1 /*
2  * Copyright (c) 2006 - 2009 Mellanox Technology Inc.  All rights reserved.
3  * Copyright (C) 2008 - 2011 Bart Van Assche <bvanassche@acm.org>.
4  *
5  * This software is available to you under a choice of one of two
6  * licenses.  You may choose to be licensed under the terms of the GNU
7  * General Public License (GPL) Version 2, available from the file
8  * COPYING in the main directory of this source tree, or the
9  * OpenIB.org BSD license below:
10  *
11  *     Redistribution and use in source and binary forms, with or
12  *     without modification, are permitted provided that the following
13  *     conditions are met:
14  *
15  *      - Redistributions of source code must retain the above
16  *        copyright notice, this list of conditions and the following
17  *        disclaimer.
18  *
19  *      - Redistributions in binary form must reproduce the above
20  *        copyright notice, this list of conditions and the following
21  *        disclaimer in the documentation and/or other materials
22  *        provided with the distribution.
23  *
24  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
25  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
26  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
27  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
28  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
29  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
30  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
31  * SOFTWARE.
32  *
33  */
34 
35 #include <linux/module.h>
36 #include <linux/init.h>
37 #include <linux/slab.h>
38 #include <linux/err.h>
39 #include <linux/ctype.h>
40 #include <linux/kthread.h>
41 #include <linux/string.h>
42 #include <linux/delay.h>
43 #include <linux/atomic.h>
44 #include <scsi/scsi_proto.h>
45 #include <scsi/scsi_tcq.h>
46 #include <target/target_core_base.h>
47 #include <target/target_core_fabric.h>
48 #include "ib_srpt.h"
49 
50 /* Name of this kernel module. */
51 #define DRV_NAME		"ib_srpt"
52 #define DRV_VERSION		"2.0.0"
53 #define DRV_RELDATE		"2011-02-14"
54 
55 #define SRPT_ID_STRING	"Linux SRP target"
56 
57 #undef pr_fmt
58 #define pr_fmt(fmt) DRV_NAME " " fmt
59 
60 MODULE_AUTHOR("Vu Pham and Bart Van Assche");
61 MODULE_DESCRIPTION("InfiniBand SCSI RDMA Protocol target "
62 		   "v" DRV_VERSION " (" DRV_RELDATE ")");
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 
73 static unsigned srp_max_req_size = DEFAULT_MAX_REQ_SIZE;
74 module_param(srp_max_req_size, int, 0444);
75 MODULE_PARM_DESC(srp_max_req_size,
76 		 "Maximum size of SRP request messages in bytes.");
77 
78 static int srpt_srq_size = DEFAULT_SRPT_SRQ_SIZE;
79 module_param(srpt_srq_size, int, 0444);
80 MODULE_PARM_DESC(srpt_srq_size,
81 		 "Shared receive queue (SRQ) size.");
82 
83 static int srpt_get_u64_x(char *buffer, struct kernel_param *kp)
84 {
85 	return sprintf(buffer, "0x%016llx", *(u64 *)kp->arg);
86 }
87 module_param_call(srpt_service_guid, NULL, srpt_get_u64_x, &srpt_service_guid,
88 		  0444);
89 MODULE_PARM_DESC(srpt_service_guid,
90 		 "Using this value for ioc_guid, id_ext, and cm_listen_id"
91 		 " instead of using the node_guid of the first HCA.");
92 
93 static struct ib_client srpt_client;
94 static void srpt_release_cmd(struct se_cmd *se_cmd);
95 static void srpt_free_ch(struct kref *kref);
96 static int srpt_queue_status(struct se_cmd *cmd);
97 static void srpt_recv_done(struct ib_cq *cq, struct ib_wc *wc);
98 static void srpt_send_done(struct ib_cq *cq, struct ib_wc *wc);
99 static void srpt_process_wait_list(struct srpt_rdma_ch *ch);
100 
101 /*
102  * The only allowed channel state changes are those that change the channel
103  * state into a state with a higher numerical value. Hence the new > prev test.
104  */
105 static bool srpt_set_ch_state(struct srpt_rdma_ch *ch, enum rdma_ch_state new)
106 {
107 	unsigned long flags;
108 	enum rdma_ch_state prev;
109 	bool changed = false;
110 
111 	spin_lock_irqsave(&ch->spinlock, flags);
112 	prev = ch->state;
113 	if (new > prev) {
114 		ch->state = new;
115 		changed = true;
116 	}
117 	spin_unlock_irqrestore(&ch->spinlock, flags);
118 
119 	return changed;
120 }
121 
122 /**
123  * srpt_event_handler() - Asynchronous IB event callback function.
124  *
125  * Callback function called by the InfiniBand core when an asynchronous IB
126  * event occurs. This callback may occur in interrupt context. See also
127  * section 11.5.2, Set Asynchronous Event Handler in the InfiniBand
128  * Architecture Specification.
129  */
130 static void srpt_event_handler(struct ib_event_handler *handler,
131 			       struct ib_event *event)
132 {
133 	struct srpt_device *sdev;
134 	struct srpt_port *sport;
135 
136 	sdev = ib_get_client_data(event->device, &srpt_client);
137 	if (!sdev || sdev->device != event->device)
138 		return;
139 
140 	pr_debug("ASYNC event= %d on device= %s\n", event->event,
141 		 sdev->device->name);
142 
143 	switch (event->event) {
144 	case IB_EVENT_PORT_ERR:
145 		if (event->element.port_num <= sdev->device->phys_port_cnt) {
146 			sport = &sdev->port[event->element.port_num - 1];
147 			sport->lid = 0;
148 			sport->sm_lid = 0;
149 		}
150 		break;
151 	case IB_EVENT_PORT_ACTIVE:
152 	case IB_EVENT_LID_CHANGE:
153 	case IB_EVENT_PKEY_CHANGE:
154 	case IB_EVENT_SM_CHANGE:
155 	case IB_EVENT_CLIENT_REREGISTER:
156 	case IB_EVENT_GID_CHANGE:
157 		/* Refresh port data asynchronously. */
158 		if (event->element.port_num <= sdev->device->phys_port_cnt) {
159 			sport = &sdev->port[event->element.port_num - 1];
160 			if (!sport->lid && !sport->sm_lid)
161 				schedule_work(&sport->work);
162 		}
163 		break;
164 	default:
165 		pr_err("received unrecognized IB event %d\n",
166 		       event->event);
167 		break;
168 	}
169 }
170 
171 /**
172  * srpt_srq_event() - SRQ event callback function.
173  */
174 static void srpt_srq_event(struct ib_event *event, void *ctx)
175 {
176 	pr_info("SRQ event %d\n", event->event);
177 }
178 
179 static const char *get_ch_state_name(enum rdma_ch_state s)
180 {
181 	switch (s) {
182 	case CH_CONNECTING:
183 		return "connecting";
184 	case CH_LIVE:
185 		return "live";
186 	case CH_DISCONNECTING:
187 		return "disconnecting";
188 	case CH_DRAINING:
189 		return "draining";
190 	case CH_DISCONNECTED:
191 		return "disconnected";
192 	}
193 	return "???";
194 }
195 
196 /**
197  * srpt_qp_event() - QP event callback function.
198  */
199 static void srpt_qp_event(struct ib_event *event, struct srpt_rdma_ch *ch)
200 {
201 	pr_debug("QP event %d on cm_id=%p sess_name=%s state=%d\n",
202 		 event->event, ch->cm_id, ch->sess_name, ch->state);
203 
204 	switch (event->event) {
205 	case IB_EVENT_COMM_EST:
206 		ib_cm_notify(ch->cm_id, event->event);
207 		break;
208 	case IB_EVENT_QP_LAST_WQE_REACHED:
209 		pr_debug("%s-%d, state %s: received Last WQE event.\n",
210 			 ch->sess_name, ch->qp->qp_num,
211 			 get_ch_state_name(ch->state));
212 		break;
213 	default:
214 		pr_err("received unrecognized IB QP event %d\n", event->event);
215 		break;
216 	}
217 }
218 
219 /**
220  * srpt_set_ioc() - Helper function for initializing an IOUnitInfo structure.
221  *
222  * @slot: one-based slot number.
223  * @value: four-bit value.
224  *
225  * Copies the lowest four bits of value in element slot of the array of four
226  * bit elements called c_list (controller list). The index slot is one-based.
227  */
228 static void srpt_set_ioc(u8 *c_list, u32 slot, u8 value)
229 {
230 	u16 id;
231 	u8 tmp;
232 
233 	id = (slot - 1) / 2;
234 	if (slot & 0x1) {
235 		tmp = c_list[id] & 0xf;
236 		c_list[id] = (value << 4) | tmp;
237 	} else {
238 		tmp = c_list[id] & 0xf0;
239 		c_list[id] = (value & 0xf) | tmp;
240 	}
241 }
242 
243 /**
244  * srpt_get_class_port_info() - Copy ClassPortInfo to a management datagram.
245  *
246  * See also section 16.3.3.1 ClassPortInfo in the InfiniBand Architecture
247  * Specification.
248  */
249 static void srpt_get_class_port_info(struct ib_dm_mad *mad)
250 {
251 	struct ib_class_port_info *cif;
252 
253 	cif = (struct ib_class_port_info *)mad->data;
254 	memset(cif, 0, sizeof(*cif));
255 	cif->base_version = 1;
256 	cif->class_version = 1;
257 
258 	ib_set_cpi_resp_time(cif, 20);
259 	mad->mad_hdr.status = 0;
260 }
261 
262 /**
263  * srpt_get_iou() - Write IOUnitInfo to a management datagram.
264  *
265  * See also section 16.3.3.3 IOUnitInfo in the InfiniBand Architecture
266  * Specification. See also section B.7, table B.6 in the SRP r16a document.
267  */
268 static void srpt_get_iou(struct ib_dm_mad *mad)
269 {
270 	struct ib_dm_iou_info *ioui;
271 	u8 slot;
272 	int i;
273 
274 	ioui = (struct ib_dm_iou_info *)mad->data;
275 	ioui->change_id = cpu_to_be16(1);
276 	ioui->max_controllers = 16;
277 
278 	/* set present for slot 1 and empty for the rest */
279 	srpt_set_ioc(ioui->controller_list, 1, 1);
280 	for (i = 1, slot = 2; i < 16; i++, slot++)
281 		srpt_set_ioc(ioui->controller_list, slot, 0);
282 
283 	mad->mad_hdr.status = 0;
284 }
285 
286 /**
287  * srpt_get_ioc() - Write IOControllerprofile to a management datagram.
288  *
289  * See also section 16.3.3.4 IOControllerProfile in the InfiniBand
290  * Architecture Specification. See also section B.7, table B.7 in the SRP
291  * r16a document.
292  */
293 static void srpt_get_ioc(struct srpt_port *sport, u32 slot,
294 			 struct ib_dm_mad *mad)
295 {
296 	struct srpt_device *sdev = sport->sdev;
297 	struct ib_dm_ioc_profile *iocp;
298 
299 	iocp = (struct ib_dm_ioc_profile *)mad->data;
300 
301 	if (!slot || slot > 16) {
302 		mad->mad_hdr.status
303 			= cpu_to_be16(DM_MAD_STATUS_INVALID_FIELD);
304 		return;
305 	}
306 
307 	if (slot > 2) {
308 		mad->mad_hdr.status
309 			= cpu_to_be16(DM_MAD_STATUS_NO_IOC);
310 		return;
311 	}
312 
313 	memset(iocp, 0, sizeof(*iocp));
314 	strcpy(iocp->id_string, SRPT_ID_STRING);
315 	iocp->guid = cpu_to_be64(srpt_service_guid);
316 	iocp->vendor_id = cpu_to_be32(sdev->device->attrs.vendor_id);
317 	iocp->device_id = cpu_to_be32(sdev->device->attrs.vendor_part_id);
318 	iocp->device_version = cpu_to_be16(sdev->device->attrs.hw_ver);
319 	iocp->subsys_vendor_id = cpu_to_be32(sdev->device->attrs.vendor_id);
320 	iocp->subsys_device_id = 0x0;
321 	iocp->io_class = cpu_to_be16(SRP_REV16A_IB_IO_CLASS);
322 	iocp->io_subclass = cpu_to_be16(SRP_IO_SUBCLASS);
323 	iocp->protocol = cpu_to_be16(SRP_PROTOCOL);
324 	iocp->protocol_version = cpu_to_be16(SRP_PROTOCOL_VERSION);
325 	iocp->send_queue_depth = cpu_to_be16(sdev->srq_size);
326 	iocp->rdma_read_depth = 4;
327 	iocp->send_size = cpu_to_be32(srp_max_req_size);
328 	iocp->rdma_size = cpu_to_be32(min(sport->port_attrib.srp_max_rdma_size,
329 					  1U << 24));
330 	iocp->num_svc_entries = 1;
331 	iocp->op_cap_mask = SRP_SEND_TO_IOC | SRP_SEND_FROM_IOC |
332 		SRP_RDMA_READ_FROM_IOC | SRP_RDMA_WRITE_FROM_IOC;
333 
334 	mad->mad_hdr.status = 0;
335 }
336 
337 /**
338  * srpt_get_svc_entries() - Write ServiceEntries to a management datagram.
339  *
340  * See also section 16.3.3.5 ServiceEntries in the InfiniBand Architecture
341  * Specification. See also section B.7, table B.8 in the SRP r16a document.
342  */
343 static void srpt_get_svc_entries(u64 ioc_guid,
344 				 u16 slot, u8 hi, u8 lo, struct ib_dm_mad *mad)
345 {
346 	struct ib_dm_svc_entries *svc_entries;
347 
348 	WARN_ON(!ioc_guid);
349 
350 	if (!slot || slot > 16) {
351 		mad->mad_hdr.status
352 			= cpu_to_be16(DM_MAD_STATUS_INVALID_FIELD);
353 		return;
354 	}
355 
356 	if (slot > 2 || lo > hi || hi > 1) {
357 		mad->mad_hdr.status
358 			= cpu_to_be16(DM_MAD_STATUS_NO_IOC);
359 		return;
360 	}
361 
362 	svc_entries = (struct ib_dm_svc_entries *)mad->data;
363 	memset(svc_entries, 0, sizeof(*svc_entries));
364 	svc_entries->service_entries[0].id = cpu_to_be64(ioc_guid);
365 	snprintf(svc_entries->service_entries[0].name,
366 		 sizeof(svc_entries->service_entries[0].name),
367 		 "%s%016llx",
368 		 SRP_SERVICE_NAME_PREFIX,
369 		 ioc_guid);
370 
371 	mad->mad_hdr.status = 0;
372 }
373 
374 /**
375  * srpt_mgmt_method_get() - Process a received management datagram.
376  * @sp:      source port through which the MAD has been received.
377  * @rq_mad:  received MAD.
378  * @rsp_mad: response MAD.
379  */
380 static void srpt_mgmt_method_get(struct srpt_port *sp, struct ib_mad *rq_mad,
381 				 struct ib_dm_mad *rsp_mad)
382 {
383 	u16 attr_id;
384 	u32 slot;
385 	u8 hi, lo;
386 
387 	attr_id = be16_to_cpu(rq_mad->mad_hdr.attr_id);
388 	switch (attr_id) {
389 	case DM_ATTR_CLASS_PORT_INFO:
390 		srpt_get_class_port_info(rsp_mad);
391 		break;
392 	case DM_ATTR_IOU_INFO:
393 		srpt_get_iou(rsp_mad);
394 		break;
395 	case DM_ATTR_IOC_PROFILE:
396 		slot = be32_to_cpu(rq_mad->mad_hdr.attr_mod);
397 		srpt_get_ioc(sp, slot, rsp_mad);
398 		break;
399 	case DM_ATTR_SVC_ENTRIES:
400 		slot = be32_to_cpu(rq_mad->mad_hdr.attr_mod);
401 		hi = (u8) ((slot >> 8) & 0xff);
402 		lo = (u8) (slot & 0xff);
403 		slot = (u16) ((slot >> 16) & 0xffff);
404 		srpt_get_svc_entries(srpt_service_guid,
405 				     slot, hi, lo, rsp_mad);
406 		break;
407 	default:
408 		rsp_mad->mad_hdr.status =
409 		    cpu_to_be16(DM_MAD_STATUS_UNSUP_METHOD_ATTR);
410 		break;
411 	}
412 }
413 
414 /**
415  * srpt_mad_send_handler() - Post MAD-send callback function.
