xref: /linux/drivers/infiniband/ulp/srpt/ib_srpt.c (revision 140eb5227767c6754742020a16d2691222b9c19b)
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, const 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 	int send_queue_depth;
299 
300 	iocp = (struct ib_dm_ioc_profile *)mad->data;
301 
302 	if (!slot || slot > 16) {
303 		mad->mad_hdr.status
304 			= cpu_to_be16(DM_MAD_STATUS_INVALID_FIELD);
305 		return;
306 	}
307 
308 	if (slot > 2) {
309 		mad->mad_hdr.status
310 			= cpu_to_be16(DM_MAD_STATUS_NO_IOC);
311 		return;
312 	}
313 
314 	if (sdev->use_srq)
315 		send_queue_depth = sdev->srq_size;
316 	else
317 		send_queue_depth = min(SRPT_RQ_SIZE,
318 				       sdev->device->attrs.max_qp_wr);
319 
320 	memset(iocp, 0, sizeof(*iocp));
321 	strcpy(iocp->id_string, SRPT_ID_STRING);
322 	iocp->guid = cpu_to_be64(srpt_service_guid);
323 	iocp->vendor_id = cpu_to_be32(sdev->device->attrs.vendor_id);
324 	iocp->device_id = cpu_to_be32(sdev->device->attrs.vendor_part_id);
325 	iocp->device_version = cpu_to_be16(sdev->device->attrs.hw_ver);
326 	iocp->subsys_vendor_id = cpu_to_be32(sdev->device->attrs.vendor_id);
327 	iocp->subsys_device_id = 0x0;
328 	iocp->io_class = cpu_to_be16(SRP_REV16A_IB_IO_CLASS);
329 	iocp->io_subclass = cpu_to_be16(SRP_IO_SUBCLASS);
330 	iocp->protocol = cpu_to_be16(SRP_PROTOCOL);
331 	iocp->protocol_version = cpu_to_be16(SRP_PROTOCOL_VERSION);
332 	iocp->send_queue_depth = cpu_to_be16(send_queue_depth);
333 	iocp->rdma_read_depth = 4;
334 	iocp->send_size = cpu_to_be32(srp_max_req_size);
335 	iocp->rdma_size = cpu_to_be32(min(sport->port_attrib.srp_max_rdma_size,
336 					  1U << 24));
337 	iocp->num_svc_entries = 1;
338 	iocp->op_cap_mask = SRP_SEND_TO_IOC | SRP_SEND_FROM_IOC |
339 		SRP_RDMA_READ_FROM_IOC | SRP_RDMA_WRITE_FROM_IOC;
340 
341 	mad->mad_hdr.status = 0;
342 }
343 
344 /**
345  * srpt_get_svc_entries() - Write ServiceEntries to a management datagram.
346  *
347  * See also section 16.3.3.5 ServiceEntries in the InfiniBand Architecture
348  * Specification. See also section B.7, table B.8 in the SRP r16a document.
349  */
350 static void srpt_get_svc_entries(u64 ioc_guid,
351 				 u16 slot, u8 hi, u8 lo, struct ib_dm_mad *mad)
352 {
353 	struct ib_dm_svc_entries *svc_entries;
354 
355 	WARN_ON(!ioc_guid);
356 
357 	if (!slot || slot > 16) {
358 		mad->mad_hdr.status
359 			= cpu_to_be16(DM_MAD_STATUS_INVALID_FIELD);
360 		return;
361 	}
362 
363 	if (slot > 2 || lo > hi || hi > 1) {
364 		mad->mad_hdr.status
365 			= cpu_to_be16(DM_MAD_STATUS_NO_IOC);
366 		return;
367 	}
368 
369 	svc_entries = (struct ib_dm_svc_entries *)mad->data;
370 	memset(svc_entries, 0, sizeof(*svc_entries));
371 	svc_entries->service_entries[0].id = cpu_to_be64(ioc_guid);
372 	snprintf(svc_entries->service_entries[0].name,
373 		 sizeof(svc_entries->service_entries[0].name),
374 		 "%s%016llx",
375 		 SRP_SERVICE_NAME_PREFIX,
376 		 ioc_guid);
377 
378 	mad->mad_hdr.status = 0;
379 }
380 
381 /**
382  * srpt_mgmt_method_get() - Process a received management datagram.
383  * @sp:      source port through which the MAD has been received.
384  * @rq_mad:  received MAD.
385  * @rsp_mad: response MAD.
386  */
387 static void srpt_mgmt_method_get(struct srpt_port *sp, struct ib_mad *rq_mad,
388 				 struct ib_dm_mad *rsp_mad)
389 {
390 	u16 attr_id;
391 	u32 slot;
392 	u8 hi, lo;
393 
394 	attr_id = be16_to_cpu(rq_mad->mad_hdr.attr_id);
395 	switch (attr_id) {
396 	case DM_ATTR_CLASS_PORT_INFO:
397 		srpt_get_class_port_info(rsp_mad);
398 		break;
399 	case DM_ATTR_IOU_INFO:
400 		srpt_get_iou(rsp_mad);
401 		break;
402 	case DM_ATTR_IOC_PROFILE:
403 		slot = be32_to_cpu(rq_mad->mad_hdr.attr_mod);
404 		srpt_get_ioc(sp, slot, rsp_mad);
405 		break;
406 	case DM_ATTR_SVC_ENTRIES:
407 		slot = be32_to_cpu(rq_mad->mad_hdr.attr_mod);
408 		hi = (u8) ((slot >> 8) & 0xff);
409 		lo = (u8) (slot & 0xff);
410 		slot = (u16) ((slot >> 16) & 0xffff);
411 		srpt_get_svc_entries(srpt_service_guid,
412 				     slot, hi, lo, rsp_mad);
413 		break;
414 	default:
415 		rsp_mad->mad_hdr.status =
416 		    cpu_to_be16(DM_MAD_STATUS_UNSUP_METHOD_ATTR);
417 		break;
418 	}
419 }
420 
421 /**
422  * srpt_mad_send_handler() - Post MAD-send callback function.
423  */
424 static void srpt_mad_send_handler(struct ib_mad_agent *mad_agent,
425 				  struct ib_mad_send_wc *mad_wc)
426 {
427 	rdma_destroy_ah(mad_wc->send_buf->ah);
428 	ib_free_send_mad(mad_wc->send_buf);
429 }
430 
431 /**
432  * srpt_mad_recv_handler() - MAD reception callback function.
433  */
434 static void srpt_mad_recv_handler(struct ib_mad_agent *mad_agent,
435 				  struct ib_mad_send_buf *send_buf,
436 				  struct ib_mad_recv_wc *mad_wc)
437 {
438 	struct srpt_port *sport = (struct srpt_port *)mad_agent->context;
439 	struct ib_ah *ah;
440 	struct ib_mad_send_buf *rsp;
441 	struct ib_dm_mad *dm_mad;
442 
443 	if (!mad_wc || !mad_wc->recv_buf.mad)
444 		return;
445 
446 	ah = ib_create_ah_from_wc(mad_agent->qp->pd, mad_wc->wc,
447 				  mad_wc->recv_buf.grh, mad_agent->port_num);
448 	if (IS_ERR(ah))
449 		goto err;
450 
451 	BUILD_BUG_ON(offsetof(struct ib_dm_mad, data) != IB_MGMT_DEVICE_HDR);
452 
453 	rsp = ib_create_send_mad(mad_agent, mad_wc->wc->src_qp,
454 				 mad_wc->wc->pkey_index, 0,
455 				 IB_MGMT_DEVICE_HDR, IB_MGMT_DEVICE_DATA,
456 				 GFP_KERNEL,
457 				 IB_MGMT_BASE_VERSION);
458 	if (IS_ERR(rsp))
459 		goto err_rsp;
460 
461 	rsp->ah = ah;
462 
463 	dm_mad = rsp->mad;
464 	memcpy(dm_mad, mad_wc->recv_buf.mad, sizeof(*dm_mad));
465 	dm_mad->mad_hdr.method = IB_MGMT_METHOD_GET_RESP;
466 	dm_mad->mad_hdr.status = 0;
467 
468 	switch (mad_wc->recv_buf.mad->mad_hdr.method) {
469 	case IB_MGMT_METHOD_GET:
470 		srpt_mgmt_method_get(sport, mad_wc->recv_buf.mad, dm_mad);
471 		break;
472 	case IB_MGMT_METHOD_SET:
473 		dm_mad->mad_hdr.status =
474 		    cpu_to_be16(DM_MAD_STATUS_UNSUP_METHOD_ATTR);
475 		break;
476 	default:
477 		dm_mad->mad_hdr.status =
478 		    cpu_to_be16(DM_MAD_STATUS_UNSUP_METHOD);
479 		break;
480 	}
481 
482 	if (!ib_post_send_mad(rsp, NULL)) {
483 		ib_free_recv_mad(mad_wc);
484 		/* will destroy_ah & free_send_mad in send completion */
485 		return;
486 	}
487 
488 	ib_free_send_mad(rsp);
489 
490 err_rsp:
491 	rdma_destroy_ah(ah);
492 err:
493 	ib_free_recv_mad(mad_wc);
494 }
495 
496 /**
497  * srpt_refresh_port() - Configure a HCA port.
498  *
499  * Enable InfiniBand management datagram processing, update the cached sm_lid,
500  * lid and gid values, and register a callback function for processing MADs
501  * on the specified port.
502  *
503  * Note: It is safe to call this function more than once for the same port.
504  */
505 static int srpt_refresh_port(struct srpt_port *sport)
506 {
507 	struct ib_mad_reg_req reg_req;
508 	struct ib_port_modify port_modify;
509 	struct ib_port_attr port_attr;
510 	__be16 *guid;
511 	int ret;
512 
513 	memset(&port_modify, 0, sizeof(port_modify));
514 	port_modify.set_port_cap_mask = IB_PORT_DEVICE_MGMT_SUP;
515 	port_modify.clr_port_cap_mask = 0;
516 
517 	ret = ib_modify_port(sport->sdev->device, sport->port, 0, &port_modify);
518 	if (ret)
519 		goto err_mod_port;
520 
521 	ret = ib_query_port(sport->sdev->device, sport->port, &port_attr);
522 	if (ret)
523 		goto err_query_port;
524 
525 	sport->sm_lid = port_attr.sm_lid;
526 	sport->lid = port_attr.lid;
527 
528 	ret = ib_query_gid(sport->sdev->device, sport->port, 0, &sport->gid,
529 			   NULL);
530 	if (ret)
531 		goto err_query_port;
532 
533 	sport->port_guid_wwn.priv = sport;
534 	guid = (__be16 *)&sport->gid.global.interface_id;
535 	snprintf(sport->port_guid, sizeof(sport->port_guid),
536 		 "%04x:%04x:%04x:%04x",
537 		 be16_to_cpu(guid[0]), be16_to_cpu(guid[1]),
538 		 be16_to_cpu(guid[2]), be16_to_cpu(guid[3]));
539 	sport->port_gid_wwn.priv = sport;
540 	snprintf(sport->port_gid, sizeof(sport->port_gid),
541 		 "0x%016llx%016llx",
542 		 be64_to_cpu(sport->gid.global.subnet_prefix),
543 		 be64_to_cpu(sport->gid.global.interface_id));
544 
545 	if (!sport->mad_agent) {
546 		memset(&reg_req, 0, sizeof(reg_req));
547 		reg_req.mgmt_class = IB_MGMT_CLASS_DEVICE_MGMT;
548 		reg_req.mgmt_class_version = IB_MGMT_BASE_VERSION;
549 		set_bit(IB_MGMT_METHOD_GET, reg_req.method_mask);
550 		set_bit(IB_MGMT_METHOD_SET, reg_req.method_mask);
551 
552 		sport->mad_agent = ib_register_mad_agent(sport->sdev->device,
553 							 sport->port,
554 							 IB_QPT_GSI,
555 							 &reg_req, 0,
556 							 srpt_mad_send_handler,
557 							 srpt_mad_recv_handler,
558 							 sport, 0);
559 		if (IS_ERR(sport->mad_agent)) {
560 			ret = PTR_ERR(sport->mad_agent);
561 			sport->mad_agent = NULL;
562 			goto err_query_port;
563 		}
564 	}
565 
566 	return 0;
567 
568 err_query_port:
569 
570 	port_modify.set_port_cap_mask = 0;
571 	port_modify.clr_port_cap_mask = IB_PORT_DEVICE_MGMT_SUP;
572 	ib_modify_port(sport->sdev->device, sport->port, 0, &port_modify);
573 
574 err_mod_port:
575 
576 	return ret;
577 }
578 
579 /**
580  * srpt_unregister_mad_agent() - Unregister MAD callback functions.
581  *
582  * Note: It is safe to call this function more than once for the same device.
583  */
584 static void srpt_unregister_mad_agent(struct srpt_device *sdev)
585 {
586 	struct ib_port_modify port_modify = {
587 		.clr_port_cap_mask = IB_PORT_DEVICE_MGMT_SUP,
588 	};
589 	struct srpt_port *sport;
590 	int i;
591 
592 	for (i = 1; i <= sdev->device->phys_port_cnt; i++) {
593 		sport = &sdev->port[i - 1];
594 		WARN_ON(sport->port != i);
595 		if (ib_modify_port(sdev->device, i, 0, &port_modify) < 0)
596 			pr_err("disabling MAD processing failed.\n");
597 		if (sport->mad_agent) {
598 			ib_unregister_mad_agent(sport->mad_agent);
599 			sport->mad_agent = NULL;
600 		}
601 	}
602 }
603 
604 /**
605  * srpt_alloc_ioctx() - Allocate an SRPT I/O context structure.
606  */
607 static struct srpt_ioctx *srpt_alloc_ioctx(struct srpt_device *sdev,
608 					   int ioctx_size, int dma_size,
609 					   enum dma_data_direction dir)
610 {
611 	struct srpt_ioctx *ioctx;
612 
613 	ioctx = kmalloc(ioctx_size, GFP_KERNEL);
614 	if (!ioctx)
615 		goto err;
616 
617 	ioctx->buf = kmalloc(dma_size, GFP_KERNEL);
618 	if (!ioctx->buf)
619 		goto err_free_ioctx;
620 
621 	ioctx->dma = ib_dma_map_single(sdev->device, ioctx->buf, dma_size, dir);
622 	if (ib_dma_mapping_error(sdev->device, ioctx->dma))
623 		goto err_free_buf;
624 
625 	return ioctx;
626 
627 err_free_buf:
628 	kfree(ioctx->buf);
629 err_free_ioctx:
630 	kfree(ioctx);
631 err:
632 	return NULL;
633 }
634 
635 /**
636  * srpt_free_ioctx() - Free an SRPT I/O context structure.
637  */
638 static void srpt_free_ioctx(struct srpt_device *sdev, struct srpt_ioctx *ioctx,
639 			    int dma_size, enum dma_data_direction dir)
640 {
641 	if (!ioctx)
642 		return;
643 
644 	ib_dma_unmap_single(sdev->device, ioctx->dma, dma_size, dir);
645 	kfree(ioctx->buf);
646 	kfree(ioctx);
647 }
648 
649 /**
650  * srpt_alloc_ioctx_ring() - Allocate a ring of SRPT I/O context structures.
651  * @sdev:       Device to allocate the I/O context ring for.
652  * @ring_size:  Number of elements in the I/O context ring.
653  * @ioctx_size: I/O context size.
654  * @dma_size:   DMA buffer size.
655  * @dir:        DMA data direction.
