 static int srpt_get_tcm_cmd_state(struct se_cmd *se_cmd)
3233 {
3234 	struct srpt_send_ioctx *ioctx;
3235 
3236 	ioctx = container_of(se_cmd, struct srpt_send_ioctx, cmd);
3237 	return ioctx->state;
3238 }
3239 
3240 static int srpt_parse_guid(u64 *guid, const char *name)
3241 {
3242 	u16 w[4];
3243 	int ret = -EINVAL;
3244 
3245 	if (sscanf(name, "%hx:%hx:%hx:%hx", &w[0], &w[1], &w[2], &w[3]) != 4)
3246 		goto out;
3247 	*guid = get_unaligned_be64(w);
3248 	ret = 0;
3249 out:
3250 	return ret;
3251 }
3252 
3253 /**
3254  * srpt_parse_i_port_id - parse an initiator port ID
3255  * @name: ASCII representation of a 128-bit initiator port ID.
3256  * @i_port_id: Binary 128-bit port ID.
3257  */
3258 static int srpt_parse_i_port_id(u8 i_port_id[16], const char *name)
3259 {
3260 	const char *p;
3261 	unsigned len, count, leading_zero_bytes;
3262 	int ret;
3263 
3264 	p = name;
3265 	if (strncasecmp(p, "0x", 2) == 0)
3266 		p += 2;
3267 	ret = -EINVAL;
3268 	len = strlen(p);
3269 	if (len % 2)
3270 		goto out;
3271 	count = min(len / 2, 16U);
3272 	leading_zero_bytes = 16 - count;
3273 	memset(i_port_id, 0, leading_zero_bytes);
3274 	ret = hex2bin(i_port_id + leading_zero_bytes, p, count);
3275 
3276 out:
3277 	return ret;
3278 }
3279 
3280 /*
3281  * configfs callback function invoked for mkdir
3282  * /sys/kernel/config/target/$driver/$port/$tpg/acls/$i_port_id
3283  *
3284  * i_port_id must be an initiator port GUID, GID or IP address. See also the
3285  * target_alloc_session() calls in this driver. Examples of valid initiator
3286  * port IDs:
3287  * 0x0000000000000000505400fffe4a0b7b
3288  * 0000000000000000505400fffe4a0b7b
3289  * 5054:00ff:fe4a:0b7b
3290  * 192.168.122.76
3291  */
3292 static int srpt_init_nodeacl(struct se_node_acl *se_nacl, const char *name)
3293 {
3294 	struct sockaddr_storage sa;
3295 	u64 guid;
3296 	u8 i_port_id[16];
3297 	int ret;
3298 
3299 	ret = srpt_parse_guid(&guid, name);
3300 	if (ret < 0)
3301 		ret = srpt_parse_i_port_id(i_port_id, name);
3302 	if (ret < 0)
3303 		ret = inet_pton_with_scope(&init_net, AF_UNSPEC, name, NULL,
3304 					   &sa);
3305 	if (ret < 0)
3306 		pr_err("invalid initiator port ID %s\n", name);
3307 	return ret;
3308 }
3309 
3310 static ssize_t srpt_tpg_attrib_srp_max_rdma_size_show(struct config_item *item,
3311 		char *page)
3312 {
3313 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
3314 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
3315 
3316 	return sprintf(page, "%u\n", sport->port_attrib.srp_max_rdma_size);
3317 }
3318 
3319 static ssize_t srpt_tpg_attrib_srp_max_rdma_size_store(struct config_item *item,
3320 		const char *page, size_t count)
3321 {
3322 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
3323 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
3324 	unsigned long val;
3325 	int ret;
3326 
3327 	ret = kstrtoul(page, 0, &val);
3328 	if (ret < 0) {
3329 		pr_err("kstrtoul() failed with ret: %d\n", ret);
3330 		return -EINVAL;
3331 	}
3332 	if (val > MAX_SRPT_RDMA_SIZE) {
3333 		pr_err("val: %lu exceeds MAX_SRPT_RDMA_SIZE: %d\n", val,
3334 			MAX_SRPT_RDMA_SIZE);
3335 		return -EINVAL;
3336 	}
3337 	if (val < DEFAULT_MAX_RDMA_SIZE) {