416  */
417 static void srpt_mad_send_handler(struct ib_mad_agent *mad_agent,
418 				  struct ib_mad_send_wc *mad_wc)
419 {
420 	ib_destroy_ah(mad_wc->send_buf->ah);
421 	ib_free_send_mad(mad_wc->send_buf);
422 }
423 
424 /**
425  * srpt_mad_recv_handler() - MAD reception callback function.
426  */
427 static void srpt_mad_recv_handler(struct ib_mad_agent *mad_agent,
428 				  struct ib_mad_send_buf *send_buf,
429 				  struct ib_mad_recv_wc *mad_wc)
430 {
431 	struct srpt_port *sport = (struct srpt_port *)mad_agent->context;
432 	struct ib_ah *ah;
433 	struct ib_mad_send_buf *rsp;
434 	struct ib_dm_mad *dm_mad;
435 
436 	if (!mad_wc || !mad_wc->recv_buf.mad)
437 		return;
438 
439 	ah = ib_create_ah_from_wc(mad_agent->qp->pd, mad_wc->wc,
440 				  mad_wc->recv_buf.grh, mad_agent->port_num);
441 	if (IS_ERR(ah))
442 		goto err;
443 
444 	BUILD_BUG_ON(offsetof(struct ib_dm_mad, data) != IB_MGMT_DEVICE_HDR);
445 
446 	rsp = ib_create_send_mad(mad_agent, mad_wc->wc->src_qp,
447 				 mad_wc->wc->pkey_index, 0,
448 				 IB_MGMT_DEVICE_HDR, IB_MGMT_DEVICE_DATA,
449 				 GFP_KERNEL,
450 				 IB_MGMT_BASE_VERSION);
451 	if (IS_ERR(rsp))
452 		goto err_rsp;
453 
454 	rsp->ah = ah;
455 
456 	dm_mad = rsp->mad;
457 	memcpy(dm_mad, mad_wc->recv_buf.mad, sizeof(*dm_mad));
458 	dm_mad->mad_hdr.method = IB_MGMT_METHOD_GET_RESP;
459 	dm_mad->mad_hdr.status = 0;
460 
461 	switch (mad_wc->recv_buf.mad->mad_hdr.method) {
462 	case IB_MGMT_METHOD_GET:
463 		srpt_mgmt_method_get(sport, mad_wc->recv_buf.mad, dm_mad);
464 		break;
465 	case IB_MGMT_METHOD_SET:
466 		dm_mad->mad_hdr.status =
467 		    cpu_to_be16(DM_MAD_STATUS_UNSUP_METHOD_ATTR);
468 		break;
469 	default:
470 		dm_mad->mad_hdr.status =
471 		    cpu_to_be16(DM_MAD_STATUS_UNSUP_METHOD);
472 		break;
473 	}
474 
475 	if (!ib_post_send_mad(rsp, NULL)) {
476 		ib_free_recv_mad(mad_wc);
477 		/* will destroy_ah & free_send_mad in send completion */
478 		return;
479 	}
480 
481 	ib_free_send_mad(rsp);
482 
483 err_rsp:
484 	ib_destroy_ah(ah);
485 err:
486 	ib_free_recv_mad(mad_wc);
487 }
488 
489 /**
490  * srpt_refresh_port() - Configure a HCA port.
491  *
492  * Enable InfiniBand management datagram processing, update the cached sm_lid,
493  * lid and gid values, and register a callback function for processing MADs
494  * on the specified port.
495  *
496  * Note: It is safe to call this function more than once for the same port.
497  */
498 static int srpt_refresh_port(struct srpt_port *sport)
499 {
500 	struct ib_mad_reg_req reg_req;
501 	struct ib_port_modify port_modify;
502 	struct ib_port_attr port_attr;
503 	int ret;
504 
505 	memset(&port_modify, 0, sizeof(port_modify));
506 	port_modify.set_port_cap_mask = IB_PORT_DEVICE_MGMT_SUP;
507 	port_modify.clr_port_cap_mask = 0;
508 
509 	ret = ib_modify_port(sport->sdev->device, sport->port, 0, &port_modify);
510 	if (ret)
511 		goto err_mod_port;
512 
513 	ret = ib_query_port(sport->sdev->device, sport->port, &port_attr);
514 	if (ret)
515 		goto err_query_port;
516 
517 	sport->sm_lid = port_attr.sm_lid;
518 	sport->lid = port_attr.lid;
519 
520 	ret = ib_query_gid(sport->sdev->device, sport->port, 0, &sport->gid,
521 			   NULL);
522 	if (ret)
523 		goto err_query_port;
524 
525 	snprintf(sport->port_guid, sizeof(sport->port_guid),
526 		"0x%016llx%016llx",
527 		be64_to_cpu(sport->gid.global.subnet_prefix),
528 		be64_to_cpu(sport->gid.global.interface_id));
529 
530 	if (!sport->mad_agent) {
531 		memset(&reg_req, 0, sizeof(reg_req));
532 		reg_req.mgmt_class = IB_MGMT_CLASS_DEVICE_MGMT;
533 		reg_req.mgmt_class_version = IB_MGMT_BASE_VERSION;
534 		set_bit(IB_MGMT_METHOD_GET, reg_req.method_mask);
535 		set_bit(IB_MGMT_METHOD_SET, reg_req.method_mask);
536 
537 		sport->mad_agent = ib_register_mad_agent(sport->sdev->device,
538 							 sport->port,
539 							 IB_QPT_GSI,
540 							 &reg_req, 0,
541 							 srpt_mad_send_handler,
542 							 srpt_mad_recv_handler,
543 							 sport, 0);
544 		if (IS_ERR(sport->mad_agent)) {
545 			ret = PTR_ERR(sport->mad_agent);
546 			sport->mad_agent = NULL;
547 			goto err_query_port;
548 		}
549 	}
550 
551 	return 0;
552 
553 err_query_port:
554 
555 	port_modify.set_port_cap_mask = 0;
556 	port_modify.clr_port_cap_mask = IB_PORT_DEVICE_MGMT_SUP;
557 	ib_modify_port(sport->sdev->device, sport->port, 0, &port_modify);
558 
559 err_mod_port:
560 
561 	return ret;
562 }
563 
564 /**
565  * srpt_unregister_mad_agent() - Unregister MAD callback functions.
566  *
567  * Note: It is safe to call this function more than once for the same device.
568  */
569 static void srpt_unregister_mad_agent(struct srpt_device *sdev)
570 {
571 	struct ib_port_modify port_modify = {
572 		.clr_port_cap_mask = IB_PORT_DEVICE_MGMT_SUP,
573 	};
574 	struct srpt_port *sport;
575 	int i;
576 
577 	for (i = 1; i <= sdev->device->phys_port_cnt; i++) {
578 		sport = &sdev->port[i - 1];
579 		WARN_ON(sport->port != i);
580 		if (ib_modify_port(sdev->device, i, 0, &port_modify) < 0)
581 			pr_err("disabling MAD processing failed.\n");
582 		if (sport->mad_agent) {
583 			ib_unregister_mad_agent(sport->mad_agent);
584 			sport->mad_agent = NULL;
585 		}
586 	}
587 }
588 
589 /**
590  * srpt_alloc_ioctx() - Allocate an SRPT I/O context structure.
591  */
592 static struct srpt_ioctx *srpt_alloc_ioctx(struct srpt_device *sdev,
593 					   int ioctx_size, int dma_size,
594 					   enum dma_data_direction dir)
595 {
596 	struct srpt_ioctx *ioctx;
597 
598 	ioctx = kmalloc(ioctx_size, GFP_KERNEL);
599 	if (!ioctx)
600 		goto err;
601 
602 	ioctx->buf = kmalloc(dma_size, GFP_KERNEL);
603 	if (!ioctx->buf)
604 		goto err_free_ioctx;
605 
606 	ioctx->dma = ib_dma_map_single(sdev->device, ioctx->buf, dma_size, dir);
607 	if (ib_dma_mapping_error(sdev->device, ioctx->dma))
608 		goto err_free_buf;
609 
610 	return ioctx;
611 
612 err_free_buf:
613 	kfree(ioctx->buf);
614 err_free_ioctx:
615 	kfree(ioctx);
616 err:
617 	return NULL;
618 }
619 
620 /**
621  * srpt_free_ioctx() - Free an SRPT I/O context structure.
622  */
623 static void srpt_free_ioctx(struct srpt_device *sdev, struct srpt_ioctx *ioctx,
624 			    int dma_size, enum dma_data_direction dir)
625 {
626 	if (!ioctx)
627 		return;
628 
629 	ib_dma_unmap_single(sdev->device, ioctx->dma, dma_size, dir);
630 	kfree(ioctx->buf);
631 	kfree(ioctx);
632 }
633 
634 /**
635  * srpt_alloc_ioctx_ring() - Allocate a ring of SRPT I/O context structures.
636  * @sdev:       Device to allocate the I/O context ring for.
637  * @ring_size:  Number of elements in the I/O context ring.
638  * @ioctx_size: I/O context size.
639  * @dma_size:   DMA buffer size.
640  * @dir:        DMA data direction.
641  */
642 static struct srpt_ioctx **srpt_alloc_ioctx_ring(struct srpt_device *sdev,
643 				int ring_size, int ioctx_size,
644 				int dma_size, enum dma_data_direction dir)
645 {
646 	struct srpt_ioctx **ring;
647 	int i;
648 
649 	WARN_ON(ioctx_size != sizeof(struct srpt_recv_ioctx)
650 		&& ioctx_size != sizeof(struct srpt_send_ioctx));
651 
652 	ring = kmalloc(ring_size * sizeof(ring[0]), GFP_KERNEL);
653 	if (!ring)
654 		goto out;
655 	for (i = 0; i < ring_size; ++i) {
656 		ring[i] = srpt_alloc_ioctx(sdev, ioctx_size, dma_size, dir);
657 		if (!ring[i])
658 			goto err;
659 		ring[i]->index = i;
660 	}
661 	goto out;
662 
663 err:
664 	while (--i >= 0)
665 		srpt_free_ioctx(sdev, ring[i], dma_size, dir);
666 	kfree(ring);
667 	ring = NULL;
668 out:
669 	return ring;
670 }
671 
672 /**
673  * srpt_free_ioctx_ring() - Free the ring of SRPT I/O context structures.
674  */
675 static void srpt_free_ioctx_ring(struct srpt_ioctx **ioctx_ring,
676 				 struct srpt_device *sdev, int ring_size,
677 				 int dma_size, enum dma_data_direction dir)
678 {
679 	int i;
680 
681 	for (i = 0; i < ring_size; ++i)
682 		srpt_free_ioctx(sdev, ioctx_ring[i], dma_size, dir);
683 	kfree(ioctx_ring);
684 }
685 
686 /**
687  * srpt_get_cmd_state() - Get the state of a SCSI command.
688  */
689 static enum srpt_command_state srpt_get_cmd_state(struct srpt_send_ioctx *ioctx)
690 {
691 	enum srpt_command_state state;
692 	unsigned long flags;
693 
694 	BUG_ON(!ioctx);
695 
696 	spin_lock_irqsave(&ioctx->spinlock, flags);
697 	state = ioctx->state;
698 	spin_unlock_irqrestore(&ioctx->spinlock, flags);
699 	return state;
700 }
701 
702 /**
703  * srpt_set_cmd_state() - Set the state of a SCSI command.
704  *
705  * Does not modify the state of aborted commands. Returns the previous command
706  * state.
707  */
708 static enum srpt_command_state srpt_set_cmd_state(struct srpt_send_ioctx *ioctx,
709 						  enum srpt_command_state new)
710 {
711 	enum srpt_command_state previous;
712 	unsigned long flags;
713 
714 	BUG_ON(!ioctx);
715 
716 	spin_lock_irqsave(&ioctx->spinlock, flags);
717 	previous = ioctx->state;
718 	if (previous != SRPT_STATE_DONE)
719 		ioctx->state = new;
720 	spin_unlock_irqrestore(&ioctx->spinlock, flags);
721 
722 	return previous;
723 }
724 
725 /**
726  * srpt_test_and_set_cmd_state() - Test and set the state of a command.
727  *
728  * Returns true if and only if the previous command state was equal to 'old'.
729  */
730 static bool srpt_test_and_set_cmd_state(struct srpt_send_ioctx *ioctx,
731 					enum srpt_command_state old,
732 					enum srpt_command_state new)
733 {
734 	enum srpt_command_state previous;
735 	unsigned long flags;
736 
737 	WARN_ON(!ioctx);
738 	WARN_ON(old == SRPT_STATE_DONE);
739 	WARN_ON(new == SRPT_STATE_NEW);
740 
741 	spin_lock_irqsave(&ioctx->spinlock, flags);
742 	previous = ioctx->state;
743 	if (previous == old)
744 		ioctx->state = new;
745 	spin_unlock_irqrestore(&ioctx->spinlock, flags);
746 	return previous == old;
747 }
748 
749 /**
750  * srpt_post_recv() - Post an IB receive request.
751  */
752 static int srpt_post_recv(struct srpt_device *sdev,
753 			  struct srpt_recv_ioctx *ioctx)
754 {
755 	struct ib_sge list;
756 	struct ib_recv_wr wr, *bad_wr;
757 
758 	BUG_ON(!sdev);
759 	list.addr = ioctx->ioctx.dma;
760 	list.length = srp_max_req_size;
761 	list.lkey = sdev->pd->local_dma_lkey;
762 
763 	ioctx->ioctx.cqe.done = srpt_recv_done;
764 	wr.wr_cqe = &ioctx->ioctx.cqe;
765 	wr.next = NULL;
766 	wr.sg_list = &list;
767 	wr.num_sge = 1;
768 
769 	return ib_post_srq_recv(sdev->srq, &wr, &bad_wr);
770 }
771 
772 /**
773  * srpt_zerolength_write() - Perform a zero-length RDMA write.
774  *
775  * A quote from the InfiniBand specification: C9-88: For an HCA responder
776  * using Reliable Connection service, for each zero-length RDMA READ or WRITE
777  * request, the R_Key shall not be validated, even if the request includes
778  * Immediate data.
779  */
780 static int srpt_zerolength_write(struct srpt_rdma_ch *ch)
781 {
782 	struct ib_send_wr wr, *bad_wr;
783 
784 	memset(&wr, 0, sizeof(wr));
785 	wr.opcode = IB_WR_RDMA_WRITE;
786 	wr.wr_cqe = &ch->zw_cqe;
787 	wr.send_flags = IB_SEND_SIGNALED;
788 	return ib_post_send(ch->qp, &wr, &bad_wr);
789 }
790 
791 static void srpt_zerolength_write_done(struct ib_cq *cq, struct ib_wc *wc)
792 {
793 	struct srpt_rdma_ch *ch = cq->cq_context;
794 
795 	if (wc->status == IB_WC_SUCCESS) {
796 		srpt_process_wait_list(ch);
797 	} else {
798 		if (srpt_set_ch_state(ch, CH_DISCONNECTED))
799 			schedule_work(&ch->release_work);
800 		else
801 			WARN_ONCE(1, "%s-%d\n", ch->sess_name, ch->qp->qp_num);
802 	}
803 }
804 
805 static int srpt_alloc_rw_ctxs(struct srpt_send_ioctx *ioctx,
806 		struct srp_direct_buf *db, int nbufs, struct scatterlist **sg,
807 		unsigned *sg_cnt)
808 {
809 	enum dma_data_direction dir = target_reverse_dma_direction(&ioctx->cmd);
810 	struct srpt_rdma_ch *ch = ioctx->ch;
811 	struct scatterlist *prev = NULL;
812 	unsigned prev_nents;
813 	int ret, i;
814 
815 	if (nbufs == 1) {
816 		ioctx->rw_ctxs = &ioctx->s_rw_ctx;
817 	} else {
818 		ioctx->rw_ctxs = kmalloc_array(nbufs, sizeof(*ioctx->rw_ctxs),
819 			GFP_KERNEL);
820 		if (!ioctx->rw_ctxs)
821 			return -ENOMEM;
822 	}
823 
824 	for (i = ioctx->n_rw_ctx; i < nbufs; i++, db++) {
825 		struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
826 		u64 remote_addr = be64_to_cpu(db->va);
827 		u32 size = be32_to_cpu(db->len);
828 		u32 rkey = be32_to_cpu(db->key);
829 
830 		ret = target_alloc_sgl(&ctx->sg, &ctx->nents, size, false,
831 				i < nbufs - 1);
832 		if (ret)
833 			goto unwind;
834 
835 		ret = rdma_rw_ctx_init(&ctx->rw, ch->qp, ch->sport->port,
836 				ctx->sg, ctx->nents, 0, remote_addr, rkey, dir);
837 		if (ret < 0) {
838 			target_free_sgl(ctx->sg, ctx->nents);
839 			goto unwind;
840 		}
841 
842 		ioctx->n_rdma += ret;
843 		ioctx->n_rw_ctx++;
844 
845 		if (prev) {
846 			sg_unmark_end(&prev[prev_nents - 1]);
847 			sg_chain(prev, prev_nents + 1, ctx->sg);
848 		} else {
849 			*sg = ctx->sg;
850 		}
851 
852 		prev = ctx->sg;
853 		prev_nents = ctx->nents;
854 
855 		*sg_cnt += ctx->nents;
856 	}
857 
858 	return 0;
859 
860 unwind:
861 	while (--i >= 0) {
862 		struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
863 
864 		rdma_rw_ctx_destroy(&ctx->rw, ch->qp, ch->sport->port,
865 				ctx->sg, ctx->nents, dir);
866 		target_free_sgl(ctx->sg, ctx->nents);
867 	}
868 	if (ioctx->rw_ctxs != &ioctx->s_rw_ctx)
869 		kfree(ioctx->rw_ctxs);
870 	return ret;
871 }
872 
873 static void srpt_free_rw_ctxs(struct srpt_rdma_ch *ch,
874 				    struct srpt_send_ioctx *ioctx)
875 {
876 	enum dma_data_direction dir = target_reverse_dma_direction(&ioctx->cmd);
877 	int i;
878 
879 	for (i = 0; i < ioctx->n_rw_ctx; i++) {
880 		struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
881 
882 		rdma_rw_ctx_destroy(&ctx->rw, ch->qp, ch->sport->port,
883 				ctx->sg, ctx->nents, dir);
884 		target_free_sgl(ctx->sg, ctx->nents);
885 	}
886 
887 	if (ioctx->rw_ctxs != &ioctx->s_rw_ctx)
888 		kfree(ioctx->rw_ctxs);
889 }
890 
891 static inline void *srpt_get_desc_buf(struct srp_cmd *srp_cmd)
892 {
893 	/*
894 	 * The pointer computations below will only be compiled correctly
895 	 * if srp_cmd::add_data is declared as s8*, u8*, s8[] or u8[], so check
896 	 * whether srp_cmd::add_data has been declared as a byte pointer.