656  */
657 static struct srpt_ioctx **srpt_alloc_ioctx_ring(struct srpt_device *sdev,
658 				int ring_size, int ioctx_size,
659 				int dma_size, enum dma_data_direction dir)
660 {
661 	struct srpt_ioctx **ring;
662 	int i;
663 
664 	WARN_ON(ioctx_size != sizeof(struct srpt_recv_ioctx)
665 		&& ioctx_size != sizeof(struct srpt_send_ioctx));
666 
667 	ring = kmalloc(ring_size * sizeof(ring[0]), GFP_KERNEL);
668 	if (!ring)
669 		goto out;
670 	for (i = 0; i < ring_size; ++i) {
671 		ring[i] = srpt_alloc_ioctx(sdev, ioctx_size, dma_size, dir);
672 		if (!ring[i])
673 			goto err;
674 		ring[i]->index = i;
675 	}
676 	goto out;
677 
678 err:
679 	while (--i >= 0)
680 		srpt_free_ioctx(sdev, ring[i], dma_size, dir);
681 	kfree(ring);
682 	ring = NULL;
683 out:
684 	return ring;
685 }
686 
687 /**
688  * srpt_free_ioctx_ring() - Free the ring of SRPT I/O context structures.
689  */
690 static void srpt_free_ioctx_ring(struct srpt_ioctx **ioctx_ring,
691 				 struct srpt_device *sdev, int ring_size,
692 				 int dma_size, enum dma_data_direction dir)
693 {
694 	int i;
695 
696 	if (!ioctx_ring)
697 		return;
698 
699 	for (i = 0; i < ring_size; ++i)
700 		srpt_free_ioctx(sdev, ioctx_ring[i], dma_size, dir);
701 	kfree(ioctx_ring);
702 }
703 
704 /**
705  * srpt_get_cmd_state() - Get the state of a SCSI command.
706  */
707 static enum srpt_command_state srpt_get_cmd_state(struct srpt_send_ioctx *ioctx)
708 {
709 	enum srpt_command_state state;
710 	unsigned long flags;
711 
712 	BUG_ON(!ioctx);
713 
714 	spin_lock_irqsave(&ioctx->spinlock, flags);
715 	state = ioctx->state;
716 	spin_unlock_irqrestore(&ioctx->spinlock, flags);
717 	return state;
718 }
719 
720 /**
721  * srpt_set_cmd_state() - Set the state of a SCSI command.
722  *
723  * Does not modify the state of aborted commands. Returns the previous command
724  * state.
725  */
726 static enum srpt_command_state srpt_set_cmd_state(struct srpt_send_ioctx *ioctx,
727 						  enum srpt_command_state new)
728 {
729 	enum srpt_command_state previous;
730 	unsigned long flags;
731 
732 	BUG_ON(!ioctx);
733 
734 	spin_lock_irqsave(&ioctx->spinlock, flags);
735 	previous = ioctx->state;
736 	if (previous != SRPT_STATE_DONE)
737 		ioctx->state = new;
738 	spin_unlock_irqrestore(&ioctx->spinlock, flags);
739 
740 	return previous;
741 }
742 
743 /**
744  * srpt_test_and_set_cmd_state() - Test and set the state of a command.
745  *
746  * Returns true if and only if the previous command state was equal to 'old'.
747  */
748 static bool srpt_test_and_set_cmd_state(struct srpt_send_ioctx *ioctx,
749 					enum srpt_command_state old,
750 					enum srpt_command_state new)
751 {
752 	enum srpt_command_state previous;
753 	unsigned long flags;
754 
755 	WARN_ON(!ioctx);
756 	WARN_ON(old == SRPT_STATE_DONE);
757 	WARN_ON(new == SRPT_STATE_NEW);
758 
759 	spin_lock_irqsave(&ioctx->spinlock, flags);
760 	previous = ioctx->state;
761 	if (previous == old)
762 		ioctx->state = new;
763 	spin_unlock_irqrestore(&ioctx->spinlock, flags);
764 	return previous == old;
765 }
766 
767 /**
768  * srpt_post_recv() - Post an IB receive request.
769  */
770 static int srpt_post_recv(struct srpt_device *sdev, struct srpt_rdma_ch *ch,
771 			  struct srpt_recv_ioctx *ioctx)
772 {
773 	struct ib_sge list;
774 	struct ib_recv_wr wr, *bad_wr;
775 
776 	BUG_ON(!sdev);
777 	list.addr = ioctx->ioctx.dma;
778 	list.length = srp_max_req_size;
779 	list.lkey = sdev->lkey;
780 
781 	ioctx->ioctx.cqe.done = srpt_recv_done;
782 	wr.wr_cqe = &ioctx->ioctx.cqe;
783 	wr.next = NULL;
784 	wr.sg_list = &list;
785 	wr.num_sge = 1;
786 
787 	if (sdev->use_srq)
788 		return ib_post_srq_recv(sdev->srq, &wr, &bad_wr);
789 	else
790 		return ib_post_recv(ch->qp, &wr, &bad_wr);
791 }
792 
793 /**
794  * srpt_zerolength_write() - Perform a zero-length RDMA write.
795  *
796  * A quote from the InfiniBand specification: C9-88: For an HCA responder
797  * using Reliable Connection service, for each zero-length RDMA READ or WRITE
798  * request, the R_Key shall not be validated, even if the request includes
799  * Immediate data.
800  */
801 static int srpt_zerolength_write(struct srpt_rdma_ch *ch)
802 {
803 	struct ib_send_wr wr, *bad_wr;
804 
805 	memset(&wr, 0, sizeof(wr));
806 	wr.opcode = IB_WR_RDMA_WRITE;
807 	wr.wr_cqe = &ch->zw_cqe;
808 	wr.send_flags = IB_SEND_SIGNALED;
809 	return ib_post_send(ch->qp, &wr, &bad_wr);
810 }
811 
812 static void srpt_zerolength_write_done(struct ib_cq *cq, struct ib_wc *wc)
813 {
814 	struct srpt_rdma_ch *ch = cq->cq_context;
815 
816 	if (wc->status == IB_WC_SUCCESS) {
817 		srpt_process_wait_list(ch);
818 	} else {
819 		if (srpt_set_ch_state(ch, CH_DISCONNECTED))
820 			schedule_work(&ch->release_work);
821 		else
822 			WARN_ONCE(1, "%s-%d\n", ch->sess_name, ch->qp->qp_num);
823 	}
824 }
825 
826 static int srpt_alloc_rw_ctxs(struct srpt_send_ioctx *ioctx,
827 		struct srp_direct_buf *db, int nbufs, struct scatterlist **sg,
828 		unsigned *sg_cnt)
829 {
830 	enum dma_data_direction dir = target_reverse_dma_direction(&ioctx->cmd);
831 	struct srpt_rdma_ch *ch = ioctx->ch;
832 	struct scatterlist *prev = NULL;
833 	unsigned prev_nents;
834 	int ret, i;
835 
836 	if (nbufs == 1) {
837 		ioctx->rw_ctxs = &ioctx->s_rw_ctx;
838 	} else {
839 		ioctx->rw_ctxs = kmalloc_array(nbufs, sizeof(*ioctx->rw_ctxs),
840 			GFP_KERNEL);
841 		if (!ioctx->rw_ctxs)
842 			return -ENOMEM;
843 	}
844 
845 	for (i = ioctx->n_rw_ctx; i < nbufs; i++, db++) {
846 		struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
847 		u64 remote_addr = be64_to_cpu(db->va);
848 		u32 size = be32_to_cpu(db->len);
849 		u32 rkey = be32_to_cpu(db->key);
850 
851 		ret = target_alloc_sgl(&ctx->sg, &ctx->nents, size, false,
852 				i < nbufs - 1);
853 		if (ret)
854 			goto unwind;
855 
856 		ret = rdma_rw_ctx_init(&ctx->rw, ch->qp, ch->sport->port,
857 				ctx->sg, ctx->nents, 0, remote_addr, rkey, dir);
858 		if (ret < 0) {
859 			target_free_sgl(ctx->sg, ctx->nents);
860 			goto unwind;
861 		}
862 
863 		ioctx->n_rdma += ret;
864 		ioctx->n_rw_ctx++;
865 
866 		if (prev) {
867 			sg_unmark_end(&prev[prev_nents - 1]);
868 			sg_chain(prev, prev_nents + 1, ctx->sg);
869 		} else {
870 			*sg = ctx->sg;
871 		}
872 
873 		prev = ctx->sg;
874 		prev_nents = ctx->nents;
875 
876 		*sg_cnt += ctx->nents;
877 	}
878 
879 	return 0;
880 
881 unwind:
882 	while (--i >= 0) {
883 		struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
884 
885 		rdma_rw_ctx_destroy(&ctx->rw, ch->qp, ch->sport->port,
886 				ctx->sg, ctx->nents, dir);
887 		target_free_sgl(ctx->sg, ctx->nents);
888 	}
889 	if (ioctx->rw_ctxs != &ioctx->s_rw_ctx)
890 		kfree(ioctx->rw_ctxs);
891 	return ret;
892 }
893 
894 static void srpt_free_rw_ctxs(struct srpt_rdma_ch *ch,
895 				    struct srpt_send_ioctx *ioctx)
896 {
897 	enum dma_data_direction dir = target_reverse_dma_direction(&ioctx->cmd);
898 	int i;
899 
900 	for (i = 0; i < ioctx->n_rw_ctx; i++) {
901 		struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
902 
903 		rdma_rw_ctx_destroy(&ctx->rw, ch->qp, ch->sport->port,
904 				ctx->sg, ctx->nents, dir);
905 		target_free_sgl(ctx->sg, ctx->nents);
906 	}
907 
908 	if (ioctx->rw_ctxs != &ioctx->s_rw_ctx)
909 		kfree(ioctx->rw_ctxs);
910 }
911 
912 static inline void *srpt_get_desc_buf(struct srp_cmd *srp_cmd)
913 {
914 	/*
915 	 * The pointer computations below will only be compiled correctly
916 	 * if srp_cmd::add_data is declared as s8*, u8*, s8[] or u8[], so check
917 	 * whether srp_cmd::add_data has been declared as a byte pointer.
918 	 */
919 	BUILD_BUG_ON(!__same_type(srp_cmd->add_data[0], (s8)0) &&
920 		     !__same_type(srp_cmd->add_data[0], (u8)0));
921 
922 	/*
923 	 * According to the SRP spec, the lower two bits of the 'ADDITIONAL
924 	 * CDB LENGTH' field are reserved and the size in bytes of this field
925 	 * is four times the value specified in bits 3..7. Hence the "& ~3".
926 	 */
927 	return srp_cmd->add_data + (srp_cmd->add_cdb_len & ~3);
928 }
929 
930 /**
931  * srpt_get_desc_tbl() - Parse the data descriptors of an SRP_CMD request.
932  * @ioctx: Pointer to the I/O context associated with the request.
933  * @srp_cmd: Pointer to the SRP_CMD request data.
934  * @dir: Pointer to the variable to which the transfer direction will be
935  *   written.
936  * @data_len: Pointer to the variable to which the total data length of all
937  *   descriptors in the SRP_CMD request will be written.
938  *
939  * This function initializes ioctx->nrbuf and ioctx->r_bufs.
940  *
941  * Returns -EINVAL when the SRP_CMD request contains inconsistent descriptors;
942  * -ENOMEM when memory allocation fails and zero upon success.
943  */
944 static int srpt_get_desc_tbl(struct srpt_send_ioctx *ioctx,
945 		struct srp_cmd *srp_cmd, enum dma_data_direction *dir,
946 		struct scatterlist **sg, unsigned *sg_cnt, u64 *data_len)
947 {
948 	BUG_ON(!dir);
949 	BUG_ON(!data_len);
950 
951 	/*
952 	 * The lower four bits of the buffer format field contain the DATA-IN
953 	 * buffer descriptor format, and the highest four bits contain the
954 	 * DATA-OUT buffer descriptor format.
955 	 */
956 	if (srp_cmd->buf_fmt & 0xf)
957 		/* DATA-IN: transfer data from target to initiator (read). */
958 		*dir = DMA_FROM_DEVICE;
959 	else if (srp_cmd->buf_fmt >> 4)
960 		/* DATA-OUT: transfer data from initiator to target (write). */
961 		*dir = DMA_TO_DEVICE;
962 	else
963 		*dir = DMA_NONE;
964 
965 	/* initialize data_direction early as srpt_alloc_rw_ctxs needs it */
966 	ioctx->cmd.data_direction = *dir;
967 
968 	if (((srp_cmd->buf_fmt & 0xf) == SRP_DATA_DESC_DIRECT) ||
969 	    ((srp_cmd->buf_fmt >> 4) == SRP_DATA_DESC_DIRECT)) {
970 	    	struct srp_direct_buf *db = srpt_get_desc_buf(srp_cmd);
971 
972 		*data_len = be32_to_cpu(db->len);
973 		return srpt_alloc_rw_ctxs(ioctx, db, 1, sg, sg_cnt);
974 	} else if (((srp_cmd->buf_fmt & 0xf) == SRP_DATA_DESC_INDIRECT) ||
975 		   ((srp_cmd->buf_fmt >> 4) == SRP_DATA_DESC_INDIRECT)) {
976 		struct srp_indirect_buf *idb = srpt_get_desc_buf(srp_cmd);
977 		int nbufs = be32_to_cpu(idb->table_desc.len) /
978 				sizeof(struct srp_direct_buf);
979 
980 		if (nbufs >
981 		    (srp_cmd->data_out_desc_cnt + srp_cmd->data_in_desc_cnt)) {
982 			pr_err("received unsupported SRP_CMD request"
983 			       " type (%u out + %u in != %u / %zu)\n",
984 			       srp_cmd->data_out_desc_cnt,
985 			       srp_cmd->data_in_desc_cnt,
986 			       be32_to_cpu(idb->table_desc.len),
987 			       sizeof(struct srp_direct_buf));
988 			return -EINVAL;
989 		}
990 
991 		*data_len = be32_to_cpu(idb->len);
992 		return srpt_alloc_rw_ctxs(ioctx, idb->desc_list, nbufs,
993 				sg, sg_cnt);
994 	} else {
995 		*data_len = 0;
996 		return 0;
997 	}
998 }
999 
1000 /**
1001  * srpt_init_ch_qp() - Initialize queue pair attributes.
1002  *
1003  * Initialized the attributes of queue pair 'qp' by allowing local write,
1004  * remote read and remote write. Also transitions 'qp' to state IB_QPS_INIT.
1005  */
1006 static int srpt_init_ch_qp(struct srpt_rdma_ch *ch, struct ib_qp *qp)
1007 {
1008 	struct ib_qp_attr *attr;
1009 	int ret;
1010 
1011 	attr = kzalloc(sizeof(*attr), GFP_KERNEL);
1012 	if (!attr)
1013 		return -ENOMEM;
1014 
1015 	attr->qp_state = IB_QPS_INIT;
1016 	attr->qp_access_flags = IB_ACCESS_LOCAL_WRITE;
1017 	attr->port_num = ch->sport->port;
1018 	attr->pkey_index = 0;
1019 
1020 	ret = ib_modify_qp(qp, attr,
1021 			   IB_QP_STATE | IB_QP_ACCESS_FLAGS | IB_QP_PORT |
1022 			   IB_QP_PKEY_INDEX);
1023 
1024 	kfree(attr);
1025 	return ret;
1026 }
1027 
1028 /**
1029  * srpt_ch_qp_rtr() - Change the state of a channel to 'ready to receive' (RTR).
1030  * @ch: channel of the queue pair.
1031  * @qp: queue pair to change the state of.
1032  *
1033  * Returns zero upon success and a negative value upon failure.
1034  *
1035  * Note: currently a struct ib_qp_attr takes 136 bytes on a 64-bit system.
1036  * If this structure ever becomes larger, it might be necessary to allocate
1037  * it dynamically instead of on the stack.
1038  */
1039 static int srpt_ch_qp_rtr(struct srpt_rdma_ch *ch, struct ib_qp *qp)
1040 {
1041 	struct ib_qp_attr qp_attr;
1042 	int attr_mask;
1043 	int ret;
1044 
1045 	qp_attr.qp_state = IB_QPS_RTR;
1046 	ret = ib_cm_init_qp_attr(ch->cm_id, &qp_attr, &attr_mask);
1047 	if (ret)
1048 		goto out;
1049 
1050 	qp_attr.max_dest_rd_atomic = 4;
1051 
1052 	ret = ib_modify_qp(qp, &qp_attr, attr_mask);
1053 
1054 out:
1055 	return ret;
1056 }
1057 
1058 /**
1059  * srpt_ch_qp_rts() - Change the state of a channel to 'ready to send' (RTS).