3338 		pr_err("val: %lu smaller than DEFAULT_MAX_RDMA_SIZE: %d\n",
3339 			val, DEFAULT_MAX_RDMA_SIZE);
3340 		return -EINVAL;
3341 	}
3342 	sport->port_attrib.srp_max_rdma_size = val;
3343 
3344 	return count;
3345 }
3346 
3347 static ssize_t srpt_tpg_attrib_srp_max_rsp_size_show(struct config_item *item,
3348 		char *page)
3349 {
3350 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
3351 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
3352 
3353 	return sprintf(page, "%u\n", sport->port_attrib.srp_max_rsp_size);
3354 }
3355 
3356 static ssize_t srpt_tpg_attrib_srp_max_rsp_size_store(struct config_item *item,
3357 		const char *page, size_t count)
3358 {
3359 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
3360 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
3361 	unsigned long val;
3362 	int ret;
3363 
3364 	ret = kstrtoul(page, 0, &val);
3365 	if (ret < 0) {
3366 		pr_err("kstrtoul() failed with ret: %d\n", ret);
3367 		return -EINVAL;
3368 	}
3369 	if (val > MAX_SRPT_RSP_SIZE) {
3370 		pr_err("val: %lu exceeds MAX_SRPT_RSP_SIZE: %d\n", val,
3371 			MAX_SRPT_RSP_SIZE);
3372 		return -EINVAL;
3373 	}
3374 	if (val < MIN_MAX_RSP_SIZE) {
3375 		pr_err("val: %lu smaller than MIN_MAX_RSP_SIZE: %d\n", val,
3376 			MIN_MAX_RSP_SIZE);
3377 		return -EINVAL;
3378 	}
3379 	sport->port_attrib.srp_max_rsp_size = val;
3380 
3381 	return count;
3382 }
3383 
3384 static ssize_t srpt_tpg_attrib_srp_sq_size_show(struct config_item *item,
3385 		char *page)
3386 {
3387 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
3388 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
3389 
3390 	return sprintf(page, "%u\n", sport->port_attrib.srp_sq_size);
3391 }
3392 
3393 static ssize_t srpt_tpg_attrib_srp_sq_size_store(struct config_item *item,
3394 		const char *page, size_t count)
3395 {
3396 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
3397 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
3398 	unsigned long val;
3399 	int ret;
3400 
3401 	ret = kstrtoul(page, 0, &val);
3402 	if (ret < 0) {
3403 		pr_err("kstrtoul() failed with ret: %d\n", ret);
3404 		return -EINVAL;
3405 	}
3406 	if (val > MAX_SRPT_SRQ_SIZE) {
3407 		pr_err("val: %lu exceeds MAX_SRPT_SRQ_SIZE: %d\n", val,
3408 			MAX_SRPT_SRQ_SIZE);
3409 		return -EINVAL;
3410 	}
3411 	if (val < MIN_SRPT_SRQ_SIZE) {
3412 		pr_err("val: %lu smaller than MIN_SRPT_SRQ_SIZE: %d\n", val,
3413 			MIN_SRPT_SRQ_SIZE);
3414 		return -EINVAL;
3415 	}
3416 	sport->port_attrib.srp_sq_size = val;
3417 
3418 	return count;
3419 }
3420 
3421 static ssize_t srpt_tpg_attrib_use_srq_show(struct config_item *item,
3422 					    char *page)
3423 {
3424 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
3425 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
3426 
3427 	return sprintf(page, "%d\n", sport->port_attrib.use_srq);
3428 }
3429 
3430 static ssize_t srpt_tpg_attrib_use_srq_store(struct config_item *item,
3431 					     const char *page, size_t count)
3432 {
3433 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
3434 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
3435 	struct srpt_device *sdev = sport->sdev;
3436 	unsigned long val;
3437 	bool enabled;
3438 	int ret;
3439 
3440 	ret = kstrtoul(page, 0, &val);
