xref: /linux/drivers/infiniband/ulp/srpt/ib_srpt.c (revision 3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d)
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/hex.h>
37 #include <linux/init.h>
38 #include <linux/slab.h>
39 #include <linux/err.h>
40 #include <linux/ctype.h>
41 #include <linux/kthread.h>
42 #include <linux/string.h>
43 #include <linux/delay.h>
44 #include <linux/atomic.h>
45 #include <linux/inet.h>
46 #include <rdma/ib_cache.h>
47 #include <scsi/scsi_proto.h>
48 #include <scsi/scsi_tcq.h>
49 #include <target/target_core_base.h>
50 #include <target/target_core_fabric.h>
51 #include "ib_srpt.h"
52 
53 /* Name of this kernel module. */
54 #define DRV_NAME		"ib_srpt"
55 
56 #define SRPT_ID_STRING	"Linux SRP target"
57 
58 #undef pr_fmt
59 #define pr_fmt(fmt) DRV_NAME " " fmt
60 
61 MODULE_AUTHOR("Vu Pham and Bart Van Assche");
62 MODULE_DESCRIPTION("SCSI RDMA Protocol target driver");
63 MODULE_LICENSE("Dual BSD/GPL");
64 
65 /*
66  * Global Variables
67  */
68 
69 static u64 srpt_service_guid;
70 static DEFINE_SPINLOCK(srpt_dev_lock);	/* Protects srpt_dev_list. */
71 static LIST_HEAD(srpt_dev_list);	/* List of srpt_device structures. */
72 static DEFINE_MUTEX(srpt_mc_mutex);	/* Protects srpt_memory_caches. */
73 static DEFINE_XARRAY(srpt_memory_caches); /* See also srpt_memory_cache_entry */
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 unsigned int srpt_srq_size = DEFAULT_SRPT_SRQ_SIZE;
81 module_param(srpt_srq_size, uint, 0444);
82 MODULE_PARM_DESC(srpt_srq_size,
83 		 "Shared receive queue (SRQ) size.");
84 
85 static int srpt_set_u64_x(const char *buffer, const struct kernel_param *kp)
86 {
87 	return kstrtou64(buffer, 16, (u64 *)kp->arg);
88 }
89 static int srpt_get_u64_x(char *buffer, const struct kernel_param *kp)
90 {
91 	return sprintf(buffer, "0x%016llx\n", *(u64 *)kp->arg);
92 }
93 module_param_call(srpt_service_guid, srpt_set_u64_x, srpt_get_u64_x,
94 		  &srpt_service_guid, 0444);
95 MODULE_PARM_DESC(srpt_service_guid,
96 		 "Using this value for ioc_guid, id_ext, and cm_listen_id instead of using the node_guid of the first HCA.");
97 
98 static struct ib_client srpt_client;
99 /* Protects both rdma_cm_port and rdma_cm_id. */
100 static DEFINE_MUTEX(rdma_cm_mutex);
101 /* Port number RDMA/CM will bind to. */
102 static u16 rdma_cm_port;
103 static struct rdma_cm_id *rdma_cm_id;
104 static void srpt_release_cmd(struct se_cmd *se_cmd);
105 static void srpt_free_ch(struct kref *kref);
106 static int srpt_queue_status(struct se_cmd *cmd);
107 static void srpt_recv_done(struct ib_cq *cq, struct ib_wc *wc);
108 static void srpt_send_done(struct ib_cq *cq, struct ib_wc *wc);
109 static void srpt_process_wait_list(struct srpt_rdma_ch *ch);
110 
111 /* Type of the entries in srpt_memory_caches. */
112 struct srpt_memory_cache_entry {
113 	refcount_t ref;
114 	struct kmem_cache *c;
115 };
116 
117 static struct kmem_cache *srpt_cache_get(unsigned int object_size)
118 {
119 	struct srpt_memory_cache_entry *e;
120 	char name[32];
121 	void *res;
122 
123 	guard(mutex)(&srpt_mc_mutex);
124 	e = xa_load(&srpt_memory_caches, object_size);
125 	if (e) {
126 		refcount_inc(&e->ref);
127 		return e->c;
128 	}
129 	snprintf(name, sizeof(name), "srpt-%u", object_size);
130 	e = kmalloc_obj(*e);
131 	if (!e)
132 		return NULL;
133 	refcount_set(&e->ref, 1);
134 	e->c = kmem_cache_create(name, object_size, /*align=*/512, 0, NULL);
135 	if (!e->c)
136 		goto free_entry;
137 	res = xa_store(&srpt_memory_caches, object_size, e, GFP_KERNEL);
138 	if (xa_is_err(res))
139 		goto destroy_cache;
140 	return e->c;
141 
142 destroy_cache:
143 	kmem_cache_destroy(e->c);
144 
145 free_entry:
146 	kfree(e);
147 	return NULL;
148 }
149 
150 static void srpt_cache_put(struct kmem_cache *c)
151 {
152 	struct srpt_memory_cache_entry *e = NULL;
153 	unsigned long object_size;
154 
155 	guard(mutex)(&srpt_mc_mutex);
156 	xa_for_each(&srpt_memory_caches, object_size, e)
157 		if (e->c == c)
158 			break;
159 	if (WARN_ON_ONCE(!e))
160 		return;
161 	if (!refcount_dec_and_test(&e->ref))
162 		return;
163 	WARN_ON_ONCE(xa_erase(&srpt_memory_caches, object_size) != e);
164 	kmem_cache_destroy(e->c);
165 	kfree(e);
166 }
167 
168 /*
169  * The only allowed channel state changes are those that change the channel
170  * state into a state with a higher numerical value. Hence the new > prev test.
171  */
172 static bool srpt_set_ch_state(struct srpt_rdma_ch *ch, enum rdma_ch_state new)
173 {
174 	unsigned long flags;
175 	enum rdma_ch_state prev;
176 	bool changed = false;
177 
178 	spin_lock_irqsave(&ch->spinlock, flags);
179 	prev = ch->state;
180 	if (new > prev) {
181 		ch->state = new;
182 		changed = true;
183 	}
184 	spin_unlock_irqrestore(&ch->spinlock, flags);
185 
186 	return changed;
187 }
188 
189 /**
190  * srpt_event_handler - asynchronous IB event callback function
191  * @handler: IB event handler registered by ib_register_event_handler().
192  * @event: Description of the event that occurred.
193  *
194  * Callback function called by the InfiniBand core when an asynchronous IB
195  * event occurs. This callback may occur in interrupt context. See also
196  * section 11.5.2, Set Asynchronous Event Handler in the InfiniBand
197  * Architecture Specification.
198  */
199 static void srpt_event_handler(struct ib_event_handler *handler,
200 			       struct ib_event *event)
201 {
202 	struct srpt_device *sdev =
203 		container_of(handler, struct srpt_device, event_handler);
204 	struct srpt_port *sport;
205 	u8 port_num;
206 
207 	pr_debug("ASYNC event= %d on device= %s\n", event->event,
208 		 dev_name(&sdev->device->dev));
209 
210 	switch (event->event) {
211 	case IB_EVENT_PORT_ERR:
212 		port_num = event->element.port_num - 1;
213 		if (port_num < sdev->device->phys_port_cnt) {
214 			sport = &sdev->port[port_num];
215 			sport->lid = 0;
216 			sport->sm_lid = 0;
217 		} else {
218 			WARN(true, "event %d: port_num %d out of range 1..%d\n",
219 			     event->event, port_num + 1,
220 			     sdev->device->phys_port_cnt);
221 		}
222 		break;
223 	case IB_EVENT_PORT_ACTIVE:
224 	case IB_EVENT_LID_CHANGE:
225 	case IB_EVENT_PKEY_CHANGE:
226 	case IB_EVENT_SM_CHANGE:
227 	case IB_EVENT_CLIENT_REREGISTER:
228 	case IB_EVENT_GID_CHANGE:
229 		/* Refresh port data asynchronously. */
230 		port_num = event->element.port_num - 1;
231 		if (port_num < sdev->device->phys_port_cnt) {
232 			sport = &sdev->port[port_num];
233 			if (!sport->lid && !sport->sm_lid)
234 				schedule_work(&sport->work);
235 		} else {
236 			WARN(true, "event %d: port_num %d out of range 1..%d\n",
237 			     event->event, port_num + 1,
238 			     sdev->device->phys_port_cnt);
239 		}
240 		break;
241 	default:
242 		pr_err("received unrecognized IB event %d\n", event->event);
243 		break;
244 	}
245 }
246 
247 /**
248  * srpt_srq_event - SRQ event callback function
249  * @event: Description of the event that occurred.
250  * @ctx: Context pointer specified at SRQ creation time.
251  */
252 static void srpt_srq_event(struct ib_event *event, void *ctx)
253 {
254 	pr_debug("SRQ event %d\n", event->event);
255 }
256 
257 static const char *get_ch_state_name(enum rdma_ch_state s)
258 {
259 	switch (s) {
260 	case CH_CONNECTING:
261 		return "connecting";
262 	case CH_LIVE:
263 		return "live";
264 	case CH_DISCONNECTING:
265 		return "disconnecting";
266 	case CH_DRAINING:
267 		return "draining";
268 	case CH_DISCONNECTED:
269 		return "disconnected";
270 	}
271 	return "???";
272 }
273 
274 /**
275  * srpt_qp_event - QP event callback function
276  * @event: Description of the event that occurred.
277  * @ptr: SRPT RDMA channel.
278  */
279 static void srpt_qp_event(struct ib_event *event, void *ptr)
280 {
281 	struct srpt_rdma_ch *ch = ptr;
282 
283 	pr_debug("QP event %d on ch=%p sess_name=%s-%d state=%s\n",
284 		 event->event, ch, ch->sess_name, ch->qp->qp_num,
285 		 get_ch_state_name(ch->state));
286 
287 	switch (event->event) {
288 	case IB_EVENT_COMM_EST:
289 		if (ch->using_rdma_cm)
290 			rdma_notify(ch->rdma_cm.cm_id, event->event);
291 		else
292 			ib_cm_notify(ch->ib_cm.cm_id, event->event);
293 		break;
294 	case IB_EVENT_QP_LAST_WQE_REACHED:
295 		pr_debug("%s-%d, state %s: received Last WQE event.\n",
296 			 ch->sess_name, ch->qp->qp_num,
297 			 get_ch_state_name(ch->state));
298 		break;
299 	default:
300 		pr_err("received unrecognized IB QP event %d\n", event->event);
301 		break;
302 	}
303 }
304 
305 /**
306  * srpt_set_ioc - initialize a IOUnitInfo structure
307  * @c_list: controller list.
308  * @slot: one-based slot number.
309  * @value: four-bit value.
310  *
311  * Copies the lowest four bits of value in element slot of the array of four
312  * bit elements called c_list (controller list). The index slot is one-based.
313  */
314 static void srpt_set_ioc(u8 *c_list, u32 slot, u8 value)
315 {
316 	u16 id;
317 	u8 tmp;
318 
319 	id = (slot - 1) / 2;
320 	if (slot & 0x1) {
321 		tmp = c_list[id] & 0xf;
322 		c_list[id] = (value << 4) | tmp;
323 	} else {
324 		tmp = c_list[id] & 0xf0;
325 		c_list[id] = (value & 0xf) | tmp;
326 	}
327 }
328 
329 /**
330  * srpt_get_class_port_info - copy ClassPortInfo to a management datagram
331  * @mad: Datagram that will be sent as response to DM_ATTR_CLASS_PORT_INFO.
332  *
333  * See also section 16.3.3.1 ClassPortInfo in the InfiniBand Architecture
334  * Specification.
335  */
336 static void srpt_get_class_port_info(struct ib_dm_mad *mad)
337 {
338 	struct ib_class_port_info *cif;
339 
340 	cif = (struct ib_class_port_info *)mad->data;
341 	memset(cif, 0, sizeof(*cif));
342 	cif->base_version = 1;
343 	cif->class_version = 1;
344 
345 	ib_set_cpi_resp_time(cif, 20);
346 	mad->mad_hdr.status = 0;
347 }
348 
349 /**
350  * srpt_get_iou - write IOUnitInfo to a management datagram
351  * @mad: Datagram that will be sent as response to DM_ATTR_IOU_INFO.
352  *
353  * See also section 16.3.3.3 IOUnitInfo in the InfiniBand Architecture
354  * Specification. See also section B.7, table B.6 in the SRP r16a document.
355  */
356 static void srpt_get_iou(struct ib_dm_mad *mad)
357 {
358 	struct ib_dm_iou_info *ioui;
359 	u8 slot;
360 	int i;
361 
362 	ioui = (struct ib_dm_iou_info *)mad->data;
363 	ioui->change_id = cpu_to_be16(1);
364 	ioui->max_controllers = 16;
365 
366 	/* set present for slot 1 and empty for the rest */
367 	srpt_set_ioc(ioui->controller_list, 1, 1);
368 	for (i = 1, slot = 2; i < 16; i++, slot++)
369 		srpt_set_ioc(ioui->controller_list, slot, 0);
370 
371 	mad->mad_hdr.status = 0;
372 }
373 
374 /**
375  * srpt_get_ioc - write IOControllerprofile to a management datagram
376  * @sport: HCA port through which the MAD has been received.
377  * @slot: Slot number specified in DM_ATTR_IOC_PROFILE query.
378  * @mad: Datagram that will be sent as response to DM_ATTR_IOC_PROFILE.
379  *
380  * See also section 16.3.3.4 IOControllerProfile in the InfiniBand
381  * Architecture Specification. See also section B.7, table B.7 in the SRP
382  * r16a document.
383  */
384 static void srpt_get_ioc(struct srpt_port *sport, u32 slot,
385 			 struct ib_dm_mad *mad)
386 {
387 	struct srpt_device *sdev = sport->sdev;
388 	struct ib_dm_ioc_profile *iocp;
389 	int send_queue_depth;
390 
391 	iocp = (struct ib_dm_ioc_profile *)mad->data;
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) {
400 		mad->mad_hdr.status
401 			= cpu_to_be16(DM_MAD_STATUS_NO_IOC);
402 		return;
403 	}
404 
405 	if (sdev->use_srq)
406 		send_queue_depth = sdev->srq_size;
407 	else
408 		send_queue_depth = min(sdev->device->attrs.max_qp_wr, MAX_SRPT_RQ_SIZE);
409 
410 	memset(iocp, 0, sizeof(*iocp));
411 	strcpy(iocp->id_string, SRPT_ID_STRING);
412 	iocp->guid = cpu_to_be64(srpt_service_guid);
413 	iocp->vendor_id = cpu_to_be32(sdev->device->attrs.vendor_id);
414 	iocp->device_id = cpu_to_be32(sdev->device->attrs.vendor_part_id);
415 	iocp->device_version = cpu_to_be16(sdev->device->attrs.hw_ver);
416 	iocp->subsys_vendor_id = cpu_to_be32(sdev->device->attrs.vendor_id);
417 	iocp->subsys_device_id = 0x0;
418 	iocp->io_class = cpu_to_be16(SRP_REV16A_IB_IO_CLASS);
419 	iocp->io_subclass = cpu_to_be16(SRP_IO_SUBCLASS);
420 	iocp->protocol = cpu_to_be16(SRP_PROTOCOL);
421 	iocp->protocol_version = cpu_to_be16(SRP_PROTOCOL_VERSION);
422 	iocp->send_queue_depth = cpu_to_be16(send_queue_depth);
423 	iocp->rdma_read_depth = 4;
424 	iocp->send_size = cpu_to_be32(srp_max_req_size);
425 	iocp->rdma_size = cpu_to_be32(min(sport->port_attrib.srp_max_rdma_size,
426 					  1U << 24));
427 	iocp->num_svc_entries = 1;
428 	iocp->op_cap_mask = SRP_SEND_TO_IOC | SRP_SEND_FROM_IOC |
429 		SRP_RDMA_READ_FROM_IOC | SRP_RDMA_WRITE_FROM_IOC;
430 
431 	mad->mad_hdr.status = 0;
432 }
433 
434 /**
435  * srpt_get_svc_entries - write ServiceEntries to a management datagram
436  * @ioc_guid: I/O controller GUID to use in reply.
437  * @slot: I/O controller number.
438  * @hi: End of the range of service entries to be specified in the reply.
439  * @lo: Start of the range of service entries to be specified in the reply..
440  * @mad: Datagram that will be sent as response to DM_ATTR_SVC_ENTRIES.
441  *
442  * See also section 16.3.3.5 ServiceEntries in the InfiniBand Architecture
443  * Specification. See also section B.7, table B.8 in the SRP r16a document.
444  */
445 static void srpt_get_svc_entries(u64 ioc_guid,
446 				 u16 slot, u8 hi, u8 lo, struct ib_dm_mad *mad)
447 {
448 	struct ib_dm_svc_entries *svc_entries;
449 
450 	WARN_ON(!ioc_guid);
451 
452 	if (!slot || slot > 16) {
453 		mad->mad_hdr.status
454 			= cpu_to_be16(DM_MAD_STATUS_INVALID_FIELD);
455 		return;
456 	}
457 
458 	if (slot > 2 || lo > hi || hi > 1) {
459 		mad->mad_hdr.status
460 			= cpu_to_be16(DM_MAD_STATUS_NO_IOC);
461 		return;
462 	}
463 
464 	svc_entries = (struct ib_dm_svc_entries *)mad->data;
465 	memset(svc_entries, 0, sizeof(*svc_entries));
466 	svc_entries->service_entries[0].id = cpu_to_be64(ioc_guid);
467 	snprintf(svc_entries->service_entries[0].name,
468 		 sizeof(svc_entries->service_entries[0].name),
469 		 "%s%016llx",
470 		 SRP_SERVICE_NAME_PREFIX,
471 		 ioc_guid);
472 
473 	mad->mad_hdr.status = 0;
474 }
475 
476 /**
477  * srpt_mgmt_method_get - process a received management datagram
478  * @sp:      HCA port through which the MAD has been received.
479  * @rq_mad:  received MAD.
480  * @rsp_mad: response MAD.
481  */
482 static void srpt_mgmt_method_get(struct srpt_port *sp, struct ib_mad *rq_mad,
483 				 struct ib_dm_mad *rsp_mad)
484 {
485 	u16 attr_id;
486 	u32 slot;
487 	u8 hi, lo;
488 
489 	attr_id = be16_to_cpu(rq_mad->mad_hdr.attr_id);
490 	switch (attr_id) {
491 	case DM_ATTR_CLASS_PORT_INFO:
492 		srpt_get_class_port_info(rsp_mad);
493 		break;
494 	case DM_ATTR_IOU_INFO:
495 		srpt_get_iou(rsp_mad);
496 		break;
497 	case DM_ATTR_IOC_PROFILE:
498 		slot = be32_to_cpu(rq_mad->mad_hdr.attr_mod);
499 		srpt_get_ioc(sp, slot, rsp_mad);
500 		break;
501 	case DM_ATTR_SVC_ENTRIES:
502 		slot = be32_to_cpu(rq_mad->mad_hdr.attr_mod);
503 		hi = (u8) ((slot >> 8) & 0xff);
504 		lo = (u8) (slot & 0xff);
505 		slot = (u16) ((slot >> 16) & 0xffff);
506 		srpt_get_svc_entries(srpt_service_guid,
507 				     slot, hi, lo, rsp_mad);
508 		break;
509 	default:
510 		rsp_mad->mad_hdr.status =
511 		    cpu_to_be16(DM_MAD_STATUS_UNSUP_METHOD_ATTR);
512 		break;
513 	}
514 }
515 
516 /**
517  * srpt_mad_send_handler - MAD send completion callback
518  * @mad_agent: Return value of ib_register_mad_agent().
519  * @mad_wc: Work completion reporting that the MAD has been sent.
520  */
521 static void srpt_mad_send_handler(struct ib_mad_agent *mad_agent,
522 				  struct ib_mad_send_wc *mad_wc)
523 {
524 	rdma_destroy_ah(mad_wc->send_buf->ah, RDMA_DESTROY_AH_SLEEPABLE);
525 	ib_free_send_mad(mad_wc->send_buf);
526 }
527 
528 /**
529  * srpt_mad_recv_handler - MAD reception callback function
530  * @mad_agent: Return value of ib_register_mad_agent().
531  * @send_buf: Not used.
532  * @mad_wc: Work completion reporting that a MAD has been received.
