xref: /linux/drivers/infiniband/ulp/srpt/ib_srpt.c (revision b2d0f5d5dc53532e6f07bc546a476a55ebdfe0f3)
1 /*
2  * Copyright (c) 2006 - 2009 Mellanox Technology Inc.  All rights reserved.
3  * Copyright (C) 2008 - 2011 Bart Van Assche <bvanassche@acm.org>.
4  *
5  * This software is available to you under a choice of one of two
6  * licenses.  You may choose to be licensed under the terms of the GNU
7  * General Public License (GPL) Version 2, available from the file
8  * COPYING in the main directory of this source tree, or the
9  * OpenIB.org BSD license below:
10  *
11  *     Redistribution and use in source and binary forms, with or
12  *     without modification, are permitted provided that the following
13  *     conditions are met:
14  *
15  *      - Redistributions of source code must retain the above
16  *        copyright notice, this list of conditions and the following
17  *        disclaimer.
18  *
19  *      - Redistributions in binary form must reproduce the above
20  *        copyright notice, this list of conditions and the following
21  *        disclaimer in the documentation and/or other materials
22  *        provided with the distribution.
23  *
24  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
25  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
26  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
27  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
28  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
29  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
30  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
31  * SOFTWARE.
32  *
33  */
34 
35 #include <linux/module.h>
36 #include <linux/init.h>
37 #include <linux/slab.h>
38 #include <linux/err.h>
39 #include <linux/ctype.h>
40 #include <linux/kthread.h>
41 #include <linux/string.h>
42 #include <linux/delay.h>
43 #include <linux/atomic.h>
44 #include <scsi/scsi_proto.h>
45 #include <scsi/scsi_tcq.h>
46 #include <target/target_core_base.h>
47 #include <target/target_core_fabric.h>
48 #include "ib_srpt.h"
49 
50 /* Name of this kernel module. */
51 #define DRV_NAME		"ib_srpt"
52 #define DRV_VERSION		"2.0.0"
53 #define DRV_RELDATE		"2011-02-14"
54 
55 #define SRPT_ID_STRING	"Linux SRP target"
56 
57 #undef pr_fmt
58 #define pr_fmt(fmt) DRV_NAME " " fmt
59 
60 MODULE_AUTHOR("Vu Pham and Bart Van Assche");
61 MODULE_DESCRIPTION("InfiniBand SCSI RDMA Protocol target "
62 		   "v" DRV_VERSION " (" DRV_RELDATE ")");
63 MODULE_LICENSE("Dual BSD/GPL");
64 
65 /*
66  * Global Variables
67  */
68 
69 static u64 srpt_service_guid;
70 static DEFINE_SPINLOCK(srpt_dev_lock);	/* Protects srpt_dev_list. */
71 static LIST_HEAD(srpt_dev_list);	/* List of srpt_device structures. */
72 
73 static unsigned srp_max_req_size = DEFAULT_MAX_REQ_SIZE;
74 module_param(srp_max_req_size, int, 0444);
75 MODULE_PARM_DESC(srp_max_req_size,
76 		 "Maximum size of SRP request messages in bytes.");
77 
78 static int srpt_srq_size = DEFAULT_SRPT_SRQ_SIZE;
79 module_param(srpt_srq_size, int, 0444);
80 MODULE_PARM_DESC(srpt_srq_size,
81 		 "Shared receive queue (SRQ) size.");
82 
83 static int srpt_get_u64_x(char *buffer, struct kernel_param *kp)
84 {
85 	return sprintf(buffer, "0x%016llx", *(u64 *)kp->arg);
86 }
87 module_param_call(srpt_service_guid, NULL, srpt_get_u64_x, &srpt_service_guid,
88 		  0444);
89 MODULE_PARM_DESC(srpt_service_guid,
90 		 "Using this value for ioc_guid, id_ext, and cm_listen_id"
91 		 " instead of using the node_guid of the first HCA.");
92 
93 static struct ib_client srpt_client;
94 static void srpt_release_cmd(struct se_cmd *se_cmd);
95 static void srpt_free_ch(struct kref *kref);
96 static int srpt_queue_status(struct se_cmd *cmd);
97 static void srpt_recv_done(struct ib_cq *cq, struct ib_wc *wc);
98 static void srpt_send_done(struct ib_cq *cq, struct ib_wc *wc);
99 static void srpt_process_wait_list(struct srpt_rdma_ch *ch);
100 
101 /*
102  * The only allowed channel state changes are those that change the channel
103  * state into a state with a higher numerical value. Hence the new > prev test.
104  */
105 static bool srpt_set_ch_state(struct srpt_rdma_ch *ch, enum rdma_ch_state new)
106 {
107 	unsigned long flags;
108 	enum rdma_ch_state prev;
109 	bool changed = false;
110 
111 	spin_lock_irqsave(&ch->spinlock, flags);
112 	prev = ch->state;
113 	if (new > prev) {
114 		ch->state = new;
115 		changed = true;
116 	}
117 	spin_unlock_irqrestore(&ch->spinlock, flags);
118 
119 	return changed;
120 }
121 
122 /**
123  * srpt_event_handler() - Asynchronous IB event callback function.
124  *
125  * Callback function called by the InfiniBand core when an asynchronous IB
126  * event occurs. This callback may occur in interrupt context. See also
127  * section 11.5.2, Set Asynchronous Event Handler in the InfiniBand
128  * Architecture Specification.
129  */
130 static void srpt_event_handler(struct ib_event_handler *handler,
131 			       struct ib_event *event)
132 {
133 	struct srpt_device *sdev;
134 	struct srpt_port *sport;
135 
136 	sdev = ib_get_client_data(event->device, &srpt_client);
137 	if (!sdev || sdev->device != event->device)
138 		return;
139 
140 	pr_debug("ASYNC event= %d on device= %s\n", event->event,
141 		 sdev->device->name);
142 
143 	switch (event->event) {
144 	case IB_EVENT_PORT_ERR:
145 		if (event->element.port_num <= sdev->device->phys_port_cnt) {
146 			sport = &sdev->port[event->element.port_num - 1];
147 			sport->lid = 0;
148 			sport->sm_lid = 0;
149 		}
150 		break;
151 	case IB_EVENT_PORT_ACTIVE:
152 	case IB_EVENT_LID_CHANGE:
153 	case IB_EVENT_PKEY_CHANGE:
154 	case IB_EVENT_SM_CHANGE:
155 	case IB_EVENT_CLIENT_REREGISTER:
156 	case IB_EVENT_GID_CHANGE:
157 		/* Refresh port data asynchronously. */
158 		if (event->element.port_num <= sdev->device->phys_port_cnt) {
159 			sport = &sdev->port[event->element.port_num - 1];
160 			if (!sport->lid && !sport->sm_lid)
161 				schedule_work(&sport->work);
162 		}
163 		break;
164 	default:
165 		pr_err("received unrecognized IB event %d\n",
166 		       event->event);
167 		break;
168 	}
169 }
170 
171 /**
172  * srpt_srq_event() - SRQ event callback function.
173  */
174 static void srpt_srq_event(struct ib_event *event, void *ctx)
175 {
176 	pr_info("SRQ event %d\n", event->event);
177 }
178 
179 static const char *get_ch_state_name(enum rdma_ch_state s)
180 {
181 	switch (s) {
182 	case CH_CONNECTING:
183 		return "connecting";
184 	case CH_LIVE:
185 		return "live";
186 	case CH_DISCONNECTING:
187 		return "disconnecting";
188 	case CH_DRAINING:
189 		return "draining";
190 	case CH_DISCONNECTED:
191 		return "disconnected";
192 	}
193 	return "???";
194 }
195 
196 /**
197  * srpt_qp_event() - QP event callback function.
198  */
199 static void srpt_qp_event(struct ib_event *event, struct srpt_rdma_ch *ch)
200 {
201 	pr_debug("QP event %d on cm_id=%p sess_name=%s state=%d\n",
202 		 event->event, ch->cm_id, ch->sess_name, ch->state);
203 
204 	switch (event->event) {
205 	case IB_EVENT_COMM_EST:
206 		ib_cm_notify(ch->cm_id, event->event);
207 		break;
208 	case IB_EVENT_QP_LAST_WQE_REACHED:
209 		pr_debug("%s-%d, state %s: received Last WQE event.\n",
210 			 ch->sess_name, ch->qp->qp_num,
211 			 get_ch_state_name(ch->state));
212 		break;
213 	default:
214 		pr_err("received unrecognized IB QP event %d\n", event->event);
215 		break;
216 	}
217 }
218 
219 /**
220  * srpt_set_ioc() - Helper function for initializing an IOUnitInfo structure.
221  *
222  * @slot: one-based slot number.
223  * @value: four-bit value.
224  *
225  * Copies the lowest four bits of value in element slot of the array of four
226  * bit elements called c_list (controller list). The index slot is one-based.
227  */
228 static void srpt_set_ioc(u8 *c_list, u32 slot, u8 value)
229 {
230 	u16 id;
231 	u8 tmp;
232 
233 	id = (slot - 1) / 2;
234 	if (slot & 0x1) {
235 		tmp = c_list[id] & 0xf;
236 		c_list[id] = (value << 4) | tmp;
237 	} else {
238 		tmp = c_list[id] & 0xf0;
239 		c_list[id] = (value & 0xf) | tmp;
240 	}
241 }
242 
243 /**
244  * srpt_get_class_port_info() - Copy ClassPortInfo to a management datagram.
245  *
246  * See also section 16.3.3.1 ClassPortInfo in the InfiniBand Architecture
247  * Specification.
248  */
249 static void srpt_get_class_port_info(struct ib_dm_mad *mad)
250 {
251 	struct ib_class_port_info *cif;
252 
253 	cif = (struct ib_class_port_info *)mad->data;
254 	memset(cif, 0, sizeof(*cif));
255 	cif->base_version = 1;
256 	cif->class_version = 1;
257 
258 	ib_set_cpi_resp_time(cif, 20);
259 	mad->mad_hdr.status = 0;
260 }
261 
262 /**
263  * srpt_get_iou() - Write IOUnitInfo to a management datagram.
264  *
265  * See also section 16.3.3.3 IOUnitInfo in the InfiniBand Architecture
266  * Specification. See also section B.7, table B.6 in the SRP r16a document.
267  */
268 static void srpt_get_iou(struct ib_dm_mad *mad)
269 {
270 	struct ib_dm_iou_info *ioui;
271 	u8 slot;
272 	int i;
273 
274 	ioui = (struct ib_dm_iou_info *)mad->data;
275 	ioui->change_id = cpu_to_be16(1);
276 	ioui->max_controllers = 16;
277 
278 	/* set present for slot 1 and empty for the rest */
279 	srpt_set_ioc(ioui->controller_list, 1, 1);
280 	for (i = 1, slot = 2; i < 16; i++, slot++)
281 		srpt_set_ioc(ioui->controller_list, slot, 0);
282 
283 	mad->mad_hdr.status = 0;
284 }
285 
286 /**
287  * srpt_get_ioc() - Write IOControllerprofile to a management datagram.
288  *
289  * See also section 16.3.3.4 IOControllerProfile in the InfiniBand
290  * Architecture Specification. See also section B.7, table B.7 in the SRP
291  * r16a document.
292  */
293 static void srpt_get_ioc(struct srpt_port *sport, u32 slot,
294 			 struct ib_dm_mad *mad)
295 {
296 	struct srpt_device *sdev = sport->sdev;
297 	struct ib_dm_ioc_profile *iocp;
298 
299 	iocp = (struct ib_dm_ioc_profile *)mad->data;
300 
301 	if (!slot || slot > 16) {
302 		mad->mad_hdr.status
303 			= cpu_to_be16(DM_MAD_STATUS_INVALID_FIELD);
304 		return;
305 	}
306 
307 	if (slot > 2) {
308 		mad->mad_hdr.status
309 			= cpu_to_be16(DM_MAD_STATUS_NO_IOC);
310 		return;
311 	}
312 
313 	memset(iocp, 0, sizeof(*iocp));
314 	strcpy(iocp->id_string, SRPT_ID_STRING);
315 	iocp->guid = cpu_to_be64(srpt_service_guid);
316 	iocp->vendor_id = cpu_to_be32(sdev->device->attrs.vendor_id);
317 	iocp->device_id = cpu_to_be32(sdev->device->attrs.vendor_part_id);
318 	iocp->device_version = cpu_to_be16(sdev->device->attrs.hw_ver);
319 	iocp->subsys_vendor_id = cpu_to_be32(sdev->device->attrs.vendor_id);
320 	iocp->subsys_device_id = 0x0;
321 	iocp->io_class = cpu_to_be16(SRP_REV16A_IB_IO_CLASS);
322 	iocp->io_subclass = cpu_to_be16(SRP_IO_SUBCLASS);
323 	iocp->protocol = cpu_to_be16(SRP_PROTOCOL);
324 	iocp->protocol_version = cpu_to_be16(SRP_PROTOCOL_VERSION);
325 	iocp->send_queue_depth = cpu_to_be16(sdev->srq_size);
326 	iocp->rdma_read_depth = 4;
327 	iocp->send_size = cpu_to_be32(srp_max_req_size);
328 	iocp->rdma_size = cpu_to_be32(min(sport->port_attrib.srp_max_rdma_size,
329 					  1U << 24));
330 	iocp->num_svc_entries = 1;
331 	iocp->op_cap_mask = SRP_SEND_TO_IOC | SRP_SEND_FROM_IOC |
332 		SRP_RDMA_READ_FROM_IOC | SRP_RDMA_WRITE_FROM_IOC;
333 
334 	mad->mad_hdr.status = 0;
335 }
336 
337 /**
338  * srpt_get_svc_entries() - Write ServiceEntries to a management datagram.
339  *
340  * See also section 16.3.3.5 ServiceEntries in the InfiniBand Architecture
341  * Specification. See also section B.7, table B.8 in the SRP r16a document.
342  */
343 static void srpt_get_svc_entries(u64 ioc_guid,
344 				 u16 slot, u8 hi, u8 lo, struct ib_dm_mad *mad)
345 {
346 	struct ib_dm_svc_entries *svc_entries;
347 
348 	WARN_ON(!ioc_guid);
349 
350 	if (!slot || slot > 16) {
351 		mad->mad_hdr.status
352 			= cpu_to_be16(DM_MAD_STATUS_INVALID_FIELD);
353 		return;
354 	}
355 
356 	if (slot > 2 || lo > hi || hi > 1) {
357 		mad->mad_hdr.status
358 			= cpu_to_be16(DM_MAD_STATUS_NO_IOC);
359 		return;
360 	}
361 
362 	svc_entries = (struct ib_dm_svc_entries *)mad->data;
363 	memset(svc_entries, 0, sizeof(*svc_entries));
364 	svc_entries->service_entries[0].id = cpu_to_be64(ioc_guid);
365 	snprintf(svc_entries->service_entries[0].name,
366 		 sizeof(svc_entries->service_entries[0].name),
367 		 "%s%016llx",
368 		 SRP_SERVICE_NAME_PREFIX,
369 		 ioc_guid);
370 
371 	mad->mad_hdr.status = 0;
372 }
373 
374 /**
375  * srpt_mgmt_method_get() - Process a received management datagram.
376  * @sp:      source port through which the MAD has been received.
377  * @rq_mad:  received MAD.
378  * @rsp_mad: response MAD.
379  */
380 static void srpt_mgmt_method_get(struct srpt_port *sp, struct ib_mad *rq_mad,
381 				 struct ib_dm_mad *rsp_mad)
382 {
383 	u16 attr_id;
384 	u32 slot;
385 	u8 hi, lo;
386 
387 	attr_id = be16_to_cpu(rq_mad->mad_hdr.attr_id);
388 	switch (attr_id) {
389 	case DM_ATTR_CLASS_PORT_INFO:
390 		srpt_get_class_port_info(rsp_mad);
391 		break;
392 	case DM_ATTR_IOU_INFO:
393 		srpt_get_iou(rsp_mad);
394 		break;
395 	case DM_ATTR_IOC_PROFILE:
396 		slot = be32_to_cpu(rq_mad->mad_hdr.attr_mod);
397 		srpt_get_ioc(sp, slot, rsp_mad);
398 		break;
399 	case DM_ATTR_SVC_ENTRIES:
400 		slot = be32_to_cpu(rq_mad->mad_hdr.attr_mod);
401 		hi = (u8) ((slot >> 8) & 0xff);
402 		lo = (u8) (slot & 0xff);
403 		slot = (u16) ((slot >> 16) & 0xffff);
404 		srpt_get_svc_entries(srpt_service_guid,
405 				     slot, hi, lo, rsp_mad);
406 		break;
407 	default:
408 		rsp_mad->mad_hdr.status =
409 		    cpu_to_be16(DM_MAD_STATUS_UNSUP_METHOD_ATTR);
410 		break;
411 	}
412 }
413 
414 /**
415  * srpt_mad_send_handler() - Post MAD-send callback function.
