xref: /linux/drivers/target/target_core_transport.c (revision 9da8320bb97768e35f2e64fa7642015271d672eb)
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, post_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, &post_ret);
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 		bool caw = (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE);
2072 		bool zero_dl = !(cmd->data_length);
2073 		int post_ret = 0;
2074 
2075 		rc = cmd->transport_complete_callback(cmd, true, &post_ret);
2076 		if (!rc && !post_ret) {
2077 			if (caw && zero_dl)
2078 				goto queue_rsp;
2079 
2080 			return;
2081 		} else if (rc) {
2082 			ret = transport_send_check_condition_and_sense(cmd,
2083 						rc, 0);
2084 			if (ret == -EAGAIN || ret == -ENOMEM)
2085 				goto queue_full;
2086 
2087 			transport_lun_remove_cmd(cmd);
2088 			transport_cmd_check_stop_to_fabric(cmd);
2089 			return;
2090 		}
2091 	}
2092 
2093 queue_rsp:
2094 	switch (cmd->data_direction) {
2095 	case DMA_FROM_DEVICE:
2096 		atomic_long_add(cmd->data_length,
2097 				&cmd->se_lun->lun_stats.tx_data_octets);
2098 		/*
2099 		 * Perform READ_STRIP of PI using software emulation when
2100 		 * backend had PI enabled, if the transport will not be
2101 		 * performing hardware READ_STRIP offload.
2102 		 */
2103 		if (target_read_prot_action(cmd)) {
2104 			ret = transport_send_check_condition_and_sense(cmd,
2105 						cmd->pi_err, 0);
2106 			if (ret == -EAGAIN || ret == -ENOMEM)
2107 				goto queue_full;
2108 
2109 			transport_lun_remove_cmd(cmd);
2110 			transport_cmd_check_stop_to_fabric(cmd);
2111 			return;
2112 		}
2113 
2114 		trace_target_cmd_complete(cmd);
2115 		ret = cmd->se_tfo->queue_data_in(cmd);
2116 		if (ret == -EAGAIN || ret == -ENOMEM)
2117 			goto queue_full;
2118 		break;
2119 	case DMA_TO_DEVICE:
2120 		atomic_long_add(cmd->data_length,
2121 				&cmd->se_lun->lun_stats.rx_data_octets);
2122 		/*
2123 		 * Check if we need to send READ payload for BIDI-COMMAND
2124 		 */
2125 		if (cmd->se_cmd_flags & SCF_BIDI) {
2126 			atomic_long_add(cmd->data_length,
2127 					&cmd->se_lun->lun_stats.tx_data_octets);
2128 			ret = cmd->se_tfo->queue_data_in(cmd);
2129 			if (ret == -EAGAIN || ret == -ENOMEM)
2130 				goto queue_full;
2131 			break;
2132 		}
2133 		/* Fall through for DMA_TO_DEVICE */
2134 	case DMA_NONE:
2135 		trace_target_cmd_complete(cmd);
2136 		ret = cmd->se_tfo->queue_status(cmd);
2137 		if (ret == -EAGAIN || ret == -ENOMEM)
2138 			goto queue_full;
2139 		break;
2140 	default:
2141 		break;
2142 	}
2143 
2144 	transport_lun_remove_cmd(cmd);
2145 	transport_cmd_check_stop_to_fabric(cmd);
2146 	return;
2147 
2148 queue_full:
2149 	pr_debug("Handling complete_ok QUEUE_FULL: se_cmd: %p,"
2150 		" data_direction: %d\n", cmd, cmd->data_direction);
2151 	cmd->t_state = TRANSPORT_COMPLETE_QF_OK;
2152 	transport_handle_queue_full(cmd, cmd->se_dev);
2153 }
2154 
2155 static inline void transport_free_sgl(struct scatterlist *sgl, int nents)
2156 {
2157 	struct scatterlist *sg;
2158 	int count;
2159 
2160 	for_each_sg(sgl, sg, nents, count)
2161 		__free_page(sg_page(sg));
2162 
2163 	kfree(sgl);
2164 }
2165 
2166 static inline void transport_reset_sgl_orig(struct se_cmd *cmd)
2167 {
2168 	/*
2169 	 * Check for saved t_data_sg that may be used for COMPARE_AND_WRITE
2170 	 * emulation, and free + reset pointers if necessary..