533  */
534 static void srpt_mad_recv_handler(struct ib_mad_agent *mad_agent,
535 				  struct ib_mad_send_buf *send_buf,
536 				  struct ib_mad_recv_wc *mad_wc)
537 {
538 	struct srpt_port *sport = (struct srpt_port *)mad_agent->context;
539 	struct ib_ah *ah;
540 	struct ib_mad_send_buf *rsp;
541 	struct ib_dm_mad *dm_mad;
542 
543 	if (!mad_wc || !mad_wc->recv_buf.mad)
544 		return;
545 
546 	ah = ib_create_ah_from_wc(mad_agent->qp->pd, mad_wc->wc,
547 				  mad_wc->recv_buf.grh, mad_agent->port_num);
548 	if (IS_ERR(ah))
549 		goto err;
550 
551 	BUILD_BUG_ON(offsetof(struct ib_dm_mad, data) != IB_MGMT_DEVICE_HDR);
552 
553 	rsp = ib_create_send_mad(mad_agent, mad_wc->wc->src_qp,
554 				 mad_wc->wc->pkey_index, 0,
555 				 IB_MGMT_DEVICE_HDR, IB_MGMT_DEVICE_DATA,
556 				 GFP_KERNEL,
557 				 IB_MGMT_BASE_VERSION);
558 	if (IS_ERR(rsp))
559 		goto err_rsp;
560 
561 	rsp->ah = ah;
562 
563 	dm_mad = rsp->mad;
564 	memcpy(dm_mad, mad_wc->recv_buf.mad, sizeof(*dm_mad));
565 	dm_mad->mad_hdr.method = IB_MGMT_METHOD_GET_RESP;
566 	dm_mad->mad_hdr.status = 0;
567 
568 	switch (mad_wc->recv_buf.mad->mad_hdr.method) {
569 	case IB_MGMT_METHOD_GET:
570 		srpt_mgmt_method_get(sport, mad_wc->recv_buf.mad, dm_mad);
571 		break;
572 	case IB_MGMT_METHOD_SET:
573 		dm_mad->mad_hdr.status =
574 		    cpu_to_be16(DM_MAD_STATUS_UNSUP_METHOD_ATTR);
575 		break;
576 	default:
577 		dm_mad->mad_hdr.status =
578 		    cpu_to_be16(DM_MAD_STATUS_UNSUP_METHOD);
579 		break;
580 	}
581 
582 	if (!ib_post_send_mad(rsp, NULL)) {
583 		ib_free_recv_mad(mad_wc);
584 		/* will destroy_ah & free_send_mad in send completion */
585 		return;
586 	}
587 
588 	ib_free_send_mad(rsp);
589 
590 err_rsp:
591 	rdma_destroy_ah(ah, RDMA_DESTROY_AH_SLEEPABLE);
592 err:
593 	ib_free_recv_mad(mad_wc);
594 }
595 
596 static int srpt_format_guid(char *buf, unsigned int size, const __be64 *guid)
597 {
598 	const __be16 *g = (const __be16 *)guid;
599 
600 	return snprintf(buf, size, "%04x:%04x:%04x:%04x",
601 			be16_to_cpu(g[0]), be16_to_cpu(g[1]),
602 			be16_to_cpu(g[2]), be16_to_cpu(g[3]));
603 }
604 
605 /**
606  * srpt_refresh_port - configure a HCA port
607  * @sport: SRPT HCA port.
608  *
609  * Enable InfiniBand management datagram processing, update the cached sm_lid,
610  * lid and gid values, and register a callback function for processing MADs
611  * on the specified port.
612  *
613  * Note: It is safe to call this function more than once for the same port.
614  */
615 static int srpt_refresh_port(struct srpt_port *sport)
616 {
617 	struct ib_mad_agent *mad_agent;
618 	struct ib_mad_reg_req reg_req;
619 	struct ib_port_modify port_modify;
620 	struct ib_port_attr port_attr;
621 	int ret;
622 
623 	ret = ib_query_port(sport->sdev->device, sport->port, &port_attr);
624 	if (ret)
625 		return ret;
626 
627 	sport->sm_lid = port_attr.sm_lid;
628 	sport->lid = port_attr.lid;
629 
630 	ret = rdma_query_gid(sport->sdev->device, sport->port, 0, &sport->gid);
631 	if (ret)
632 		return ret;
633 
634 	srpt_format_guid(sport->guid_name, ARRAY_SIZE(sport->guid_name),
635 			 &sport->gid.global.interface_id);
636 	snprintf(sport->gid_name, ARRAY_SIZE(sport->gid_name),
637 		 "0x%016llx%016llx",
638 		 be64_to_cpu(sport->gid.global.subnet_prefix),
639 		 be64_to_cpu(sport->gid.global.interface_id));
640 
641 	if (rdma_protocol_iwarp(sport->sdev->device, sport->port))
642 		return 0;
643 
644 	memset(&port_modify, 0, sizeof(port_modify));
645 	port_modify.set_port_cap_mask = IB_PORT_DEVICE_MGMT_SUP;
646 	port_modify.clr_port_cap_mask = 0;
647 
648 	ret = ib_modify_port(sport->sdev->device, sport->port, 0, &port_modify);
649 	if (ret) {
650 		pr_warn("%s-%d: enabling device management failed (%d). Note: this is expected if SR-IOV is enabled.\n",
651 			dev_name(&sport->sdev->device->dev), sport->port, ret);
652 		return 0;
653 	}
654 
655 	if (!sport->mad_agent) {
656 		memset(&reg_req, 0, sizeof(reg_req));
657 		reg_req.mgmt_class = IB_MGMT_CLASS_DEVICE_MGMT;
658 		reg_req.mgmt_class_version = IB_MGMT_BASE_VERSION;
659 		set_bit(IB_MGMT_METHOD_GET, reg_req.method_mask);
660 		set_bit(IB_MGMT_METHOD_SET, reg_req.method_mask);
661 
662 		mad_agent = ib_register_mad_agent(sport->sdev->device,
663 						  sport->port,
664 						  IB_QPT_GSI,
665 						  &reg_req, 0,
666 						  srpt_mad_send_handler,
667 						  srpt_mad_recv_handler,
668 						  sport, 0);
669 		if (IS_ERR(mad_agent)) {
670 			pr_err("%s-%d: MAD agent registration failed (%pe). Note: this is expected if SR-IOV is enabled.\n",
671 			       dev_name(&sport->sdev->device->dev), sport->port,
672 			       mad_agent);
673 			sport->mad_agent = NULL;
674 			memset(&port_modify, 0, sizeof(port_modify));
675 			port_modify.clr_port_cap_mask = IB_PORT_DEVICE_MGMT_SUP;
676 			ib_modify_port(sport->sdev->device, sport->port, 0,
677 				       &port_modify);
678 			return 0;
679 		}
680 
681 		sport->mad_agent = mad_agent;
682 	}
683 
684 	return 0;
685 }
686 
687 /**
688  * srpt_unregister_mad_agent - unregister MAD callback functions
689  * @sdev: SRPT HCA pointer.
690  * @port_cnt: number of ports with registered MAD
691  *
692  * Note: It is safe to call this function more than once for the same device.
693  */
694 static void srpt_unregister_mad_agent(struct srpt_device *sdev, int port_cnt)
695 {
696 	struct ib_port_modify port_modify = {
697 		.clr_port_cap_mask = IB_PORT_DEVICE_MGMT_SUP,
698 	};
699 	struct srpt_port *sport;
700 	int i;
701 
702 	for (i = 1; i <= port_cnt; i++) {
703 		sport = &sdev->port[i - 1];
704 		WARN_ON(sport->port != i);
705 		if (sport->mad_agent) {
706 			ib_modify_port(sdev->device, i, 0, &port_modify);
707 			ib_unregister_mad_agent(sport->mad_agent);
708 			sport->mad_agent = NULL;
709 		}
710 	}
711 }
712 
713 /**
714  * srpt_alloc_ioctx - allocate a SRPT I/O context structure
715  * @sdev: SRPT HCA pointer.
716  * @ioctx_size: I/O context size.
717  * @buf_cache: I/O buffer cache.
718  * @dir: DMA data direction.
719  */
720 static struct srpt_ioctx *srpt_alloc_ioctx(struct srpt_device *sdev,
721 					   int ioctx_size,
722 					   struct kmem_cache *buf_cache,
723 					   enum dma_data_direction dir)
724 {
725 	struct srpt_ioctx *ioctx;
726 
727 	ioctx = kzalloc(ioctx_size, GFP_KERNEL);
728 	if (!ioctx)
729 		goto err;
730 
731 	ioctx->buf = kmem_cache_alloc(buf_cache, GFP_KERNEL);
732 	if (!ioctx->buf)
733 		goto err_free_ioctx;
734 
735 	ioctx->dma = ib_dma_map_single(sdev->device, ioctx->buf,
736 				       kmem_cache_size(buf_cache), dir);
737 	if (ib_dma_mapping_error(sdev->device, ioctx->dma))
738 		goto err_free_buf;
739 
740 	return ioctx;
741 
742 err_free_buf:
743 	kmem_cache_free(buf_cache, ioctx->buf);
744 err_free_ioctx:
745 	kfree(ioctx);
746 err:
747 	return NULL;
748 }
749 
750 /**
751  * srpt_free_ioctx - free a SRPT I/O context structure
752  * @sdev: SRPT HCA pointer.
753  * @ioctx: I/O context pointer.
754  * @buf_cache: I/O buffer cache.
755  * @dir: DMA data direction.
756  */
757 static void srpt_free_ioctx(struct srpt_device *sdev, struct srpt_ioctx *ioctx,
758 			    struct kmem_cache *buf_cache,
759 			    enum dma_data_direction dir)
760 {
761 	if (!ioctx)
762 		return;
763 
764 	ib_dma_unmap_single(sdev->device, ioctx->dma,
765 			    kmem_cache_size(buf_cache), dir);
766 	kmem_cache_free(buf_cache, ioctx->buf);
767 	kfree(ioctx);
768 }
769 
770 /**
771  * srpt_alloc_ioctx_ring - allocate a ring of SRPT I/O context structures
772  * @sdev:       Device to allocate the I/O context ring for.
773  * @ring_size:  Number of elements in the I/O context ring.
774  * @ioctx_size: I/O context size.
775  * @buf_cache:  I/O buffer cache.
776  * @alignment_offset: Offset in each ring buffer at which the SRP information
777  *		unit starts.
778  * @dir:        DMA data direction.
779  */
780 static struct srpt_ioctx **srpt_alloc_ioctx_ring(struct srpt_device *sdev,
781 				int ring_size, int ioctx_size,
782 				struct kmem_cache *buf_cache,
783 				int alignment_offset,
784 				enum dma_data_direction dir)
785 {
786 	struct srpt_ioctx **ring;
787 	int i;
788 
789 	WARN_ON(ioctx_size != sizeof(struct srpt_recv_ioctx) &&
790 		ioctx_size != sizeof(struct srpt_send_ioctx));
791 
792 	ring = kvmalloc_objs(ring[0], ring_size);
793 	if (!ring)
794 		goto out;
795 	for (i = 0; i < ring_size; ++i) {
796 		ring[i] = srpt_alloc_ioctx(sdev, ioctx_size, buf_cache, dir);
797 		if (!ring[i])
798 			goto err;
799 		ring[i]->index = i;
800 		ring[i]->offset = alignment_offset;
801 	}
802 	goto out;
803 
804 err:
805 	while (--i >= 0)
806 		srpt_free_ioctx(sdev, ring[i], buf_cache, dir);
807 	kvfree(ring);
808 	ring = NULL;
809 out:
810 	return ring;
811 }
812 
813 /**
814  * srpt_free_ioctx_ring - free the ring of SRPT I/O context structures
815  * @ioctx_ring: I/O context ring to be freed.
816  * @sdev: SRPT HCA pointer.
817  * @ring_size: Number of ring elements.
818  * @buf_cache: I/O buffer cache.
819  * @dir: DMA data direction.
820  */
821 static void srpt_free_ioctx_ring(struct srpt_ioctx **ioctx_ring,
822 				 struct srpt_device *sdev, int ring_size,
823 				 struct kmem_cache *buf_cache,
824 				 enum dma_data_direction dir)
825 {
826 	int i;
827 
828 	if (!ioctx_ring)
829 		return;
830 
831 	for (i = 0; i < ring_size; ++i)
832 		srpt_free_ioctx(sdev, ioctx_ring[i], buf_cache, dir);
833 	kvfree(ioctx_ring);
834 }
835 
836 /**
837  * srpt_set_cmd_state - set the state of a SCSI command
838  * @ioctx: Send I/O context.
839  * @new: New I/O context state.
840  *
841  * Does not modify the state of aborted commands. Returns the previous command
842  * state.
843  */
844 static enum srpt_command_state srpt_set_cmd_state(struct srpt_send_ioctx *ioctx,
845 						  enum srpt_command_state new)
846 {
847 	enum srpt_command_state previous;
848 
849 	previous = ioctx->state;
850 	if (previous != SRPT_STATE_DONE)
851 		ioctx->state = new;
852 
853 	return previous;
854 }
855 
856 /**
857  * srpt_test_and_set_cmd_state - test and set the state of a command
858  * @ioctx: Send I/O context.
859  * @old: Current I/O context state.
860  * @new: New I/O context state.
861  *
862  * Returns true if and only if the previous command state was equal to 'old'.
863  */
864 static bool srpt_test_and_set_cmd_state(struct srpt_send_ioctx *ioctx,
865 					enum srpt_command_state old,
866 					enum srpt_command_state new)
867 {
868 	enum srpt_command_state previous;
869 
870 	WARN_ON(!ioctx);
871 	WARN_ON(old == SRPT_STATE_DONE);
872 	WARN_ON(new == SRPT_STATE_NEW);
873 
874 	previous = ioctx->state;
875 	if (previous == old)
876 		ioctx->state = new;
877 
878 	return previous == old;
879 }
880 
881 /**
882  * srpt_post_recv - post an IB receive request
883  * @sdev: SRPT HCA pointer.
884  * @ch: SRPT RDMA channel.
885  * @ioctx: Receive I/O context pointer.
886  */
887 static int srpt_post_recv(struct srpt_device *sdev, struct srpt_rdma_ch *ch,
888 			  struct srpt_recv_ioctx *ioctx)
889 {
890 	struct ib_sge list;
891 	struct ib_recv_wr wr;
892 
893 	BUG_ON(!sdev);
894 	list.addr = ioctx->ioctx.dma + ioctx->ioctx.offset;
895 	list.length = srp_max_req_size;
896 	list.lkey = sdev->lkey;
897 
898 	ioctx->ioctx.cqe.done = srpt_recv_done;
899 	wr.wr_cqe = &ioctx->ioctx.cqe;
900 	wr.next = NULL;
901 	wr.sg_list = &list;
902 	wr.num_sge = 1;
903 
904 	if (sdev->use_srq)
905 		return ib_post_srq_recv(sdev->srq, &wr, NULL);
906 	else
907 		return ib_post_recv(ch->qp, &wr, NULL);
908 }
909 
910 /**
911  * srpt_zerolength_write - perform a zero-length RDMA write
912  * @ch: SRPT RDMA channel.
913  *
914  * A quote from the InfiniBand specification: C9-88: For an HCA responder
915  * using Reliable Connection service, for each zero-length RDMA READ or WRITE
916  * request, the R_Key shall not be validated, even if the request includes
917  * Immediate data.
918  */
919 static int srpt_zerolength_write(struct srpt_rdma_ch *ch)
920 {
921 	struct ib_rdma_wr wr = {
922 		.wr = {
923 			.next		= NULL,
924 			{ .wr_cqe	= &ch->zw_cqe, },
925 			.opcode		= IB_WR_RDMA_WRITE,
926 			.send_flags	= IB_SEND_SIGNALED,
927 		}
928 	};
929 
930 	pr_debug("%s-%d: queued zerolength write\n", ch->sess_name,
931 		 ch->qp->qp_num);
932 
933 	return ib_post_send(ch->qp, &wr.wr, NULL);
934 }
935 
936 static void srpt_zerolength_write_done(struct ib_cq *cq, struct ib_wc *wc)
937 {
938 	struct srpt_rdma_ch *ch = wc->qp->qp_context;
939 
940 	pr_debug("%s-%d wc->status %d\n", ch->sess_name, ch->qp->qp_num,
941 		 wc->status);
942 
943 	if (wc->status == IB_WC_SUCCESS) {
944 		srpt_process_wait_list(ch);
945 	} else {
946 		if (srpt_set_ch_state(ch, CH_DISCONNECTED))
947 			schedule_work(&ch->release_work);
948 		else
949 			pr_debug("%s-%d: already disconnected.\n",
950 				 ch->sess_name, ch->qp->qp_num);
951 	}
952 }
953 
954 static int srpt_alloc_rw_ctxs(struct srpt_send_ioctx *ioctx,
955 		struct srp_direct_buf *db, int nbufs, struct scatterlist **sg,
956 		unsigned *sg_cnt)
957 {
958 	enum dma_data_direction dir = target_reverse_dma_direction(&ioctx->cmd);
959 	struct srpt_rdma_ch *ch = ioctx->ch;
960 	struct scatterlist *prev = NULL;
961 	unsigned prev_nents;
962 	u8 n_rdma, n_rw_ctx;
963 	int ret, i;
964 
965 	if (nbufs == 1) {
966 		ioctx->rw_ctxs = &ioctx->s_rw_ctx;
967 	} else {
968 		ioctx->rw_ctxs = kmalloc_objs(*ioctx->rw_ctxs, nbufs);
969 		if (!ioctx->rw_ctxs)
970 			return -ENOMEM;
971 	}
972 
973 	n_rw_ctx = ioctx->n_rw_ctx;
974 	n_rdma = ioctx->n_rdma;
975 
976 	for (i = ioctx->n_rw_ctx; i < nbufs; i++, db++) {
977 		struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
978 		u64 remote_addr = be64_to_cpu(db->va);
979 		u32 size = be32_to_cpu(db->len);
980 		u32 rkey = be32_to_cpu(db->key);
981 
982 		ret = target_alloc_sgl(&ctx->sg, &ctx->nents, size, false,
983 				i < nbufs - 1);
984 		if (ret)
985 			goto unwind;
986 
987 		ret = rdma_rw_ctx_init(&ctx->rw, ch->qp, ch->sport->port,
988 				ctx->sg, ctx->nents, 0, remote_addr, rkey, dir);
989 		if (ret < 0) {
990 			target_free_sgl(ctx->sg, ctx->nents);
991 			goto unwind;
992 		}
993 
994 		ioctx->n_rdma += ret;
995 		ioctx->n_rw_ctx++;
996 
997 		if (prev) {
998 			sg_unmark_end(&prev[prev_nents - 1]);
999 			sg_chain(prev, prev_nents + 1, ctx->sg);
1000 		} else {
1001 			*sg = ctx->sg;
1002 		}
1003 
1004 		prev = ctx->sg;
1005 		prev_nents = ctx->nents;
1006 
1007 		*sg_cnt += ctx->nents;
1008 	}
1009 
1010 	return 0;
1011 
1012 unwind:
1013 	while (--i >= 0) {
1014 		struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
1015 
1016 		rdma_rw_ctx_destroy(&ctx->rw, ch->qp, ch->sport->port,
1017 				ctx->sg, ctx->nents, dir);
1018 		target_free_sgl(ctx->sg, ctx->nents);
1019 	}
1020 	if (ioctx->rw_ctxs != &ioctx->s_rw_ctx)
1021 		kfree(ioctx->rw_ctxs);
1022 	ioctx->rw_ctxs = NULL;
1023 	ioctx->n_rw_ctx = n_rw_ctx;
1024 	ioctx->n_rdma = n_rdma;
1025 	return ret;
1026 }
1027 
1028 static void srpt_free_rw_ctxs(struct srpt_rdma_ch *ch,
1029 				    struct srpt_send_ioctx *ioctx)
1030 {
1031 	enum dma_data_direction dir = target_reverse_dma_direction(&ioctx->cmd);
1032 	int i;
1033 
1034 	for (i = 0; i < ioctx->n_rw_ctx; i++) {
1035 		struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
1036 
1037 		rdma_rw_ctx_destroy(&ctx->rw, ch->qp, ch->sport->port,
1038 				ctx->sg, ctx->nents, dir);
1039 		target_free_sgl(ctx->sg, ctx->nents);
1040 	}
1041 
1042 	if (ioctx->rw_ctxs != &ioctx->s_rw_ctx)
1043 		kfree(ioctx->rw_ctxs);
1044 }
1045 
1046 static inline void *srpt_get_desc_buf(struct srp_cmd *srp_cmd)
1047 {
1048 	/*
1049 	 * The pointer computations below will only be compiled correctly
1050 	 * if srp_cmd::add_data is declared as s8*, u8*, s8[] or u8[], so check
1051 	 * whether srp_cmd::add_data has been declared as a byte pointer.
1052 	 */
1053 	BUILD_BUG_ON(!__same_type(srp_cmd->add_data[0], (s8)0) &&
1054 		     !__same_type(srp_cmd->add_data[0], (u8)0));
1055 
1056 	/*
1057 	 * According to the SRP spec, the lower two bits of the 'ADDITIONAL
1058 	 * CDB LENGTH' field are reserved and the size in bytes of this field
1059 	 * is four times the value specified in bits 3..7. Hence the "& ~3".
1060 	 */
1061 	return srp_cmd->add_data + (srp_cmd->add_cdb_len & ~3);
1062 }
1063 
1064 /**
1065  * srpt_get_desc_tbl - parse the data descriptors of a SRP_CMD request
1066  * @recv_ioctx: I/O context associated with the received command @srp_cmd.
1067  * @ioctx: I/O context that will be used for responding to the initiator.
1068  * @srp_cmd: Pointer to the SRP_CMD request data.
1069  * @dir: Pointer to the variable to which the transfer direction will be
1070  *   written.
