xref: /linux/drivers/target/target_core_transport.c (revision b85d45947951d23cb22d90caecf4c1eb81342c96)
1 /*******************************************************************************
2  * Filename:  target_core_transport.c
3  *
4  * This file contains the Generic Target Engine Core.
5  *
6  * (c) Copyright 2002-2013 Datera, Inc.
7  *
8  * Nicholas A. Bellinger <nab@kernel.org>
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License as published by
12  * the Free Software Foundation; either version 2 of the License, or
13  * (at your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18  * GNU General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with this program; if not, write to the Free Software
22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
23  *
24  ******************************************************************************/
25 
26 #include <linux/net.h>
27 #include <linux/delay.h>
28 #include <linux/string.h>
29 #include <linux/timer.h>
30 #include <linux/slab.h>
31 #include <linux/spinlock.h>
32 #include <linux/kthread.h>
33 #include <linux/in.h>
34 #include <linux/cdrom.h>
35 #include <linux/module.h>
36 #include <linux/ratelimit.h>
37 #include <linux/vmalloc.h>
38 #include <asm/unaligned.h>
39 #include <net/sock.h>
40 #include <net/tcp.h>
41 #include <scsi/scsi_proto.h>
42 #include <scsi/scsi_common.h>
43 
44 #include <target/target_core_base.h>
45 #include <target/target_core_backend.h>
46 #include <target/target_core_fabric.h>
47 
48 #include "target_core_internal.h"
49 #include "target_core_alua.h"
50 #include "target_core_pr.h"
51 #include "target_core_ua.h"
52 
53 #define CREATE_TRACE_POINTS
54 #include <trace/events/target.h>
55 
56 static struct workqueue_struct *target_completion_wq;
57 static struct kmem_cache *se_sess_cache;
58 struct kmem_cache *se_ua_cache;
59 struct kmem_cache *t10_pr_reg_cache;
60 struct kmem_cache *t10_alua_lu_gp_cache;
61 struct kmem_cache *t10_alua_lu_gp_mem_cache;
62 struct kmem_cache *t10_alua_tg_pt_gp_cache;
63 struct kmem_cache *t10_alua_lba_map_cache;
64 struct kmem_cache *t10_alua_lba_map_mem_cache;
65 
66 static void transport_complete_task_attr(struct se_cmd *cmd);
67 static void transport_handle_queue_full(struct se_cmd *cmd,
68 		struct se_device *dev);
69 static int transport_put_cmd(struct se_cmd *cmd);
70 static void target_complete_ok_work(struct work_struct *work);
71 
72 int init_se_kmem_caches(void)
73 {
74 	se_sess_cache = kmem_cache_create("se_sess_cache",
75 			sizeof(struct se_session), __alignof__(struct se_session),
76 			0, NULL);
77 	if (!se_sess_cache) {
78 		pr_err("kmem_cache_create() for struct se_session"
79 				" failed\n");
80 		goto out;
81 	}
82 	se_ua_cache = kmem_cache_create("se_ua_cache",
83 			sizeof(struct se_ua), __alignof__(struct se_ua),
84 			0, NULL);
85 	if (!se_ua_cache) {
86 		pr_err("kmem_cache_create() for struct se_ua failed\n");
87 		goto out_free_sess_cache;
88 	}
89 	t10_pr_reg_cache = kmem_cache_create("t10_pr_reg_cache",
90 			sizeof(struct t10_pr_registration),
91 			__alignof__(struct t10_pr_registration), 0, NULL);
92 	if (!t10_pr_reg_cache) {
93 		pr_err("kmem_cache_create() for struct t10_pr_registration"
94 				" failed\n");
95 		goto out_free_ua_cache;
96 	}
97 	t10_alua_lu_gp_cache = kmem_cache_create("t10_alua_lu_gp_cache",
98 			sizeof(struct t10_alua_lu_gp), __alignof__(struct t10_alua_lu_gp),
99 			0, NULL);
100 	if (!t10_alua_lu_gp_cache) {
101 		pr_err("kmem_cache_create() for t10_alua_lu_gp_cache"
102 				" failed\n");
103 		goto out_free_pr_reg_cache;
104 	}
105 	t10_alua_lu_gp_mem_cache = kmem_cache_create("t10_alua_lu_gp_mem_cache",
106 			sizeof(struct t10_alua_lu_gp_member),
107 			__alignof__(struct t10_alua_lu_gp_member), 0, NULL);
108 	if (!t10_alua_lu_gp_mem_cache) {
109 		pr_err("kmem_cache_create() for t10_alua_lu_gp_mem_"
110 				"cache failed\n");
111 		goto out_free_lu_gp_cache;
112 	}
113 	t10_alua_tg_pt_gp_cache = kmem_cache_create("t10_alua_tg_pt_gp_cache",
114 			sizeof(struct t10_alua_tg_pt_gp),
115 			__alignof__(struct t10_alua_tg_pt_gp), 0, NULL);
116 	if (!t10_alua_tg_pt_gp_cache) {
117 		pr_err("kmem_cache_create() for t10_alua_tg_pt_gp_"
118 				"cache failed\n");
119 		goto out_free_lu_gp_mem_cache;
120 	}
121 	t10_alua_lba_map_cache = kmem_cache_create(
122 			"t10_alua_lba_map_cache",
123 			sizeof(struct t10_alua_lba_map),
124 			__alignof__(struct t10_alua_lba_map), 0, NULL);
125 	if (!t10_alua_lba_map_cache) {
126 		pr_err("kmem_cache_create() for t10_alua_lba_map_"
127 				"cache failed\n");
128 		goto out_free_tg_pt_gp_cache;
129 	}
130 	t10_alua_lba_map_mem_cache = kmem_cache_create(
131 			"t10_alua_lba_map_mem_cache",
132 			sizeof(struct t10_alua_lba_map_member),
133 			__alignof__(struct t10_alua_lba_map_member), 0, NULL);
134 	if (!t10_alua_lba_map_mem_cache) {
135 		pr_err("kmem_cache_create() for t10_alua_lba_map_mem_"
136 				"cache failed\n");
137 		goto out_free_lba_map_cache;
138 	}
139 
140 	target_completion_wq = alloc_workqueue("target_completion",
141 					       WQ_MEM_RECLAIM, 0);
142 	if (!target_completion_wq)
143 		goto out_free_lba_map_mem_cache;
144 
145 	return 0;
146 
147 out_free_lba_map_mem_cache:
148 	kmem_cache_destroy(t10_alua_lba_map_mem_cache);
149 out_free_lba_map_cache:
150 	kmem_cache_destroy(t10_alua_lba_map_cache);
151 out_free_tg_pt_gp_cache:
152 	kmem_cache_destroy(t10_alua_tg_pt_gp_cache);
153 out_free_lu_gp_mem_cache:
154 	kmem_cache_destroy(t10_alua_lu_gp_mem_cache);
155 out_free_lu_gp_cache:
156 	kmem_cache_destroy(t10_alua_lu_gp_cache);
157 out_free_pr_reg_cache:
158 	kmem_cache_destroy(t10_pr_reg_cache);
159 out_free_ua_cache:
160 	kmem_cache_destroy(se_ua_cache);
161 out_free_sess_cache:
162 	kmem_cache_destroy(se_sess_cache);
163 out:
164 	return -ENOMEM;
165 }
166 
167 void release_se_kmem_caches(void)
168 {
169 	destroy_workqueue(target_completion_wq);
170 	kmem_cache_destroy(se_sess_cache);
171 	kmem_cache_destroy(se_ua_cache);
172 	kmem_cache_destroy(t10_pr_reg_cache);
173 	kmem_cache_destroy(t10_alua_lu_gp_cache);
174 	kmem_cache_destroy(t10_alua_lu_gp_mem_cache);
175 	kmem_cache_destroy(t10_alua_tg_pt_gp_cache);
176 	kmem_cache_destroy(t10_alua_lba_map_cache);
177 	kmem_cache_destroy(t10_alua_lba_map_mem_cache);
178 }
179 
180 /* This code ensures unique mib indexes are handed out. */
181 static DEFINE_SPINLOCK(scsi_mib_index_lock);
182 static u32 scsi_mib_index[SCSI_INDEX_TYPE_MAX];
183 
184 /*
185  * Allocate a new row index for the entry type specified
186  */
187 u32 scsi_get_new_index(scsi_index_t type)
188 {
189 	u32 new_index;
190 
191 	BUG_ON((type < 0) || (type >= SCSI_INDEX_TYPE_MAX));
192 
193 	spin_lock(&scsi_mib_index_lock);
194 	new_index = ++scsi_mib_index[type];
195 	spin_unlock(&scsi_mib_index_lock);
196 
197 	return new_index;
198 }
199 
200 void transport_subsystem_check_init(void)
201 {
202 	int ret;
203 	static int sub_api_initialized;
204 
205 	if (sub_api_initialized)
206 		return;
207 
208 	ret = request_module("target_core_iblock");
209 	if (ret != 0)
210 		pr_err("Unable to load target_core_iblock\n");
211 
212 	ret = request_module("target_core_file");
213 	if (ret != 0)
214 		pr_err("Unable to load target_core_file\n");
215 
216 	ret = request_module("target_core_pscsi");
217 	if (ret != 0)
218 		pr_err("Unable to load target_core_pscsi\n");
219 
220 	ret = request_module("target_core_user");
221 	if (ret != 0)
222 		pr_err("Unable to load target_core_user\n");
223 
224 	sub_api_initialized = 1;
225 }
226 
227 struct se_session *transport_init_session(enum target_prot_op sup_prot_ops)
228 {
229 	struct se_session *se_sess;
230 
231 	se_sess = kmem_cache_zalloc(se_sess_cache, GFP_KERNEL);
232 	if (!se_sess) {
233 		pr_err("Unable to allocate struct se_session from"
234 				" se_sess_cache\n");
235 		return ERR_PTR(-ENOMEM);
236 	}
237 	INIT_LIST_HEAD(&se_sess->sess_list);
238 	INIT_LIST_HEAD(&se_sess->sess_acl_list);
239 	INIT_LIST_HEAD(&se_sess->sess_cmd_list);
240 	INIT_LIST_HEAD(&se_sess->sess_wait_list);
241 	spin_lock_init(&se_sess->sess_cmd_lock);
242 	kref_init(&se_sess->sess_kref);
243 	se_sess->sup_prot_ops = sup_prot_ops;
244 
245 	return se_sess;
246 }
247 EXPORT_SYMBOL(transport_init_session);
248 
249 int transport_alloc_session_tags(struct se_session *se_sess,
250 			         unsigned int tag_num, unsigned int tag_size)
251 {
252 	int rc;
253 
254 	se_sess->sess_cmd_map = kzalloc(tag_num * tag_size,
255 					GFP_KERNEL | __GFP_NOWARN | __GFP_REPEAT);
256 	if (!se_sess->sess_cmd_map) {
257 		se_sess->sess_cmd_map = vzalloc(tag_num * tag_size);
258 		if (!se_sess->sess_cmd_map) {
259 			pr_err("Unable to allocate se_sess->sess_cmd_map\n");
260 			return -ENOMEM;
261 		}
262 	}
263 
264 	rc = percpu_ida_init(&se_sess->sess_tag_pool, tag_num);
265 	if (rc < 0) {
266 		pr_err("Unable to init se_sess->sess_tag_pool,"
267 			" tag_num: %u\n", tag_num);
268 		kvfree(se_sess->sess_cmd_map);
269 		se_sess->sess_cmd_map = NULL;
270 		return -ENOMEM;
271 	}
272 
273 	return 0;
274 }
275 EXPORT_SYMBOL(transport_alloc_session_tags);
276 
277 struct se_session *transport_init_session_tags(unsigned int tag_num,
278 					       unsigned int tag_size,
279 					       enum target_prot_op sup_prot_ops)
280 {
281 	struct se_session *se_sess;
282 	int rc;
283 
284 	se_sess = transport_init_session(sup_prot_ops);
285 	if (IS_ERR(se_sess))
286 		return se_sess;
287 
288 	rc = transport_alloc_session_tags(se_sess, tag_num, tag_size);
289 	if (rc < 0) {
290 		transport_free_session(se_sess);
291 		return ERR_PTR(-ENOMEM);
292 	}
293 
294 	return se_sess;
295 }
296 EXPORT_SYMBOL(transport_init_session_tags);
297 
298 /*
299  * Called with spin_lock_irqsave(&struct se_portal_group->session_lock called.
300  */
301 void __transport_register_session(
302 	struct se_portal_group *se_tpg,
303 	struct se_node_acl *se_nacl,
304 	struct se_session *se_sess,
305 	void *fabric_sess_ptr)
306 {
307 	const struct target_core_fabric_ops *tfo = se_tpg->se_tpg_tfo;
308 	unsigned char buf[PR_REG_ISID_LEN];
309 
310 	se_sess->se_tpg = se_tpg;
311 	se_sess->fabric_sess_ptr = fabric_sess_ptr;
312 	/*
313 	 * Used by struct se_node_acl's under ConfigFS to locate active se_session-t
314 	 *
315 	 * Only set for struct se_session's that will actually be moving I/O.
316 	 * eg: *NOT* discovery sessions.
317 	 */
318 	if (se_nacl) {
319 		/*
320 		 *
321 		 * Determine if fabric allows for T10-PI feature bits exposed to
322 		 * initiators for device backends with !dev->dev_attrib.pi_prot_type.
323 		 *
324 		 * If so, then always save prot_type on a per se_node_acl node
325 		 * basis and re-instate the previous sess_prot_type to avoid
326 		 * disabling PI from below any previously initiator side
327 		 * registered LUNs.
328 		 */
329 		if (se_nacl->saved_prot_type)
330 			se_sess->sess_prot_type = se_nacl->saved_prot_type;
331 		else if (tfo->tpg_check_prot_fabric_only)
332 			se_sess->sess_prot_type = se_nacl->saved_prot_type =
333 					tfo->tpg_check_prot_fabric_only(se_tpg);
334 		/*
335 		 * If the fabric module supports an ISID based TransportID,
336 		 * save this value in binary from the fabric I_T Nexus now.
337 		 */
338 		if (se_tpg->se_tpg_tfo->sess_get_initiator_sid != NULL) {
339 			memset(&buf[0], 0, PR_REG_ISID_LEN);
340 			se_tpg->se_tpg_tfo->sess_get_initiator_sid(se_sess,
341 					&buf[0], PR_REG_ISID_LEN);
342 			se_sess->sess_bin_isid = get_unaligned_be64(&buf[0]);
343 		}
344 		kref_get(&se_nacl->acl_kref);
345 
346 		spin_lock_irq(&se_nacl->nacl_sess_lock);
347 		/*
348 		 * The se_nacl->nacl_sess pointer will be set to the
349 		 * last active I_T Nexus for each struct se_node_acl.