897 	 */
898 	BUILD_BUG_ON(!__same_type(srp_cmd->add_data[0], (s8)0) &&
899 		     !__same_type(srp_cmd->add_data[0], (u8)0));
900 
901 	/*
902 	 * According to the SRP spec, the lower two bits of the 'ADDITIONAL
903 	 * CDB LENGTH' field are reserved and the size in bytes of this field
904 	 * is four times the value specified in bits 3..7. Hence the "& ~3".
905 	 */
906 	return srp_cmd->add_data + (srp_cmd->add_cdb_len & ~3);
907 }
908 
909 /**
910  * srpt_get_desc_tbl() - Parse the data descriptors of an SRP_CMD request.
911  * @ioctx: Pointer to the I/O context associated with the request.
912  * @srp_cmd: Pointer to the SRP_CMD request data.
913  * @dir: Pointer to the variable to which the transfer direction will be
914  *   written.
915  * @data_len: Pointer to the variable to which the total data length of all
916  *   descriptors in the SRP_CMD request will be written.
917  *
918  * This function initializes ioctx->nrbuf and ioctx->r_bufs.
919  *
920  * Returns -EINVAL when the SRP_CMD request contains inconsistent descriptors;
921  * -ENOMEM when memory allocation fails and zero upon success.
922  */
923 static int srpt_get_desc_tbl(struct srpt_send_ioctx *ioctx,
924 		struct srp_cmd *srp_cmd, enum dma_data_direction *dir,
925 		struct scatterlist **sg, unsigned *sg_cnt, u64 *data_len)
926 {
927 	BUG_ON(!dir);
928 	BUG_ON(!data_len);
929 
930 	/*
931 	 * The lower four bits of the buffer format field contain the DATA-IN
932 	 * buffer descriptor format, and the highest four bits contain the
933 	 * DATA-OUT buffer descriptor format.
934 	 */
935 	if (srp_cmd->buf_fmt & 0xf)
936 		/* DATA-IN: transfer data from target to initiator (read). */
937 		*dir = DMA_FROM_DEVICE;
938 	else if (srp_cmd->buf_fmt >> 4)
939 		/* DATA-OUT: transfer data from initiator to target (write). */
940 		*dir = DMA_TO_DEVICE;
941 	else
942 		*dir = DMA_NONE;
943 
944 	/* initialize data_direction early as srpt_alloc_rw_ctxs needs it */
945 	ioctx->cmd.data_direction = *dir;
946 
947 	if (((srp_cmd->buf_fmt & 0xf) == SRP_DATA_DESC_DIRECT) ||
948 	    ((srp_cmd->buf_fmt >> 4) == SRP_DATA_DESC_DIRECT)) {
949 	    	struct srp_direct_buf *db = srpt_get_desc_buf(srp_cmd);
950 
951 		*data_len = be32_to_cpu(db->len);
952 		return srpt_alloc_rw_ctxs(ioctx, db, 1, sg, sg_cnt);
953 	} else if (((srp_cmd->buf_fmt & 0xf) == SRP_DATA_DESC_INDIRECT) ||
954 		   ((srp_cmd->buf_fmt >> 4) == SRP_DATA_DESC_INDIRECT)) {
955 		struct srp_indirect_buf *idb = srpt_get_desc_buf(srp_cmd);
956 		int nbufs = be32_to_cpu(idb->table_desc.len) /
957 				sizeof(struct srp_direct_buf);
958 
959 		if (nbufs >
960 		    (srp_cmd->data_out_desc_cnt + srp_cmd->data_in_desc_cnt)) {
961 			pr_err("received unsupported SRP_CMD request"
962 			       " type (%u out + %u in != %u / %zu)\n",
963 			       srp_cmd->data_out_desc_cnt,
964 			       srp_cmd->data_in_desc_cnt,
965 			       be32_to_cpu(idb->table_desc.len),
966 			       sizeof(struct srp_direct_buf));
967 			return -EINVAL;
968 		}
969 
970 		*data_len = be32_to_cpu(idb->len);
971 		return srpt_alloc_rw_ctxs(ioctx, idb->desc_list, nbufs,
972 				sg, sg_cnt);
973 	} else {
974 		*data_len = 0;
975 		return 0;
976 	}
977 }
978 
979 /**
980  * srpt_init_ch_qp() - Initialize queue pair attributes.
981  *
982  * Initialized the attributes of queue pair 'qp' by allowing local write,
983  * remote read and remote write. Also transitions 'qp' to state IB_QPS_INIT.
984  */
985 static int srpt_init_ch_qp(struct srpt_rdma_ch *ch, struct ib_qp *qp)
986 {
987 	struct ib_qp_attr *attr;
988 	int ret;
989 
990 	attr = kzalloc(sizeof(*attr), GFP_KERNEL);
991 	if (!attr)
992 		return -ENOMEM;
993 
994 	attr->qp_state = IB_QPS_INIT;
995 	attr->qp_access_flags = IB_ACCESS_LOCAL_WRITE | IB_ACCESS_REMOTE_READ |
996 	    IB_ACCESS_REMOTE_WRITE;
997 	attr->port_num = ch->sport->port;
998 	attr->pkey_index = 0;
999 
1000 	ret = ib_modify_qp(qp, attr,
1001 			   IB_QP_STATE | IB_QP_ACCESS_FLAGS | IB_QP_PORT |
1002 			   IB_QP_PKEY_INDEX);
1003 
1004 	kfree(attr);
1005 	return ret;
1006 }
1007 
1008 /**
1009  * srpt_ch_qp_rtr() - Change the state of a channel to 'ready to receive' (RTR).
1010  * @ch: channel of the queue pair.
1011  * @qp: queue pair to change the state of.
1012  *
1013  * Returns zero upon success and a negative value upon failure.
1014  *
1015  * Note: currently a struct ib_qp_attr takes 136 bytes on a 64-bit system.
1016  * If this structure ever becomes larger, it might be necessary to allocate
1017  * it dynamically instead of on the stack.
1018  */
1019 static int srpt_ch_qp_rtr(struct srpt_rdma_ch *ch, struct ib_qp *qp)
1020 {
1021 	struct ib_qp_attr qp_attr;
1022 	int attr_mask;
1023 	int ret;
1024 
1025 	qp_attr.qp_state = IB_QPS_RTR;
1026 	ret = ib_cm_init_qp_attr(ch->cm_id, &qp_attr, &attr_mask);
1027 	if (ret)
1028 		goto out;
1029 
1030 	qp_attr.max_dest_rd_atomic = 4;
1031 
1032 	ret = ib_modify_qp(qp, &qp_attr, attr_mask);
1033 
1034 out:
1035 	return ret;
1036 }
1037 
1038 /**
1039  * srpt_ch_qp_rts() - Change the state of a channel to 'ready to send' (RTS).
1040  * @ch: channel of the queue pair.
1041  * @qp: queue pair to change the state of.
1042  *
1043  * Returns zero upon success and a negative value upon failure.
1044  *
1045  * Note: currently a struct ib_qp_attr takes 136 bytes on a 64-bit system.
1046  * If this structure ever becomes larger, it might be necessary to allocate
1047  * it dynamically instead of on the stack.
1048  */
1049 static int srpt_ch_qp_rts(struct srpt_rdma_ch *ch, struct ib_qp *qp)
1050 {
1051 	struct ib_qp_attr qp_attr;
1052 	int attr_mask;
1053 	int ret;
1054 
1055 	qp_attr.qp_state = IB_QPS_RTS;
1056 	ret = ib_cm_init_qp_attr(ch->cm_id, &qp_attr, &attr_mask);
1057 	if (ret)
1058 		goto out;
1059 
1060 	qp_attr.max_rd_atomic = 4;
1061 
1062 	ret = ib_modify_qp(qp, &qp_attr, attr_mask);
1063 
1064 out:
1065 	return ret;
1066 }
1067 
1068 /**
1069  * srpt_ch_qp_err() - Set the channel queue pair state to 'error'.
1070  */
1071 static int srpt_ch_qp_err(struct srpt_rdma_ch *ch)
1072 {
1073 	struct ib_qp_attr qp_attr;
1074 
1075 	qp_attr.qp_state = IB_QPS_ERR;
1076 	return ib_modify_qp(ch->qp, &qp_attr, IB_QP_STATE);
1077 }
1078 
1079 /**
1080  * srpt_get_send_ioctx() - Obtain an I/O context for sending to the initiator.
1081  */
1082 static struct srpt_send_ioctx *srpt_get_send_ioctx(struct srpt_rdma_ch *ch)
1083 {
1084 	struct srpt_send_ioctx *ioctx;
1085 	unsigned long flags;
1086 
1087 	BUG_ON(!ch);
1088 
1089 	ioctx = NULL;
1090 	spin_lock_irqsave(&ch->spinlock, flags);
1091 	if (!list_empty(&ch->free_list)) {
1092 		ioctx = list_first_entry(&ch->free_list,
1093 					 struct srpt_send_ioctx, free_list);
1094 		list_del(&ioctx->free_list);
1095 	}
1096 	spin_unlock_irqrestore(&ch->spinlock, flags);
1097 
1098 	if (!ioctx)
1099 		return ioctx;
1100 
1101 	BUG_ON(ioctx->ch != ch);
1102 	spin_lock_init(&ioctx->spinlock);
1103 	ioctx->state = SRPT_STATE_NEW;
1104 	ioctx->n_rdma = 0;
1105 	ioctx->n_rw_ctx = 0;
1106 	init_completion(&ioctx->tx_done);
1107 	ioctx->queue_status_only = false;
1108 	/*
1109 	 * transport_init_se_cmd() does not initialize all fields, so do it
1110 	 * here.
1111 	 */
1112 	memset(&ioctx->cmd, 0, sizeof(ioctx->cmd));
1113 	memset(&ioctx->sense_data, 0, sizeof(ioctx->sense_data));
1114 
1115 	return ioctx;
1116 }
1117 
1118 /**
1119  * srpt_abort_cmd() - Abort a SCSI command.
1120  * @ioctx:   I/O context associated with the SCSI command.
1121  * @context: Preferred execution context.
1122  */
1123 static int srpt_abort_cmd(struct srpt_send_ioctx *ioctx)
1124 {
1125 	enum srpt_command_state state;
1126 	unsigned long flags;
1127 
1128 	BUG_ON(!ioctx);
1129 
1130 	/*
1131 	 * If the command is in a state where the target core is waiting for
1132 	 * the ib_srpt driver, change the state to the next state.
1133 	 */
1134 
1135 	spin_lock_irqsave(&ioctx->spinlock, flags);
1136 	state = ioctx->state;
1137 	switch (state) {
1138 	case SRPT_STATE_NEED_DATA:
1139 		ioctx->state = SRPT_STATE_DATA_IN;
1140 		break;
1141 	case SRPT_STATE_CMD_RSP_SENT:
1142 	case SRPT_STATE_MGMT_RSP_SENT:
1143 		ioctx->state = SRPT_STATE_DONE;
1144 		break;
1145 	default:
1146 		WARN_ONCE(true, "%s: unexpected I/O context state %d\n",
1147 			  __func__, state);
1148 		break;
1149 	}
1150 	spin_unlock_irqrestore(&ioctx->spinlock, flags);
1151 
1152 	pr_debug("Aborting cmd with state %d and tag %lld\n", state,
1153 		 ioctx->cmd.tag);
1154 
1155 	switch (state) {
1156 	case SRPT_STATE_NEW:
1157 	case SRPT_STATE_DATA_IN:
1158 	case SRPT_STATE_MGMT:
1159 	case SRPT_STATE_DONE:
1160 		/*
1161 		 * Do nothing - defer abort processing until
1162 		 * srpt_queue_response() is invoked.
1163 		 */
1164 		break;
1165 	case SRPT_STATE_NEED_DATA:
1166 		pr_debug("tag %#llx: RDMA read error\n", ioctx->cmd.tag);
1167 		transport_generic_request_failure(&ioctx->cmd,
1168 					TCM_CHECK_CONDITION_ABORT_CMD);
1169 		break;
1170 	case SRPT_STATE_CMD_RSP_SENT:
1171 		/*
1172 		 * SRP_RSP sending failed or the SRP_RSP send completion has
1173 		 * not been received in time.
1174 		 */
1175 		transport_generic_free_cmd(&ioctx->cmd, 0);
1176 		break;
1177 	case SRPT_STATE_MGMT_RSP_SENT:
1178 		transport_generic_free_cmd(&ioctx->cmd, 0);
1179 		break;
1180 	default:
1181 		WARN(1, "Unexpected command state (%d)", state);
1182 		break;
1183 	}
1184 
1185 	return state;
1186 }
1187 
1188 /**
1189  * XXX: what is now target_execute_cmd used to be asynchronous, and unmapping
1190  * the data that has been transferred via IB RDMA had to be postponed until the
1191  * check_stop_free() callback.  None of this is necessary anymore and needs to
1192  * be cleaned up.
1193  */
1194 static void srpt_rdma_read_done(struct ib_cq *cq, struct ib_wc *wc)
1195 {
1196 	struct srpt_rdma_ch *ch = cq->cq_context;
1197 	struct srpt_send_ioctx *ioctx =
1198 		container_of(wc->wr_cqe, struct srpt_send_ioctx, rdma_cqe);
1199 
1200 	WARN_ON(ioctx->n_rdma <= 0);
1201 	atomic_add(ioctx->n_rdma, &ch->sq_wr_avail);
1202 	ioctx->n_rdma = 0;
1203 
1204 	if (unlikely(wc->status != IB_WC_SUCCESS)) {
1205 		pr_info("RDMA_READ for ioctx 0x%p failed with status %d\n",
1206 			ioctx, wc->status);
1207 		srpt_abort_cmd(ioctx);
1208 		return;
1209 	}
1210 
1211 	if (srpt_test_and_set_cmd_state(ioctx, SRPT_STATE_NEED_DATA,
1212 					SRPT_STATE_DATA_IN))
1213 		target_execute_cmd(&ioctx->cmd);
1214 	else
1215 		pr_err("%s[%d]: wrong state = %d\n", __func__,
1216 		       __LINE__, srpt_get_cmd_state(ioctx));
1217 }
1218 
1219 /**
1220  * srpt_build_cmd_rsp() - Build an SRP_RSP response.
1221  * @ch: RDMA channel through which the request has been received.
1222  * @ioctx: I/O context associated with the SRP_CMD request. The response will
1223  *   be built in the buffer ioctx->buf points at and hence this function will
1224  *   overwrite the request data.
1225  * @tag: tag of the request for which this response is being generated.