1071  * @sg: [out] scatterlist for the parsed SRP_CMD.
1072  * @sg_cnt: [out] length of @sg.
1073  * @data_len: Pointer to the variable to which the total data length of all
1074  *   descriptors in the SRP_CMD request will be written.
1075  * @imm_data_offset: [in] Offset in SRP_CMD requests at which immediate data
1076  *   starts.
1077  *
1078  * This function initializes ioctx->nrbuf and ioctx->r_bufs.
1079  *
1080  * Returns -EINVAL when the SRP_CMD request contains inconsistent descriptors;
1081  * -ENOMEM when memory allocation fails and zero upon success.
1082  */
1083 static int srpt_get_desc_tbl(struct srpt_recv_ioctx *recv_ioctx,
1084 		struct srpt_send_ioctx *ioctx,
1085 		struct srp_cmd *srp_cmd, enum dma_data_direction *dir,
1086 		struct scatterlist **sg, unsigned int *sg_cnt, u64 *data_len,
1087 		u16 imm_data_offset)
1088 {
1089 	BUG_ON(!dir);
1090 	BUG_ON(!data_len);
1091 
1092 	/*
1093 	 * The lower four bits of the buffer format field contain the DATA-IN
1094 	 * buffer descriptor format, and the highest four bits contain the
1095 	 * DATA-OUT buffer descriptor format.
1096 	 */
1097 	if (srp_cmd->buf_fmt & 0xf)
1098 		/* DATA-IN: transfer data from target to initiator (read). */
1099 		*dir = DMA_FROM_DEVICE;
1100 	else if (srp_cmd->buf_fmt >> 4)
1101 		/* DATA-OUT: transfer data from initiator to target (write). */
1102 		*dir = DMA_TO_DEVICE;
1103 	else
1104 		*dir = DMA_NONE;
1105 
1106 	/* initialize data_direction early as srpt_alloc_rw_ctxs needs it */
1107 	ioctx->cmd.data_direction = *dir;
1108 
1109 	if (((srp_cmd->buf_fmt & 0xf) == SRP_DATA_DESC_DIRECT) ||
1110 	    ((srp_cmd->buf_fmt >> 4) == SRP_DATA_DESC_DIRECT)) {
1111 		struct srp_direct_buf *db = srpt_get_desc_buf(srp_cmd);
1112 
1113 		*data_len = be32_to_cpu(db->len);
1114 		return srpt_alloc_rw_ctxs(ioctx, db, 1, sg, sg_cnt);
1115 	} else if (((srp_cmd->buf_fmt & 0xf) == SRP_DATA_DESC_INDIRECT) ||
1116 		   ((srp_cmd->buf_fmt >> 4) == SRP_DATA_DESC_INDIRECT)) {
1117 		struct srp_indirect_buf *idb = srpt_get_desc_buf(srp_cmd);
1118 		int nbufs = be32_to_cpu(idb->table_desc.len) /
1119 				sizeof(struct srp_direct_buf);
1120 
1121 		if (nbufs >
1122 		    (srp_cmd->data_out_desc_cnt + srp_cmd->data_in_desc_cnt)) {
1123 			pr_err("received unsupported SRP_CMD request type (%u out + %u in != %u / %zu)\n",
1124 			       srp_cmd->data_out_desc_cnt,
1125 			       srp_cmd->data_in_desc_cnt,
1126 			       be32_to_cpu(idb->table_desc.len),
1127 			       sizeof(struct srp_direct_buf));
1128 			return -EINVAL;
1129 		}
1130 
1131 		*data_len = be32_to_cpu(idb->len);
1132 		return srpt_alloc_rw_ctxs(ioctx, idb->desc_list, nbufs,
1133 				sg, sg_cnt);
1134 	} else if ((srp_cmd->buf_fmt >> 4) == SRP_DATA_DESC_IMM) {
1135 		struct srp_imm_buf *imm_buf = srpt_get_desc_buf(srp_cmd);
1136 		void *data = (void *)srp_cmd + imm_data_offset;
1137 		uint32_t len = be32_to_cpu(imm_buf->len);
1138 		uint32_t req_size;
1139 
1140 		if (check_add_overflow((uint32_t)imm_data_offset, len, &req_size) ||
1141 		    req_size > srp_max_req_size) {
1142 			pr_err("Immediate data (length %d + %d) exceeds request size %d\n",
1143 			       imm_data_offset, len, srp_max_req_size);
1144 			return -EINVAL;
1145 		}
1146 		if (recv_ioctx->byte_len < req_size) {
1147 			pr_err("Received too few data - %d < %d\n",
1148 			       recv_ioctx->byte_len, req_size);
1149 			return -EIO;
1150 		}
1151 		/*
1152 		 * The immediate data buffer descriptor must occur before the
1153 		 * immediate data itself.
1154 		 */
1155 		if ((void *)(imm_buf + 1) > (void *)data) {
1156 			pr_err("Received invalid write request\n");
1157 			return -EINVAL;
1158 		}
1159 		*data_len = len;
1160 		ioctx->recv_ioctx = recv_ioctx;
1161 		if ((uintptr_t)data & 511) {
1162 			pr_warn_once("Internal error - the receive buffers are not aligned properly.\n");
1163 			return -EINVAL;
1164 		}
1165 		sg_init_one(&ioctx->imm_sg, data, len);
1166 		*sg = &ioctx->imm_sg;
1167 		*sg_cnt = 1;
1168 		return 0;
1169 	} else {
1170 		*data_len = 0;
1171 		return 0;
1172 	}
1173 }
1174 
1175 /**
1176  * srpt_init_ch_qp - initialize queue pair attributes
1177  * @ch: SRPT RDMA channel.
1178  * @qp: Queue pair pointer.
1179  *
1180  * Initialized the attributes of queue pair 'qp' by allowing local write,
1181  * remote read and remote write. Also transitions 'qp' to state IB_QPS_INIT.
1182  */
1183 static int srpt_init_ch_qp(struct srpt_rdma_ch *ch, struct ib_qp *qp)
1184 {
1185 	struct ib_qp_attr *attr;
1186 	int ret;
1187 
1188 	WARN_ON_ONCE(ch->using_rdma_cm);
1189 
1190 	attr = kzalloc_obj(*attr);
1191 	if (!attr)
1192 		return -ENOMEM;
1193 
1194 	attr->qp_state = IB_QPS_INIT;
1195 	attr->qp_access_flags = IB_ACCESS_LOCAL_WRITE;
1196 	attr->port_num = ch->sport->port;
1197 
1198 	ret = ib_find_cached_pkey(ch->sport->sdev->device, ch->sport->port,
1199 				  ch->pkey, &attr->pkey_index);
1200 	if (ret < 0)
1201 		pr_err("Translating pkey %#x failed (%d) - using index 0\n",
1202 		       ch->pkey, ret);
1203 
1204 	ret = ib_modify_qp(qp, attr,
1205 			   IB_QP_STATE | IB_QP_ACCESS_FLAGS | IB_QP_PORT |
1206 			   IB_QP_PKEY_INDEX);
1207 
1208 	kfree(attr);
1209 	return ret;
1210 }
1211 
1212 /**
1213  * srpt_ch_qp_rtr - change the state of a channel to 'ready to receive' (RTR)
1214  * @ch: channel of the queue pair.
1215  * @qp: queue pair to change the state of.
1216  *
1217  * Returns zero upon success and a negative value upon failure.
1218  *
1219  * Note: currently a struct ib_qp_attr takes 136 bytes on a 64-bit system.
1220  * If this structure ever becomes larger, it might be necessary to allocate
1221  * it dynamically instead of on the stack.
1222  */
1223 static int srpt_ch_qp_rtr(struct srpt_rdma_ch *ch, struct ib_qp *qp)
1224 {
1225 	struct ib_qp_attr qp_attr;
1226 	int attr_mask;
1227 	int ret;
1228 
1229 	WARN_ON_ONCE(ch->using_rdma_cm);
1230 
1231 	qp_attr.qp_state = IB_QPS_RTR;
1232 	ret = ib_cm_init_qp_attr(ch->ib_cm.cm_id, &qp_attr, &attr_mask);
1233 	if (ret)
1234 		goto out;
1235 
1236 	qp_attr.max_dest_rd_atomic = 4;
1237 
1238 	ret = ib_modify_qp(qp, &qp_attr, attr_mask);
1239 
1240 out:
1241 	return ret;
1242 }
1243 
1244 /**
1245  * srpt_ch_qp_rts - change the state of a channel to 'ready to send' (RTS)
1246  * @ch: channel of the queue pair.
1247  * @qp: queue pair to change the state of.
1248  *
1249  * Returns zero upon success and a negative value upon failure.
1250  *
1251  * Note: currently a struct ib_qp_attr takes 136 bytes on a 64-bit system.
1252  * If this structure ever becomes larger, it might be necessary to allocate
1253  * it dynamically instead of on the stack.
1254  */
1255 static int srpt_ch_qp_rts(struct srpt_rdma_ch *ch, struct ib_qp *qp)
1256 {
1257 	struct ib_qp_attr qp_attr;
1258 	int attr_mask;
1259 	int ret;
1260 
1261 	qp_attr.qp_state = IB_QPS_RTS;
1262 	ret = ib_cm_init_qp_attr(ch->ib_cm.cm_id, &qp_attr, &attr_mask);
1263 	if (ret)
1264 		goto out;
1265 
1266 	qp_attr.max_rd_atomic = 4;
1267 
1268 	ret = ib_modify_qp(qp, &qp_attr, attr_mask);
1269 
1270 out:
1271 	return ret;
1272 }
1273 
1274 /**
1275  * srpt_ch_qp_err - set the channel queue pair state to 'error'
1276  * @ch: SRPT RDMA channel.
1277  */
1278 static int srpt_ch_qp_err(struct srpt_rdma_ch *ch)
1279 {
1280 	struct ib_qp_attr qp_attr;
1281 
1282 	qp_attr.qp_state = IB_QPS_ERR;
1283 	return ib_modify_qp(ch->qp, &qp_attr, IB_QP_STATE);
1284 }
1285 
1286 /**
1287  * srpt_get_send_ioctx - obtain an I/O context for sending to the initiator
1288  * @ch: SRPT RDMA channel.
1289  */
1290 static struct srpt_send_ioctx *srpt_get_send_ioctx(struct srpt_rdma_ch *ch)
1291 {
1292 	struct srpt_send_ioctx *ioctx;
1293 	int tag, cpu;
1294 
1295 	BUG_ON(!ch);
1296 
1297 	tag = sbitmap_queue_get(&ch->sess->sess_tag_pool, &cpu);
1298 	if (tag < 0)
1299 		return NULL;
1300 
1301 	ioctx = ch->ioctx_ring[tag];
1302 	BUG_ON(ioctx->ch != ch);
1303 	ioctx->state = SRPT_STATE_NEW;
1304 	WARN_ON_ONCE(ioctx->recv_ioctx);
1305 	ioctx->n_rdma = 0;
1306 	ioctx->n_rw_ctx = 0;
1307 	ioctx->queue_status_only = false;
1308 	/*
1309 	 * transport_init_se_cmd() does not initialize all fields, so do it
1310 	 * here.
1311 	 */
1312 	memset(&ioctx->cmd, 0, sizeof(ioctx->cmd));
1313 	memset(&ioctx->sense_data, 0, sizeof(ioctx->sense_data));
1314 	ioctx->cmd.map_tag = tag;
1315 	ioctx->cmd.map_cpu = cpu;
1316 
1317 	return ioctx;
1318 }
1319 
1320 /**
1321  * srpt_abort_cmd - abort a SCSI command
1322  * @ioctx:   I/O context associated with the SCSI command.
1323  */
1324 static int srpt_abort_cmd(struct srpt_send_ioctx *ioctx)
1325 {
1326 	enum srpt_command_state state;
1327 
1328 	BUG_ON(!ioctx);
1329 
1330 	/*
1331 	 * If the command is in a state where the target core is waiting for
1332 	 * the ib_srpt driver, change the state to the next state.
1333 	 */
1334 
1335 	state = ioctx->state;
1336 	switch (state) {
1337 	case SRPT_STATE_NEED_DATA:
1338 		ioctx->state = SRPT_STATE_DATA_IN;
1339 		break;
1340 	case SRPT_STATE_CMD_RSP_SENT:
1341 	case SRPT_STATE_MGMT_RSP_SENT:
1342 		ioctx->state = SRPT_STATE_DONE;
1343 		break;
1344 	default:
1345 		WARN_ONCE(true, "%s: unexpected I/O context state %d\n",
1346 			  __func__, state);
1347 		break;
1348 	}
1349 
1350 	pr_debug("Aborting cmd with state %d -> %d and tag %lld\n", state,
1351 		 ioctx->state, ioctx->cmd.tag);
1352 
1353 	switch (state) {
1354 	case SRPT_STATE_NEW:
1355 	case SRPT_STATE_DATA_IN:
1356 	case SRPT_STATE_MGMT:
1357 	case SRPT_STATE_DONE:
1358 		/*
1359 		 * Do nothing - defer abort processing until
1360 		 * srpt_queue_response() is invoked.
1361 		 */
1362 		break;
1363 	case SRPT_STATE_NEED_DATA:
1364 		pr_debug("tag %#llx: RDMA read error\n", ioctx->cmd.tag);
1365 		transport_generic_request_failure(&ioctx->cmd,
1366 					TCM_CHECK_CONDITION_ABORT_CMD);
1367 		break;
1368 	case SRPT_STATE_CMD_RSP_SENT:
1369 		/*
1370 		 * SRP_RSP sending failed or the SRP_RSP send completion has
1371 		 * not been received in time.
1372 		 */
1373 		transport_generic_free_cmd(&ioctx->cmd, 0);
1374 		break;
1375 	case SRPT_STATE_MGMT_RSP_SENT:
1376 		transport_generic_free_cmd(&ioctx->cmd, 0);
1377 		break;
1378 	default:
1379 		WARN(1, "Unexpected command state (%d)", state);
1380 		break;
1381 	}
1382 
1383 	return state;
1384 }
1385 
1386 /**
1387  * srpt_rdma_read_done - RDMA read completion callback
1388  * @cq: Completion queue.
1389  * @wc: Work completion.
1390  *
1391  * XXX: what is now target_execute_cmd used to be asynchronous, and unmapping
1392  * the data that has been transferred via IB RDMA had to be postponed until the
1393  * check_stop_free() callback.  None of this is necessary anymore and needs to
1394  * be cleaned up.
1395  */
1396 static void srpt_rdma_read_done(struct ib_cq *cq, struct ib_wc *wc)
1397 {
1398 	struct srpt_rdma_ch *ch = wc->qp->qp_context;
1399 	struct srpt_send_ioctx *ioctx =
1400 		container_of(wc->wr_cqe, struct srpt_send_ioctx, rdma_cqe);
1401 
1402 	WARN_ON(ioctx->n_rdma <= 0);
1403 	atomic_add(ioctx->n_rdma, &ch->sq_wr_avail);
1404 	ioctx->n_rdma = 0;
1405 
1406 	if (unlikely(wc->status != IB_WC_SUCCESS)) {
1407 		pr_info("RDMA_READ for ioctx 0x%p failed with status %d\n",
1408 			ioctx, wc->status);
1409 		srpt_abort_cmd(ioctx);
1410 		return;
1411 	}
1412 
1413 	if (srpt_test_and_set_cmd_state(ioctx, SRPT_STATE_NEED_DATA,
1414 					SRPT_STATE_DATA_IN))
1415 		target_execute_cmd(&ioctx->cmd);
1416 	else
1417 		pr_err("%s[%d]: wrong state = %d\n", __func__,
1418 		       __LINE__, ioctx->state);
1419 }
1420 
1421 /**
1422  * srpt_build_cmd_rsp - build a SRP_RSP response
1423  * @ch: RDMA channel through which the request has been received.
1424  * @ioctx: I/O context associated with the SRP_CMD request. The response will
1425  *   be built in the buffer ioctx->buf points at and hence this function will
1426  *   overwrite the request data.
1427  * @tag: tag of the request for which this response is being generated.
1428  * @status: value for the STATUS field of the SRP_RSP information unit.
1429  *
1430  * Returns the size in bytes of the SRP_RSP response.
1431  *
1432  * An SRP_RSP response contains a SCSI status or service response. See also
1433  * section 6.9 in the SRP r16a document for the format of an SRP_RSP
1434  * response. See also SPC-2 for more information about sense data.
1435  */
1436 static int srpt_build_cmd_rsp(struct srpt_rdma_ch *ch,
1437 			      struct srpt_send_ioctx *ioctx, u64 tag,
1438 			      int status)
1439 {
1440 	struct se_cmd *cmd = &ioctx->cmd;
1441 	struct srp_rsp *srp_rsp;
1442 	const u8 *sense_data;
1443 	int sense_data_len, max_sense_len;
1444 	u32 resid = cmd->residual_count;
1445 
1446 	/*
1447 	 * The lowest bit of all SAM-3 status codes is zero (see also
1448 	 * paragraph 5.3 in SAM-3).
1449 	 */
1450 	WARN_ON(status & 1);
1451 
1452 	srp_rsp = ioctx->ioctx.buf;
1453 	BUG_ON(!srp_rsp);
1454 
1455 	sense_data = ioctx->sense_data;
1456 	sense_data_len = ioctx->cmd.scsi_sense_length;
1457 	WARN_ON(sense_data_len > sizeof(ioctx->sense_data));
1458 
1459 	memset(srp_rsp, 0, sizeof(*srp_rsp));
1460 	srp_rsp->opcode = SRP_RSP;
1461 	srp_rsp->req_lim_delta =
1462 		cpu_to_be32(1 + atomic_xchg(&ch->req_lim_delta, 0));
1463 	srp_rsp->tag = tag;
1464 	srp_rsp->status = status;
1465 
1466 	if (cmd->se_cmd_flags & SCF_UNDERFLOW_BIT) {
1467 		if (cmd->data_direction == DMA_TO_DEVICE) {
1468 			/* residual data from an underflow write */
1469 			srp_rsp->flags = SRP_RSP_FLAG_DOUNDER;
1470 			srp_rsp->data_out_res_cnt = cpu_to_be32(resid);
1471 		} else if (cmd->data_direction == DMA_FROM_DEVICE) {
1472 			/* residual data from an underflow read */
1473 			srp_rsp->flags = SRP_RSP_FLAG_DIUNDER;
1474 			srp_rsp->data_in_res_cnt = cpu_to_be32(resid);
1475 		}
1476 	} else if (cmd->se_cmd_flags & SCF_OVERFLOW_BIT) {
1477 		if (cmd->data_direction == DMA_TO_DEVICE) {
1478 			/* residual data from an overflow write */
1479 			srp_rsp->flags = SRP_RSP_FLAG_DOOVER;
1480 			srp_rsp->data_out_res_cnt = cpu_to_be32(resid);
1481 		} else if (cmd->data_direction == DMA_FROM_DEVICE) {
1482 			/* residual data from an overflow read */
1483 			srp_rsp->flags = SRP_RSP_FLAG_DIOVER;
1484 			srp_rsp->data_in_res_cnt = cpu_to_be32(resid);
1485 		}
1486 	}
1487 
1488 	if (sense_data_len) {
1489 		BUILD_BUG_ON(MIN_MAX_RSP_SIZE <= sizeof(*srp_rsp));
1490 		max_sense_len = ch->max_ti_iu_len - sizeof(*srp_rsp);
1491 		if (sense_data_len > max_sense_len) {
1492 			pr_warn("truncated sense data from %d to %d bytes\n",
1493 				sense_data_len, max_sense_len);
1494 			sense_data_len = max_sense_len;
1495 		}
1496 
1497 		srp_rsp->flags |= SRP_RSP_FLAG_SNSVALID;
1498 		srp_rsp->sense_data_len = cpu_to_be32(sense_data_len);
1499 		memcpy(srp_rsp->data, sense_data, sense_data_len);
1500 	}
1501 
1502 	return sizeof(*srp_rsp) + sense_data_len;
1503 }
1504 
1505 /**
1506  * srpt_build_tskmgmt_rsp - build a task management response
1507  * @ch:       RDMA channel through which the request has been received.
1508  * @ioctx:    I/O context in which the SRP_RSP response will be built.
1509  * @rsp_code: RSP_CODE that will be stored in the response.
1510  * @tag:      Tag of the request for which this response is being generated.
1511  *
1512  * Returns the size in bytes of the SRP_RSP response.
1513  *
1514  * An SRP_RSP response contains a SCSI status or service response. See also
1515  * section 6.9 in the SRP r16a document for the format of an SRP_RSP
1516  * response.