350 		 */
351 		se_nacl->nacl_sess = se_sess;
352 
353 		list_add_tail(&se_sess->sess_acl_list,
354 			      &se_nacl->acl_sess_list);
355 		spin_unlock_irq(&se_nacl->nacl_sess_lock);
356 	}
357 	list_add_tail(&se_sess->sess_list, &se_tpg->tpg_sess_list);
358 
359 	pr_debug("TARGET_CORE[%s]: Registered fabric_sess_ptr: %p\n",
360 		se_tpg->se_tpg_tfo->get_fabric_name(), se_sess->fabric_sess_ptr);
361 }
362 EXPORT_SYMBOL(__transport_register_session);
363 
364 void transport_register_session(
365 	struct se_portal_group *se_tpg,
366 	struct se_node_acl *se_nacl,
367 	struct se_session *se_sess,
368 	void *fabric_sess_ptr)
369 {
370 	unsigned long flags;
371 
372 	spin_lock_irqsave(&se_tpg->session_lock, flags);
373 	__transport_register_session(se_tpg, se_nacl, se_sess, fabric_sess_ptr);
374 	spin_unlock_irqrestore(&se_tpg->session_lock, flags);
375 }
376 EXPORT_SYMBOL(transport_register_session);
377 
378 static void target_release_session(struct kref *kref)
379 {
380 	struct se_session *se_sess = container_of(kref,
381 			struct se_session, sess_kref);
382 	struct se_portal_group *se_tpg = se_sess->se_tpg;
383 
384 	se_tpg->se_tpg_tfo->close_session(se_sess);
385 }
386 
387 void target_get_session(struct se_session *se_sess)
388 {
389 	kref_get(&se_sess->sess_kref);
390 }
391 EXPORT_SYMBOL(target_get_session);
392 
393 void target_put_session(struct se_session *se_sess)
394 {
395 	kref_put(&se_sess->sess_kref, target_release_session);
396 }
397 EXPORT_SYMBOL(target_put_session);
398 
399 ssize_t target_show_dynamic_sessions(struct se_portal_group *se_tpg, char *page)
400 {
401 	struct se_session *se_sess;
402 	ssize_t len = 0;
403 
404 	spin_lock_bh(&se_tpg->session_lock);
405 	list_for_each_entry(se_sess, &se_tpg->tpg_sess_list, sess_list) {
406 		if (!se_sess->se_node_acl)
407 			continue;
408 		if (!se_sess->se_node_acl->dynamic_node_acl)
409 			continue;
410 		if (strlen(se_sess->se_node_acl->initiatorname) + 1 + len > PAGE_SIZE)
411 			break;
412 
413 		len += snprintf(page + len, PAGE_SIZE - len, "%s\n",
414 				se_sess->se_node_acl->initiatorname);
415 		len += 1; /* Include NULL terminator */
416 	}
417 	spin_unlock_bh(&se_tpg->session_lock);
418 
419 	return len;
420 }
421 EXPORT_SYMBOL(target_show_dynamic_sessions);
422 
423 static void target_complete_nacl(struct kref *kref)
424 {
425 	struct se_node_acl *nacl = container_of(kref,
426 				struct se_node_acl, acl_kref);
427 
428 	complete(&nacl->acl_free_comp);
429 }
430 
431 void target_put_nacl(struct se_node_acl *nacl)
432 {
433 	kref_put(&nacl->acl_kref, target_complete_nacl);
434 }
435 
436 void transport_deregister_session_configfs(struct se_session *se_sess)
437 {
438 	struct se_node_acl *se_nacl;
439 	unsigned long flags;
440 	/*
441 	 * Used by struct se_node_acl's under ConfigFS to locate active struct se_session
442 	 */
443 	se_nacl = se_sess->se_node_acl;
444 	if (se_nacl) {
445 		spin_lock_irqsave(&se_nacl->nacl_sess_lock, flags);
446 		if (se_nacl->acl_stop == 0)
447 			list_del(&se_sess->sess_acl_list);
448 		/*
449 		 * If the session list is empty, then clear the pointer.
450 		 * Otherwise, set the struct se_session pointer from the tail
451 		 * element of the per struct se_node_acl active session list.
452 		 */
453 		if (list_empty(&se_nacl->acl_sess_list))
454 			se_nacl->nacl_sess = NULL;
455 		else {
456 			se_nacl->nacl_sess = container_of(
457 					se_nacl->acl_sess_list.prev,
458 					struct se_session, sess_acl_list);
459 		}
460 		spin_unlock_irqrestore(&se_nacl->nacl_sess_lock, flags);
461 	}
462 }
463 EXPORT_SYMBOL(transport_deregister_session_configfs);
464 
465 void transport_free_session(struct se_session *se_sess)
466 {
467 	if (se_sess->sess_cmd_map) {
468 		percpu_ida_destroy(&se_sess->sess_tag_pool);
469 		kvfree(se_sess->sess_cmd_map);
470 	}
471 	kmem_cache_free(se_sess_cache, se_sess);
472 }
473 EXPORT_SYMBOL(transport_free_session);
474 
475 void transport_deregister_session(struct se_session *se_sess)
476 {
477 	struct se_portal_group *se_tpg = se_sess->se_tpg;
478 	const struct target_core_fabric_ops *se_tfo;
479 	struct se_node_acl *se_nacl;
480 	unsigned long flags;
481 	bool comp_nacl = true, drop_nacl = false;
482 
483 	if (!se_tpg) {
484 		transport_free_session(se_sess);
485 		return;
486 	}
487 	se_tfo = se_tpg->se_tpg_tfo;
488 
489 	spin_lock_irqsave(&se_tpg->session_lock, flags);
490 	list_del(&se_sess->sess_list);
491 	se_sess->se_tpg = NULL;
492 	se_sess->fabric_sess_ptr = NULL;
493 	spin_unlock_irqrestore(&se_tpg->session_lock, flags);
494 
495 	/*
496 	 * Determine if we need to do extra work for this initiator node's
497 	 * struct se_node_acl if it had been previously dynamically generated.
498 	 */
499 	se_nacl = se_sess->se_node_acl;
500 
501 	mutex_lock(&se_tpg->acl_node_mutex);
502 	if (se_nacl && se_nacl->dynamic_node_acl) {
503 		if (!se_tfo->tpg_check_demo_mode_cache(se_tpg)) {
504 			list_del(&se_nacl->acl_list);
505 			se_tpg->num_node_acls--;
506 			drop_nacl = true;
507 		}
508 	}
509 	mutex_unlock(&se_tpg->acl_node_mutex);
510 
511 	if (drop_nacl) {
512 		core_tpg_wait_for_nacl_pr_ref(se_nacl);
513 		core_free_device_list_for_node(se_nacl, se_tpg);
514 		kfree(se_nacl);
515 		comp_nacl = false;
516 	}
517 	pr_debug("TARGET_CORE[%s]: Deregistered fabric_sess\n",
518 		se_tpg->se_tpg_tfo->get_fabric_name());
519 	/*
520 	 * If last kref is dropping now for an explicit NodeACL, awake sleeping
521 	 * ->acl_free_comp caller to wakeup configfs se_node_acl->acl_group
522 	 * removal context.
523 	 */
524 	if (se_nacl && comp_nacl)
525 		target_put_nacl(se_nacl);
526 
527 	transport_free_session(se_sess);
528 }
529 EXPORT_SYMBOL(transport_deregister_session);
530 
531 /*
532  * Called with cmd->t_state_lock held.
533  */
534 static void target_remove_from_state_list(struct se_cmd *cmd)
535 {
536 	struct se_device *dev = cmd->se_dev;
537 	unsigned long flags;
538 
539 	if (!dev)
540 		return;
541 
542 	if (cmd->transport_state & CMD_T_BUSY)
543 		return;
544 
545 	spin_lock_irqsave(&dev->execute_task_lock, flags);
546 	if (cmd->state_active) {
547 		list_del(&cmd->state_list);
548 		cmd->state_active = false;
549 	}
550 	spin_unlock_irqrestore(&dev->execute_task_lock, flags);
551 }
552 
553 static int transport_cmd_check_stop(struct se_cmd *cmd, bool remove_from_lists,
554 				    bool write_pending)
555 {
556 	unsigned long flags;
557 
558 	spin_lock_irqsave(&cmd->t_state_lock, flags);
559 	if (write_pending)
560 		cmd->t_state = TRANSPORT_WRITE_PENDING;
561 
562 	if (remove_from_lists) {
563 		target_remove_from_state_list(cmd);
564 
565 		/*
566 		 * Clear struct se_cmd->se_lun before the handoff to FE.
567 		 */
568 		cmd->se_lun = NULL;
569 	}
570 
571 	/*
572 	 * Determine if frontend context caller is requesting the stopping of
573 	 * this command for frontend exceptions.
574 	 */
575 	if (cmd->transport_state & CMD_T_STOP) {
576 		pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08llx\n",
577 			__func__, __LINE__, cmd->tag);
578 
579 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
580 
581 		complete_all(&cmd->t_transport_stop_comp);
582 		return 1;
583 	}
584 
585 	cmd->transport_state &= ~CMD_T_ACTIVE;
586 	if (remove_from_lists) {
587 		/*
588 		 * Some fabric modules like tcm_loop can release
589 		 * their internally allocated I/O reference now and
590 		 * struct se_cmd now.
591 		 *
592 		 * Fabric modules are expected to return '1' here if the
593 		 * se_cmd being passed is released at this point,
594 		 * or zero if not being released.
595 		 */
596 		if (cmd->se_tfo->check_stop_free != NULL) {
597 			spin_unlock_irqrestore(&cmd->t_state_lock, flags);
598 			return cmd->se_tfo->check_stop_free(cmd);
599 		}
600 	}
601 
602 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
603 	return 0;
604 }
605 
606 static int transport_cmd_check_stop_to_fabric(struct se_cmd *cmd)
607 {
608 	return transport_cmd_check_stop(cmd, true, false);
609 }
610 
611 static void transport_lun_remove_cmd(struct se_cmd *cmd)
612 {
613 	struct se_lun *lun = cmd->se_lun;
614 
615 	if (!lun)
616 		return;
617 
618 	if (cmpxchg(&cmd->lun_ref_active, true, false))
619 		percpu_ref_put(&lun->lun_ref);
620 }
621 
622 void transport_cmd_finish_abort(struct se_cmd *cmd, int remove)
623 {
624 	if (cmd->se_cmd_flags & SCF_SE_LUN_CMD)
625 		transport_lun_remove_cmd(cmd);
626 	/*
627 	 * Allow the fabric driver to unmap any resources before
628 	 * releasing the descriptor via TFO->release_cmd()
629 	 */
630 	if (remove)
631 		cmd->se_tfo->aborted_task(cmd);
632 
633 	if (transport_cmd_check_stop_to_fabric(cmd))
634 		return;
635 	if (remove)
636 		transport_put_cmd(cmd);
637 }
638 
639 static void target_complete_failure_work(struct work_struct *work)
640 {
641 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
642 
643 	transport_generic_request_failure(cmd,
644 			TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE);
645 }
646 
647 /*
648  * Used when asking transport to copy Sense Data from the underlying
649  * Linux/SCSI struct scsi_cmnd
650  */
651 static unsigned char *transport_get_sense_buffer(struct se_cmd *cmd)
652 {
653 	struct se_device *dev = cmd->se_dev;
654 
655 	WARN_ON(!cmd->se_lun);
656 
657 	if (!dev)
658 		return NULL;
659 
660 	if (cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION)
661 		return NULL;
662 
663 	cmd->scsi_sense_length = TRANSPORT_SENSE_BUFFER;
664 
665 	pr_debug("HBA_[%u]_PLUG[%s]: Requesting sense for SAM STATUS: 0x%02x\n",
666 		dev->se_hba->hba_id, dev->transport->name, cmd->scsi_status);
667 	return cmd->sense_buffer;
668 }
669 
670 void target_complete_cmd(struct se_cmd *cmd, u8 scsi_status)
671 {
672 	struct se_device *dev = cmd->se_dev;
673 	int success = scsi_status == GOOD;
674 	unsigned long flags;
675 
676 	cmd->scsi_status = scsi_status;
677 
678 
679 	spin_lock_irqsave(&cmd->t_state_lock, flags);
680 	cmd->transport_state &= ~CMD_T_BUSY;
681 
682 	if (dev && dev->transport->transport_complete) {
683 		dev->transport->transport_complete(cmd,
684 				cmd->t_data_sg,
685 				transport_get_sense_buffer(cmd));
686 		if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE)
687 			success = 1;
688 	}
689 
690 	/*
691 	 * See if we are waiting to complete for an exception condition.
692 	 */
693 	if (cmd->transport_state & CMD_T_REQUEST_STOP) {
694 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
695 		complete(&cmd->task_stop_comp);
696 		return;
697 	}
698 
699 	/*
700 	 * Check for case where an explicit ABORT_TASK has been received
701 	 * and transport_wait_for_tasks() will be waiting for completion..