1060  * @ch: channel of the queue pair.
1061  * @qp: queue pair to change the state of.
1062  *
1063  * Returns zero upon success and a negative value upon failure.
1064  *
1065  * Note: currently a struct ib_qp_attr takes 136 bytes on a 64-bit system.
1066  * If this structure ever becomes larger, it might be necessary to allocate
1067  * it dynamically instead of on the stack.
1068  */
1069 static int srpt_ch_qp_rts(struct srpt_rdma_ch *ch, struct ib_qp *qp)
1070 {
1071 	struct ib_qp_attr qp_attr;
1072 	int attr_mask;
1073 	int ret;
1074 
1075 	qp_attr.qp_state = IB_QPS_RTS;
1076 	ret = ib_cm_init_qp_attr(ch->cm_id, &qp_attr, &attr_mask);
1077 	if (ret)
1078 		goto out;
1079 
1080 	qp_attr.max_rd_atomic = 4;
1081 
1082 	ret = ib_modify_qp(qp, &qp_attr, attr_mask);
1083 
1084 out:
1085 	return ret;
1086 }
1087 
1088 /**
1089  * srpt_ch_qp_err() - Set the channel queue pair state to 'error'.
1090  */
1091 static int srpt_ch_qp_err(struct srpt_rdma_ch *ch)
1092 {
1093 	struct ib_qp_attr qp_attr;
1094 
1095 	qp_attr.qp_state = IB_QPS_ERR;
1096 	return ib_modify_qp(ch->qp, &qp_attr, IB_QP_STATE);
1097 }
1098 
1099 /**
1100  * srpt_get_send_ioctx() - Obtain an I/O context for sending to the initiator.
1101  */
1102 static struct srpt_send_ioctx *srpt_get_send_ioctx(struct srpt_rdma_ch *ch)
1103 {
1104 	struct srpt_send_ioctx *ioctx;
1105 	unsigned long flags;
1106 
1107 	BUG_ON(!ch);
1108 
1109 	ioctx = NULL;
1110 	spin_lock_irqsave(&ch->spinlock, flags);
1111 	if (!list_empty(&ch->free_list)) {
1112 		ioctx = list_first_entry(&ch->free_list,
1113 					 struct srpt_send_ioctx, free_list);
1114 		list_del(&ioctx->free_list);
1115 	}
1116 	spin_unlock_irqrestore(&ch->spinlock, flags);
1117 
1118 	if (!ioctx)
1119 		return ioctx;
1120 
1121 	BUG_ON(ioctx->ch != ch);
1122 	spin_lock_init(&ioctx->spinlock);
1123 	ioctx->state = SRPT_STATE_NEW;
1124 	ioctx->n_rdma = 0;
1125 	ioctx->n_rw_ctx = 0;
1126 	init_completion(&ioctx->tx_done);
1127 	ioctx->queue_status_only = false;
1128 	/*
1129 	 * transport_init_se_cmd() does not initialize all fields, so do it
1130 	 * here.
1131 	 */
1132 	memset(&ioctx->cmd, 0, sizeof(ioctx->cmd));
1133 	memset(&ioctx->sense_data, 0, sizeof(ioctx->sense_data));
1134 
1135 	return ioctx;
1136 }
1137 
1138 /**
1139  * srpt_abort_cmd() - Abort a SCSI command.
1140  * @ioctx:   I/O context associated with the SCSI command.
1141  * @context: Preferred execution context.
1142  */
1143 static int srpt_abort_cmd(struct srpt_send_ioctx *ioctx)
1144 {
1145 	enum srpt_command_state state;
1146 	unsigned long flags;
1147 
1148 	BUG_ON(!ioctx);
1149 
1150 	/*
1151 	 * If the command is in a state where the target core is waiting for
1152 	 * the ib_srpt driver, change the state to the next state.
1153 	 */
1154 
1155 	spin_lock_irqsave(&ioctx->spinlock, flags);
1156 	state = ioctx->state;
1157 	switch (state) {
1158 	case SRPT_STATE_NEED_DATA:
1159 		ioctx->state = SRPT_STATE_DATA_IN;
1160 		break;
1161 	case SRPT_STATE_CMD_RSP_SENT:
1162 	case SRPT_STATE_MGMT_RSP_SENT:
1163 		ioctx->state = SRPT_STATE_DONE;
1164 		break;
1165 	default:
1166 		WARN_ONCE(true, "%s: unexpected I/O context state %d\n",
1167 			  __func__, state);
1168 		break;
1169 	}
1170 	spin_unlock_irqrestore(&ioctx->spinlock, flags);
1171 
1172 	pr_debug("Aborting cmd with state %d -> %d and tag %lld\n", state,
1173 		 ioctx->state, ioctx->cmd.tag);
1174 
1175 	switch (state) {
1176 	case SRPT_STATE_NEW:
1177 	case SRPT_STATE_DATA_IN:
1178 	case SRPT_STATE_MGMT:
1179 	case SRPT_STATE_DONE:
1180 		/*
1181 		 * Do nothing - defer abort processing until
1182 		 * srpt_queue_response() is invoked.
1183 		 */
1184 		break;
1185 	case SRPT_STATE_NEED_DATA:
1186 		pr_debug("tag %#llx: RDMA read error\n", ioctx->cmd.tag);
1187 		transport_generic_request_failure(&ioctx->cmd,
1188 					TCM_CHECK_CONDITION_ABORT_CMD);
1189 		break;
1190 	case SRPT_STATE_CMD_RSP_SENT:
1191 		/*
1192 		 * SRP_RSP sending failed or the SRP_RSP send completion has
1193 		 * not been received in time.
1194 		 */
1195 		transport_generic_free_cmd(&ioctx->cmd, 0);
1196 		break;
1197 	case SRPT_STATE_MGMT_RSP_SENT:
1198 		transport_generic_free_cmd(&ioctx->cmd, 0);
1199 		break;
1200 	default:
1201 		WARN(1, "Unexpected command state (%d)", state);
1202 		break;
1203 	}
1204 
1205 	return state;
1206 }
1207 
1208 /**
1209  * XXX: what is now target_execute_cmd used to be asynchronous, and unmapping
1210  * the data that has been transferred via IB RDMA had to be postponed until the
1211  * check_stop_free() callback.  None of this is necessary anymore and needs to
1212  * be cleaned up.
1213  */
1214 static void srpt_rdma_read_done(struct ib_cq *cq, struct ib_wc *wc)
1215 {
1216 	struct srpt_rdma_ch *ch = cq->cq_context;
1217 	struct srpt_send_ioctx *ioctx =
1218 		container_of(wc->wr_cqe, struct srpt_send_ioctx, rdma_cqe);
1219 
1220 	WARN_ON(ioctx->n_rdma <= 0);
1221 	atomic_add(ioctx->n_rdma, &ch->sq_wr_avail);
1222 	ioctx->n_rdma = 0;
1223 
1224 	if (unlikely(wc->status != IB_WC_SUCCESS)) {
1225 		pr_info("RDMA_READ for ioctx 0x%p failed with status %d\n",
1226 			ioctx, wc->status);
1227 		srpt_abort_cmd(ioctx);
1228 		return;
1229 	}
1230 
1231 	if (srpt_test_and_set_cmd_state(ioctx, SRPT_STATE_NEED_DATA,
1232 					SRPT_STATE_DATA_IN))
1233 		target_execute_cmd(&ioctx->cmd);
1234 	else
1235 		pr_err("%s[%d]: wrong state = %d\n", __func__,
1236 		       __LINE__, srpt_get_cmd_state(ioctx));
1237 }
1238 
1239 /**
1240  * srpt_build_cmd_rsp() - Build an SRP_RSP response.
1241  * @ch: RDMA channel through which the request has been received.
1242  * @ioctx: I/O context associated with the SRP_CMD request. The response will
1243  *   be built in the buffer ioctx->buf points at and hence this function will
1244  *   overwrite the request data.
1245  * @tag: tag of the request for which this response is being generated.
1246  * @status: value for the STATUS field of the SRP_RSP information unit.
1247  *
1248  * Returns the size in bytes of the SRP_RSP response.
1249  *
1250  * An SRP_RSP response contains a SCSI status or service response. See also
1251  * section 6.9 in the SRP r16a document for the format of an SRP_RSP
1252  * response. See also SPC-2 for more information about sense data.
1253  */
1254 static int srpt_build_cmd_rsp(struct srpt_rdma_ch *ch,
1255 			      struct srpt_send_ioctx *ioctx, u64 tag,
1256 			      int status)
1257 {
1258 	struct srp_rsp *srp_rsp;
1259 	const u8 *sense_data;
1260 	int sense_data_len, max_sense_len;
1261 
1262 	/*
1263 	 * The lowest bit of all SAM-3 status codes is zero (see also
1264 	 * paragraph 5.3 in SAM-3).
1265 	 */
1266 	WARN_ON(status & 1);
1267 
1268 	srp_rsp = ioctx->ioctx.buf;
1269 	BUG_ON(!srp_rsp);
1270 
1271 	sense_data = ioctx->sense_data;
1272 	sense_data_len = ioctx->cmd.scsi_sense_length;
1273 	WARN_ON(sense_data_len > sizeof(ioctx->sense_data));
1274 
1275 	memset(srp_rsp, 0, sizeof(*srp_rsp));
1276 	srp_rsp->opcode = SRP_RSP;
1277 	srp_rsp->req_lim_delta =
1278 		cpu_to_be32(1 + atomic_xchg(&ch->req_lim_delta, 0));
1279 	srp_rsp->tag = tag;
1280 	srp_rsp->status = status;
1281 
1282 	if (sense_data_len) {
1283 		BUILD_BUG_ON(MIN_MAX_RSP_SIZE <= sizeof(*srp_rsp));
1284 		max_sense_len = ch->max_ti_iu_len - sizeof(*srp_rsp);
1285 		if (sense_data_len > max_sense_len) {
1286 			pr_warn("truncated sense data from %d to %d"
1287 				" bytes\n", sense_data_len, max_sense_len);
1288 			sense_data_len = max_sense_len;
1289 		}
1290 
1291 		srp_rsp->flags |= SRP_RSP_FLAG_SNSVALID;
1292 		srp_rsp->sense_data_len = cpu_to_be32(sense_data_len);
1293 		memcpy(srp_rsp + 1, sense_data, sense_data_len);
1294 	}
1295 
1296 	return sizeof(*srp_rsp) + sense_data_len;
1297 }
1298 
1299 /**
1300  * srpt_build_tskmgmt_rsp() - Build a task management response.
1301  * @ch:       RDMA channel through which the request has been received.
1302  * @ioctx:    I/O context in which the SRP_RSP response will be built.
1303  * @rsp_code: RSP_CODE that will be stored in the response.
1304  * @tag:      Tag of the request for which this response is being generated.
1305  *
1306  * Returns the size in bytes of the SRP_RSP response.
1307  *
1308  * An SRP_RSP response contains a SCSI status or service response. See also
1309  * section 6.9 in the SRP r16a document for the format of an SRP_RSP
1310  * response.
1311  */
1312 static int srpt_build_tskmgmt_rsp(struct srpt_rdma_ch *ch,
1313 				  struct srpt_send_ioctx *ioctx,
1314 				  u8 rsp_code, u64 tag)
1315 {
1316 	struct srp_rsp *srp_rsp;
1317 	int resp_data_len;
1318 	int resp_len;
1319 
1320 	resp_data_len = 4;
1321 	resp_len = sizeof(*srp_rsp) + resp_data_len;
1322 
1323 	srp_rsp = ioctx->ioctx.buf;
1324 	BUG_ON(!srp_rsp);
1325 	memset(srp_rsp, 0, sizeof(*srp_rsp));
1326 
1327 	srp_rsp->opcode = SRP_RSP;
1328 	srp_rsp->req_lim_delta =
1329 		cpu_to_be32(1 + atomic_xchg(&ch->req_lim_delta, 0));
1330 	srp_rsp->tag = tag;
1331 
1332 	srp_rsp->flags |= SRP_RSP_FLAG_RSPVALID;
1333 	srp_rsp->resp_data_len = cpu_to_be32(resp_data_len);
1334 	srp_rsp->data[3] = rsp_code;
1335 
1336 	return resp_len;
1337 }
1338 
1339 static int srpt_check_stop_free(struct se_cmd *cmd)
1340 {
1341 	struct srpt_send_ioctx *ioctx = container_of(cmd,
1342 				struct srpt_send_ioctx, cmd);
1343 
1344 	return target_put_sess_cmd(&ioctx->cmd);
1345 }
1346 
1347 /**
1348  * srpt_handle_cmd() - Process SRP_CMD.
1349  */
1350 static void srpt_handle_cmd(struct srpt_rdma_ch *ch,
1351 			    struct srpt_recv_ioctx *recv_ioctx,
1352 			    struct srpt_send_ioctx *send_ioctx)
1353 {
1354 	struct se_cmd *cmd;
1355 	struct srp_cmd *srp_cmd;
1356 	struct scatterlist *sg = NULL;
1357 	unsigned sg_cnt = 0;
1358 	u64 data_len;
1359 	enum dma_data_direction dir;
1360 	int rc;
1361 
1362 	BUG_ON(!send_ioctx);
1363 
1364 	srp_cmd = recv_ioctx->ioctx.buf;
1365 	cmd = &send_ioctx->cmd;
1366 	cmd->tag = srp_cmd->tag;
1367 
1368 	switch (srp_cmd->task_attr) {
1369 	case SRP_CMD_SIMPLE_Q:
1370 		cmd->sam_task_attr = TCM_SIMPLE_TAG;
1371 		break;
1372 	case SRP_CMD_ORDERED_Q:
1373 	default:
1374 		cmd->sam_task_attr = TCM_ORDERED_TAG;
1375 		break;
1376 	case SRP_CMD_HEAD_OF_Q:
1377 		cmd->sam_task_attr = TCM_HEAD_TAG;
1378 		break;
1379 	case SRP_CMD_ACA:
1380 		cmd->sam_task_attr = TCM_ACA_TAG;
1381 		break;
1382 	}
1383 
1384 	rc = srpt_get_desc_tbl(send_ioctx, srp_cmd, &dir, &sg, &sg_cnt,
1385 			&data_len);
1386 	if (rc) {
1387 		if (rc != -EAGAIN) {
1388 			pr_err("0x%llx: parsing SRP descriptor table failed.\n",
1389 			       srp_cmd->tag);
1390 		}
1391 		goto release_ioctx;
1392 	}
1393 
1394 	rc = target_submit_cmd_map_sgls(cmd, ch->sess, srp_cmd->cdb,
1395 			       &send_ioctx->sense_data[0],
1396 			       scsilun_to_int(&srp_cmd->lun), data_len,
1397 			       TCM_SIMPLE_TAG, dir, TARGET_SCF_ACK_KREF,
1398 			       sg, sg_cnt, NULL, 0, NULL, 0);
1399 	if (rc != 0) {
1400 		pr_debug("target_submit_cmd() returned %d for tag %#llx\n", rc,
1401 			 srp_cmd->tag);
1402 		goto release_ioctx;
1403 	}
1404 	return;
1405 
1406 release_ioctx:
1407 	send_ioctx->state = SRPT_STATE_DONE;
1408 	srpt_release_cmd(cmd);
1409 }
1410 
1411 static int srp_tmr_to_tcm(int fn)
1412 {
1413 	switch (fn) {
1414 	case SRP_TSK_ABORT_TASK:
1415 		return TMR_ABORT_TASK;
1416 	case SRP_TSK_ABORT_TASK_SET:
1417 		return TMR_ABORT_TASK_SET;
1418 	case SRP_TSK_CLEAR_TASK_SET:
1419 		return TMR_CLEAR_TASK_SET;
1420 	case SRP_TSK_LUN_RESET:
1421 		return TMR_LUN_RESET;
1422 	case SRP_TSK_CLEAR_ACA:
1423 		return TMR_CLEAR_ACA;
1424 	default:
1425 		return -1;
1426 	}
1427 }
1428 
1429 /**
1430  * srpt_handle_tsk_mgmt() - Process an SRP_TSK_MGMT information unit.