1517  */
1518 static int srpt_build_tskmgmt_rsp(struct srpt_rdma_ch *ch,
1519 				  struct srpt_send_ioctx *ioctx,
1520 				  u8 rsp_code, u64 tag)
1521 {
1522 	struct srp_rsp *srp_rsp;
1523 	int resp_data_len;
1524 	int resp_len;
1525 
1526 	resp_data_len = 4;
1527 	resp_len = sizeof(*srp_rsp) + resp_data_len;
1528 
1529 	srp_rsp = ioctx->ioctx.buf;
1530 	BUG_ON(!srp_rsp);
1531 	memset(srp_rsp, 0, sizeof(*srp_rsp));
1532 
1533 	srp_rsp->opcode = SRP_RSP;
1534 	srp_rsp->req_lim_delta =
1535 		cpu_to_be32(1 + atomic_xchg(&ch->req_lim_delta, 0));
1536 	srp_rsp->tag = tag;
1537 
1538 	srp_rsp->flags |= SRP_RSP_FLAG_RSPVALID;
1539 	srp_rsp->resp_data_len = cpu_to_be32(resp_data_len);
1540 	srp_rsp->data[3] = rsp_code;
1541 
1542 	return resp_len;
1543 }
1544 
1545 static int srpt_check_stop_free(struct se_cmd *cmd)
1546 {
1547 	struct srpt_send_ioctx *ioctx = container_of(cmd,
1548 				struct srpt_send_ioctx, cmd);
1549 
1550 	return target_put_sess_cmd(&ioctx->cmd);
1551 }
1552 
1553 /**
1554  * srpt_handle_cmd - process a SRP_CMD information unit
1555  * @ch: SRPT RDMA channel.
1556  * @recv_ioctx: Receive I/O context.
1557  * @send_ioctx: Send I/O context.
1558  */
1559 static void srpt_handle_cmd(struct srpt_rdma_ch *ch,
1560 			    struct srpt_recv_ioctx *recv_ioctx,
1561 			    struct srpt_send_ioctx *send_ioctx)
1562 {
1563 	struct se_cmd *cmd;
1564 	struct srp_cmd *srp_cmd;
1565 	struct scatterlist *sg = NULL;
1566 	unsigned sg_cnt = 0;
1567 	u64 data_len;
1568 	enum dma_data_direction dir;
1569 	int rc;
1570 
1571 	BUG_ON(!send_ioctx);
1572 
1573 	srp_cmd = recv_ioctx->ioctx.buf + recv_ioctx->ioctx.offset;
1574 	cmd = &send_ioctx->cmd;
1575 	cmd->tag = srp_cmd->tag;
1576 
1577 	switch (srp_cmd->task_attr) {
1578 	case SRP_CMD_SIMPLE_Q:
1579 		cmd->sam_task_attr = TCM_SIMPLE_TAG;
1580 		break;
1581 	case SRP_CMD_ORDERED_Q:
1582 	default:
1583 		cmd->sam_task_attr = TCM_ORDERED_TAG;
1584 		break;
1585 	case SRP_CMD_HEAD_OF_Q:
1586 		cmd->sam_task_attr = TCM_HEAD_TAG;
1587 		break;
1588 	case SRP_CMD_ACA:
1589 		cmd->sam_task_attr = TCM_ACA_TAG;
1590 		break;
1591 	}
1592 
1593 	rc = srpt_get_desc_tbl(recv_ioctx, send_ioctx, srp_cmd, &dir,
1594 			       &sg, &sg_cnt, &data_len, ch->imm_data_offset);
1595 	if (rc) {
1596 		if (rc != -EAGAIN) {
1597 			pr_err("0x%llx: parsing SRP descriptor table failed.\n",
1598 			       srp_cmd->tag);
1599 		}
1600 		goto busy;
1601 	}
1602 
1603 	rc = target_init_cmd(cmd, ch->sess, &send_ioctx->sense_data[0],
1604 			     scsilun_to_int(&srp_cmd->lun), data_len,
1605 			     cmd->sam_task_attr, dir, TARGET_SCF_ACK_KREF);
1606 	if (rc != 0) {
1607 		pr_debug("target_submit_cmd() returned %d for tag %#llx\n", rc,
1608 			 srp_cmd->tag);
1609 		goto busy;
1610 	}
1611 
1612 	if (target_submit_prep(cmd, srp_cmd->cdb, sg, sg_cnt, NULL, 0, NULL, 0,
1613 			       GFP_KERNEL))
1614 		return;
1615 
1616 	target_submit(cmd);
1617 	return;
1618 
1619 busy:
1620 	target_send_busy(cmd);
1621 }
1622 
1623 static int srp_tmr_to_tcm(int fn)
1624 {
1625 	switch (fn) {
1626 	case SRP_TSK_ABORT_TASK:
1627 		return TMR_ABORT_TASK;
1628 	case SRP_TSK_ABORT_TASK_SET:
1629 		return TMR_ABORT_TASK_SET;
1630 	case SRP_TSK_CLEAR_TASK_SET:
1631 		return TMR_CLEAR_TASK_SET;
1632 	case SRP_TSK_LUN_RESET:
1633 		return TMR_LUN_RESET;
1634 	case SRP_TSK_CLEAR_ACA:
1635 		return TMR_CLEAR_ACA;
1636 	default:
1637 		return -1;
1638 	}
1639 }
1640 
1641 /**
1642  * srpt_handle_tsk_mgmt - process a SRP_TSK_MGMT information unit
1643  * @ch: SRPT RDMA channel.
1644  * @recv_ioctx: Receive I/O context.
1645  * @send_ioctx: Send I/O context.
1646  *
1647  * Returns 0 if and only if the request will be processed by the target core.
1648  *
1649  * For more information about SRP_TSK_MGMT information units, see also section
1650  * 6.7 in the SRP r16a document.
1651  */
1652 static void srpt_handle_tsk_mgmt(struct srpt_rdma_ch *ch,
1653 				 struct srpt_recv_ioctx *recv_ioctx,
1654 				 struct srpt_send_ioctx *send_ioctx)
1655 {
1656 	struct srp_tsk_mgmt *srp_tsk;
1657 	struct se_cmd *cmd;
1658 	struct se_session *sess = ch->sess;
1659 	int tcm_tmr;
1660 	int rc;
1661 
1662 	BUG_ON(!send_ioctx);
1663 
1664 	srp_tsk = recv_ioctx->ioctx.buf + recv_ioctx->ioctx.offset;
1665 	cmd = &send_ioctx->cmd;
1666 
1667 	pr_debug("recv tsk_mgmt fn %d for task_tag %lld and cmd tag %lld ch %p sess %p\n",
1668 		 srp_tsk->tsk_mgmt_func, srp_tsk->task_tag, srp_tsk->tag, ch,
1669 		 ch->sess);
1670 
1671 	srpt_set_cmd_state(send_ioctx, SRPT_STATE_MGMT);
1672 	send_ioctx->cmd.tag = srp_tsk->tag;
1673 	tcm_tmr = srp_tmr_to_tcm(srp_tsk->tsk_mgmt_func);
1674 	rc = target_submit_tmr(&send_ioctx->cmd, sess, NULL,
1675 			       scsilun_to_int(&srp_tsk->lun), srp_tsk, tcm_tmr,
1676 			       GFP_KERNEL, srp_tsk->task_tag,
1677 			       TARGET_SCF_ACK_KREF);
1678 	if (rc != 0) {
1679 		send_ioctx->cmd.se_tmr_req->response = TMR_FUNCTION_REJECTED;
1680 		cmd->se_tfo->queue_tm_rsp(cmd);
1681 	}
1682 	return;
1683 }
1684 
1685 /**
1686  * srpt_handle_new_iu - process a newly received information unit
1687  * @ch:    RDMA channel through which the information unit has been received.
1688  * @recv_ioctx: Receive I/O context associated with the information unit.
1689  */
1690 static bool
1691 srpt_handle_new_iu(struct srpt_rdma_ch *ch, struct srpt_recv_ioctx *recv_ioctx)
1692 {
1693 	struct srpt_send_ioctx *send_ioctx = NULL;
1694 	struct srp_cmd *srp_cmd;
1695 	bool res = false;
1696 	u8 opcode;
1697 
1698 	BUG_ON(!ch);
1699 	BUG_ON(!recv_ioctx);
1700 
1701 	if (unlikely(ch->state == CH_CONNECTING))
1702 		goto push;
1703 
1704 	ib_dma_sync_single_for_cpu(ch->sport->sdev->device,
1705 				   recv_ioctx->ioctx.dma,
1706 				   recv_ioctx->ioctx.offset + srp_max_req_size,
1707 				   DMA_FROM_DEVICE);
1708 
1709 	srp_cmd = recv_ioctx->ioctx.buf + recv_ioctx->ioctx.offset;
1710 	opcode = srp_cmd->opcode;
1711 	if (opcode == SRP_CMD || opcode == SRP_TSK_MGMT) {
1712 		send_ioctx = srpt_get_send_ioctx(ch);
1713 		if (unlikely(!send_ioctx))
1714 			goto push;
1715 	}
1716 
1717 	if (!list_empty(&recv_ioctx->wait_list)) {
1718 		WARN_ON_ONCE(!ch->processing_wait_list);
1719 		list_del_init(&recv_ioctx->wait_list);
1720 	}
1721 
1722 	switch (opcode) {
1723 	case SRP_CMD:
1724 		srpt_handle_cmd(ch, recv_ioctx, send_ioctx);
1725 		break;
1726 	case SRP_TSK_MGMT:
1727 		srpt_handle_tsk_mgmt(ch, recv_ioctx, send_ioctx);
1728 		break;
1729 	case SRP_I_LOGOUT:
1730 		pr_err("Not yet implemented: SRP_I_LOGOUT\n");
1731 		break;
1732 	case SRP_CRED_RSP:
1733 		pr_debug("received SRP_CRED_RSP\n");
1734 		break;
1735 	case SRP_AER_RSP:
1736 		pr_debug("received SRP_AER_RSP\n");
1737 		break;
1738 	case SRP_RSP:
1739 		pr_err("Received SRP_RSP\n");
1740 		break;
1741 	default:
1742 		pr_err("received IU with unknown opcode 0x%x\n", opcode);
1743 		break;
1744 	}
1745 
1746 	if (!send_ioctx || !send_ioctx->recv_ioctx)
1747 		srpt_post_recv(ch->sport->sdev, ch, recv_ioctx);
1748 	res = true;
1749 
1750 out:
1751 	return res;
1752 
1753 push:
1754 	if (list_empty(&recv_ioctx->wait_list)) {
1755 		WARN_ON_ONCE(ch->processing_wait_list);
1756 		list_add_tail(&recv_ioctx->wait_list, &ch->cmd_wait_list);
1757 	}
1758 	goto out;
1759 }
1760 
1761 static void srpt_recv_done(struct ib_cq *cq, struct ib_wc *wc)
1762 {
1763 	struct srpt_rdma_ch *ch = wc->qp->qp_context;
1764 	struct srpt_recv_ioctx *ioctx =
1765 		container_of(wc->wr_cqe, struct srpt_recv_ioctx, ioctx.cqe);
1766 
1767 	if (wc->status == IB_WC_SUCCESS) {
1768 		int req_lim;
1769 
1770 		req_lim = atomic_dec_return(&ch->req_lim);
1771 		if (unlikely(req_lim < 0))
1772 			pr_err("req_lim = %d < 0\n", req_lim);
1773 		ioctx->byte_len = wc->byte_len;
1774 		srpt_handle_new_iu(ch, ioctx);
1775 	} else {
1776 		pr_info_ratelimited("receiving failed for ioctx %p with status %d\n",
1777 				    ioctx, wc->status);
1778 	}
1779 }
1780 
1781 /*
1782  * This function must be called from the context in which RDMA completions are
1783  * processed because it accesses the wait list without protection against
1784  * access from other threads.
1785  */
1786 static void srpt_process_wait_list(struct srpt_rdma_ch *ch)
1787 {
1788 	struct srpt_recv_ioctx *recv_ioctx, *tmp;
1789 
1790 	WARN_ON_ONCE(ch->state == CH_CONNECTING);
1791 
1792 	if (list_empty(&ch->cmd_wait_list))
1793 		return;
1794 
1795 	WARN_ON_ONCE(ch->processing_wait_list);
1796 	ch->processing_wait_list = true;
1797 	list_for_each_entry_safe(recv_ioctx, tmp, &ch->cmd_wait_list,
1798 				 wait_list) {
1799 		if (!srpt_handle_new_iu(ch, recv_ioctx))
1800 			break;
1801 	}
1802 	ch->processing_wait_list = false;
1803 }
1804 
1805 /**
1806  * srpt_send_done - send completion callback
1807  * @cq: Completion queue.
1808  * @wc: Work completion.
1809  *
1810  * Note: Although this has not yet been observed during tests, at least in
1811  * theory it is possible that the srpt_get_send_ioctx() call invoked by
1812  * srpt_handle_new_iu() fails. This is possible because the req_lim_delta
1813  * value in each response is set to one, and it is possible that this response
1814  * makes the initiator send a new request before the send completion for that
1815  * response has been processed. This could e.g. happen if the call to
1816  * srpt_put_send_iotcx() is delayed because of a higher priority interrupt or
1817  * if IB retransmission causes generation of the send completion to be
1818  * delayed. Incoming information units for which srpt_get_send_ioctx() fails
1819  * are queued on cmd_wait_list. The code below processes these delayed
1820  * requests one at a time.
1821  */
1822 static void srpt_send_done(struct ib_cq *cq, struct ib_wc *wc)
1823 {
1824 	struct srpt_rdma_ch *ch = wc->qp->qp_context;
1825 	struct srpt_send_ioctx *ioctx =
1826 		container_of(wc->wr_cqe, struct srpt_send_ioctx, ioctx.cqe);
1827 	enum srpt_command_state state;
1828 
1829 	state = srpt_set_cmd_state(ioctx, SRPT_STATE_DONE);
1830 
1831 	WARN_ON(state != SRPT_STATE_CMD_RSP_SENT &&
1832 		state != SRPT_STATE_MGMT_RSP_SENT);
1833 
1834 	atomic_add(1 + ioctx->n_rdma, &ch->sq_wr_avail);
1835 
1836 	if (wc->status != IB_WC_SUCCESS)
1837 		pr_info("sending response for ioctx 0x%p failed with status %d\n",
1838 			ioctx, wc->status);
1839 
1840 	if (state != SRPT_STATE_DONE) {
1841 		transport_generic_free_cmd(&ioctx->cmd, 0);
1842 	} else {
1843 		pr_err("IB completion has been received too late for wr_id = %u.\n",
1844 		       ioctx->ioctx.index);
1845 	}
1846 
1847 	srpt_process_wait_list(ch);
1848 }
1849 
1850 /**
1851  * srpt_create_ch_ib - create receive and send completion queues
1852  * @ch: SRPT RDMA channel.
1853  */
1854 static int srpt_create_ch_ib(struct srpt_rdma_ch *ch)
1855 {
1856 	struct ib_qp_init_attr *qp_init;
1857 	struct srpt_port *sport = ch->sport;
1858 	struct srpt_device *sdev = sport->sdev;
1859 	const struct ib_device_attr *attrs = &sdev->device->attrs;
1860 	u32 sq_size = sport->port_attrib.srp_sq_size;
1861 	int i, ret;
1862 
1863 	WARN_ON(ch->rq_size < 1);
1864 
1865 	ret = -ENOMEM;
1866 	qp_init = kzalloc_obj(*qp_init);
1867 	if (!qp_init)
1868 		goto out;
1869 
1870 retry:
1871 	ch->cq = ib_cq_pool_get(sdev->device, ch->rq_size + sq_size, -1,
1872 				 IB_POLL_WORKQUEUE);
1873 	if (IS_ERR(ch->cq)) {
1874 		ret = PTR_ERR(ch->cq);
1875 		pr_err("failed to create CQ cqe= %d ret= %pe\n",
1876 		       ch->rq_size + sq_size, ch->cq);
1877 		goto out;
1878 	}
1879 	ch->cq_size = ch->rq_size + sq_size;
1880 
1881 	qp_init->qp_context = (void *)ch;
1882 	qp_init->event_handler = srpt_qp_event;
1883 	qp_init->send_cq = ch->cq;
1884 	qp_init->recv_cq = ch->cq;
1885 	qp_init->sq_sig_type = IB_SIGNAL_REQ_WR;
1886 	qp_init->qp_type = IB_QPT_RC;
1887 	/*
1888 	 * We divide up our send queue size into half SEND WRs to send the
1889 	 * completions, and half R/W contexts to actually do the RDMA
1890 	 * READ/WRITE transfers.  Note that we need to allocate CQ slots for
1891 	 * both both, as RDMA contexts will also post completions for the
1892 	 * RDMA READ case.
1893 	 */
1894 	qp_init->cap.max_send_wr = min(sq_size / 2, attrs->max_qp_wr);
1895 	qp_init->cap.max_rdma_ctxs = sq_size / 2;
1896 	qp_init->cap.max_send_sge = attrs->max_send_sge;
1897 	qp_init->cap.max_recv_sge = 1;
1898 	qp_init->port_num = ch->sport->port;
1899 	if (sdev->use_srq)
1900 		qp_init->srq = sdev->srq;
1901 	else
1902 		qp_init->cap.max_recv_wr = ch->rq_size;
1903 
1904 	if (ch->using_rdma_cm) {
1905 		ret = rdma_create_qp(ch->rdma_cm.cm_id, sdev->pd, qp_init);
1906 		ch->qp = ch->rdma_cm.cm_id->qp;
1907 	} else {
1908 		ch->qp = ib_create_qp(sdev->pd, qp_init);
1909 		if (!IS_ERR(ch->qp)) {
1910 			ret = srpt_init_ch_qp(ch, ch->qp);
1911 			if (ret)
1912 				ib_destroy_qp(ch->qp);
1913 		} else {
1914 			ret = PTR_ERR(ch->qp);
1915 		}
1916 	}
1917 	if (ret) {
1918 		bool retry = sq_size > MIN_SRPT_SQ_SIZE;
1919 
1920 		if (retry) {
1921 			pr_debug("failed to create queue pair with sq_size = %u (%d) - retrying\n",
1922 				 sq_size, ret);
1923 			ib_cq_pool_put(ch->cq, ch->cq_size);
1924 			sq_size = max(sq_size / 2, MIN_SRPT_SQ_SIZE);
1925 			goto retry;
1926 		} else {
1927 			pr_err("failed to create queue pair with sq_size = %u (%d)\n",
1928 			       sq_size, ret);
1929 			goto err_destroy_cq;
1930 		}
1931 	}
1932 
1933 	atomic_set(&ch->sq_wr_avail, qp_init->cap.max_send_wr);
1934 
1935 	pr_debug("%s: max_cqe= %d max_sge= %d sq_size = %u ch= %p\n",
1936 		 __func__, ch->cq->cqe, qp_init->cap.max_send_sge,
1937 		 qp_init->cap.max_send_wr, ch);
1938 
1939 	if (!sdev->use_srq)
1940 		for (i = 0; i < ch->rq_size; i++)
1941 			srpt_post_recv(sdev, ch, ch->ioctx_recv_ring[i]);
1942 
1943 out:
1944 	kfree(qp_init);
1945 	return ret;
1946 
1947 err_destroy_cq:
1948 	ch->qp = NULL;
1949 	ib_cq_pool_put(ch->cq, ch->cq_size);
1950 	goto out;
1951 }
1952 
1953 static void srpt_destroy_ch_ib(struct srpt_rdma_ch *ch)
1954 {
1955 	ib_destroy_qp(ch->qp);
1956 	ib_cq_pool_put(ch->cq, ch->cq_size);
1957 }
1958 
1959 /**
1960  * srpt_close_ch - close a RDMA channel
1961  * @ch: SRPT RDMA channel.
1962  *
1963  * Make sure all resources associated with the channel will be deallocated at
1964  * an appropriate time.
1965  *
1966  * Returns true if and only if the channel state has been modified into
1967  * CH_DRAINING.
1968  */
1969 static bool srpt_close_ch(struct srpt_rdma_ch *ch)
1970 {
1971 	int ret;
1972 
1973 	if (!srpt_set_ch_state(ch, CH_DRAINING)) {
1974 		pr_debug("%s: already closed\n", ch->sess_name);
1975 		return false;
1976 	}
1977 
1978 	kref_get(&ch->kref);
1979 
1980 	ret = srpt_ch_qp_err(ch);
1981 	if (ret < 0)
1982 		pr_err("%s-%d: changing queue pair into error state failed: %d\n",
1983 		       ch->sess_name, ch->qp->qp_num, ret);
1984 
1985 	ret = srpt_zerolength_write(ch);
1986 	if (ret < 0) {
1987 		pr_err("%s-%d: queuing zero-length write failed: %d\n",
1988 		       ch->sess_name, ch->qp->qp_num, ret);
1989 		if (srpt_set_ch_state(ch, CH_DISCONNECTED))
1990 			schedule_work(&ch->release_work);
1991 		else
1992 			WARN_ON_ONCE(true);
1993 	}
1994 
1995 	kref_put(&ch->kref, srpt_free_ch);
1996 
1997 	return true;
1998 }
1999 
2000 /*
2001  * Change the channel state into CH_DISCONNECTING. If a channel has not yet
2002  * reached the connected state, close it. If a channel is in the connected
2003  * state, send a DREQ. If a DREQ has been received, send a DREP. Note: it is
2004  * the responsibility of the caller to ensure that this function is not
2005  * invoked concurrently with the code that accepts a connection. This means
2006  * that this function must either be invoked from inside a CM callback
2007  * function or that it must be invoked with the srpt_port.mutex held.