2171 	 */
2172 	if (!cmd->t_data_sg_orig)
2173 		return;
2174 
2175 	kfree(cmd->t_data_sg);
2176 	cmd->t_data_sg = cmd->t_data_sg_orig;
2177 	cmd->t_data_sg_orig = NULL;
2178 	cmd->t_data_nents = cmd->t_data_nents_orig;
2179 	cmd->t_data_nents_orig = 0;
2180 }
2181 
2182 static inline void transport_free_pages(struct se_cmd *cmd)
2183 {
2184 	if (!(cmd->se_cmd_flags & SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC)) {
2185 		transport_free_sgl(cmd->t_prot_sg, cmd->t_prot_nents);
2186 		cmd->t_prot_sg = NULL;
2187 		cmd->t_prot_nents = 0;
2188 	}
2189 
2190 	if (cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) {
2191 		/*
2192 		 * Release special case READ buffer payload required for
2193 		 * SG_TO_MEM_NOALLOC to function with COMPARE_AND_WRITE
2194 		 */
2195 		if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) {
2196 			transport_free_sgl(cmd->t_bidi_data_sg,
2197 					   cmd->t_bidi_data_nents);
2198 			cmd->t_bidi_data_sg = NULL;
2199 			cmd->t_bidi_data_nents = 0;
2200 		}
2201 		transport_reset_sgl_orig(cmd);
2202 		return;
2203 	}
2204 	transport_reset_sgl_orig(cmd);
2205 
2206 	transport_free_sgl(cmd->t_data_sg, cmd->t_data_nents);
2207 	cmd->t_data_sg = NULL;
2208 	cmd->t_data_nents = 0;
2209 
2210 	transport_free_sgl(cmd->t_bidi_data_sg, cmd->t_bidi_data_nents);
2211 	cmd->t_bidi_data_sg = NULL;
2212 	cmd->t_bidi_data_nents = 0;
2213 }
2214 
2215 /**
2216  * transport_release_cmd - free a command
2217  * @cmd:       command to free
2218  *
2219  * This routine unconditionally frees a command, and reference counting
2220  * or list removal must be done in the caller.
2221  */
2222 static int transport_release_cmd(struct se_cmd *cmd)
2223 {
2224 	BUG_ON(!cmd->se_tfo);
2225 
2226 	if (cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
2227 		core_tmr_release_req(cmd->se_tmr_req);
2228 	if (cmd->t_task_cdb != cmd->__t_task_cdb)
2229 		kfree(cmd->t_task_cdb);
2230 	/*
2231 	 * If this cmd has been setup with target_get_sess_cmd(), drop
2232 	 * the kref and call ->release_cmd() in kref callback.
2233 	 */
2234 	return target_put_sess_cmd(cmd);
2235 }
2236 
2237 /**
2238  * transport_put_cmd - release a reference to a command
2239  * @cmd:       command to release
2240  *
2241  * This routine releases our reference to the command and frees it if possible.