416  */
417 static void srpt_mad_send_handler(struct ib_mad_agent *mad_agent,
418 				  struct ib_mad_send_wc *mad_wc)
419 {
420 	rdma_destroy_ah(mad_wc->send_buf->ah);
421 	ib_free_send_mad(mad_wc->send_buf);
422 }
423 
424 /**
425  * srpt_mad_recv_handler() - MAD reception callback function.
426  */
427 static void srpt_mad_recv_handler(struct ib_mad_agent *mad_agent,
428 				  struct ib_mad_send_buf *send_buf,
429 				  struct ib_mad_recv_wc *mad_wc)
430 {
431 	struct srpt_port *sport = (struct srpt_port *)mad_agent->context;
432 	struct ib_ah *ah;
433 	struct ib_mad_send_buf *rsp;
434 	struct ib_dm_mad *dm_mad;
435 
436 	if (!mad_wc || !mad_wc->recv_buf.mad)
437 		return;
438 
439 	ah = ib_create_ah_from_wc(mad_agent->qp->pd, mad_wc->wc,
440 				  mad_wc->recv_buf.grh, mad_agent->port_num);
441 	if (IS_ERR(ah))
442 		goto err;
443 
444 	BUILD_BUG_ON(offsetof(struct ib_dm_mad, data) != IB_MGMT_DEVICE_HDR);
445 
446 	rsp = ib_create_send_mad(mad_agent, mad_wc->wc->src_qp,
447 				 mad_wc->wc->pkey_index, 0,
448 				 IB_MGMT_DEVICE_HDR, IB_MGMT_DEVICE_DATA,
449 				 GFP_KERNEL,
450 				 IB_MGMT_BASE_VERSION);
451 	if (IS_ERR(rsp))
452 		goto err_rsp;
453 
454 	rsp->ah = ah;
455 
456 	dm_mad = rsp->mad;
457 	memcpy(dm_mad, mad_wc->recv_buf.mad, sizeof(*dm_mad));
458 	dm_mad->mad_hdr.method = IB_MGMT_METHOD_GET_RESP;
459 	dm_mad->mad_hdr.status = 0;
460 
461 	switch (mad_wc->recv_buf.mad->mad_hdr.method) {
462 	case IB_MGMT_METHOD_GET:
463 		srpt_mgmt_method_get(sport, mad_wc->recv_buf.mad, dm_mad);
464 		break;
465 	case IB_MGMT_METHOD_SET:
466 		dm_mad->mad_hdr.status =
467 		    cpu_to_be16(DM_MAD_STATUS_UNSUP_METHOD_ATTR);
468 		break;
469 	default:
470 		dm_mad->mad_hdr.status =
471 		    cpu_to_be16(DM_MAD_STATUS_UNSUP_METHOD);
472 		break;
473 	}
474 
475 	if (!ib_post_send_mad(rsp, NULL)) {
476 		ib_free_recv_mad(mad_wc);
477 		/* will destroy_ah & free_send_mad in send completion */
478 		return;
479 	}
480 
481 	ib_free_send_mad(rsp);
482 
483 err_rsp:
484 	rdma_destroy_ah(ah);
485 err:
486 	ib_free_recv_mad(mad_wc);
487 }
488 
489 /**
490  * srpt_refresh_port() - Configure a HCA port.
491  *
492  * Enable InfiniBand management datagram processing, update the cached sm_lid,
493  * lid and gid values, and register a callback function for processing MADs
494  * on the specified port.
495  *
496  * Note: It is safe to call this function more than once for the same port.
497  */
498 static int srpt_refresh_port(struct srpt_port *sport)
499 {
500 	struct ib_mad_reg_req reg_req;
501 	struct ib_port_modify port_modify;
502 	struct ib_port_attr port_attr;
503 	__be16 *guid;
504 	int ret;
505 
506 	memset(&port_modify, 0, sizeof(port_modify));
507 	port_modify.set_port_cap_mask = IB_PORT_DEVICE_MGMT_SUP;
508 	port_modify.clr_port_cap_mask = 0;
509 
510 	ret = ib_modify_port(sport->sdev->device, sport->port, 0, &port_modify);
511 	if (ret)
512 		goto err_mod_port;
513 
514 	ret = ib_query_port(sport->sdev->device, sport->port, &port_attr);
515 	if (ret)
516 		goto err_query_port;
517 
518 	sport->sm_lid = port_attr.sm_lid;
519 	sport->lid = port_attr.lid;
520 
521 	ret = ib_query_gid(sport->sdev->device, sport->port, 0, &sport->gid,
522 			   NULL);
523 	if (ret)
524 		goto err_query_port;
525 
526 	sport->port_guid_wwn.priv = sport;
527 	guid = (__be16 *)&sport->gid.global.interface_id;
528 	snprintf(sport->port_guid, sizeof(sport->port_guid),
529 		 "%04x:%04x:%04x:%04x",
530 		 be16_to_cpu(guid[0]), be16_to_cpu(guid[1]),
531 		 be16_to_cpu(guid[2]), be16_to_cpu(guid[3]));
532 	sport->port_gid_wwn.priv = sport;
533 	snprintf(sport->port_gid, sizeof(sport->port_gid),
534 		 "0x%016llx%016llx",
535 		 be64_to_cpu(sport->gid.global.subnet_prefix),
536 		 be64_to_cpu(sport->gid.global.interface_id));
537 
538 	if (!sport->mad_agent) {
539 		memset(&reg_req, 0, sizeof(reg_req));
540 		reg_req.mgmt_class = IB_MGMT_CLASS_DEVICE_MGMT;
541 		reg_req.mgmt_class_version = IB_MGMT_BASE_VERSION;
542 		set_bit(IB_MGMT_METHOD_GET, reg_req.method_mask);
543 		set_bit(IB_MGMT_METHOD_SET, reg_req.method_mask);
544 
545 		sport->mad_agent = ib_register_mad_agent(sport->sdev->device,
546 							 sport->port,
547 							 IB_QPT_GSI,
548 							 &reg_req, 0,
549 							 srpt_mad_send_handler,
550 							 srpt_mad_recv_handler,
551 							 sport, 0);
552 		if (IS_ERR(sport->mad_agent)) {
553 			ret = PTR_ERR(sport->mad_agent);
554 			sport->mad_agent = NULL;
555 			goto err_query_port;
556 		}
557 	}
558 
559 	return 0;
560 
561 err_query_port:
562 
563 	port_modify.set_port_cap_mask = 0;
564 	port_modify.clr_port_cap_mask = IB_PORT_DEVICE_MGMT_SUP;
565 	ib_modify_port(sport->sdev->device, sport->port, 0, &port_modify);
566 
567 err_mod_port:
568 
569 	return ret;
570 }
571 
572 /**
573  * srpt_unregister_mad_agent() - Unregister MAD callback functions.
574  *
575  * Note: It is safe to call this function more than once for the same device.
576  */
577 static void srpt_unregister_mad_agent(struct srpt_device *sdev)
578 {
579 	struct ib_port_modify port_modify = {
580 		.clr_port_cap_mask = IB_PORT_DEVICE_MGMT_SUP,
581 	};
582 	struct srpt_port *sport;
583 	int i;
584 
585 	for (i = 1; i <= sdev->device->phys_port_cnt; i++) {
586 		sport = &sdev->port[i - 1];
587 		WARN_ON(sport->port != i);
588 		if (ib_modify_port(sdev->device, i, 0, &port_modify) < 0)
589 			pr_err("disabling MAD processing failed.\n");
590 		if (sport->mad_agent) {
591 			ib_unregister_mad_agent(sport->mad_agent);
592 			sport->mad_agent = NULL;
593 		}
594 	}
595 }
596 
597 /**
598  * srpt_alloc_ioctx() - Allocate an SRPT I/O context structure.
599  */
600 static struct srpt_ioctx *srpt_alloc_ioctx(struct srpt_device *sdev,
601 					   int ioctx_size, int dma_size,
602 					   enum dma_data_direction dir)
603 {
604 	struct srpt_ioctx *ioctx;
605 
606 	ioctx = kmalloc(ioctx_size, GFP_KERNEL);
607 	if (!ioctx)
608 		goto err;
609 
610 	ioctx->buf = kmalloc(dma_size, GFP_KERNEL);
611 	if (!ioctx->buf)
612 		goto err_free_ioctx;
613 
614 	ioctx->dma = ib_dma_map_single(sdev->device, ioctx->buf, dma_size, dir);
615 	if (ib_dma_mapping_error(sdev->device, ioctx->dma))
616 		goto err_free_buf;
617 
618 	return ioctx;
619 
620 err_free_buf:
621 	kfree(ioctx->buf);
622 err_free_ioctx:
623 	kfree(ioctx);
624 err:
625 	return NULL;
626 }
627 
628 /**
629  * srpt_free_ioctx() - Free an SRPT I/O context structure.
630  */
631 static void srpt_free_ioctx(struct srpt_device *sdev, struct srpt_ioctx *ioctx,
632 			    int dma_size, enum dma_data_direction dir)
633 {
634 	if (!ioctx)
635 		return;
636 
637 	ib_dma_unmap_single(sdev->device, ioctx->dma, dma_size, dir);
638 	kfree(ioctx->buf);
639 	kfree(ioctx);
640 }
641 
642 /**
643  * srpt_alloc_ioctx_ring() - Allocate a ring of SRPT I/O context structures.
644  * @sdev:       Device to allocate the I/O context ring for.
645  * @ring_size:  Number of elements in the I/O context ring.
646  * @ioctx_size: I/O context size.
647  * @dma_size:   DMA buffer size.
648  * @dir:        DMA data direction.
649  */
650 static struct srpt_ioctx **srpt_alloc_ioctx_ring(struct srpt_device *sdev,
651 				int ring_size, int ioctx_size,
652 				int dma_size, enum dma_data_direction dir)
653 {
654 	struct srpt_ioctx **ring;
655 	int i;
656 
657 	WARN_ON(ioctx_size != sizeof(struct srpt_recv_ioctx)
658 		&& ioctx_size != sizeof(struct srpt_send_ioctx));
659 
660 	ring = kmalloc(ring_size * sizeof(ring[0]), GFP_KERNEL);
661 	if (!ring)
662 		goto out;
663 	for (i = 0; i < ring_size; ++i) {
664 		ring[i] = srpt_alloc_ioctx(sdev, ioctx_size, dma_size, dir);
665 		if (!ring[i])
666 			goto err;
667 		ring[i]->index = i;
668 	}
669 	goto out;
670 
671 err:
672 	while (--i >= 0)
673 		srpt_free_ioctx(sdev, ring[i], dma_size, dir);
674 	kfree(ring);
675 	ring = NULL;
676 out:
677 	return ring;
678 }
679 
680 /**
681  * srpt_free_ioctx_ring() - Free the ring of SRPT I/O context structures.
682  */
683 static void srpt_free_ioctx_ring(struct srpt_ioctx **ioctx_ring,
684 				 struct srpt_device *sdev, int ring_size,
685 				 int dma_size, enum dma_data_direction dir)
686 {
687 	int i;
688 
689 	for (i = 0; i < ring_size; ++i)
690 		srpt_free_ioctx(sdev, ioctx_ring[i], dma_size, dir);
691 	kfree(ioctx_ring);
692 }
693 
694 /**
695  * srpt_get_cmd_state() - Get the state of a SCSI command.
696  */
697 static enum srpt_command_state srpt_get_cmd_state(struct srpt_send_ioctx *ioctx)
698 {
699 	enum srpt_command_state state;
700 	unsigned long flags;
701 
702 	BUG_ON(!ioctx);
703 
704 	spin_lock_irqsave(&ioctx->spinlock, flags);
705 	state = ioctx->state;
706 	spin_unlock_irqrestore(&ioctx->spinlock, flags);
707 	return state;
708 }
709 
710 /**
711  * srpt_set_cmd_state() - Set the state of a SCSI command.
712  *
713  * Does not modify the state of aborted commands. Returns the previous command
714  * state.
715  */
716 static enum srpt_command_state srpt_set_cmd_state(struct srpt_send_ioctx *ioctx,
717 						  enum srpt_command_state new)
718 {
719 	enum srpt_command_state previous;
720 	unsigned long flags;
721 
722 	BUG_ON(!ioctx);
723 
724 	spin_lock_irqsave(&ioctx->spinlock, flags);
725 	previous = ioctx->state;
726 	if (previous != SRPT_STATE_DONE)
727 		ioctx->state = new;
728 	spin_unlock_irqrestore(&ioctx->spinlock, flags);
729 
730 	return previous;
731 }
732 
733 /**
734  * srpt_test_and_set_cmd_state() - Test and set the state of a command.
735  *
736  * Returns true if and only if the previous command state was equal to 'old'.
737  */
738 static bool srpt_test_and_set_cmd_state(struct srpt_send_ioctx *ioctx,
739 					enum srpt_command_state old,
740 					enum srpt_command_state new)
741 {
742 	enum srpt_command_state previous;
743 	unsigned long flags;
744 
745 	WARN_ON(!ioctx);
746 	WARN_ON(old == SRPT_STATE_DONE);
747 	WARN_ON(new == SRPT_STATE_NEW);
748 
749 	spin_lock_irqsave(&ioctx->spinlock, flags);
750 	previous = ioctx->state;
751 	if (previous == old)
752 		ioctx->state = new;
753 	spin_unlock_irqrestore(&ioctx->spinlock, flags);
754 	return previous == old;
755 }
756 
757 /**
758  * srpt_post_recv() - Post an IB receive request.
759  */
760 static int srpt_post_recv(struct srpt_device *sdev,
761 			  struct srpt_recv_ioctx *ioctx)
762 {
763 	struct ib_sge list;
764 	struct ib_recv_wr wr, *bad_wr;
765 
766 	BUG_ON(!sdev);
767 	list.addr = ioctx->ioctx.dma;
768 	list.length = srp_max_req_size;
769 	list.lkey = sdev->pd->local_dma_lkey;
770 
771 	ioctx->ioctx.cqe.done = srpt_recv_done;
772 	wr.wr_cqe = &ioctx->ioctx.cqe;
773 	wr.next = NULL;
774 	wr.sg_list = &list;
775 	wr.num_sge = 1;
776 
777 	return ib_post_srq_recv(sdev->srq, &wr, &bad_wr);
778 }
779 
780 /**
781  * srpt_zerolength_write() - Perform a zero-length RDMA write.
782  *
783  * A quote from the InfiniBand specification: C9-88: For an HCA responder
784  * using Reliable Connection service, for each zero-length RDMA READ or WRITE
785  * request, the R_Key shall not be validated, even if the request includes
786  * Immediate data.