2008  */
2009 static int srpt_disconnect_ch(struct srpt_rdma_ch *ch)
2010 {
2011 	int ret;
2012 
2013 	if (!srpt_set_ch_state(ch, CH_DISCONNECTING))
2014 		return -ENOTCONN;
2015 
2016 	if (ch->using_rdma_cm) {
2017 		ret = rdma_disconnect(ch->rdma_cm.cm_id);
2018 	} else {
2019 		ret = ib_send_cm_dreq(ch->ib_cm.cm_id, NULL, 0);
2020 		if (ret < 0)
2021 			ret = ib_send_cm_drep(ch->ib_cm.cm_id, NULL, 0);
2022 	}
2023 
2024 	if (ret < 0 && srpt_close_ch(ch))
2025 		ret = 0;
2026 
2027 	return ret;
2028 }
2029 
2030 /* Send DREQ and wait for DREP. */
2031 static void srpt_disconnect_ch_sync(struct srpt_rdma_ch *ch)
2032 {
2033 	DECLARE_COMPLETION_ONSTACK(closed);
2034 	struct srpt_port *sport = ch->sport;
2035 
2036 	pr_debug("ch %s-%d state %d\n", ch->sess_name, ch->qp->qp_num,
2037 		 ch->state);
2038 
2039 	ch->closed = &closed;
2040 
2041 	mutex_lock(&sport->mutex);
2042 	srpt_disconnect_ch(ch);
2043 	mutex_unlock(&sport->mutex);
2044 
2045 	while (wait_for_completion_timeout(&closed, 5 * HZ) == 0)
2046 		pr_info("%s(%s-%d state %d): still waiting ...\n", __func__,
2047 			ch->sess_name, ch->qp->qp_num, ch->state);
2048 
2049 }
2050 
2051 static void __srpt_close_all_ch(struct srpt_port *sport)
2052 {
2053 	struct srpt_nexus *nexus;
2054 	struct srpt_rdma_ch *ch;
2055 
2056 	lockdep_assert_held(&sport->mutex);
2057 
2058 	list_for_each_entry(nexus, &sport->nexus_list, entry) {
2059 		list_for_each_entry(ch, &nexus->ch_list, list) {
2060 			if (srpt_disconnect_ch(ch) >= 0)
2061 				pr_info("Closing channel %s-%d because target %s_%d has been disabled\n",
2062 					ch->sess_name, ch->qp->qp_num,
2063 					dev_name(&sport->sdev->device->dev),
2064 					sport->port);
2065 			srpt_close_ch(ch);
2066 		}
2067 	}
2068 }
2069 
2070 /*
2071  * Look up (i_port_id, t_port_id) in sport->nexus_list. Create an entry if
2072  * it does not yet exist.
2073  */
2074 static struct srpt_nexus *srpt_get_nexus(struct srpt_port *sport,
2075 					 const u8 i_port_id[16],
2076 					 const u8 t_port_id[16])
2077 {
2078 	struct srpt_nexus *nexus = NULL, *tmp_nexus = NULL, *n;
2079 
2080 	for (;;) {
2081 		mutex_lock(&sport->mutex);
2082 		list_for_each_entry(n, &sport->nexus_list, entry) {
2083 			if (memcmp(n->i_port_id, i_port_id, 16) == 0 &&
2084 			    memcmp(n->t_port_id, t_port_id, 16) == 0) {
2085 				nexus = n;
2086 				break;
2087 			}
2088 		}
2089 		if (!nexus && tmp_nexus) {
2090 			list_add_tail_rcu(&tmp_nexus->entry,
2091 					  &sport->nexus_list);
2092 			swap(nexus, tmp_nexus);
2093 		}
2094 		mutex_unlock(&sport->mutex);
2095 
2096 		if (nexus)
2097 			break;
2098 		tmp_nexus = kzalloc_obj(*nexus);
2099 		if (!tmp_nexus) {
2100 			nexus = ERR_PTR(-ENOMEM);
2101 			break;
2102 		}
2103 		INIT_LIST_HEAD(&tmp_nexus->ch_list);
2104 		memcpy(tmp_nexus->i_port_id, i_port_id, 16);
2105 		memcpy(tmp_nexus->t_port_id, t_port_id, 16);
2106 	}
2107 
2108 	kfree(tmp_nexus);
2109 
2110 	return nexus;
2111 }
2112 
2113 static void srpt_set_enabled(struct srpt_port *sport, bool enabled)
2114 	__must_hold(&sport->mutex)
2115 {
2116 	lockdep_assert_held(&sport->mutex);
2117 
2118 	if (sport->enabled == enabled)
2119 		return;
2120 	sport->enabled = enabled;
2121 	if (!enabled)
2122 		__srpt_close_all_ch(sport);
2123 }
2124 
2125 static void srpt_drop_sport_ref(struct srpt_port *sport)
2126 {
2127 	if (atomic_dec_return(&sport->refcount) == 0 && sport->freed_channels)
2128 		complete(sport->freed_channels);
2129 }
2130 
2131 static void srpt_free_ch(struct kref *kref)
2132 {
2133 	struct srpt_rdma_ch *ch = container_of(kref, struct srpt_rdma_ch, kref);
2134 
2135 	srpt_drop_sport_ref(ch->sport);
2136 	kfree_rcu(ch, rcu);
2137 }
2138 
2139 /*
2140  * Shut down the SCSI target session, tell the connection manager to
2141  * disconnect the associated RDMA channel, transition the QP to the error
2142  * state and remove the channel from the channel list. This function is
2143  * typically called from inside srpt_zerolength_write_done(). Concurrent
2144  * srpt_zerolength_write() calls from inside srpt_close_ch() are possible
2145  * as long as the channel is on sport->nexus_list.
2146  */
2147 static void srpt_release_channel_work(struct work_struct *w)
2148 {
2149 	struct srpt_rdma_ch *ch;
2150 	struct srpt_device *sdev;
2151 	struct srpt_port *sport;
2152 	struct se_session *se_sess;
2153 
2154 	ch = container_of(w, struct srpt_rdma_ch, release_work);
2155 	pr_debug("%s-%d\n", ch->sess_name, ch->qp->qp_num);
2156 
2157 	sdev = ch->sport->sdev;
2158 	BUG_ON(!sdev);
2159 
2160 	se_sess = ch->sess;
2161 	BUG_ON(!se_sess);
2162 
2163 	target_stop_session(se_sess);
2164 	target_wait_for_sess_cmds(se_sess);
2165 
2166 	target_remove_session(se_sess);
2167 	ch->sess = NULL;
2168 
2169 	if (ch->using_rdma_cm)
2170 		rdma_destroy_id(ch->rdma_cm.cm_id);
2171 	else
2172 		ib_destroy_cm_id(ch->ib_cm.cm_id);
2173 
2174 	sport = ch->sport;
2175 	mutex_lock(&sport->mutex);
2176 	list_del_rcu(&ch->list);
2177 	mutex_unlock(&sport->mutex);
2178 
2179 	if (ch->closed)
2180 		complete(ch->closed);
2181 
2182 	srpt_destroy_ch_ib(ch);
2183 
2184 	srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_ring,
2185 			     ch->sport->sdev, ch->rq_size,
2186 			     ch->rsp_buf_cache, DMA_TO_DEVICE);
2187 
2188 	srpt_cache_put(ch->rsp_buf_cache);
2189 
2190 	srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_recv_ring,
2191 			     sdev, ch->rq_size,
2192 			     ch->req_buf_cache, DMA_FROM_DEVICE);
2193 
2194 	srpt_cache_put(ch->req_buf_cache);
2195 
2196 	kref_put(&ch->kref, srpt_free_ch);
2197 }
2198 
2199 /**
2200  * srpt_cm_req_recv - process the event IB_CM_REQ_RECEIVED
2201  * @sdev: HCA through which the login request was received.
2202  * @ib_cm_id: IB/CM connection identifier in case of IB/CM.
2203  * @rdma_cm_id: RDMA/CM connection identifier in case of RDMA/CM.
2204  * @port_num: Port through which the REQ message was received.
2205  * @pkey: P_Key of the incoming connection.
2206  * @req: SRP login request.
2207  * @src_addr: GID (IB/CM) or IP address (RDMA/CM) of the port that submitted
2208  * the login request.
2209  *
2210  * Ownership of the cm_id is transferred to the target session if this
2211  * function returns zero. Otherwise the caller remains the owner of cm_id.
2212  */
2213 static int srpt_cm_req_recv(struct srpt_device *const sdev,
2214 			    struct ib_cm_id *ib_cm_id,
2215 			    struct rdma_cm_id *rdma_cm_id,
2216 			    u8 port_num, __be16 pkey,
2217 			    const struct srp_login_req *req,
2218 			    const char *src_addr)
2219 {
2220 	struct srpt_port *sport = &sdev->port[port_num - 1];
2221 	struct srpt_nexus *nexus;
2222 	struct srp_login_rsp *rsp = NULL;
2223 	struct srp_login_rej *rej = NULL;
2224 	union {
2225 		struct rdma_conn_param rdma_cm;
2226 		struct ib_cm_rep_param ib_cm;
2227 	} *rep_param = NULL;
2228 	struct srpt_rdma_ch *ch = NULL;
2229 	char i_port_id[36];
2230 	u32 it_iu_len;
2231 	int i, tag_num, tag_size, ret;
2232 	struct srpt_tpg *stpg;
2233 
2234 	WARN_ON_ONCE(irqs_disabled());
2235 
2236 	it_iu_len = be32_to_cpu(req->req_it_iu_len);
2237 
2238 	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",
2239 		req->initiator_port_id, req->target_port_id, it_iu_len,
2240 		port_num, &sport->gid, be16_to_cpu(pkey));
2241 
2242 	nexus = srpt_get_nexus(sport, req->initiator_port_id,
2243 			       req->target_port_id);
2244 	if (IS_ERR(nexus)) {
2245 		ret = PTR_ERR(nexus);
2246 		goto out;
2247 	}
2248 
2249 	ret = -ENOMEM;
2250 	rsp = kzalloc_obj(*rsp);
2251 	rej = kzalloc_obj(*rej);
2252 	rep_param = kzalloc_obj(*rep_param);
2253 	if (!rsp || !rej || !rep_param)
2254 		goto out;
2255 
2256 	ret = -EINVAL;
2257 	if (it_iu_len > srp_max_req_size || it_iu_len < 64) {
2258 		rej->reason = cpu_to_be32(
2259 				SRP_LOGIN_REJ_REQ_IT_IU_LENGTH_TOO_LARGE);
2260 		pr_err("rejected SRP_LOGIN_REQ because its length (%d bytes) is out of range (%d .. %d)\n",
2261 		       it_iu_len, 64, srp_max_req_size);
2262 		goto reject;
2263 	}
2264 
2265 	if (!sport->enabled) {
2266 		rej->reason = cpu_to_be32(SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
2267 		pr_info("rejected SRP_LOGIN_REQ because target port %s_%d has not yet been enabled\n",
2268 			dev_name(&sport->sdev->device->dev), port_num);
2269 		goto reject;
2270 	}
2271 
2272 	if (*(__be64 *)req->target_port_id != cpu_to_be64(srpt_service_guid)
2273 	    || *(__be64 *)(req->target_port_id + 8) !=
2274 	       cpu_to_be64(srpt_service_guid)) {
2275 		rej->reason = cpu_to_be32(
2276 				SRP_LOGIN_REJ_UNABLE_ASSOCIATE_CHANNEL);
2277 		pr_err("rejected SRP_LOGIN_REQ because it has an invalid target port identifier.\n");
2278 		goto reject;
2279 	}
2280 
2281 	ret = -ENOMEM;
2282 	ch = kzalloc_obj(*ch);
2283 	if (!ch) {
2284 		rej->reason = cpu_to_be32(SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
2285 		pr_err("rejected SRP_LOGIN_REQ because out of memory.\n");
2286 		goto reject;
2287 	}
2288 
2289 	kref_init(&ch->kref);
2290 	ch->pkey = be16_to_cpu(pkey);
2291 	ch->nexus = nexus;
2292 	ch->zw_cqe.done = srpt_zerolength_write_done;
2293 	INIT_WORK(&ch->release_work, srpt_release_channel_work);
2294 	ch->sport = sport;
2295 	if (rdma_cm_id) {
2296 		ch->using_rdma_cm = true;
2297 		ch->rdma_cm.cm_id = rdma_cm_id;
2298 		rdma_cm_id->context = ch;
2299 	} else {
2300 		ch->ib_cm.cm_id = ib_cm_id;
2301 		ib_cm_id->context = ch;
2302 	}
2303 	/*
2304 	 * ch->rq_size should be at least as large as the initiator queue
2305 	 * depth to avoid that the initiator driver has to report QUEUE_FULL
2306 	 * to the SCSI mid-layer.
2307 	 */
2308 	ch->rq_size = min(sdev->device->attrs.max_qp_wr, MAX_SRPT_RQ_SIZE);
2309 	spin_lock_init(&ch->spinlock);
2310 	ch->state = CH_CONNECTING;
2311 	INIT_LIST_HEAD(&ch->cmd_wait_list);
2312 	ch->max_rsp_size = ch->sport->port_attrib.srp_max_rsp_size;
2313 
2314 	ch->rsp_buf_cache = srpt_cache_get(ch->max_rsp_size);
2315 	if (!ch->rsp_buf_cache)
2316 		goto free_ch;
2317 
2318 	ch->ioctx_ring = (struct srpt_send_ioctx **)
2319 		srpt_alloc_ioctx_ring(ch->sport->sdev, ch->rq_size,
2320 				      sizeof(*ch->ioctx_ring[0]),
2321 				      ch->rsp_buf_cache, 0, DMA_TO_DEVICE);
2322 	if (!ch->ioctx_ring) {
2323 		pr_err("rejected SRP_LOGIN_REQ because creating a new QP SQ ring failed.\n");
2324 		rej->reason = cpu_to_be32(SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
2325 		goto free_rsp_cache;
2326 	}
2327 
2328 	for (i = 0; i < ch->rq_size; i++)
2329 		ch->ioctx_ring[i]->ch = ch;
2330 	if (!sdev->use_srq) {
2331 		u16 imm_data_offset = req->req_flags & SRP_IMMED_REQUESTED ?
2332 			be16_to_cpu(req->imm_data_offset) : 0;
2333 		u16 alignment_offset;
2334 		u32 req_sz;
2335 
2336 		if (req->req_flags & SRP_IMMED_REQUESTED)
2337 			pr_debug("imm_data_offset = %d\n",
2338 				 be16_to_cpu(req->imm_data_offset));
2339 		if (imm_data_offset >= sizeof(struct srp_cmd)) {
2340 			ch->imm_data_offset = imm_data_offset;
2341 			rsp->rsp_flags |= SRP_LOGIN_RSP_IMMED_SUPP;
2342 		} else {
2343 			ch->imm_data_offset = 0;
2344 		}
2345 		alignment_offset = round_up(imm_data_offset, 512) -
2346 			imm_data_offset;
2347 		req_sz = alignment_offset + imm_data_offset + srp_max_req_size;
2348 		ch->req_buf_cache = srpt_cache_get(req_sz);
2349 		if (!ch->req_buf_cache)
2350 			goto free_rsp_ring;
2351 
2352 		ch->ioctx_recv_ring = (struct srpt_recv_ioctx **)
2353 			srpt_alloc_ioctx_ring(ch->sport->sdev, ch->rq_size,
2354 					      sizeof(*ch->ioctx_recv_ring[0]),
2355 					      ch->req_buf_cache,
2356 					      alignment_offset,
2357 					      DMA_FROM_DEVICE);
2358 		if (!ch->ioctx_recv_ring) {
2359 			pr_err("rejected SRP_LOGIN_REQ because creating a new QP RQ ring failed.\n");
2360 			rej->reason =
2361 			    cpu_to_be32(SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
2362 			goto free_recv_cache;
2363 		}
2364 		for (i = 0; i < ch->rq_size; i++)
2365 			INIT_LIST_HEAD(&ch->ioctx_recv_ring[i]->wait_list);
2366 	}
2367 
2368 	ret = srpt_create_ch_ib(ch);
2369 	if (ret) {
2370 		rej->reason = cpu_to_be32(SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
2371 		pr_err("rejected SRP_LOGIN_REQ because creating a new RDMA channel failed.\n");
2372 		goto free_recv_ring;
2373 	}
2374 
2375 	strscpy(ch->sess_name, src_addr, sizeof(ch->sess_name));
2376 	snprintf(i_port_id, sizeof(i_port_id), "0x%016llx%016llx",
2377 			be64_to_cpu(*(__be64 *)nexus->i_port_id),
2378 			be64_to_cpu(*(__be64 *)(nexus->i_port_id + 8)));
2379 
2380 	pr_debug("registering src addr %s or i_port_id %s\n", ch->sess_name,
2381 		 i_port_id);
2382 
2383 	tag_num = ch->rq_size;
2384 	tag_size = 1; /* ib_srpt does not use se_sess->sess_cmd_map */
2385 
2386 	if (sport->guid_id) {
2387 		mutex_lock(&sport->guid_id->mutex);
2388 		list_for_each_entry(stpg, &sport->guid_id->tpg_list, entry) {
2389 			if (!IS_ERR_OR_NULL(ch->sess))
2390 				break;
2391 			ch->sess = target_setup_session(&stpg->tpg, tag_num,
2392 						tag_size, TARGET_PROT_NORMAL,
2393 						ch->sess_name, ch, NULL);
2394 		}
2395 		mutex_unlock(&sport->guid_id->mutex);
2396 	}
2397 
2398 	if (sport->gid_id) {
2399 		mutex_lock(&sport->gid_id->mutex);
2400 		list_for_each_entry(stpg, &sport->gid_id->tpg_list, entry) {
2401 			if (!IS_ERR_OR_NULL(ch->sess))
2402 				break;
2403 			ch->sess = target_setup_session(&stpg->tpg, tag_num,
2404 					tag_size, TARGET_PROT_NORMAL, i_port_id,
2405 					ch, NULL);
2406 			if (!IS_ERR_OR_NULL(ch->sess))
2407 				break;
2408 			/* Retry without leading "0x" */
2409 			ch->sess = target_setup_session(&stpg->tpg, tag_num,
2410 						tag_size, TARGET_PROT_NORMAL,
2411 						i_port_id + 2, ch, NULL);
2412 		}
2413 		mutex_unlock(&sport->gid_id->mutex);
2414 	}
2415 
2416 	if (IS_ERR_OR_NULL(ch->sess)) {
2417 		WARN_ON_ONCE(ch->sess == NULL);
2418 		ret = PTR_ERR(ch->sess);
2419 		ch->sess = NULL;
2420 		pr_info("Rejected login for initiator %s: ret = %d.\n",
2421 			ch->sess_name, ret);
2422 		rej->reason = cpu_to_be32(ret == -ENOMEM ?
2423 				SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES :
2424 				SRP_LOGIN_REJ_CHANNEL_LIMIT_REACHED);
2425 		goto destroy_ib;
2426 	}
2427 
2428 	/*
2429 	 * Once a session has been created destruction of srpt_rdma_ch objects
2430 	 * will decrement sport->refcount. Hence increment sport->refcount now.