702 	 */
703 	if (cmd->transport_state & CMD_T_ABORTED &&
704 	    cmd->transport_state & CMD_T_STOP) {
705 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
706 		complete_all(&cmd->t_transport_stop_comp);
707 		return;
708 	} else if (!success) {
709 		INIT_WORK(&cmd->work, target_complete_failure_work);
710 	} else {
711 		INIT_WORK(&cmd->work, target_complete_ok_work);
712 	}
713 
714 	cmd->t_state = TRANSPORT_COMPLETE;
715 	cmd->transport_state |= (CMD_T_COMPLETE | CMD_T_ACTIVE);
716 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
717 
718 	queue_work(target_completion_wq, &cmd->work);
719 }
720 EXPORT_SYMBOL(target_complete_cmd);
721 
722 void target_complete_cmd_with_length(struct se_cmd *cmd, u8 scsi_status, int length)
723 {
724 	if (scsi_status == SAM_STAT_GOOD && length < cmd->data_length) {
725 		if (cmd->se_cmd_flags & SCF_UNDERFLOW_BIT) {
726 			cmd->residual_count += cmd->data_length - length;
727 		} else {
728 			cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
729 			cmd->residual_count = cmd->data_length - length;
730 		}
731 
732 		cmd->data_length = length;
733 	}
734 
735 	target_complete_cmd(cmd, scsi_status);
736 }
737 EXPORT_SYMBOL(target_complete_cmd_with_length);
738 
739 static void target_add_to_state_list(struct se_cmd *cmd)
740 {
741 	struct se_device *dev = cmd->se_dev;
742 	unsigned long flags;
743 
744 	spin_lock_irqsave(&dev->execute_task_lock, flags);
745 	if (!cmd->state_active) {
746 		list_add_tail(&cmd->state_list, &dev->state_list);
747 		cmd->state_active = true;
748 	}
749 	spin_unlock_irqrestore(&dev->execute_task_lock, flags);
750 }
751 
752 /*
753  * Handle QUEUE_FULL / -EAGAIN and -ENOMEM status
754  */
755 static void transport_write_pending_qf(struct se_cmd *cmd);
756 static void transport_complete_qf(struct se_cmd *cmd);
757 
758 void target_qf_do_work(struct work_struct *work)
759 {
760 	struct se_device *dev = container_of(work, struct se_device,
761 					qf_work_queue);
762 	LIST_HEAD(qf_cmd_list);
763 	struct se_cmd *cmd, *cmd_tmp;
764 
765 	spin_lock_irq(&dev->qf_cmd_lock);
766 	list_splice_init(&dev->qf_cmd_list, &qf_cmd_list);
767 	spin_unlock_irq(&dev->qf_cmd_lock);
768 
769 	list_for_each_entry_safe(cmd, cmd_tmp, &qf_cmd_list, se_qf_node) {
770 		list_del(&cmd->se_qf_node);
771 		atomic_dec_mb(&dev->dev_qf_count);
772 
773 		pr_debug("Processing %s cmd: %p QUEUE_FULL in work queue"
774 			" context: %s\n", cmd->se_tfo->get_fabric_name(), cmd,
775 			(cmd->t_state == TRANSPORT_COMPLETE_QF_OK) ? "COMPLETE_OK" :
776 			(cmd->t_state == TRANSPORT_COMPLETE_QF_WP) ? "WRITE_PENDING"
777 			: "UNKNOWN");
778 
779 		if (cmd->t_state == TRANSPORT_COMPLETE_QF_WP)
780 			transport_write_pending_qf(cmd);
781 		else if (cmd->t_state == TRANSPORT_COMPLETE_QF_OK)
782 			transport_complete_qf(cmd);
783 	}
784 }
785 
786 unsigned char *transport_dump_cmd_direction(struct se_cmd *cmd)
787 {
788 	switch (cmd->data_direction) {
789 	case DMA_NONE:
790 		return "NONE";
791 	case DMA_FROM_DEVICE:
792 		return "READ";
793 	case DMA_TO_DEVICE:
794 		return "WRITE";
795 	case DMA_BIDIRECTIONAL:
796 		return "BIDI";
797 	default:
798 		break;
799 	}
800 
801 	return "UNKNOWN";
802 }
803 
804 void transport_dump_dev_state(
805 	struct se_device *dev,
806 	char *b,
807 	int *bl)
808 {
809 	*bl += sprintf(b + *bl, "Status: ");
810 	if (dev->export_count)
811 		*bl += sprintf(b + *bl, "ACTIVATED");
812 	else
813 		*bl += sprintf(b + *bl, "DEACTIVATED");
814 
815 	*bl += sprintf(b + *bl, "  Max Queue Depth: %d", dev->queue_depth);
816 	*bl += sprintf(b + *bl, "  SectorSize: %u  HwMaxSectors: %u\n",
817 		dev->dev_attrib.block_size,
818 		dev->dev_attrib.hw_max_sectors);
819 	*bl += sprintf(b + *bl, "        ");
820 }
821 
822 void transport_dump_vpd_proto_id(
823 	struct t10_vpd *vpd,
824 	unsigned char *p_buf,
825 	int p_buf_len)
826 {
827 	unsigned char buf[VPD_TMP_BUF_SIZE];
828 	int len;
829 
830 	memset(buf, 0, VPD_TMP_BUF_SIZE);
831 	len = sprintf(buf, "T10 VPD Protocol Identifier: ");
832 
833 	switch (vpd->protocol_identifier) {
834 	case 0x00:
835 		sprintf(buf+len, "Fibre Channel\n");
836 		break;
837 	case 0x10:
838 		sprintf(buf+len, "Parallel SCSI\n");
839 		break;
840 	case 0x20:
841 		sprintf(buf+len, "SSA\n");
842 		break;
843 	case 0x30:
844 		sprintf(buf+len, "IEEE 1394\n");
845 		break;
846 	case 0x40:
847 		sprintf(buf+len, "SCSI Remote Direct Memory Access"
848 				" Protocol\n");
849 		break;
850 	case 0x50:
851 		sprintf(buf+len, "Internet SCSI (iSCSI)\n");
852 		break;
853 	case 0x60:
854 		sprintf(buf+len, "SAS Serial SCSI Protocol\n");
855 		break;
856 	case 0x70:
857 		sprintf(buf+len, "Automation/Drive Interface Transport"
858 				" Protocol\n");
859 		break;
860 	case 0x80:
861 		sprintf(buf+len, "AT Attachment Interface ATA/ATAPI\n");
862 		break;
863 	default:
864 		sprintf(buf+len, "Unknown 0x%02x\n",
865 				vpd->protocol_identifier);
866 		break;
867 	}
868 
869 	if (p_buf)
870 		strncpy(p_buf, buf, p_buf_len);
871 	else
872 		pr_debug("%s", buf);
873 }
874 
875 void
876 transport_set_vpd_proto_id(struct t10_vpd *vpd, unsigned char *page_83)
877 {
878 	/*
879 	 * Check if the Protocol Identifier Valid (PIV) bit is set..
880 	 *
881 	 * from spc3r23.pdf section 7.5.1
882 	 */
883 	 if (page_83[1] & 0x80) {
884 		vpd->protocol_identifier = (page_83[0] & 0xf0);
885 		vpd->protocol_identifier_set = 1;
886 		transport_dump_vpd_proto_id(vpd, NULL, 0);
887 	}
888 }
889 EXPORT_SYMBOL(transport_set_vpd_proto_id);
890 
891 int transport_dump_vpd_assoc(
892 	struct t10_vpd *vpd,
893 	unsigned char *p_buf,
894 	int p_buf_len)
895 {
896 	unsigned char buf[VPD_TMP_BUF_SIZE];
897 	int ret = 0;
898 	int len;
899 
900 	memset(buf, 0, VPD_TMP_BUF_SIZE);
901 	len = sprintf(buf, "T10 VPD Identifier Association: ");
902 
903 	switch (vpd->association) {
904 	case 0x00:
905 		sprintf(buf+len, "addressed logical unit\n");
906 		break;
907 	case 0x10:
908 		sprintf(buf+len, "target port\n");
909 		break;
910 	case 0x20:
911 		sprintf(buf+len, "SCSI target device\n");
912 		break;
913 	default:
914 		sprintf(buf+len, "Unknown 0x%02x\n", vpd->association);
915 		ret = -EINVAL;
916 		break;
917 	}
918 
919 	if (p_buf)
920 		strncpy(p_buf, buf, p_buf_len);
921 	else
922 		pr_debug("%s", buf);
923 
924 	return ret;
925 }
926 
927 int transport_set_vpd_assoc(struct t10_vpd *vpd, unsigned char *page_83)
928 {
929 	/*
930 	 * The VPD identification association..
931 	 *
932 	 * from spc3r23.pdf Section 7.6.3.1 Table 297
933 	 */
934 	vpd->association = (page_83[1] & 0x30);
935 	return transport_dump_vpd_assoc(vpd, NULL, 0);
936 }
937 EXPORT_SYMBOL(transport_set_vpd_assoc);
938 
939 int transport_dump_vpd_ident_type(
940 	struct t10_vpd *vpd,
941 	unsigned char *p_buf,
942 	int p_buf_len)
943 {
944 	unsigned char buf[VPD_TMP_BUF_SIZE];
945 	int ret = 0;
946 	int len;
947 
948 	memset(buf, 0, VPD_TMP_BUF_SIZE);
949 	len = sprintf(buf, "T10 VPD Identifier Type: ");
950 
951 	switch (vpd->device_identifier_type) {
952 	case 0x00:
953 		sprintf(buf+len, "Vendor specific\n");
954 		break;
955 	case 0x01:
956 		sprintf(buf+len, "T10 Vendor ID based\n");
957 		break;
958 	case 0x02:
959 		sprintf(buf+len, "EUI-64 based\n");
960 		break;
961 	case 0x03:
962 		sprintf(buf+len, "NAA\n");
963 		break;
964 	case 0x04:
965 		sprintf(buf+len, "Relative target port identifier\n");
966 		break;
967 	case 0x08:
968 		sprintf(buf+len, "SCSI name string\n");
969 		break;
970 	default:
971 		sprintf(buf+len, "Unsupported: 0x%02x\n",
972 				vpd->device_identifier_type);
973 		ret = -EINVAL;
974 		break;
975 	}
976 
977 	if (p_buf) {
978 		if (p_buf_len < strlen(buf)+1)
979 			return -EINVAL;
980 		strncpy(p_buf, buf, p_buf_len);
981 	} else {
982 		pr_debug("%s", buf);
983 	}
984 
985 	return ret;
986 }
987 
988 int transport_set_vpd_ident_type(struct t10_vpd *vpd, unsigned char *page_83)
989 {
990 	/*
991 	 * The VPD identifier type..
992 	 *
993 	 * from spc3r23.pdf Section 7.6.3.1 Table 298
994 	 */
995 	vpd->device_identifier_type = (page_83[1] & 0x0f);
996 	return transport_dump_vpd_ident_type(vpd, NULL, 0);
997 }
998 EXPORT_SYMBOL(transport_set_vpd_ident_type);
999 
1000 int transport_dump_vpd_ident(
1001 	struct t10_vpd *vpd,
1002 	unsigned char *p_buf,
1003 	int p_buf_len)
1004 {
1005 	unsigned char buf[VPD_TMP_BUF_SIZE];
1006 	int ret = 0;
1007 
1008 	memset(buf, 0, VPD_TMP_BUF_SIZE);
1009 
1010 	switch (vpd->device_identifier_code_set) {
1011 	case 0x01: /* Binary */
1012 		snprintf(buf, sizeof(buf),
1013 			"T10 VPD Binary Device Identifier: %s\n",
1014 			&vpd->device_identifier[0]);
1015 		break;
1016 	case 0x02: /* ASCII */
1017 		snprintf(buf, sizeof(buf),
1018 			"T10 VPD ASCII Device Identifier: %s\n",
1019 			&vpd->device_identifier[0]);
1020 		break;
1021 	case 0x03: /* UTF-8 */
1022 		snprintf(buf, sizeof(buf),
1023 			"T10 VPD UTF-8 Device Identifier: %s\n",
1024 			&vpd->device_identifier[0]);
1025 		break;
1026 	default:
1027 		sprintf(buf, "T10 VPD Device Identifier encoding unsupported:"
1028 			" 0x%02x", vpd->device_identifier_code_set);
1029 		ret = -EINVAL;
1030 		break;
1031 	}
1032 
1033 	if (p_buf)
1034 		strncpy(p_buf, buf, p_buf_len);
1035 	else
1036 		pr_debug("%s", buf);
1037 
1038 	return ret;
1039 }
1040 
1041 int
1042 transport_set_vpd_ident(struct t10_vpd *vpd, unsigned char *page_83)
1043 {
1044 	static const char hex_str[] = "0123456789abcdef";
1045 	int j = 0, i = 4; /* offset to start of the identifier */
1046 
1047 	/*
1048 	 * The VPD Code Set (encoding)
1049 	 *
1050 	 * from spc3r23.pdf Section 7.6.3.1 Table 296
1051 	 */
1052 	vpd->device_identifier_code_set = (page_83[0] & 0x0f);
1053 	switch (vpd->device_identifier_code_set) {
1054 	case 0x01: /* Binary */
1055 		vpd->device_identifier[j++] =
1056 				hex_str[vpd->device_identifier_type];
1057 		while (i < (4 + page_83[3])) {
1058 			vpd->device_identifier[j++] =
1059 				hex_str[(page_83[i] & 0xf0) >> 4];
1060 			vpd->device_identifier[j++] =
1061 				hex_str[page_83[i] & 0x0f];
1062 			i++;
1063 		}
1064 		break;
1065 	case 0x02: /* ASCII */
1066 	case 0x03: /* UTF-8 */
1067 		while (i < (4 + page_83[3]))
1068 			vpd->device_identifier[j++] = page_83[i++];
1069 		break;
1070 	default:
1071 		break;
1072 	}
1073 
1074 	return transport_dump_vpd_ident(vpd, NULL, 0);
1075 }
1076 EXPORT_SYMBOL(transport_set_vpd_ident);
1077 
1078 static sense_reason_t
1079 target_check_max_data_sg_nents(struct se_cmd *cmd, struct se_device *dev,
1080 			       unsigned int size)
1081 {
1082 	u32 mtl;
1083 
1084 	if (!cmd->se_tfo->max_data_sg_nents)
1085 		return TCM_NO_SENSE;
1086 	/*
1087 	 * Check if fabric enforced maximum SGL entries per I/O descriptor
1088 	 * exceeds se_cmd->data_length.  If true, set SCF_UNDERFLOW_BIT +
1089 	 * residual_count and reduce original cmd->data_length to maximum
1090 	 * length based on single PAGE_SIZE entry scatter-lists.
1091 	 */
1092 	mtl = (cmd->se_tfo->max_data_sg_nents * PAGE_SIZE);
1093 	if (cmd->data_length > mtl) {
1094 		/*
1095 		 * If an existing CDB overflow is present, calculate new residual
1096 		 * based on CDB size minus fabric maximum transfer length.
1097 		 *
1098 		 * If an existing CDB underflow is present, calculate new residual
1099 		 * based on original cmd->data_length minus fabric maximum transfer
1100 		 * length.
1101 		 *
1102 		 * Otherwise, set the underflow residual based on cmd->data_length
1103 		 * minus fabric maximum transfer length.
1104 		 */
1105 		if (cmd->se_cmd_flags & SCF_OVERFLOW_BIT) {
1106 			cmd->residual_count = (size - mtl);
1107 		} else if (cmd->se_cmd_flags & SCF_UNDERFLOW_BIT) {
1108 			u32 orig_dl = size + cmd->residual_count;
1109 			cmd->residual_count = (orig_dl - mtl);
1110 		} else {
1111 			cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
1112 			cmd->residual_count = (cmd->data_length - mtl);
1113 		}
1114 		cmd->data_length = mtl;
1115 		/*
1116 		 * Reset sbc_check_prot() calculated protection payload
1117 		 * length based upon the new smaller MTL.
1118 		 */
1119 		if (cmd->prot_length) {
1120 			u32 sectors = (mtl / dev->dev_attrib.block_size);
1121 			cmd->prot_length = dev->prot_length * sectors;
1122 		}
1123 	}
1124 	return TCM_NO_SENSE;
1125 }
1126 
1127 sense_reason_t
1128 target_cmd_size_check(struct se_cmd *cmd, unsigned int size)
1129 {
1130 	struct se_device *dev = cmd->se_dev;
1131 
1132 	if (cmd->unknown_data_length) {
1133 		cmd->data_length = size;
1134 	} else if (size != cmd->data_length) {
1135 		pr_warn("TARGET_CORE[%s]: Expected Transfer Length:"
1136 			" %u does not match SCSI CDB Length: %u for SAM Opcode:"
1137 			" 0x%02x\n", cmd->se_tfo->get_fabric_name(),
1138 				cmd->data_length, size, cmd->t_task_cdb[0]);
1139 
1140 		if (cmd->data_direction == DMA_TO_DEVICE &&
1141 		    cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) {
1142 			pr_err("Rejecting underflow/overflow WRITE data\n");
1143 			return TCM_INVALID_CDB_FIELD;
1144 		}
1145 		/*
1146 		 * Reject READ_* or WRITE_* with overflow/underflow for
1147 		 * type SCF_SCSI_DATA_CDB.
1148 		 */
1149 		if (dev->dev_attrib.block_size != 512)  {
1150 			pr_err("Failing OVERFLOW/UNDERFLOW for LBA op"
1151 				" CDB on non 512-byte sector setup subsystem"
1152 				" plugin: %s\n", dev->transport->name);
1153 			/* Returns CHECK_CONDITION + INVALID_CDB_FIELD */
1154 			return TCM_INVALID_CDB_FIELD;
1155 		}
1156 		/*
1157 		 * For the overflow case keep the existing fabric provided
1158 		 * ->data_length.  Otherwise for the underflow case, reset
1159 		 * ->data_length to the smaller SCSI expected data transfer
1160 		 * length.