787  */
788 static int srpt_zerolength_write(struct srpt_rdma_ch *ch)
789 {
790 	struct ib_send_wr wr, *bad_wr;
791 
792 	memset(&wr, 0, sizeof(wr));
793 	wr.opcode = IB_WR_RDMA_WRITE;
794 	wr.wr_cqe = &ch->zw_cqe;
795 	wr.send_flags = IB_SEND_SIGNALED;
796 	return ib_post_send(ch->qp, &wr, &bad_wr);
797 }
798 
799 static void srpt_zerolength_write_done(struct ib_cq *cq, struct ib_wc *wc)
800 {
801 	struct srpt_rdma_ch *ch = cq->cq_context;
802 
803 	if (wc->status == IB_WC_SUCCESS) {
804 		srpt_process_wait_list(ch);
805 	} else {
806 		if (srpt_set_ch_state(ch, CH_DISCONNECTED))
807 			schedule_work(&ch->release_work);
808 		else
809 			WARN_ONCE(1, "%s-%d\n", ch->sess_name, ch->qp->qp_num);
810 	}
811 }
812 
813 static int srpt_alloc_rw_ctxs(struct srpt_send_ioctx *ioctx,
814 		struct srp_direct_buf *db, int nbufs, struct scatterlist **sg,
815 		unsigned *sg_cnt)
816 {
817 	enum dma_data_direction dir = target_reverse_dma_direction(&ioctx->cmd);
818 	struct srpt_rdma_ch *ch = ioctx->ch;
819 	struct scatterlist *prev = NULL;
820 	unsigned prev_nents;
821 	int ret, i;
822 
823 	if (nbufs == 1) {
824 		ioctx->rw_ctxs = &ioctx->s_rw_ctx;
825 	} else {
826 		ioctx->rw_ctxs = kmalloc_array(nbufs, sizeof(*ioctx->rw_ctxs),
827 			GFP_KERNEL);
828 		if (!ioctx->rw_ctxs)
829 			return -ENOMEM;
830 	}
831 
832 	for (i = ioctx->n_rw_ctx; i < nbufs; i++, db++) {
833 		struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
834 		u64 remote_addr = be64_to_cpu(db->va);
835 		u32 size = be32_to_cpu(db->len);
836 		u32 rkey = be32_to_cpu(db->key);
837 
838 		ret = target_alloc_sgl(&ctx->sg, &ctx->nents, size, false,
839 				i < nbufs - 1);
840 		if (ret)
841 			goto unwind;
842 
843 		ret = rdma_rw_ctx_init(&ctx->rw, ch->qp, ch->sport->port,
844 				ctx->sg, ctx->nents, 0, remote_addr, rkey, dir);
845 		if (ret < 0) {
846 			target_free_sgl(ctx->sg, ctx->nents);
847 			goto unwind;
848 		}
849 
850 		ioctx->n_rdma += ret;
851 		ioctx->n_rw_ctx++;
852 
853 		if (prev) {
854 			sg_unmark_end(&prev[prev_nents - 1]);
855 			sg_chain(prev, prev_nents + 1, ctx->sg);
856 		} else {
857 			*sg = ctx->sg;
858 		}
859 
860 		prev = ctx->sg;
861 		prev_nents = ctx->nents;
862 
863 		*sg_cnt += ctx->nents;
864 	}
865 
866 	return 0;
867 
868 unwind:
869 	while (--i >= 0) {
870 		struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
871 
872 		rdma_rw_ctx_destroy(&ctx->rw, ch->qp, ch->sport->port,
873 				ctx->sg, ctx->nents, dir);
874 		target_free_sgl(ctx->sg, ctx->nents);
875 	}
876 	if (ioctx->rw_ctxs != &ioctx->s_rw_ctx)
877 		kfree(ioctx->rw_ctxs);
878 	return ret;
879 }
880 
881 static void srpt_free_rw_ctxs(struct srpt_rdma_ch *ch,
882 				    struct srpt_send_ioctx *ioctx)
883 {
884 	enum dma_data_direction dir = target_reverse_dma_direction(&ioctx->cmd);
885 	int i;
886 
887 	for (i = 0; i < ioctx->n_rw_ctx; i++) {
888 		struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
889 
890 		rdma_rw_ctx_destroy(&ctx->rw, ch->qp, ch->sport->port,
891 				ctx->sg, ctx->nents, dir);
892 		target_free_sgl(ctx->sg, ctx->nents);
893 	}
894 
895 	if (ioctx->rw_ctxs != &ioctx->s_rw_ctx)
896 		kfree(ioctx->rw_ctxs);
897 }
898 
899 static inline void *srpt_get_desc_buf(struct srp_cmd *srp_cmd)
900 {
901 	/*
902 	 * The pointer computations below will only be compiled correctly
903 	 * if srp_cmd::add_data is declared as s8*, u8*, s8[] or u8[], so check
904 	 * whether srp_cmd::add_data has been declared as a byte pointer.
905 	 */
906 	BUILD_BUG_ON(!__same_type(srp_cmd->add_data[0], (s8)0) &&
907 		     !__same_type(srp_cmd->add_data[0], (u8)0));
908 
909 	/*
910 	 * According to the SRP spec, the lower two bits of the 'ADDITIONAL
911 	 * CDB LENGTH' field are reserved and the size in bytes of this field
912 	 * is four times the value specified in bits 3..7. Hence the "& ~3".
913 	 */
914 	return srp_cmd->add_data + (srp_cmd->add_cdb_len & ~3);
915 }
916 
917 /**
918  * srpt_get_desc_tbl() - Parse the data descriptors of an SRP_CMD request.
919  * @ioctx: Pointer to the I/O context associated with the request.
920  * @srp_cmd: Pointer to the SRP_CMD request data.
921  * @dir: Pointer to the variable to which the transfer direction will be
922  *   written.
923  * @data_len: Pointer to the variable to which the total data length of all
924  *   descriptors in the SRP_CMD request will be written.
925  *
926  * This function initializes ioctx->nrbuf and ioctx->r_bufs.
927  *
928  * Returns -EINVAL when the SRP_CMD request contains inconsistent descriptors;
929  * -ENOMEM when memory allocation fails and zero upon success.
930  */
931 static int srpt_get_desc_tbl(struct srpt_send_ioctx *ioctx,
932 		struct srp_cmd *srp_cmd, enum dma_data_direction *dir,
933 		struct scatterlist **sg, unsigned *sg_cnt, u64 *data_len)
934 {
935 	BUG_ON(!dir);
936 	BUG_ON(!data_len);
937 
938 	/*
939 	 * The lower four bits of the buffer format field contain the DATA-IN
940 	 * buffer descriptor format, and the highest four bits contain the
941 	 * DATA-OUT buffer descriptor format.
942 	 */
943 	if (srp_cmd->buf_fmt & 0xf)
944 		/* DATA-IN: transfer data from target to initiator (read). */
945 		*dir = DMA_FROM_DEVICE;
946 	else if (srp_cmd->buf_fmt >> 4)
947 		/* DATA-OUT: transfer data from initiator to target (write). */
948 		*dir = DMA_TO_DEVICE;
949 	else
950 		*dir = DMA_NONE;
951 
952 	/* initialize data_direction early as srpt_alloc_rw_ctxs needs it */
953 	ioctx->cmd.data_direction = *dir;
954 
955 	if (((srp_cmd->buf_fmt & 0xf) == SRP_DATA_DESC_DIRECT) ||
956 	    ((srp_cmd->buf_fmt >> 4) == SRP_DATA_DESC_DIRECT)) {
957 	    	struct srp_direct_buf *db = srpt_get_desc_buf(srp_cmd);
958 
959 		*data_len = be32_to_cpu(db->len);
960 		return srpt_alloc_rw_ctxs(ioctx, db, 1, sg, sg_cnt);
961 	} else if (((srp_cmd->buf_fmt & 0xf) == SRP_DATA_DESC_INDIRECT) ||
962 		   ((srp_cmd->buf_fmt >> 4) == SRP_DATA_DESC_INDIRECT)) {
963 		struct srp_indirect_buf *idb = srpt_get_desc_buf(srp_cmd);
964 		int nbufs = be32_to_cpu(idb->table_desc.len) /
965 				sizeof(struct srp_direct_buf);
966 
967 		if (nbufs >
968 		    (srp_cmd->data_out_desc_cnt + srp_cmd->data_in_desc_cnt)) {
969 			pr_err("received unsupported SRP_CMD request"
970 			       " type (%u out + %u in != %u / %zu)\n",
971 			       srp_cmd->data_out_desc_cnt,
972 			       srp_cmd->data_in_desc_cnt,
973 			       be32_to_cpu(idb->table_desc.len),
974 			       sizeof(struct srp_direct_buf));
975 			return -EINVAL;
976 		}
977 
978 		*data_len = be32_to_cpu(idb->len);
979 		return srpt_alloc_rw_ctxs(ioctx, idb->desc_list, nbufs,
980 				sg, sg_cnt);
981 	} else {
982 		*data_len = 0;
983 		return 0;
984 	}
985 }
986 
987 /**
988  * srpt_init_ch_qp() - Initialize queue pair attributes.
989  *
990  * Initialized the attributes of queue pair 'qp' by allowing local write,
991  * remote read and remote write. Also transitions 'qp' to state IB_QPS_INIT.
992  */
993 static int srpt_init_ch_qp(struct srpt_rdma_ch *ch, struct ib_qp *qp)
994 {
995 	struct ib_qp_attr *attr;
996 	int ret;
997 
998 	attr = kzalloc(sizeof(*attr), GFP_KERNEL);
999 	if (!attr)
1000 		return -ENOMEM;
1001 
1002 	attr->qp_state = IB_QPS_INIT;
1003 	attr->qp_access_flags = IB_ACCESS_LOCAL_WRITE | IB_ACCESS_REMOTE_READ |
1004 	    IB_ACCESS_REMOTE_WRITE;
1005 	attr->port_num = ch->sport->port;
1006 	attr->pkey_index = 0;
1007 
1008 	ret = ib_modify_qp(qp, attr,
1009 			   IB_QP_STATE | IB_QP_ACCESS_FLAGS | IB_QP_PORT |
1010 			   IB_QP_PKEY_INDEX);
1011 
1012 	kfree(attr);
1013 	return ret;
1014 }
1015 
1016 /**
1017  * srpt_ch_qp_rtr() - Change the state of a channel to 'ready to receive' (RTR).
1018  * @ch: channel of the queue pair.
1019  * @qp: queue pair to change the state of.
1020  *
1021  * Returns zero upon success and a negative value upon failure.
1022  *
1023  * Note: currently a struct ib_qp_attr takes 136 bytes on a 64-bit system.
1024  * If this structure ever becomes larger, it might be necessary to allocate
1025  * it dynamically instead of on the stack.
1026  */
1027 static int srpt_ch_qp_rtr(struct srpt_rdma_ch *ch, struct ib_qp *qp)
1028 {
1029 	struct ib_qp_attr qp_attr;
1030 	int attr_mask;
1031 	int ret;
1032 
1033 	qp_attr.qp_state = IB_QPS_RTR;
1034 	ret = ib_cm_init_qp_attr(ch->cm_id, &qp_attr, &attr_mask);
1035 	if (ret)
1036 		goto out;
1037 
1038 	qp_attr.max_dest_rd_atomic = 4;
1039 
1040 	ret = ib_modify_qp(qp, &qp_attr, attr_mask);
1041 
1042 out:
1043 	return ret;
1044 }
1045 
1046 /**
1047  * srpt_ch_qp_rts() - Change the state of a channel to 'ready to send' (RTS).
1048  * @ch: channel of the queue pair.
1049  * @qp: queue pair to change the state of.
1050  *
1051  * Returns zero upon success and a negative value upon failure.
1052  *
1053  * Note: currently a struct ib_qp_attr takes 136 bytes on a 64-bit system.
1054  * If this structure ever becomes larger, it might be necessary to allocate
1055  * it dynamically instead of on the stack.
1056  */
1057 static int srpt_ch_qp_rts(struct srpt_rdma_ch *ch, struct ib_qp *qp)
1058 {
1059 	struct ib_qp_attr qp_attr;
1060 	int attr_mask;
1061 	int ret;
1062 
1063 	qp_attr.qp_state = IB_QPS_RTS;
1064 	ret = ib_cm_init_qp_attr(ch->cm_id, &qp_attr, &attr_mask);
1065 	if (ret)
1066 		goto out;
1067 
1068 	qp_attr.max_rd_atomic = 4;
1069 
1070 	ret = ib_modify_qp(qp, &qp_attr, attr_mask);
1071 
1072 out:
1073 	return ret;
1074 }
1075 
1076 /**
1077  * srpt_ch_qp_err() - Set the channel queue pair state to 'error'.
1078  */
1079 static int srpt_ch_qp_err(struct srpt_rdma_ch *ch)
1080 {
1081 	struct ib_qp_attr qp_attr;
1082 
1083 	qp_attr.qp_state = IB_QPS_ERR;
1084 	return ib_modify_qp(ch->qp, &qp_attr, IB_QP_STATE);
1085 }
1086 
1087 /**
1088  * srpt_get_send_ioctx() - Obtain an I/O context for sending to the initiator.
1089  */
1090 static struct srpt_send_ioctx *srpt_get_send_ioctx(struct srpt_rdma_ch *ch)
1091 {
1092 	struct srpt_send_ioctx *ioctx;
1093 	unsigned long flags;
1094 
1095 	BUG_ON(!ch);
1096 
1097 	ioctx = NULL;
1098 	spin_lock_irqsave(&ch->spinlock, flags);
1099 	if (!list_empty(&ch->free_list)) {
1100 		ioctx = list_first_entry(&ch->free_list,
1101 					 struct srpt_send_ioctx, free_list);
1102 		list_del(&ioctx->free_list);
1103 	}
1104 	spin_unlock_irqrestore(&ch->spinlock, flags);
1105 
1106 	if (!ioctx)
1107 		return ioctx;
1108 
1109 	BUG_ON(ioctx->ch != ch);
1110 	spin_lock_init(&ioctx->spinlock);
1111 	ioctx->state = SRPT_STATE_NEW;
1112 	ioctx->n_rdma = 0;
1113 	ioctx->n_rw_ctx = 0;
1114 	init_completion(&ioctx->tx_done);
1115 	ioctx->queue_status_only = false;
1116 	/*
1117 	 * transport_init_se_cmd() does not initialize all fields, so do it
1118 	 * here.
1119 	 */
1120 	memset(&ioctx->cmd, 0, sizeof(ioctx->cmd));
1121 	memset(&ioctx->sense_data, 0, sizeof(ioctx->sense_data));
1122 
1123 	return ioctx;
1124 }
1125 
1126 /**
1127  * srpt_abort_cmd() - Abort a SCSI command.
1128  * @ioctx:   I/O context associated with the SCSI command.
1129  * @context: Preferred execution context.
1130  */
1131 static int srpt_abort_cmd(struct srpt_send_ioctx *ioctx)
1132 {
1133 	enum srpt_command_state state;
1134 	unsigned long flags;
1135 
1136 	BUG_ON(!ioctx);
1137 
1138 	/*
1139 	 * If the command is in a state where the target core is waiting for
1140 	 * the ib_srpt driver, change the state to the next state.
1141 	 */
1142 
1143 	spin_lock_irqsave(&ioctx->spinlock, flags);
1144 	state = ioctx->state;
1145 	switch (state) {
1146 	case SRPT_STATE_NEED_DATA:
1147 		ioctx->state = SRPT_STATE_DATA_IN;
1148 		break;
1149 	case SRPT_STATE_CMD_RSP_SENT:
1150 	case SRPT_STATE_MGMT_RSP_SENT:
1151 		ioctx->state = SRPT_STATE_DONE;
1152 		break;
1153 	default:
1154 		WARN_ONCE(true, "%s: unexpected I/O context state %d\n",
1155 			  __func__, state);
1156 		break;
1157 	}
1158 	spin_unlock_irqrestore(&ioctx->spinlock, flags);
1159 
1160 	pr_debug("Aborting cmd with state %d -> %d and tag %lld\n", state,
1161 		 ioctx->state, ioctx->cmd.tag);
1162 
1163 	switch (state) {
1164 	case SRPT_STATE_NEW:
1165 	case SRPT_STATE_DATA_IN:
1166 	case SRPT_STATE_MGMT:
1167 	case SRPT_STATE_DONE:
1168 		/*
1169 		 * Do nothing - defer abort processing until
1170 		 * srpt_queue_response() is invoked.
1171 		 */
1172 		break;
1173 	case SRPT_STATE_NEED_DATA:
1174 		pr_debug("tag %#llx: RDMA read error\n", ioctx->cmd.tag);
1175 		transport_generic_request_failure(&ioctx->cmd,
1176 					TCM_CHECK_CONDITION_ABORT_CMD);
1177 		break;
1178 	case SRPT_STATE_CMD_RSP_SENT:
1179 		/*
1180 		 * SRP_RSP sending failed or the SRP_RSP send completion has
1181 		 * not been received in time.
1182 		 */
1183 		transport_generic_free_cmd(&ioctx->cmd, 0);
1184 		break;
1185 	case SRPT_STATE_MGMT_RSP_SENT:
1186 		transport_generic_free_cmd(&ioctx->cmd, 0);
1187 		break;
1188 	default:
1189 		WARN(1, "Unexpected command state (%d)", state);
1190 		break;
1191 	}
1192 
1193 	return state;
1194 }
1195 
1196 /**
1197  * XXX: what is now target_execute_cmd used to be asynchronous, and unmapping
1198  * the data that has been transferred via IB RDMA had to be postponed until the
1199  * check_stop_free() callback.  None of this is necessary anymore and needs to
1200  * be cleaned up.
1201  */
1202 static void srpt_rdma_read_done(struct ib_cq *cq, struct ib_wc *wc)
1203 {
1204 	struct srpt_rdma_ch *ch = cq->cq_context;
1205 	struct srpt_send_ioctx *ioctx =
1206 		container_of(wc->wr_cqe, struct srpt_send_ioctx, rdma_cqe);
1207 
1208 	WARN_ON(ioctx->n_rdma <= 0);
1209 	atomic_add(ioctx->n_rdma, &ch->sq_wr_avail);
1210 	ioctx->n_rdma = 0;
1211 
1212 	if (unlikely(wc->status != IB_WC_SUCCESS)) {
1213 		pr_info("RDMA_READ for ioctx 0x%p failed with status %d\n",
1214 			ioctx, wc->status);
1215 		srpt_abort_cmd(ioctx);
1216 		return;
1217 	}
1218 
1219 	if (srpt_test_and_set_cmd_state(ioctx, SRPT_STATE_NEED_DATA,
1220 					SRPT_STATE_DATA_IN))
1221 		target_execute_cmd(&ioctx->cmd);
1222 	else
1223 		pr_err("%s[%d]: wrong state = %d\n", __func__,
1224 		       __LINE__, srpt_get_cmd_state(ioctx));
1225 }
1226 
1227 /**
1228  * srpt_build_cmd_rsp() - Build an SRP_RSP response.