1226  * @status: value for the STATUS field of the SRP_RSP information unit.
1227  *
1228  * Returns the size in bytes of the SRP_RSP response.
1229  *
1230  * An SRP_RSP response contains a SCSI status or service response. See also
1231  * section 6.9 in the SRP r16a document for the format of an SRP_RSP
1232  * response. See also SPC-2 for more information about sense data.
1233  */
1234 static int srpt_build_cmd_rsp(struct srpt_rdma_ch *ch,
1235 			      struct srpt_send_ioctx *ioctx, u64 tag,
1236 			      int status)
1237 {
1238 	struct srp_rsp *srp_rsp;
1239 	const u8 *sense_data;
1240 	int sense_data_len, max_sense_len;
1241 
1242 	/*
1243 	 * The lowest bit of all SAM-3 status codes is zero (see also
1244 	 * paragraph 5.3 in SAM-3).
1245 	 */
1246 	WARN_ON(status & 1);
1247 
1248 	srp_rsp = ioctx->ioctx.buf;
1249 	BUG_ON(!srp_rsp);
1250 
1251 	sense_data = ioctx->sense_data;
1252 	sense_data_len = ioctx->cmd.scsi_sense_length;
1253 	WARN_ON(sense_data_len > sizeof(ioctx->sense_data));
1254 
1255 	memset(srp_rsp, 0, sizeof(*srp_rsp));
1256 	srp_rsp->opcode = SRP_RSP;
1257 	srp_rsp->req_lim_delta =
1258 		cpu_to_be32(1 + atomic_xchg(&ch->req_lim_delta, 0));
1259 	srp_rsp->tag = tag;
1260 	srp_rsp->status = status;
1261 
1262 	if (sense_data_len) {
1263 		BUILD_BUG_ON(MIN_MAX_RSP_SIZE <= sizeof(*srp_rsp));
1264 		max_sense_len = ch->max_ti_iu_len - sizeof(*srp_rsp);
1265 		if (sense_data_len > max_sense_len) {
1266 			pr_warn("truncated sense data from %d to %d"
1267 				" bytes\n", sense_data_len, max_sense_len);
1268 			sense_data_len = max_sense_len;
1269 		}
1270 
1271 		srp_rsp->flags |= SRP_RSP_FLAG_SNSVALID;
1272 		srp_rsp->sense_data_len = cpu_to_be32(sense_data_len);
1273 		memcpy(srp_rsp + 1, sense_data, sense_data_len);
1274 	}
1275 
1276 	return sizeof(*srp_rsp) + sense_data_len;
1277 }
1278 
1279 /**
1280  * srpt_build_tskmgmt_rsp() - Build a task management response.
1281  * @ch:       RDMA channel through which the request has been received.
1282  * @ioctx:    I/O context in which the SRP_RSP response will be built.
1283  * @rsp_code: RSP_CODE that will be stored in the response.
1284  * @tag:      Tag of the request for which this response is being generated.
1285  *
1286  * Returns the size in bytes of the SRP_RSP response.
1287  *
1288  * An SRP_RSP response contains a SCSI status or service response. See also
1289  * section 6.9 in the SRP r16a document for the format of an SRP_RSP
1290  * response.
1291  */
1292 static int srpt_build_tskmgmt_rsp(struct srpt_rdma_ch *ch,
1293 				  struct srpt_send_ioctx *ioctx,
1294 				  u8 rsp_code, u64 tag)
1295 {
1296 	struct srp_rsp *srp_rsp;
1297 	int resp_data_len;
1298 	int resp_len;
1299 
1300 	resp_data_len = 4;
1301 	resp_len = sizeof(*srp_rsp) + resp_data_len;
1302 
1303 	srp_rsp = ioctx->ioctx.buf;
1304 	BUG_ON(!srp_rsp);
1305 	memset(srp_rsp, 0, sizeof(*srp_rsp));
1306 
1307 	srp_rsp->opcode = SRP_RSP;
1308 	srp_rsp->req_lim_delta =
1309 		cpu_to_be32(1 + atomic_xchg(&ch->req_lim_delta, 0));
1310 	srp_rsp->tag = tag;
1311 
1312 	srp_rsp->flags |= SRP_RSP_FLAG_RSPVALID;
1313 	srp_rsp->resp_data_len = cpu_to_be32(resp_data_len);
1314 	srp_rsp->data[3] = rsp_code;
1315 
1316 	return resp_len;
1317 }
1318 
1319 static int srpt_check_stop_free(struct se_cmd *cmd)
1320 {
1321 	struct srpt_send_ioctx *ioctx = container_of(cmd,
1322 				struct srpt_send_ioctx, cmd);
1323 
1324 	return target_put_sess_cmd(&ioctx->cmd);
1325 }
1326 
1327 /**
1328  * srpt_handle_cmd() - Process SRP_CMD.
1329  */
1330 static void srpt_handle_cmd(struct srpt_rdma_ch *ch,
1331 			    struct srpt_recv_ioctx *recv_ioctx,
1332 			    struct srpt_send_ioctx *send_ioctx)
1333 {
1334 	struct se_cmd *cmd;
1335 	struct srp_cmd *srp_cmd;
1336 	struct scatterlist *sg = NULL;
1337 	unsigned sg_cnt = 0;
1338 	u64 data_len;
1339 	enum dma_data_direction dir;
1340 	int rc;
1341 
1342 	BUG_ON(!send_ioctx);
1343 
1344 	srp_cmd = recv_ioctx->ioctx.buf;
1345 	cmd = &send_ioctx->cmd;
1346 	cmd->tag = srp_cmd->tag;
1347 
1348 	switch (srp_cmd->task_attr) {
1349 	case SRP_CMD_SIMPLE_Q:
1350 		cmd->sam_task_attr = TCM_SIMPLE_TAG;
1351 		break;
1352 	case SRP_CMD_ORDERED_Q:
1353 	default:
1354 		cmd->sam_task_attr = TCM_ORDERED_TAG;
1355 		break;
1356 	case SRP_CMD_HEAD_OF_Q:
1357 		cmd->sam_task_attr = TCM_HEAD_TAG;
1358 		break;
1359 	case SRP_CMD_ACA:
1360 		cmd->sam_task_attr = TCM_ACA_TAG;
1361 		break;
1362 	}
1363 
1364 	rc = srpt_get_desc_tbl(send_ioctx, srp_cmd, &dir, &sg, &sg_cnt,
1365 			&data_len);
1366 	if (rc) {
1367 		if (rc != -EAGAIN) {
1368 			pr_err("0x%llx: parsing SRP descriptor table failed.\n",
1369 			       srp_cmd->tag);
1370 		}
1371 		goto release_ioctx;
1372 	}
1373 
1374 	rc = target_submit_cmd_map_sgls(cmd, ch->sess, srp_cmd->cdb,
1375 			       &send_ioctx->sense_data[0],
1376 			       scsilun_to_int(&srp_cmd->lun), data_len,
1377 			       TCM_SIMPLE_TAG, dir, TARGET_SCF_ACK_KREF,
1378 			       sg, sg_cnt, NULL, 0, NULL, 0);
1379 	if (rc != 0) {
1380 		pr_debug("target_submit_cmd() returned %d for tag %#llx\n", rc,
1381 			 srp_cmd->tag);
1382 		goto release_ioctx;
1383 	}
1384 	return;
1385 
1386 release_ioctx:
1387 	send_ioctx->state = SRPT_STATE_DONE;
1388 	srpt_release_cmd(cmd);
1389 }
1390 
1391 static int srp_tmr_to_tcm(int fn)
1392 {
1393 	switch (fn) {
1394 	case SRP_TSK_ABORT_TASK:
1395 		return TMR_ABORT_TASK;
1396 	case SRP_TSK_ABORT_TASK_SET:
1397 		return TMR_ABORT_TASK_SET;
1398 	case SRP_TSK_CLEAR_TASK_SET:
1399 		return TMR_CLEAR_TASK_SET;
1400 	case SRP_TSK_LUN_RESET:
1401 		return TMR_LUN_RESET;
1402 	case SRP_TSK_CLEAR_ACA:
1403 		return TMR_CLEAR_ACA;
1404 	default:
1405 		return -1;
1406 	}
1407 }
1408 
1409 /**
1410  * srpt_handle_tsk_mgmt() - Process an SRP_TSK_MGMT information unit.
1411  *
1412  * Returns 0 if and only if the request will be processed by the target core.
1413  *
1414  * For more information about SRP_TSK_MGMT information units, see also section
1415  * 6.7 in the SRP r16a document.
1416  */
1417 static void srpt_handle_tsk_mgmt(struct srpt_rdma_ch *ch,
1418 				 struct srpt_recv_ioctx *recv_ioctx,
1419 				 struct srpt_send_ioctx *send_ioctx)
1420 {
1421 	struct srp_tsk_mgmt *srp_tsk;
1422 	struct se_cmd *cmd;
1423 	struct se_session *sess = ch->sess;
1424 	int tcm_tmr;
1425 	int rc;
1426 
1427 	BUG_ON(!send_ioctx);
1428 
1429 	srp_tsk = recv_ioctx->ioctx.buf;
1430 	cmd = &send_ioctx->cmd;
1431 
1432 	pr_debug("recv tsk_mgmt fn %d for task_tag %lld and cmd tag %lld"
1433 		 " cm_id %p sess %p\n", srp_tsk->tsk_mgmt_func,
1434 		 srp_tsk->task_tag, srp_tsk->tag, ch->cm_id, ch->sess);
1435 
1436 	srpt_set_cmd_state(send_ioctx, SRPT_STATE_MGMT);
1437 	send_ioctx->cmd.tag = srp_tsk->tag;
1438 	tcm_tmr = srp_tmr_to_tcm(srp_tsk->tsk_mgmt_func);
1439 	rc = target_submit_tmr(&send_ioctx->cmd, sess, NULL,
1440 			       scsilun_to_int(&srp_tsk->lun), srp_tsk, tcm_tmr,
1441 			       GFP_KERNEL, srp_tsk->task_tag,
1442 			       TARGET_SCF_ACK_KREF);
1443 	if (rc != 0) {
1444 		send_ioctx->cmd.se_tmr_req->response = TMR_FUNCTION_REJECTED;
1445 		goto fail;
1446 	}
1447 	return;
1448 fail:
1449 	transport_send_check_condition_and_sense(cmd, 0, 0); // XXX:
1450 }
1451 
1452 /**
1453  * srpt_handle_new_iu() - Process a newly received information unit.
1454  * @ch:    RDMA channel through which the information unit has been received.
1455  * @ioctx: SRPT I/O context associated with the information unit.
1456  */
1457 static void srpt_handle_new_iu(struct srpt_rdma_ch *ch,
1458 			       struct srpt_recv_ioctx *recv_ioctx,
1459 			       struct srpt_send_ioctx *send_ioctx)
1460 {
1461 	struct srp_cmd *srp_cmd;
1462 
1463 	BUG_ON(!ch);
1464 	BUG_ON(!recv_ioctx);
1465 
1466 	ib_dma_sync_single_for_cpu(ch->sport->sdev->device,
1467 				   recv_ioctx->ioctx.dma, srp_max_req_size,
1468 				   DMA_FROM_DEVICE);
1469 
1470 	if (unlikely(ch->state == CH_CONNECTING))
1471 		goto out_wait;
1472 
1473 	if (unlikely(ch->state != CH_LIVE))
1474 		return;
1475 
1476 	srp_cmd = recv_ioctx->ioctx.buf;
1477 	if (srp_cmd->opcode == SRP_CMD || srp_cmd->opcode == SRP_TSK_MGMT) {
1478 		if (!send_ioctx) {
1479 			if (!list_empty(&ch->cmd_wait_list))
1480 				goto out_wait;
1481 			send_ioctx = srpt_get_send_ioctx(ch);
1482 		}
1483 		if (unlikely(!send_ioctx))
1484 			goto out_wait;
1485 	}
1486 
1487 	switch (srp_cmd->opcode) {
1488 	case SRP_CMD:
1489 		srpt_handle_cmd(ch, recv_ioctx, send_ioctx);
1490 		break;
1491 	case SRP_TSK_MGMT:
1492 		srpt_handle_tsk_mgmt(ch, recv_ioctx, send_ioctx);
1493 		break;
1494 	case SRP_I_LOGOUT:
1495 		pr_err("Not yet implemented: SRP_I_LOGOUT\n");
1496 		break;
1497 	case SRP_CRED_RSP:
1498 		pr_debug("received SRP_CRED_RSP\n");
1499 		break;
1500 	case SRP_AER_RSP:
1501 		pr_debug("received SRP_AER_RSP\n");
1502 		break;
1503 	case SRP_RSP:
1504 		pr_err("Received SRP_RSP\n");
1505 		break;
1506 	default:
1507 		pr_err("received IU with unknown opcode 0x%x\n",
1508 		       srp_cmd->opcode);
1509 		break;
1510 	}
1511 
1512 	srpt_post_recv(ch->sport->sdev, recv_ioctx);
1513 	return;
1514 
1515 out_wait:
1516 	list_add_tail(&recv_ioctx->wait_list, &ch->cmd_wait_list);
1517 }
1518 
1519 static void srpt_recv_done(struct ib_cq *cq, struct ib_wc *wc)
1520 {
1521 	struct srpt_rdma_ch *ch = cq->cq_context;
1522 	struct srpt_recv_ioctx *ioctx =
1523 		container_of(wc->wr_cqe, struct srpt_recv_ioctx, ioctx.cqe);
1524 
1525 	if (wc->status == IB_WC_SUCCESS) {
1526 		int req_lim;
1527 
1528 		req_lim = atomic_dec_return(&ch->req_lim);
1529 		if (unlikely(req_lim < 0))
1530 			pr_err("req_lim = %d < 0\n", req_lim);
1531 		srpt_handle_new_iu(ch, ioctx, NULL);
1532 	} else {
1533 		pr_info("receiving failed for ioctx %p with status %d\n",
1534 			ioctx, wc->status);
1535 	}
1536 }
1537 
1538 /*
1539  * This function must be called from the context in which RDMA completions are
1540  * processed because it accesses the wait list without protection against
1541  * access from other threads.
1542  */
1543 static void srpt_process_wait_list(struct srpt_rdma_ch *ch)
1544 {
1545 	struct srpt_send_ioctx *ioctx;
1546 
1547 	while (!list_empty(&ch->cmd_wait_list) &&
1548 	       ch->state >= CH_LIVE &&
1549 	       (ioctx = srpt_get_send_ioctx(ch)) != NULL) {
1550 		struct srpt_recv_ioctx *recv_ioctx;
1551 
1552 		recv_ioctx = list_first_entry(&ch->cmd_wait_list,
1553 					      struct srpt_recv_ioctx,
1554 					      wait_list);
1555 		list_del(&recv_ioctx->wait_list);
1556 		srpt_handle_new_iu(ch, recv_ioctx, ioctx);
1557 	}
1558 }
1559 
1560 /**
1561  * Note: Although this has not yet been observed during tests, at least in
1562  * theory it is possible that the srpt_get_send_ioctx() call invoked by
1563  * srpt_handle_new_iu() fails. This is possible because the req_lim_delta
1564  * value in each response is set to one, and it is possible that this response
1565  * makes the initiator send a new request before the send completion for that
1566  * response has been processed. This could e.g. happen if the call to
1567  * srpt_put_send_iotcx() is delayed because of a higher priority interrupt or
1568  * if IB retransmission causes generation of the send completion to be
1569  * delayed. Incoming information units for which srpt_get_send_ioctx() fails
1570  * are queued on cmd_wait_list. The code below processes these delayed
1571  * requests one at a time.
1572  */
1573 static void srpt_send_done(struct ib_cq *cq, struct ib_wc *wc)
1574 {
1575 	struct srpt_rdma_ch *ch = cq->cq_context;
1576 	struct srpt_send_ioctx *ioctx =
1577 		container_of(wc->wr_cqe, struct srpt_send_ioctx, ioctx.cqe);
1578 	enum srpt_command_state state;
1579 
1580 	state = srpt_set_cmd_state(ioctx, SRPT_STATE_DONE);
1581 
1582 	WARN_ON(state != SRPT_STATE_CMD_RSP_SENT &&
1583 		state != SRPT_STATE_MGMT_RSP_SENT);
1584 
1585 	atomic_add(1 + ioctx->n_rdma, &ch->sq_wr_avail);
1586 
1587 	if (wc->status != IB_WC_SUCCESS)
1588 		pr_info("sending response for ioctx 0x%p failed"
1589 			" with status %d\n", ioctx, wc->status);
1590 
1591 	if (state != SRPT_STATE_DONE) {
1592 		transport_generic_free_cmd(&ioctx->cmd, 0);
1593 	} else {
1594 		pr_err("IB completion has been received too late for"
1595 		       " wr_id = %u.\n", ioctx->ioctx.index);
1596 	}
1597 
1598 	srpt_process_wait_list(ch);
1599 }
1600 
1601 /**
1602  * srpt_create_ch_ib() - Create receive and send completion queues.