1161 		 */
1162 		if (size > cmd->data_length) {
1163 			cmd->se_cmd_flags |= SCF_OVERFLOW_BIT;
1164 			cmd->residual_count = (size - cmd->data_length);
1165 		} else {
1166 			cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
1167 			cmd->residual_count = (cmd->data_length - size);
1168 			cmd->data_length = size;
1169 		}
1170 	}
1171 
1172 	return target_check_max_data_sg_nents(cmd, dev, size);
1173 
1174 }
1175 
1176 /*
1177  * Used by fabric modules containing a local struct se_cmd within their
1178  * fabric dependent per I/O descriptor.
1179  *
1180  * Preserves the value of @cmd->tag.
1181  */
1182 void transport_init_se_cmd(
1183 	struct se_cmd *cmd,
1184 	const struct target_core_fabric_ops *tfo,
1185 	struct se_session *se_sess,
1186 	u32 data_length,
1187 	int data_direction,
1188 	int task_attr,
1189 	unsigned char *sense_buffer)
1190 {
1191 	INIT_LIST_HEAD(&cmd->se_delayed_node);
1192 	INIT_LIST_HEAD(&cmd->se_qf_node);
1193 	INIT_LIST_HEAD(&cmd->se_cmd_list);
1194 	INIT_LIST_HEAD(&cmd->state_list);
1195 	init_completion(&cmd->t_transport_stop_comp);
1196 	init_completion(&cmd->cmd_wait_comp);
1197 	init_completion(&cmd->task_stop_comp);
1198 	spin_lock_init(&cmd->t_state_lock);
1199 	kref_init(&cmd->cmd_kref);
1200 	cmd->transport_state = CMD_T_DEV_ACTIVE;
1201 
1202 	cmd->se_tfo = tfo;
1203 	cmd->se_sess = se_sess;
1204 	cmd->data_length = data_length;
1205 	cmd->data_direction = data_direction;
1206 	cmd->sam_task_attr = task_attr;
1207 	cmd->sense_buffer = sense_buffer;
1208 
1209 	cmd->state_active = false;
1210 }
1211 EXPORT_SYMBOL(transport_init_se_cmd);
1212 
1213 static sense_reason_t
1214 transport_check_alloc_task_attr(struct se_cmd *cmd)
1215 {
1216 	struct se_device *dev = cmd->se_dev;
1217 
1218 	/*
1219 	 * Check if SAM Task Attribute emulation is enabled for this
1220 	 * struct se_device storage object
1221 	 */
1222 	if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
1223 		return 0;
1224 
1225 	if (cmd->sam_task_attr == TCM_ACA_TAG) {
1226 		pr_debug("SAM Task Attribute ACA"
1227 			" emulation is not supported\n");
1228 		return TCM_INVALID_CDB_FIELD;
1229 	}
1230 
1231 	return 0;
1232 }
1233 
1234 sense_reason_t
1235 target_setup_cmd_from_cdb(struct se_cmd *cmd, unsigned char *cdb)
1236 {
1237 	struct se_device *dev = cmd->se_dev;
1238 	sense_reason_t ret;
1239 
1240 	/*
1241 	 * Ensure that the received CDB is less than the max (252 + 8) bytes
1242 	 * for VARIABLE_LENGTH_CMD
1243 	 */
1244 	if (scsi_command_size(cdb) > SCSI_MAX_VARLEN_CDB_SIZE) {
1245 		pr_err("Received SCSI CDB with command_size: %d that"
1246 			" exceeds SCSI_MAX_VARLEN_CDB_SIZE: %d\n",
1247 			scsi_command_size(cdb), SCSI_MAX_VARLEN_CDB_SIZE);
1248 		return TCM_INVALID_CDB_FIELD;
1249 	}
1250 	/*
1251 	 * If the received CDB is larger than TCM_MAX_COMMAND_SIZE,
1252 	 * allocate the additional extended CDB buffer now..  Otherwise
1253 	 * setup the pointer from __t_task_cdb to t_task_cdb.
1254 	 */
1255 	if (scsi_command_size(cdb) > sizeof(cmd->__t_task_cdb)) {
1256 		cmd->t_task_cdb = kzalloc(scsi_command_size(cdb),
1257 						GFP_KERNEL);
1258 		if (!cmd->t_task_cdb) {
1259 			pr_err("Unable to allocate cmd->t_task_cdb"
1260 				" %u > sizeof(cmd->__t_task_cdb): %lu ops\n",
1261 				scsi_command_size(cdb),
1262 				(unsigned long)sizeof(cmd->__t_task_cdb));
1263 			return TCM_OUT_OF_RESOURCES;
1264 		}
1265 	} else
1266 		cmd->t_task_cdb = &cmd->__t_task_cdb[0];
1267 	/*
1268 	 * Copy the original CDB into cmd->
1269 	 */
1270 	memcpy(cmd->t_task_cdb, cdb, scsi_command_size(cdb));
1271 
1272 	trace_target_sequencer_start(cmd);
1273 
1274 	/*
1275 	 * Check for an existing UNIT ATTENTION condition
1276 	 */
1277 	ret = target_scsi3_ua_check(cmd);
1278 	if (ret)
1279 		return ret;
1280 
1281 	ret = target_alua_state_check(cmd);
1282 	if (ret)
1283 		return ret;
1284 
1285 	ret = target_check_reservation(cmd);
1286 	if (ret) {
1287 		cmd->scsi_status = SAM_STAT_RESERVATION_CONFLICT;
1288 		return ret;
1289 	}
1290 
1291 	ret = dev->transport->parse_cdb(cmd);
1292 	if (ret == TCM_UNSUPPORTED_SCSI_OPCODE)
1293 		pr_warn_ratelimited("%s/%s: Unsupported SCSI Opcode 0x%02x, sending CHECK_CONDITION.\n",
1294 				    cmd->se_tfo->get_fabric_name(),
1295 				    cmd->se_sess->se_node_acl->initiatorname,
1296 				    cmd->t_task_cdb[0]);
1297 	if (ret)
1298 		return ret;
1299 
1300 	ret = transport_check_alloc_task_attr(cmd);
1301 	if (ret)
1302 		return ret;
1303 
1304 	cmd->se_cmd_flags |= SCF_SUPPORTED_SAM_OPCODE;
1305 	atomic_long_inc(&cmd->se_lun->lun_stats.cmd_pdus);
1306 	return 0;
1307 }
1308 EXPORT_SYMBOL(target_setup_cmd_from_cdb);
1309 
1310 /*
1311  * Used by fabric module frontends to queue tasks directly.
1312  * Many only be used from process context only
1313  */
1314 int transport_handle_cdb_direct(
1315 	struct se_cmd *cmd)
1316 {
1317 	sense_reason_t ret;
1318 
1319 	if (!cmd->se_lun) {
1320 		dump_stack();
1321 		pr_err("cmd->se_lun is NULL\n");
1322 		return -EINVAL;
1323 	}
1324 	if (in_interrupt()) {
1325 		dump_stack();
1326 		pr_err("transport_generic_handle_cdb cannot be called"
1327 				" from interrupt context\n");
1328 		return -EINVAL;
1329 	}
1330 	/*
1331 	 * Set TRANSPORT_NEW_CMD state and CMD_T_ACTIVE to ensure that
1332 	 * outstanding descriptors are handled correctly during shutdown via
1333 	 * transport_wait_for_tasks()
1334 	 *
1335 	 * Also, we don't take cmd->t_state_lock here as we only expect
1336 	 * this to be called for initial descriptor submission.
1337 	 */
1338 	cmd->t_state = TRANSPORT_NEW_CMD;
1339 	cmd->transport_state |= CMD_T_ACTIVE;
1340 
1341 	/*
1342 	 * transport_generic_new_cmd() is already handling QUEUE_FULL,
1343 	 * so follow TRANSPORT_NEW_CMD processing thread context usage
1344 	 * and call transport_generic_request_failure() if necessary..
1345 	 */
1346 	ret = transport_generic_new_cmd(cmd);
1347 	if (ret)
1348 		transport_generic_request_failure(cmd, ret);
1349 	return 0;
1350 }
1351 EXPORT_SYMBOL(transport_handle_cdb_direct);
1352 
1353 sense_reason_t
1354 transport_generic_map_mem_to_cmd(struct se_cmd *cmd, struct scatterlist *sgl,
1355 		u32 sgl_count, struct scatterlist *sgl_bidi, u32 sgl_bidi_count)
1356 {
1357 	if (!sgl || !sgl_count)
1358 		return 0;
1359 
1360 	/*
1361 	 * Reject SCSI data overflow with map_mem_to_cmd() as incoming
1362 	 * scatterlists already have been set to follow what the fabric
1363 	 * passes for the original expected data transfer length.
1364 	 */
1365 	if (cmd->se_cmd_flags & SCF_OVERFLOW_BIT) {
1366 		pr_warn("Rejecting SCSI DATA overflow for fabric using"
1367 			" SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC\n");
1368 		return TCM_INVALID_CDB_FIELD;
1369 	}
1370 
1371 	cmd->t_data_sg = sgl;
1372 	cmd->t_data_nents = sgl_count;
1373 	cmd->t_bidi_data_sg = sgl_bidi;
1374 	cmd->t_bidi_data_nents = sgl_bidi_count;
1375 
1376 	cmd->se_cmd_flags |= SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC;
1377 	return 0;
1378 }
1379 
1380 /*
1381  * target_submit_cmd_map_sgls - lookup unpacked lun and submit uninitialized
1382  * 			 se_cmd + use pre-allocated SGL memory.
1383  *
1384  * @se_cmd: command descriptor to submit
1385  * @se_sess: associated se_sess for endpoint
1386  * @cdb: pointer to SCSI CDB
1387  * @sense: pointer to SCSI sense buffer
1388  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1389  * @data_length: fabric expected data transfer length
1390  * @task_addr: SAM task attribute
1391  * @data_dir: DMA data direction
1392  * @flags: flags for command submission from target_sc_flags_tables
1393  * @sgl: struct scatterlist memory for unidirectional mapping
1394  * @sgl_count: scatterlist count for unidirectional mapping
1395  * @sgl_bidi: struct scatterlist memory for bidirectional READ mapping
1396  * @sgl_bidi_count: scatterlist count for bidirectional READ mapping
1397  * @sgl_prot: struct scatterlist memory protection information
1398  * @sgl_prot_count: scatterlist count for protection information
1399  *
1400  * Task tags are supported if the caller has set @se_cmd->tag.
1401  *
1402  * Returns non zero to signal active I/O shutdown failure.  All other
1403  * setup exceptions will be returned as a SCSI CHECK_CONDITION response,
1404  * but still return zero here.
1405  *
1406  * This may only be called from process context, and also currently
1407  * assumes internal allocation of fabric payload buffer by target-core.
1408  */
1409 int target_submit_cmd_map_sgls(struct se_cmd *se_cmd, struct se_session *se_sess,
1410 		unsigned char *cdb, unsigned char *sense, u64 unpacked_lun,
1411 		u32 data_length, int task_attr, int data_dir, int flags,
1412 		struct scatterlist *sgl, u32 sgl_count,
1413 		struct scatterlist *sgl_bidi, u32 sgl_bidi_count,
1414 		struct scatterlist *sgl_prot, u32 sgl_prot_count)
1415 {
1416 	struct se_portal_group *se_tpg;
1417 	sense_reason_t rc;
1418 	int ret;
1419 
1420 	se_tpg = se_sess->se_tpg;
1421 	BUG_ON(!se_tpg);
1422 	BUG_ON(se_cmd->se_tfo || se_cmd->se_sess);
1423 	BUG_ON(in_interrupt());
1424 	/*
1425 	 * Initialize se_cmd for target operation.  From this point
1426 	 * exceptions are handled by sending exception status via
1427 	 * target_core_fabric_ops->queue_status() callback
1428 	 */
1429 	transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess,
1430 				data_length, data_dir, task_attr, sense);
1431 	if (flags & TARGET_SCF_UNKNOWN_SIZE)
1432 		se_cmd->unknown_data_length = 1;
1433 	/*
1434 	 * Obtain struct se_cmd->cmd_kref reference and add new cmd to
1435 	 * se_sess->sess_cmd_list.  A second kref_get here is necessary
1436 	 * for fabrics using TARGET_SCF_ACK_KREF that expect a second
1437 	 * kref_put() to happen during fabric packet acknowledgement.
1438 	 */
1439 	ret = target_get_sess_cmd(se_cmd, flags & TARGET_SCF_ACK_KREF);
1440 	if (ret)
1441 		return ret;
1442 	/*
1443 	 * Signal bidirectional data payloads to target-core
1444 	 */
1445 	if (flags & TARGET_SCF_BIDI_OP)
1446 		se_cmd->se_cmd_flags |= SCF_BIDI;
1447 	/*
1448 	 * Locate se_lun pointer and attach it to struct se_cmd
1449 	 */
1450 	rc = transport_lookup_cmd_lun(se_cmd, unpacked_lun);
1451 	if (rc) {
1452 		transport_send_check_condition_and_sense(se_cmd, rc, 0);
1453 		target_put_sess_cmd(se_cmd);
1454 		return 0;
1455 	}
1456 
1457 	rc = target_setup_cmd_from_cdb(se_cmd, cdb);
1458 	if (rc != 0) {
1459 		transport_generic_request_failure(se_cmd, rc);
1460 		return 0;
1461 	}
1462 
1463 	/*
1464 	 * Save pointers for SGLs containing protection information,
1465 	 * if present.
1466 	 */
1467 	if (sgl_prot_count) {
1468 		se_cmd->t_prot_sg = sgl_prot;
1469 		se_cmd->t_prot_nents = sgl_prot_count;
1470 		se_cmd->se_cmd_flags |= SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC;
1471 	}
1472 
1473 	/*
1474 	 * When a non zero sgl_count has been passed perform SGL passthrough
1475 	 * mapping for pre-allocated fabric memory instead of having target
1476 	 * core perform an internal SGL allocation..
1477 	 */
1478 	if (sgl_count != 0) {
1479 		BUG_ON(!sgl);
1480 
1481 		/*
1482 		 * A work-around for tcm_loop as some userspace code via
1483 		 * scsi-generic do not memset their associated read buffers,
1484 		 * so go ahead and do that here for type non-data CDBs.  Also
1485 		 * note that this is currently guaranteed to be a single SGL
1486 		 * for this case by target core in target_setup_cmd_from_cdb()
1487 		 * -> transport_generic_cmd_sequencer().
1488 		 */
1489 		if (!(se_cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) &&
1490 		     se_cmd->data_direction == DMA_FROM_DEVICE) {
1491 			unsigned char *buf = NULL;
1492 
1493 			if (sgl)
1494 				buf = kmap(sg_page(sgl)) + sgl->offset;
1495 
1496 			if (buf) {
1497 				memset(buf, 0, sgl->length);
1498 				kunmap(sg_page(sgl));
1499 			}
1500 		}
1501 
1502 		rc = transport_generic_map_mem_to_cmd(se_cmd, sgl, sgl_count,
1503 				sgl_bidi, sgl_bidi_count);
1504 		if (rc != 0) {
1505 			transport_generic_request_failure(se_cmd, rc);
1506 			return 0;
1507 		}
1508 	}
1509 
1510 	/*
1511 	 * Check if we need to delay processing because of ALUA
1512 	 * Active/NonOptimized primary access state..