1229  * @ch: RDMA channel through which the request has been received.
1230  * @ioctx: I/O context associated with the SRP_CMD request. The response will
1231  *   be built in the buffer ioctx->buf points at and hence this function will
1232  *   overwrite the request data.
1233  * @tag: tag of the request for which this response is being generated.
1234  * @status: value for the STATUS field of the SRP_RSP information unit.
1235  *
1236  * Returns the size in bytes of the SRP_RSP response.
1237  *
1238  * An SRP_RSP response contains a SCSI status or service response. See also
1239  * section 6.9 in the SRP r16a document for the format of an SRP_RSP
1240  * response. See also SPC-2 for more information about sense data.
1241  */
1242 static int srpt_build_cmd_rsp(struct srpt_rdma_ch *ch,
1243 			      struct srpt_send_ioctx *ioctx, u64 tag,
1244 			      int status)
1245 {
1246 	struct srp_rsp *srp_rsp;
1247 	const u8 *sense_data;
1248 	int sense_data_len, max_sense_len;
1249 
1250 	/*
1251 	 * The lowest bit of all SAM-3 status codes is zero (see also
1252 	 * paragraph 5.3 in SAM-3).
1253 	 */
1254 	WARN_ON(status & 1);
1255 
1256 	srp_rsp = ioctx->ioctx.buf;
1257 	BUG_ON(!srp_rsp);
1258 
1259 	sense_data = ioctx->sense_data;
1260 	sense_data_len = ioctx->cmd.scsi_sense_length;
1261 	WARN_ON(sense_data_len > sizeof(ioctx->sense_data));
1262 
1263 	memset(srp_rsp, 0, sizeof(*srp_rsp));
1264 	srp_rsp->opcode = SRP_RSP;
1265 	srp_rsp->req_lim_delta =
1266 		cpu_to_be32(1 + atomic_xchg(&ch->req_lim_delta, 0));
1267 	srp_rsp->tag = tag;
1268 	srp_rsp->status = status;
1269 
1270 	if (sense_data_len) {
1271 		BUILD_BUG_ON(MIN_MAX_RSP_SIZE <= sizeof(*srp_rsp));
1272 		max_sense_len = ch->max_ti_iu_len - sizeof(*srp_rsp);
1273 		if (sense_data_len > max_sense_len) {
1274 			pr_warn("truncated sense data from %d to %d"
1275 				" bytes\n", sense_data_len, max_sense_len);
1276 			sense_data_len = max_sense_len;
1277 		}
1278 
1279 		srp_rsp->flags |= SRP_RSP_FLAG_SNSVALID;
1280 		srp_rsp->sense_data_len = cpu_to_be32(sense_data_len);
1281 		memcpy(srp_rsp + 1, sense_data, sense_data_len);
1282 	}
1283 
1284 	return sizeof(*srp_rsp) + sense_data_len;
1285 }
1286 
1287 /**
1288  * srpt_build_tskmgmt_rsp() - Build a task management response.
1289  * @ch:       RDMA channel through which the request has been received.
1290  * @ioctx:    I/O context in which the SRP_RSP response will be built.
1291  * @rsp_code: RSP_CODE that will be stored in the response.
1292  * @tag:      Tag of the request for which this response is being generated.
1293  *
1294  * Returns the size in bytes of the SRP_RSP response.
1295  *
1296  * An SRP_RSP response contains a SCSI status or service response. See also
1297  * section 6.9 in the SRP r16a document for the format of an SRP_RSP
1298  * response.
1299  */
1300 static int srpt_build_tskmgmt_rsp(struct srpt_rdma_ch *ch,
1301 				  struct srpt_send_ioctx *ioctx,
1302 				  u8 rsp_code, u64 tag)
1303 {
1304 	struct srp_rsp *srp_rsp;
1305 	int resp_data_len;
1306 	int resp_len;
1307 
1308 	resp_data_len = 4;
1309 	resp_len = sizeof(*srp_rsp) + resp_data_len;
1310 
1311 	srp_rsp = ioctx->ioctx.buf;
1312 	BUG_ON(!srp_rsp);
1313 	memset(srp_rsp, 0, sizeof(*srp_rsp));
1314 
1315 	srp_rsp->opcode = SRP_RSP;
1316 	srp_rsp->req_lim_delta =
1317 		cpu_to_be32(1 + atomic_xchg(&ch->req_lim_delta, 0));
1318 	srp_rsp->tag = tag;
1319 
1320 	srp_rsp->flags |= SRP_RSP_FLAG_RSPVALID;
1321 	srp_rsp->resp_data_len = cpu_to_be32(resp_data_len);
1322 	srp_rsp->data[3] = rsp_code;
1323 
1324 	return resp_len;
1325 }
1326 
1327 static int srpt_check_stop_free(struct se_cmd *cmd)
1328 {
1329 	struct srpt_send_ioctx *ioctx = container_of(cmd,
1330 				struct srpt_send_ioctx, cmd);
1331 
1332 	return target_put_sess_cmd(&ioctx->cmd);
1333 }
1334 
1335 /**
1336  * srpt_handle_cmd() - Process SRP_CMD.
1337  */
1338 static void srpt_handle_cmd(struct srpt_rdma_ch *ch,
1339 			    struct srpt_recv_ioctx *recv_ioctx,
1340 			    struct srpt_send_ioctx *send_ioctx)
1341 {
1342 	struct se_cmd *cmd;
1343 	struct srp_cmd *srp_cmd;
1344 	struct scatterlist *sg = NULL;
1345 	unsigned sg_cnt = 0;
1346 	u64 data_len;
1347 	enum dma_data_direction dir;
1348 	int rc;
1349 
1350 	BUG_ON(!send_ioctx);
1351 
1352 	srp_cmd = recv_ioctx->ioctx.buf;
1353 	cmd = &send_ioctx->cmd;
1354 	cmd->tag = srp_cmd->tag;
1355 
1356 	switch (srp_cmd->task_attr) {
1357 	case SRP_CMD_SIMPLE_Q:
1358 		cmd->sam_task_attr = TCM_SIMPLE_TAG;
1359 		break;
1360 	case SRP_CMD_ORDERED_Q:
1361 	default:
1362 		cmd->sam_task_attr = TCM_ORDERED_TAG;
1363 		break;
1364 	case SRP_CMD_HEAD_OF_Q:
1365 		cmd->sam_task_attr = TCM_HEAD_TAG;
1366 		break;
1367 	case SRP_CMD_ACA:
1368 		cmd->sam_task_attr = TCM_ACA_TAG;
1369 		break;
1370 	}
1371 
1372 	rc = srpt_get_desc_tbl(send_ioctx, srp_cmd, &dir, &sg, &sg_cnt,
1373 			&data_len);
1374 	if (rc) {
1375 		if (rc != -EAGAIN) {
1376 			pr_err("0x%llx: parsing SRP descriptor table failed.\n",
1377 			       srp_cmd->tag);
1378 		}
1379 		goto release_ioctx;
1380 	}
1381 
1382 	rc = target_submit_cmd_map_sgls(cmd, ch->sess, srp_cmd->cdb,
1383 			       &send_ioctx->sense_data[0],
1384 			       scsilun_to_int(&srp_cmd->lun), data_len,
1385 			       TCM_SIMPLE_TAG, dir, TARGET_SCF_ACK_KREF,
1386 			       sg, sg_cnt, NULL, 0, NULL, 0);
1387 	if (rc != 0) {
1388 		pr_debug("target_submit_cmd() returned %d for tag %#llx\n", rc,
1389 			 srp_cmd->tag);
1390 		goto release_ioctx;
1391 	}
1392 	return;
1393 
1394 release_ioctx:
1395 	send_ioctx->state = SRPT_STATE_DONE;
1396 	srpt_release_cmd(cmd);
1397 }
1398 
1399 static int srp_tmr_to_tcm(int fn)
1400 {
1401 	switch (fn) {
1402 	case SRP_TSK_ABORT_TASK:
1403 		return TMR_ABORT_TASK;
1404 	case SRP_TSK_ABORT_TASK_SET:
1405 		return TMR_ABORT_TASK_SET;
1406 	case SRP_TSK_CLEAR_TASK_SET:
1407 		return TMR_CLEAR_TASK_SET;
1408 	case SRP_TSK_LUN_RESET:
1409 		return TMR_LUN_RESET;
1410 	case SRP_TSK_CLEAR_ACA:
1411 		return TMR_CLEAR_ACA;
1412 	default:
1413 		return -1;
1414 	}
1415 }
1416 
1417 /**
1418  * srpt_handle_tsk_mgmt() - Process an SRP_TSK_MGMT information unit.
1419  *
1420  * Returns 0 if and only if the request will be processed by the target core.
1421  *
1422  * For more information about SRP_TSK_MGMT information units, see also section
1423  * 6.7 in the SRP r16a document.
1424  */
1425 static void srpt_handle_tsk_mgmt(struct srpt_rdma_ch *ch,
1426 				 struct srpt_recv_ioctx *recv_ioctx,
1427 				 struct srpt_send_ioctx *send_ioctx)
1428 {
1429 	struct srp_tsk_mgmt *srp_tsk;
1430 	struct se_cmd *cmd;
1431 	struct se_session *sess = ch->sess;
1432 	int tcm_tmr;
1433 	int rc;
1434 
1435 	BUG_ON(!send_ioctx);
1436 
1437 	srp_tsk = recv_ioctx->ioctx.buf;
1438 	cmd = &send_ioctx->cmd;
1439 
1440 	pr_debug("recv tsk_mgmt fn %d for task_tag %lld and cmd tag %lld"
1441 		 " cm_id %p sess %p\n", srp_tsk->tsk_mgmt_func,
1442 		 srp_tsk->task_tag, srp_tsk->tag, ch->cm_id, ch->sess);
1443 
1444 	srpt_set_cmd_state(send_ioctx, SRPT_STATE_MGMT);
1445 	send_ioctx->cmd.tag = srp_tsk->tag;
1446 	tcm_tmr = srp_tmr_to_tcm(srp_tsk->tsk_mgmt_func);
1447 	rc = target_submit_tmr(&send_ioctx->cmd, sess, NULL,
1448 			       scsilun_to_int(&srp_tsk->lun), srp_tsk, tcm_tmr,
1449 			       GFP_KERNEL, srp_tsk->task_tag,
1450 			       TARGET_SCF_ACK_KREF);
1451 	if (rc != 0) {
1452 		send_ioctx->cmd.se_tmr_req->response = TMR_FUNCTION_REJECTED;
1453 		goto fail;
1454 	}
1455 	return;
1456 fail:
1457 	transport_send_check_condition_and_sense(cmd, 0, 0); // XXX:
1458 }
1459 
1460 /**
1461  * srpt_handle_new_iu() - Process a newly received information unit.
1462  * @ch:    RDMA channel through which the information unit has been received.
1463  * @ioctx: SRPT I/O context associated with the information unit.
1464  */
1465 static void srpt_handle_new_iu(struct srpt_rdma_ch *ch,
1466 			       struct srpt_recv_ioctx *recv_ioctx,
1467 			       struct srpt_send_ioctx *send_ioctx)
1468 {
1469 	struct srp_cmd *srp_cmd;
1470 
1471 	BUG_ON(!ch);
1472 	BUG_ON(!recv_ioctx);
1473 
1474 	ib_dma_sync_single_for_cpu(ch->sport->sdev->device,
1475 				   recv_ioctx->ioctx.dma, srp_max_req_size,
1476 				   DMA_FROM_DEVICE);
1477 
1478 	if (unlikely(ch->state == CH_CONNECTING))
1479 		goto out_wait;
1480 
1481 	if (unlikely(ch->state != CH_LIVE))
1482 		return;
1483 
1484 	srp_cmd = recv_ioctx->ioctx.buf;
1485 	if (srp_cmd->opcode == SRP_CMD || srp_cmd->opcode == SRP_TSK_MGMT) {
1486 		if (!send_ioctx) {
1487 			if (!list_empty(&ch->cmd_wait_list))
1488 				goto out_wait;
1489 			send_ioctx = srpt_get_send_ioctx(ch);
1490 		}
1491 		if (unlikely(!send_ioctx))
1492 			goto out_wait;
1493 	}
1494 
1495 	switch (srp_cmd->opcode) {
1496 	case SRP_CMD:
1497 		srpt_handle_cmd(ch, recv_ioctx, send_ioctx);
1498 		break;
1499 	case SRP_TSK_MGMT:
1500 		srpt_handle_tsk_mgmt(ch, recv_ioctx, send_ioctx);
1501 		break;
1502 	case SRP_I_LOGOUT:
1503 		pr_err("Not yet implemented: SRP_I_LOGOUT\n");
1504 		break;
1505 	case SRP_CRED_RSP:
1506 		pr_debug("received SRP_CRED_RSP\n");
1507 		break;
1508 	case SRP_AER_RSP:
1509 		pr_debug("received SRP_AER_RSP\n");
1510 		break;
1511 	case SRP_RSP:
1512 		pr_err("Received SRP_RSP\n");
1513 		break;
1514 	default:
1515 		pr_err("received IU with unknown opcode 0x%x\n",
1516 		       srp_cmd->opcode);
1517 		break;
1518 	}
1519 
1520 	srpt_post_recv(ch->sport->sdev, recv_ioctx);
1521 	return;
1522 
1523 out_wait:
1524 	list_add_tail(&recv_ioctx->wait_list, &ch->cmd_wait_list);
1525 }
1526 
1527 static void srpt_recv_done(struct ib_cq *cq, struct ib_wc *wc)
1528 {
1529 	struct srpt_rdma_ch *ch = cq->cq_context;
1530 	struct srpt_recv_ioctx *ioctx =
1531 		container_of(wc->wr_cqe, struct srpt_recv_ioctx, ioctx.cqe);
1532 
1533 	if (wc->status == IB_WC_SUCCESS) {
1534 		int req_lim;
1535 
1536 		req_lim = atomic_dec_return(&ch->req_lim);
1537 		if (unlikely(req_lim < 0))
1538 			pr_err("req_lim = %d < 0\n", req_lim);
1539 		srpt_handle_new_iu(ch, ioctx, NULL);
1540 	} else {
1541 		pr_info("receiving failed for ioctx %p with status %d\n",
1542 			ioctx, wc->status);
1543 	}
1544 }
1545 
1546 /*
1547  * This function must be called from the context in which RDMA completions are
1548  * processed because it accesses the wait list without protection against
1549  * access from other threads.
1550  */
1551 static void srpt_process_wait_list(struct srpt_rdma_ch *ch)
1552 {
1553 	struct srpt_send_ioctx *ioctx;
1554 
1555 	while (!list_empty(&ch->cmd_wait_list) &&
1556 	       ch->state >= CH_LIVE &&
1557 	       (ioctx = srpt_get_send_ioctx(ch)) != NULL) {
1558 		struct srpt_recv_ioctx *recv_ioctx;
1559 
1560 		recv_ioctx = list_first_entry(&ch->cmd_wait_list,
1561 					      struct srpt_recv_ioctx,
1562 					      wait_list);
1563 		list_del(&recv_ioctx->wait_list);
1564 		srpt_handle_new_iu(ch, recv_ioctx, ioctx);
1565 	}
1566 }
1567 
1568 /**
1569  * Note: Although this has not yet been observed during tests, at least in
1570  * theory it is possible that the srpt_get_send_ioctx() call invoked by
1571  * srpt_handle_new_iu() fails. This is possible because the req_lim_delta
1572  * value in each response is set to one, and it is possible that this response
1573  * makes the initiator send a new request before the send completion for that
1574  * response has been processed. This could e.g. happen if the call to
1575  * srpt_put_send_iotcx() is delayed because of a higher priority interrupt or
1576  * if IB retransmission causes generation of the send completion to be
1577  * delayed. Incoming information units for which srpt_get_send_ioctx() fails
1578  * are queued on cmd_wait_list. The code below processes these delayed
1579  * requests one at a time.
1580  */
1581 static void srpt_send_done(struct ib_cq *cq, struct ib_wc *wc)
1582 {
1583 	struct srpt_rdma_ch *ch = cq->cq_context;
1584 	struct srpt_send_ioctx *ioctx =
1585 		container_of(wc->wr_cqe, struct srpt_send_ioctx, ioctx.cqe);
1586 	enum srpt_command_state state;
1587 
1588 	state = srpt_set_cmd_state(ioctx, SRPT_STATE_DONE);
1589 
1590 	WARN_ON(state != SRPT_STATE_CMD_RSP_SENT &&
1591 		state != SRPT_STATE_MGMT_RSP_SENT);
1592 
1593 	atomic_add(1 + ioctx->n_rdma, &ch->sq_wr_avail);
1594 
1595 	if (wc->status != IB_WC_SUCCESS)
1596 		pr_info("sending response for ioctx 0x%p failed"
1597 			" with status %d\n", ioctx, wc->status);
1598 
1599 	if (state != SRPT_STATE_DONE) {
1600 		transport_generic_free_cmd(&ioctx->cmd, 0);
1601 	} else {
1602 		pr_err("IB completion has been received too late for"
1603 		       " wr_id = %u.\n", ioctx->ioctx.index);
1604 	}
1605 
1606 	srpt_process_wait_list(ch);
1607 }
1608 
1609 /**
1610  * srpt_create_ch_ib() - Create receive and send completion queues.