1431  *
1432  * Returns 0 if and only if the request will be processed by the target core.
1433  *
1434  * For more information about SRP_TSK_MGMT information units, see also section
1435  * 6.7 in the SRP r16a document.
1436  */
1437 static void srpt_handle_tsk_mgmt(struct srpt_rdma_ch *ch,
1438 				 struct srpt_recv_ioctx *recv_ioctx,
1439 				 struct srpt_send_ioctx *send_ioctx)
1440 {
1441 	struct srp_tsk_mgmt *srp_tsk;
1442 	struct se_cmd *cmd;
1443 	struct se_session *sess = ch->sess;
1444 	int tcm_tmr;
1445 	int rc;
1446 
1447 	BUG_ON(!send_ioctx);
1448 
1449 	srp_tsk = recv_ioctx->ioctx.buf;
1450 	cmd = &send_ioctx->cmd;
1451 
1452 	pr_debug("recv tsk_mgmt fn %d for task_tag %lld and cmd tag %lld"
1453 		 " cm_id %p sess %p\n", srp_tsk->tsk_mgmt_func,
1454 		 srp_tsk->task_tag, srp_tsk->tag, ch->cm_id, ch->sess);
1455 
1456 	srpt_set_cmd_state(send_ioctx, SRPT_STATE_MGMT);
1457 	send_ioctx->cmd.tag = srp_tsk->tag;
1458 	tcm_tmr = srp_tmr_to_tcm(srp_tsk->tsk_mgmt_func);
1459 	rc = target_submit_tmr(&send_ioctx->cmd, sess, NULL,
1460 			       scsilun_to_int(&srp_tsk->lun), srp_tsk, tcm_tmr,
1461 			       GFP_KERNEL, srp_tsk->task_tag,
1462 			       TARGET_SCF_ACK_KREF);
1463 	if (rc != 0) {
1464 		send_ioctx->cmd.se_tmr_req->response = TMR_FUNCTION_REJECTED;
1465 		goto fail;
1466 	}
1467 	return;
1468 fail:
1469 	transport_send_check_condition_and_sense(cmd, 0, 0); // XXX:
1470 }
1471 
1472 /**
1473  * srpt_handle_new_iu() - Process a newly received information unit.
1474  * @ch:    RDMA channel through which the information unit has been received.
1475  * @ioctx: SRPT I/O context associated with the information unit.
1476  */
1477 static void srpt_handle_new_iu(struct srpt_rdma_ch *ch,
1478 			       struct srpt_recv_ioctx *recv_ioctx,
1479 			       struct srpt_send_ioctx *send_ioctx)
1480 {
1481 	struct srp_cmd *srp_cmd;
1482 
1483 	BUG_ON(!ch);
1484 	BUG_ON(!recv_ioctx);
1485 
1486 	ib_dma_sync_single_for_cpu(ch->sport->sdev->device,
1487 				   recv_ioctx->ioctx.dma, srp_max_req_size,
1488 				   DMA_FROM_DEVICE);
1489 
1490 	if (unlikely(ch->state == CH_CONNECTING))
1491 		goto out_wait;
1492 
1493 	if (unlikely(ch->state != CH_LIVE))
1494 		return;
1495 
1496 	srp_cmd = recv_ioctx->ioctx.buf;
1497 	if (srp_cmd->opcode == SRP_CMD || srp_cmd->opcode == SRP_TSK_MGMT) {
1498 		if (!send_ioctx) {
1499 			if (!list_empty(&ch->cmd_wait_list))
1500 				goto out_wait;
1501 			send_ioctx = srpt_get_send_ioctx(ch);
1502 		}
1503 		if (unlikely(!send_ioctx))
1504 			goto out_wait;
1505 	}
1506 
1507 	switch (srp_cmd->opcode) {
1508 	case SRP_CMD:
1509 		srpt_handle_cmd(ch, recv_ioctx, send_ioctx);
1510 		break;
1511 	case SRP_TSK_MGMT:
1512 		srpt_handle_tsk_mgmt(ch, recv_ioctx, send_ioctx);
1513 		break;
1514 	case SRP_I_LOGOUT:
1515 		pr_err("Not yet implemented: SRP_I_LOGOUT\n");
1516 		break;
1517 	case SRP_CRED_RSP:
1518 		pr_debug("received SRP_CRED_RSP\n");
1519 		break;
1520 	case SRP_AER_RSP:
1521 		pr_debug("received SRP_AER_RSP\n");
1522 		break;
1523 	case SRP_RSP:
1524 		pr_err("Received SRP_RSP\n");
1525 		break;
1526 	default:
1527 		pr_err("received IU with unknown opcode 0x%x\n",
1528 		       srp_cmd->opcode);
1529 		break;
1530 	}
1531 
1532 	srpt_post_recv(ch->sport->sdev, ch, recv_ioctx);
1533 	return;
1534 
1535 out_wait:
1536 	list_add_tail(&recv_ioctx->wait_list, &ch->cmd_wait_list);
1537 }
1538 
1539 static void srpt_recv_done(struct ib_cq *cq, struct ib_wc *wc)
1540 {
1541 	struct srpt_rdma_ch *ch = cq->cq_context;
1542 	struct srpt_recv_ioctx *ioctx =
1543 		container_of(wc->wr_cqe, struct srpt_recv_ioctx, ioctx.cqe);
1544 
1545 	if (wc->status == IB_WC_SUCCESS) {
1546 		int req_lim;
1547 
1548 		req_lim = atomic_dec_return(&ch->req_lim);
1549 		if (unlikely(req_lim < 0))
1550 			pr_err("req_lim = %d < 0\n", req_lim);
1551 		srpt_handle_new_iu(ch, ioctx, NULL);
1552 	} else {
1553 		pr_info("receiving failed for ioctx %p with status %d\n",
1554 			ioctx, wc->status);
1555 	}
1556 }
1557 
1558 /*
1559  * This function must be called from the context in which RDMA completions are
1560  * processed because it accesses the wait list without protection against
1561  * access from other threads.
1562  */
1563 static void srpt_process_wait_list(struct srpt_rdma_ch *ch)
1564 {
1565 	struct srpt_send_ioctx *ioctx;
1566 
1567 	while (!list_empty(&ch->cmd_wait_list) &&
1568 	       ch->state >= CH_LIVE &&
1569 	       (ioctx = srpt_get_send_ioctx(ch)) != NULL) {
1570 		struct srpt_recv_ioctx *recv_ioctx;
1571 
1572 		recv_ioctx = list_first_entry(&ch->cmd_wait_list,
1573 					      struct srpt_recv_ioctx,
1574 					      wait_list);
1575 		list_del(&recv_ioctx->wait_list);
1576 		srpt_handle_new_iu(ch, recv_ioctx, ioctx);
1577 	}
1578 }
1579 
1580 /**
1581  * Note: Although this has not yet been observed during tests, at least in
1582  * theory it is possible that the srpt_get_send_ioctx() call invoked by
1583  * srpt_handle_new_iu() fails. This is possible because the req_lim_delta
1584  * value in each response is set to one, and it is possible that this response
1585  * makes the initiator send a new request before the send completion for that
1586  * response has been processed. This could e.g. happen if the call to
1587  * srpt_put_send_iotcx() is delayed because of a higher priority interrupt or
1588  * if IB retransmission causes generation of the send completion to be
1589  * delayed. Incoming information units for which srpt_get_send_ioctx() fails
1590  * are queued on cmd_wait_list. The code below processes these delayed
1591  * requests one at a time.
1592  */
1593 static void srpt_send_done(struct ib_cq *cq, struct ib_wc *wc)
1594 {
1595 	struct srpt_rdma_ch *ch = cq->cq_context;
1596 	struct srpt_send_ioctx *ioctx =
1597 		container_of(wc->wr_cqe, struct srpt_send_ioctx, ioctx.cqe);
1598 	enum srpt_command_state state;
1599 
1600 	state = srpt_set_cmd_state(ioctx, SRPT_STATE_DONE);
1601 
1602 	WARN_ON(state != SRPT_STATE_CMD_RSP_SENT &&
1603 		state != SRPT_STATE_MGMT_RSP_SENT);
1604 
1605 	atomic_add(1 + ioctx->n_rdma, &ch->sq_wr_avail);
1606 
1607 	if (wc->status != IB_WC_SUCCESS)
1608 		pr_info("sending response for ioctx 0x%p failed"
1609 			" with status %d\n", ioctx, wc->status);
1610 
1611 	if (state != SRPT_STATE_DONE) {
1612 		transport_generic_free_cmd(&ioctx->cmd, 0);
1613 	} else {
1614 		pr_err("IB completion has been received too late for"
1615 		       " wr_id = %u.\n", ioctx->ioctx.index);
1616 	}
1617 
1618 	srpt_process_wait_list(ch);
1619 }
1620 
1621 /**
1622  * srpt_create_ch_ib() - Create receive and send completion queues.
1623  */
1624 static int srpt_create_ch_ib(struct srpt_rdma_ch *ch)
1625 {
1626 	struct ib_qp_init_attr *qp_init;
1627 	struct srpt_port *sport = ch->sport;
1628 	struct srpt_device *sdev = sport->sdev;
1629 	const struct ib_device_attr *attrs = &sdev->device->attrs;
1630 	u32 srp_sq_size = sport->port_attrib.srp_sq_size;
1631 	int i, ret;
1632 
1633 	WARN_ON(ch->rq_size < 1);
1634 
1635 	ret = -ENOMEM;
1636 	qp_init = kzalloc(sizeof(*qp_init), GFP_KERNEL);
1637 	if (!qp_init)
1638 		goto out;
1639 
1640 retry:
1641 	ch->cq = ib_alloc_cq(sdev->device, ch, ch->rq_size + srp_sq_size,
1642 			0 /* XXX: spread CQs */, IB_POLL_WORKQUEUE);
1643 	if (IS_ERR(ch->cq)) {
1644 		ret = PTR_ERR(ch->cq);
1645 		pr_err("failed to create CQ cqe= %d ret= %d\n",
1646 		       ch->rq_size + srp_sq_size, ret);
1647 		goto out;
1648 	}
1649 
1650 	qp_init->qp_context = (void *)ch;
1651 	qp_init->event_handler
1652 		= (void(*)(struct ib_event *, void*))srpt_qp_event;
1653 	qp_init->send_cq = ch->cq;
1654 	qp_init->recv_cq = ch->cq;
1655 	qp_init->sq_sig_type = IB_SIGNAL_REQ_WR;
1656 	qp_init->qp_type = IB_QPT_RC;
1657 	/*
1658 	 * We divide up our send queue size into half SEND WRs to send the
1659 	 * completions, and half R/W contexts to actually do the RDMA
1660 	 * READ/WRITE transfers.  Note that we need to allocate CQ slots for
1661 	 * both both, as RDMA contexts will also post completions for the
1662 	 * RDMA READ case.
1663 	 */
1664 	qp_init->cap.max_send_wr = min(srp_sq_size / 2, attrs->max_qp_wr + 0U);
1665 	qp_init->cap.max_rdma_ctxs = srp_sq_size / 2;
1666 	qp_init->cap.max_send_sge = min(attrs->max_sge, SRPT_MAX_SG_PER_WQE);
1667 	qp_init->port_num = ch->sport->port;
1668 	if (sdev->use_srq) {
1669 		qp_init->srq = sdev->srq;
1670 	} else {
1671 		qp_init->cap.max_recv_wr = ch->rq_size;
1672 		qp_init->cap.max_recv_sge = qp_init->cap.max_send_sge;
1673 	}
1674 
1675 	ch->qp = ib_create_qp(sdev->pd, qp_init);
1676 	if (IS_ERR(ch->qp)) {
1677 		ret = PTR_ERR(ch->qp);
1678 		if (ret == -ENOMEM) {
1679 			srp_sq_size /= 2;
1680 			if (srp_sq_size >= MIN_SRPT_SQ_SIZE) {
1681 				ib_destroy_cq(ch->cq);
1682 				goto retry;
1683 			}
1684 		}
1685 		pr_err("failed to create_qp ret= %d\n", ret);
1686 		goto err_destroy_cq;
1687 	}
1688 
1689 	atomic_set(&ch->sq_wr_avail, qp_init->cap.max_send_wr);
1690 
1691 	pr_debug("%s: max_cqe= %d max_sge= %d sq_size = %d cm_id= %p\n",
1692 		 __func__, ch->cq->cqe, qp_init->cap.max_send_sge,
1693 		 qp_init->cap.max_send_wr, ch->cm_id);
1694 
1695 	ret = srpt_init_ch_qp(ch, ch->qp);
1696 	if (ret)
1697 		goto err_destroy_qp;
1698 
1699 	if (!sdev->use_srq)
1700 		for (i = 0; i < ch->rq_size; i++)
1701 			srpt_post_recv(sdev, ch, ch->ioctx_recv_ring[i]);
1702 
1703 out:
1704 	kfree(qp_init);
1705 	return ret;
1706 
1707 err_destroy_qp:
1708 	ib_destroy_qp(ch->qp);
1709 err_destroy_cq:
1710 	ib_free_cq(ch->cq);
1711 	goto out;
1712 }
1713 
1714 static void srpt_destroy_ch_ib(struct srpt_rdma_ch *ch)
1715 {
1716 	ib_destroy_qp(ch->qp);
1717 	ib_free_cq(ch->cq);
1718 }
1719 
1720 /**
1721  * srpt_close_ch() - Close an RDMA channel.
1722  *
1723  * Make sure all resources associated with the channel will be deallocated at
1724  * an appropriate time.
1725  *
1726  * Returns true if and only if the channel state has been modified into
1727  * CH_DRAINING.
1728  */
1729 static bool srpt_close_ch(struct srpt_rdma_ch *ch)
1730 {
1731 	int ret;
1732 
1733 	if (!srpt_set_ch_state(ch, CH_DRAINING)) {
1734 		pr_debug("%s-%d: already closed\n", ch->sess_name,
1735 			 ch->qp->qp_num);
1736 		return false;
1737 	}
1738 
1739 	kref_get(&ch->kref);
1740 
1741 	ret = srpt_ch_qp_err(ch);
1742 	if (ret < 0)
1743 		pr_err("%s-%d: changing queue pair into error state failed: %d\n",
1744 		       ch->sess_name, ch->qp->qp_num, ret);
1745 
1746 	pr_debug("%s-%d: queued zerolength write\n", ch->sess_name,
1747 		 ch->qp->qp_num);
1748 	ret = srpt_zerolength_write(ch);
1749 	if (ret < 0) {
1750 		pr_err("%s-%d: queuing zero-length write failed: %d\n",
1751 		       ch->sess_name, ch->qp->qp_num, ret);
1752 		if (srpt_set_ch_state(ch, CH_DISCONNECTED))
1753 			schedule_work(&ch->release_work);
1754 		else
1755 			WARN_ON_ONCE(true);
1756 	}
1757 
1758 	kref_put(&ch->kref, srpt_free_ch);
1759 
1760 	return true;
1761 }
1762 
1763 /*
1764  * Change the channel state into CH_DISCONNECTING. If a channel has not yet
1765  * reached the connected state, close it. If a channel is in the connected
1766  * state, send a DREQ. If a DREQ has been received, send a DREP. Note: it is
1767  * the responsibility of the caller to ensure that this function is not
1768  * invoked concurrently with the code that accepts a connection. This means
1769  * that this function must either be invoked from inside a CM callback
1770  * function or that it must be invoked with the srpt_port.mutex held.
1771  */
1772 static int srpt_disconnect_ch(struct srpt_rdma_ch *ch)
1773 {
1774 	int ret;
1775 
1776 	if (!srpt_set_ch_state(ch, CH_DISCONNECTING))
1777 		return -ENOTCONN;
1778 
1779 	ret = ib_send_cm_dreq(ch->cm_id, NULL, 0);
1780 	if (ret < 0)
1781 		ret = ib_send_cm_drep(ch->cm_id, NULL, 0);
1782 
1783 	if (ret < 0 && srpt_close_ch(ch))
1784 		ret = 0;
1785 
1786 	return ret;
1787 }
1788 
1789 /*
1790  * Send DREQ and wait for DREP. Return true if and only if this function
1791  * changed the state of @ch.