1513 	 */
1514 	core_alua_check_nonop_delay(se_cmd);
1515 
1516 	transport_handle_cdb_direct(se_cmd);
1517 	return 0;
1518 }
1519 EXPORT_SYMBOL(target_submit_cmd_map_sgls);
1520 
1521 /*
1522  * target_submit_cmd - lookup unpacked lun and submit uninitialized se_cmd
1523  *
1524  * @se_cmd: command descriptor to submit
1525  * @se_sess: associated se_sess for endpoint
1526  * @cdb: pointer to SCSI CDB
1527  * @sense: pointer to SCSI sense buffer
1528  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1529  * @data_length: fabric expected data transfer length
1530  * @task_addr: SAM task attribute
1531  * @data_dir: DMA data direction
1532  * @flags: flags for command submission from target_sc_flags_tables
1533  *
1534  * Task tags are supported if the caller has set @se_cmd->tag.
1535  *
1536  * Returns non zero to signal active I/O shutdown failure.  All other
1537  * setup exceptions will be returned as a SCSI CHECK_CONDITION response,
1538  * but still return zero here.
1539  *
1540  * This may only be called from process context, and also currently
1541  * assumes internal allocation of fabric payload buffer by target-core.
1542  *
1543  * It also assumes interal target core SGL memory allocation.
1544  */
1545 int target_submit_cmd(struct se_cmd *se_cmd, struct se_session *se_sess,
1546 		unsigned char *cdb, unsigned char *sense, u64 unpacked_lun,
1547 		u32 data_length, int task_attr, int data_dir, int flags)
1548 {
1549 	return target_submit_cmd_map_sgls(se_cmd, se_sess, cdb, sense,
1550 			unpacked_lun, data_length, task_attr, data_dir,
1551 			flags, NULL, 0, NULL, 0, NULL, 0);
1552 }
1553 EXPORT_SYMBOL(target_submit_cmd);
1554 
1555 static void target_complete_tmr_failure(struct work_struct *work)
1556 {
1557 	struct se_cmd *se_cmd = container_of(work, struct se_cmd, work);
1558 
1559 	se_cmd->se_tmr_req->response = TMR_LUN_DOES_NOT_EXIST;
1560 	se_cmd->se_tfo->queue_tm_rsp(se_cmd);
1561 
1562 	transport_cmd_check_stop_to_fabric(se_cmd);
1563 }
1564 
1565 /**
1566  * target_submit_tmr - lookup unpacked lun and submit uninitialized se_cmd
1567  *                     for TMR CDBs
1568  *
1569  * @se_cmd: command descriptor to submit
1570  * @se_sess: associated se_sess for endpoint
1571  * @sense: pointer to SCSI sense buffer
1572  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1573  * @fabric_context: fabric context for TMR req
1574  * @tm_type: Type of TM request
1575  * @gfp: gfp type for caller
1576  * @tag: referenced task tag for TMR_ABORT_TASK
1577  * @flags: submit cmd flags
1578  *
1579  * Callable from all contexts.
1580  **/
1581 
1582 int target_submit_tmr(struct se_cmd *se_cmd, struct se_session *se_sess,
1583 		unsigned char *sense, u64 unpacked_lun,
1584 		void *fabric_tmr_ptr, unsigned char tm_type,
1585 		gfp_t gfp, unsigned int tag, int flags)
1586 {
1587 	struct se_portal_group *se_tpg;
1588 	int ret;
1589 
1590 	se_tpg = se_sess->se_tpg;
1591 	BUG_ON(!se_tpg);
1592 
1593 	transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess,
1594 			      0, DMA_NONE, TCM_SIMPLE_TAG, sense);
1595 	/*
1596 	 * FIXME: Currently expect caller to handle se_cmd->se_tmr_req
1597 	 * allocation failure.
1598 	 */
1599 	ret = core_tmr_alloc_req(se_cmd, fabric_tmr_ptr, tm_type, gfp);
1600 	if (ret < 0)
1601 		return -ENOMEM;
1602 
1603 	if (tm_type == TMR_ABORT_TASK)
1604 		se_cmd->se_tmr_req->ref_task_tag = tag;
1605 
1606 	/* See target_submit_cmd for commentary */
1607 	ret = target_get_sess_cmd(se_cmd, flags & TARGET_SCF_ACK_KREF);
1608 	if (ret) {
1609 		core_tmr_release_req(se_cmd->se_tmr_req);
1610 		return ret;
1611 	}
1612 
1613 	ret = transport_lookup_tmr_lun(se_cmd, unpacked_lun);
1614 	if (ret) {
1615 		/*
1616 		 * For callback during failure handling, push this work off
1617 		 * to process context with TMR_LUN_DOES_NOT_EXIST status.
1618 		 */
1619 		INIT_WORK(&se_cmd->work, target_complete_tmr_failure);
1620 		schedule_work(&se_cmd->work);
1621 		return 0;
1622 	}
1623 	transport_generic_handle_tmr(se_cmd);
1624 	return 0;
1625 }
1626 EXPORT_SYMBOL(target_submit_tmr);
1627 
1628 /*
1629  * If the cmd is active, request it to be stopped and sleep until it
1630  * has completed.
1631  */
1632 bool target_stop_cmd(struct se_cmd *cmd, unsigned long *flags)
1633 	__releases(&cmd->t_state_lock)
1634 	__acquires(&cmd->t_state_lock)
1635 {
1636 	bool was_active = false;
1637 
1638 	if (cmd->transport_state & CMD_T_BUSY) {
1639 		cmd->transport_state |= CMD_T_REQUEST_STOP;
1640 		spin_unlock_irqrestore(&cmd->t_state_lock, *flags);
1641 
1642 		pr_debug("cmd %p waiting to complete\n", cmd);
1643 		wait_for_completion(&cmd->task_stop_comp);
1644 		pr_debug("cmd %p stopped successfully\n", cmd);
1645 
1646 		spin_lock_irqsave(&cmd->t_state_lock, *flags);
1647 		cmd->transport_state &= ~CMD_T_REQUEST_STOP;
1648 		cmd->transport_state &= ~CMD_T_BUSY;
1649 		was_active = true;
1650 	}
1651 
1652 	return was_active;
1653 }
1654 
1655 /*
1656  * Handle SAM-esque emulation for generic transport request failures.
1657  */
1658 void transport_generic_request_failure(struct se_cmd *cmd,
1659 		sense_reason_t sense_reason)
1660 {
1661 	int ret = 0;
1662 
1663 	pr_debug("-----[ Storage Engine Exception for cmd: %p ITT: 0x%08llx"
1664 		" CDB: 0x%02x\n", cmd, cmd->tag, cmd->t_task_cdb[0]);
1665 	pr_debug("-----[ i_state: %d t_state: %d sense_reason: %d\n",
1666 		cmd->se_tfo->get_cmd_state(cmd),
1667 		cmd->t_state, sense_reason);
1668 	pr_debug("-----[ CMD_T_ACTIVE: %d CMD_T_STOP: %d CMD_T_SENT: %d\n",
1669 		(cmd->transport_state & CMD_T_ACTIVE) != 0,
1670 		(cmd->transport_state & CMD_T_STOP) != 0,
1671 		(cmd->transport_state & CMD_T_SENT) != 0);
1672 
1673 	/*
1674 	 * For SAM Task Attribute emulation for failed struct se_cmd
1675 	 */
1676 	transport_complete_task_attr(cmd);
1677 	/*
1678 	 * Handle special case for COMPARE_AND_WRITE failure, where the
1679 	 * callback is expected to drop the per device ->caw_sem.
1680 	 */
1681 	if ((cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) &&
1682 	     cmd->transport_complete_callback)
1683 		cmd->transport_complete_callback(cmd, false);
1684 
1685 	switch (sense_reason) {
1686 	case TCM_NON_EXISTENT_LUN:
1687 	case TCM_UNSUPPORTED_SCSI_OPCODE:
1688 	case TCM_INVALID_CDB_FIELD:
1689 	case TCM_INVALID_PARAMETER_LIST:
1690 	case TCM_PARAMETER_LIST_LENGTH_ERROR:
1691 	case TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE:
1692 	case TCM_UNKNOWN_MODE_PAGE:
1693 	case TCM_WRITE_PROTECTED:
1694 	case TCM_ADDRESS_OUT_OF_RANGE:
1695 	case TCM_CHECK_CONDITION_ABORT_CMD:
1696 	case TCM_CHECK_CONDITION_UNIT_ATTENTION:
1697 	case TCM_CHECK_CONDITION_NOT_READY:
1698 	case TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED:
1699 	case TCM_LOGICAL_BLOCK_APP_TAG_CHECK_FAILED:
1700 	case TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED:
1701 		break;
1702 	case TCM_OUT_OF_RESOURCES:
1703 		sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
1704 		break;
1705 	case TCM_RESERVATION_CONFLICT:
1706 		/*
1707 		 * No SENSE Data payload for this case, set SCSI Status
1708 		 * and queue the response to $FABRIC_MOD.
1709 		 *
1710 		 * Uses linux/include/scsi/scsi.h SAM status codes defs
1711 		 */
1712 		cmd->scsi_status = SAM_STAT_RESERVATION_CONFLICT;
1713 		/*
1714 		 * For UA Interlock Code 11b, a RESERVATION CONFLICT will
1715 		 * establish a UNIT ATTENTION with PREVIOUS RESERVATION
1716 		 * CONFLICT STATUS.
1717 		 *
1718 		 * See spc4r17, section 7.4.6 Control Mode Page, Table 349
1719 		 */
1720 		if (cmd->se_sess &&
1721 		    cmd->se_dev->dev_attrib.emulate_ua_intlck_ctrl == 2) {
1722 			target_ua_allocate_lun(cmd->se_sess->se_node_acl,
1723 					       cmd->orig_fe_lun, 0x2C,
1724 					ASCQ_2CH_PREVIOUS_RESERVATION_CONFLICT_STATUS);
1725 		}
1726 		trace_target_cmd_complete(cmd);
1727 		ret = cmd->se_tfo->queue_status(cmd);
1728 		if (ret == -EAGAIN || ret == -ENOMEM)
1729 			goto queue_full;
1730 		goto check_stop;
1731 	default:
1732 		pr_err("Unknown transport error for CDB 0x%02x: %d\n",
1733 			cmd->t_task_cdb[0], sense_reason);
1734 		sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
1735 		break;
1736 	}
1737 
1738 	ret = transport_send_check_condition_and_sense(cmd, sense_reason, 0);
1739 	if (ret == -EAGAIN || ret == -ENOMEM)
1740 		goto queue_full;
1741 
1742 check_stop:
1743 	transport_lun_remove_cmd(cmd);
1744 	transport_cmd_check_stop_to_fabric(cmd);
1745 	return;
1746 
1747 queue_full:
1748 	cmd->t_state = TRANSPORT_COMPLETE_QF_OK;
1749 	transport_handle_queue_full(cmd, cmd->se_dev);
1750 }
1751 EXPORT_SYMBOL(transport_generic_request_failure);
1752 
1753 void __target_execute_cmd(struct se_cmd *cmd)
1754 {
1755 	sense_reason_t ret;
1756 
1757 	if (cmd->execute_cmd) {
1758 		ret = cmd->execute_cmd(cmd);
1759 		if (ret) {
1760 			spin_lock_irq(&cmd->t_state_lock);
1761 			cmd->transport_state &= ~(CMD_T_BUSY|CMD_T_SENT);
1762 			spin_unlock_irq(&cmd->t_state_lock);
1763 
1764 			transport_generic_request_failure(cmd, ret);
1765 		}
1766 	}
1767 }
1768 
1769 static int target_write_prot_action(struct se_cmd *cmd)
1770 {
1771 	u32 sectors;
1772 	/*
1773 	 * Perform WRITE_INSERT of PI using software emulation when backend
1774 	 * device has PI enabled, if the transport has not already generated
1775 	 * PI using hardware WRITE_INSERT offload.
1776 	 */
1777 	switch (cmd->prot_op) {
1778 	case TARGET_PROT_DOUT_INSERT:
1779 		if (!(cmd->se_sess->sup_prot_ops & TARGET_PROT_DOUT_INSERT))
1780 			sbc_dif_generate(cmd);
1781 		break;
1782 	case TARGET_PROT_DOUT_STRIP:
1783 		if (cmd->se_sess->sup_prot_ops & TARGET_PROT_DOUT_STRIP)
1784 			break;
1785 
1786 		sectors = cmd->data_length >> ilog2(cmd->se_dev->dev_attrib.block_size);
1787 		cmd->pi_err = sbc_dif_verify(cmd, cmd->t_task_lba,
1788 					     sectors, 0, cmd->t_prot_sg, 0);
1789 		if (unlikely(cmd->pi_err)) {
1790 			spin_lock_irq(&cmd->t_state_lock);
1791 			cmd->transport_state &= ~(CMD_T_BUSY|CMD_T_SENT);
1792 			spin_unlock_irq(&cmd->t_state_lock);
1793 			transport_generic_request_failure(cmd, cmd->pi_err);
1794 			return -1;
1795 		}
1796 		break;
1797 	default:
1798 		break;
1799 	}
1800 
1801 	return 0;
1802 }
1803 
1804 static bool target_handle_task_attr(struct se_cmd *cmd)
1805 {
1806 	struct se_device *dev = cmd->se_dev;
1807 
1808 	if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
1809 		return false;
1810 
1811 	/*
1812 	 * Check for the existence of HEAD_OF_QUEUE, and if true return 1
1813 	 * to allow the passed struct se_cmd list of tasks to the front of the list.
1814 	 */
1815 	switch (cmd->sam_task_attr) {
1816 	case TCM_HEAD_TAG:
1817 		pr_debug("Added HEAD_OF_QUEUE for CDB: 0x%02x\n",
1818 			 cmd->t_task_cdb[0]);
1819 		return false;
1820 	case TCM_ORDERED_TAG:
1821 		atomic_inc_mb(&dev->dev_ordered_sync);
1822 
1823 		pr_debug("Added ORDERED for CDB: 0x%02x to ordered list\n",
1824 			 cmd->t_task_cdb[0]);
1825 
1826 		/*
1827 		 * Execute an ORDERED command if no other older commands
1828 		 * exist that need to be completed first.
1829 		 */
1830 		if (!atomic_read(&dev->simple_cmds))
1831 			return false;
1832 		break;
1833 	default:
1834 		/*
1835 		 * For SIMPLE and UNTAGGED Task Attribute commands
1836 		 */
1837 		atomic_inc_mb(&dev->simple_cmds);
1838 		break;
1839 	}
1840 
1841 	if (atomic_read(&dev->dev_ordered_sync) == 0)
1842 		return false;
1843 
1844 	spin_lock(&dev->delayed_cmd_lock);
1845 	list_add_tail(&cmd->se_delayed_node, &dev->delayed_cmd_list);
1846 	spin_unlock(&dev->delayed_cmd_lock);
1847 
1848 	pr_debug("Added CDB: 0x%02x Task Attr: 0x%02x to delayed CMD listn",
1849 		cmd->t_task_cdb[0], cmd->sam_task_attr);
1850 	return true;
1851 }
1852 
1853 void target_execute_cmd(struct se_cmd *cmd)
1854 {
1855 	/*
1856 	 * If the received CDB has aleady been aborted stop processing it here.