1611  */
1612 static int srpt_create_ch_ib(struct srpt_rdma_ch *ch)
1613 {
1614 	struct ib_qp_init_attr *qp_init;
1615 	struct srpt_port *sport = ch->sport;
1616 	struct srpt_device *sdev = sport->sdev;
1617 	const struct ib_device_attr *attrs = &sdev->device->attrs;
1618 	u32 srp_sq_size = sport->port_attrib.srp_sq_size;
1619 	int ret;
1620 
1621 	WARN_ON(ch->rq_size < 1);
1622 
1623 	ret = -ENOMEM;
1624 	qp_init = kzalloc(sizeof(*qp_init), GFP_KERNEL);
1625 	if (!qp_init)
1626 		goto out;
1627 
1628 retry:
1629 	ch->cq = ib_alloc_cq(sdev->device, ch, ch->rq_size + srp_sq_size,
1630 			0 /* XXX: spread CQs */, IB_POLL_WORKQUEUE);
1631 	if (IS_ERR(ch->cq)) {
1632 		ret = PTR_ERR(ch->cq);
1633 		pr_err("failed to create CQ cqe= %d ret= %d\n",
1634 		       ch->rq_size + srp_sq_size, ret);
1635 		goto out;
1636 	}
1637 
1638 	qp_init->qp_context = (void *)ch;
1639 	qp_init->event_handler
1640 		= (void(*)(struct ib_event *, void*))srpt_qp_event;
1641 	qp_init->send_cq = ch->cq;
1642 	qp_init->recv_cq = ch->cq;
1643 	qp_init->srq = sdev->srq;
1644 	qp_init->sq_sig_type = IB_SIGNAL_REQ_WR;
1645 	qp_init->qp_type = IB_QPT_RC;
1646 	/*
1647 	 * We divide up our send queue size into half SEND WRs to send the
1648 	 * completions, and half R/W contexts to actually do the RDMA
1649 	 * READ/WRITE transfers.  Note that we need to allocate CQ slots for
1650 	 * both both, as RDMA contexts will also post completions for the
1651 	 * RDMA READ case.
1652 	 */
1653 	qp_init->cap.max_send_wr = srp_sq_size / 2;
1654 	qp_init->cap.max_rdma_ctxs = srp_sq_size / 2;
1655 	qp_init->cap.max_send_sge = min(attrs->max_sge, SRPT_MAX_SG_PER_WQE);
1656 	qp_init->port_num = ch->sport->port;
1657 
1658 	ch->qp = ib_create_qp(sdev->pd, qp_init);
1659 	if (IS_ERR(ch->qp)) {
1660 		ret = PTR_ERR(ch->qp);
1661 		if (ret == -ENOMEM) {
1662 			srp_sq_size /= 2;
1663 			if (srp_sq_size >= MIN_SRPT_SQ_SIZE) {
1664 				ib_destroy_cq(ch->cq);
1665 				goto retry;
1666 			}
1667 		}
1668 		pr_err("failed to create_qp ret= %d\n", ret);
1669 		goto err_destroy_cq;
1670 	}
1671 
1672 	atomic_set(&ch->sq_wr_avail, qp_init->cap.max_send_wr);
1673 
1674 	pr_debug("%s: max_cqe= %d max_sge= %d sq_size = %d cm_id= %p\n",
1675 		 __func__, ch->cq->cqe, qp_init->cap.max_send_sge,
1676 		 qp_init->cap.max_send_wr, ch->cm_id);
1677 
1678 	ret = srpt_init_ch_qp(ch, ch->qp);
1679 	if (ret)
1680 		goto err_destroy_qp;
1681 
1682 out:
1683 	kfree(qp_init);
1684 	return ret;
1685 
1686 err_destroy_qp:
1687 	ib_destroy_qp(ch->qp);
1688 err_destroy_cq:
1689 	ib_free_cq(ch->cq);
1690 	goto out;
1691 }
1692 
1693 static void srpt_destroy_ch_ib(struct srpt_rdma_ch *ch)
1694 {
1695 	ib_destroy_qp(ch->qp);
1696 	ib_free_cq(ch->cq);
1697 }
1698 
1699 /**
1700  * srpt_close_ch() - Close an RDMA channel.
1701  *
1702  * Make sure all resources associated with the channel will be deallocated at
1703  * an appropriate time.
1704  *
1705  * Returns true if and only if the channel state has been modified into
1706  * CH_DRAINING.
1707  */
1708 static bool srpt_close_ch(struct srpt_rdma_ch *ch)
1709 {
1710 	int ret;
1711 
1712 	if (!srpt_set_ch_state(ch, CH_DRAINING)) {
1713 		pr_debug("%s-%d: already closed\n", ch->sess_name,
1714 			 ch->qp->qp_num);
1715 		return false;
1716 	}
1717 
1718 	kref_get(&ch->kref);
1719 
1720 	ret = srpt_ch_qp_err(ch);
1721 	if (ret < 0)
1722 		pr_err("%s-%d: changing queue pair into error state failed: %d\n",
1723 		       ch->sess_name, ch->qp->qp_num, ret);
1724 
1725 	pr_debug("%s-%d: queued zerolength write\n", ch->sess_name,
1726 		 ch->qp->qp_num);
1727 	ret = srpt_zerolength_write(ch);
1728 	if (ret < 0) {
1729 		pr_err("%s-%d: queuing zero-length write failed: %d\n",
1730 		       ch->sess_name, ch->qp->qp_num, ret);
1731 		if (srpt_set_ch_state(ch, CH_DISCONNECTED))
1732 			schedule_work(&ch->release_work);
1733 		else
1734 			WARN_ON_ONCE(true);
1735 	}
1736 
1737 	kref_put(&ch->kref, srpt_free_ch);
1738 
1739 	return true;
1740 }
1741 
1742 /*
1743  * Change the channel state into CH_DISCONNECTING. If a channel has not yet
1744  * reached the connected state, close it. If a channel is in the connected
1745  * state, send a DREQ. If a DREQ has been received, send a DREP. Note: it is
1746  * the responsibility of the caller to ensure that this function is not
1747  * invoked concurrently with the code that accepts a connection. This means
1748  * that this function must either be invoked from inside a CM callback
1749  * function or that it must be invoked with the srpt_port.mutex held.
1750  */
1751 static int srpt_disconnect_ch(struct srpt_rdma_ch *ch)
1752 {
1753 	int ret;
1754 
1755 	if (!srpt_set_ch_state(ch, CH_DISCONNECTING))
1756 		return -ENOTCONN;
1757 
1758 	ret = ib_send_cm_dreq(ch->cm_id, NULL, 0);
1759 	if (ret < 0)
1760 		ret = ib_send_cm_drep(ch->cm_id, NULL, 0);
1761 
1762 	if (ret < 0 && srpt_close_ch(ch))
1763 		ret = 0;
1764 
1765 	return ret;
1766 }
1767 
1768 static void __srpt_close_all_ch(struct srpt_device *sdev)
1769 {
1770 	struct srpt_rdma_ch *ch;
1771 
1772 	lockdep_assert_held(&sdev->mutex);
1773 
1774 	list_for_each_entry(ch, &sdev->rch_list, list) {
1775 		if (srpt_disconnect_ch(ch) >= 0)
1776 			pr_info("Closing channel %s-%d because target %s has been disabled\n",
1777 				ch->sess_name, ch->qp->qp_num,
1778 				sdev->device->name);
1779 		srpt_close_ch(ch);
1780 	}
1781 }
1782 
1783 static void srpt_free_ch(struct kref *kref)
1784 {
1785 	struct srpt_rdma_ch *ch = container_of(kref, struct srpt_rdma_ch, kref);
1786 
1787 	kfree(ch);
1788 }
1789 
1790 static void srpt_release_channel_work(struct work_struct *w)
1791 {
1792 	struct srpt_rdma_ch *ch;
1793 	struct srpt_device *sdev;
1794 	struct se_session *se_sess;
1795 
1796 	ch = container_of(w, struct srpt_rdma_ch, release_work);
1797 	pr_debug("%s: %s-%d; release_done = %p\n", __func__, ch->sess_name,
1798 		 ch->qp->qp_num, ch->release_done);
1799 
1800 	sdev = ch->sport->sdev;
1801 	BUG_ON(!sdev);
1802 
1803 	se_sess = ch->sess;
1804 	BUG_ON(!se_sess);
1805 
1806 	target_sess_cmd_list_set_waiting(se_sess);
1807 	target_wait_for_sess_cmds(se_sess);
1808 
1809 	transport_deregister_session_configfs(se_sess);
1810 	transport_deregister_session(se_sess);
1811 	ch->sess = NULL;
1812 
1813 	ib_destroy_cm_id(ch->cm_id);
1814 
1815 	srpt_destroy_ch_ib(ch);
1816 
1817 	srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_ring,
1818 			     ch->sport->sdev, ch->rq_size,
1819 			     ch->rsp_size, DMA_TO_DEVICE);
1820 
1821 	mutex_lock(&sdev->mutex);
1822 	list_del_init(&ch->list);
1823 	if (ch->release_done)
1824 		complete(ch->release_done);
1825 	mutex_unlock(&sdev->mutex);
1826 
1827 	wake_up(&sdev->ch_releaseQ);
1828 
1829 	kref_put(&ch->kref, srpt_free_ch);
1830 }
1831 
1832 /**
1833  * srpt_cm_req_recv() - Process the event IB_CM_REQ_RECEIVED.
1834  *
1835  * Ownership of the cm_id is transferred to the target session if this
1836  * functions returns zero. Otherwise the caller remains the owner of cm_id.
1837  */
1838 static int srpt_cm_req_recv(struct ib_cm_id *cm_id,
1839 			    struct ib_cm_req_event_param *param,
1840 			    void *private_data)
1841 {
1842 	struct srpt_device *sdev = cm_id->context;
1843 	struct srpt_port *sport = &sdev->port[param->port - 1];
1844 	struct srp_login_req *req;
1845 	struct srp_login_rsp *rsp;
1846 	struct srp_login_rej *rej;
1847 	struct ib_cm_rep_param *rep_param;
1848 	struct srpt_rdma_ch *ch, *tmp_ch;
1849 	__be16 *guid;
1850 	u32 it_iu_len;
1851 	int i, ret = 0;
1852 
1853 	WARN_ON_ONCE(irqs_disabled());
1854 
1855 	if (WARN_ON(!sdev || !private_data))
1856 		return -EINVAL;
1857 
1858 	req = (struct srp_login_req *)private_data;
1859 
1860 	it_iu_len = be32_to_cpu(req->req_it_iu_len);
1861 
1862 	pr_info("Received SRP_LOGIN_REQ with i_port_id 0x%llx:0x%llx,"
1863 		" t_port_id 0x%llx:0x%llx and it_iu_len %d on port %d"
1864 		" (guid=0x%llx:0x%llx)\n",
1865 		be64_to_cpu(*(__be64 *)&req->initiator_port_id[0]),
1866 		be64_to_cpu(*(__be64 *)&req->initiator_port_id[8]),
1867 		be64_to_cpu(*(__be64 *)&req->target_port_id[0]),
1868 		be64_to_cpu(*(__be64 *)&req->target_port_id[8]),
1869 		it_iu_len,
1870 		param->port,
1871 		be64_to_cpu(*(__be64 *)&sdev->port[param->port - 1].gid.raw[0]),
1872 		be64_to_cpu(*(__be64 *)&sdev->port[param->port - 1].gid.raw[8]));
1873 
1874 	rsp = kzalloc(sizeof(*rsp), GFP_KERNEL);
1875 	rej = kzalloc(sizeof(*rej), GFP_KERNEL);
1876 	rep_param = kzalloc(sizeof(*rep_param), GFP_KERNEL);
1877 
1878 	if (!rsp || !rej || !rep_param) {
1879 		ret = -ENOMEM;
1880 		goto out;
1881 	}
1882 
1883 	if (it_iu_len > srp_max_req_size || it_iu_len < 64) {
1884 		rej->reason = cpu_to_be32(
1885 			      SRP_LOGIN_REJ_REQ_IT_IU_LENGTH_TOO_LARGE);
1886 		ret = -EINVAL;
1887 		pr_err("rejected SRP_LOGIN_REQ because its"
1888 		       " length (%d bytes) is out of range (%d .. %d)\n",
1889 		       it_iu_len, 64, srp_max_req_size);
1890 		goto reject;
1891 	}
1892 
1893 	if (!sport->enabled) {
1894 		rej->reason = cpu_to_be32(
1895 			      SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
1896 		ret = -EINVAL;
1897 		pr_err("rejected SRP_LOGIN_REQ because the target port"
1898 		       " has not yet been enabled\n");
1899 		goto reject;
1900 	}
1901 
1902 	if ((req->req_flags & SRP_MTCH_ACTION) == SRP_MULTICHAN_SINGLE) {
1903 		rsp->rsp_flags = SRP_LOGIN_RSP_MULTICHAN_NO_CHAN;
1904 
1905 		mutex_lock(&sdev->mutex);
1906 
1907 		list_for_each_entry_safe(ch, tmp_ch, &sdev->rch_list, list) {
1908 			if (!memcmp(ch->i_port_id, req->initiator_port_id, 16)
1909 			    && !memcmp(ch->t_port_id, req->target_port_id, 16)
1910 			    && param->port == ch->sport->port
1911 			    && param->listen_id == ch->sport->sdev->cm_id
1912 			    && ch->cm_id) {
1913 				if (srpt_disconnect_ch(ch) < 0)
1914 					continue;
1915 				pr_info("Relogin - closed existing channel %s\n",
1916 					ch->sess_name);
1917 				rsp->rsp_flags =
1918 					SRP_LOGIN_RSP_MULTICHAN_TERMINATED;
1919 			}
1920 		}
1921 
1922 		mutex_unlock(&sdev->mutex);
1923 
1924 	} else
1925 		rsp->rsp_flags = SRP_LOGIN_RSP_MULTICHAN_MAINTAINED;
1926 
1927 	if (*(__be64 *)req->target_port_id != cpu_to_be64(srpt_service_guid)
1928 	    || *(__be64 *)(req->target_port_id + 8) !=
1929 	       cpu_to_be64(srpt_service_guid)) {
1930 		rej->reason = cpu_to_be32(
1931 			      SRP_LOGIN_REJ_UNABLE_ASSOCIATE_CHANNEL);
1932 		ret = -ENOMEM;
1933 		pr_err("rejected SRP_LOGIN_REQ because it"
1934 		       " has an invalid target port identifier.\n");
1935 		goto reject;
1936 	}
1937 
1938 	ch = kzalloc(sizeof(*ch), GFP_KERNEL);
1939 	if (!ch) {
1940 		rej->reason = cpu_to_be32(
1941 			      SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
1942 		pr_err("rejected SRP_LOGIN_REQ because no memory.\n");
1943 		ret = -ENOMEM;
1944 		goto reject;
1945 	}
1946 
1947 	kref_init(&ch->kref);
1948 	ch->zw_cqe.done = srpt_zerolength_write_done;
1949 	INIT_WORK(&ch->release_work, srpt_release_channel_work);
1950 	memcpy(ch->i_port_id, req->initiator_port_id, 16);
1951 	memcpy(ch->t_port_id, req->target_port_id, 16);
1952 	ch->sport = &sdev->port[param->port - 1];
1953 	ch->cm_id = cm_id;
1954 	cm_id->context = ch;
1955 	/*
1956 	 * Avoid QUEUE_FULL conditions by limiting the number of buffers used
1957 	 * for the SRP protocol to the command queue size.