2242  */
2243 static int transport_put_cmd(struct se_cmd *cmd)
2244 {
2245 	transport_free_pages(cmd);
2246 	return transport_release_cmd(cmd);
2247 }
2248 
2249 void *transport_kmap_data_sg(struct se_cmd *cmd)
2250 {
2251 	struct scatterlist *sg = cmd->t_data_sg;
2252 	struct page **pages;
2253 	int i;
2254 
2255 	/*
2256 	 * We need to take into account a possible offset here for fabrics like
2257 	 * tcm_loop who may be using a contig buffer from the SCSI midlayer for
2258 	 * control CDBs passed as SGLs via transport_generic_map_mem_to_cmd()
2259 	 */
2260 	if (!cmd->t_data_nents)
2261 		return NULL;
2262 
2263 	BUG_ON(!sg);
2264 	if (cmd->t_data_nents == 1)
2265 		return kmap(sg_page(sg)) + sg->offset;
2266 
2267 	/* >1 page. use vmap */
2268 	pages = kmalloc(sizeof(*pages) * cmd->t_data_nents, GFP_KERNEL);
2269 	if (!pages)
2270 		return NULL;
2271 
2272 	/* convert sg[] to pages[] */
2273 	for_each_sg(cmd->t_data_sg, sg, cmd->t_data_nents, i) {
2274 		pages[i] = sg_page(sg);
2275 	}
2276 
2277 	cmd->t_data_vmap = vmap(pages, cmd->t_data_nents,  VM_MAP, PAGE_KERNEL);
2278 	kfree(pages);
2279 	if (!cmd->t_data_vmap)
2280 		return NULL;
2281 
2282 	return cmd->t_data_vmap + cmd->t_data_sg[0].offset;
2283 }
2284 EXPORT_SYMBOL(transport_kmap_data_sg);
2285 
2286 void transport_kunmap_data_sg(struct se_cmd *cmd)
2287 {
2288 	if (!cmd->t_data_nents) {
2289 		return;
2290 	} else if (cmd->t_data_nents == 1) {
2291 		kunmap(sg_page(cmd->t_data_sg));
2292 		return;
2293 	}
2294 
2295 	vunmap(cmd->t_data_vmap);
2296 	cmd->t_data_vmap = NULL;
2297 }
2298 EXPORT_SYMBOL(transport_kunmap_data_sg);
2299 
2300 int
2301 target_alloc_sgl(struct scatterlist **sgl, unsigned int *nents, u32 length,
2302 		 bool zero_page)
2303 {
2304 	struct scatterlist *sg;
2305 	struct page *page;
2306 	gfp_t zero_flag = (zero_page) ? __GFP_ZERO : 0;
2307 	unsigned int nent;
2308 	int i = 0;
2309 
2310 	nent = DIV_ROUND_UP(length, PAGE_SIZE);
2311 	sg = kmalloc(sizeof(struct scatterlist) * nent, GFP_KERNEL);
2312 	if (!sg)
2313 		return -ENOMEM;
2314 
2315 	sg_init_table(sg, nent);
2316 
2317 	while (length) {
2318 		u32 page_len = min_t(u32, length, PAGE_SIZE);
2319 		page = alloc_page(GFP_KERNEL | zero_flag);
2320 		if (!page)
2321 			goto out;
2322 
2323 		sg_set_page(&sg[i], page, page_len, 0);
2324 		length -= page_len;
2325 		i++;
2326 	}
2327 	*sgl = sg;
2328 	*nents = nent;
2329 	return 0;
2330 
2331 out:
2332 	while (i > 0) {
2333 		i--;
2334 		__free_page(sg_page(&sg[i]));
2335 	}
2336 	kfree(sg);
2337 	return -ENOMEM;
2338 }
2339 
2340 /*
2341  * Allocate any required resources to execute the command.  For writes we
2342  * might not have the payload yet, so notify the fabric via a call to
2343  * ->write_pending instead. Otherwise place it on the execution queue.
2344  */
2345 sense_reason_t
2346 transport_generic_new_cmd(struct se_cmd *cmd)
2347 {
2348 	int ret = 0;
2349 	bool zero_flag = !(cmd->se_cmd_flags & SCF_SCSI_DATA_CDB);
2350 
2351 	if (cmd->prot_op != TARGET_PROT_NORMAL &&
2352 	    !(cmd->se_cmd_flags & SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC)) {
2353 		ret = target_alloc_sgl(&cmd->t_prot_sg, &cmd->t_prot_nents,
2354 				       cmd->prot_length, true);
2355 		if (ret < 0)
2356 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2357 	}
2358 
2359 	/*
2360 	 * Determine is the TCM fabric module has already allocated physical
2361 	 * memory, and is directly calling transport_generic_map_mem_to_cmd()
2362 	 * beforehand.