1603  */
1604 static int srpt_create_ch_ib(struct srpt_rdma_ch *ch)
1605 {
1606 	struct ib_qp_init_attr *qp_init;
1607 	struct srpt_port *sport = ch->sport;
1608 	struct srpt_device *sdev = sport->sdev;
1609 	const struct ib_device_attr *attrs = &sdev->device->attrs;
1610 	u32 srp_sq_size = sport->port_attrib.srp_sq_size;
1611 	int ret;
1612 
1613 	WARN_ON(ch->rq_size < 1);
1614 
1615 	ret = -ENOMEM;
1616 	qp_init = kzalloc(sizeof(*qp_init), GFP_KERNEL);
1617 	if (!qp_init)
1618 		goto out;
1619 
1620 retry:
1621 	ch->cq = ib_alloc_cq(sdev->device, ch, ch->rq_size + srp_sq_size,
1622 			0 /* XXX: spread CQs */, IB_POLL_WORKQUEUE);
1623 	if (IS_ERR(ch->cq)) {
1624 		ret = PTR_ERR(ch->cq);
1625 		pr_err("failed to create CQ cqe= %d ret= %d\n",
1626 		       ch->rq_size + srp_sq_size, ret);
1627 		goto out;
1628 	}
1629 
1630 	qp_init->qp_context = (void *)ch;
1631 	qp_init->event_handler
1632 		= (void(*)(struct ib_event *, void*))srpt_qp_event;
1633 	qp_init->send_cq = ch->cq;
1634 	qp_init->recv_cq = ch->cq;
1635 	qp_init->srq = sdev->srq;
1636 	qp_init->sq_sig_type = IB_SIGNAL_REQ_WR;
1637 	qp_init->qp_type = IB_QPT_RC;
1638 	/*
1639 	 * We divide up our send queue size into half SEND WRs to send the
1640 	 * completions, and half R/W contexts to actually do the RDMA
1641 	 * READ/WRITE transfers.  Note that we need to allocate CQ slots for
1642 	 * both both, as RDMA contexts will also post completions for the
1643 	 * RDMA READ case.
1644 	 */
1645 	qp_init->cap.max_send_wr = srp_sq_size / 2;
1646 	qp_init->cap.max_rdma_ctxs = srp_sq_size / 2;
1647 	qp_init->cap.max_send_sge = min(attrs->max_sge, SRPT_MAX_SG_PER_WQE);
1648 	qp_init->port_num = ch->sport->port;
1649 
1650 	ch->qp = ib_create_qp(sdev->pd, qp_init);
1651 	if (IS_ERR(ch->qp)) {
1652 		ret = PTR_ERR(ch->qp);
1653 		if (ret == -ENOMEM) {
1654 			srp_sq_size /= 2;
1655 			if (srp_sq_size >= MIN_SRPT_SQ_SIZE) {
1656 				ib_destroy_cq(ch->cq);
1657 				goto retry;
1658 			}
1659 		}
1660 		pr_err("failed to create_qp ret= %d\n", ret);
1661 		goto err_destroy_cq;
1662 	}
1663 
1664 	atomic_set(&ch->sq_wr_avail, qp_init->cap.max_send_wr);
1665 
1666 	pr_debug("%s: max_cqe= %d max_sge= %d sq_size = %d cm_id= %p\n",
1667 		 __func__, ch->cq->cqe, qp_init->cap.max_send_sge,
1668 		 qp_init->cap.max_send_wr, ch->cm_id);
1669 
1670 	ret = srpt_init_ch_qp(ch, ch->qp);
1671 	if (ret)
1672 		goto err_destroy_qp;
1673 
1674 out:
1675 	kfree(qp_init);
1676 	return ret;
1677 
1678 err_destroy_qp:
1679 	ib_destroy_qp(ch->qp);
1680 err_destroy_cq:
1681 	ib_free_cq(ch->cq);
1682 	goto out;
1683 }
1684 
1685 static void srpt_destroy_ch_ib(struct srpt_rdma_ch *ch)
1686 {
1687 	ib_destroy_qp(ch->qp);
1688 	ib_free_cq(ch->cq);
1689 }
1690 
1691 /**
1692  * srpt_close_ch() - Close an RDMA channel.
1693  *
1694  * Make sure all resources associated with the channel will be deallocated at
1695  * an appropriate time.
1696  *
1697  * Returns true if and only if the channel state has been modified into
1698  * CH_DRAINING.
1699  */
1700 static bool srpt_close_ch(struct srpt_rdma_ch *ch)
1701 {
1702 	int ret;
1703 
1704 	if (!srpt_set_ch_state(ch, CH_DRAINING)) {
1705 		pr_debug("%s-%d: already closed\n", ch->sess_name,
1706 			 ch->qp->qp_num);
1707 		return false;
1708 	}
1709 
1710 	kref_get(&ch->kref);
1711 
1712 	ret = srpt_ch_qp_err(ch);
1713 	if (ret < 0)
1714 		pr_err("%s-%d: changing queue pair into error state failed: %d\n",
1715 		       ch->sess_name, ch->qp->qp_num, ret);
1716 
1717 	pr_debug("%s-%d: queued zerolength write\n", ch->sess_name,
1718 		 ch->qp->qp_num);
1719 	ret = srpt_zerolength_write(ch);
1720 	if (ret < 0) {
1721 		pr_err("%s-%d: queuing zero-length write failed: %d\n",
1722 		       ch->sess_name, ch->qp->qp_num, ret);
1723 		if (srpt_set_ch_state(ch, CH_DISCONNECTED))
1724 			schedule_work(&ch->release_work);
1725 		else
1726 			WARN_ON_ONCE(true);
1727 	}
1728 
1729 	kref_put(&ch->kref, srpt_free_ch);
1730 
1731 	return true;
1732 }
1733 
1734 /*
1735  * Change the channel state into CH_DISCONNECTING. If a channel has not yet
1736  * reached the connected state, close it. If a channel is in the connected
1737  * state, send a DREQ. If a DREQ has been received, send a DREP. Note: it is
1738  * the responsibility of the caller to ensure that this function is not
1739  * invoked concurrently with the code that accepts a connection. This means
1740  * that this function must either be invoked from inside a CM callback
1741  * function or that it must be invoked with the srpt_port.mutex held.
1742  */
1743 static int srpt_disconnect_ch(struct srpt_rdma_ch *ch)
1744 {
1745 	int ret;
1746 
1747 	if (!srpt_set_ch_state(ch, CH_DISCONNECTING))
1748 		return -ENOTCONN;
1749 
1750 	ret = ib_send_cm_dreq(ch->cm_id, NULL, 0);
1751 	if (ret < 0)
1752 		ret = ib_send_cm_drep(ch->cm_id, NULL, 0);
1753 
1754 	if (ret < 0 && srpt_close_ch(ch))
1755 		ret = 0;
1756 
1757 	return ret;
1758 }
1759 
1760 static void __srpt_close_all_ch(struct srpt_device *sdev)
1761 {
1762 	struct srpt_rdma_ch *ch;
1763 
1764 	lockdep_assert_held(&sdev->mutex);
1765 
1766 	list_for_each_entry(ch, &sdev->rch_list, list) {
1767 		if (srpt_disconnect_ch(ch) >= 0)
1768 			pr_info("Closing channel %s-%d because target %s has been disabled\n",
1769 				ch->sess_name, ch->qp->qp_num,
1770 				sdev->device->name);
1771 		srpt_close_ch(ch);
1772 	}
1773 }
1774 
1775 static void srpt_free_ch(struct kref *kref)
1776 {
1777 	struct srpt_rdma_ch *ch = container_of(kref, struct srpt_rdma_ch, kref);
1778 
1779 	kfree(ch);
1780 }
1781 
1782 static void srpt_release_channel_work(struct work_struct *w)
1783 {
1784 	struct srpt_rdma_ch *ch;
1785 	struct srpt_device *sdev;
1786 	struct se_session *se_sess;
1787 
1788 	ch = container_of(w, struct srpt_rdma_ch, release_work);
1789 	pr_debug("%s: %s-%d; release_done = %p\n", __func__, ch->sess_name,
1790 		 ch->qp->qp_num, ch->release_done);
1791 
1792 	sdev = ch->sport->sdev;
1793 	BUG_ON(!sdev);
1794 
1795 	se_sess = ch->sess;
1796 	BUG_ON(!se_sess);
1797 
1798 	target_sess_cmd_list_set_waiting(se_sess);
1799 	target_wait_for_sess_cmds(se_sess);
1800 
1801 	transport_deregister_session_configfs(se_sess);
1802 	transport_deregister_session(se_sess);
1803 	ch->sess = NULL;
1804 
1805 	ib_destroy_cm_id(ch->cm_id);
1806 
1807 	srpt_destroy_ch_ib(ch);
1808 
1809 	srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_ring,
1810 			     ch->sport->sdev, ch->rq_size,
1811 			     ch->rsp_size, DMA_TO_DEVICE);
1812 
1813 	mutex_lock(&sdev->mutex);
1814 	list_del_init(&ch->list);
1815 	if (ch->release_done)
1816 		complete(ch->release_done);
1817 	mutex_unlock(&sdev->mutex);
1818 
1819 	wake_up(&sdev->ch_releaseQ);
1820 
1821 	kref_put(&ch->kref, srpt_free_ch);
1822 }
1823 
1824 /**
1825  * srpt_cm_req_recv() - Process the event IB_CM_REQ_RECEIVED.
1826  *
1827  * Ownership of the cm_id is transferred to the target session if this
1828  * functions returns zero. Otherwise the caller remains the owner of cm_id.
1829  */
1830 static int srpt_cm_req_recv(struct ib_cm_id *cm_id,
1831 			    struct ib_cm_req_event_param *param,
1832 			    void *private_data)
1833 {
1834 	struct srpt_device *sdev = cm_id->context;
1835 	struct srpt_port *sport = &sdev->port[param->port - 1];
1836 	struct srp_login_req *req;
1837 	struct srp_login_rsp *rsp;
1838 	struct srp_login_rej *rej;
1839 	struct ib_cm_rep_param *rep_param;
1840 	struct srpt_rdma_ch *ch, *tmp_ch;
1841 	u32 it_iu_len;
1842 	int i, ret = 0;
1843 	unsigned char *p;
1844 
1845 	WARN_ON_ONCE(irqs_disabled());
1846 
1847 	if (WARN_ON(!sdev || !private_data))
1848 		return -EINVAL;
1849 
1850 	req = (struct srp_login_req *)private_data;
1851 
1852 	it_iu_len = be32_to_cpu(req->req_it_iu_len);
1853 
1854 	pr_info("Received SRP_LOGIN_REQ with i_port_id 0x%llx:0x%llx,"
1855 		" t_port_id 0x%llx:0x%llx and it_iu_len %d on port %d"
1856 		" (guid=0x%llx:0x%llx)\n",
1857 		be64_to_cpu(*(__be64 *)&req->initiator_port_id[0]),
1858 		be64_to_cpu(*(__be64 *)&req->initiator_port_id[8]),
1859 		be64_to_cpu(*(__be64 *)&req->target_port_id[0]),
1860 		be64_to_cpu(*(__be64 *)&req->target_port_id[8]),
1861 		it_iu_len,
1862 		param->port,
1863 		be64_to_cpu(*(__be64 *)&sdev->port[param->port - 1].gid.raw[0]),
1864 		be64_to_cpu(*(__be64 *)&sdev->port[param->port - 1].gid.raw[8]));
1865 
1866 	rsp = kzalloc(sizeof(*rsp), GFP_KERNEL);
1867 	rej = kzalloc(sizeof(*rej), GFP_KERNEL);
1868 	rep_param = kzalloc(sizeof(*rep_param), GFP_KERNEL);
1869 
1870 	if (!rsp || !rej || !rep_param) {
1871 		ret = -ENOMEM;
1872 		goto out;
1873 	}
1874 
1875 	if (it_iu_len > srp_max_req_size || it_iu_len < 64) {
1876 		rej->reason = cpu_to_be32(
1877 			      SRP_LOGIN_REJ_REQ_IT_IU_LENGTH_TOO_LARGE);
1878 		ret = -EINVAL;
1879 		pr_err("rejected SRP_LOGIN_REQ because its"
1880 		       " length (%d bytes) is out of range (%d .. %d)\n",
1881 		       it_iu_len, 64, srp_max_req_size);
1882 		goto reject;
1883 	}
1884 
1885 	if (!sport->enabled) {
1886 		rej->reason = cpu_to_be32(
1887 			      SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
1888 		ret = -EINVAL;
1889 		pr_err("rejected SRP_LOGIN_REQ because the target port"
1890 		       " has not yet been enabled\n");
1891 		goto reject;
1892 	}
1893 
1894 	if ((req->req_flags & SRP_MTCH_ACTION) == SRP_MULTICHAN_SINGLE) {
1895 		rsp->rsp_flags = SRP_LOGIN_RSP_MULTICHAN_NO_CHAN;
1896 
1897 		mutex_lock(&sdev->mutex);
1898 
1899 		list_for_each_entry_safe(ch, tmp_ch, &sdev->rch_list, list) {
1900 			if (!memcmp(ch->i_port_id, req->initiator_port_id, 16)
1901 			    && !memcmp(ch->t_port_id, req->target_port_id, 16)
1902 			    && param->port == ch->sport->port
1903 			    && param->listen_id == ch->sport->sdev->cm_id
1904 			    && ch->cm_id) {
1905 				if (srpt_disconnect_ch(ch) < 0)
1906 					continue;
1907 				pr_info("Relogin - closed existing channel %s\n",
1908 					ch->sess_name);
1909 				rsp->rsp_flags =
1910 					SRP_LOGIN_RSP_MULTICHAN_TERMINATED;
1911 			}
1912 		}
1913 
1914 		mutex_unlock(&sdev->mutex);
1915 
1916 	} else
1917 		rsp->rsp_flags = SRP_LOGIN_RSP_MULTICHAN_MAINTAINED;
1918 
1919 	if (*(__be64 *)req->target_port_id != cpu_to_be64(srpt_service_guid)
1920 	    || *(__be64 *)(req->target_port_id + 8) !=
1921 	       cpu_to_be64(srpt_service_guid)) {
1922 		rej->reason = cpu_to_be32(
1923 			      SRP_LOGIN_REJ_UNABLE_ASSOCIATE_CHANNEL);
1924 		ret = -ENOMEM;
1925 		pr_err("rejected SRP_LOGIN_REQ because it"
1926 		       " has an invalid target port identifier.\n");
1927 		goto reject;
1928 	}
1929 
1930 	ch = kzalloc(sizeof(*ch), GFP_KERNEL);
1931 	if (!ch) {
1932 		rej->reason = cpu_to_be32(
1933 			      SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
1934 		pr_err("rejected SRP_LOGIN_REQ because no memory.\n");
1935 		ret = -ENOMEM;
1936 		goto reject;
1937 	}
1938 
1939 	kref_init(&ch->kref);
1940 	ch->zw_cqe.done = srpt_zerolength_write_done;
1941 	INIT_WORK(&ch->release_work, srpt_release_channel_work);
1942 	memcpy(ch->i_port_id, req->initiator_port_id, 16);
1943 	memcpy(ch->t_port_id, req->target_port_id, 16);
1944 	ch->sport = &sdev->port[param->port - 1];
1945 	ch->cm_id = cm_id;
1946 	cm_id->context = ch;
1947 	/*
1948 	 * Avoid QUEUE_FULL conditions by limiting the number of buffers used
1949 	 * for the SRP protocol to the command queue size.