3441 	if (ret < 0)
3442 		return ret;
3443 	if (val != !!val)
3444 		return -EINVAL;
3445 
3446 	ret = mutex_lock_interruptible(&sdev->sdev_mutex);
3447 	if (ret < 0)
3448 		return ret;
3449 	ret = mutex_lock_interruptible(&sport->mutex);
3450 	if (ret < 0)
3451 		goto unlock_sdev;
3452 	enabled = sport->enabled;
3453 	/* Log out all initiator systems before changing 'use_srq'. */
3454 	srpt_set_enabled(sport, false);
3455 	sport->port_attrib.use_srq = val;
3456 	srpt_use_srq(sdev, sport->port_attrib.use_srq);
3457 	srpt_set_enabled(sport, enabled);
3458 	ret = count;
3459 	mutex_unlock(&sport->mutex);
3460 unlock_sdev:
3461 	mutex_unlock(&sdev->sdev_mutex);
3462 
3463 	return ret;
3464 }
3465 
3466 CONFIGFS_ATTR(srpt_tpg_attrib_,  srp_max_rdma_size);
3467 CONFIGFS_ATTR(srpt_tpg_attrib_,  srp_max_rsp_size);
3468 CONFIGFS_ATTR(srpt_tpg_attrib_,  srp_sq_size);
3469 CONFIGFS_ATTR(srpt_tpg_attrib_,  use_srq);
3470 
3471 static struct configfs_attribute *srpt_tpg_attrib_attrs[] = {
3472 	&srpt_tpg_attrib_attr_srp_max_rdma_size,
3473 	&srpt_tpg_attrib_attr_srp_max_rsp_size,
3474 	&srpt_tpg_attrib_attr_srp_sq_size,
3475 	&srpt_tpg_attrib_attr_use_srq,
3476 	NULL,
3477 };
3478 
3479 static struct rdma_cm_id *srpt_create_rdma_id(struct sockaddr *listen_addr)
3480 {
3481 	struct rdma_cm_id *rdma_cm_id;
3482 	int ret;
3483 
3484 	rdma_cm_id = rdma_create_id(&init_net, srpt_rdma_cm_handler,
3485 				    NULL, RDMA_PS_TCP, IB_QPT_RC);
3486 	if (IS_ERR(rdma_cm_id)) {
3487 		pr_err("RDMA/CM ID creation failed: %ld\n",
3488 		       PTR_ERR(rdma_cm_id));
3489 		goto out;
3490 	}
3491 
3492 	ret = rdma_bind_addr(rdma_cm_id, listen_addr);
3493 	if (ret) {
3494 		char addr_str[64];
3495 
3496 		snprintf(addr_str, sizeof(addr_str), "%pISp", listen_addr);
3497 		pr_err("Binding RDMA/CM ID to address %s failed: %d\n",
3498 		       addr_str, ret);
3499 		rdma_destroy_id(rdma_cm_id);
3500 		rdma_cm_id = ERR_PTR(ret);
3501 		goto out;
3502 	}
3503 
3504 	ret = rdma_listen(rdma_cm_id, 128);
3505 	if (ret) {
3506 		pr_err("rdma_listen() failed: %d\n", ret);
3507 		rdma_destroy_id(rdma_cm_id);
3508 		rdma_cm_id = ERR_PTR(ret);
3509 	}
3510 
3511 out:
3512 	return rdma_cm_id;
3513 }
3514 
3515 static ssize_t srpt_rdma_cm_port_show(struct config_item *item, char *page)
3516 {
3517 	return sprintf(page, "%d\n", rdma_cm_port);
3518 }
3519 
3520 static ssize_t srpt_rdma_cm_port_store(struct config_item *item,
3521 				       const char *page, size_t count)
3522 {
3523 	struct sockaddr_in  addr4 = { .sin_family  = AF_INET  };
3524 	struct sockaddr_in6 addr6 = { .sin6_family = AF_INET6 };
3525 	struct rdma_cm_id *new_id = NULL;
3526 	u16 val;
3527 	int ret;
3528 
3529 	ret = kstrtou16(page, 0, &val);
3530 	if (ret < 0)
3531 		return ret;
3532 	ret = count;
3533 	if (rdma_cm_port == val)
3534 		goto out;
3535 
3536 	if (val) {
3537 		addr6.sin6_port = cpu_to_be16(val);
3538 		new_id = srpt_create_rdma_id((struct sockaddr *)&addr6);
3539 		if (IS_ERR(new_id)) {
3540 			addr4.sin_port = cpu_to_be16(val);
3541 			new_id = srpt_create_rdma_id((struct sockaddr *)&addr4);
3542 			if (IS_ERR(new_id)) {
3543 				ret = PTR_ERR(new_id);
3544 				goto out;
3545 			}
3546 		}
3547 	}
3548 
3549 	mutex_lock(&rdma_cm_mutex);