2363 	 */
2364 	if (!(cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) &&
2365 	    cmd->data_length) {
2366 
2367 		if ((cmd->se_cmd_flags & SCF_BIDI) ||
2368 		    (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE)) {
2369 			u32 bidi_length;
2370 
2371 			if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE)
2372 				bidi_length = cmd->t_task_nolb *
2373 					      cmd->se_dev->dev_attrib.block_size;
2374 			else
2375 				bidi_length = cmd->data_length;
2376 
2377 			ret = target_alloc_sgl(&cmd->t_bidi_data_sg,
2378 					       &cmd->t_bidi_data_nents,
2379 					       bidi_length, zero_flag);
2380 			if (ret < 0)
2381 				return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2382 		}
2383 
2384 		ret = target_alloc_sgl(&cmd->t_data_sg, &cmd->t_data_nents,
2385 				       cmd->data_length, zero_flag);
2386 		if (ret < 0)
2387 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2388 	} else if ((cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) &&
2389 		    cmd->data_length) {
2390 		/*
2391 		 * Special case for COMPARE_AND_WRITE with fabrics
2392 		 * using SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC.
2393 		 */
2394 		u32 caw_length = cmd->t_task_nolb *
2395 				 cmd->se_dev->dev_attrib.block_size;
2396 
2397 		ret = target_alloc_sgl(&cmd->t_bidi_data_sg,
2398 				       &cmd->t_bidi_data_nents,
2399 				       caw_length, zero_flag);
2400 		if (ret < 0)
2401 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2402 	}
2403 	/*
2404 	 * If this command is not a write we can execute it right here,
2405 	 * for write buffers we need to notify the fabric driver first
2406 	 * and let it call back once the write buffers are ready.
2407 	 */
2408 	target_add_to_state_list(cmd);
2409 	if (cmd->data_direction != DMA_TO_DEVICE || cmd->data_length == 0) {
2410 		target_execute_cmd(cmd);
2411 		return 0;
2412 	}
2413 	transport_cmd_check_stop(cmd, false, true);
2414 
2415 	ret = cmd->se_tfo->write_pending(cmd);
2416 	if (ret == -EAGAIN || ret == -ENOMEM)
2417 		goto queue_full;
2418 
2419 	/* fabric drivers should only return -EAGAIN or -ENOMEM as error */
2420 	WARN_ON(ret);
2421 
2422 	return (!ret) ? 0 : TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2423 
2424 queue_full:
2425 	pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n", cmd);
2426 	cmd->t_state = TRANSPORT_COMPLETE_QF_WP;
2427 	transport_handle_queue_full(cmd, cmd->se_dev);
2428 	return 0;
2429 }
2430 EXPORT_SYMBOL(transport_generic_new_cmd);
2431 
2432 static void transport_write_pending_qf(struct se_cmd *cmd)
2433 {
2434 	int ret;
2435 
2436 	ret = cmd->se_tfo->write_pending(cmd);
2437 	if (ret == -EAGAIN || ret == -ENOMEM) {
2438 		pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n",
2439 			 cmd);
2440 		transport_handle_queue_full(cmd, cmd->se_dev);
2441 	}
2442 }
2443 
2444 int transport_generic_free_cmd(struct se_cmd *cmd, int wait_for_tasks)
2445 {
2446 	unsigned long flags;
2447 	int ret = 0;
2448 
2449 	if (!(cmd->se_cmd_flags & SCF_SE_LUN_CMD)) {
2450 		if (wait_for_tasks && (cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
2451 			 transport_wait_for_tasks(cmd);
2452 
2453 		ret = transport_release_cmd(cmd);
2454 	} else {
2455 		if (wait_for_tasks)
2456 			transport_wait_for_tasks(cmd);
2457 		/*
2458 		 * Handle WRITE failure case where transport_generic_new_cmd()
2459 		 * has already added se_cmd to state_list, but fabric has
2460 		 * failed command before I/O submission.