1792  */
1793 static bool srpt_disconnect_ch_sync(struct srpt_rdma_ch *ch)
1794 	__must_hold(&sdev->mutex)
1795 {
1796 	DECLARE_COMPLETION_ONSTACK(release_done);
1797 	struct srpt_device *sdev = ch->sport->sdev;
1798 	bool wait;
1799 
1800 	lockdep_assert_held(&sdev->mutex);
1801 
1802 	pr_debug("ch %s-%d state %d\n", ch->sess_name, ch->qp->qp_num,
1803 		 ch->state);
1804 
1805 	WARN_ON(ch->release_done);
1806 	ch->release_done = &release_done;
1807 	wait = !list_empty(&ch->list);
1808 	srpt_disconnect_ch(ch);
1809 	mutex_unlock(&sdev->mutex);
1810 
1811 	if (!wait)
1812 		goto out;
1813 
1814 	while (wait_for_completion_timeout(&release_done, 180 * HZ) == 0)
1815 		pr_info("%s(%s-%d state %d): still waiting ...\n", __func__,
1816 			ch->sess_name, ch->qp->qp_num, ch->state);
1817 
1818 out:
1819 	mutex_lock(&sdev->mutex);
1820 	return wait;
1821 }
1822 
1823 static void srpt_set_enabled(struct srpt_port *sport, bool enabled)
1824 	__must_hold(&sdev->mutex)
1825 {
1826 	struct srpt_device *sdev = sport->sdev;
1827 	struct srpt_rdma_ch *ch;
1828 
1829 	lockdep_assert_held(&sdev->mutex);
1830 
1831 	if (sport->enabled == enabled)
1832 		return;
1833 	sport->enabled = enabled;
1834 	if (sport->enabled)
1835 		return;
1836 
1837 again:
1838 	list_for_each_entry(ch, &sdev->rch_list, list) {
1839 		if (ch->sport == sport) {
1840 			pr_info("%s: closing channel %s-%d\n",
1841 				sdev->device->name, ch->sess_name,
1842 				ch->qp->qp_num);
1843 			if (srpt_disconnect_ch_sync(ch))
1844 				goto again;
1845 		}
1846 	}
1847 
1848 }
1849 
1850 static void srpt_free_ch(struct kref *kref)
1851 {
1852 	struct srpt_rdma_ch *ch = container_of(kref, struct srpt_rdma_ch, kref);
1853 
1854 	kfree(ch);
1855 }
1856 
1857 static void srpt_release_channel_work(struct work_struct *w)
1858 {
1859 	struct srpt_rdma_ch *ch;
1860 	struct srpt_device *sdev;
1861 	struct se_session *se_sess;
1862 
1863 	ch = container_of(w, struct srpt_rdma_ch, release_work);
1864 	pr_debug("%s: %s-%d; release_done = %p\n", __func__, ch->sess_name,
1865 		 ch->qp->qp_num, ch->release_done);
1866 
1867 	sdev = ch->sport->sdev;
1868 	BUG_ON(!sdev);
1869 
1870 	se_sess = ch->sess;
1871 	BUG_ON(!se_sess);
1872 
1873 	target_sess_cmd_list_set_waiting(se_sess);
1874 	target_wait_for_sess_cmds(se_sess);
1875 
1876 	transport_deregister_session_configfs(se_sess);
1877 	transport_deregister_session(se_sess);
1878 	ch->sess = NULL;
1879 
1880 	ib_destroy_cm_id(ch->cm_id);
1881 
1882 	srpt_destroy_ch_ib(ch);
1883 
1884 	srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_ring,
1885 			     ch->sport->sdev, ch->rq_size,
1886 			     ch->rsp_size, DMA_TO_DEVICE);
1887 
1888 	srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_recv_ring,
1889 			     sdev, ch->rq_size,
1890 			     srp_max_req_size, DMA_FROM_DEVICE);
1891 
1892 	mutex_lock(&sdev->mutex);
1893 	list_del_init(&ch->list);
1894 	if (ch->release_done)
1895 		complete(ch->release_done);
1896 	mutex_unlock(&sdev->mutex);
1897 
1898 	wake_up(&sdev->ch_releaseQ);
1899 
1900 	kref_put(&ch->kref, srpt_free_ch);
1901 }
1902 
1903 /**
1904  * srpt_cm_req_recv() - Process the event IB_CM_REQ_RECEIVED.
1905  *
1906  * Ownership of the cm_id is transferred to the target session if this
1907  * functions returns zero. Otherwise the caller remains the owner of cm_id.
1908  */
1909 static int srpt_cm_req_recv(struct ib_cm_id *cm_id,
1910 			    struct ib_cm_req_event_param *param,
1911 			    void *private_data)
1912 {
1913 	struct srpt_device *sdev = cm_id->context;
1914 	struct srpt_port *sport = &sdev->port[param->port - 1];
1915 	struct srp_login_req *req;
1916 	struct srp_login_rsp *rsp;
1917 	struct srp_login_rej *rej;
1918 	struct ib_cm_rep_param *rep_param;
1919 	struct srpt_rdma_ch *ch, *tmp_ch;
1920 	__be16 *guid;
1921 	u32 it_iu_len;
1922 	int i, ret = 0;
1923 
1924 	WARN_ON_ONCE(irqs_disabled());
1925 
1926 	if (WARN_ON(!sdev || !private_data))
1927 		return -EINVAL;
1928 
1929 	req = (struct srp_login_req *)private_data;
1930 
1931 	it_iu_len = be32_to_cpu(req->req_it_iu_len);
1932 
1933 	pr_info("Received SRP_LOGIN_REQ with i_port_id 0x%llx:0x%llx,"
1934 		" t_port_id 0x%llx:0x%llx and it_iu_len %d on port %d"
1935 		" (guid=0x%llx:0x%llx)\n",
1936 		be64_to_cpu(*(__be64 *)&req->initiator_port_id[0]),
1937 		be64_to_cpu(*(__be64 *)&req->initiator_port_id[8]),
1938 		be64_to_cpu(*(__be64 *)&req->target_port_id[0]),
1939 		be64_to_cpu(*(__be64 *)&req->target_port_id[8]),
1940 		it_iu_len,
1941 		param->port,
1942 		be64_to_cpu(*(__be64 *)&sdev->port[param->port - 1].gid.raw[0]),
1943 		be64_to_cpu(*(__be64 *)&sdev->port[param->port - 1].gid.raw[8]));
1944 
1945 	rsp = kzalloc(sizeof(*rsp), GFP_KERNEL);
1946 	rej = kzalloc(sizeof(*rej), GFP_KERNEL);
1947 	rep_param = kzalloc(sizeof(*rep_param), GFP_KERNEL);
1948 
1949 	if (!rsp || !rej || !rep_param) {
1950 		ret = -ENOMEM;
1951 		goto out;
1952 	}
1953 
1954 	if (it_iu_len > srp_max_req_size || it_iu_len < 64) {
1955 		rej->reason = cpu_to_be32(
1956 			      SRP_LOGIN_REJ_REQ_IT_IU_LENGTH_TOO_LARGE);
1957 		ret = -EINVAL;
1958 		pr_err("rejected SRP_LOGIN_REQ because its"
1959 		       " length (%d bytes) is out of range (%d .. %d)\n",
1960 		       it_iu_len, 64, srp_max_req_size);
1961 		goto reject;
1962 	}
1963 
1964 	if (!sport->enabled) {
1965 		rej->reason = cpu_to_be32(
1966 			      SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
1967 		ret = -EINVAL;
1968 		pr_err("rejected SRP_LOGIN_REQ because the target port"
1969 		       " has not yet been enabled\n");
1970 		goto reject;
1971 	}
1972 
1973 	if ((req->req_flags & SRP_MTCH_ACTION) == SRP_MULTICHAN_SINGLE) {
1974 		rsp->rsp_flags = SRP_LOGIN_RSP_MULTICHAN_NO_CHAN;
1975 
1976 		mutex_lock(&sdev->mutex);
1977 
1978 		list_for_each_entry_safe(ch, tmp_ch, &sdev->rch_list, list) {
1979 			if (!memcmp(ch->i_port_id, req->initiator_port_id, 16)
1980 			    && !memcmp(ch->t_port_id, req->target_port_id, 16)
1981 			    && param->port == ch->sport->port
1982 			    && param->listen_id == ch->sport->sdev->cm_id
1983 			    && ch->cm_id) {
1984 				if (srpt_disconnect_ch(ch) < 0)
1985 					continue;
1986 				pr_info("Relogin - closed existing channel %s\n",
1987 					ch->sess_name);
1988 				rsp->rsp_flags =
1989 					SRP_LOGIN_RSP_MULTICHAN_TERMINATED;
1990 			}
1991 		}
1992 
1993 		mutex_unlock(&sdev->mutex);
1994 
1995 	} else
1996 		rsp->rsp_flags = SRP_LOGIN_RSP_MULTICHAN_MAINTAINED;
1997 
1998 	if (*(__be64 *)req->target_port_id != cpu_to_be64(srpt_service_guid)
1999 	    || *(__be64 *)(req->target_port_id + 8) !=
2000 	       cpu_to_be64(srpt_service_guid)) {
2001 		rej->reason = cpu_to_be32(
2002 			      SRP_LOGIN_REJ_UNABLE_ASSOCIATE_CHANNEL);
2003 		ret = -ENOMEM;
2004 		pr_err("rejected SRP_LOGIN_REQ because it"
2005 		       " has an invalid target port identifier.\n");
2006 		goto reject;
2007 	}
2008 
2009 	ch = kzalloc(sizeof(*ch), GFP_KERNEL);
2010 	if (!ch) {
2011 		rej->reason = cpu_to_be32(
2012 			      SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
2013 		pr_err("rejected SRP_LOGIN_REQ because no memory.\n");
2014 		ret = -ENOMEM;
2015 		goto reject;
2016 	}
2017 
2018 	kref_init(&ch->kref);
2019 	ch->zw_cqe.done = srpt_zerolength_write_done;
2020 	INIT_WORK(&ch->release_work, srpt_release_channel_work);
2021 	memcpy(ch->i_port_id, req->initiator_port_id, 16);
2022 	memcpy(ch->t_port_id, req->target_port_id, 16);
2023 	ch->sport = &sdev->port[param->port - 1];
2024 	ch->cm_id = cm_id;
2025 	cm_id->context = ch;
2026 	/*
2027 	 * ch->rq_size should be at least as large as the initiator queue
2028 	 * depth to avoid that the initiator driver has to report QUEUE_FULL
2029 	 * to the SCSI mid-layer.
2030 	 */
2031 	ch->rq_size = min(SRPT_RQ_SIZE, sdev->device->attrs.max_qp_wr);
2032 	spin_lock_init(&ch->spinlock);
2033 	ch->state = CH_CONNECTING;
2034 	INIT_LIST_HEAD(&ch->cmd_wait_list);
2035 	ch->rsp_size = ch->sport->port_attrib.srp_max_rsp_size;
2036 
2037 	ch->ioctx_ring = (struct srpt_send_ioctx **)
2038 		srpt_alloc_ioctx_ring(ch->sport->sdev, ch->rq_size,
2039 				      sizeof(*ch->ioctx_ring[0]),
2040 				      ch->rsp_size, DMA_TO_DEVICE);
2041 	if (!ch->ioctx_ring)
2042 		goto free_ch;
2043 
2044 	INIT_LIST_HEAD(&ch->free_list);
2045 	for (i = 0; i < ch->rq_size; i++) {
2046 		ch->ioctx_ring[i]->ch = ch;
2047 		list_add_tail(&ch->ioctx_ring[i]->free_list, &ch->free_list);
2048 	}
2049 	if (!sdev->use_srq) {
2050 		ch->ioctx_recv_ring = (struct srpt_recv_ioctx **)
2051 			srpt_alloc_ioctx_ring(ch->sport->sdev, ch->rq_size,
2052 					      sizeof(*ch->ioctx_recv_ring[0]),
2053 					      srp_max_req_size,
2054 					      DMA_FROM_DEVICE);
2055 		if (!ch->ioctx_recv_ring) {
2056 			pr_err("rejected SRP_LOGIN_REQ because creating a new QP RQ ring failed.\n");
2057 			rej->reason =
2058 			    cpu_to_be32(SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
2059 			goto free_ring;
2060 		}
2061 	}
2062 
2063 	ret = srpt_create_ch_ib(ch);
2064 	if (ret) {
2065 		rej->reason = cpu_to_be32(
2066 			      SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
2067 		pr_err("rejected SRP_LOGIN_REQ because creating"
2068 		       " a new RDMA channel failed.\n");
2069 		goto free_recv_ring;
2070 	}
2071 
2072 	ret = srpt_ch_qp_rtr(ch, ch->qp);
2073 	if (ret) {
2074 		rej->reason = cpu_to_be32(SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
2075 		pr_err("rejected SRP_LOGIN_REQ because enabling"
2076 		       " RTR failed (error code = %d)\n", ret);
2077 		goto destroy_ib;
2078 	}
2079 
2080 	guid = (__be16 *)&param->primary_path->dgid.global.interface_id;
2081 	snprintf(ch->ini_guid, sizeof(ch->ini_guid), "%04x:%04x:%04x:%04x",
2082 		 be16_to_cpu(guid[0]), be16_to_cpu(guid[1]),
2083 		 be16_to_cpu(guid[2]), be16_to_cpu(guid[3]));
2084 	snprintf(ch->sess_name, sizeof(ch->sess_name), "0x%016llx%016llx",
2085 			be64_to_cpu(*(__be64 *)ch->i_port_id),
2086 			be64_to_cpu(*(__be64 *)(ch->i_port_id + 8)));
2087 
2088 	pr_debug("registering session %s\n", ch->sess_name);
2089 
2090 	if (sport->port_guid_tpg.se_tpg_wwn)
2091 		ch->sess = target_alloc_session(&sport->port_guid_tpg, 0, 0,
2092 						TARGET_PROT_NORMAL,
2093 						ch->ini_guid, ch, NULL);
2094 	if (sport->port_gid_tpg.se_tpg_wwn && IS_ERR_OR_NULL(ch->sess))
2095 		ch->sess = target_alloc_session(&sport->port_gid_tpg, 0, 0,
2096 					TARGET_PROT_NORMAL, ch->sess_name, ch,
2097 					NULL);
2098 	/* Retry without leading "0x" */
2099 	if (sport->port_gid_tpg.se_tpg_wwn && IS_ERR_OR_NULL(ch->sess))
2100 		ch->sess = target_alloc_session(&sport->port_gid_tpg, 0, 0,
2101 						TARGET_PROT_NORMAL,
2102 						ch->sess_name + 2, ch, NULL);
2103 	if (IS_ERR_OR_NULL(ch->sess)) {
2104 		pr_info("Rejected login because no ACL has been configured yet for initiator %s.\n",
2105 			ch->sess_name);
2106 		rej->reason = cpu_to_be32((PTR_ERR(ch->sess) == -ENOMEM) ?