3550 	rdma_cm_port = val;
3551 	swap(rdma_cm_id, new_id);
3552 	mutex_unlock(&rdma_cm_mutex);
3553 
3554 	if (new_id)
3555 		rdma_destroy_id(new_id);
3556 	ret = count;
3557 out:
3558 	return ret;
3559 }
3560 
3561 CONFIGFS_ATTR(srpt_, rdma_cm_port);
3562 
3563 static struct configfs_attribute *srpt_da_attrs[] = {
3564 	&srpt_attr_rdma_cm_port,
3565 	NULL,
3566 };
3567 
3568 static ssize_t srpt_tpg_enable_show(struct config_item *item, char *page)
3569 {
3570 	struct se_portal_group *se_tpg = to_tpg(item);
3571 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
3572 
3573 	return snprintf(page, PAGE_SIZE, "%d\n", (sport->enabled) ? 1: 0);
3574 }
3575 
3576 static ssize_t srpt_tpg_enable_store(struct config_item *item,
3577 		const char *page, size_t count)
3578 {
3579 	struct se_portal_group *se_tpg = to_tpg(item);
3580 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
3581 	unsigned long tmp;
3582         int ret;
3583 
3584 	ret = kstrtoul(page, 0, &tmp);
3585 	if (ret < 0) {
3586 		pr_err("Unable to extract srpt_tpg_store_enable\n");
3587 		return -EINVAL;
3588 	}
3589 
3590 	if ((tmp != 0) && (tmp != 1)) {
3591 		pr_err("Illegal value for srpt_tpg_store_enable: %lu\n", tmp);
3592 		return -EINVAL;
3593 	}
3594 
3595 	mutex_lock(&sport->mutex);
3596 	srpt_set_enabled(sport, tmp);
3597 	mutex_unlock(&sport->mutex);
3598 
3599 	return count;
3600 }
3601 
3602 CONFIGFS_ATTR(srpt_tpg_, enable);
3603 
3604 static struct configfs_attribute *srpt_tpg_attrs[] = {
3605 	&srpt_tpg_attr_enable,
3606 	NULL,
3607 };
3608 
3609 /**
3610  * srpt_make_tpg - configfs callback invoked for mkdir /sys/kernel/config/target/$driver/$port/$tpg
3611  * @wwn: Corresponds to $driver/$port.
3612  * @name: $tpg.
3613  */
3614 static struct se_portal_group *srpt_make_tpg(struct se_wwn *wwn,
3615 					     const char *name)
3616 {
3617 	struct srpt_port *sport = wwn->priv;
3618 	static struct se_portal_group *tpg;
3619 	int res;
3620 
3621 	WARN_ON_ONCE(wwn != &sport->port_guid_wwn &&
3622 		     wwn != &sport->port_gid_wwn);
3623 	tpg = wwn == &sport->port_guid_wwn ? &sport->port_guid_tpg :
3624 		&sport->port_gid_tpg;
3625 	res = core_tpg_register(wwn, tpg, SCSI_PROTOCOL_SRP);
3626 	if (res)
3627 		return ERR_PTR(res);
3628 
3629 	return tpg;
3630 }
3631 
3632 /**
3633  * srpt_drop_tpg - configfs callback invoked for rmdir /sys/kernel/config/target/$driver/$port/$tpg
3634  * @tpg: Target portal group to deregister.
3635  */
3636 static void srpt_drop_tpg(struct se_portal_group *tpg)
3637 {
3638 	struct srpt_port *sport = srpt_tpg_to_sport(tpg);
3639 
3640 	sport->enabled = false;
3641 	core_tpg_deregister(tpg);
3642 }
3643 
3644 /**
3645  * srpt_make_tport - configfs callback invoked for mkdir /sys/kernel/config/target/$driver/$port
3646  * @tf: Not used.
3647  * @group: Not used.
3648  * @name: $port.
3649  */
3650 static struct se_wwn *srpt_make_tport(struct target_fabric_configfs *tf,
3651 				      struct config_group *group,
3652 				      const char *name)
3653 {
3654 	return srpt_lookup_wwn(name) ? : ERR_PTR(-EINVAL);
3655 }
3656 
3657 /**
3658  * srpt_drop_tport - configfs callback invoked for rmdir /sys/kernel/config/target/$driver/$port
3659  * @wwn: $port.