1958 	 */
1959 	ch->rq_size = SRPT_RQ_SIZE;
1960 	spin_lock_init(&ch->spinlock);
1961 	ch->state = CH_CONNECTING;
1962 	INIT_LIST_HEAD(&ch->cmd_wait_list);
1963 	ch->rsp_size = ch->sport->port_attrib.srp_max_rsp_size;
1964 
1965 	ch->ioctx_ring = (struct srpt_send_ioctx **)
1966 		srpt_alloc_ioctx_ring(ch->sport->sdev, ch->rq_size,
1967 				      sizeof(*ch->ioctx_ring[0]),
1968 				      ch->rsp_size, DMA_TO_DEVICE);
1969 	if (!ch->ioctx_ring)
1970 		goto free_ch;
1971 
1972 	INIT_LIST_HEAD(&ch->free_list);
1973 	for (i = 0; i < ch->rq_size; i++) {
1974 		ch->ioctx_ring[i]->ch = ch;
1975 		list_add_tail(&ch->ioctx_ring[i]->free_list, &ch->free_list);
1976 	}
1977 
1978 	ret = srpt_create_ch_ib(ch);
1979 	if (ret) {
1980 		rej->reason = cpu_to_be32(
1981 			      SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
1982 		pr_err("rejected SRP_LOGIN_REQ because creating"
1983 		       " a new RDMA channel failed.\n");
1984 		goto free_ring;
1985 	}
1986 
1987 	ret = srpt_ch_qp_rtr(ch, ch->qp);
1988 	if (ret) {
1989 		rej->reason = cpu_to_be32(SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
1990 		pr_err("rejected SRP_LOGIN_REQ because enabling"
1991 		       " RTR failed (error code = %d)\n", ret);
1992 		goto destroy_ib;
1993 	}
1994 
1995 	guid = (__be16 *)&param->primary_path->sgid.global.interface_id;
1996 	snprintf(ch->ini_guid, sizeof(ch->ini_guid), "%04x:%04x:%04x:%04x",
1997 		 be16_to_cpu(guid[0]), be16_to_cpu(guid[1]),
1998 		 be16_to_cpu(guid[2]), be16_to_cpu(guid[3]));
1999 	snprintf(ch->sess_name, sizeof(ch->sess_name), "0x%016llx%016llx",
2000 			be64_to_cpu(*(__be64 *)ch->i_port_id),
2001 			be64_to_cpu(*(__be64 *)(ch->i_port_id + 8)));
2002 
2003 	pr_debug("registering session %s\n", ch->sess_name);
2004 
2005 	if (sport->port_guid_tpg.se_tpg_wwn)
2006 		ch->sess = target_alloc_session(&sport->port_guid_tpg, 0, 0,
2007 						TARGET_PROT_NORMAL,
2008 						ch->ini_guid, ch, NULL);
2009 	if (sport->port_gid_tpg.se_tpg_wwn && IS_ERR_OR_NULL(ch->sess))
2010 		ch->sess = target_alloc_session(&sport->port_gid_tpg, 0, 0,
2011 					TARGET_PROT_NORMAL, ch->sess_name, ch,
2012 					NULL);
2013 	/* Retry without leading "0x" */
2014 	if (sport->port_gid_tpg.se_tpg_wwn && IS_ERR_OR_NULL(ch->sess))
2015 		ch->sess = target_alloc_session(&sport->port_gid_tpg, 0, 0,
2016 						TARGET_PROT_NORMAL,
2017 						ch->sess_name + 2, ch, NULL);
2018 	if (IS_ERR_OR_NULL(ch->sess)) {
2019 		pr_info("Rejected login because no ACL has been configured yet for initiator %s.\n",
2020 			ch->sess_name);
2021 		rej->reason = cpu_to_be32((PTR_ERR(ch->sess) == -ENOMEM) ?
2022 				SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES :
2023 				SRP_LOGIN_REJ_CHANNEL_LIMIT_REACHED);
2024 		goto destroy_ib;
2025 	}
2026 
2027 	pr_debug("Establish connection sess=%p name=%s cm_id=%p\n", ch->sess,
2028 		 ch->sess_name, ch->cm_id);
2029 
2030 	/* create srp_login_response */
2031 	rsp->opcode = SRP_LOGIN_RSP;
2032 	rsp->tag = req->tag;
2033 	rsp->max_it_iu_len = req->req_it_iu_len;
2034 	rsp->max_ti_iu_len = req->req_it_iu_len;
2035 	ch->max_ti_iu_len = it_iu_len;
2036 	rsp->buf_fmt = cpu_to_be16(SRP_BUF_FORMAT_DIRECT
2037 				   | SRP_BUF_FORMAT_INDIRECT);
2038 	rsp->req_lim_delta = cpu_to_be32(ch->rq_size);
2039 	atomic_set(&ch->req_lim, ch->rq_size);
2040 	atomic_set(&ch->req_lim_delta, 0);
2041 
2042 	/* create cm reply */
2043 	rep_param->qp_num = ch->qp->qp_num;
2044 	rep_param->private_data = (void *)rsp;
2045 	rep_param->private_data_len = sizeof(*rsp);
2046 	rep_param->rnr_retry_count = 7;
2047 	rep_param->flow_control = 1;
2048 	rep_param->failover_accepted = 0;
2049 	rep_param->srq = 1;
2050 	rep_param->responder_resources = 4;
2051 	rep_param->initiator_depth = 4;
2052 
2053 	ret = ib_send_cm_rep(cm_id, rep_param);
2054 	if (ret) {
2055 		pr_err("sending SRP_LOGIN_REQ response failed"
2056 		       " (error code = %d)\n", ret);
2057 		goto release_channel;
2058 	}
2059 
2060 	mutex_lock(&sdev->mutex);
2061 	list_add_tail(&ch->list, &sdev->rch_list);
2062 	mutex_unlock(&sdev->mutex);
2063 
2064 	goto out;
2065 
2066 release_channel:
2067 	srpt_disconnect_ch(ch);
2068 	transport_deregister_session_configfs(ch->sess);
2069 	transport_deregister_session(ch->sess);
2070 	ch->sess = NULL;
2071 
2072 destroy_ib:
2073 	srpt_destroy_ch_ib(ch);
2074 
2075 free_ring:
2076 	srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_ring,
2077 			     ch->sport->sdev, ch->rq_size,
2078 			     ch->rsp_size, DMA_TO_DEVICE);
2079 free_ch:
2080 	kfree(ch);
2081 
2082 reject:
2083 	rej->opcode = SRP_LOGIN_REJ;
2084 	rej->tag = req->tag;
2085 	rej->buf_fmt = cpu_to_be16(SRP_BUF_FORMAT_DIRECT
2086 				   | SRP_BUF_FORMAT_INDIRECT);
2087 
2088 	ib_send_cm_rej(cm_id, IB_CM_REJ_CONSUMER_DEFINED, NULL, 0,
2089 			     (void *)rej, sizeof(*rej));
2090 
2091 out:
2092 	kfree(rep_param);
2093 	kfree(rsp);
2094 	kfree(rej);
2095 
2096 	return ret;
2097 }
2098 
2099 static void srpt_cm_rej_recv(struct srpt_rdma_ch *ch,
2100 			     enum ib_cm_rej_reason reason,
2101 			     const u8 *private_data,
2102 			     u8 private_data_len)
2103 {
2104 	char *priv = NULL;
2105 	int i;
2106 
2107 	if (private_data_len && (priv = kmalloc(private_data_len * 3 + 1,
2108 						GFP_KERNEL))) {
2109 		for (i = 0; i < private_data_len; i++)
2110 			sprintf(priv + 3 * i, " %02x", private_data[i]);
2111 	}
2112 	pr_info("Received CM REJ for ch %s-%d; reason %d%s%s.\n",
2113 		ch->sess_name, ch->qp->qp_num, reason, private_data_len ?
2114 		"; private data" : "", priv ? priv : " (?)");
2115 	kfree(priv);
2116 }
2117 
2118 /**
2119  * srpt_cm_rtu_recv() - Process an IB_CM_RTU_RECEIVED or USER_ESTABLISHED event.
2120  *
2121  * An IB_CM_RTU_RECEIVED message indicates that the connection is established
2122  * and that the recipient may begin transmitting (RTU = ready to use).
2123  */
2124 static void srpt_cm_rtu_recv(struct srpt_rdma_ch *ch)
2125 {
2126 	int ret;
2127 
2128 	if (srpt_set_ch_state(ch, CH_LIVE)) {
2129 		ret = srpt_ch_qp_rts(ch, ch->qp);
2130 
2131 		if (ret == 0) {
2132 			/* Trigger wait list processing. */
2133 			ret = srpt_zerolength_write(ch);
2134 			WARN_ONCE(ret < 0, "%d\n", ret);
2135 		} else {
2136 			srpt_close_ch(ch);
2137 		}
2138 	}
2139 }
2140 
2141 /**
2142  * srpt_cm_handler() - IB connection manager callback function.
2143  *
2144  * A non-zero return value will cause the caller destroy the CM ID.
2145  *
2146  * Note: srpt_cm_handler() must only return a non-zero value when transferring
2147  * ownership of the cm_id to a channel by srpt_cm_req_recv() failed. Returning
2148  * a non-zero value in any other case will trigger a race with the
2149  * ib_destroy_cm_id() call in srpt_release_channel().
2150  */
2151 static int srpt_cm_handler(struct ib_cm_id *cm_id, struct ib_cm_event *event)
2152 {
2153 	struct srpt_rdma_ch *ch = cm_id->context;
2154 	int ret;
2155 
2156 	ret = 0;
2157 	switch (event->event) {
2158 	case IB_CM_REQ_RECEIVED:
2159 		ret = srpt_cm_req_recv(cm_id, &event->param.req_rcvd,
2160 				       event->private_data);
2161 		break;
2162 	case IB_CM_REJ_RECEIVED:
2163 		srpt_cm_rej_recv(ch, event->param.rej_rcvd.reason,
2164 				 event->private_data,
2165 				 IB_CM_REJ_PRIVATE_DATA_SIZE);
2166 		break;
2167 	case IB_CM_RTU_RECEIVED:
2168 	case IB_CM_USER_ESTABLISHED:
2169 		srpt_cm_rtu_recv(ch);
2170 		break;
2171 	case IB_CM_DREQ_RECEIVED:
2172 		srpt_disconnect_ch(ch);
2173 		break;
2174 	case IB_CM_DREP_RECEIVED:
2175 		pr_info("Received CM DREP message for ch %s-%d.\n",
2176 			ch->sess_name, ch->qp->qp_num);
2177 		srpt_close_ch(ch);
2178 		break;
2179 	case IB_CM_TIMEWAIT_EXIT:
2180 		pr_info("Received CM TimeWait exit for ch %s-%d.\n",
2181 			ch->sess_name, ch->qp->qp_num);
2182 		srpt_close_ch(ch);
2183 		break;
2184 	case IB_CM_REP_ERROR:
2185 		pr_info("Received CM REP error for ch %s-%d.\n", ch->sess_name,
2186 			ch->qp->qp_num);
2187 		break;
2188 	case IB_CM_DREQ_ERROR:
2189 		pr_info("Received CM DREQ ERROR event.\n");
2190 		break;
2191 	case IB_CM_MRA_RECEIVED:
2192 		pr_info("Received CM MRA event\n");
2193 		break;
2194 	default:
2195 		pr_err("received unrecognized CM event %d\n", event->event);
2196 		break;
2197 	}
2198 
2199 	return ret;
2200 }
2201 
2202 static int srpt_write_pending_status(struct se_cmd *se_cmd)
2203 {
2204 	struct srpt_send_ioctx *ioctx;
2205 
2206 	ioctx = container_of(se_cmd, struct srpt_send_ioctx, cmd);
2207 	return srpt_get_cmd_state(ioctx) == SRPT_STATE_NEED_DATA;
2208 }
2209 
2210 /*
2211  * srpt_write_pending() - Start data transfer from initiator to target (write).
2212  */
2213 static int srpt_write_pending(struct se_cmd *se_cmd)
2214 {
2215 	struct srpt_send_ioctx *ioctx =
2216 		container_of(se_cmd, struct srpt_send_ioctx, cmd);
2217 	struct srpt_rdma_ch *ch = ioctx->ch;
2218 	struct ib_send_wr *first_wr = NULL, *bad_wr;
2219 	struct ib_cqe *cqe = &ioctx->rdma_cqe;
2220 	enum srpt_command_state new_state;
2221 	int ret, i;
2222 
2223 	new_state = srpt_set_cmd_state(ioctx, SRPT_STATE_NEED_DATA);
2224 	WARN_ON(new_state == SRPT_STATE_DONE);
2225 
2226 	if (atomic_sub_return(ioctx->n_rdma, &ch->sq_wr_avail) < 0) {
2227 		pr_warn("%s: IB send queue full (needed %d)\n",
2228 				__func__, ioctx->n_rdma);
2229 		ret = -ENOMEM;
2230 		goto out_undo;
2231 	}
2232 
2233 	cqe->done = srpt_rdma_read_done;
2234 	for (i = ioctx->n_rw_ctx - 1; i >= 0; i--) {
2235 		struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
2236 
2237 		first_wr = rdma_rw_ctx_wrs(&ctx->rw, ch->qp, ch->sport->port,
2238 				cqe, first_wr);
2239 		cqe = NULL;
2240 	}
2241 
2242 	ret = ib_post_send(ch->qp, first_wr, &bad_wr);
2243 	if (ret) {
2244 		pr_err("%s: ib_post_send() returned %d for %d (avail: %d)\n",
2245 			 __func__, ret, ioctx->n_rdma,
2246 			 atomic_read(&ch->sq_wr_avail));
2247 		goto out_undo;
2248 	}
2249 
2250 	return 0;
2251 out_undo:
2252 	atomic_add(ioctx->n_rdma, &ch->sq_wr_avail);
2253 	return ret;
2254 }
2255 
2256 static u8 tcm_to_srp_tsk_mgmt_status(const int tcm_mgmt_status)
2257 {
2258 	switch (tcm_mgmt_status) {
2259 	case TMR_FUNCTION_COMPLETE:
2260 		return SRP_TSK_MGMT_SUCCESS;
2261 	case TMR_FUNCTION_REJECTED:
2262 		return SRP_TSK_MGMT_FUNC_NOT_SUPP;
2263 	}
2264 	return SRP_TSK_MGMT_FAILED;
2265 }
2266 
2267 /**
2268  * srpt_queue_response() - Transmits the response to a SCSI command.
2269  *
2270  * Callback function called by the TCM core. Must not block since it can be
2271  * invoked on the context of the IB completion handler.