1950 	 */
1951 	ch->rq_size = SRPT_RQ_SIZE;
1952 	spin_lock_init(&ch->spinlock);
1953 	ch->state = CH_CONNECTING;
1954 	INIT_LIST_HEAD(&ch->cmd_wait_list);
1955 	ch->rsp_size = ch->sport->port_attrib.srp_max_rsp_size;
1956 
1957 	ch->ioctx_ring = (struct srpt_send_ioctx **)
1958 		srpt_alloc_ioctx_ring(ch->sport->sdev, ch->rq_size,
1959 				      sizeof(*ch->ioctx_ring[0]),
1960 				      ch->rsp_size, DMA_TO_DEVICE);
1961 	if (!ch->ioctx_ring)
1962 		goto free_ch;
1963 
1964 	INIT_LIST_HEAD(&ch->free_list);
1965 	for (i = 0; i < ch->rq_size; i++) {
1966 		ch->ioctx_ring[i]->ch = ch;
1967 		list_add_tail(&ch->ioctx_ring[i]->free_list, &ch->free_list);
1968 	}
1969 
1970 	ret = srpt_create_ch_ib(ch);
1971 	if (ret) {
1972 		rej->reason = cpu_to_be32(
1973 			      SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
1974 		pr_err("rejected SRP_LOGIN_REQ because creating"
1975 		       " a new RDMA channel failed.\n");
1976 		goto free_ring;
1977 	}
1978 
1979 	ret = srpt_ch_qp_rtr(ch, ch->qp);
1980 	if (ret) {
1981 		rej->reason = cpu_to_be32(SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
1982 		pr_err("rejected SRP_LOGIN_REQ because enabling"
1983 		       " RTR failed (error code = %d)\n", ret);
1984 		goto destroy_ib;
1985 	}
1986 
1987 	/*
1988 	 * Use the initator port identifier as the session name, when
1989 	 * checking against se_node_acl->initiatorname[] this can be
1990 	 * with or without preceeding '0x'.
1991 	 */
1992 	snprintf(ch->sess_name, sizeof(ch->sess_name), "0x%016llx%016llx",
1993 			be64_to_cpu(*(__be64 *)ch->i_port_id),
1994 			be64_to_cpu(*(__be64 *)(ch->i_port_id + 8)));
1995 
1996 	pr_debug("registering session %s\n", ch->sess_name);
1997 	p = &ch->sess_name[0];
1998 
1999 try_again:
2000 	ch->sess = target_alloc_session(&sport->port_tpg_1, 0, 0,
2001 					TARGET_PROT_NORMAL, p, ch, NULL);
2002 	if (IS_ERR(ch->sess)) {
2003 		pr_info("Rejected login because no ACL has been"
2004 			" configured yet for initiator %s.\n", p);
2005 		/*
2006 		 * XXX: Hack to retry of ch->i_port_id without leading '0x'
2007 		 */
2008 		if (p == &ch->sess_name[0]) {
2009 			p += 2;
2010 			goto try_again;
2011 		}
2012 		rej->reason = cpu_to_be32((PTR_ERR(ch->sess) == -ENOMEM) ?
2013 				SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES :
2014 				SRP_LOGIN_REJ_CHANNEL_LIMIT_REACHED);
2015 		goto destroy_ib;
2016 	}
2017 
2018 	pr_debug("Establish connection sess=%p name=%s cm_id=%p\n", ch->sess,
2019 		 ch->sess_name, ch->cm_id);
2020 
2021 	/* create srp_login_response */
2022 	rsp->opcode = SRP_LOGIN_RSP;
2023 	rsp->tag = req->tag;
2024 	rsp->max_it_iu_len = req->req_it_iu_len;
2025 	rsp->max_ti_iu_len = req->req_it_iu_len;
2026 	ch->max_ti_iu_len = it_iu_len;
2027 	rsp->buf_fmt = cpu_to_be16(SRP_BUF_FORMAT_DIRECT
2028 				   | SRP_BUF_FORMAT_INDIRECT);
2029 	rsp->req_lim_delta = cpu_to_be32(ch->rq_size);
2030 	atomic_set(&ch->req_lim, ch->rq_size);
2031 	atomic_set(&ch->req_lim_delta, 0);
2032 
2033 	/* create cm reply */
2034 	rep_param->qp_num = ch->qp->qp_num;
2035 	rep_param->private_data = (void *)rsp;
2036 	rep_param->private_data_len = sizeof(*rsp);
2037 	rep_param->rnr_retry_count = 7;
2038 	rep_param->flow_control = 1;
2039 	rep_param->failover_accepted = 0;
2040 	rep_param->srq = 1;
2041 	rep_param->responder_resources = 4;
2042 	rep_param->initiator_depth = 4;
2043 
2044 	ret = ib_send_cm_rep(cm_id, rep_param);
2045 	if (ret) {
2046 		pr_err("sending SRP_LOGIN_REQ response failed"
2047 		       " (error code = %d)\n", ret);
2048 		goto release_channel;
2049 	}
2050 
2051 	mutex_lock(&sdev->mutex);
2052 	list_add_tail(&ch->list, &sdev->rch_list);
2053 	mutex_unlock(&sdev->mutex);
2054 
2055 	goto out;
2056 
2057 release_channel:
2058 	srpt_disconnect_ch(ch);
2059 	transport_deregister_session_configfs(ch->sess);
2060 	transport_deregister_session(ch->sess);
2061 	ch->sess = NULL;
2062 
2063 destroy_ib:
2064 	srpt_destroy_ch_ib(ch);
2065 
2066 free_ring:
2067 	srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_ring,
2068 			     ch->sport->sdev, ch->rq_size,
2069 			     ch->rsp_size, DMA_TO_DEVICE);
2070 free_ch:
2071 	kfree(ch);
2072 
2073 reject:
2074 	rej->opcode = SRP_LOGIN_REJ;
2075 	rej->tag = req->tag;
2076 	rej->buf_fmt = cpu_to_be16(SRP_BUF_FORMAT_DIRECT
2077 				   | SRP_BUF_FORMAT_INDIRECT);
2078 
2079 	ib_send_cm_rej(cm_id, IB_CM_REJ_CONSUMER_DEFINED, NULL, 0,
2080 			     (void *)rej, sizeof(*rej));
2081 
2082 out:
2083 	kfree(rep_param);
2084 	kfree(rsp);
2085 	kfree(rej);
2086 
2087 	return ret;
2088 }
2089 
2090 static void srpt_cm_rej_recv(struct srpt_rdma_ch *ch,
2091 			     enum ib_cm_rej_reason reason,
2092 			     const u8 *private_data,
2093 			     u8 private_data_len)
2094 {
2095 	char *priv = NULL;
2096 	int i;
2097 
2098 	if (private_data_len && (priv = kmalloc(private_data_len * 3 + 1,
2099 						GFP_KERNEL))) {
2100 		for (i = 0; i < private_data_len; i++)
2101 			sprintf(priv + 3 * i, " %02x", private_data[i]);
2102 	}
2103 	pr_info("Received CM REJ for ch %s-%d; reason %d%s%s.\n",
2104 		ch->sess_name, ch->qp->qp_num, reason, private_data_len ?
2105 		"; private data" : "", priv ? priv : " (?)");
2106 	kfree(priv);
2107 }
2108 
2109 /**
2110  * srpt_cm_rtu_recv() - Process an IB_CM_RTU_RECEIVED or USER_ESTABLISHED event.
2111  *
2112  * An IB_CM_RTU_RECEIVED message indicates that the connection is established
2113  * and that the recipient may begin transmitting (RTU = ready to use).
2114  */
2115 static void srpt_cm_rtu_recv(struct srpt_rdma_ch *ch)
2116 {
2117 	int ret;
2118 
2119 	if (srpt_set_ch_state(ch, CH_LIVE)) {
2120 		ret = srpt_ch_qp_rts(ch, ch->qp);
2121 
2122 		if (ret == 0) {
2123 			/* Trigger wait list processing. */
2124 			ret = srpt_zerolength_write(ch);
2125 			WARN_ONCE(ret < 0, "%d\n", ret);
2126 		} else {
2127 			srpt_close_ch(ch);
2128 		}
2129 	}
2130 }
2131 
2132 /**
2133  * srpt_cm_handler() - IB connection manager callback function.
2134  *
2135  * A non-zero return value will cause the caller destroy the CM ID.
2136  *
2137  * Note: srpt_cm_handler() must only return a non-zero value when transferring
2138  * ownership of the cm_id to a channel by srpt_cm_req_recv() failed. Returning
2139  * a non-zero value in any other case will trigger a race with the
2140  * ib_destroy_cm_id() call in srpt_release_channel().
2141  */
2142 static int srpt_cm_handler(struct ib_cm_id *cm_id, struct ib_cm_event *event)
2143 {
2144 	struct srpt_rdma_ch *ch = cm_id->context;
2145 	int ret;
2146 
2147 	ret = 0;
2148 	switch (event->event) {
2149 	case IB_CM_REQ_RECEIVED:
2150 		ret = srpt_cm_req_recv(cm_id, &event->param.req_rcvd,
2151 				       event->private_data);
2152 		break;
2153 	case IB_CM_REJ_RECEIVED:
2154 		srpt_cm_rej_recv(ch, event->param.rej_rcvd.reason,
2155 				 event->private_data,
2156 				 IB_CM_REJ_PRIVATE_DATA_SIZE);
2157 		break;
2158 	case IB_CM_RTU_RECEIVED:
2159 	case IB_CM_USER_ESTABLISHED:
2160 		srpt_cm_rtu_recv(ch);
2161 		break;
2162 	case IB_CM_DREQ_RECEIVED:
2163 		srpt_disconnect_ch(ch);
2164 		break;
2165 	case IB_CM_DREP_RECEIVED:
2166 		pr_info("Received CM DREP message for ch %s-%d.\n",
2167 			ch->sess_name, ch->qp->qp_num);
2168 		srpt_close_ch(ch);
2169 		break;
2170 	case IB_CM_TIMEWAIT_EXIT:
2171 		pr_info("Received CM TimeWait exit for ch %s-%d.\n",
2172 			ch->sess_name, ch->qp->qp_num);
2173 		srpt_close_ch(ch);
2174 		break;
2175 	case IB_CM_REP_ERROR:
2176 		pr_info("Received CM REP error for ch %s-%d.\n", ch->sess_name,
2177 			ch->qp->qp_num);
2178 		break;
2179 	case IB_CM_DREQ_ERROR:
2180 		pr_info("Received CM DREQ ERROR event.\n");
2181 		break;
2182 	case IB_CM_MRA_RECEIVED:
2183 		pr_info("Received CM MRA event\n");
2184 		break;
2185 	default:
2186 		pr_err("received unrecognized CM event %d\n", event->event);
2187 		break;
2188 	}
2189 
2190 	return ret;
2191 }
2192 
2193 static int srpt_write_pending_status(struct se_cmd *se_cmd)
2194 {
2195 	struct srpt_send_ioctx *ioctx;
2196 
2197 	ioctx = container_of(se_cmd, struct srpt_send_ioctx, cmd);
2198 	return srpt_get_cmd_state(ioctx) == SRPT_STATE_NEED_DATA;
2199 }
2200 
2201 /*
2202  * srpt_write_pending() - Start data transfer from initiator to target (write).
2203  */
2204 static int srpt_write_pending(struct se_cmd *se_cmd)
2205 {
2206 	struct srpt_send_ioctx *ioctx =
2207 		container_of(se_cmd, struct srpt_send_ioctx, cmd);
2208 	struct srpt_rdma_ch *ch = ioctx->ch;
2209 	struct ib_send_wr *first_wr = NULL, *bad_wr;
2210 	struct ib_cqe *cqe = &ioctx->rdma_cqe;
2211 	enum srpt_command_state new_state;
2212 	int ret, i;
2213 
2214 	new_state = srpt_set_cmd_state(ioctx, SRPT_STATE_NEED_DATA);
2215 	WARN_ON(new_state == SRPT_STATE_DONE);
2216 
2217 	if (atomic_sub_return(ioctx->n_rdma, &ch->sq_wr_avail) < 0) {
2218 		pr_warn("%s: IB send queue full (needed %d)\n",
2219 				__func__, ioctx->n_rdma);
2220 		ret = -ENOMEM;
2221 		goto out_undo;
2222 	}
2223 
2224 	cqe->done = srpt_rdma_read_done;
2225 	for (i = ioctx->n_rw_ctx - 1; i >= 0; i--) {
2226 		struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
2227 
2228 		first_wr = rdma_rw_ctx_wrs(&ctx->rw, ch->qp, ch->sport->port,
2229 				cqe, first_wr);
2230 		cqe = NULL;
2231 	}
2232 
2233 	ret = ib_post_send(ch->qp, first_wr, &bad_wr);
2234 	if (ret) {
2235 		pr_err("%s: ib_post_send() returned %d for %d (avail: %d)\n",
2236 			 __func__, ret, ioctx->n_rdma,
2237 			 atomic_read(&ch->sq_wr_avail));
2238 		goto out_undo;
2239 	}
2240 
2241 	return 0;
2242 out_undo:
2243 	atomic_add(ioctx->n_rdma, &ch->sq_wr_avail);
2244 	return ret;
2245 }
2246 
2247 static u8 tcm_to_srp_tsk_mgmt_status(const int tcm_mgmt_status)
2248 {
2249 	switch (tcm_mgmt_status) {
2250 	case TMR_FUNCTION_COMPLETE:
2251 		return SRP_TSK_MGMT_SUCCESS;
2252 	case TMR_FUNCTION_REJECTED:
2253 		return SRP_TSK_MGMT_FUNC_NOT_SUPP;
2254 	}
2255 	return SRP_TSK_MGMT_FAILED;
2256 }
2257 
2258 /**
2259  * srpt_queue_response() - Transmits the response to a SCSI command.
2260  *
2261  * Callback function called by the TCM core. Must not block since it can be
2262  * invoked on the context of the IB completion handler.
2263  */
2264 static void srpt_queue_response(struct se_cmd *cmd)
2265 {
2266 	struct srpt_send_ioctx *ioctx =
2267 		container_of(cmd, struct srpt_send_ioctx, cmd);
2268 	struct srpt_rdma_ch *ch = ioctx->ch;
2269 	struct srpt_device *sdev = ch->sport->sdev;
2270 	struct ib_send_wr send_wr, *first_wr = &send_wr, *bad_wr;
2271 	struct ib_sge sge;
2272 	enum srpt_command_state state;
2273 	unsigned long flags;
2274 	int resp_len, ret, i;
2275 	u8 srp_tm_status;
2276 
2277 	BUG_ON(!ch);
2278 
2279 	spin_lock_irqsave(&ioctx->spinlock, flags);
2280 	state = ioctx->state;
2281 	switch (state) {
2282 	case SRPT_STATE_NEW:
2283 	case SRPT_STATE_DATA_IN:
2284 		ioctx->state = SRPT_STATE_CMD_RSP_SENT;
2285 		break;
2286 	case SRPT_STATE_MGMT:
2287 		ioctx->state = SRPT_STATE_MGMT_RSP_SENT;
2288 		break;
2289 	default:
2290 		WARN(true, "ch %p; cmd %d: unexpected command state %d\n",
2291 			ch, ioctx->ioctx.index, ioctx->state);
2292 		break;
2293 	}
2294 	spin_unlock_irqrestore(&ioctx->spinlock, flags);
2295 
2296 	if (unlikely(transport_check_aborted_status(&ioctx->cmd, false)
2297 		     || WARN_ON_ONCE(state == SRPT_STATE_CMD_RSP_SENT))) {
2298 		atomic_inc(&ch->req_lim_delta);
2299 		srpt_abort_cmd(ioctx);
2300 		return;
2301 	}
2302 
2303 	/* For read commands, transfer the data to the initiator. */
2304 	if (ioctx->cmd.data_direction == DMA_FROM_DEVICE &&
2305 	    ioctx->cmd.data_length &&
2306 	    !ioctx->queue_status_only) {
2307 		for (i = ioctx->n_rw_ctx - 1; i >= 0; i--) {
2308 			struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
2309 
2310 			first_wr = rdma_rw_ctx_wrs(&ctx->rw, ch->qp,
2311 					ch->sport->port, NULL, first_wr);
2312 		}
2313 	}
2314 
2315 	if (state != SRPT_STATE_MGMT)
2316 		resp_len = srpt_build_cmd_rsp(ch, ioctx, ioctx->cmd.tag,
2317 					      cmd->scsi_status);
2318 	else {
2319 		srp_tm_status
2320 			= tcm_to_srp_tsk_mgmt_status(cmd->se_tmr_req->response);
2321 		resp_len = srpt_build_tskmgmt_rsp(ch, ioctx, srp_tm_status,
2322 						 ioctx->cmd.tag);
2323 	}
2324 
2325 	atomic_inc(&ch->req_lim);
2326 
2327 	if (unlikely(atomic_sub_return(1 + ioctx->n_rdma,
2328 			&ch->sq_wr_avail) < 0)) {
2329 		pr_warn("%s: IB send queue full (needed %d)\n",
2330 				__func__, ioctx->n_rdma);
2331 		ret = -ENOMEM;
2332 		goto out;
2333 	}
2334 
2335 	ib_dma_sync_single_for_device(sdev->device, ioctx->ioctx.dma, resp_len,
2336 				      DMA_TO_DEVICE);
2337 
2338 	sge.addr = ioctx->ioctx.dma;
2339 	sge.length = resp_len;
2340 	sge.lkey = sdev->pd->local_dma_lkey;
2341 
2342 	ioctx->ioctx.cqe.done = srpt_send_done;
2343 	send_wr.next = NULL;
2344 	send_wr.wr_cqe = &ioctx->ioctx.cqe;
2345 	send_wr.sg_list = &sge;
2346 	send_wr.num_sge = 1;
2347 	send_wr.opcode = IB_WR_SEND;
2348 	send_wr.send_flags = IB_SEND_SIGNALED;
2349 
2350 	ret = ib_post_send(ch->qp, first_wr, &bad_wr);
2351 	if (ret < 0) {
2352 		pr_err("%s: sending cmd response failed for tag %llu (%d)\n",
2353 			__func__, ioctx->cmd.tag, ret);
2354 		goto out;
2355 	}
2356 
2357 	return;
2358 
2359 out:
2360 	atomic_add(1 + ioctx->n_rdma, &ch->sq_wr_avail);
2361 	atomic_dec(&ch->req_lim);
2362 	srpt_set_cmd_state(ioctx, SRPT_STATE_DONE);
2363 	target_put_sess_cmd(&ioctx->cmd);
2364 }
2365 
2366 static int srpt_queue_data_in(struct se_cmd *cmd)
2367 {
2368 	srpt_queue_response(cmd);
2369 	return 0;
2370 }
2371 
2372 static void srpt_queue_tm_rsp(struct se_cmd *cmd)
2373 {
2374 	srpt_queue_response(cmd);
2375 }
2376 
2377 static void srpt_aborted_task(struct se_cmd *cmd)
2378 {
2379 }
2380 
2381 static int srpt_queue_status(struct se_cmd *cmd)
2382 {
2383 	struct srpt_send_ioctx *ioctx;
2384 
2385 	ioctx = container_of(cmd, struct srpt_send_ioctx, cmd);
2386 	BUG_ON(ioctx->sense_data != cmd->sense_buffer);
2387 	if (cmd->se_cmd_flags &
2388 	    (SCF_TRANSPORT_TASK_SENSE | SCF_EMULATED_TASK_SENSE))
2389 		WARN_ON(cmd->scsi_status != SAM_STAT_CHECK_CONDITION);
2390 	ioctx->queue_status_only = true;
2391 	srpt_queue_response(cmd);
2392 	return 0;
2393 }
2394 
2395 static void srpt_refresh_port_work(struct work_struct *work)
2396 {
2397 	struct srpt_port *sport = container_of(work, struct srpt_port, work);
2398 
2399 	srpt_refresh_port(sport);
2400 }
2401 
2402 /**
2403  * srpt_release_sdev() - Free the channel resources associated with a target.