3660  */
3661 static void srpt_drop_tport(struct se_wwn *wwn)
3662 {
3663 }
3664 
3665 static ssize_t srpt_wwn_version_show(struct config_item *item, char *buf)
3666 {
3667 	return scnprintf(buf, PAGE_SIZE, "%s\n", DRV_VERSION);
3668 }
3669 
3670 CONFIGFS_ATTR_RO(srpt_wwn_, version);
3671 
3672 static struct configfs_attribute *srpt_wwn_attrs[] = {
3673 	&srpt_wwn_attr_version,
3674 	NULL,
3675 };
3676 
3677 static const struct target_core_fabric_ops srpt_template = {
3678 	.module				= THIS_MODULE,
3679 	.name				= "srpt",
3680 	.get_fabric_name		= srpt_get_fabric_name,
3681 	.tpg_get_wwn			= srpt_get_fabric_wwn,
3682 	.tpg_get_tag			= srpt_get_tag,
3683 	.tpg_check_demo_mode		= srpt_check_false,
3684 	.tpg_check_demo_mode_cache	= srpt_check_true,
3685 	.tpg_check_demo_mode_write_protect = srpt_check_true,
3686 	.tpg_check_prod_mode_write_protect = srpt_check_false,
3687 	.tpg_get_inst_index		= srpt_tpg_get_inst_index,
3688 	.release_cmd			= srpt_release_cmd,
3689 	.check_stop_free		= srpt_check_stop_free,
3690 	.close_session			= srpt_close_session,
3691 	.sess_get_index			= srpt_sess_get_index,
3692 	.sess_get_initiator_sid		= NULL,
3693 	.write_pending			= srpt_write_pending,
3694 	.write_pending_status		= srpt_write_pending_status,
3695 	.set_default_node_attributes	= srpt_set_default_node_attrs,
3696 	.get_cmd_state			= srpt_get_tcm_cmd_state,
3697 	.queue_data_in			= srpt_queue_data_in,
3698 	.queue_status			= srpt_queue_status,
3699 	.queue_tm_rsp			= srpt_queue_tm_rsp,
3700 	.aborted_task			= srpt_aborted_task,
3701 	/*
3702 	 * Setup function pointers for generic logic in
3703 	 * target_core_fabric_configfs.c
3704 	 */
3705 	.fabric_make_wwn		= srpt_make_tport,
3706 	.fabric_drop_wwn		= srpt_drop_tport,
3707 	.fabric_make_tpg		= srpt_make_tpg,
3708 	.fabric_drop_tpg		= srpt_drop_tpg,
3709 	.fabric_init_nodeacl		= srpt_init_nodeacl,
3710 
3711 	.tfc_discovery_attrs		= srpt_da_attrs,
3712 	.tfc_wwn_attrs			= srpt_wwn_attrs,
3713 	.tfc_tpg_base_attrs		= srpt_tpg_attrs,
3714 	.tfc_tpg_attrib_attrs		= srpt_tpg_attrib_attrs,
3715 };
3716 
3717 /**
3718  * srpt_init_module - kernel module initialization
3719  *
3720  * Note: Since ib_register_client() registers callback functions, and since at
3721  * least one of these callback functions (srpt_add_one()) calls target core
3722  * functions, this driver must be registered with the target core before
3723  * ib_register_client() is called.
3724  */
3725 static int __init srpt_init_module(void)
3726 {
3727 	int ret;
3728 
3729 	ret = -EINVAL;
3730 	if (srp_max_req_size < MIN_MAX_REQ_SIZE) {
3731 		pr_err("invalid value %d for kernel module parameter"
3732 		       " srp_max_req_size -- must be at least %d.\n",
3733 		       srp_max_req_size, MIN_MAX_REQ_SIZE);
3734 		goto out;
3735 	}
3736 
3737 	if (srpt_srq_size < MIN_SRPT_SRQ_SIZE
3738 	    || srpt_srq_size > MAX_SRPT_SRQ_SIZE) {
3739 		pr_err("invalid value %d for kernel module parameter"
3740 		       " srpt_srq_size -- must be in the range [%d..%d].\n",
3741 		       srpt_srq_size, MIN_SRPT_SRQ_SIZE, MAX_SRPT_SRQ_SIZE);
3742 		goto out;
3743 	}
3744 
3745 	ret = target_register_template(&srpt_template);
3746 	if (ret)
3747 		goto out;
3748 
3749 	ret = ib_register_client(&srpt_client);
3750 	if (ret) {
3751 		pr_err("couldn't register IB client\n");
3752 		goto out_unregister_target;
3753 	}
3754 
3755 	return 0;
3756 
3757 out_unregister_target:
3758 	target_unregister_template(&srpt_template);
3759 out:
3760 	return ret;
3761 }
3762 
3763 static void __exit srpt_cleanup_module(void)
3764 {
3765 	if (rdma_cm_id)
3766 		rdma_destroy_id(rdma_cm_id);
3767 	ib_unregister_client(&srpt_client);
3768 	target_unregister_template(&srpt_template);
3769 }
3770 
3771 module_init(srpt_init_module);
3772 module_exit(srpt_cleanup_module);
3773