2107 				SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES :
2108 				SRP_LOGIN_REJ_CHANNEL_LIMIT_REACHED);
2109 		goto destroy_ib;
2110 	}
2111 
2112 	pr_debug("Establish connection sess=%p name=%s cm_id=%p\n", ch->sess,
2113 		 ch->sess_name, ch->cm_id);
2114 
2115 	/* create srp_login_response */
2116 	rsp->opcode = SRP_LOGIN_RSP;
2117 	rsp->tag = req->tag;
2118 	rsp->max_it_iu_len = req->req_it_iu_len;
2119 	rsp->max_ti_iu_len = req->req_it_iu_len;
2120 	ch->max_ti_iu_len = it_iu_len;
2121 	rsp->buf_fmt = cpu_to_be16(SRP_BUF_FORMAT_DIRECT
2122 				   | SRP_BUF_FORMAT_INDIRECT);
2123 	rsp->req_lim_delta = cpu_to_be32(ch->rq_size);
2124 	atomic_set(&ch->req_lim, ch->rq_size);
2125 	atomic_set(&ch->req_lim_delta, 0);
2126 
2127 	/* create cm reply */
2128 	rep_param->qp_num = ch->qp->qp_num;
2129 	rep_param->private_data = (void *)rsp;
2130 	rep_param->private_data_len = sizeof(*rsp);
2131 	rep_param->rnr_retry_count = 7;
2132 	rep_param->flow_control = 1;
2133 	rep_param->failover_accepted = 0;
2134 	rep_param->srq = 1;
2135 	rep_param->responder_resources = 4;
2136 	rep_param->initiator_depth = 4;
2137 
2138 	ret = ib_send_cm_rep(cm_id, rep_param);
2139 	if (ret) {
2140 		pr_err("sending SRP_LOGIN_REQ response failed"
2141 		       " (error code = %d)\n", ret);
2142 		goto release_channel;
2143 	}
2144 
2145 	mutex_lock(&sdev->mutex);
2146 	list_add_tail(&ch->list, &sdev->rch_list);
2147 	mutex_unlock(&sdev->mutex);
2148 
2149 	goto out;
2150 
2151 release_channel:
2152 	srpt_disconnect_ch(ch);
2153 	transport_deregister_session_configfs(ch->sess);
2154 	transport_deregister_session(ch->sess);
2155 	ch->sess = NULL;
2156 
2157 destroy_ib:
2158 	srpt_destroy_ch_ib(ch);
2159 
2160 free_recv_ring:
2161 	srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_recv_ring,
2162 			     ch->sport->sdev, ch->rq_size,
2163 			     srp_max_req_size, DMA_FROM_DEVICE);
2164 
2165 free_ring:
2166 	srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_ring,
2167 			     ch->sport->sdev, ch->rq_size,
2168 			     ch->rsp_size, DMA_TO_DEVICE);
2169 free_ch:
2170 	kfree(ch);
2171 
2172 reject:
2173 	rej->opcode = SRP_LOGIN_REJ;
2174 	rej->tag = req->tag;
2175 	rej->buf_fmt = cpu_to_be16(SRP_BUF_FORMAT_DIRECT
2176 				   | SRP_BUF_FORMAT_INDIRECT);
2177 
2178 	ib_send_cm_rej(cm_id, IB_CM_REJ_CONSUMER_DEFINED, NULL, 0,
2179 			     (void *)rej, sizeof(*rej));
2180 
2181 out:
2182 	kfree(rep_param);
2183 	kfree(rsp);
2184 	kfree(rej);
2185 
2186 	return ret;
2187 }
2188 
2189 static void srpt_cm_rej_recv(struct srpt_rdma_ch *ch,
2190 			     enum ib_cm_rej_reason reason,
2191 			     const u8 *private_data,
2192 			     u8 private_data_len)
2193 {
2194 	char *priv = NULL;
2195 	int i;
2196 
2197 	if (private_data_len && (priv = kmalloc(private_data_len * 3 + 1,
2198 						GFP_KERNEL))) {
2199 		for (i = 0; i < private_data_len; i++)
2200 			sprintf(priv + 3 * i, " %02x", private_data[i]);
2201 	}
2202 	pr_info("Received CM REJ for ch %s-%d; reason %d%s%s.\n",
2203 		ch->sess_name, ch->qp->qp_num, reason, private_data_len ?
2204 		"; private data" : "", priv ? priv : " (?)");
2205 	kfree(priv);
2206 }
2207 
2208 /**
2209  * srpt_cm_rtu_recv() - Process an IB_CM_RTU_RECEIVED or USER_ESTABLISHED event.
2210  *
2211  * An IB_CM_RTU_RECEIVED message indicates that the connection is established
2212  * and that the recipient may begin transmitting (RTU = ready to use).
2213  */
2214 static void srpt_cm_rtu_recv(struct srpt_rdma_ch *ch)
2215 {
2216 	int ret;
2217 
2218 	if (srpt_set_ch_state(ch, CH_LIVE)) {
2219 		ret = srpt_ch_qp_rts(ch, ch->qp);
2220 
2221 		if (ret == 0) {
2222 			/* Trigger wait list processing. */
2223 			ret = srpt_zerolength_write(ch);
2224 			WARN_ONCE(ret < 0, "%d\n", ret);
2225 		} else {
2226 			srpt_close_ch(ch);
2227 		}
2228 	}
2229 }
2230 
2231 /**
2232  * srpt_cm_handler() - IB connection manager callback function.
2233  *
2234  * A non-zero return value will cause the caller destroy the CM ID.
2235  *
2236  * Note: srpt_cm_handler() must only return a non-zero value when transferring
2237  * ownership of the cm_id to a channel by srpt_cm_req_recv() failed. Returning
2238  * a non-zero value in any other case will trigger a race with the
2239  * ib_destroy_cm_id() call in srpt_release_channel().
2240  */
2241 static int srpt_cm_handler(struct ib_cm_id *cm_id, struct ib_cm_event *event)
2242 {
2243 	struct srpt_rdma_ch *ch = cm_id->context;
2244 	int ret;
2245 
2246 	ret = 0;
2247 	switch (event->event) {
2248 	case IB_CM_REQ_RECEIVED:
2249 		ret = srpt_cm_req_recv(cm_id, &event->param.req_rcvd,
2250 				       event->private_data);
2251 		break;
2252 	case IB_CM_REJ_RECEIVED:
2253 		srpt_cm_rej_recv(ch, event->param.rej_rcvd.reason,
2254 				 event->private_data,
2255 				 IB_CM_REJ_PRIVATE_DATA_SIZE);
2256 		break;
2257 	case IB_CM_RTU_RECEIVED:
2258 	case IB_CM_USER_ESTABLISHED:
2259 		srpt_cm_rtu_recv(ch);
2260 		break;
2261 	case IB_CM_DREQ_RECEIVED:
2262 		srpt_disconnect_ch(ch);
2263 		break;
2264 	case IB_CM_DREP_RECEIVED:
2265 		pr_info("Received CM DREP message for ch %s-%d.\n",
2266 			ch->sess_name, ch->qp->qp_num);
2267 		srpt_close_ch(ch);
2268 		break;
2269 	case IB_CM_TIMEWAIT_EXIT:
2270 		pr_info("Received CM TimeWait exit for ch %s-%d.\n",
2271 			ch->sess_name, ch->qp->qp_num);
2272 		srpt_close_ch(ch);
2273 		break;
2274 	case IB_CM_REP_ERROR:
2275 		pr_info("Received CM REP error for ch %s-%d.\n", ch->sess_name,
2276 			ch->qp->qp_num);
2277 		break;
2278 	case IB_CM_DREQ_ERROR:
2279 		pr_info("Received CM DREQ ERROR event.\n");
2280 		break;
2281 	case IB_CM_MRA_RECEIVED:
2282 		pr_info("Received CM MRA event\n");
2283 		break;
2284 	default:
2285 		pr_err("received unrecognized CM event %d\n", event->event);
2286 		break;
2287 	}
2288 
2289 	return ret;
2290 }
2291 
2292 static int srpt_write_pending_status(struct se_cmd *se_cmd)
2293 {
2294 	struct srpt_send_ioctx *ioctx;
2295 
2296 	ioctx = container_of(se_cmd, struct srpt_send_ioctx, cmd);
2297 	return srpt_get_cmd_state(ioctx) == SRPT_STATE_NEED_DATA;
2298 }
2299 
2300 /*
2301  * srpt_write_pending() - Start data transfer from initiator to target (write).
2302  */
2303 static int srpt_write_pending(struct se_cmd *se_cmd)
2304 {
2305 	struct srpt_send_ioctx *ioctx =
2306 		container_of(se_cmd, struct srpt_send_ioctx, cmd);
2307 	struct srpt_rdma_ch *ch = ioctx->ch;
2308 	struct ib_send_wr *first_wr = NULL, *bad_wr;
2309 	struct ib_cqe *cqe = &ioctx->rdma_cqe;
2310 	enum srpt_command_state new_state;
2311 	int ret, i;
2312 
2313 	new_state = srpt_set_cmd_state(ioctx, SRPT_STATE_NEED_DATA);
2314 	WARN_ON(new_state == SRPT_STATE_DONE);
2315 
2316 	if (atomic_sub_return(ioctx->n_rdma, &ch->sq_wr_avail) < 0) {
2317 		pr_warn("%s: IB send queue full (needed %d)\n",
2318 				__func__, ioctx->n_rdma);
2319 		ret = -ENOMEM;
2320 		goto out_undo;
2321 	}
2322 
2323 	cqe->done = srpt_rdma_read_done;
2324 	for (i = ioctx->n_rw_ctx - 1; i >= 0; i--) {
2325 		struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
2326 
2327 		first_wr = rdma_rw_ctx_wrs(&ctx->rw, ch->qp, ch->sport->port,
2328 				cqe, first_wr);
2329 		cqe = NULL;
2330 	}
2331 
2332 	ret = ib_post_send(ch->qp, first_wr, &bad_wr);
2333 	if (ret) {
2334 		pr_err("%s: ib_post_send() returned %d for %d (avail: %d)\n",
2335 			 __func__, ret, ioctx->n_rdma,
2336 			 atomic_read(&ch->sq_wr_avail));
2337 		goto out_undo;
2338 	}
2339 
2340 	return 0;
2341 out_undo:
2342 	atomic_add(ioctx->n_rdma, &ch->sq_wr_avail);
2343 	return ret;
2344 }
2345 
2346 static u8 tcm_to_srp_tsk_mgmt_status(const int tcm_mgmt_status)
2347 {
2348 	switch (tcm_mgmt_status) {
2349 	case TMR_FUNCTION_COMPLETE:
2350 		return SRP_TSK_MGMT_SUCCESS;
2351 	case TMR_FUNCTION_REJECTED:
2352 		return SRP_TSK_MGMT_FUNC_NOT_SUPP;
2353 	}
2354 	return SRP_TSK_MGMT_FAILED;
2355 }
2356 
2357 /**
2358  * srpt_queue_response() - Transmits the response to a SCSI command.
2359  *
2360  * Callback function called by the TCM core. Must not block since it can be
2361  * invoked on the context of the IB completion handler.
2362  */
2363 static void srpt_queue_response(struct se_cmd *cmd)
2364 {
2365 	struct srpt_send_ioctx *ioctx =
2366 		container_of(cmd, struct srpt_send_ioctx, cmd);
2367 	struct srpt_rdma_ch *ch = ioctx->ch;
2368 	struct srpt_device *sdev = ch->sport->sdev;
2369 	struct ib_send_wr send_wr, *first_wr = &send_wr, *bad_wr;
2370 	struct ib_sge sge;
2371 	enum srpt_command_state state;
2372 	unsigned long flags;
2373 	int resp_len, ret, i;
2374 	u8 srp_tm_status;
2375 
2376 	BUG_ON(!ch);
2377 
2378 	spin_lock_irqsave(&ioctx->spinlock, flags);
2379 	state = ioctx->state;
2380 	switch (state) {
2381 	case SRPT_STATE_NEW:
2382 	case SRPT_STATE_DATA_IN:
2383 		ioctx->state = SRPT_STATE_CMD_RSP_SENT;
2384 		break;
2385 	case SRPT_STATE_MGMT:
2386 		ioctx->state = SRPT_STATE_MGMT_RSP_SENT;
2387 		break;
2388 	default:
2389 		WARN(true, "ch %p; cmd %d: unexpected command state %d\n",
2390 			ch, ioctx->ioctx.index, ioctx->state);
2391 		break;
2392 	}
2393 	spin_unlock_irqrestore(&ioctx->spinlock, flags);
2394 
2395 	if (unlikely(WARN_ON_ONCE(state == SRPT_STATE_CMD_RSP_SENT)))
2396 		return;
2397 
2398 	/* For read commands, transfer the data to the initiator. */
2399 	if (ioctx->cmd.data_direction == DMA_FROM_DEVICE &&
2400 	    ioctx->cmd.data_length &&
2401 	    !ioctx->queue_status_only) {
2402 		for (i = ioctx->n_rw_ctx - 1; i >= 0; i--) {
2403 			struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
2404 
2405 			first_wr = rdma_rw_ctx_wrs(&ctx->rw, ch->qp,
2406 					ch->sport->port, NULL, first_wr);
2407 		}
2408 	}
2409 
2410 	if (state != SRPT_STATE_MGMT)
2411 		resp_len = srpt_build_cmd_rsp(ch, ioctx, ioctx->cmd.tag,
2412 					      cmd->scsi_status);
2413 	else {
2414 		srp_tm_status
2415 			= tcm_to_srp_tsk_mgmt_status(cmd->se_tmr_req->response);
2416 		resp_len = srpt_build_tskmgmt_rsp(ch, ioctx, srp_tm_status,
2417 						 ioctx->cmd.tag);
2418 	}
2419 
2420 	atomic_inc(&ch->req_lim);
2421 
2422 	if (unlikely(atomic_sub_return(1 + ioctx->n_rdma,
2423 			&ch->sq_wr_avail) < 0)) {
2424 		pr_warn("%s: IB send queue full (needed %d)\n",
2425 				__func__, ioctx->n_rdma);
2426 		ret = -ENOMEM;
2427 		goto out;
2428 	}
2429 
2430 	ib_dma_sync_single_for_device(sdev->device, ioctx->ioctx.dma, resp_len,
2431 				      DMA_TO_DEVICE);
2432 
2433 	sge.addr = ioctx->ioctx.dma;
2434 	sge.length = resp_len;
2435 	sge.lkey = sdev->lkey;
2436 
2437 	ioctx->ioctx.cqe.done = srpt_send_done;
2438 	send_wr.next = NULL;
2439 	send_wr.wr_cqe = &ioctx->ioctx.cqe;
2440 	send_wr.sg_list = &sge;
2441 	send_wr.num_sge = 1;
2442 	send_wr.opcode = IB_WR_SEND;
2443 	send_wr.send_flags = IB_SEND_SIGNALED;
2444 
2445 	ret = ib_post_send(ch->qp, first_wr, &bad_wr);
2446 	if (ret < 0) {
2447 		pr_err("%s: sending cmd response failed for tag %llu (%d)\n",
2448 			__func__, ioctx->cmd.tag, ret);
2449 		goto out;
2450 	}
2451 
2452 	return;
2453 
2454 out:
2455 	atomic_add(1 + ioctx->n_rdma, &ch->sq_wr_avail);
2456 	atomic_dec(&ch->req_lim);
2457 	srpt_set_cmd_state(ioctx, SRPT_STATE_DONE);
2458 	target_put_sess_cmd(&ioctx->cmd);
2459 }
2460 
2461 static int srpt_queue_data_in(struct se_cmd *cmd)
2462 {
2463 	srpt_queue_response(cmd);
2464 	return 0;
2465 }
2466 
2467 static void srpt_queue_tm_rsp(struct se_cmd *cmd)
2468 {
2469 	srpt_queue_response(cmd);
2470 }
2471 
2472 static void srpt_aborted_task(struct se_cmd *cmd)
2473 {
2474 }
2475 
2476 static int srpt_queue_status(struct se_cmd *cmd)
2477 {
2478 	struct srpt_send_ioctx *ioctx;
2479 
2480 	ioctx = container_of(cmd, struct srpt_send_ioctx, cmd);
2481 	BUG_ON(ioctx->sense_data != cmd->sense_buffer);
2482 	if (cmd->se_cmd_flags &
2483 	    (SCF_TRANSPORT_TASK_SENSE | SCF_EMULATED_TASK_SENSE))
2484 		WARN_ON(cmd->scsi_status != SAM_STAT_CHECK_CONDITION);
2485 	ioctx->queue_status_only = true;
2486 	srpt_queue_response(cmd);
2487 	return 0;
2488 }
2489 
2490 static void srpt_refresh_port_work(struct work_struct *work)
2491 {
2492 	struct srpt_port *sport = container_of(work, struct srpt_port, work);
2493 
2494 	srpt_refresh_port(sport);
2495 }
2496 
2497 /**
2498  * srpt_release_sdev() - Free the channel resources associated with a target.