2431 	 */
2432 	atomic_inc(&sport->refcount);
2433 
2434 	mutex_lock(&sport->mutex);
2435 
2436 	if ((req->req_flags & SRP_MTCH_ACTION) == SRP_MULTICHAN_SINGLE) {
2437 		struct srpt_rdma_ch *ch2;
2438 
2439 		list_for_each_entry(ch2, &nexus->ch_list, list) {
2440 			if (srpt_disconnect_ch(ch2) < 0)
2441 				continue;
2442 			pr_info("Relogin - closed existing channel %s\n",
2443 				ch2->sess_name);
2444 			rsp->rsp_flags |= SRP_LOGIN_RSP_MULTICHAN_TERMINATED;
2445 		}
2446 	} else {
2447 		rsp->rsp_flags |= SRP_LOGIN_RSP_MULTICHAN_MAINTAINED;
2448 	}
2449 
2450 	list_add_tail_rcu(&ch->list, &nexus->ch_list);
2451 
2452 	if (!sport->enabled) {
2453 		rej->reason = cpu_to_be32(
2454 				SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
2455 		pr_info("rejected SRP_LOGIN_REQ because target %s_%d is not enabled\n",
2456 			dev_name(&sdev->device->dev), port_num);
2457 		mutex_unlock(&sport->mutex);
2458 		ret = -EINVAL;
2459 		goto reject;
2460 	}
2461 
2462 	mutex_unlock(&sport->mutex);
2463 
2464 	ret = ch->using_rdma_cm ? 0 : srpt_ch_qp_rtr(ch, ch->qp);
2465 	if (ret) {
2466 		rej->reason = cpu_to_be32(SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
2467 		pr_err("rejected SRP_LOGIN_REQ because enabling RTR failed (error code = %d)\n",
2468 		       ret);
2469 		goto reject;
2470 	}
2471 
2472 	pr_debug("Establish connection sess=%p name=%s ch=%p\n", ch->sess,
2473 		 ch->sess_name, ch);
2474 
2475 	/* create srp_login_response */
2476 	rsp->opcode = SRP_LOGIN_RSP;
2477 	rsp->tag = req->tag;
2478 	rsp->max_it_iu_len = cpu_to_be32(srp_max_req_size);
2479 	rsp->max_ti_iu_len = req->req_it_iu_len;
2480 	ch->max_ti_iu_len = it_iu_len;
2481 	rsp->buf_fmt = cpu_to_be16(SRP_BUF_FORMAT_DIRECT |
2482 				   SRP_BUF_FORMAT_INDIRECT);
2483 	rsp->req_lim_delta = cpu_to_be32(ch->rq_size);
2484 	atomic_set(&ch->req_lim, ch->rq_size);
2485 	atomic_set(&ch->req_lim_delta, 0);
2486 
2487 	/* create cm reply */
2488 	if (ch->using_rdma_cm) {
2489 		rep_param->rdma_cm.private_data = (void *)rsp;
2490 		rep_param->rdma_cm.private_data_len = sizeof(*rsp);
2491 		rep_param->rdma_cm.rnr_retry_count = 7;
2492 		rep_param->rdma_cm.flow_control = 1;
2493 		rep_param->rdma_cm.responder_resources = 4;
2494 		rep_param->rdma_cm.initiator_depth = 4;
2495 	} else {
2496 		rep_param->ib_cm.qp_num = ch->qp->qp_num;
2497 		rep_param->ib_cm.private_data = (void *)rsp;
2498 		rep_param->ib_cm.private_data_len = sizeof(*rsp);
2499 		rep_param->ib_cm.rnr_retry_count = 7;
2500 		rep_param->ib_cm.flow_control = 1;
2501 		rep_param->ib_cm.failover_accepted = 0;
2502 		rep_param->ib_cm.srq = 1;
2503 		rep_param->ib_cm.responder_resources = 4;
2504 		rep_param->ib_cm.initiator_depth = 4;
2505 	}
2506 
2507 	/*
2508 	 * Hold the sport mutex while accepting a connection to avoid that
2509 	 * srpt_disconnect_ch() is invoked concurrently with this code.
2510 	 */
2511 	mutex_lock(&sport->mutex);
2512 	if (sport->enabled && ch->state == CH_CONNECTING) {
2513 		if (ch->using_rdma_cm)
2514 			ret = rdma_accept(rdma_cm_id, &rep_param->rdma_cm);
2515 		else
2516 			ret = ib_send_cm_rep(ib_cm_id, &rep_param->ib_cm);
2517 	} else {
2518 		ret = -EINVAL;
2519 	}
2520 	mutex_unlock(&sport->mutex);
2521 
2522 	switch (ret) {
2523 	case 0:
2524 		break;
2525 	case -EINVAL:
2526 		goto reject;
2527 	default:
2528 		rej->reason = cpu_to_be32(SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
2529 		pr_err("sending SRP_LOGIN_REQ response failed (error code = %d)\n",
2530 		       ret);
2531 		goto reject;
2532 	}
2533 
2534 	goto out;
2535 
2536 destroy_ib:
2537 	srpt_destroy_ch_ib(ch);
2538 
2539 free_recv_ring:
2540 	srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_recv_ring,
2541 			     ch->sport->sdev, ch->rq_size,
2542 			     ch->req_buf_cache, DMA_FROM_DEVICE);
2543 
2544 free_recv_cache:
2545 	srpt_cache_put(ch->req_buf_cache);
2546 
2547 free_rsp_ring:
2548 	srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_ring,
2549 			     ch->sport->sdev, ch->rq_size,
2550 			     ch->rsp_buf_cache, DMA_TO_DEVICE);
2551 
2552 free_rsp_cache:
2553 	srpt_cache_put(ch->rsp_buf_cache);
2554 
2555 free_ch:
2556 	if (rdma_cm_id)
2557 		rdma_cm_id->context = NULL;
2558 	else
2559 		ib_cm_id->context = NULL;
2560 	kfree(ch);
2561 	ch = NULL;
2562 
2563 	WARN_ON_ONCE(ret == 0);
2564 
2565 reject:
2566 	pr_info("Rejecting login with reason %#x\n", be32_to_cpu(rej->reason));
2567 	rej->opcode = SRP_LOGIN_REJ;
2568 	rej->tag = req->tag;
2569 	rej->buf_fmt = cpu_to_be16(SRP_BUF_FORMAT_DIRECT |
2570 				   SRP_BUF_FORMAT_INDIRECT);
2571 
2572 	if (rdma_cm_id)
2573 		rdma_reject(rdma_cm_id, rej, sizeof(*rej),
2574 			    IB_CM_REJ_CONSUMER_DEFINED);
2575 	else
2576 		ib_send_cm_rej(ib_cm_id, IB_CM_REJ_CONSUMER_DEFINED, NULL, 0,
2577 			       rej, sizeof(*rej));
2578 
2579 	if (ch && ch->sess) {
2580 		srpt_close_ch(ch);
2581 		/*
2582 		 * Tell the caller not to free cm_id since
2583 		 * srpt_release_channel_work() will do that.
2584 		 */
2585 		ret = 0;
2586 	}
2587 
2588 out:
2589 	kfree(rep_param);
2590 	kfree(rsp);
2591 	kfree(rej);
2592 
2593 	return ret;
2594 }
2595 
2596 static int srpt_ib_cm_req_recv(struct ib_cm_id *cm_id,
2597 			       const struct ib_cm_req_event_param *param,
2598 			       void *private_data)
2599 {
2600 	char sguid[40];
2601 
2602 	srpt_format_guid(sguid, sizeof(sguid),
2603 			 &param->primary_path->dgid.global.interface_id);
2604 
2605 	return srpt_cm_req_recv(cm_id->context, cm_id, NULL, param->port,
2606 				param->primary_path->pkey,
2607 				private_data, sguid);
2608 }
2609 
2610 static int srpt_rdma_cm_req_recv(struct rdma_cm_id *cm_id,
2611 				 struct rdma_cm_event *event)
2612 {
2613 	struct srpt_device *sdev;
2614 	struct srp_login_req req;
2615 	const struct srp_login_req_rdma *req_rdma;
2616 	struct sa_path_rec *path_rec = cm_id->route.path_rec;
2617 	char src_addr[40];
2618 
2619 	sdev = ib_get_client_data(cm_id->device, &srpt_client);
2620 	if (!sdev)
2621 		return -ECONNREFUSED;
2622 
2623 	if (event->param.conn.private_data_len < sizeof(*req_rdma))
2624 		return -EINVAL;
2625 
2626 	/* Transform srp_login_req_rdma into srp_login_req. */
2627 	req_rdma = event->param.conn.private_data;
2628 	memset(&req, 0, sizeof(req));
2629 	req.opcode		= req_rdma->opcode;
2630 	req.tag			= req_rdma->tag;
2631 	req.req_it_iu_len	= req_rdma->req_it_iu_len;
2632 	req.req_buf_fmt		= req_rdma->req_buf_fmt;
2633 	req.req_flags		= req_rdma->req_flags;
2634 	memcpy(req.initiator_port_id, req_rdma->initiator_port_id, 16);
2635 	memcpy(req.target_port_id, req_rdma->target_port_id, 16);
2636 	req.imm_data_offset	= req_rdma->imm_data_offset;
2637 
2638 	snprintf(src_addr, sizeof(src_addr), "%pIS",
2639 		 &cm_id->route.addr.src_addr);
2640 
2641 	return srpt_cm_req_recv(sdev, NULL, cm_id, cm_id->port_num,
2642 				path_rec ? path_rec->pkey : 0, &req, src_addr);
2643 }
2644 
2645 static void srpt_cm_rej_recv(struct srpt_rdma_ch *ch,
2646 			     enum ib_cm_rej_reason reason,
2647 			     const u8 *private_data,
2648 			     u8 private_data_len)
2649 {
2650 	char *priv = NULL;
2651 	int i;
2652 
2653 	if (private_data_len && (priv = kmalloc(private_data_len * 3 + 1,
2654 						GFP_KERNEL))) {
2655 		for (i = 0; i < private_data_len; i++)
2656 			sprintf(priv + 3 * i, " %02x", private_data[i]);
2657 	}
2658 	pr_info("Received CM REJ for ch %s-%d; reason %d%s%s.\n",
2659 		ch->sess_name, ch->qp->qp_num, reason, private_data_len ?
2660 		"; private data" : "", priv ? priv : " (?)");
2661 	kfree(priv);
2662 }
2663 
2664 /**
2665  * srpt_cm_rtu_recv - process an IB_CM_RTU_RECEIVED or USER_ESTABLISHED event
2666  * @ch: SRPT RDMA channel.
2667  *
2668  * An RTU (ready to use) message indicates that the connection has been
2669  * established and that the recipient may begin transmitting.
2670  */
2671 static void srpt_cm_rtu_recv(struct srpt_rdma_ch *ch)
2672 {
2673 	int ret;
2674 
2675 	ret = ch->using_rdma_cm ? 0 : srpt_ch_qp_rts(ch, ch->qp);
2676 	if (ret < 0) {
2677 		pr_err("%s-%d: QP transition to RTS failed\n", ch->sess_name,
2678 		       ch->qp->qp_num);
2679 		srpt_close_ch(ch);
2680 		return;
2681 	}
2682 
2683 	/*
2684 	 * Note: calling srpt_close_ch() if the transition to the LIVE state
2685 	 * fails is not necessary since that means that that function has
2686 	 * already been invoked from another thread.
2687 	 */
2688 	if (!srpt_set_ch_state(ch, CH_LIVE)) {
2689 		pr_err("%s-%d: channel transition to LIVE state failed\n",
2690 		       ch->sess_name, ch->qp->qp_num);
2691 		return;
2692 	}
2693 
2694 	/* Trigger wait list processing. */
2695 	ret = srpt_zerolength_write(ch);
2696 	WARN_ONCE(ret < 0, "%d\n", ret);
2697 }
2698 
2699 /**
2700  * srpt_cm_handler - IB connection manager callback function
2701  * @cm_id: IB/CM connection identifier.
2702  * @event: IB/CM event.
2703  *
2704  * A non-zero return value will cause the caller destroy the CM ID.
2705  *
2706  * Note: srpt_cm_handler() must only return a non-zero value when transferring
2707  * ownership of the cm_id to a channel by srpt_cm_req_recv() failed. Returning
2708  * a non-zero value in any other case will trigger a race with the
2709  * ib_destroy_cm_id() call in srpt_release_channel().
2710  */
2711 static int srpt_cm_handler(struct ib_cm_id *cm_id,
2712 			   const struct ib_cm_event *event)
2713 {
2714 	struct srpt_rdma_ch *ch = cm_id->context;
2715 	int ret;
2716 
2717 	ret = 0;
2718 	switch (event->event) {
2719 	case IB_CM_REQ_RECEIVED:
2720 		ret = srpt_ib_cm_req_recv(cm_id, &event->param.req_rcvd,
2721 					  event->private_data);
2722 		break;
2723 	case IB_CM_REJ_RECEIVED:
2724 		srpt_cm_rej_recv(ch, event->param.rej_rcvd.reason,
2725 				 event->private_data,
2726 				 IB_CM_REJ_PRIVATE_DATA_SIZE);
2727 		break;
2728 	case IB_CM_RTU_RECEIVED:
2729 	case IB_CM_USER_ESTABLISHED:
2730 		srpt_cm_rtu_recv(ch);
2731 		break;
2732 	case IB_CM_DREQ_RECEIVED:
2733 		srpt_disconnect_ch(ch);
2734 		break;
2735 	case IB_CM_DREP_RECEIVED:
2736 		pr_info("Received CM DREP message for ch %s-%d.\n",
2737 			ch->sess_name, ch->qp->qp_num);
2738 		srpt_close_ch(ch);
2739 		break;
2740 	case IB_CM_TIMEWAIT_EXIT:
2741 		pr_info("Received CM TimeWait exit for ch %s-%d.\n",
2742 			ch->sess_name, ch->qp->qp_num);
2743 		srpt_close_ch(ch);
2744 		break;
2745 	case IB_CM_REP_ERROR:
2746 		pr_info("Received CM REP error for ch %s-%d.\n", ch->sess_name,
2747 			ch->qp->qp_num);
2748 		break;
2749 	case IB_CM_DREQ_ERROR:
2750 		pr_info("Received CM DREQ ERROR event.\n");
2751 		break;
2752 	case IB_CM_MRA_RECEIVED:
2753 		pr_info("Received CM MRA event\n");
2754 		break;
2755 	default:
2756 		pr_err("received unrecognized CM event %d\n", event->event);
2757 		break;
2758 	}
2759 
2760 	return ret;
2761 }
2762 
2763 static int srpt_rdma_cm_handler(struct rdma_cm_id *cm_id,
2764 				struct rdma_cm_event *event)
2765 {
2766 	struct srpt_rdma_ch *ch = cm_id->context;
2767 	int ret = 0;
2768 
2769 	switch (event->event) {
2770 	case RDMA_CM_EVENT_CONNECT_REQUEST:
2771 		ret = srpt_rdma_cm_req_recv(cm_id, event);
2772 		break;
2773 	case RDMA_CM_EVENT_REJECTED:
2774 		srpt_cm_rej_recv(ch, event->status,
2775 				 event->param.conn.private_data,
2776 				 event->param.conn.private_data_len);
2777 		break;
2778 	case RDMA_CM_EVENT_ESTABLISHED:
2779 		srpt_cm_rtu_recv(ch);
2780 		break;
2781 	case RDMA_CM_EVENT_DISCONNECTED:
2782 		if (ch->state < CH_DISCONNECTING)
2783 			srpt_disconnect_ch(ch);
2784 		else
2785 			srpt_close_ch(ch);
2786 		break;
2787 	case RDMA_CM_EVENT_TIMEWAIT_EXIT:
2788 		srpt_close_ch(ch);
2789 		break;
2790 	case RDMA_CM_EVENT_UNREACHABLE:
2791 		pr_info("Received CM REP error for ch %s-%d.\n", ch->sess_name,
2792 			ch->qp->qp_num);
2793 		break;
2794 	case RDMA_CM_EVENT_DEVICE_REMOVAL:
2795 	case RDMA_CM_EVENT_ADDR_CHANGE:
2796 		break;
2797 	default:
2798 		pr_err("received unrecognized RDMA CM event %d\n",
2799 		       event->event);
2800 		break;
2801 	}
2802 
2803 	return ret;
2804 }
2805 
2806 /*
2807  * srpt_write_pending - Start data transfer from initiator to target (write).
2808  */
2809 static int srpt_write_pending(struct se_cmd *se_cmd)
2810 {
2811 	struct srpt_send_ioctx *ioctx =
2812 		container_of(se_cmd, struct srpt_send_ioctx, cmd);
2813 	struct srpt_rdma_ch *ch = ioctx->ch;
2814 	struct ib_send_wr *first_wr = NULL;
2815 	struct ib_cqe *cqe = &ioctx->rdma_cqe;
2816 	enum srpt_command_state new_state;
2817 	int ret, i;
2818 
2819 	if (ioctx->recv_ioctx) {
2820 		srpt_set_cmd_state(ioctx, SRPT_STATE_DATA_IN);
2821 		target_execute_cmd(&ioctx->cmd);
2822 		return 0;
2823 	}
2824 
2825 	new_state = srpt_set_cmd_state(ioctx, SRPT_STATE_NEED_DATA);
2826 	WARN_ON(new_state == SRPT_STATE_DONE);
2827 
2828 	if (atomic_sub_return(ioctx->n_rdma, &ch->sq_wr_avail) < 0) {
2829 		pr_warn("%s: IB send queue full (needed %d)\n",
2830 				__func__, ioctx->n_rdma);
2831 		ret = -ENOMEM;
2832 		goto out_undo;
2833 	}
2834 
2835 	cqe->done = srpt_rdma_read_done;
2836 	for (i = ioctx->n_rw_ctx - 1; i >= 0; i--) {
2837 		struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
2838 
2839 		first_wr = rdma_rw_ctx_wrs(&ctx->rw, ch->qp, ch->sport->port,
2840 				cqe, first_wr);
2841 		cqe = NULL;
2842 	}
2843 
2844 	ret = ib_post_send(ch->qp, first_wr, NULL);
2845 	if (ret) {
2846 		pr_err("%s: ib_post_send() returned %d for %d (avail: %d)\n",
2847 			 __func__, ret, ioctx->n_rdma,
2848 			 atomic_read(&ch->sq_wr_avail));
2849 		goto out_undo;
2850 	}
2851 
2852 	return 0;
2853 out_undo:
2854 	atomic_add(ioctx->n_rdma, &ch->sq_wr_avail);
2855 	return ret;
2856 }
2857 
2858 static u8 tcm_to_srp_tsk_mgmt_status(const int tcm_mgmt_status)
2859 {
2860 	switch (tcm_mgmt_status) {
2861 	case TMR_FUNCTION_COMPLETE:
2862 		return SRP_TSK_MGMT_SUCCESS;
2863 	case TMR_FUNCTION_REJECTED:
2864 		return SRP_TSK_MGMT_FUNC_NOT_SUPP;
2865 	}
2866 	return SRP_TSK_MGMT_FAILED;
2867 }
2868 
2869 /**
2870  * srpt_queue_response - transmit the response to a SCSI command
2871  * @cmd: SCSI target command.
2872  *
2873  * Callback function called by the TCM core. Must not block since it can be
2874  * invoked on the context of the IB completion handler.
2875  */
2876 static void srpt_queue_response(struct se_cmd *cmd)
2877 {
2878 	struct srpt_send_ioctx *ioctx =
2879 		container_of(cmd, struct srpt_send_ioctx, cmd);
2880 	struct srpt_rdma_ch *ch = ioctx->ch;
2881 	struct srpt_device *sdev = ch->sport->sdev;
2882 	struct ib_send_wr send_wr, *first_wr = &send_wr;
2883 	struct ib_sge sge;
2884 	enum srpt_command_state state;
2885 	int resp_len, ret, i;
2886 	u8 srp_tm_status;
2887 
2888 	state = ioctx->state;
2889 	switch (state) {
2890 	case SRPT_STATE_NEW:
2891 	case SRPT_STATE_DATA_IN:
2892 		ioctx->state = SRPT_STATE_CMD_RSP_SENT;
2893 		break;
2894 	case SRPT_STATE_MGMT:
2895 		ioctx->state = SRPT_STATE_MGMT_RSP_SENT;
2896 		break;
2897 	default:
2898 		WARN(true, "ch %p; cmd %d: unexpected command state %d\n",
2899 			ch, ioctx->ioctx.index, ioctx->state);
2900 		break;
2901 	}
2902 
2903 	if (WARN_ON_ONCE(state == SRPT_STATE_CMD_RSP_SENT))
2904 		return;
2905 
2906 	/* For read commands, transfer the data to the initiator. */
2907 	if (ioctx->cmd.data_direction == DMA_FROM_DEVICE &&
2908 	    ioctx->cmd.data_length &&
2909 	    !ioctx->queue_status_only) {
2910 		for (i = ioctx->n_rw_ctx - 1; i >= 0; i--) {
2911 			struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
2912 
2913 			first_wr = rdma_rw_ctx_wrs(&ctx->rw, ch->qp,
2914 					ch->sport->port, NULL, first_wr);
2915 		}
2916 	}
2917 
2918 	if (state != SRPT_STATE_MGMT)
2919 		resp_len = srpt_build_cmd_rsp(ch, ioctx, ioctx->cmd.tag,
2920 					      cmd->scsi_status);
2921 	else {
2922 		srp_tm_status
2923 			= tcm_to_srp_tsk_mgmt_status(cmd->se_tmr_req->response);
2924 		resp_len = srpt_build_tskmgmt_rsp(ch, ioctx, srp_tm_status,
2925 						 ioctx->cmd.tag);
2926 	}
2927 
2928 	atomic_inc(&ch->req_lim);
2929 
2930 	if (unlikely(atomic_sub_return(1 + ioctx->n_rdma,
2931 			&ch->sq_wr_avail) < 0)) {
2932 		pr_warn("%s: IB send queue full (needed %d)\n",
2933 				__func__, ioctx->n_rdma);
2934 		goto out;
2935 	}
2936 
2937 	ib_dma_sync_single_for_device(sdev->device, ioctx->ioctx.dma, resp_len,
2938 				      DMA_TO_DEVICE);
2939 
2940 	sge.addr = ioctx->ioctx.dma;
2941 	sge.length = resp_len;
2942 	sge.lkey = sdev->lkey;
2943 
2944 	ioctx->ioctx.cqe.done = srpt_send_done;
2945 	send_wr.next = NULL;
2946 	send_wr.wr_cqe = &ioctx->ioctx.cqe;
2947 	send_wr.sg_list = &sge;
2948 	send_wr.num_sge = 1;
2949 	send_wr.opcode = IB_WR_SEND;
2950 	send_wr.send_flags = IB_SEND_SIGNALED;
2951 
2952 	ret = ib_post_send(ch->qp, first_wr, NULL);
2953 	if (ret < 0) {
2954 		pr_err("%s: sending cmd response failed for tag %llu (%d)\n",
2955 			__func__, ioctx->cmd.tag, ret);
2956 		goto out;
2957 	}
2958 
2959 	return;
2960 
2961 out:
2962 	atomic_add(1 + ioctx->n_rdma, &ch->sq_wr_avail);
2963 	atomic_dec(&ch->req_lim);
2964 	srpt_set_cmd_state(ioctx, SRPT_STATE_DONE);
2965 	target_put_sess_cmd(&ioctx->cmd);
2966 }
2967 
2968 static int srpt_queue_data_in(struct se_cmd *cmd)
2969 {
2970 	srpt_queue_response(cmd);
2971 	return 0;
2972 }
2973 
2974 static void srpt_queue_tm_rsp(struct se_cmd *cmd)
2975 {
2976 	srpt_queue_response(cmd);
2977 }
2978 
2979 /*
2980  * This function is called for aborted commands if no response is sent to the
2981  * initiator. Make sure that the credits freed by aborting a command are
2982  * returned to the initiator the next time a response is sent by incrementing
2983  * ch->req_lim_delta.