1857 	 */
1858 	if (transport_check_aborted_status(cmd, 1))
1859 		return;
1860 
1861 	/*
1862 	 * Determine if frontend context caller is requesting the stopping of
1863 	 * this command for frontend exceptions.
1864 	 */
1865 	spin_lock_irq(&cmd->t_state_lock);
1866 	if (cmd->transport_state & CMD_T_STOP) {
1867 		pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08llx\n",
1868 			__func__, __LINE__, cmd->tag);
1869 
1870 		spin_unlock_irq(&cmd->t_state_lock);
1871 		complete_all(&cmd->t_transport_stop_comp);
1872 		return;
1873 	}
1874 
1875 	cmd->t_state = TRANSPORT_PROCESSING;
1876 	cmd->transport_state |= CMD_T_ACTIVE|CMD_T_BUSY|CMD_T_SENT;
1877 	spin_unlock_irq(&cmd->t_state_lock);
1878 
1879 	if (target_write_prot_action(cmd))
1880 		return;
1881 
1882 	if (target_handle_task_attr(cmd)) {
1883 		spin_lock_irq(&cmd->t_state_lock);
1884 		cmd->transport_state &= ~(CMD_T_BUSY | CMD_T_SENT);
1885 		spin_unlock_irq(&cmd->t_state_lock);
1886 		return;
1887 	}
1888 
1889 	__target_execute_cmd(cmd);
1890 }
1891 EXPORT_SYMBOL(target_execute_cmd);
1892 
1893 /*
1894  * Process all commands up to the last received ORDERED task attribute which
1895  * requires another blocking boundary
1896  */
1897 static void target_restart_delayed_cmds(struct se_device *dev)
1898 {
1899 	for (;;) {
1900 		struct se_cmd *cmd;
1901 
1902 		spin_lock(&dev->delayed_cmd_lock);
1903 		if (list_empty(&dev->delayed_cmd_list)) {
1904 			spin_unlock(&dev->delayed_cmd_lock);
1905 			break;
1906 		}
1907 
1908 		cmd = list_entry(dev->delayed_cmd_list.next,
1909 				 struct se_cmd, se_delayed_node);
1910 		list_del(&cmd->se_delayed_node);
1911 		spin_unlock(&dev->delayed_cmd_lock);
1912 
1913 		__target_execute_cmd(cmd);
1914 
1915 		if (cmd->sam_task_attr == TCM_ORDERED_TAG)
1916 			break;
1917 	}
1918 }
1919 
1920 /*
1921  * Called from I/O completion to determine which dormant/delayed
1922  * and ordered cmds need to have their tasks added to the execution queue.
1923  */
1924 static void transport_complete_task_attr(struct se_cmd *cmd)
1925 {
1926 	struct se_device *dev = cmd->se_dev;
1927 
1928 	if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
1929 		return;
1930 
1931 	if (cmd->sam_task_attr == TCM_SIMPLE_TAG) {
1932 		atomic_dec_mb(&dev->simple_cmds);
1933 		dev->dev_cur_ordered_id++;
1934 		pr_debug("Incremented dev->dev_cur_ordered_id: %u for SIMPLE\n",
1935 			 dev->dev_cur_ordered_id);
1936 	} else if (cmd->sam_task_attr == TCM_HEAD_TAG) {
1937 		dev->dev_cur_ordered_id++;
1938 		pr_debug("Incremented dev_cur_ordered_id: %u for HEAD_OF_QUEUE\n",
1939 			 dev->dev_cur_ordered_id);
1940 	} else if (cmd->sam_task_attr == TCM_ORDERED_TAG) {
1941 		atomic_dec_mb(&dev->dev_ordered_sync);
1942 
1943 		dev->dev_cur_ordered_id++;
1944 		pr_debug("Incremented dev_cur_ordered_id: %u for ORDERED\n",
1945 			 dev->dev_cur_ordered_id);
1946 	}
1947 
1948 	target_restart_delayed_cmds(dev);
1949 }
1950 
1951 static void transport_complete_qf(struct se_cmd *cmd)
1952 {
1953 	int ret = 0;
1954 
1955 	transport_complete_task_attr(cmd);
1956 
1957 	if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) {
1958 		trace_target_cmd_complete(cmd);
1959 		ret = cmd->se_tfo->queue_status(cmd);
1960 		goto out;
1961 	}
1962 
1963 	switch (cmd->data_direction) {
1964 	case DMA_FROM_DEVICE:
1965 		trace_target_cmd_complete(cmd);
1966 		ret = cmd->se_tfo->queue_data_in(cmd);
1967 		break;
1968 	case DMA_TO_DEVICE:
1969 		if (cmd->se_cmd_flags & SCF_BIDI) {
1970 			ret = cmd->se_tfo->queue_data_in(cmd);
1971 			break;
1972 		}
1973 		/* Fall through for DMA_TO_DEVICE */
1974 	case DMA_NONE:
1975 		trace_target_cmd_complete(cmd);
1976 		ret = cmd->se_tfo->queue_status(cmd);
1977 		break;
1978 	default:
1979 		break;
1980 	}
1981 
1982 out:
1983 	if (ret < 0) {
1984 		transport_handle_queue_full(cmd, cmd->se_dev);
1985 		return;
1986 	}
1987 	transport_lun_remove_cmd(cmd);
1988 	transport_cmd_check_stop_to_fabric(cmd);
1989 }
1990 
1991 static void transport_handle_queue_full(
1992 	struct se_cmd *cmd,
1993 	struct se_device *dev)
1994 {
1995 	spin_lock_irq(&dev->qf_cmd_lock);
1996 	list_add_tail(&cmd->se_qf_node, &cmd->se_dev->qf_cmd_list);
1997 	atomic_inc_mb(&dev->dev_qf_count);
1998 	spin_unlock_irq(&cmd->se_dev->qf_cmd_lock);
1999 
2000 	schedule_work(&cmd->se_dev->qf_work_queue);
2001 }
2002 
2003 static bool target_read_prot_action(struct se_cmd *cmd)
2004 {
2005 	switch (cmd->prot_op) {
2006 	case TARGET_PROT_DIN_STRIP:
2007 		if (!(cmd->se_sess->sup_prot_ops & TARGET_PROT_DIN_STRIP)) {
2008 			u32 sectors = cmd->data_length >>
2009 				  ilog2(cmd->se_dev->dev_attrib.block_size);
2010 
2011 			cmd->pi_err = sbc_dif_verify(cmd, cmd->t_task_lba,
2012 						     sectors, 0, cmd->t_prot_sg,
2013 						     0);
2014 			if (cmd->pi_err)
2015 				return true;
2016 		}
2017 		break;
2018 	case TARGET_PROT_DIN_INSERT:
2019 		if (cmd->se_sess->sup_prot_ops & TARGET_PROT_DIN_INSERT)
2020 			break;
2021 
2022 		sbc_dif_generate(cmd);
2023 		break;
2024 	default:
2025 		break;
2026 	}
2027 
2028 	return false;
2029 }
2030 
2031 static void target_complete_ok_work(struct work_struct *work)
2032 {
2033 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
2034 	int ret;
2035 
2036 	/*
2037 	 * Check if we need to move delayed/dormant tasks from cmds on the
2038 	 * delayed execution list after a HEAD_OF_QUEUE or ORDERED Task
2039 	 * Attribute.
2040 	 */
2041 	transport_complete_task_attr(cmd);
2042 
2043 	/*
2044 	 * Check to schedule QUEUE_FULL work, or execute an existing
2045 	 * cmd->transport_qf_callback()
2046 	 */
2047 	if (atomic_read(&cmd->se_dev->dev_qf_count) != 0)
2048 		schedule_work(&cmd->se_dev->qf_work_queue);
2049 
2050 	/*
2051 	 * Check if we need to send a sense buffer from
2052 	 * the struct se_cmd in question.
2053 	 */
2054 	if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) {
2055 		WARN_ON(!cmd->scsi_status);
2056 		ret = transport_send_check_condition_and_sense(
2057 					cmd, 0, 1);
2058 		if (ret == -EAGAIN || ret == -ENOMEM)
2059 			goto queue_full;
2060 
2061 		transport_lun_remove_cmd(cmd);
2062 		transport_cmd_check_stop_to_fabric(cmd);
2063 		return;
2064 	}
2065 	/*
2066 	 * Check for a callback, used by amongst other things
2067 	 * XDWRITE_READ_10 and COMPARE_AND_WRITE emulation.
2068 	 */
2069 	if (cmd->transport_complete_callback) {
2070 		sense_reason_t rc;
2071 
2072 		rc = cmd->transport_complete_callback(cmd, true);
2073 		if (!rc && !(cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE_POST)) {
2074 			if ((cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) &&
2075 			    !cmd->data_length)
2076 				goto queue_rsp;
2077 
2078 			return;
2079 		} else if (rc) {
2080 			ret = transport_send_check_condition_and_sense(cmd,
2081 						rc, 0);
2082 			if (ret == -EAGAIN || ret == -ENOMEM)
2083 				goto queue_full;
2084 
2085 			transport_lun_remove_cmd(cmd);
2086 			transport_cmd_check_stop_to_fabric(cmd);
2087 			return;
2088 		}
2089 	}
2090 
2091 queue_rsp:
2092 	switch (cmd->data_direction) {
2093 	case DMA_FROM_DEVICE:
2094 		atomic_long_add(cmd->data_length,
2095 				&cmd->se_lun->lun_stats.tx_data_octets);
2096 		/*
2097 		 * Perform READ_STRIP of PI using software emulation when
2098 		 * backend had PI enabled, if the transport will not be
2099 		 * performing hardware READ_STRIP offload.
2100 		 */
2101 		if (target_read_prot_action(cmd)) {
2102 			ret = transport_send_check_condition_and_sense(cmd,
2103 						cmd->pi_err, 0);
2104 			if (ret == -EAGAIN || ret == -ENOMEM)
2105 				goto queue_full;
2106 
2107 			transport_lun_remove_cmd(cmd);
2108 			transport_cmd_check_stop_to_fabric(cmd);
2109 			return;
2110 		}
2111 
2112 		trace_target_cmd_complete(cmd);
2113 		ret = cmd->se_tfo->queue_data_in(cmd);
2114 		if (ret == -EAGAIN || ret == -ENOMEM)
2115 			goto queue_full;
2116 		break;
2117 	case DMA_TO_DEVICE:
2118 		atomic_long_add(cmd->data_length,
2119 				&cmd->se_lun->lun_stats.rx_data_octets);
2120 		/*
2121 		 * Check if we need to send READ payload for BIDI-COMMAND
2122 		 */
2123 		if (cmd->se_cmd_flags & SCF_BIDI) {
2124 			atomic_long_add(cmd->data_length,
2125 					&cmd->se_lun->lun_stats.tx_data_octets);
2126 			ret = cmd->se_tfo->queue_data_in(cmd);
2127 			if (ret == -EAGAIN || ret == -ENOMEM)
2128 				goto queue_full;
2129 			break;
2130 		}
2131 		/* Fall through for DMA_TO_DEVICE */
2132 	case DMA_NONE:
2133 		trace_target_cmd_complete(cmd);
2134 		ret = cmd->se_tfo->queue_status(cmd);
2135 		if (ret == -EAGAIN || ret == -ENOMEM)
2136 			goto queue_full;
2137 		break;
2138 	default:
2139 		break;
2140 	}
2141 
2142 	transport_lun_remove_cmd(cmd);
2143 	transport_cmd_check_stop_to_fabric(cmd);
2144 	return;
2145 
2146 queue_full:
2147 	pr_debug("Handling complete_ok QUEUE_FULL: se_cmd: %p,"
2148 		" data_direction: %d\n", cmd, cmd->data_direction);
2149 	cmd->t_state = TRANSPORT_COMPLETE_QF_OK;
2150 	transport_handle_queue_full(cmd, cmd->se_dev);
2151 }
2152 
2153 static inline void transport_free_sgl(struct scatterlist *sgl, int nents)
2154 {
2155 	struct scatterlist *sg;
2156 	int count;
2157 
2158 	for_each_sg(sgl, sg, nents, count)
2159 		__free_page(sg_page(sg));
2160 
2161 	kfree(sgl);
2162 }
2163 
2164 static inline void transport_reset_sgl_orig(struct se_cmd *cmd)
2165 {
2166 	/*
2167 	 * Check for saved t_data_sg that may be used for COMPARE_AND_WRITE
2168 	 * emulation, and free + reset pointers if necessary..
2169 	 */
2170 	if (!cmd->t_data_sg_orig)
2171 		return;
2172 
2173 	kfree(cmd->t_data_sg);
2174 	cmd->t_data_sg = cmd->t_data_sg_orig;
2175 	cmd->t_data_sg_orig = NULL;
2176 	cmd->t_data_nents = cmd->t_data_nents_orig;
2177 	cmd->t_data_nents_orig = 0;
2178 }
2179 
2180 static inline void transport_free_pages(struct se_cmd *cmd)
2181 {
2182 	if (!(cmd->se_cmd_flags & SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC)) {
2183 		transport_free_sgl(cmd->t_prot_sg, cmd->t_prot_nents);
2184 		cmd->t_prot_sg = NULL;
2185 		cmd->t_prot_nents = 0;
2186 	}
2187 
2188 	if (cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) {
2189 		/*
2190 		 * Release special case READ buffer payload required for
2191 		 * SG_TO_MEM_NOALLOC to function with COMPARE_AND_WRITE
2192 		 */
2193 		if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) {
2194 			transport_free_sgl(cmd->t_bidi_data_sg,
2195 					   cmd->t_bidi_data_nents);
2196 			cmd->t_bidi_data_sg = NULL;
2197 			cmd->t_bidi_data_nents = 0;
2198 		}
2199 		transport_reset_sgl_orig(cmd);
2200 		return;
2201 	}
2202 	transport_reset_sgl_orig(cmd);
2203 
2204 	transport_free_sgl(cmd->t_data_sg, cmd->t_data_nents);
2205 	cmd->t_data_sg = NULL;
2206 	cmd->t_data_nents = 0;
2207 
2208 	transport_free_sgl(cmd->t_bidi_data_sg, cmd->t_bidi_data_nents);
2209 	cmd->t_bidi_data_sg = NULL;
2210 	cmd->t_bidi_data_nents = 0;
2211 }
2212 
2213 /**
2214  * transport_release_cmd - free a command
2215  * @cmd:       command to free
2216  *
2217  * This routine unconditionally frees a command, and reference counting
2218  * or list removal must be done in the caller.
2219  */
2220 static int transport_release_cmd(struct se_cmd *cmd)
2221 {
2222 	BUG_ON(!cmd->se_tfo);
2223 
2224 	if (cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
2225 		core_tmr_release_req(cmd->se_tmr_req);
2226 	if (cmd->t_task_cdb != cmd->__t_task_cdb)
2227 		kfree(cmd->t_task_cdb);
2228 	/*
2229 	 * If this cmd has been setup with target_get_sess_cmd(), drop
2230 	 * the kref and call ->release_cmd() in kref callback.
2231 	 */
2232 	return target_put_sess_cmd(cmd);
2233 }
2234 
2235 /**
2236  * transport_put_cmd - release a reference to a command
2237  * @cmd:       command to release
2238  *
2239  * This routine releases our reference to the command and frees it if possible.