2499  */
2500 static int srpt_release_sdev(struct srpt_device *sdev)
2501 {
2502 	int i, res;
2503 
2504 	WARN_ON_ONCE(irqs_disabled());
2505 
2506 	BUG_ON(!sdev);
2507 
2508 	mutex_lock(&sdev->mutex);
2509 	for (i = 0; i < ARRAY_SIZE(sdev->port); i++)
2510 		srpt_set_enabled(&sdev->port[i], false);
2511 	mutex_unlock(&sdev->mutex);
2512 
2513 	res = wait_event_interruptible(sdev->ch_releaseQ,
2514 				       list_empty_careful(&sdev->rch_list));
2515 	if (res)
2516 		pr_err("%s: interrupted.\n", __func__);
2517 
2518 	return 0;
2519 }
2520 
2521 static struct se_wwn *__srpt_lookup_wwn(const char *name)
2522 {
2523 	struct ib_device *dev;
2524 	struct srpt_device *sdev;
2525 	struct srpt_port *sport;
2526 	int i;
2527 
2528 	list_for_each_entry(sdev, &srpt_dev_list, list) {
2529 		dev = sdev->device;
2530 		if (!dev)
2531 			continue;
2532 
2533 		for (i = 0; i < dev->phys_port_cnt; i++) {
2534 			sport = &sdev->port[i];
2535 
2536 			if (strcmp(sport->port_guid, name) == 0)
2537 				return &sport->port_guid_wwn;
2538 			if (strcmp(sport->port_gid, name) == 0)
2539 				return &sport->port_gid_wwn;
2540 		}
2541 	}
2542 
2543 	return NULL;
2544 }
2545 
2546 static struct se_wwn *srpt_lookup_wwn(const char *name)
2547 {
2548 	struct se_wwn *wwn;
2549 
2550 	spin_lock(&srpt_dev_lock);
2551 	wwn = __srpt_lookup_wwn(name);
2552 	spin_unlock(&srpt_dev_lock);
2553 
2554 	return wwn;
2555 }
2556 
2557 static void srpt_free_srq(struct srpt_device *sdev)
2558 {
2559 	if (!sdev->srq)
2560 		return;
2561 
2562 	ib_destroy_srq(sdev->srq);
2563 	srpt_free_ioctx_ring((struct srpt_ioctx **)sdev->ioctx_ring, sdev,
2564 			     sdev->srq_size, srp_max_req_size, DMA_FROM_DEVICE);
2565 	sdev->srq = NULL;
2566 }
2567 
2568 static int srpt_alloc_srq(struct srpt_device *sdev)
2569 {
2570 	struct ib_srq_init_attr srq_attr = {
2571 		.event_handler = srpt_srq_event,
2572 		.srq_context = (void *)sdev,
2573 		.attr.max_wr = sdev->srq_size,
2574 		.attr.max_sge = 1,
2575 		.srq_type = IB_SRQT_BASIC,
2576 	};
2577 	struct ib_device *device = sdev->device;
2578 	struct ib_srq *srq;
2579 	int i;
2580 
2581 	WARN_ON_ONCE(sdev->srq);
2582 	srq = ib_create_srq(sdev->pd, &srq_attr);
2583 	if (IS_ERR(srq)) {
2584 		pr_debug("ib_create_srq() failed: %ld\n", PTR_ERR(srq));
2585 		return PTR_ERR(srq);
2586 	}
2587 
2588 	pr_debug("create SRQ #wr= %d max_allow=%d dev= %s\n", sdev->srq_size,
2589 		 sdev->device->attrs.max_srq_wr, device->name);
2590 
2591 	sdev->ioctx_ring = (struct srpt_recv_ioctx **)
2592 		srpt_alloc_ioctx_ring(sdev, sdev->srq_size,
2593 				      sizeof(*sdev->ioctx_ring[0]),
2594 				      srp_max_req_size, DMA_FROM_DEVICE);
2595 	if (!sdev->ioctx_ring) {
2596 		ib_destroy_srq(srq);
2597 		return -ENOMEM;
2598 	}
2599 
2600 	sdev->use_srq = true;
2601 	sdev->srq = srq;
2602 
2603 	for (i = 0; i < sdev->srq_size; ++i)
2604 		srpt_post_recv(sdev, NULL, sdev->ioctx_ring[i]);
2605 
2606 	return 0;
2607 }
2608 
2609 static int srpt_use_srq(struct srpt_device *sdev, bool use_srq)
2610 {
2611 	struct ib_device *device = sdev->device;
2612 	int ret = 0;
2613 
2614 	if (!use_srq) {
2615 		srpt_free_srq(sdev);
2616 		sdev->use_srq = false;
2617 	} else if (use_srq && !sdev->srq) {
2618 		ret = srpt_alloc_srq(sdev);
2619 	}
2620 	pr_debug("%s(%s): use_srq = %d; ret = %d\n", __func__, device->name,
2621 		 sdev->use_srq, ret);
2622 	return ret;
2623 }
2624 
2625 /**
2626  * srpt_add_one() - Infiniband device addition callback function.
2627  */
2628 static void srpt_add_one(struct ib_device *device)
2629 {
2630 	struct srpt_device *sdev;
2631 	struct srpt_port *sport;
2632 	int i;
2633 
2634 	pr_debug("device = %p\n", device);
2635 
2636 	sdev = kzalloc(sizeof(*sdev), GFP_KERNEL);
2637 	if (!sdev)
2638 		goto err;
2639 
2640 	sdev->device = device;
2641 	INIT_LIST_HEAD(&sdev->rch_list);
2642 	init_waitqueue_head(&sdev->ch_releaseQ);
2643 	mutex_init(&sdev->mutex);
2644 
2645 	sdev->pd = ib_alloc_pd(device, 0);
2646 	if (IS_ERR(sdev->pd))
2647 		goto free_dev;
2648 
2649 	sdev->lkey = sdev->pd->local_dma_lkey;
2650 
2651 	sdev->srq_size = min(srpt_srq_size, sdev->device->attrs.max_srq_wr);
2652 
2653 	srpt_use_srq(sdev, sdev->port[0].port_attrib.use_srq);
2654 
2655 	if (!srpt_service_guid)
2656 		srpt_service_guid = be64_to_cpu(device->node_guid);
2657 
2658 	sdev->cm_id = ib_create_cm_id(device, srpt_cm_handler, sdev);
2659 	if (IS_ERR(sdev->cm_id))
2660 		goto err_ring;
2661 
2662 	/* print out target login information */
2663 	pr_debug("Target login info: id_ext=%016llx,ioc_guid=%016llx,"
2664 		 "pkey=ffff,service_id=%016llx\n", srpt_service_guid,
2665 		 srpt_service_guid, srpt_service_guid);
2666 
2667 	/*
2668 	 * We do not have a consistent service_id (ie. also id_ext of target_id)
2669 	 * to identify this target. We currently use the guid of the first HCA
2670 	 * in the system as service_id; therefore, the target_id will change
2671 	 * if this HCA is gone bad and replaced by different HCA
2672 	 */
2673 	if (ib_cm_listen(sdev->cm_id, cpu_to_be64(srpt_service_guid), 0))
2674 		goto err_cm;
2675 
2676 	INIT_IB_EVENT_HANDLER(&sdev->event_handler, sdev->device,
2677 			      srpt_event_handler);
2678 	ib_register_event_handler(&sdev->event_handler);
2679 
2680 	WARN_ON(sdev->device->phys_port_cnt > ARRAY_SIZE(sdev->port));
2681 
2682 	for (i = 1; i <= sdev->device->phys_port_cnt; i++) {
2683 		sport = &sdev->port[i - 1];
2684 		sport->sdev = sdev;
2685 		sport->port = i;
2686 		sport->port_attrib.srp_max_rdma_size = DEFAULT_MAX_RDMA_SIZE;
2687 		sport->port_attrib.srp_max_rsp_size = DEFAULT_MAX_RSP_SIZE;
2688 		sport->port_attrib.srp_sq_size = DEF_SRPT_SQ_SIZE;
2689 		sport->port_attrib.use_srq = false;
2690 		INIT_WORK(&sport->work, srpt_refresh_port_work);
2691 
2692 		if (srpt_refresh_port(sport)) {
2693 			pr_err("MAD registration failed for %s-%d.\n",
2694 			       sdev->device->name, i);
2695 			goto err_event;
2696 		}
2697 	}
2698 
2699 	spin_lock(&srpt_dev_lock);
2700 	list_add_tail(&sdev->list, &srpt_dev_list);
2701 	spin_unlock(&srpt_dev_lock);
2702 
2703 out:
2704 	ib_set_client_data(device, &srpt_client, sdev);
2705 	pr_debug("added %s.\n", device->name);
2706 	return;
2707 
2708 err_event:
2709 	ib_unregister_event_handler(&sdev->event_handler);
2710 err_cm:
2711 	ib_destroy_cm_id(sdev->cm_id);
2712 err_ring:
2713 	srpt_free_srq(sdev);
2714 	ib_dealloc_pd(sdev->pd);
2715 free_dev:
2716 	kfree(sdev);
2717 err:
2718 	sdev = NULL;
2719 	pr_info("%s(%s) failed.\n", __func__, device->name);
2720 	goto out;
2721 }
2722 
2723 /**
2724  * srpt_remove_one() - InfiniBand device removal callback function.
2725  */
2726 static void srpt_remove_one(struct ib_device *device, void *client_data)
2727 {
2728 	struct srpt_device *sdev = client_data;
2729 	int i;
2730 
2731 	if (!sdev) {
2732 		pr_info("%s(%s): nothing to do.\n", __func__, device->name);
2733 		return;
2734 	}
2735 
2736 	srpt_unregister_mad_agent(sdev);
2737 
2738 	ib_unregister_event_handler(&sdev->event_handler);
2739 
2740 	/* Cancel any work queued by the just unregistered IB event handler. */
2741 	for (i = 0; i < sdev->device->phys_port_cnt; i++)
2742 		cancel_work_sync(&sdev->port[i].work);
2743 
2744 	ib_destroy_cm_id(sdev->cm_id);
2745 
2746 	/*
2747 	 * Unregistering a target must happen after destroying sdev->cm_id
2748 	 * such that no new SRP_LOGIN_REQ information units can arrive while
2749 	 * destroying the target.
2750 	 */
2751 	spin_lock(&srpt_dev_lock);
2752 	list_del(&sdev->list);
2753 	spin_unlock(&srpt_dev_lock);
2754 	srpt_release_sdev(sdev);
2755 
2756 	srpt_free_srq(sdev);
2757 
2758 	ib_dealloc_pd(sdev->pd);
2759 
2760 	kfree(sdev);
2761 }
2762 
2763 static struct ib_client srpt_client = {
2764 	.name = DRV_NAME,
2765 	.add = srpt_add_one,
2766 	.remove = srpt_remove_one
2767 };
2768 
2769 static int srpt_check_true(struct se_portal_group *se_tpg)
2770 {
2771 	return 1;
2772 }
2773 
2774 static int srpt_check_false(struct se_portal_group *se_tpg)
2775 {
2776 	return 0;
2777 }
2778 
2779 static char *srpt_get_fabric_name(void)
2780 {
2781 	return "srpt";
2782 }
2783 
2784 static struct srpt_port *srpt_tpg_to_sport(struct se_portal_group *tpg)
2785 {
2786 	return tpg->se_tpg_wwn->priv;
2787 }
2788 
2789 static char *srpt_get_fabric_wwn(struct se_portal_group *tpg)
2790 {
2791 	struct srpt_port *sport = srpt_tpg_to_sport(tpg);
2792 
2793 	WARN_ON_ONCE(tpg != &sport->port_guid_tpg &&
2794 		     tpg != &sport->port_gid_tpg);
2795 	return tpg == &sport->port_guid_tpg ? sport->port_guid :
2796 		sport->port_gid;
2797 }
2798 
2799 static u16 srpt_get_tag(struct se_portal_group *tpg)
2800 {
2801 	return 1;
2802 }
2803 
2804 static u32 srpt_tpg_get_inst_index(struct se_portal_group *se_tpg)
2805 {
2806 	return 1;
2807 }
2808 
2809 static void srpt_release_cmd(struct se_cmd *se_cmd)
2810 {
2811 	struct srpt_send_ioctx *ioctx = container_of(se_cmd,
2812 				struct srpt_send_ioctx, cmd);
2813 	struct srpt_rdma_ch *ch = ioctx->ch;
2814 	unsigned long flags;
2815 
2816 	WARN_ON_ONCE(ioctx->state != SRPT_STATE_DONE &&
2817 		     !(ioctx->cmd.transport_state & CMD_T_ABORTED));
2818 
2819 	if (ioctx->n_rw_ctx) {
2820 		srpt_free_rw_ctxs(ch, ioctx);
2821 		ioctx->n_rw_ctx = 0;
2822 	}
2823 
2824 	spin_lock_irqsave(&ch->spinlock, flags);
2825 	list_add(&ioctx->free_list, &ch->free_list);
2826 	spin_unlock_irqrestore(&ch->spinlock, flags);
2827 }
2828 
2829 /**
2830  * srpt_close_session() - Forcibly close a session.
2831  *
2832  * Callback function invoked by the TCM core to clean up sessions associated
2833  * with a node ACL when the user invokes
2834  * rmdir /sys/kernel/config/target/$driver/$port/$tpg/acls/$i_port_id
2835  */
2836 static void srpt_close_session(struct se_session *se_sess)
2837 {
2838 	struct srpt_rdma_ch *ch = se_sess->fabric_sess_ptr;
2839 	struct srpt_device *sdev = ch->sport->sdev;
2840 
2841 	mutex_lock(&sdev->mutex);
2842 	srpt_disconnect_ch_sync(ch);
2843 	mutex_unlock(&sdev->mutex);
2844 }
2845 
2846 /**
2847  * srpt_sess_get_index() - Return the value of scsiAttIntrPortIndex (SCSI-MIB).
2848  *
2849  * A quote from RFC 4455 (SCSI-MIB) about this MIB object:
2850  * This object represents an arbitrary integer used to uniquely identify a
2851  * particular attached remote initiator port to a particular SCSI target port
2852  * within a particular SCSI target device within a particular SCSI instance.
2853  */
2854 static u32 srpt_sess_get_index(struct se_session *se_sess)
2855 {
2856 	return 0;
2857 }
2858 
2859 static void srpt_set_default_node_attrs(struct se_node_acl *nacl)
2860 {
2861 }
2862 
2863 /* Note: only used from inside debug printk's by the TCM core. */
2864 static int srpt_get_tcm_cmd_state(struct se_cmd *se_cmd)
2865 {
2866 	struct srpt_send_ioctx *ioctx;
2867 
2868 	ioctx = container_of(se_cmd, struct srpt_send_ioctx, cmd);
2869 	return srpt_get_cmd_state(ioctx);
2870 }
2871 
2872 static int srpt_parse_guid(u64 *guid, const char *name)
2873 {
2874 	u16 w[4];
2875 	int ret = -EINVAL;
2876 
2877 	if (sscanf(name, "%hx:%hx:%hx:%hx", &w[0], &w[1], &w[2], &w[3]) != 4)
2878 		goto out;
2879 	*guid = get_unaligned_be64(w);
2880 	ret = 0;
2881 out:
2882 	return ret;
2883 }
2884 
2885 /**
2886  * srpt_parse_i_port_id() - Parse an initiator port ID.
2887  * @name: ASCII representation of a 128-bit initiator port ID.
2888  * @i_port_id: Binary 128-bit port ID.