2404  */
2405 static int srpt_release_sdev(struct srpt_device *sdev)
2406 {
2407 	int i, res;
2408 
2409 	WARN_ON_ONCE(irqs_disabled());
2410 
2411 	BUG_ON(!sdev);
2412 
2413 	mutex_lock(&sdev->mutex);
2414 	for (i = 0; i < ARRAY_SIZE(sdev->port); i++)
2415 		sdev->port[i].enabled = false;
2416 	__srpt_close_all_ch(sdev);
2417 	mutex_unlock(&sdev->mutex);
2418 
2419 	res = wait_event_interruptible(sdev->ch_releaseQ,
2420 				       list_empty_careful(&sdev->rch_list));
2421 	if (res)
2422 		pr_err("%s: interrupted.\n", __func__);
2423 
2424 	return 0;
2425 }
2426 
2427 static struct srpt_port *__srpt_lookup_port(const char *name)
2428 {
2429 	struct ib_device *dev;
2430 	struct srpt_device *sdev;
2431 	struct srpt_port *sport;
2432 	int i;
2433 
2434 	list_for_each_entry(sdev, &srpt_dev_list, list) {
2435 		dev = sdev->device;
2436 		if (!dev)
2437 			continue;
2438 
2439 		for (i = 0; i < dev->phys_port_cnt; i++) {
2440 			sport = &sdev->port[i];
2441 
2442 			if (!strcmp(sport->port_guid, name))
2443 				return sport;
2444 		}
2445 	}
2446 
2447 	return NULL;
2448 }
2449 
2450 static struct srpt_port *srpt_lookup_port(const char *name)
2451 {
2452 	struct srpt_port *sport;
2453 
2454 	spin_lock(&srpt_dev_lock);
2455 	sport = __srpt_lookup_port(name);
2456 	spin_unlock(&srpt_dev_lock);
2457 
2458 	return sport;
2459 }
2460 
2461 /**
2462  * srpt_add_one() - Infiniband device addition callback function.
2463  */
2464 static void srpt_add_one(struct ib_device *device)
2465 {
2466 	struct srpt_device *sdev;
2467 	struct srpt_port *sport;
2468 	struct ib_srq_init_attr srq_attr;
2469 	int i;
2470 
2471 	pr_debug("device = %p, device->dma_ops = %p\n", device,
2472 		 device->dma_ops);
2473 
2474 	sdev = kzalloc(sizeof(*sdev), GFP_KERNEL);
2475 	if (!sdev)
2476 		goto err;
2477 
2478 	sdev->device = device;
2479 	INIT_LIST_HEAD(&sdev->rch_list);
2480 	init_waitqueue_head(&sdev->ch_releaseQ);
2481 	mutex_init(&sdev->mutex);
2482 
2483 	sdev->pd = ib_alloc_pd(device, 0);
2484 	if (IS_ERR(sdev->pd))
2485 		goto free_dev;
2486 
2487 	sdev->srq_size = min(srpt_srq_size, sdev->device->attrs.max_srq_wr);
2488 
2489 	srq_attr.event_handler = srpt_srq_event;
2490 	srq_attr.srq_context = (void *)sdev;
2491 	srq_attr.attr.max_wr = sdev->srq_size;
2492 	srq_attr.attr.max_sge = 1;
2493 	srq_attr.attr.srq_limit = 0;
2494 	srq_attr.srq_type = IB_SRQT_BASIC;
2495 
2496 	sdev->srq = ib_create_srq(sdev->pd, &srq_attr);
2497 	if (IS_ERR(sdev->srq))
2498 		goto err_pd;
2499 
2500 	pr_debug("%s: create SRQ #wr= %d max_allow=%d dev= %s\n",
2501 		 __func__, sdev->srq_size, sdev->device->attrs.max_srq_wr,
2502 		 device->name);
2503 
2504 	if (!srpt_service_guid)
2505 		srpt_service_guid = be64_to_cpu(device->node_guid);
2506 
2507 	sdev->cm_id = ib_create_cm_id(device, srpt_cm_handler, sdev);
2508 	if (IS_ERR(sdev->cm_id))
2509 		goto err_srq;
2510 
2511 	/* print out target login information */
2512 	pr_debug("Target login info: id_ext=%016llx,ioc_guid=%016llx,"
2513 		 "pkey=ffff,service_id=%016llx\n", srpt_service_guid,
2514 		 srpt_service_guid, srpt_service_guid);
2515 
2516 	/*
2517 	 * We do not have a consistent service_id (ie. also id_ext of target_id)
2518 	 * to identify this target. We currently use the guid of the first HCA
2519 	 * in the system as service_id; therefore, the target_id will change
2520 	 * if this HCA is gone bad and replaced by different HCA
2521 	 */
2522 	if (ib_cm_listen(sdev->cm_id, cpu_to_be64(srpt_service_guid), 0))
2523 		goto err_cm;
2524 
2525 	INIT_IB_EVENT_HANDLER(&sdev->event_handler, sdev->device,
2526 			      srpt_event_handler);
2527 	if (ib_register_event_handler(&sdev->event_handler))
2528 		goto err_cm;
2529 
2530 	sdev->ioctx_ring = (struct srpt_recv_ioctx **)
2531 		srpt_alloc_ioctx_ring(sdev, sdev->srq_size,
2532 				      sizeof(*sdev->ioctx_ring[0]),
2533 				      srp_max_req_size, DMA_FROM_DEVICE);
2534 	if (!sdev->ioctx_ring)
2535 		goto err_event;
2536 
2537 	for (i = 0; i < sdev->srq_size; ++i)
2538 		srpt_post_recv(sdev, sdev->ioctx_ring[i]);
2539 
2540 	WARN_ON(sdev->device->phys_port_cnt > ARRAY_SIZE(sdev->port));
2541 
2542 	for (i = 1; i <= sdev->device->phys_port_cnt; i++) {
2543 		sport = &sdev->port[i - 1];
2544 		sport->sdev = sdev;
2545 		sport->port = i;
2546 		sport->port_attrib.srp_max_rdma_size = DEFAULT_MAX_RDMA_SIZE;
2547 		sport->port_attrib.srp_max_rsp_size = DEFAULT_MAX_RSP_SIZE;
2548 		sport->port_attrib.srp_sq_size = DEF_SRPT_SQ_SIZE;
2549 		INIT_WORK(&sport->work, srpt_refresh_port_work);
2550 
2551 		if (srpt_refresh_port(sport)) {
2552 			pr_err("MAD registration failed for %s-%d.\n",
2553 			       sdev->device->name, i);
2554 			goto err_ring;
2555 		}
2556 	}
2557 
2558 	spin_lock(&srpt_dev_lock);
2559 	list_add_tail(&sdev->list, &srpt_dev_list);
2560 	spin_unlock(&srpt_dev_lock);
2561 
2562 out:
2563 	ib_set_client_data(device, &srpt_client, sdev);
2564 	pr_debug("added %s.\n", device->name);
2565 	return;
2566 
2567 err_ring:
2568 	srpt_free_ioctx_ring((struct srpt_ioctx **)sdev->ioctx_ring, sdev,
2569 			     sdev->srq_size, srp_max_req_size,
2570 			     DMA_FROM_DEVICE);
2571 err_event:
2572 	ib_unregister_event_handler(&sdev->event_handler);
2573 err_cm:
2574 	ib_destroy_cm_id(sdev->cm_id);
2575 err_srq:
2576 	ib_destroy_srq(sdev->srq);
2577 err_pd:
2578 	ib_dealloc_pd(sdev->pd);
2579 free_dev:
2580 	kfree(sdev);
2581 err:
2582 	sdev = NULL;
2583 	pr_info("%s(%s) failed.\n", __func__, device->name);
2584 	goto out;
2585 }
2586 
2587 /**
2588  * srpt_remove_one() - InfiniBand device removal callback function.
2589  */
2590 static void srpt_remove_one(struct ib_device *device, void *client_data)
2591 {
2592 	struct srpt_device *sdev = client_data;
2593 	int i;
2594 
2595 	if (!sdev) {
2596 		pr_info("%s(%s): nothing to do.\n", __func__, device->name);
2597 		return;
2598 	}
2599 
2600 	srpt_unregister_mad_agent(sdev);
2601 
2602 	ib_unregister_event_handler(&sdev->event_handler);
2603 
2604 	/* Cancel any work queued by the just unregistered IB event handler. */
2605 	for (i = 0; i < sdev->device->phys_port_cnt; i++)
2606 		cancel_work_sync(&sdev->port[i].work);
2607 
2608 	ib_destroy_cm_id(sdev->cm_id);
2609 
2610 	/*
2611 	 * Unregistering a target must happen after destroying sdev->cm_id
2612 	 * such that no new SRP_LOGIN_REQ information units can arrive while
2613 	 * destroying the target.
2614 	 */
2615 	spin_lock(&srpt_dev_lock);
2616 	list_del(&sdev->list);
2617 	spin_unlock(&srpt_dev_lock);
2618 	srpt_release_sdev(sdev);
2619 
2620 	ib_destroy_srq(sdev->srq);
2621 	ib_dealloc_pd(sdev->pd);
2622 
2623 	srpt_free_ioctx_ring((struct srpt_ioctx **)sdev->ioctx_ring, sdev,
2624 			     sdev->srq_size, srp_max_req_size, DMA_FROM_DEVICE);
2625 	sdev->ioctx_ring = NULL;
2626 	kfree(sdev);
2627 }
2628 
2629 static struct ib_client srpt_client = {
2630 	.name = DRV_NAME,
2631 	.add = srpt_add_one,
2632 	.remove = srpt_remove_one
2633 };
2634 
2635 static int srpt_check_true(struct se_portal_group *se_tpg)
2636 {
2637 	return 1;
2638 }
2639 
2640 static int srpt_check_false(struct se_portal_group *se_tpg)
2641 {
2642 	return 0;
2643 }
2644 
2645 static char *srpt_get_fabric_name(void)
2646 {
2647 	return "srpt";
2648 }
2649 
2650 static char *srpt_get_fabric_wwn(struct se_portal_group *tpg)
2651 {
2652 	struct srpt_port *sport = container_of(tpg, struct srpt_port, port_tpg_1);
2653 
2654 	return sport->port_guid;
2655 }
2656 
2657 static u16 srpt_get_tag(struct se_portal_group *tpg)
2658 {
2659 	return 1;
2660 }
2661 
2662 static u32 srpt_tpg_get_inst_index(struct se_portal_group *se_tpg)
2663 {
2664 	return 1;
2665 }
2666 
2667 static void srpt_release_cmd(struct se_cmd *se_cmd)
2668 {
2669 	struct srpt_send_ioctx *ioctx = container_of(se_cmd,
2670 				struct srpt_send_ioctx, cmd);
2671 	struct srpt_rdma_ch *ch = ioctx->ch;
2672 	unsigned long flags;
2673 
2674 	WARN_ON(ioctx->state != SRPT_STATE_DONE);
2675 
2676 	if (ioctx->n_rw_ctx) {
2677 		srpt_free_rw_ctxs(ch, ioctx);
2678 		ioctx->n_rw_ctx = 0;
2679 	}
2680 
2681 	spin_lock_irqsave(&ch->spinlock, flags);
2682 	list_add(&ioctx->free_list, &ch->free_list);
2683 	spin_unlock_irqrestore(&ch->spinlock, flags);
2684 }
2685 
2686 /**
2687  * srpt_close_session() - Forcibly close a session.
2688  *
2689  * Callback function invoked by the TCM core to clean up sessions associated
2690  * with a node ACL when the user invokes
2691  * rmdir /sys/kernel/config/target/$driver/$port/$tpg/acls/$i_port_id
2692  */
2693 static void srpt_close_session(struct se_session *se_sess)
2694 {
2695 	DECLARE_COMPLETION_ONSTACK(release_done);
2696 	struct srpt_rdma_ch *ch = se_sess->fabric_sess_ptr;
2697 	struct srpt_device *sdev = ch->sport->sdev;
2698 	bool wait;
2699 
2700 	pr_debug("ch %s-%d state %d\n", ch->sess_name, ch->qp->qp_num,
2701 		 ch->state);
2702 
2703 	mutex_lock(&sdev->mutex);
2704 	BUG_ON(ch->release_done);
2705 	ch->release_done = &release_done;
2706 	wait = !list_empty(&ch->list);
2707 	srpt_disconnect_ch(ch);
2708 	mutex_unlock(&sdev->mutex);
2709 
2710 	if (!wait)
2711 		return;
2712 
2713 	while (wait_for_completion_timeout(&release_done, 180 * HZ) == 0)
2714 		pr_info("%s(%s-%d state %d): still waiting ...\n", __func__,
2715 			ch->sess_name, ch->qp->qp_num, ch->state);
2716 }
2717 
2718 /**
2719  * srpt_sess_get_index() - Return the value of scsiAttIntrPortIndex (SCSI-MIB).
2720  *
2721  * A quote from RFC 4455 (SCSI-MIB) about this MIB object:
2722  * This object represents an arbitrary integer used to uniquely identify a
2723  * particular attached remote initiator port to a particular SCSI target port
2724  * within a particular SCSI target device within a particular SCSI instance.
2725  */
2726 static u32 srpt_sess_get_index(struct se_session *se_sess)
2727 {
2728 	return 0;
2729 }
2730 
2731 static void srpt_set_default_node_attrs(struct se_node_acl *nacl)
2732 {
2733 }
2734 
2735 /* Note: only used from inside debug printk's by the TCM core. */
2736 static int srpt_get_tcm_cmd_state(struct se_cmd *se_cmd)
2737 {
2738 	struct srpt_send_ioctx *ioctx;
2739 
2740 	ioctx = container_of(se_cmd, struct srpt_send_ioctx, cmd);
2741 	return srpt_get_cmd_state(ioctx);
2742 }
2743 
2744 /**
2745  * srpt_parse_i_port_id() - Parse an initiator port ID.