2240  */
2241 static int transport_put_cmd(struct se_cmd *cmd)
2242 {
2243 	transport_free_pages(cmd);
2244 	return transport_release_cmd(cmd);
2245 }
2246 
2247 void *transport_kmap_data_sg(struct se_cmd *cmd)
2248 {
2249 	struct scatterlist *sg = cmd->t_data_sg;
2250 	struct page **pages;
2251 	int i;
2252 
2253 	/*
2254 	 * We need to take into account a possible offset here for fabrics like
2255 	 * tcm_loop who may be using a contig buffer from the SCSI midlayer for
2256 	 * control CDBs passed as SGLs via transport_generic_map_mem_to_cmd()
2257 	 */
2258 	if (!cmd->t_data_nents)
2259 		return NULL;
2260 
2261 	BUG_ON(!sg);
2262 	if (cmd->t_data_nents == 1)
2263 		return kmap(sg_page(sg)) + sg->offset;
2264 
2265 	/* >1 page. use vmap */
2266 	pages = kmalloc(sizeof(*pages) * cmd->t_data_nents, GFP_KERNEL);
2267 	if (!pages)
2268 		return NULL;
2269 
2270 	/* convert sg[] to pages[] */
2271 	for_each_sg(cmd->t_data_sg, sg, cmd->t_data_nents, i) {
2272 		pages[i] = sg_page(sg);
2273 	}
2274 
2275 	cmd->t_data_vmap = vmap(pages, cmd->t_data_nents,  VM_MAP, PAGE_KERNEL);
2276 	kfree(pages);
2277 	if (!cmd->t_data_vmap)
2278 		return NULL;
2279 
2280 	return cmd->t_data_vmap + cmd->t_data_sg[0].offset;
2281 }
2282 EXPORT_SYMBOL(transport_kmap_data_sg);
2283 
2284 void transport_kunmap_data_sg(struct se_cmd *cmd)
2285 {
2286 	if (!cmd->t_data_nents) {
2287 		return;
2288 	} else if (cmd->t_data_nents == 1) {
2289 		kunmap(sg_page(cmd->t_data_sg));
2290 		return;
2291 	}
2292 
2293 	vunmap(cmd->t_data_vmap);
2294 	cmd->t_data_vmap = NULL;
2295 }
2296 EXPORT_SYMBOL(transport_kunmap_data_sg);
2297 
2298 int
2299 target_alloc_sgl(struct scatterlist **sgl, unsigned int *nents, u32 length,
2300 		 bool zero_page)
2301 {
2302 	struct scatterlist *sg;
2303 	struct page *page;
2304 	gfp_t zero_flag = (zero_page) ? __GFP_ZERO : 0;
2305 	unsigned int nent;
2306 	int i = 0;
2307 
2308 	nent = DIV_ROUND_UP(length, PAGE_SIZE);
2309 	sg = kmalloc(sizeof(struct scatterlist) * nent, GFP_KERNEL);
2310 	if (!sg)
2311 		return -ENOMEM;
2312 
2313 	sg_init_table(sg, nent);
2314 
2315 	while (length) {
2316 		u32 page_len = min_t(u32, length, PAGE_SIZE);
2317 		page = alloc_page(GFP_KERNEL | zero_flag);
2318 		if (!page)
2319 			goto out;
2320 
2321 		sg_set_page(&sg[i], page, page_len, 0);
2322 		length -= page_len;
2323 		i++;
2324 	}
2325 	*sgl = sg;
2326 	*nents = nent;
2327 	return 0;
2328 
2329 out:
2330 	while (i > 0) {
2331 		i--;
2332 		__free_page(sg_page(&sg[i]));
2333 	}
2334 	kfree(sg);
2335 	return -ENOMEM;
2336 }
2337 
2338 /*
2339  * Allocate any required resources to execute the command.  For writes we
2340  * might not have the payload yet, so notify the fabric via a call to
2341  * ->write_pending instead. Otherwise place it on the execution queue.
2342  */
2343 sense_reason_t
2344 transport_generic_new_cmd(struct se_cmd *cmd)
2345 {
2346 	int ret = 0;
2347 	bool zero_flag = !(cmd->se_cmd_flags & SCF_SCSI_DATA_CDB);
2348 
2349 	if (cmd->prot_op != TARGET_PROT_NORMAL &&
2350 	    !(cmd->se_cmd_flags & SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC)) {
2351 		ret = target_alloc_sgl(&cmd->t_prot_sg, &cmd->t_prot_nents,
2352 				       cmd->prot_length, true);
2353 		if (ret < 0)
2354 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2355 	}
2356 
2357 	/*
2358 	 * Determine is the TCM fabric module has already allocated physical
2359 	 * memory, and is directly calling transport_generic_map_mem_to_cmd()
2360 	 * beforehand.
2361 	 */
2362 	if (!(cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) &&
2363 	    cmd->data_length) {
2364 
2365 		if ((cmd->se_cmd_flags & SCF_BIDI) ||
2366 		    (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE)) {
2367 			u32 bidi_length;
2368 
2369 			if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE)
2370 				bidi_length = cmd->t_task_nolb *
2371 					      cmd->se_dev->dev_attrib.block_size;
2372 			else
2373 				bidi_length = cmd->data_length;
2374 
2375 			ret = target_alloc_sgl(&cmd->t_bidi_data_sg,
2376 					       &cmd->t_bidi_data_nents,
2377 					       bidi_length, zero_flag);
2378 			if (ret < 0)
2379 				return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2380 		}
2381 
2382 		ret = target_alloc_sgl(&cmd->t_data_sg, &cmd->t_data_nents,
2383 				       cmd->data_length, zero_flag);
2384 		if (ret < 0)
2385 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2386 	} else if ((cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) &&
2387 		    cmd->data_length) {
2388 		/*
2389 		 * Special case for COMPARE_AND_WRITE with fabrics
2390 		 * using SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC.
2391 		 */
2392 		u32 caw_length = cmd->t_task_nolb *
2393 				 cmd->se_dev->dev_attrib.block_size;
2394 
2395 		ret = target_alloc_sgl(&cmd->t_bidi_data_sg,
2396 				       &cmd->t_bidi_data_nents,
2397 				       caw_length, zero_flag);
2398 		if (ret < 0)
2399 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2400 	}
2401 	/*
2402 	 * If this command is not a write we can execute it right here,
2403 	 * for write buffers we need to notify the fabric driver first
2404 	 * and let it call back once the write buffers are ready.
2405 	 */
2406 	target_add_to_state_list(cmd);
2407 	if (cmd->data_direction != DMA_TO_DEVICE || cmd->data_length == 0) {
2408 		target_execute_cmd(cmd);
2409 		return 0;
2410 	}
2411 	transport_cmd_check_stop(cmd, false, true);
2412 
2413 	ret = cmd->se_tfo->write_pending(cmd);
2414 	if (ret == -EAGAIN || ret == -ENOMEM)
2415 		goto queue_full;
2416 
2417 	/* fabric drivers should only return -EAGAIN or -ENOMEM as error */
2418 	WARN_ON(ret);
2419 
2420 	return (!ret) ? 0 : TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2421 
2422 queue_full:
2423 	pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n", cmd);
2424 	cmd->t_state = TRANSPORT_COMPLETE_QF_WP;
2425 	transport_handle_queue_full(cmd, cmd->se_dev);
2426 	return 0;
2427 }
2428 EXPORT_SYMBOL(transport_generic_new_cmd);
2429 
2430 static void transport_write_pending_qf(struct se_cmd *cmd)
2431 {
2432 	int ret;
2433 
2434 	ret = cmd->se_tfo->write_pending(cmd);
2435 	if (ret == -EAGAIN || ret == -ENOMEM) {
2436 		pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n",
2437 			 cmd);
2438 		transport_handle_queue_full(cmd, cmd->se_dev);
2439 	}
2440 }
2441 
2442 int transport_generic_free_cmd(struct se_cmd *cmd, int wait_for_tasks)
2443 {
2444 	unsigned long flags;
2445 	int ret = 0;
2446 
2447 	if (!(cmd->se_cmd_flags & SCF_SE_LUN_CMD)) {
2448 		if (wait_for_tasks && (cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
2449 			 transport_wait_for_tasks(cmd);
2450 
2451 		ret = transport_release_cmd(cmd);
2452 	} else {
2453 		if (wait_for_tasks)
2454 			transport_wait_for_tasks(cmd);
2455 		/*
2456 		 * Handle WRITE failure case where transport_generic_new_cmd()
2457 		 * has already added se_cmd to state_list, but fabric has
2458 		 * failed command before I/O submission.
2459 		 */
2460 		if (cmd->state_active) {
2461 			spin_lock_irqsave(&cmd->t_state_lock, flags);
2462 			target_remove_from_state_list(cmd);
2463 			spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2464 		}
2465 
2466 		if (cmd->se_lun)
2467 			transport_lun_remove_cmd(cmd);
2468 
2469 		ret = transport_put_cmd(cmd);
2470 	}
2471 	return ret;
2472 }
2473 EXPORT_SYMBOL(transport_generic_free_cmd);
2474 
2475 /* target_get_sess_cmd - Add command to active ->sess_cmd_list
2476  * @se_cmd:	command descriptor to add
2477  * @ack_kref:	Signal that fabric will perform an ack target_put_sess_cmd()
2478  */
2479 int target_get_sess_cmd(struct se_cmd *se_cmd, bool ack_kref)
2480 {
2481 	struct se_session *se_sess = se_cmd->se_sess;
2482 	unsigned long flags;
2483 	int ret = 0;
2484 
2485 	/*
2486 	 * Add a second kref if the fabric caller is expecting to handle
2487 	 * fabric acknowledgement that requires two target_put_sess_cmd()
2488 	 * invocations before se_cmd descriptor release.
2489 	 */
2490 	if (ack_kref)
2491 		kref_get(&se_cmd->cmd_kref);
2492 
2493 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2494 	if (se_sess->sess_tearing_down) {
2495 		ret = -ESHUTDOWN;
2496 		goto out;
2497 	}
2498 	list_add_tail(&se_cmd->se_cmd_list, &se_sess->sess_cmd_list);
2499 out:
2500 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2501 
2502 	if (ret && ack_kref)
2503 		target_put_sess_cmd(se_cmd);
2504 
2505 	return ret;
2506 }
2507 EXPORT_SYMBOL(target_get_sess_cmd);
2508 
2509 static void target_release_cmd_kref(struct kref *kref)
2510 		__releases(&se_cmd->se_sess->sess_cmd_lock)
2511 {
2512 	struct se_cmd *se_cmd = container_of(kref, struct se_cmd, cmd_kref);
2513 	struct se_session *se_sess = se_cmd->se_sess;
2514 
2515 	if (list_empty(&se_cmd->se_cmd_list)) {
2516 		spin_unlock(&se_sess->sess_cmd_lock);
2517 		se_cmd->se_tfo->release_cmd(se_cmd);
2518 		return;
2519 	}
2520 	if (se_sess->sess_tearing_down && se_cmd->cmd_wait_set) {
2521 		spin_unlock(&se_sess->sess_cmd_lock);
2522 		complete(&se_cmd->cmd_wait_comp);
2523 		return;
2524 	}
2525 	list_del(&se_cmd->se_cmd_list);
2526 	spin_unlock(&se_sess->sess_cmd_lock);
2527 
2528 	se_cmd->se_tfo->release_cmd(se_cmd);
2529 }
2530 
2531 /* target_put_sess_cmd - Check for active I/O shutdown via kref_put
2532  * @se_cmd:	command descriptor to drop
2533  */
2534 int target_put_sess_cmd(struct se_cmd *se_cmd)
2535 {
2536 	struct se_session *se_sess = se_cmd->se_sess;
2537 
2538 	if (!se_sess) {
2539 		se_cmd->se_tfo->release_cmd(se_cmd);
2540 		return 1;
2541 	}
2542 	return kref_put_spinlock_irqsave(&se_cmd->cmd_kref, target_release_cmd_kref,
2543 			&se_sess->sess_cmd_lock);
2544 }
2545 EXPORT_SYMBOL(target_put_sess_cmd);
2546 
2547 /* target_sess_cmd_list_set_waiting - Flag all commands in
2548  *         sess_cmd_list to complete cmd_wait_comp.  Set
2549  *         sess_tearing_down so no more commands are queued.
2550  * @se_sess:	session to flag
2551  */
2552 void target_sess_cmd_list_set_waiting(struct se_session *se_sess)
2553 {
2554 	struct se_cmd *se_cmd;
2555 	unsigned long flags;
2556 
2557 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2558 	if (se_sess->sess_tearing_down) {
2559 		spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2560 		return;
2561 	}
2562 	se_sess->sess_tearing_down = 1;
2563 	list_splice_init(&se_sess->sess_cmd_list, &se_sess->sess_wait_list);
2564 
2565 	list_for_each_entry(se_cmd, &se_sess->sess_wait_list, se_cmd_list)
2566 		se_cmd->cmd_wait_set = 1;
2567 
2568 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2569 }
2570 EXPORT_SYMBOL(target_sess_cmd_list_set_waiting);
2571 
2572 /* target_wait_for_sess_cmds - Wait for outstanding descriptors
2573  * @se_sess:    session to wait for active I/O
2574  */
2575 void target_wait_for_sess_cmds(struct se_session *se_sess)
2576 {
2577 	struct se_cmd *se_cmd, *tmp_cmd;
2578 	unsigned long flags;
2579 
2580 	list_for_each_entry_safe(se_cmd, tmp_cmd,
2581 				&se_sess->sess_wait_list, se_cmd_list) {
2582 		list_del(&se_cmd->se_cmd_list);
2583 
2584 		pr_debug("Waiting for se_cmd: %p t_state: %d, fabric state:"
2585 			" %d\n", se_cmd, se_cmd->t_state,
2586 			se_cmd->se_tfo->get_cmd_state(se_cmd));
2587 
2588 		wait_for_completion(&se_cmd->cmd_wait_comp);
2589 		pr_debug("After cmd_wait_comp: se_cmd: %p t_state: %d"
2590 			" fabric state: %d\n", se_cmd, se_cmd->t_state,
2591 			se_cmd->se_tfo->get_cmd_state(se_cmd));
2592 
2593 		se_cmd->se_tfo->release_cmd(se_cmd);
2594 	}
2595 
2596 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2597 	WARN_ON(!list_empty(&se_sess->sess_cmd_list));
2598 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2599 
2600 }
2601 EXPORT_SYMBOL(target_wait_for_sess_cmds);
2602 
2603 void transport_clear_lun_ref(struct se_lun *lun)
2604 {
2605 	percpu_ref_kill(&lun->lun_ref);
2606 	wait_for_completion(&lun->lun_ref_comp);
2607 }
2608 
2609 /**
2610  * transport_wait_for_tasks - wait for completion to occur
2611  * @cmd:	command to wait
2612  *
2613  * Called from frontend fabric context to wait for storage engine
2614  * to pause and/or release frontend generated struct se_cmd.