2889  */
2890 static int srpt_parse_i_port_id(u8 i_port_id[16], const char *name)
2891 {
2892 	const char *p;
2893 	unsigned len, count, leading_zero_bytes;
2894 	int ret;
2895 
2896 	p = name;
2897 	if (strncasecmp(p, "0x", 2) == 0)
2898 		p += 2;
2899 	ret = -EINVAL;
2900 	len = strlen(p);
2901 	if (len % 2)
2902 		goto out;
2903 	count = min(len / 2, 16U);
2904 	leading_zero_bytes = 16 - count;
2905 	memset(i_port_id, 0, leading_zero_bytes);
2906 	ret = hex2bin(i_port_id + leading_zero_bytes, p, count);
2907 	if (ret < 0)
2908 		pr_debug("hex2bin failed for srpt_parse_i_port_id: %d\n", ret);
2909 out:
2910 	return ret;
2911 }
2912 
2913 /*
2914  * configfs callback function invoked for
2915  * mkdir /sys/kernel/config/target/$driver/$port/$tpg/acls/$i_port_id
2916  */
2917 static int srpt_init_nodeacl(struct se_node_acl *se_nacl, const char *name)
2918 {
2919 	u64 guid;
2920 	u8 i_port_id[16];
2921 	int ret;
2922 
2923 	ret = srpt_parse_guid(&guid, name);
2924 	if (ret < 0)
2925 		ret = srpt_parse_i_port_id(i_port_id, name);
2926 	if (ret < 0)
2927 		pr_err("invalid initiator port ID %s\n", name);
2928 	return ret;
2929 }
2930 
2931 static ssize_t srpt_tpg_attrib_srp_max_rdma_size_show(struct config_item *item,
2932 		char *page)
2933 {
2934 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
2935 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
2936 
2937 	return sprintf(page, "%u\n", sport->port_attrib.srp_max_rdma_size);
2938 }
2939 
2940 static ssize_t srpt_tpg_attrib_srp_max_rdma_size_store(struct config_item *item,
2941 		const char *page, size_t count)
2942 {
2943 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
2944 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
2945 	unsigned long val;
2946 	int ret;
2947 
2948 	ret = kstrtoul(page, 0, &val);
2949 	if (ret < 0) {
2950 		pr_err("kstrtoul() failed with ret: %d\n", ret);
2951 		return -EINVAL;
2952 	}
2953 	if (val > MAX_SRPT_RDMA_SIZE) {
2954 		pr_err("val: %lu exceeds MAX_SRPT_RDMA_SIZE: %d\n", val,
2955 			MAX_SRPT_RDMA_SIZE);
2956 		return -EINVAL;
2957 	}
2958 	if (val < DEFAULT_MAX_RDMA_SIZE) {
2959 		pr_err("val: %lu smaller than DEFAULT_MAX_RDMA_SIZE: %d\n",
2960 			val, DEFAULT_MAX_RDMA_SIZE);
2961 		return -EINVAL;
2962 	}
2963 	sport->port_attrib.srp_max_rdma_size = val;
2964 
2965 	return count;
2966 }
2967 
2968 static ssize_t srpt_tpg_attrib_srp_max_rsp_size_show(struct config_item *item,
2969 		char *page)
2970 {
2971 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
2972 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
2973 
2974 	return sprintf(page, "%u\n", sport->port_attrib.srp_max_rsp_size);
2975 }
2976 
2977 static ssize_t srpt_tpg_attrib_srp_max_rsp_size_store(struct config_item *item,
2978 		const char *page, size_t count)
2979 {
2980 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
2981 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
2982 	unsigned long val;
2983 	int ret;
2984 
2985 	ret = kstrtoul(page, 0, &val);
2986 	if (ret < 0) {
2987 		pr_err("kstrtoul() failed with ret: %d\n", ret);
2988 		return -EINVAL;
2989 	}
2990 	if (val > MAX_SRPT_RSP_SIZE) {
2991 		pr_err("val: %lu exceeds MAX_SRPT_RSP_SIZE: %d\n", val,
2992 			MAX_SRPT_RSP_SIZE);
2993 		return -EINVAL;
2994 	}
2995 	if (val < MIN_MAX_RSP_SIZE) {
2996 		pr_err("val: %lu smaller than MIN_MAX_RSP_SIZE: %d\n", val,
2997 			MIN_MAX_RSP_SIZE);
2998 		return -EINVAL;
2999 	}
3000 	sport->port_attrib.srp_max_rsp_size = val;
3001 
3002 	return count;
3003 }
3004 
3005 static ssize_t srpt_tpg_attrib_srp_sq_size_show(struct config_item *item,
3006 		char *page)
3007 {
3008 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
3009 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
3010 
3011 	return sprintf(page, "%u\n", sport->port_attrib.srp_sq_size);
3012 }
3013 
3014 static ssize_t srpt_tpg_attrib_srp_sq_size_store(struct config_item *item,
3015 		const char *page, size_t count)
3016 {
3017 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
3018 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
3019 	unsigned long val;
3020 	int ret;
3021 
3022 	ret = kstrtoul(page, 0, &val);
3023 	if (ret < 0) {
3024 		pr_err("kstrtoul() failed with ret: %d\n", ret);
3025 		return -EINVAL;
3026 	}
3027 	if (val > MAX_SRPT_SRQ_SIZE) {
3028 		pr_err("val: %lu exceeds MAX_SRPT_SRQ_SIZE: %d\n", val,
3029 			MAX_SRPT_SRQ_SIZE);
3030 		return -EINVAL;
3031 	}
3032 	if (val < MIN_SRPT_SRQ_SIZE) {
3033 		pr_err("val: %lu smaller than MIN_SRPT_SRQ_SIZE: %d\n", val,
3034 			MIN_SRPT_SRQ_SIZE);
3035 		return -EINVAL;
3036 	}
3037 	sport->port_attrib.srp_sq_size = val;
3038 
3039 	return count;
3040 }
3041 
3042 static ssize_t srpt_tpg_attrib_use_srq_show(struct config_item *item,
3043 					    char *page)
3044 {
3045 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
3046 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
3047 
3048 	return sprintf(page, "%d\n", sport->port_attrib.use_srq);
3049 }
3050 
3051 static ssize_t srpt_tpg_attrib_use_srq_store(struct config_item *item,
3052 					     const char *page, size_t count)
3053 {
3054 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
3055 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
3056 	struct srpt_device *sdev = sport->sdev;
3057 	unsigned long val;
3058 	bool enabled;
3059 	int ret;
3060 
3061 	ret = kstrtoul(page, 0, &val);
3062 	if (ret < 0)
3063 		return ret;
3064 	if (val != !!val)
3065 		return -EINVAL;
3066 
3067 	ret = mutex_lock_interruptible(&sdev->mutex);
3068 	if (ret < 0)
3069 		return ret;
3070 	enabled = sport->enabled;
3071 	/* Log out all initiator systems before changing 'use_srq'. */
3072 	srpt_set_enabled(sport, false);
3073 	sport->port_attrib.use_srq = val;
3074 	srpt_use_srq(sdev, sport->port_attrib.use_srq);
3075 	srpt_set_enabled(sport, enabled);
3076 	mutex_unlock(&sdev->mutex);
3077 
3078 	return count;
3079 }
3080 
3081 CONFIGFS_ATTR(srpt_tpg_attrib_,  srp_max_rdma_size);
3082 CONFIGFS_ATTR(srpt_tpg_attrib_,  srp_max_rsp_size);
3083 CONFIGFS_ATTR(srpt_tpg_attrib_,  srp_sq_size);
3084 CONFIGFS_ATTR(srpt_tpg_attrib_,  use_srq);
3085 
3086 static struct configfs_attribute *srpt_tpg_attrib_attrs[] = {
3087 	&srpt_tpg_attrib_attr_srp_max_rdma_size,
3088 	&srpt_tpg_attrib_attr_srp_max_rsp_size,
3089 	&srpt_tpg_attrib_attr_srp_sq_size,
3090 	&srpt_tpg_attrib_attr_use_srq,
3091 	NULL,
3092 };
3093 
3094 static ssize_t srpt_tpg_enable_show(struct config_item *item, char *page)
3095 {
3096 	struct se_portal_group *se_tpg = to_tpg(item);
3097 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
3098 
3099 	return snprintf(page, PAGE_SIZE, "%d\n", (sport->enabled) ? 1: 0);
3100 }
3101 
3102 static ssize_t srpt_tpg_enable_store(struct config_item *item,
3103 		const char *page, size_t count)
3104 {
3105 	struct se_portal_group *se_tpg = to_tpg(item);
3106 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
3107 	struct srpt_device *sdev = sport->sdev;
3108 	unsigned long tmp;
3109         int ret;
3110 
3111 	ret = kstrtoul(page, 0, &tmp);
3112 	if (ret < 0) {
3113 		pr_err("Unable to extract srpt_tpg_store_enable\n");
3114 		return -EINVAL;
3115 	}
3116 
3117 	if ((tmp != 0) && (tmp != 1)) {
3118 		pr_err("Illegal value for srpt_tpg_store_enable: %lu\n", tmp);
3119 		return -EINVAL;
3120 	}
3121 
3122 	mutex_lock(&sdev->mutex);
3123 	srpt_set_enabled(sport, tmp);
3124 	mutex_unlock(&sdev->mutex);
3125 
3126 	return count;
3127 }
3128 
3129 CONFIGFS_ATTR(srpt_tpg_, enable);
3130 
3131 static struct configfs_attribute *srpt_tpg_attrs[] = {
3132 	&srpt_tpg_attr_enable,
3133 	NULL,
3134 };
3135 
3136 /**
3137  * configfs callback invoked for
3138  * mkdir /sys/kernel/config/target/$driver/$port/$tpg
3139  */
3140 static struct se_portal_group *srpt_make_tpg(struct se_wwn *wwn,
3141 					     struct config_group *group,
3142 					     const char *name)
3143 {
3144 	struct srpt_port *sport = wwn->priv;
3145 	static struct se_portal_group *tpg;
3146 	int res;
3147 
3148 	WARN_ON_ONCE(wwn != &sport->port_guid_wwn &&
3149 		     wwn != &sport->port_gid_wwn);
3150 	tpg = wwn == &sport->port_guid_wwn ? &sport->port_guid_tpg :
3151 		&sport->port_gid_tpg;
3152 	res = core_tpg_register(wwn, tpg, SCSI_PROTOCOL_SRP);
3153 	if (res)
3154 		return ERR_PTR(res);
3155 
3156 	return tpg;
3157 }
3158 
3159 /**
3160  * configfs callback invoked for
3161  * rmdir /sys/kernel/config/target/$driver/$port/$tpg
3162  */
3163 static void srpt_drop_tpg(struct se_portal_group *tpg)
3164 {
3165 	struct srpt_port *sport = srpt_tpg_to_sport(tpg);
3166 
3167 	sport->enabled = false;
3168 	core_tpg_deregister(tpg);
3169 }
3170 
3171 /**
3172  * configfs callback invoked for
3173  * mkdir /sys/kernel/config/target/$driver/$port
3174  */
3175 static struct se_wwn *srpt_make_tport(struct target_fabric_configfs *tf,
3176 				      struct config_group *group,
3177 				      const char *name)
3178 {
3179 	return srpt_lookup_wwn(name) ? : ERR_PTR(-EINVAL);
3180 }
3181 
3182 /**
3183  * configfs callback invoked for
3184  * rmdir /sys/kernel/config/target/$driver/$port
3185  */
3186 static void srpt_drop_tport(struct se_wwn *wwn)
3187 {
3188 }
3189 
3190 static ssize_t srpt_wwn_version_show(struct config_item *item, char *buf)
3191 {
3192 	return scnprintf(buf, PAGE_SIZE, "%s\n", DRV_VERSION);
3193 }
3194 
3195 CONFIGFS_ATTR_RO(srpt_wwn_, version);
3196 
3197 static struct configfs_attribute *srpt_wwn_attrs[] = {
3198 	&srpt_wwn_attr_version,
3199 	NULL,
3200 };
3201 
3202 static const struct target_core_fabric_ops srpt_template = {
3203 	.module				= THIS_MODULE,
3204 	.name				= "srpt",
3205 	.get_fabric_name		= srpt_get_fabric_name,
3206 	.tpg_get_wwn			= srpt_get_fabric_wwn,
3207 	.tpg_get_tag			= srpt_get_tag,
3208 	.tpg_check_demo_mode		= srpt_check_false,
3209 	.tpg_check_demo_mode_cache	= srpt_check_true,
3210 	.tpg_check_demo_mode_write_protect = srpt_check_true,
3211 	.tpg_check_prod_mode_write_protect = srpt_check_false,
3212 	.tpg_get_inst_index		= srpt_tpg_get_inst_index,
3213 	.release_cmd			= srpt_release_cmd,
3214 	.check_stop_free		= srpt_check_stop_free,
3215 	.close_session			= srpt_close_session,
3216 	.sess_get_index			= srpt_sess_get_index,
3217 	.sess_get_initiator_sid		= NULL,
3218 	.write_pending			= srpt_write_pending,
3219 	.write_pending_status		= srpt_write_pending_status,
3220 	.set_default_node_attributes	= srpt_set_default_node_attrs,
3221 	.get_cmd_state			= srpt_get_tcm_cmd_state,
3222 	.queue_data_in			= srpt_queue_data_in,
3223 	.queue_status			= srpt_queue_status,
3224 	.queue_tm_rsp			= srpt_queue_tm_rsp,
3225 	.aborted_task			= srpt_aborted_task,
3226 	/*
3227 	 * Setup function pointers for generic logic in
3228 	 * target_core_fabric_configfs.c
3229 	 */
3230 	.fabric_make_wwn		= srpt_make_tport,
3231 	.fabric_drop_wwn		= srpt_drop_tport,
3232 	.fabric_make_tpg		= srpt_make_tpg,
3233 	.fabric_drop_tpg		= srpt_drop_tpg,
3234 	.fabric_init_nodeacl		= srpt_init_nodeacl,
3235 
3236 	.tfc_wwn_attrs			= srpt_wwn_attrs,
3237 	.tfc_tpg_base_attrs		= srpt_tpg_attrs,
3238 	.tfc_tpg_attrib_attrs		= srpt_tpg_attrib_attrs,
3239 };
3240 
3241 /**
3242  * srpt_init_module() - Kernel module initialization.
3243  *
3244  * Note: Since ib_register_client() registers callback functions, and since at
3245  * least one of these callback functions (srpt_add_one()) calls target core
3246  * functions, this driver must be registered with the target core before
3247  * ib_register_client() is called.
3248  */
3249 static int __init srpt_init_module(void)
3250 {
3251 	int ret;
3252 
3253 	ret = -EINVAL;
3254 	if (srp_max_req_size < MIN_MAX_REQ_SIZE) {
3255 		pr_err("invalid value %d for kernel module parameter"
3256 		       " srp_max_req_size -- must be at least %d.\n",
3257 		       srp_max_req_size, MIN_MAX_REQ_SIZE);
3258 		goto out;
3259 	}
3260 
3261 	if (srpt_srq_size < MIN_SRPT_SRQ_SIZE
3262 	    || srpt_srq_size > MAX_SRPT_SRQ_SIZE) {
3263 		pr_err("invalid value %d for kernel module parameter"
3264 		       " srpt_srq_size -- must be in the range [%d..%d].\n",
3265 		       srpt_srq_size, MIN_SRPT_SRQ_SIZE, MAX_SRPT_SRQ_SIZE);
3266 		goto out;
3267 	}
3268 
3269 	ret = target_register_template(&srpt_template);
3270 	if (ret)
3271 		goto out;
3272 
3273 	ret = ib_register_client(&srpt_client);
3274 	if (ret) {
3275 		pr_err("couldn't register IB client\n");
3276 		goto out_unregister_target;
3277 	}
3278 
3279 	return 0;
3280 
3281 out_unregister_target:
3282 	target_unregister_template(&srpt_template);
3283 out:
3284 	return ret;
3285 }
3286 
3287 static void __exit srpt_cleanup_module(void)
3288 {
3289 	ib_unregister_client(&srpt_client);
3290 	target_unregister_template(&srpt_template);
3291 }
3292 
3293 module_init(srpt_init_module);
3294 module_exit(srpt_cleanup_module);
3295