2461 		 */
2462 		if (cmd->state_active) {
2463 			spin_lock_irqsave(&cmd->t_state_lock, flags);
2464 			target_remove_from_state_list(cmd);
2465 			spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2466 		}
2467 
2468 		if (cmd->se_lun)
2469 			transport_lun_remove_cmd(cmd);
2470 
2471 		ret = transport_put_cmd(cmd);
2472 	}
2473 	return ret;
2474 }
2475 EXPORT_SYMBOL(transport_generic_free_cmd);
2476 
2477 /* target_get_sess_cmd - Add command to active ->sess_cmd_list
2478  * @se_cmd:	command descriptor to add
2479  * @ack_kref:	Signal that fabric will perform an ack target_put_sess_cmd()
2480  */
2481 int target_get_sess_cmd(struct se_cmd *se_cmd, bool ack_kref)
2482 {
2483 	struct se_session *se_sess = se_cmd->se_sess;
2484 	unsigned long flags;
2485 	int ret = 0;
2486 
2487 	/*
2488 	 * Add a second kref if the fabric caller is expecting to handle
2489 	 * fabric acknowledgement that requires two target_put_sess_cmd()
2490 	 * invocations before se_cmd descriptor release.
2491 	 */
2492 	if (ack_kref)
2493 		kref_get(&se_cmd->cmd_kref);
2494 
2495 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2496 	if (se_sess->sess_tearing_down) {
2497 		ret = -ESHUTDOWN;
2498 		goto out;
2499 	}
2500 	list_add_tail(&se_cmd->se_cmd_list, &se_sess->sess_cmd_list);
2501 out:
2502 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2503 
2504 	if (ret && ack_kref)
2505 		target_put_sess_cmd(se_cmd);
2506 
2507 	return ret;
2508 }
2509 EXPORT_SYMBOL(target_get_sess_cmd);
2510 
2511 static void target_release_cmd_kref(struct kref *kref)
2512 {
2513 	struct se_cmd *se_cmd = container_of(kref, struct se_cmd, cmd_kref);
2514 	struct se_session *se_sess = se_cmd->se_sess;
2515 	unsigned long flags;
2516 
2517 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2518 	if (list_empty(&se_cmd->se_cmd_list)) {
2519 		spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2520 		se_cmd->se_tfo->release_cmd(se_cmd);
2521 		return;
2522 	}
2523 	if (se_sess->sess_tearing_down && se_cmd->cmd_wait_set) {
2524 		spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2525 		complete(&se_cmd->cmd_wait_comp);
2526 		return;
2527 	}
2528 	list_del(&se_cmd->se_cmd_list);
2529 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2530 
2531 	se_cmd->se_tfo->release_cmd(se_cmd);
2532 }
2533 
2534 /* target_put_sess_cmd - Check for active I/O shutdown via kref_put
2535  * @se_cmd:	command descriptor to drop
2536  */
2537 int target_put_sess_cmd(struct se_cmd *se_cmd)
2538 {
2539 	struct se_session *se_sess = se_cmd->se_sess;
2540 
2541 	if (!se_sess) {
2542 		se_cmd->se_tfo->release_cmd(se_cmd);
2543 		return 1;
2544 	}
2545 	return kref_put(&se_cmd->cmd_kref, target_release_cmd_kref);
2546 }
2547 EXPORT_SYMBOL(target_put_sess_cmd);
2548 
2549 /* target_sess_cmd_list_set_waiting - Flag all commands in
2550  *         sess_cmd_list to complete cmd_wait_comp.  Set
2551  *         sess_tearing_down so no more commands are queued.