2272  */
2273 static void srpt_queue_response(struct se_cmd *cmd)
2274 {
2275 	struct srpt_send_ioctx *ioctx =
2276 		container_of(cmd, struct srpt_send_ioctx, cmd);
2277 	struct srpt_rdma_ch *ch = ioctx->ch;
2278 	struct srpt_device *sdev = ch->sport->sdev;
2279 	struct ib_send_wr send_wr, *first_wr = &send_wr, *bad_wr;
2280 	struct ib_sge sge;
2281 	enum srpt_command_state state;
2282 	unsigned long flags;
2283 	int resp_len, ret, i;
2284 	u8 srp_tm_status;
2285 
2286 	BUG_ON(!ch);
2287 
2288 	spin_lock_irqsave(&ioctx->spinlock, flags);
2289 	state = ioctx->state;
2290 	switch (state) {
2291 	case SRPT_STATE_NEW:
2292 	case SRPT_STATE_DATA_IN:
2293 		ioctx->state = SRPT_STATE_CMD_RSP_SENT;
2294 		break;
2295 	case SRPT_STATE_MGMT:
2296 		ioctx->state = SRPT_STATE_MGMT_RSP_SENT;
2297 		break;
2298 	default:
2299 		WARN(true, "ch %p; cmd %d: unexpected command state %d\n",
2300 			ch, ioctx->ioctx.index, ioctx->state);
2301 		break;
2302 	}
2303 	spin_unlock_irqrestore(&ioctx->spinlock, flags);
2304 
2305 	if (unlikely(WARN_ON_ONCE(state == SRPT_STATE_CMD_RSP_SENT)))
2306 		return;
2307 
2308 	/* For read commands, transfer the data to the initiator. */
2309 	if (ioctx->cmd.data_direction == DMA_FROM_DEVICE &&
2310 	    ioctx->cmd.data_length &&
2311 	    !ioctx->queue_status_only) {
2312 		for (i = ioctx->n_rw_ctx - 1; i >= 0; i--) {
2313 			struct srpt_rw_ctx *ctx = &ioctx->rw_ctxs[i];
2314 
2315 			first_wr = rdma_rw_ctx_wrs(&ctx->rw, ch->qp,
2316 					ch->sport->port, NULL, first_wr);
2317 		}
2318 	}
2319 
2320 	if (state != SRPT_STATE_MGMT)
2321 		resp_len = srpt_build_cmd_rsp(ch, ioctx, ioctx->cmd.tag,
2322 					      cmd->scsi_status);
2323 	else {
2324 		srp_tm_status
2325 			= tcm_to_srp_tsk_mgmt_status(cmd->se_tmr_req->response);
2326 		resp_len = srpt_build_tskmgmt_rsp(ch, ioctx, srp_tm_status,
2327 						 ioctx->cmd.tag);
2328 	}
2329 
2330 	atomic_inc(&ch->req_lim);
2331 
2332 	if (unlikely(atomic_sub_return(1 + ioctx->n_rdma,
2333 			&ch->sq_wr_avail) < 0)) {
2334 		pr_warn("%s: IB send queue full (needed %d)\n",
2335 				__func__, ioctx->n_rdma);
2336 		ret = -ENOMEM;
2337 		goto out;
2338 	}
2339 
2340 	ib_dma_sync_single_for_device(sdev->device, ioctx->ioctx.dma, resp_len,
2341 				      DMA_TO_DEVICE);
2342 
2343 	sge.addr = ioctx->ioctx.dma;
2344 	sge.length = resp_len;
2345 	sge.lkey = sdev->pd->local_dma_lkey;
2346 
2347 	ioctx->ioctx.cqe.done = srpt_send_done;
2348 	send_wr.next = NULL;
2349 	send_wr.wr_cqe = &ioctx->ioctx.cqe;
2350 	send_wr.sg_list = &sge;
2351 	send_wr.num_sge = 1;
2352 	send_wr.opcode = IB_WR_SEND;
2353 	send_wr.send_flags = IB_SEND_SIGNALED;
2354 
2355 	ret = ib_post_send(ch->qp, first_wr, &bad_wr);
2356 	if (ret < 0) {
2357 		pr_err("%s: sending cmd response failed for tag %llu (%d)\n",
2358 			__func__, ioctx->cmd.tag, ret);
2359 		goto out;
2360 	}
2361 
2362 	return;
2363 
2364 out:
2365 	atomic_add(1 + ioctx->n_rdma, &ch->sq_wr_avail);
2366 	atomic_dec(&ch->req_lim);
2367 	srpt_set_cmd_state(ioctx, SRPT_STATE_DONE);
2368 	target_put_sess_cmd(&ioctx->cmd);
2369 }
2370 
2371 static int srpt_queue_data_in(struct se_cmd *cmd)
2372 {
2373 	srpt_queue_response(cmd);
2374 	return 0;
2375 }
2376 
2377 static void srpt_queue_tm_rsp(struct se_cmd *cmd)
2378 {
2379 	srpt_queue_response(cmd);
2380 }
2381 
2382 static void srpt_aborted_task(struct se_cmd *cmd)
2383 {
2384 }
2385 
2386 static int srpt_queue_status(struct se_cmd *cmd)
2387 {
2388 	struct srpt_send_ioctx *ioctx;
2389 
2390 	ioctx = container_of(cmd, struct srpt_send_ioctx, cmd);
2391 	BUG_ON(ioctx->sense_data != cmd->sense_buffer);
2392 	if (cmd->se_cmd_flags &
2393 	    (SCF_TRANSPORT_TASK_SENSE | SCF_EMULATED_TASK_SENSE))
2394 		WARN_ON(cmd->scsi_status != SAM_STAT_CHECK_CONDITION);
2395 	ioctx->queue_status_only = true;
2396 	srpt_queue_response(cmd);
2397 	return 0;
2398 }
2399 
2400 static void srpt_refresh_port_work(struct work_struct *work)
2401 {
2402 	struct srpt_port *sport = container_of(work, struct srpt_port, work);
2403 
2404 	srpt_refresh_port(sport);
2405 }
2406 
2407 /**
2408  * srpt_release_sdev() - Free the channel resources associated with a target.
2409  */
2410 static int srpt_release_sdev(struct srpt_device *sdev)
2411 {
2412 	int i, res;
2413 
2414 	WARN_ON_ONCE(irqs_disabled());
2415 
2416 	BUG_ON(!sdev);
2417 
2418 	mutex_lock(&sdev->mutex);
2419 	for (i = 0; i < ARRAY_SIZE(sdev->port); i++)
2420 		sdev->port[i].enabled = false;
2421 	__srpt_close_all_ch(sdev);
2422 	mutex_unlock(&sdev->mutex);
2423 
2424 	res = wait_event_interruptible(sdev->ch_releaseQ,
2425 				       list_empty_careful(&sdev->rch_list));
2426 	if (res)
2427 		pr_err("%s: interrupted.\n", __func__);
2428 
2429 	return 0;
2430 }
2431 
2432 static struct se_wwn *__srpt_lookup_wwn(const char *name)
2433 {
2434 	struct ib_device *dev;
2435 	struct srpt_device *sdev;
2436 	struct srpt_port *sport;
2437 	int i;
2438 
2439 	list_for_each_entry(sdev, &srpt_dev_list, list) {
2440 		dev = sdev->device;
2441 		if (!dev)
2442 			continue;
2443 
2444 		for (i = 0; i < dev->phys_port_cnt; i++) {
2445 			sport = &sdev->port[i];
2446 
2447 			if (strcmp(sport->port_guid, name) == 0)
2448 				return &sport->port_guid_wwn;
2449 			if (strcmp(sport->port_gid, name) == 0)
2450 				return &sport->port_gid_wwn;
2451 		}
2452 	}
2453 
2454 	return NULL;
2455 }
2456 
2457 static struct se_wwn *srpt_lookup_wwn(const char *name)
2458 {
2459 	struct se_wwn *wwn;
2460 
2461 	spin_lock(&srpt_dev_lock);
2462 	wwn = __srpt_lookup_wwn(name);
2463 	spin_unlock(&srpt_dev_lock);
2464 
2465 	return wwn;
2466 }
2467 
2468 /**
2469  * srpt_add_one() - Infiniband device addition callback function.
2470  */
2471 static void srpt_add_one(struct ib_device *device)
2472 {
2473 	struct srpt_device *sdev;
2474 	struct srpt_port *sport;
2475 	struct ib_srq_init_attr srq_attr;
2476 	int i;
2477 
2478 	pr_debug("device = %p\n", device);
2479 
2480 	sdev = kzalloc(sizeof(*sdev), GFP_KERNEL);
2481 	if (!sdev)
2482 		goto err;
2483 
2484 	sdev->device = device;
2485 	INIT_LIST_HEAD(&sdev->rch_list);
2486 	init_waitqueue_head(&sdev->ch_releaseQ);
2487 	mutex_init(&sdev->mutex);
2488 
2489 	sdev->pd = ib_alloc_pd(device, 0);
2490 	if (IS_ERR(sdev->pd))
2491 		goto free_dev;
2492 
2493 	sdev->srq_size = min(srpt_srq_size, sdev->device->attrs.max_srq_wr);
2494 
2495 	srq_attr.event_handler = srpt_srq_event;
2496 	srq_attr.srq_context = (void *)sdev;
2497 	srq_attr.attr.max_wr = sdev->srq_size;
2498 	srq_attr.attr.max_sge = 1;
2499 	srq_attr.attr.srq_limit = 0;
2500 	srq_attr.srq_type = IB_SRQT_BASIC;
2501 
2502 	sdev->srq = ib_create_srq(sdev->pd, &srq_attr);
2503 	if (IS_ERR(sdev->srq))
2504 		goto err_pd;
2505 
2506 	pr_debug("%s: create SRQ #wr= %d max_allow=%d dev= %s\n",
2507 		 __func__, sdev->srq_size, sdev->device->attrs.max_srq_wr,
2508 		 device->name);
2509 
2510 	if (!srpt_service_guid)
2511 		srpt_service_guid = be64_to_cpu(device->node_guid);
2512 
2513 	sdev->cm_id = ib_create_cm_id(device, srpt_cm_handler, sdev);
2514 	if (IS_ERR(sdev->cm_id))
2515 		goto err_srq;
2516 
2517 	/* print out target login information */
2518 	pr_debug("Target login info: id_ext=%016llx,ioc_guid=%016llx,"
2519 		 "pkey=ffff,service_id=%016llx\n", srpt_service_guid,
2520 		 srpt_service_guid, srpt_service_guid);
2521 
2522 	/*
2523 	 * We do not have a consistent service_id (ie. also id_ext of target_id)
2524 	 * to identify this target. We currently use the guid of the first HCA
2525 	 * in the system as service_id; therefore, the target_id will change
2526 	 * if this HCA is gone bad and replaced by different HCA
2527 	 */
2528 	if (ib_cm_listen(sdev->cm_id, cpu_to_be64(srpt_service_guid), 0))
2529 		goto err_cm;
2530 
2531 	INIT_IB_EVENT_HANDLER(&sdev->event_handler, sdev->device,
2532 			      srpt_event_handler);
2533 	ib_register_event_handler(&sdev->event_handler);
2534 
2535 	sdev->ioctx_ring = (struct srpt_recv_ioctx **)
2536 		srpt_alloc_ioctx_ring(sdev, sdev->srq_size,
2537 				      sizeof(*sdev->ioctx_ring[0]),
2538 				      srp_max_req_size, DMA_FROM_DEVICE);
2539 	if (!sdev->ioctx_ring)
2540 		goto err_event;
2541 
2542 	for (i = 0; i < sdev->srq_size; ++i)
2543 		srpt_post_recv(sdev, sdev->ioctx_ring[i]);
2544 
2545 	WARN_ON(sdev->device->phys_port_cnt > ARRAY_SIZE(sdev->port));
2546 
2547 	for (i = 1; i <= sdev->device->phys_port_cnt; i++) {
2548 		sport = &sdev->port[i - 1];
2549 		sport->sdev = sdev;
2550 		sport->port = i;
2551 		sport->port_attrib.srp_max_rdma_size = DEFAULT_MAX_RDMA_SIZE;
2552 		sport->port_attrib.srp_max_rsp_size = DEFAULT_MAX_RSP_SIZE;
2553 		sport->port_attrib.srp_sq_size = DEF_SRPT_SQ_SIZE;
2554 		INIT_WORK(&sport->work, srpt_refresh_port_work);
2555 
2556 		if (srpt_refresh_port(sport)) {
2557 			pr_err("MAD registration failed for %s-%d.\n",
2558 			       sdev->device->name, i);
2559 			goto err_ring;
2560 		}
2561 	}
2562 
2563 	spin_lock(&srpt_dev_lock);
2564 	list_add_tail(&sdev->list, &srpt_dev_list);
2565 	spin_unlock(&srpt_dev_lock);
2566 
2567 out:
2568 	ib_set_client_data(device, &srpt_client, sdev);
2569 	pr_debug("added %s.\n", device->name);
2570 	return;
2571 
2572 err_ring:
2573 	srpt_free_ioctx_ring((struct srpt_ioctx **)sdev->ioctx_ring, sdev,
2574 			     sdev->srq_size, srp_max_req_size,
2575 			     DMA_FROM_DEVICE);
2576 err_event:
2577 	ib_unregister_event_handler(&sdev->event_handler);
2578 err_cm:
2579 	ib_destroy_cm_id(sdev->cm_id);
2580 err_srq:
2581 	ib_destroy_srq(sdev->srq);
2582 err_pd:
2583 	ib_dealloc_pd(sdev->pd);
2584 free_dev:
2585 	kfree(sdev);
2586 err:
2587 	sdev = NULL;
2588 	pr_info("%s(%s) failed.\n", __func__, device->name);
2589 	goto out;
2590 }
2591 
2592 /**
2593  * srpt_remove_one() - InfiniBand device removal callback function.
2594  */
2595 static void srpt_remove_one(struct ib_device *device, void *client_data)
2596 {
2597 	struct srpt_device *sdev = client_data;
2598 	int i;
2599 
2600 	if (!sdev) {
2601 		pr_info("%s(%s): nothing to do.\n", __func__, device->name);
2602 		return;
2603 	}
2604 
2605 	srpt_unregister_mad_agent(sdev);
2606 
2607 	ib_unregister_event_handler(&sdev->event_handler);
2608 
2609 	/* Cancel any work queued by the just unregistered IB event handler. */
2610 	for (i = 0; i < sdev->device->phys_port_cnt; i++)
2611 		cancel_work_sync(&sdev->port[i].work);
2612 
2613 	ib_destroy_cm_id(sdev->cm_id);
2614 
2615 	/*
2616 	 * Unregistering a target must happen after destroying sdev->cm_id
2617 	 * such that no new SRP_LOGIN_REQ information units can arrive while
2618 	 * destroying the target.
2619 	 */
2620 	spin_lock(&srpt_dev_lock);
2621 	list_del(&sdev->list);
2622 	spin_unlock(&srpt_dev_lock);
2623 	srpt_release_sdev(sdev);
2624 
2625 	ib_destroy_srq(sdev->srq);
2626 	ib_dealloc_pd(sdev->pd);
2627 
2628 	srpt_free_ioctx_ring((struct srpt_ioctx **)sdev->ioctx_ring, sdev,
2629 			     sdev->srq_size, srp_max_req_size, DMA_FROM_DEVICE);
2630 	sdev->ioctx_ring = NULL;
2631 	kfree(sdev);
2632 }
2633 
2634 static struct ib_client srpt_client = {
2635 	.name = DRV_NAME,
2636 	.add = srpt_add_one,
2637 	.remove = srpt_remove_one
2638 };
2639 
2640 static int srpt_check_true(struct se_portal_group *se_tpg)
2641 {
2642 	return 1;
2643 }
2644 
2645 static int srpt_check_false(struct se_portal_group *se_tpg)
2646 {
2647 	return 0;
2648 }
2649 
2650 static char *srpt_get_fabric_name(void)
2651 {
2652 	return "srpt";
2653 }
2654 
2655 static struct srpt_port *srpt_tpg_to_sport(struct se_portal_group *tpg)
2656 {
2657 	return tpg->se_tpg_wwn->priv;
2658 }
2659 
2660 static char *srpt_get_fabric_wwn(struct se_portal_group *tpg)
2661 {
2662 	struct srpt_port *sport = srpt_tpg_to_sport(tpg);
2663 
2664 	WARN_ON_ONCE(tpg != &sport->port_guid_tpg &&
2665 		     tpg != &sport->port_gid_tpg);
2666 	return tpg == &sport->port_guid_tpg ? sport->port_guid :
2667 		sport->port_gid;
2668 }
2669 
2670 static u16 srpt_get_tag(struct se_portal_group *tpg)
2671 {
2672 	return 1;
2673 }
2674 
2675 static u32 srpt_tpg_get_inst_index(struct se_portal_group *se_tpg)
2676 {
2677 	return 1;
2678 }
2679 
2680 static void srpt_release_cmd(struct se_cmd *se_cmd)
2681 {
2682 	struct srpt_send_ioctx *ioctx = container_of(se_cmd,
2683 				struct srpt_send_ioctx, cmd);
2684 	struct srpt_rdma_ch *ch = ioctx->ch;
2685 	unsigned long flags;
2686 
2687 	WARN_ON_ONCE(ioctx->state != SRPT_STATE_DONE &&
2688 		     !(ioctx->cmd.transport_state & CMD_T_ABORTED));
2689 
2690 	if (ioctx->n_rw_ctx) {
2691 		srpt_free_rw_ctxs(ch, ioctx);
2692 		ioctx->n_rw_ctx = 0;
2693 	}
2694 
2695 	spin_lock_irqsave(&ch->spinlock, flags);
2696 	list_add(&ioctx->free_list, &ch->free_list);
2697 	spin_unlock_irqrestore(&ch->spinlock, flags);
2698 }
2699 
2700 /**
2701  * srpt_close_session() - Forcibly close a session.
2702  *
2703  * Callback function invoked by the TCM core to clean up sessions associated
2704  * with a node ACL when the user invokes
2705  * rmdir /sys/kernel/config/target/$driver/$port/$tpg/acls/$i_port_id
2706  */
2707 static void srpt_close_session(struct se_session *se_sess)
2708 {
2709 	DECLARE_COMPLETION_ONSTACK(release_done);
2710 	struct srpt_rdma_ch *ch = se_sess->fabric_sess_ptr;
2711 	struct srpt_device *sdev = ch->sport->sdev;
2712 	bool wait;
2713 
2714 	pr_debug("ch %s-%d state %d\n", ch->sess_name, ch->qp->qp_num,
2715 		 ch->state);
2716 
2717 	mutex_lock(&sdev->mutex);
2718 	BUG_ON(ch->release_done);
2719 	ch->release_done = &release_done;
2720 	wait = !list_empty(&ch->list);
2721 	srpt_disconnect_ch(ch);
2722 	mutex_unlock(&sdev->mutex);
2723 
2724 	if (!wait)
2725 		return;
2726 
2727 	while (wait_for_completion_timeout(&release_done, 180 * HZ) == 0)
2728 		pr_info("%s(%s-%d state %d): still waiting ...\n", __func__,
2729 			ch->sess_name, ch->qp->qp_num, ch->state);
2730 }
2731 
2732 /**
2733  * srpt_sess_get_index() - Return the value of scsiAttIntrPortIndex (SCSI-MIB).
2734  *
2735  * A quote from RFC 4455 (SCSI-MIB) about this MIB object:
2736  * This object represents an arbitrary integer used to uniquely identify a
2737  * particular attached remote initiator port to a particular SCSI target port
2738  * within a particular SCSI target device within a particular SCSI instance.