2746  * @name: ASCII representation of a 128-bit initiator port ID.
2747  * @i_port_id: Binary 128-bit port ID.
2748  */
2749 static int srpt_parse_i_port_id(u8 i_port_id[16], const char *name)
2750 {
2751 	const char *p;
2752 	unsigned len, count, leading_zero_bytes;
2753 	int ret, rc;
2754 
2755 	p = name;
2756 	if (strncasecmp(p, "0x", 2) == 0)
2757 		p += 2;
2758 	ret = -EINVAL;
2759 	len = strlen(p);
2760 	if (len % 2)
2761 		goto out;
2762 	count = min(len / 2, 16U);
2763 	leading_zero_bytes = 16 - count;
2764 	memset(i_port_id, 0, leading_zero_bytes);
2765 	rc = hex2bin(i_port_id + leading_zero_bytes, p, count);
2766 	if (rc < 0)
2767 		pr_debug("hex2bin failed for srpt_parse_i_port_id: %d\n", rc);
2768 	ret = 0;
2769 out:
2770 	return ret;
2771 }
2772 
2773 /*
2774  * configfs callback function invoked for
2775  * mkdir /sys/kernel/config/target/$driver/$port/$tpg/acls/$i_port_id
2776  */
2777 static int srpt_init_nodeacl(struct se_node_acl *se_nacl, const char *name)
2778 {
2779 	u8 i_port_id[16];
2780 
2781 	if (srpt_parse_i_port_id(i_port_id, name) < 0) {
2782 		pr_err("invalid initiator port ID %s\n", name);
2783 		return -EINVAL;
2784 	}
2785 	return 0;
2786 }
2787 
2788 static ssize_t srpt_tpg_attrib_srp_max_rdma_size_show(struct config_item *item,
2789 		char *page)
2790 {
2791 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
2792 	struct srpt_port *sport = container_of(se_tpg, struct srpt_port, port_tpg_1);
2793 
2794 	return sprintf(page, "%u\n", sport->port_attrib.srp_max_rdma_size);
2795 }
2796 
2797 static ssize_t srpt_tpg_attrib_srp_max_rdma_size_store(struct config_item *item,
2798 		const char *page, size_t count)
2799 {
2800 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
2801 	struct srpt_port *sport = container_of(se_tpg, struct srpt_port, port_tpg_1);
2802 	unsigned long val;
2803 	int ret;
2804 
2805 	ret = kstrtoul(page, 0, &val);
2806 	if (ret < 0) {
2807 		pr_err("kstrtoul() failed with ret: %d\n", ret);
2808 		return -EINVAL;
2809 	}
2810 	if (val > MAX_SRPT_RDMA_SIZE) {
2811 		pr_err("val: %lu exceeds MAX_SRPT_RDMA_SIZE: %d\n", val,
2812 			MAX_SRPT_RDMA_SIZE);
2813 		return -EINVAL;
2814 	}
2815 	if (val < DEFAULT_MAX_RDMA_SIZE) {
2816 		pr_err("val: %lu smaller than DEFAULT_MAX_RDMA_SIZE: %d\n",
2817 			val, DEFAULT_MAX_RDMA_SIZE);
2818 		return -EINVAL;
2819 	}
2820 	sport->port_attrib.srp_max_rdma_size = val;
2821 
2822 	return count;
2823 }
2824 
2825 static ssize_t srpt_tpg_attrib_srp_max_rsp_size_show(struct config_item *item,
2826 		char *page)
2827 {
2828 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
2829 	struct srpt_port *sport = container_of(se_tpg, struct srpt_port, port_tpg_1);
2830 
2831 	return sprintf(page, "%u\n", sport->port_attrib.srp_max_rsp_size);
2832 }
2833 
2834 static ssize_t srpt_tpg_attrib_srp_max_rsp_size_store(struct config_item *item,
2835 		const char *page, size_t count)
2836 {
2837 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
2838 	struct srpt_port *sport = container_of(se_tpg, struct srpt_port, port_tpg_1);
2839 	unsigned long val;
2840 	int ret;
2841 
2842 	ret = kstrtoul(page, 0, &val);
2843 	if (ret < 0) {
2844 		pr_err("kstrtoul() failed with ret: %d\n", ret);
2845 		return -EINVAL;
2846 	}
2847 	if (val > MAX_SRPT_RSP_SIZE) {
2848 		pr_err("val: %lu exceeds MAX_SRPT_RSP_SIZE: %d\n", val,
2849 			MAX_SRPT_RSP_SIZE);
2850 		return -EINVAL;
2851 	}
2852 	if (val < MIN_MAX_RSP_SIZE) {
2853 		pr_err("val: %lu smaller than MIN_MAX_RSP_SIZE: %d\n", val,
2854 			MIN_MAX_RSP_SIZE);
2855 		return -EINVAL;
2856 	}
2857 	sport->port_attrib.srp_max_rsp_size = val;
2858 
2859 	return count;
2860 }
2861 
2862 static ssize_t srpt_tpg_attrib_srp_sq_size_show(struct config_item *item,
2863 		char *page)
2864 {
2865 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
2866 	struct srpt_port *sport = container_of(se_tpg, struct srpt_port, port_tpg_1);
2867 
2868 	return sprintf(page, "%u\n", sport->port_attrib.srp_sq_size);
2869 }
2870 
2871 static ssize_t srpt_tpg_attrib_srp_sq_size_store(struct config_item *item,
2872 		const char *page, size_t count)
2873 {
2874 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
2875 	struct srpt_port *sport = container_of(se_tpg, struct srpt_port, port_tpg_1);
2876 	unsigned long val;
2877 	int ret;
2878 
2879 	ret = kstrtoul(page, 0, &val);
2880 	if (ret < 0) {
2881 		pr_err("kstrtoul() failed with ret: %d\n", ret);
2882 		return -EINVAL;
2883 	}
2884 	if (val > MAX_SRPT_SRQ_SIZE) {
2885 		pr_err("val: %lu exceeds MAX_SRPT_SRQ_SIZE: %d\n", val,
2886 			MAX_SRPT_SRQ_SIZE);
2887 		return -EINVAL;
2888 	}
2889 	if (val < MIN_SRPT_SRQ_SIZE) {
2890 		pr_err("val: %lu smaller than MIN_SRPT_SRQ_SIZE: %d\n", val,
2891 			MIN_SRPT_SRQ_SIZE);
2892 		return -EINVAL;
2893 	}
2894 	sport->port_attrib.srp_sq_size = val;
2895 
2896 	return count;
2897 }
2898 
2899 CONFIGFS_ATTR(srpt_tpg_attrib_,  srp_max_rdma_size);
2900 CONFIGFS_ATTR(srpt_tpg_attrib_,  srp_max_rsp_size);
2901 CONFIGFS_ATTR(srpt_tpg_attrib_,  srp_sq_size);
2902 
2903 static struct configfs_attribute *srpt_tpg_attrib_attrs[] = {
2904 	&srpt_tpg_attrib_attr_srp_max_rdma_size,
2905 	&srpt_tpg_attrib_attr_srp_max_rsp_size,
2906 	&srpt_tpg_attrib_attr_srp_sq_size,
2907 	NULL,
2908 };
2909 
2910 static ssize_t srpt_tpg_enable_show(struct config_item *item, char *page)
2911 {
2912 	struct se_portal_group *se_tpg = to_tpg(item);
2913 	struct srpt_port *sport = container_of(se_tpg, struct srpt_port, port_tpg_1);
2914 
2915 	return snprintf(page, PAGE_SIZE, "%d\n", (sport->enabled) ? 1: 0);
2916 }
2917 
2918 static ssize_t srpt_tpg_enable_store(struct config_item *item,
2919 		const char *page, size_t count)
2920 {
2921 	struct se_portal_group *se_tpg = to_tpg(item);
2922 	struct srpt_port *sport = container_of(se_tpg, struct srpt_port, port_tpg_1);
2923 	struct srpt_device *sdev = sport->sdev;
2924 	struct srpt_rdma_ch *ch;
2925 	unsigned long tmp;
2926         int ret;
2927 
2928 	ret = kstrtoul(page, 0, &tmp);
2929 	if (ret < 0) {
2930 		pr_err("Unable to extract srpt_tpg_store_enable\n");
2931 		return -EINVAL;
2932 	}
2933 
2934 	if ((tmp != 0) && (tmp != 1)) {
2935 		pr_err("Illegal value for srpt_tpg_store_enable: %lu\n", tmp);
2936 		return -EINVAL;
2937 	}
2938 	if (sport->enabled == tmp)
2939 		goto out;
2940 	sport->enabled = tmp;
2941 	if (sport->enabled)
2942 		goto out;
2943 
2944 	mutex_lock(&sdev->mutex);
2945 	list_for_each_entry(ch, &sdev->rch_list, list) {
2946 		if (ch->sport == sport) {
2947 			pr_debug("%s: ch %p %s-%d\n", __func__, ch,
2948 				 ch->sess_name, ch->qp->qp_num);
2949 			srpt_disconnect_ch(ch);
2950 			srpt_close_ch(ch);
2951 		}
2952 	}
2953 	mutex_unlock(&sdev->mutex);
2954 
2955 out:
2956 	return count;
2957 }
2958 
2959 CONFIGFS_ATTR(srpt_tpg_, enable);
2960 
2961 static struct configfs_attribute *srpt_tpg_attrs[] = {
2962 	&srpt_tpg_attr_enable,
2963 	NULL,
2964 };
2965 
2966 /**
2967  * configfs callback invoked for
2968  * mkdir /sys/kernel/config/target/$driver/$port/$tpg
2969  */
2970 static struct se_portal_group *srpt_make_tpg(struct se_wwn *wwn,
2971 					     struct config_group *group,
2972 					     const char *name)
2973 {
2974 	struct srpt_port *sport = container_of(wwn, struct srpt_port, port_wwn);
2975 	int res;
2976 
2977 	/* Initialize sport->port_wwn and sport->port_tpg_1 */
2978 	res = core_tpg_register(&sport->port_wwn, &sport->port_tpg_1, SCSI_PROTOCOL_SRP);
2979 	if (res)
2980 		return ERR_PTR(res);
2981 
2982 	return &sport->port_tpg_1;
2983 }
2984 
2985 /**
2986  * configfs callback invoked for
2987  * rmdir /sys/kernel/config/target/$driver/$port/$tpg
2988  */
2989 static void srpt_drop_tpg(struct se_portal_group *tpg)
2990 {
2991 	struct srpt_port *sport = container_of(tpg,
2992 				struct srpt_port, port_tpg_1);
2993 
2994 	sport->enabled = false;
2995 	core_tpg_deregister(&sport->port_tpg_1);
2996 }
2997 
2998 /**
2999  * configfs callback invoked for
3000  * mkdir /sys/kernel/config/target/$driver/$port
3001  */
3002 static struct se_wwn *srpt_make_tport(struct target_fabric_configfs *tf,
3003 				      struct config_group *group,
3004 				      const char *name)
3005 {
3006 	struct srpt_port *sport;
3007 	int ret;
3008 
3009 	sport = srpt_lookup_port(name);
3010 	pr_debug("make_tport(%s)\n", name);
3011 	ret = -EINVAL;
3012 	if (!sport)
3013 		goto err;
3014 
3015 	return &sport->port_wwn;
3016 
3017 err:
3018 	return ERR_PTR(ret);
3019 }
3020 
3021 /**
3022  * configfs callback invoked for
3023  * rmdir /sys/kernel/config/target/$driver/$port
3024  */
3025 static void srpt_drop_tport(struct se_wwn *wwn)
3026 {
3027 	struct srpt_port *sport = container_of(wwn, struct srpt_port, port_wwn);
3028 
3029 	pr_debug("drop_tport(%s\n", config_item_name(&sport->port_wwn.wwn_group.cg_item));
3030 }
3031 
3032 static ssize_t srpt_wwn_version_show(struct config_item *item, char *buf)
3033 {
3034 	return scnprintf(buf, PAGE_SIZE, "%s\n", DRV_VERSION);
3035 }
3036 
3037 CONFIGFS_ATTR_RO(srpt_wwn_, version);
3038 
3039 static struct configfs_attribute *srpt_wwn_attrs[] = {
3040 	&srpt_wwn_attr_version,
3041 	NULL,
3042 };
3043 
3044 static const struct target_core_fabric_ops srpt_template = {
3045 	.module				= THIS_MODULE,
3046 	.name				= "srpt",
3047 	.get_fabric_name		= srpt_get_fabric_name,
3048 	.tpg_get_wwn			= srpt_get_fabric_wwn,
3049 	.tpg_get_tag			= srpt_get_tag,
3050 	.tpg_check_demo_mode		= srpt_check_false,
3051 	.tpg_check_demo_mode_cache	= srpt_check_true,
3052 	.tpg_check_demo_mode_write_protect = srpt_check_true,
3053 	.tpg_check_prod_mode_write_protect = srpt_check_false,
3054 	.tpg_get_inst_index		= srpt_tpg_get_inst_index,
3055 	.release_cmd			= srpt_release_cmd,
3056 	.check_stop_free		= srpt_check_stop_free,
3057 	.close_session			= srpt_close_session,
3058 	.sess_get_index			= srpt_sess_get_index,
3059 	.sess_get_initiator_sid		= NULL,
3060 	.write_pending			= srpt_write_pending,
3061 	.write_pending_status		= srpt_write_pending_status,
3062 	.set_default_node_attributes	= srpt_set_default_node_attrs,
3063 	.get_cmd_state			= srpt_get_tcm_cmd_state,
3064 	.queue_data_in			= srpt_queue_data_in,
3065 	.queue_status			= srpt_queue_status,
3066 	.queue_tm_rsp			= srpt_queue_tm_rsp,
3067 	.aborted_task			= srpt_aborted_task,
3068 	/*
3069 	 * Setup function pointers for generic logic in
3070 	 * target_core_fabric_configfs.c
3071 	 */
3072 	.fabric_make_wwn		= srpt_make_tport,
3073 	.fabric_drop_wwn		= srpt_drop_tport,
3074 	.fabric_make_tpg		= srpt_make_tpg,
3075 	.fabric_drop_tpg		= srpt_drop_tpg,
3076 	.fabric_init_nodeacl		= srpt_init_nodeacl,
3077 
3078 	.tfc_wwn_attrs			= srpt_wwn_attrs,
3079 	.tfc_tpg_base_attrs		= srpt_tpg_attrs,
3080 	.tfc_tpg_attrib_attrs		= srpt_tpg_attrib_attrs,
3081 };
3082 
3083 /**
3084  * srpt_init_module() - Kernel module initialization.
3085  *
3086  * Note: Since ib_register_client() registers callback functions, and since at
3087  * least one of these callback functions (srpt_add_one()) calls target core
3088  * functions, this driver must be registered with the target core before
3089  * ib_register_client() is called.
3090  */
3091 static int __init srpt_init_module(void)
3092 {
3093 	int ret;
3094 
3095 	ret = -EINVAL;
3096 	if (srp_max_req_size < MIN_MAX_REQ_SIZE) {
3097 		pr_err("invalid value %d for kernel module parameter"
3098 		       " srp_max_req_size -- must be at least %d.\n",
3099 		       srp_max_req_size, MIN_MAX_REQ_SIZE);
3100 		goto out;
3101 	}
3102 
3103 	if (srpt_srq_size < MIN_SRPT_SRQ_SIZE
3104 	    || srpt_srq_size > MAX_SRPT_SRQ_SIZE) {
3105 		pr_err("invalid value %d for kernel module parameter"
3106 		       " srpt_srq_size -- must be in the range [%d..%d].\n",
3107 		       srpt_srq_size, MIN_SRPT_SRQ_SIZE, MAX_SRPT_SRQ_SIZE);
3108 		goto out;
3109 	}
3110 
3111 	ret = target_register_template(&srpt_template);
3112 	if (ret)
3113 		goto out;
3114 
3115 	ret = ib_register_client(&srpt_client);
3116 	if (ret) {
3117 		pr_err("couldn't register IB client\n");
3118 		goto out_unregister_target;
3119 	}
3120 
3121 	return 0;
3122 
3123 out_unregister_target:
3124 	target_unregister_template(&srpt_template);
3125 out:
3126 	return ret;
3127 }
3128 
3129 static void __exit srpt_cleanup_module(void)
3130 {
3131 	ib_unregister_client(&srpt_client);
3132 	target_unregister_template(&srpt_template);
3133 }
3134 
3135 module_init(srpt_init_module);
3136 module_exit(srpt_cleanup_module);
3137