2984  */
2985 static void srpt_aborted_task(struct se_cmd *cmd)
2986 {
2987 	struct srpt_send_ioctx *ioctx = container_of(cmd,
2988 				struct srpt_send_ioctx, cmd);
2989 	struct srpt_rdma_ch *ch = ioctx->ch;
2990 
2991 	atomic_inc(&ch->req_lim_delta);
2992 }
2993 
2994 static int srpt_queue_status(struct se_cmd *cmd)
2995 {
2996 	struct srpt_send_ioctx *ioctx;
2997 
2998 	ioctx = container_of(cmd, struct srpt_send_ioctx, cmd);
2999 	BUG_ON(ioctx->sense_data != cmd->sense_buffer);
3000 	if (cmd->se_cmd_flags &
3001 	    (SCF_TRANSPORT_TASK_SENSE | SCF_EMULATED_TASK_SENSE))
3002 		WARN_ON(cmd->scsi_status != SAM_STAT_CHECK_CONDITION);
3003 	ioctx->queue_status_only = true;
3004 	srpt_queue_response(cmd);
3005 	return 0;
3006 }
3007 
3008 static void srpt_refresh_port_work(struct work_struct *work)
3009 {
3010 	struct srpt_port *sport = container_of(work, struct srpt_port, work);
3011 
3012 	srpt_refresh_port(sport);
3013 }
3014 
3015 /**
3016  * srpt_release_sport - disable login and wait for associated channels
3017  * @sport: SRPT HCA port.
3018  */
3019 static int srpt_release_sport(struct srpt_port *sport)
3020 {
3021 	DECLARE_COMPLETION_ONSTACK(c);
3022 	struct srpt_nexus *nexus, *next_n;
3023 	struct srpt_rdma_ch *ch;
3024 
3025 	WARN_ON_ONCE(irqs_disabled());
3026 
3027 	sport->freed_channels = &c;
3028 
3029 	mutex_lock(&sport->mutex);
3030 	srpt_set_enabled(sport, false);
3031 	mutex_unlock(&sport->mutex);
3032 
3033 	while (atomic_read(&sport->refcount) > 0 &&
3034 	       wait_for_completion_timeout(&c, 5 * HZ) <= 0) {
3035 		pr_info("%s_%d: waiting for unregistration of %d sessions ...\n",
3036 			dev_name(&sport->sdev->device->dev), sport->port,
3037 			atomic_read(&sport->refcount));
3038 		rcu_read_lock();
3039 		list_for_each_entry(nexus, &sport->nexus_list, entry) {
3040 			list_for_each_entry(ch, &nexus->ch_list, list) {
3041 				pr_info("%s-%d: state %s\n",
3042 					ch->sess_name, ch->qp->qp_num,
3043 					get_ch_state_name(ch->state));
3044 			}
3045 		}
3046 		rcu_read_unlock();
3047 	}
3048 
3049 	mutex_lock(&sport->mutex);
3050 	list_for_each_entry_safe(nexus, next_n, &sport->nexus_list, entry) {
3051 		list_del(&nexus->entry);
3052 		kfree_rcu(nexus, rcu);
3053 	}
3054 	mutex_unlock(&sport->mutex);
3055 
3056 	return 0;
3057 }
3058 
3059 struct port_and_port_id {
3060 	struct srpt_port *sport;
3061 	struct srpt_port_id **port_id;
3062 };
3063 
3064 static struct port_and_port_id __srpt_lookup_port(const char *name)
3065 {
3066 	struct ib_device *dev;
3067 	struct srpt_device *sdev;
3068 	struct srpt_port *sport;
3069 	int i;
3070 
3071 	list_for_each_entry(sdev, &srpt_dev_list, list) {
3072 		dev = sdev->device;
3073 		if (!dev)
3074 			continue;
3075 
3076 		for (i = 0; i < dev->phys_port_cnt; i++) {
3077 			sport = &sdev->port[i];
3078 
3079 			if (strcmp(sport->guid_name, name) == 0) {
3080 				kref_get(&sdev->refcnt);
3081 				return (struct port_and_port_id){
3082 					sport, &sport->guid_id};
3083 			}
3084 			if (strcmp(sport->gid_name, name) == 0) {
3085 				kref_get(&sdev->refcnt);
3086 				return (struct port_and_port_id){
3087 					sport, &sport->gid_id};
3088 			}
3089 		}
3090 	}
3091 
3092 	return (struct port_and_port_id){};
3093 }
3094 
3095 /**
3096  * srpt_lookup_port() - Look up an RDMA port by name
3097  * @name: ASCII port name
3098  *
3099  * Increments the RDMA port reference count if an RDMA port pointer is returned.
3100  * The caller must drop that reference count by calling srpt_port_put_ref().
3101  */
3102 static struct port_and_port_id srpt_lookup_port(const char *name)
3103 {
3104 	struct port_and_port_id papi;
3105 
3106 	spin_lock(&srpt_dev_lock);
3107 	papi = __srpt_lookup_port(name);
3108 	spin_unlock(&srpt_dev_lock);
3109 
3110 	return papi;
3111 }
3112 
3113 static void srpt_free_srq(struct srpt_device *sdev)
3114 {
3115 	if (!sdev->srq)
3116 		return;
3117 
3118 	ib_destroy_srq(sdev->srq);
3119 	srpt_free_ioctx_ring((struct srpt_ioctx **)sdev->ioctx_ring, sdev,
3120 			     sdev->srq_size, sdev->req_buf_cache,
3121 			     DMA_FROM_DEVICE);
3122 	srpt_cache_put(sdev->req_buf_cache);
3123 	sdev->srq = NULL;
3124 }
3125 
3126 static int srpt_alloc_srq(struct srpt_device *sdev)
3127 {
3128 	struct ib_srq_init_attr srq_attr = {
3129 		.event_handler = srpt_srq_event,
3130 		.srq_context = (void *)sdev,
3131 		.attr.max_wr = sdev->srq_size,
3132 		.attr.max_sge = 1,
3133 		.srq_type = IB_SRQT_BASIC,
3134 	};
3135 	struct ib_device *device = sdev->device;
3136 	struct ib_srq *srq;
3137 	int i;
3138 
3139 	WARN_ON_ONCE(sdev->srq);
3140 	srq = ib_create_srq(sdev->pd, &srq_attr);
3141 	if (IS_ERR(srq)) {
3142 		pr_debug("ib_create_srq() failed: %pe\n", srq);
3143 		return PTR_ERR(srq);
3144 	}
3145 
3146 	pr_debug("create SRQ #wr= %d max_allow=%u dev= %s\n", sdev->srq_size,
3147 		 sdev->device->attrs.max_srq_wr, dev_name(&device->dev));
3148 
3149 	sdev->req_buf_cache = srpt_cache_get(srp_max_req_size);
3150 	if (!sdev->req_buf_cache)
3151 		goto free_srq;
3152 
3153 	sdev->ioctx_ring = (struct srpt_recv_ioctx **)
3154 		srpt_alloc_ioctx_ring(sdev, sdev->srq_size,
3155 				      sizeof(*sdev->ioctx_ring[0]),
3156 				      sdev->req_buf_cache, 0, DMA_FROM_DEVICE);
3157 	if (!sdev->ioctx_ring)
3158 		goto free_cache;
3159 
3160 	sdev->use_srq = true;
3161 	sdev->srq = srq;
3162 
3163 	for (i = 0; i < sdev->srq_size; ++i) {
3164 		INIT_LIST_HEAD(&sdev->ioctx_ring[i]->wait_list);
3165 		srpt_post_recv(sdev, NULL, sdev->ioctx_ring[i]);
3166 	}
3167 
3168 	return 0;
3169 
3170 free_cache:
3171 	srpt_cache_put(sdev->req_buf_cache);
3172 
3173 free_srq:
3174 	ib_destroy_srq(srq);
3175 	return -ENOMEM;
3176 }
3177 
3178 static int srpt_use_srq(struct srpt_device *sdev, bool use_srq)
3179 {
3180 	struct ib_device *device = sdev->device;
3181 	int ret = 0;
3182 
3183 	if (!use_srq) {
3184 		srpt_free_srq(sdev);
3185 		sdev->use_srq = false;
3186 	} else if (use_srq && !sdev->srq) {
3187 		ret = srpt_alloc_srq(sdev);
3188 	}
3189 	pr_debug("%s(%s): use_srq = %d; ret = %d\n", __func__,
3190 		 dev_name(&device->dev), sdev->use_srq, ret);
3191 	return ret;
3192 }
3193 
3194 static void srpt_free_sdev(struct kref *refcnt)
3195 {
3196 	struct srpt_device *sdev = container_of(refcnt, typeof(*sdev), refcnt);
3197 
3198 	kfree(sdev);
3199 }
3200 
3201 static void srpt_sdev_put(struct srpt_device *sdev)
3202 {
3203 	kref_put(&sdev->refcnt, srpt_free_sdev);
3204 }
3205 
3206 /**
3207  * srpt_add_one - InfiniBand device addition callback function
3208  * @device: Describes a HCA.
3209  */
3210 static int srpt_add_one(struct ib_device *device)
3211 {
3212 	struct srpt_device *sdev;
3213 	struct srpt_port *sport;
3214 	int ret;
3215 	u32 i;
3216 
3217 	pr_debug("device = %p\n", device);
3218 
3219 	sdev = kzalloc_flex(*sdev, port, device->phys_port_cnt);
3220 	if (!sdev)
3221 		return -ENOMEM;
3222 
3223 	kref_init(&sdev->refcnt);
3224 	sdev->device = device;
3225 	mutex_init(&sdev->sdev_mutex);
3226 
3227 	sdev->pd = ib_alloc_pd(device, 0);
3228 	if (IS_ERR(sdev->pd)) {
3229 		ret = PTR_ERR(sdev->pd);
3230 		goto free_dev;
3231 	}
3232 
3233 	sdev->lkey = sdev->pd->local_dma_lkey;
3234 
3235 	sdev->srq_size = min(srpt_srq_size, sdev->device->attrs.max_srq_wr);
3236 
3237 	srpt_use_srq(sdev, sdev->port[0].port_attrib.use_srq);
3238 
3239 	if (!srpt_service_guid)
3240 		srpt_service_guid = be64_to_cpu(device->node_guid);
3241 
3242 	if (rdma_port_get_link_layer(device, 1) == IB_LINK_LAYER_INFINIBAND)
3243 		sdev->cm_id = ib_create_cm_id(device, srpt_cm_handler, sdev);
3244 	if (IS_ERR(sdev->cm_id)) {
3245 		pr_info("ib_create_cm_id() failed: %pe\n", sdev->cm_id);
3246 		ret = PTR_ERR(sdev->cm_id);
3247 		sdev->cm_id = NULL;
3248 		if (!rdma_cm_id)
3249 			goto err_ring;
3250 	}
3251 
3252 	/* print out target login information */
3253 	pr_debug("Target login info: id_ext=%016llx,ioc_guid=%016llx,pkey=ffff,service_id=%016llx\n",
3254 		 srpt_service_guid, srpt_service_guid, srpt_service_guid);
3255 
3256 	/*
3257 	 * We do not have a consistent service_id (ie. also id_ext of target_id)
3258 	 * to identify this target. We currently use the guid of the first HCA
3259 	 * in the system as service_id; therefore, the target_id will change
3260 	 * if this HCA is gone bad and replaced by different HCA
3261 	 */
3262 	ret = sdev->cm_id ?
3263 		ib_cm_listen(sdev->cm_id, cpu_to_be64(srpt_service_guid)) :
3264 		0;
3265 	if (ret < 0) {
3266 		pr_err("ib_cm_listen() failed: %d (cm_id state = %d)\n", ret,
3267 		       sdev->cm_id->state);
3268 		goto err_cm;
3269 	}
3270 
3271 	INIT_IB_EVENT_HANDLER(&sdev->event_handler, sdev->device,
3272 			      srpt_event_handler);
3273 
3274 	for (i = 1; i <= sdev->device->phys_port_cnt; i++) {
3275 		sport = &sdev->port[i - 1];
3276 		INIT_LIST_HEAD(&sport->nexus_list);
3277 		mutex_init(&sport->mutex);
3278 		sport->sdev = sdev;
3279 		sport->port = i;
3280 		sport->port_attrib.srp_max_rdma_size = DEFAULT_MAX_RDMA_SIZE;
3281 		sport->port_attrib.srp_max_rsp_size = DEFAULT_MAX_RSP_SIZE;
3282 		sport->port_attrib.srp_sq_size = DEF_SRPT_SQ_SIZE;
3283 		sport->port_attrib.use_srq = false;
3284 		INIT_WORK(&sport->work, srpt_refresh_port_work);
3285 
3286 		ret = srpt_refresh_port(sport);
3287 		if (ret) {
3288 			pr_err("MAD registration failed for %s-%d.\n",
3289 			       dev_name(&sdev->device->dev), i);
3290 			i--;
3291 			goto err_port;
3292 		}
3293 	}
3294 
3295 	ib_register_event_handler(&sdev->event_handler);
3296 	spin_lock(&srpt_dev_lock);
3297 	list_add_tail(&sdev->list, &srpt_dev_list);
3298 	spin_unlock(&srpt_dev_lock);
3299 
3300 	ib_set_client_data(device, &srpt_client, sdev);
3301 	pr_debug("added %s.\n", dev_name(&device->dev));
3302 	return 0;
3303 
3304 err_port:
3305 	srpt_unregister_mad_agent(sdev, i);
3306 err_cm:
3307 	if (sdev->cm_id)
3308 		ib_destroy_cm_id(sdev->cm_id);
3309 err_ring:
3310 	srpt_free_srq(sdev);
3311 	ib_dealloc_pd(sdev->pd);
3312 free_dev:
3313 	srpt_sdev_put(sdev);
3314 	pr_info("%s(%s) failed.\n", __func__, dev_name(&device->dev));
3315 	return ret;
3316 }
3317 
3318 /**
3319  * srpt_remove_one - InfiniBand device removal callback function
3320  * @device: Describes a HCA.
3321  * @client_data: The value passed as the third argument to ib_set_client_data().
3322  */
3323 static void srpt_remove_one(struct ib_device *device, void *client_data)
3324 {
3325 	struct srpt_device *sdev = client_data;
3326 	int i;
3327 
3328 	srpt_unregister_mad_agent(sdev, sdev->device->phys_port_cnt);
3329 
3330 	ib_unregister_event_handler(&sdev->event_handler);
3331 
3332 	/* Cancel any work queued by the just unregistered IB event handler. */
3333 	for (i = 0; i < sdev->device->phys_port_cnt; i++)
3334 		cancel_work_sync(&sdev->port[i].work);
3335 
3336 	if (sdev->cm_id)
3337 		ib_destroy_cm_id(sdev->cm_id);
3338 
3339 	ib_set_client_data(device, &srpt_client, NULL);
3340 
3341 	/*
3342 	 * Unregistering a target must happen after destroying sdev->cm_id
3343 	 * such that no new SRP_LOGIN_REQ information units can arrive while
3344 	 * destroying the target.
3345 	 */
3346 	spin_lock(&srpt_dev_lock);
3347 	list_del(&sdev->list);
3348 	spin_unlock(&srpt_dev_lock);
3349 
3350 	for (i = 0; i < sdev->device->phys_port_cnt; i++)
3351 		srpt_release_sport(&sdev->port[i]);
3352 
3353 	srpt_free_srq(sdev);
3354 
3355 	ib_dealloc_pd(sdev->pd);
3356 
3357 	srpt_sdev_put(sdev);
3358 }
3359 
3360 static struct ib_client srpt_client = {
3361 	.name = DRV_NAME,
3362 	.add = srpt_add_one,
3363 	.remove = srpt_remove_one
3364 };
3365 
3366 static int srpt_check_true(struct se_portal_group *se_tpg)
3367 {
3368 	return 1;
3369 }
3370 
3371 static struct srpt_port *srpt_tpg_to_sport(struct se_portal_group *tpg)
3372 {
3373 	return tpg->se_tpg_wwn->priv;
3374 }
3375 
3376 static struct srpt_port_id *srpt_wwn_to_sport_id(struct se_wwn *wwn)
3377 {
3378 	struct srpt_port *sport = wwn->priv;
3379 
3380 	if (sport->guid_id && &sport->guid_id->wwn == wwn)
3381 		return sport->guid_id;
3382 	if (sport->gid_id && &sport->gid_id->wwn == wwn)
3383 		return sport->gid_id;
3384 	WARN_ON_ONCE(true);
3385 	return NULL;
3386 }
3387 
3388 static char *srpt_get_fabric_wwn(struct se_portal_group *tpg)
3389 {
3390 	struct srpt_tpg *stpg = container_of(tpg, typeof(*stpg), tpg);
3391 
3392 	return stpg->sport_id->name;
3393 }
3394 
3395 static u16 srpt_get_tag(struct se_portal_group *tpg)
3396 {
3397 	return 1;
3398 }
3399 
3400 static void srpt_release_cmd(struct se_cmd *se_cmd)
3401 {
3402 	struct srpt_send_ioctx *ioctx = container_of(se_cmd,
3403 				struct srpt_send_ioctx, cmd);
3404 	struct srpt_rdma_ch *ch = ioctx->ch;
3405 	struct srpt_recv_ioctx *recv_ioctx = ioctx->recv_ioctx;
3406 
3407 	WARN_ON_ONCE(ioctx->state != SRPT_STATE_DONE &&
3408 		     !(ioctx->cmd.transport_state & CMD_T_ABORTED));
3409 
3410 	if (recv_ioctx) {
3411 		WARN_ON_ONCE(!list_empty(&recv_ioctx->wait_list));
3412 		ioctx->recv_ioctx = NULL;
3413 		srpt_post_recv(ch->sport->sdev, ch, recv_ioctx);
3414 	}
3415 
3416 	if (ioctx->n_rw_ctx) {
3417 		srpt_free_rw_ctxs(ch, ioctx);
3418 		ioctx->n_rw_ctx = 0;
3419 	}
3420 
3421 	target_free_tag(se_cmd->se_sess, se_cmd);
3422 }
3423 
3424 /**
3425  * srpt_close_session - forcibly close a session
3426  * @se_sess: SCSI target session.
3427  *
3428  * Callback function invoked by the TCM core to clean up sessions associated
3429  * with a node ACL when the user invokes
3430  * rmdir /sys/kernel/config/target/$driver/$port/$tpg/acls/$i_port_id
3431  */
3432 static void srpt_close_session(struct se_session *se_sess)
3433 {
3434 	struct srpt_rdma_ch *ch = se_sess->fabric_sess_ptr;
3435 
3436 	srpt_disconnect_ch_sync(ch);
3437 }
3438 
3439 /* Note: only used from inside debug printk's by the TCM core. */
3440 static int srpt_get_tcm_cmd_state(struct se_cmd *se_cmd)
3441 {
3442 	struct srpt_send_ioctx *ioctx;
3443 
3444 	ioctx = container_of(se_cmd, struct srpt_send_ioctx, cmd);
3445 	return ioctx->state;
3446 }
3447 
3448 static int srpt_parse_guid(u64 *guid, const char *name)
3449 {
3450 	u16 w[4];
3451 	int ret = -EINVAL;
3452 
3453 	if (sscanf(name, "%hx:%hx:%hx:%hx", &w[0], &w[1], &w[2], &w[3]) != 4)
3454 		goto out;
3455 	*guid = get_unaligned_be64(w);
3456 	ret = 0;
3457 out:
3458 	return ret;
3459 }
3460 
3461 /**
3462  * srpt_parse_i_port_id - parse an initiator port ID
3463  * @name: ASCII representation of a 128-bit initiator port ID.
3464  * @i_port_id: Binary 128-bit port ID.