2739  */
2740 static u32 srpt_sess_get_index(struct se_session *se_sess)
2741 {
2742 	return 0;
2743 }
2744 
2745 static void srpt_set_default_node_attrs(struct se_node_acl *nacl)
2746 {
2747 }
2748 
2749 /* Note: only used from inside debug printk's by the TCM core. */
2750 static int srpt_get_tcm_cmd_state(struct se_cmd *se_cmd)
2751 {
2752 	struct srpt_send_ioctx *ioctx;
2753 
2754 	ioctx = container_of(se_cmd, struct srpt_send_ioctx, cmd);
2755 	return srpt_get_cmd_state(ioctx);
2756 }
2757 
2758 static int srpt_parse_guid(u64 *guid, const char *name)
2759 {
2760 	u16 w[4];
2761 	int ret = -EINVAL;
2762 
2763 	if (sscanf(name, "%hx:%hx:%hx:%hx", &w[0], &w[1], &w[2], &w[3]) != 4)
2764 		goto out;
2765 	*guid = get_unaligned_be64(w);
2766 	ret = 0;
2767 out:
2768 	return ret;
2769 }
2770 
2771 /**
2772  * srpt_parse_i_port_id() - Parse an initiator port ID.
2773  * @name: ASCII representation of a 128-bit initiator port ID.
2774  * @i_port_id: Binary 128-bit port ID.
2775  */
2776 static int srpt_parse_i_port_id(u8 i_port_id[16], const char *name)
2777 {
2778 	const char *p;
2779 	unsigned len, count, leading_zero_bytes;
2780 	int ret, rc;
2781 
2782 	p = name;
2783 	if (strncasecmp(p, "0x", 2) == 0)
2784 		p += 2;
2785 	ret = -EINVAL;
2786 	len = strlen(p);
2787 	if (len % 2)
2788 		goto out;
2789 	count = min(len / 2, 16U);
2790 	leading_zero_bytes = 16 - count;
2791 	memset(i_port_id, 0, leading_zero_bytes);
2792 	rc = hex2bin(i_port_id + leading_zero_bytes, p, count);
2793 	if (rc < 0)
2794 		pr_debug("hex2bin failed for srpt_parse_i_port_id: %d\n", rc);
2795 	ret = 0;
2796 out:
2797 	return ret;
2798 }
2799 
2800 /*
2801  * configfs callback function invoked for
2802  * mkdir /sys/kernel/config/target/$driver/$port/$tpg/acls/$i_port_id
2803  */
2804 static int srpt_init_nodeacl(struct se_node_acl *se_nacl, const char *name)
2805 {
2806 	u64 guid;
2807 	u8 i_port_id[16];
2808 	int ret;
2809 
2810 	ret = srpt_parse_guid(&guid, name);
2811 	if (ret < 0)
2812 		ret = srpt_parse_i_port_id(i_port_id, name);
2813 	if (ret < 0)
2814 		pr_err("invalid initiator port ID %s\n", name);
2815 	return ret;
2816 }
2817 
2818 static ssize_t srpt_tpg_attrib_srp_max_rdma_size_show(struct config_item *item,
2819 		char *page)
2820 {
2821 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
2822 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
2823 
2824 	return sprintf(page, "%u\n", sport->port_attrib.srp_max_rdma_size);
2825 }
2826 
2827 static ssize_t srpt_tpg_attrib_srp_max_rdma_size_store(struct config_item *item,
2828 		const char *page, size_t count)
2829 {
2830 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
2831 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
2832 	unsigned long val;
2833 	int ret;
2834 
2835 	ret = kstrtoul(page, 0, &val);
2836 	if (ret < 0) {
2837 		pr_err("kstrtoul() failed with ret: %d\n", ret);
2838 		return -EINVAL;
2839 	}
2840 	if (val > MAX_SRPT_RDMA_SIZE) {
2841 		pr_err("val: %lu exceeds MAX_SRPT_RDMA_SIZE: %d\n", val,
2842 			MAX_SRPT_RDMA_SIZE);
2843 		return -EINVAL;
2844 	}
2845 	if (val < DEFAULT_MAX_RDMA_SIZE) {
2846 		pr_err("val: %lu smaller than DEFAULT_MAX_RDMA_SIZE: %d\n",
2847 			val, DEFAULT_MAX_RDMA_SIZE);
2848 		return -EINVAL;
2849 	}
2850 	sport->port_attrib.srp_max_rdma_size = val;
2851 
2852 	return count;
2853 }
2854 
2855 static ssize_t srpt_tpg_attrib_srp_max_rsp_size_show(struct config_item *item,
2856 		char *page)
2857 {
2858 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
2859 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
2860 
2861 	return sprintf(page, "%u\n", sport->port_attrib.srp_max_rsp_size);
2862 }
2863 
2864 static ssize_t srpt_tpg_attrib_srp_max_rsp_size_store(struct config_item *item,
2865 		const char *page, size_t count)
2866 {
2867 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
2868 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
2869 	unsigned long val;
2870 	int ret;
2871 
2872 	ret = kstrtoul(page, 0, &val);
2873 	if (ret < 0) {
2874 		pr_err("kstrtoul() failed with ret: %d\n", ret);
2875 		return -EINVAL;
2876 	}
2877 	if (val > MAX_SRPT_RSP_SIZE) {
2878 		pr_err("val: %lu exceeds MAX_SRPT_RSP_SIZE: %d\n", val,
2879 			MAX_SRPT_RSP_SIZE);
2880 		return -EINVAL;
2881 	}
2882 	if (val < MIN_MAX_RSP_SIZE) {
2883 		pr_err("val: %lu smaller than MIN_MAX_RSP_SIZE: %d\n", val,
2884 			MIN_MAX_RSP_SIZE);
2885 		return -EINVAL;
2886 	}
2887 	sport->port_attrib.srp_max_rsp_size = val;
2888 
2889 	return count;
2890 }
2891 
2892 static ssize_t srpt_tpg_attrib_srp_sq_size_show(struct config_item *item,
2893 		char *page)
2894 {
2895 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
2896 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
2897 
2898 	return sprintf(page, "%u\n", sport->port_attrib.srp_sq_size);
2899 }
2900 
2901 static ssize_t srpt_tpg_attrib_srp_sq_size_store(struct config_item *item,
2902 		const char *page, size_t count)
2903 {
2904 	struct se_portal_group *se_tpg = attrib_to_tpg(item);
2905 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
2906 	unsigned long val;
2907 	int ret;
2908 
2909 	ret = kstrtoul(page, 0, &val);
2910 	if (ret < 0) {
2911 		pr_err("kstrtoul() failed with ret: %d\n", ret);
2912 		return -EINVAL;
2913 	}
2914 	if (val > MAX_SRPT_SRQ_SIZE) {
2915 		pr_err("val: %lu exceeds MAX_SRPT_SRQ_SIZE: %d\n", val,
2916 			MAX_SRPT_SRQ_SIZE);
2917 		return -EINVAL;
2918 	}
2919 	if (val < MIN_SRPT_SRQ_SIZE) {
2920 		pr_err("val: %lu smaller than MIN_SRPT_SRQ_SIZE: %d\n", val,
2921 			MIN_SRPT_SRQ_SIZE);
2922 		return -EINVAL;
2923 	}
2924 	sport->port_attrib.srp_sq_size = val;
2925 
2926 	return count;
2927 }
2928 
2929 CONFIGFS_ATTR(srpt_tpg_attrib_,  srp_max_rdma_size);
2930 CONFIGFS_ATTR(srpt_tpg_attrib_,  srp_max_rsp_size);
2931 CONFIGFS_ATTR(srpt_tpg_attrib_,  srp_sq_size);
2932 
2933 static struct configfs_attribute *srpt_tpg_attrib_attrs[] = {
2934 	&srpt_tpg_attrib_attr_srp_max_rdma_size,
2935 	&srpt_tpg_attrib_attr_srp_max_rsp_size,
2936 	&srpt_tpg_attrib_attr_srp_sq_size,
2937 	NULL,
2938 };
2939 
2940 static ssize_t srpt_tpg_enable_show(struct config_item *item, char *page)
2941 {
2942 	struct se_portal_group *se_tpg = to_tpg(item);
2943 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
2944 
2945 	return snprintf(page, PAGE_SIZE, "%d\n", (sport->enabled) ? 1: 0);
2946 }
2947 
2948 static ssize_t srpt_tpg_enable_store(struct config_item *item,
2949 		const char *page, size_t count)
2950 {
2951 	struct se_portal_group *se_tpg = to_tpg(item);
2952 	struct srpt_port *sport = srpt_tpg_to_sport(se_tpg);
2953 	struct srpt_device *sdev = sport->sdev;
2954 	struct srpt_rdma_ch *ch;
2955 	unsigned long tmp;
2956         int ret;
2957 
2958 	ret = kstrtoul(page, 0, &tmp);
2959 	if (ret < 0) {
2960 		pr_err("Unable to extract srpt_tpg_store_enable\n");
2961 		return -EINVAL;
2962 	}
2963 
2964 	if ((tmp != 0) && (tmp != 1)) {
2965 		pr_err("Illegal value for srpt_tpg_store_enable: %lu\n", tmp);
2966 		return -EINVAL;
2967 	}
2968 	if (sport->enabled == tmp)
2969 		goto out;
2970 	sport->enabled = tmp;
2971 	if (sport->enabled)
2972 		goto out;
2973 
2974 	mutex_lock(&sdev->mutex);
2975 	list_for_each_entry(ch, &sdev->rch_list, list) {
2976 		if (ch->sport == sport) {
2977 			pr_debug("%s: ch %p %s-%d\n", __func__, ch,
2978 				 ch->sess_name, ch->qp->qp_num);
2979 			srpt_disconnect_ch(ch);
2980 			srpt_close_ch(ch);
2981 		}
2982 	}
2983 	mutex_unlock(&sdev->mutex);
2984 
2985 out:
2986 	return count;
2987 }
2988 
2989 CONFIGFS_ATTR(srpt_tpg_, enable);
2990 
2991 static struct configfs_attribute *srpt_tpg_attrs[] = {
2992 	&srpt_tpg_attr_enable,
2993 	NULL,
2994 };
2995 
2996 /**
2997  * configfs callback invoked for
2998  * mkdir /sys/kernel/config/target/$driver/$port/$tpg
2999  */
3000 static struct se_portal_group *srpt_make_tpg(struct se_wwn *wwn,
3001 					     struct config_group *group,
3002 					     const char *name)
3003 {
3004 	struct srpt_port *sport = wwn->priv;
3005 	static struct se_portal_group *tpg;
3006 	int res;
3007 
3008 	WARN_ON_ONCE(wwn != &sport->port_guid_wwn &&
3009 		     wwn != &sport->port_gid_wwn);
3010 	tpg = wwn == &sport->port_guid_wwn ? &sport->port_guid_tpg :
3011 		&sport->port_gid_tpg;
3012 	res = core_tpg_register(wwn, tpg, SCSI_PROTOCOL_SRP);
3013 	if (res)
3014 		return ERR_PTR(res);
3015 
3016 	return tpg;
3017 }
3018 
3019 /**
3020  * configfs callback invoked for
3021  * rmdir /sys/kernel/config/target/$driver/$port/$tpg
3022  */
3023 static void srpt_drop_tpg(struct se_portal_group *tpg)
3024 {
3025 	struct srpt_port *sport = srpt_tpg_to_sport(tpg);
3026 
3027 	sport->enabled = false;
3028 	core_tpg_deregister(tpg);
3029 }
3030 
3031 /**
3032  * configfs callback invoked for
3033  * mkdir /sys/kernel/config/target/$driver/$port
3034  */
3035 static struct se_wwn *srpt_make_tport(struct target_fabric_configfs *tf,
3036 				      struct config_group *group,
3037 				      const char *name)
3038 {
3039 	return srpt_lookup_wwn(name) ? : ERR_PTR(-EINVAL);
3040 }
3041 
3042 /**
3043  * configfs callback invoked for
3044  * rmdir /sys/kernel/config/target/$driver/$port
3045  */
3046 static void srpt_drop_tport(struct se_wwn *wwn)
3047 {
3048 }
3049 
3050 static ssize_t srpt_wwn_version_show(struct config_item *item, char *buf)
3051 {
3052 	return scnprintf(buf, PAGE_SIZE, "%s\n", DRV_VERSION);
3053 }
3054 
3055 CONFIGFS_ATTR_RO(srpt_wwn_, version);
3056 
3057 static struct configfs_attribute *srpt_wwn_attrs[] = {
3058 	&srpt_wwn_attr_version,
3059 	NULL,
3060 };
3061 
3062 static const struct target_core_fabric_ops srpt_template = {
3063 	.module				= THIS_MODULE,
3064 	.name				= "srpt",
3065 	.get_fabric_name		= srpt_get_fabric_name,
3066 	.tpg_get_wwn			= srpt_get_fabric_wwn,
3067 	.tpg_get_tag			= srpt_get_tag,
3068 	.tpg_check_demo_mode		= srpt_check_false,
3069 	.tpg_check_demo_mode_cache	= srpt_check_true,
3070 	.tpg_check_demo_mode_write_protect = srpt_check_true,
3071 	.tpg_check_prod_mode_write_protect = srpt_check_false,
3072 	.tpg_get_inst_index		= srpt_tpg_get_inst_index,
3073 	.release_cmd			= srpt_release_cmd,
3074 	.check_stop_free		= srpt_check_stop_free,
3075 	.close_session			= srpt_close_session,
3076 	.sess_get_index			= srpt_sess_get_index,
3077 	.sess_get_initiator_sid		= NULL,
3078 	.write_pending			= srpt_write_pending,
3079 	.write_pending_status		= srpt_write_pending_status,
3080 	.set_default_node_attributes	= srpt_set_default_node_attrs,
3081 	.get_cmd_state			= srpt_get_tcm_cmd_state,
3082 	.queue_data_in			= srpt_queue_data_in,
3083 	.queue_status			= srpt_queue_status,
3084 	.queue_tm_rsp			= srpt_queue_tm_rsp,
3085 	.aborted_task			= srpt_aborted_task,
3086 	/*
3087 	 * Setup function pointers for generic logic in
3088 	 * target_core_fabric_configfs.c
3089 	 */
3090 	.fabric_make_wwn		= srpt_make_tport,
3091 	.fabric_drop_wwn		= srpt_drop_tport,
3092 	.fabric_make_tpg		= srpt_make_tpg,
3093 	.fabric_drop_tpg		= srpt_drop_tpg,
3094 	.fabric_init_nodeacl		= srpt_init_nodeacl,
3095 
3096 	.tfc_wwn_attrs			= srpt_wwn_attrs,
3097 	.tfc_tpg_base_attrs		= srpt_tpg_attrs,
3098 	.tfc_tpg_attrib_attrs		= srpt_tpg_attrib_attrs,
3099 };
3100 
3101 /**
3102  * srpt_init_module() - Kernel module initialization.
3103  *
3104  * Note: Since ib_register_client() registers callback functions, and since at
3105  * least one of these callback functions (srpt_add_one()) calls target core
3106  * functions, this driver must be registered with the target core before
3107  * ib_register_client() is called.
3108  */
3109 static int __init srpt_init_module(void)
3110 {
3111 	int ret;
3112 
3113 	ret = -EINVAL;
3114 	if (srp_max_req_size < MIN_MAX_REQ_SIZE) {
3115 		pr_err("invalid value %d for kernel module parameter"
3116 		       " srp_max_req_size -- must be at least %d.\n",
3117 		       srp_max_req_size, MIN_MAX_REQ_SIZE);
3118 		goto out;
3119 	}
3120 
3121 	if (srpt_srq_size < MIN_SRPT_SRQ_SIZE
3122 	    || srpt_srq_size > MAX_SRPT_SRQ_SIZE) {
3123 		pr_err("invalid value %d for kernel module parameter"
3124 		       " srpt_srq_size -- must be in the range [%d..%d].\n",
3125 		       srpt_srq_size, MIN_SRPT_SRQ_SIZE, MAX_SRPT_SRQ_SIZE);
3126 		goto out;
3127 	}
3128 
3129 	ret = target_register_template(&srpt_template);
3130 	if (ret)
3131 		goto out;
3132 
3133 	ret = ib_register_client(&srpt_client);
3134 	if (ret) {
3135 		pr_err("couldn't register IB client\n");
3136 		goto out_unregister_target;
3137 	}
3138 
3139 	return 0;
3140 
3141 out_unregister_target:
3142 	target_unregister_template(&srpt_template);
3143 out:
3144 	return ret;
3145 }
3146 
3147 static void __exit srpt_cleanup_module(void)
3148 {
3149 	ib_unregister_client(&srpt_client);
3150 	target_unregister_template(&srpt_template);
3151 }
3152 
3153 module_init(srpt_init_module);
3154 module_exit(srpt_cleanup_module);
3155