2615  */
2616 bool transport_wait_for_tasks(struct se_cmd *cmd)
2617 {
2618 	unsigned long flags;
2619 
2620 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2621 	if (!(cmd->se_cmd_flags & SCF_SE_LUN_CMD) &&
2622 	    !(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)) {
2623 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2624 		return false;
2625 	}
2626 
2627 	if (!(cmd->se_cmd_flags & SCF_SUPPORTED_SAM_OPCODE) &&
2628 	    !(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)) {
2629 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2630 		return false;
2631 	}
2632 
2633 	if (!(cmd->transport_state & CMD_T_ACTIVE)) {
2634 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2635 		return false;
2636 	}
2637 
2638 	cmd->transport_state |= CMD_T_STOP;
2639 
2640 	pr_debug("wait_for_tasks: Stopping %p ITT: 0x%08llx i_state: %d, t_state: %d, CMD_T_STOP\n",
2641 		cmd, cmd->tag, cmd->se_tfo->get_cmd_state(cmd), cmd->t_state);
2642 
2643 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2644 
2645 	wait_for_completion(&cmd->t_transport_stop_comp);
2646 
2647 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2648 	cmd->transport_state &= ~(CMD_T_ACTIVE | CMD_T_STOP);
2649 
2650 	pr_debug("wait_for_tasks: Stopped wait_for_completion(&cmd->t_transport_stop_comp) for ITT: 0x%08llx\n",
2651 		cmd->tag);
2652 
2653 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2654 
2655 	return true;
2656 }
2657 EXPORT_SYMBOL(transport_wait_for_tasks);
2658 
2659 struct sense_info {
2660 	u8 key;
2661 	u8 asc;
2662 	u8 ascq;
2663 	bool add_sector_info;
2664 };
2665 
2666 static const struct sense_info sense_info_table[] = {
2667 	[TCM_NO_SENSE] = {
2668 		.key = NOT_READY
2669 	},
2670 	[TCM_NON_EXISTENT_LUN] = {
2671 		.key = ILLEGAL_REQUEST,
2672 		.asc = 0x25 /* LOGICAL UNIT NOT SUPPORTED */
2673 	},
2674 	[TCM_UNSUPPORTED_SCSI_OPCODE] = {
2675 		.key = ILLEGAL_REQUEST,
2676 		.asc = 0x20, /* INVALID COMMAND OPERATION CODE */
2677 	},
2678 	[TCM_SECTOR_COUNT_TOO_MANY] = {
2679 		.key = ILLEGAL_REQUEST,
2680 		.asc = 0x20, /* INVALID COMMAND OPERATION CODE */
2681 	},
2682 	[TCM_UNKNOWN_MODE_PAGE] = {
2683 		.key = ILLEGAL_REQUEST,
2684 		.asc = 0x24, /* INVALID FIELD IN CDB */
2685 	},
2686 	[TCM_CHECK_CONDITION_ABORT_CMD] = {
2687 		.key = ABORTED_COMMAND,
2688 		.asc = 0x29, /* BUS DEVICE RESET FUNCTION OCCURRED */
2689 		.ascq = 0x03,
2690 	},
2691 	[TCM_INCORRECT_AMOUNT_OF_DATA] = {
2692 		.key = ABORTED_COMMAND,
2693 		.asc = 0x0c, /* WRITE ERROR */
2694 		.ascq = 0x0d, /* NOT ENOUGH UNSOLICITED DATA */
2695 	},
2696 	[TCM_INVALID_CDB_FIELD] = {
2697 		.key = ILLEGAL_REQUEST,
2698 		.asc = 0x24, /* INVALID FIELD IN CDB */
2699 	},
2700 	[TCM_INVALID_PARAMETER_LIST] = {
2701 		.key = ILLEGAL_REQUEST,
2702 		.asc = 0x26, /* INVALID FIELD IN PARAMETER LIST */
2703 	},
2704 	[TCM_PARAMETER_LIST_LENGTH_ERROR] = {
2705 		.key = ILLEGAL_REQUEST,
2706 		.asc = 0x1a, /* PARAMETER LIST LENGTH ERROR */
2707 	},
2708 	[TCM_UNEXPECTED_UNSOLICITED_DATA] = {
2709 		.key = ILLEGAL_REQUEST,
2710 		.asc = 0x0c, /* WRITE ERROR */
2711 		.ascq = 0x0c, /* UNEXPECTED_UNSOLICITED_DATA */
2712 	},
2713 	[TCM_SERVICE_CRC_ERROR] = {
2714 		.key = ABORTED_COMMAND,
2715 		.asc = 0x47, /* PROTOCOL SERVICE CRC ERROR */
2716 		.ascq = 0x05, /* N/A */
2717 	},
2718 	[TCM_SNACK_REJECTED] = {
2719 		.key = ABORTED_COMMAND,
2720 		.asc = 0x11, /* READ ERROR */
2721 		.ascq = 0x13, /* FAILED RETRANSMISSION REQUEST */
2722 	},
2723 	[TCM_WRITE_PROTECTED] = {
2724 		.key = DATA_PROTECT,
2725 		.asc = 0x27, /* WRITE PROTECTED */
2726 	},
2727 	[TCM_ADDRESS_OUT_OF_RANGE] = {
2728 		.key = ILLEGAL_REQUEST,
2729 		.asc = 0x21, /* LOGICAL BLOCK ADDRESS OUT OF RANGE */
2730 	},
2731 	[TCM_CHECK_CONDITION_UNIT_ATTENTION] = {
2732 		.key = UNIT_ATTENTION,
2733 	},
2734 	[TCM_CHECK_CONDITION_NOT_READY] = {
2735 		.key = NOT_READY,
2736 	},
2737 	[TCM_MISCOMPARE_VERIFY] = {
2738 		.key = MISCOMPARE,
2739 		.asc = 0x1d, /* MISCOMPARE DURING VERIFY OPERATION */
2740 		.ascq = 0x00,
2741 	},
2742 	[TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED] = {
2743 		.key = ABORTED_COMMAND,
2744 		.asc = 0x10,
2745 		.ascq = 0x01, /* LOGICAL BLOCK GUARD CHECK FAILED */
2746 		.add_sector_info = true,
2747 	},
2748 	[TCM_LOGICAL_BLOCK_APP_TAG_CHECK_FAILED] = {
2749 		.key = ABORTED_COMMAND,
2750 		.asc = 0x10,
2751 		.ascq = 0x02, /* LOGICAL BLOCK APPLICATION TAG CHECK FAILED */
2752 		.add_sector_info = true,
2753 	},
2754 	[TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED] = {
2755 		.key = ABORTED_COMMAND,
2756 		.asc = 0x10,
2757 		.ascq = 0x03, /* LOGICAL BLOCK REFERENCE TAG CHECK FAILED */
2758 		.add_sector_info = true,
2759 	},
2760 	[TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE] = {
2761 		/*
2762 		 * Returning ILLEGAL REQUEST would cause immediate IO errors on
2763 		 * Solaris initiators.  Returning NOT READY instead means the
2764 		 * operations will be retried a finite number of times and we
2765 		 * can survive intermittent errors.
2766 		 */
2767 		.key = NOT_READY,
2768 		.asc = 0x08, /* LOGICAL UNIT COMMUNICATION FAILURE */
2769 	},
2770 };
2771 
2772 static int translate_sense_reason(struct se_cmd *cmd, sense_reason_t reason)
2773 {
2774 	const struct sense_info *si;
2775 	u8 *buffer = cmd->sense_buffer;
2776 	int r = (__force int)reason;
2777 	u8 asc, ascq;
2778 	bool desc_format = target_sense_desc_format(cmd->se_dev);
2779 
2780 	if (r < ARRAY_SIZE(sense_info_table) && sense_info_table[r].key)
2781 		si = &sense_info_table[r];
2782 	else
2783 		si = &sense_info_table[(__force int)
2784 				       TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE];
2785 
2786 	if (reason == TCM_CHECK_CONDITION_UNIT_ATTENTION) {
2787 		core_scsi3_ua_for_check_condition(cmd, &asc, &ascq);
2788 		WARN_ON_ONCE(asc == 0);
2789 	} else if (si->asc == 0) {
2790 		WARN_ON_ONCE(cmd->scsi_asc == 0);
2791 		asc = cmd->scsi_asc;
2792 		ascq = cmd->scsi_ascq;
2793 	} else {
2794 		asc = si->asc;
2795 		ascq = si->ascq;
2796 	}
2797 
2798 	scsi_build_sense_buffer(desc_format, buffer, si->key, asc, ascq);
2799 	if (si->add_sector_info)
2800 		return scsi_set_sense_information(buffer,
2801 						  cmd->scsi_sense_length,
2802 						  cmd->bad_sector);
2803 
2804 	return 0;
2805 }
2806 
2807 int
2808 transport_send_check_condition_and_sense(struct se_cmd *cmd,
2809 		sense_reason_t reason, int from_transport)
2810 {
2811 	unsigned long flags;
2812 
2813 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2814 	if (cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION) {
2815 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2816 		return 0;
2817 	}
2818 	cmd->se_cmd_flags |= SCF_SENT_CHECK_CONDITION;
2819 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2820 
2821 	if (!from_transport) {
2822 		int rc;
2823 
2824 		cmd->se_cmd_flags |= SCF_EMULATED_TASK_SENSE;
2825 		cmd->scsi_status = SAM_STAT_CHECK_CONDITION;
2826 		cmd->scsi_sense_length  = TRANSPORT_SENSE_BUFFER;
2827 		rc = translate_sense_reason(cmd, reason);
2828 		if (rc)
2829 			return rc;
2830 	}
2831 
2832 	trace_target_cmd_complete(cmd);
2833 	return cmd->se_tfo->queue_status(cmd);
2834 }
2835 EXPORT_SYMBOL(transport_send_check_condition_and_sense);
2836 
2837 int transport_check_aborted_status(struct se_cmd *cmd, int send_status)
2838 {
2839 	if (!(cmd->transport_state & CMD_T_ABORTED))
2840 		return 0;
2841 
2842 	/*
2843 	 * If cmd has been aborted but either no status is to be sent or it has
2844 	 * already been sent, just return
2845 	 */
2846 	if (!send_status || !(cmd->se_cmd_flags & SCF_SEND_DELAYED_TAS))
2847 		return 1;
2848 
2849 	pr_debug("Sending delayed SAM_STAT_TASK_ABORTED status for CDB: 0x%02x ITT: 0x%08llx\n",
2850 		 cmd->t_task_cdb[0], cmd->tag);
2851 
2852 	cmd->se_cmd_flags &= ~SCF_SEND_DELAYED_TAS;
2853 	cmd->scsi_status = SAM_STAT_TASK_ABORTED;
2854 	trace_target_cmd_complete(cmd);
2855 	cmd->se_tfo->queue_status(cmd);
2856 
2857 	return 1;
2858 }
2859 EXPORT_SYMBOL(transport_check_aborted_status);
2860 
2861 void transport_send_task_abort(struct se_cmd *cmd)
2862 {
2863 	unsigned long flags;
2864 
2865 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2866 	if (cmd->se_cmd_flags & (SCF_SENT_CHECK_CONDITION)) {
2867 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2868 		return;
2869 	}
2870 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2871 
2872 	/*
2873 	 * If there are still expected incoming fabric WRITEs, we wait
2874 	 * until until they have completed before sending a TASK_ABORTED
2875 	 * response.  This response with TASK_ABORTED status will be
2876 	 * queued back to fabric module by transport_check_aborted_status().
2877 	 */
2878 	if (cmd->data_direction == DMA_TO_DEVICE) {
2879 		if (cmd->se_tfo->write_pending_status(cmd) != 0) {
2880 			cmd->transport_state |= CMD_T_ABORTED;
2881 			cmd->se_cmd_flags |= SCF_SEND_DELAYED_TAS;
2882 			return;
2883 		}
2884 	}
2885 	cmd->scsi_status = SAM_STAT_TASK_ABORTED;
2886 
2887 	transport_lun_remove_cmd(cmd);
2888 
2889 	pr_debug("Setting SAM_STAT_TASK_ABORTED status for CDB: 0x%02x, ITT: 0x%08llx\n",
2890 		 cmd->t_task_cdb[0], cmd->tag);
2891 
2892 	trace_target_cmd_complete(cmd);
2893 	cmd->se_tfo->queue_status(cmd);
2894 }
2895 
2896 static void target_tmr_work(struct work_struct *work)
2897 {
2898 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
2899 	struct se_device *dev = cmd->se_dev;
2900 	struct se_tmr_req *tmr = cmd->se_tmr_req;
2901 	int ret;
2902 
2903 	switch (tmr->function) {
2904 	case TMR_ABORT_TASK:
2905 		core_tmr_abort_task(dev, tmr, cmd->se_sess);
2906 		break;
2907 	case TMR_ABORT_TASK_SET:
2908 	case TMR_CLEAR_ACA:
2909 	case TMR_CLEAR_TASK_SET:
2910 		tmr->response = TMR_TASK_MGMT_FUNCTION_NOT_SUPPORTED;
2911 		break;
2912 	case TMR_LUN_RESET:
2913 		ret = core_tmr_lun_reset(dev, tmr, NULL, NULL);
2914 		tmr->response = (!ret) ? TMR_FUNCTION_COMPLETE :
2915 					 TMR_FUNCTION_REJECTED;
2916 		if (tmr->response == TMR_FUNCTION_COMPLETE) {
2917 			target_ua_allocate_lun(cmd->se_sess->se_node_acl,
2918 					       cmd->orig_fe_lun, 0x29,
2919 					       ASCQ_29H_BUS_DEVICE_RESET_FUNCTION_OCCURRED);
2920 		}
2921 		break;
2922 	case TMR_TARGET_WARM_RESET:
2923 		tmr->response = TMR_FUNCTION_REJECTED;
2924 		break;
2925 	case TMR_TARGET_COLD_RESET:
2926 		tmr->response = TMR_FUNCTION_REJECTED;
2927 		break;
2928 	default:
2929 		pr_err("Uknown TMR function: 0x%02x.\n",
2930 				tmr->function);
2931 		tmr->response = TMR_FUNCTION_REJECTED;
2932 		break;
2933 	}
2934 
2935 	cmd->t_state = TRANSPORT_ISTATE_PROCESSING;
2936 	cmd->se_tfo->queue_tm_rsp(cmd);
2937 
2938 	transport_cmd_check_stop_to_fabric(cmd);
2939 }
2940 
2941 int transport_generic_handle_tmr(
2942 	struct se_cmd *cmd)
2943 {
2944 	unsigned long flags;
2945 
2946 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2947 	cmd->transport_state |= CMD_T_ACTIVE;
2948 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2949 
2950 	INIT_WORK(&cmd->work, target_tmr_work);
2951 	queue_work(cmd->se_dev->tmr_wq, &cmd->work);
2952 	return 0;
2953 }
2954 EXPORT_SYMBOL(transport_generic_handle_tmr);
2955 
2956 bool
2957 target_check_wce(struct se_device *dev)
2958 {
2959 	bool wce = false;
2960 
2961 	if (dev->transport->get_write_cache)
2962 		wce = dev->transport->get_write_cache(dev);
2963 	else if (dev->dev_attrib.emulate_write_cache > 0)
2964 		wce = true;
2965 
2966 	return wce;
2967 }
2968 
2969 bool
2970 target_check_fua(struct se_device *dev)
2971 {
2972 	return target_check_wce(dev) && dev->dev_attrib.emulate_fua_write > 0;
2973 }
2974