3465  */
3466 static int srpt_parse_i_port_id(u8 i_port_id[16], const char *name)
3467 {
3468 	const char *p;
3469 	unsigned len, count, leading_zero_bytes;
3470 	int ret;
3471 
3472 	p = name;
3473 	if (strncasecmp(p, "0x", 2) == 0)
3474 		p += 2;
3475 	ret = -EINVAL;
3476 	len = strlen(p);
3477 	if (len % 2)
3478 		goto out;
3479 	count = min(len / 2, 16U);
3480 	leading_zero_bytes = 16 - count;
3481 	memset(i_port_id, 0, leading_zero_bytes);
3482 	ret = hex2bin(i_port_id + leading_zero_bytes, p, count);
3483 
3484 out:
3485 	return ret;
3486 }
3487 
3488 /*
3489  * configfs callback function invoked for mkdir
3490  * /sys/kernel/config/target/$driver/$port/$tpg/acls/$i_port_id
3491  *
3492  * i_port_id must be an initiator port GUID, GID or IP address. See also the
3493  * target_alloc_session() calls in this driver. Examples of valid initiator
3494  * port IDs:
3495  * 0x0000000000000000505400fffe4a0b7b
3496  * 0000000000000000505400fffe4a0b7b
3497  * 5054:00ff:fe4a:0b7b
3498  * 192.168.122.76
3499  */
3500 static int srpt_init_nodeacl(struct se_node_acl *se_nacl, const char *name)
3501 {
3502 	struct sockaddr_storage sa;
3503 	u64 guid;
3504 	u8 i_port_id[16];
3505 	int ret;
3506 
3507 	ret = srpt_parse_guid(&guid, name);
3508 	if (ret < 0)
3509 		ret = srpt_parse_i_port_id(i_port_id, name);
3510 	if (ret < 0)
3511 		ret = inet_pton_with_scope(&init_net, AF_UNSPEC, name, NULL,
3512 					   &sa);
3513 	if (ret < 0)
3514 		pr_err("invalid initiator port ID %s\n", name);
3515 	return ret;
3516 }
3517 
3518 static ssize_t srpt_tpg_attrib_srp_max_rdma_size_show(struct config_item *item,
3519 		char *page)
3520 {
3521 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
3522 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
3523 
3524 	return sysfs_emit(page, "%u\n", sport->port_attrib.srp_max_rdma_size);
3525 }
3526 
3527 static ssize_t srpt_tpg_attrib_srp_max_rdma_size_store(struct config_item *item,
3528 		const char *page, size_t count)
3529 {
3530 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
3531 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
3532 	unsigned long val;
3533 	int ret;
3534 
3535 	ret = kstrtoul(page, 0, &val);
3536 	if (ret < 0) {
3537 		pr_err("kstrtoul() failed with ret: %d\n", ret);
3538 		return -EINVAL;
3539 	}
3540 	if (val > MAX_SRPT_RDMA_SIZE) {
3541 		pr_err("val: %lu exceeds MAX_SRPT_RDMA_SIZE: %d\n", val,
3542 			MAX_SRPT_RDMA_SIZE);
3543 		return -EINVAL;
3544 	}
3545 	if (val < DEFAULT_MAX_RDMA_SIZE) {
3546 		pr_err("val: %lu smaller than DEFAULT_MAX_RDMA_SIZE: %d\n",
3547 			val, DEFAULT_MAX_RDMA_SIZE);
3548 		return -EINVAL;
3549 	}
3550 	sport->port_attrib.srp_max_rdma_size = val;
3551 
3552 	return count;
3553 }
3554 
3555 static ssize_t srpt_tpg_attrib_srp_max_rsp_size_show(struct config_item *item,
3556 		char *page)
3557 {
3558 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
3559 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
3560 
3561 	return sysfs_emit(page, "%u\n", sport->port_attrib.srp_max_rsp_size);
3562 }
3563 
3564 static ssize_t srpt_tpg_attrib_srp_max_rsp_size_store(struct config_item *item,
3565 		const char *page, size_t count)
3566 {
3567 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
3568 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
3569 	unsigned long val;
3570 	int ret;
3571 
3572 	ret = kstrtoul(page, 0, &val);
3573 	if (ret < 0) {
3574 		pr_err("kstrtoul() failed with ret: %d\n", ret);
3575 		return -EINVAL;
3576 	}
3577 	if (val > MAX_SRPT_RSP_SIZE) {
3578 		pr_err("val: %lu exceeds MAX_SRPT_RSP_SIZE: %d\n", val,
3579 			MAX_SRPT_RSP_SIZE);
3580 		return -EINVAL;
3581 	}
3582 	if (val < MIN_MAX_RSP_SIZE) {
3583 		pr_err("val: %lu smaller than MIN_MAX_RSP_SIZE: %d\n", val,
3584 			MIN_MAX_RSP_SIZE);
3585 		return -EINVAL;
3586 	}
3587 	sport->port_attrib.srp_max_rsp_size = val;
3588 
3589 	return count;
3590 }
3591 
3592 static ssize_t srpt_tpg_attrib_srp_sq_size_show(struct config_item *item,
3593 		char *page)
3594 {
3595 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
3596 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
3597 
3598 	return sysfs_emit(page, "%u\n", sport->port_attrib.srp_sq_size);
3599 }
3600 
3601 static ssize_t srpt_tpg_attrib_srp_sq_size_store(struct config_item *item,
3602 		const char *page, size_t count)
3603 {
3604 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
3605 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
3606 	unsigned long val;
3607 	int ret;
3608 
3609 	ret = kstrtoul(page, 0, &val);
3610 	if (ret < 0) {
3611 		pr_err("kstrtoul() failed with ret: %d\n", ret);
3612 		return -EINVAL;
3613 	}
3614 	if (val > MAX_SRPT_SRQ_SIZE) {
3615 		pr_err("val: %lu exceeds MAX_SRPT_SRQ_SIZE: %d\n", val,
3616 			MAX_SRPT_SRQ_SIZE);
3617 		return -EINVAL;
3618 	}
3619 	if (val < MIN_SRPT_SRQ_SIZE) {
3620 		pr_err("val: %lu smaller than MIN_SRPT_SRQ_SIZE: %d\n", val,
3621 			MIN_SRPT_SRQ_SIZE);
3622 		return -EINVAL;
3623 	}
3624 	sport->port_attrib.srp_sq_size = val;
3625 
3626 	return count;
3627 }
3628 
3629 static ssize_t srpt_tpg_attrib_use_srq_show(struct config_item *item,
3630 					    char *page)
3631 {
3632 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
3633 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
3634 
3635 	return sysfs_emit(page, "%d\n", sport->port_attrib.use_srq);
3636 }
3637 
3638 static ssize_t srpt_tpg_attrib_use_srq_store(struct config_item *item,
3639 					     const char *page, size_t count)
3640 {
3641 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
3642 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
3643 	struct srpt_device *sdev = sport->sdev;
3644 	unsigned long val;
3645 	bool enabled;
3646 	int ret;
3647 
3648 	ret = kstrtoul(page, 0, &val);
3649 	if (ret < 0)
3650 		return ret;
3651 	if (val != !!val)
3652 		return -EINVAL;
3653 
3654 	ret = mutex_lock_interruptible(&sdev->sdev_mutex);
3655 	if (ret < 0)
3656 		return ret;
3657 	ret = mutex_lock_interruptible(&sport->mutex);
3658 	if (ret < 0)
3659 		goto unlock_sdev;
3660 	enabled = sport->enabled;
3661 	/* Log out all initiator systems before changing 'use_srq'. */
3662 	srpt_set_enabled(sport, false);
3663 	sport->port_attrib.use_srq = val;
3664 	srpt_use_srq(sdev, sport->port_attrib.use_srq);
3665 	srpt_set_enabled(sport, enabled);
3666 	ret = count;
3667 	mutex_unlock(&sport->mutex);
3668 unlock_sdev:
3669 	mutex_unlock(&sdev->sdev_mutex);
3670 
3671 	return ret;
3672 }
3673 
3674 CONFIGFS_ATTR(srpt_tpg_attrib_,  srp_max_rdma_size);
3675 CONFIGFS_ATTR(srpt_tpg_attrib_,  srp_max_rsp_size);
3676 CONFIGFS_ATTR(srpt_tpg_attrib_,  srp_sq_size);
3677 CONFIGFS_ATTR(srpt_tpg_attrib_,  use_srq);
3678 
3679 static struct configfs_attribute *srpt_tpg_attrib_attrs[] = {
3680 	&srpt_tpg_attrib_attr_srp_max_rdma_size,
3681 	&srpt_tpg_attrib_attr_srp_max_rsp_size,
3682 	&srpt_tpg_attrib_attr_srp_sq_size,
3683 	&srpt_tpg_attrib_attr_use_srq,
3684 	NULL,
3685 };
3686 
3687 static struct rdma_cm_id *srpt_create_rdma_id(struct sockaddr *listen_addr)
3688 {
3689 	struct rdma_cm_id *rdma_cm_id;
3690 	int ret;
3691 
3692 	rdma_cm_id = rdma_create_id(&init_net, srpt_rdma_cm_handler,
3693 				    NULL, RDMA_PS_TCP, IB_QPT_RC);
3694 	if (IS_ERR(rdma_cm_id)) {
3695 		pr_err("RDMA/CM ID creation failed: %pe\n", rdma_cm_id);
3696 		goto out;
3697 	}
3698 
3699 	ret = rdma_bind_addr(rdma_cm_id, listen_addr);
3700 	if (ret) {
3701 		char addr_str[64];
3702 
3703 		snprintf(addr_str, sizeof(addr_str), "%pISp", listen_addr);
3704 		pr_err("Binding RDMA/CM ID to address %s failed: %d\n",
3705 		       addr_str, ret);
3706 		rdma_destroy_id(rdma_cm_id);
3707 		rdma_cm_id = ERR_PTR(ret);
3708 		goto out;
3709 	}
3710 
3711 	ret = rdma_listen(rdma_cm_id, 128);
3712 	if (ret) {
3713 		pr_err("rdma_listen() failed: %d\n", ret);
3714 		rdma_destroy_id(rdma_cm_id);
3715 		rdma_cm_id = ERR_PTR(ret);
3716 	}
3717 
3718 out:
3719 	return rdma_cm_id;
3720 }
3721 
3722 static ssize_t srpt_rdma_cm_port_show(struct config_item *item, char *page)
3723 {
3724 	return sysfs_emit(page, "%d\n", rdma_cm_port);
3725 }
3726 
3727 static ssize_t srpt_rdma_cm_port_store(struct config_item *item,
3728 				       const char *page, size_t count)
3729 {
3730 	struct sockaddr_in  addr4 = { .sin_family  = AF_INET  };
3731 	struct sockaddr_in6 addr6 = { .sin6_family = AF_INET6 };
3732 	struct rdma_cm_id *new_id = NULL;
3733 	u16 val;
3734 	int ret;
3735 
3736 	ret = kstrtou16(page, 0, &val);
3737 	if (ret < 0)
3738 		return ret;
3739 	ret = count;
3740 	if (rdma_cm_port == val)
3741 		goto out;
3742 
3743 	if (val) {
3744 		addr6.sin6_port = cpu_to_be16(val);
3745 		new_id = srpt_create_rdma_id((struct sockaddr *)&addr6);
3746 		if (IS_ERR(new_id)) {
3747 			addr4.sin_port = cpu_to_be16(val);
3748 			new_id = srpt_create_rdma_id((struct sockaddr *)&addr4);
3749 			if (IS_ERR(new_id)) {
3750 				ret = PTR_ERR(new_id);
3751 				goto out;
3752 			}
3753 		}
3754 	}
3755 
3756 	mutex_lock(&rdma_cm_mutex);
3757 	rdma_cm_port = val;
3758 	swap(rdma_cm_id, new_id);
3759 	mutex_unlock(&rdma_cm_mutex);
3760 
3761 	if (new_id)
3762 		rdma_destroy_id(new_id);
3763 	ret = count;
3764 out:
3765 	return ret;
3766 }
3767 
3768 CONFIGFS_ATTR(srpt_, rdma_cm_port);
3769 
3770 static struct configfs_attribute *srpt_da_attrs[] = {
3771 	&srpt_attr_rdma_cm_port,
3772 	NULL,
3773 };
3774 
3775 static int srpt_enable_tpg(struct se_portal_group *se_tpg, bool enable)
3776 {
3777 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
3778 
3779 	mutex_lock(&sport->mutex);
3780 	srpt_set_enabled(sport, enable);
3781 	mutex_unlock(&sport->mutex);
3782 
3783 	return 0;
3784 }
3785 
3786 /**
3787  * srpt_make_tpg - configfs callback invoked for mkdir /sys/kernel/config/target/$driver/$port/$tpg
3788  * @wwn: Corresponds to $driver/$port.
3789  * @name: $tpg.
3790  */
3791 static struct se_portal_group *srpt_make_tpg(struct se_wwn *wwn,
3792 					     const char *name)
3793 {
3794 	struct srpt_port_id *sport_id = srpt_wwn_to_sport_id(wwn);
3795 	struct srpt_tpg *stpg;
3796 	int res = -ENOMEM;
3797 
3798 	stpg = kzalloc_obj(*stpg);
3799 	if (!stpg)
3800 		return ERR_PTR(res);
3801 	stpg->sport_id = sport_id;
3802 	res = core_tpg_register(wwn, &stpg->tpg, SCSI_PROTOCOL_SRP);
3803 	if (res) {
3804 		kfree(stpg);
3805 		return ERR_PTR(res);
3806 	}
3807 
3808 	mutex_lock(&sport_id->mutex);
3809 	list_add_tail(&stpg->entry, &sport_id->tpg_list);
3810 	mutex_unlock(&sport_id->mutex);
3811 
3812 	return &stpg->tpg;
3813 }
3814 
3815 /**
3816  * srpt_drop_tpg - configfs callback invoked for rmdir /sys/kernel/config/target/$driver/$port/$tpg
3817  * @tpg: Target portal group to deregister.
3818  */
3819 static void srpt_drop_tpg(struct se_portal_group *tpg)
3820 {
3821 	struct srpt_tpg *stpg = container_of(tpg, typeof(*stpg), tpg);
3822 	struct srpt_port_id *sport_id = stpg->sport_id;
3823 	struct srpt_port *sport = srpt_tpg_to_sport(tpg);
3824 
3825 	mutex_lock(&sport_id->mutex);
3826 	list_del(&stpg->entry);
3827 	mutex_unlock(&sport_id->mutex);
3828 
3829 	sport->enabled = false;
3830 	core_tpg_deregister(tpg);
3831 	kfree(stpg);
3832 }
3833 
3834 /**
3835  * srpt_make_tport - configfs callback invoked for mkdir /sys/kernel/config/target/$driver/$port
3836  * @tf: Not used.
3837  * @group: Not used.
3838  * @name: $port.
3839  */
3840 static struct se_wwn *srpt_make_tport(struct target_fabric_configfs *tf,
3841 				      struct config_group *group,
3842 				      const char *name)
3843 {
3844 	struct port_and_port_id papi = srpt_lookup_port(name);
3845 	struct srpt_port *sport = papi.sport;
3846 	struct srpt_port_id *port_id;
3847 
3848 	if (!papi.port_id)
3849 		return ERR_PTR(-EINVAL);
3850 	if (*papi.port_id) {
3851 		/* Attempt to create a directory that already exists. */
3852 		WARN_ON_ONCE(true);
3853 		return &(*papi.port_id)->wwn;
3854 	}
3855 	port_id = kzalloc_obj(*port_id);
3856 	if (!port_id) {
3857 		srpt_sdev_put(sport->sdev);
3858 		return ERR_PTR(-ENOMEM);
3859 	}
3860 	mutex_init(&port_id->mutex);
3861 	INIT_LIST_HEAD(&port_id->tpg_list);
3862 	port_id->wwn.priv = sport;
3863 	memcpy(port_id->name, port_id == sport->guid_id ? sport->guid_name :
3864 	       sport->gid_name, ARRAY_SIZE(port_id->name));
3865 
3866 	*papi.port_id = port_id;
3867 
3868 	return &port_id->wwn;
3869 }
3870 
3871 /**
3872  * srpt_drop_tport - configfs callback invoked for rmdir /sys/kernel/config/target/$driver/$port
3873  * @wwn: $port.
3874  */
3875 static void srpt_drop_tport(struct se_wwn *wwn)
3876 {
3877 	struct srpt_port_id *port_id = container_of(wwn, typeof(*port_id), wwn);
3878 	struct srpt_port *sport = wwn->priv;
3879 
3880 	if (sport->guid_id == port_id)
3881 		sport->guid_id = NULL;
3882 	else if (sport->gid_id == port_id)
3883 		sport->gid_id = NULL;
3884 	else
3885 		WARN_ON_ONCE(true);
3886 
3887 	srpt_sdev_put(sport->sdev);
3888 	kfree(port_id);
3889 }
3890 
3891 static ssize_t srpt_wwn_version_show(struct config_item *item, char *buf)
3892 {
3893 	return sysfs_emit(buf, "\n");
3894 }
3895 
3896 CONFIGFS_ATTR_RO(srpt_wwn_, version);
3897 
3898 static struct configfs_attribute *srpt_wwn_attrs[] = {
3899 	&srpt_wwn_attr_version,
3900 	NULL,
3901 };
3902 
3903 static const struct target_core_fabric_ops srpt_template = {
3904 	.module				= THIS_MODULE,
3905 	.fabric_name			= "srpt",
3906 	.tpg_get_wwn			= srpt_get_fabric_wwn,
3907 	.tpg_get_tag			= srpt_get_tag,
3908 	.tpg_check_demo_mode_cache	= srpt_check_true,
3909 	.tpg_check_demo_mode_write_protect = srpt_check_true,
3910 	.release_cmd			= srpt_release_cmd,
3911 	.check_stop_free		= srpt_check_stop_free,
3912 	.close_session			= srpt_close_session,
3913 	.sess_get_initiator_sid		= NULL,
3914 	.write_pending			= srpt_write_pending,
3915 	.get_cmd_state			= srpt_get_tcm_cmd_state,
3916 	.queue_data_in			= srpt_queue_data_in,
3917 	.queue_status			= srpt_queue_status,
3918 	.queue_tm_rsp			= srpt_queue_tm_rsp,
3919 	.aborted_task			= srpt_aborted_task,
3920 	/*
3921 	 * Setup function pointers for generic logic in
3922 	 * target_core_fabric_configfs.c
3923 	 */
3924 	.fabric_make_wwn		= srpt_make_tport,
3925 	.fabric_drop_wwn		= srpt_drop_tport,
3926 	.fabric_make_tpg		= srpt_make_tpg,
3927 	.fabric_enable_tpg		= srpt_enable_tpg,
3928 	.fabric_drop_tpg		= srpt_drop_tpg,
3929 	.fabric_init_nodeacl		= srpt_init_nodeacl,
3930 
3931 	.tfc_discovery_attrs		= srpt_da_attrs,
3932 	.tfc_wwn_attrs			= srpt_wwn_attrs,
3933 	.tfc_tpg_attrib_attrs		= srpt_tpg_attrib_attrs,
3934 
3935 	.default_compl_type		= TARGET_QUEUE_COMPL,
3936 	.default_submit_type		= TARGET_DIRECT_SUBMIT,
3937 	.direct_submit_supp		= 1,
3938 };
3939 
3940 /**
3941  * srpt_init_module - kernel module initialization
3942  *
3943  * Note: Since ib_register_client() registers callback functions, and since at
3944  * least one of these callback functions (srpt_add_one()) calls target core
3945  * functions, this driver must be registered with the target core before
3946  * ib_register_client() is called.
3947  */
3948 static int __init srpt_init_module(void)
3949 {
3950 	int ret;
3951 
3952 	ret = -EINVAL;
3953 	if (srp_max_req_size < MIN_MAX_REQ_SIZE) {
3954 		pr_err("invalid value %d for kernel module parameter srp_max_req_size -- must be at least %d.\n",
3955 		       srp_max_req_size, MIN_MAX_REQ_SIZE);
3956 		goto out;
3957 	}
3958 
3959 	if (srpt_srq_size < MIN_SRPT_SRQ_SIZE
3960 	    || srpt_srq_size > MAX_SRPT_SRQ_SIZE) {
3961 		pr_err("invalid value %u for kernel module parameter srpt_srq_size -- must be in the range [%d..%d].\n",
3962 		       srpt_srq_size, MIN_SRPT_SRQ_SIZE, MAX_SRPT_SRQ_SIZE);
3963 		goto out;
3964 	}
3965 
3966 	ret = target_register_template(&srpt_template);
3967 	if (ret)
3968 		goto out;
3969 
3970 	ret = ib_register_client(&srpt_client);
3971 	if (ret) {
3972 		pr_err("couldn't register IB client\n");
3973 		goto out_unregister_target;
3974 	}
3975 
3976 	return 0;
3977 
3978 out_unregister_target:
3979 	target_unregister_template(&srpt_template);
3980 out:
3981 	return ret;
3982 }
3983 
3984 static void __exit srpt_cleanup_module(void)
3985 {
3986 	if (rdma_cm_id)
3987 		rdma_destroy_id(rdma_cm_id);
3988 	ib_unregister_client(&srpt_client);
3989 	target_unregister_template(&srpt_template);
3990 }
3991 
3992 module_init(srpt_init_module);
3993 module_exit(srpt_cleanup_module);
3994