2552  * @se_sess:	session to flag
2553  */
2554 void target_sess_cmd_list_set_waiting(struct se_session *se_sess)
2555 {
2556 	struct se_cmd *se_cmd;
2557 	unsigned long flags;
2558 
2559 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2560 	if (se_sess->sess_tearing_down) {
2561 		spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2562 		return;
2563 	}
2564 	se_sess->sess_tearing_down = 1;
2565 	list_splice_init(&se_sess->sess_cmd_list, &se_sess->sess_wait_list);
2566 
2567 	list_for_each_entry(se_cmd, &se_sess->sess_wait_list, se_cmd_list)
2568 		se_cmd->cmd_wait_set = 1;
2569 
2570 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2571 }
2572 EXPORT_SYMBOL(target_sess_cmd_list_set_waiting);
2573 
2574 /* target_wait_for_sess_cmds - Wait for outstanding descriptors
2575  * @se_sess:    session to wait for active I/O
2576  */
2577 void target_wait_for_sess_cmds(struct se_session *se_sess)
2578 {
2579 	struct se_cmd *se_cmd, *tmp_cmd;
2580 	unsigned long flags;
2581 
2582 	list_for_each_entry_safe(se_cmd, tmp_cmd,
2583 				&se_sess->sess_wait_list, se_cmd_list) {
2584 		list_del(&se_cmd->se_cmd_list);
2585 
2586 		pr_debug("Waiting for se_cmd: %p t_state: %d, fabric state:"
2587 			" %d\n", se_cmd, se_cmd->t_state,
2588 			se_cmd->se_tfo->get_cmd_state(se_cmd));
2589 
2590 		wait_for_completion(&se_cmd->cmd_wait_comp);
2591 		pr_debug("After cmd_wait_comp: se_cmd: %p t_state: %d"
2592 			" fabric state: %d\n", se_cmd, se_cmd->t_state,
2593 			se_cmd->se_tfo->get_cmd_state(se_cmd));
2594 
2595 		se_cmd->se_tfo->release_cmd(se_cmd);
2596 	}
2597 
2598 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2599 	WARN_ON(!list_empty(&se_sess->sess_cmd_list));
2600 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2601 
2602 }
2603 EXPORT_SYMBOL(target_wait_for_sess_cmds);
2604 
2605 void transport_clear_lun_ref(struct se_lun *lun)
2606 {
2607 	percpu_ref_kill(&lun->lun_ref);
2608 	wait_for_completion(&lun->lun_ref_comp);
2609 }
2610 
2611 /**
2612  * transport_wait_for_tasks - wait for completion to occur
2613  * @cmd:	command to wait
2614  *
2615  * Called from frontend fabric context to wait for storage engine
2616  * to pause and/or release frontend generated struct se_cmd.
2617  */
2618 bool transport_wait_for_tasks(struct se_cmd *cmd)
2619 {
2620 	unsigned long flags;
2621 
2622 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2623 	if (!(cmd->se_cmd_flags & SCF_SE_LUN_CMD) &&
2624 	    !(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)) {
2625 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2626 		return false;
2627 	}
2628 
2629 	if (!(cmd->se_cmd_flags & SCF_SUPPORTED_SAM_OPCODE) &&
2630 	    !(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)) {
2631 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2632 		return false;
2633 	}
2634 
2635 	if (!(cmd->transport_state & CMD_T_ACTIVE)) {
2636 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2637 		return false;
2638 	}
2639 
2640 	cmd->transport_state |= CMD_T_STOP;
2641 
2642 	pr_debug("wait_for_tasks: Stopping %p ITT: 0x%08llx i_state: %d, t_state: %d, CMD_T_STOP\n",
2643 		cmd, cmd->tag, cmd->se_tfo->get_cmd_state(cmd), cmd->t_state);
2644 
2645 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2646 
2647 	wait_for_completion(&cmd->t_transport_stop_comp);
2648 
2649 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2650 	cmd->transport_state &= ~(CMD_T_ACTIVE | CMD_T_STOP);
2651 
2652 	pr_debug("wait_for_tasks: Stopped wait_for_completion(&cmd->t_transport_stop_comp) for ITT: 0x%08llx\n",
2653 		cmd->tag);
2654 
2655 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2656 
2657 	return true;
2658 }
2659 EXPORT_SYMBOL(transport_wait_for_tasks);
2660 
2661 struct sense_info {
2662 	u8 key;
2663 	u8 asc;
2664 	u8 ascq;
2665 	bool add_sector_info;
2666 };
2667 
2668 static const struct sense_info sense_info_table[] = {
2669 	[TCM_NO_SENSE] = {
2670 		.key = NOT_READY
2671 	},
2672 	[TCM_NON_EXISTENT_LUN] = {
2673 		.key = ILLEGAL_REQUEST,
2674 		.asc = 0x25 /* LOGICAL UNIT NOT SUPPORTED */
2675 	},
2676 	[TCM_UNSUPPORTED_SCSI_OPCODE] = {
2677 		.key = ILLEGAL_REQUEST,
2678 		.asc = 0x20, /* INVALID COMMAND OPERATION CODE */
2679 	},
2680 	[TCM_SECTOR_COUNT_TOO_MANY] = {
2681 		.key = ILLEGAL_REQUEST,
2682 		.asc = 0x20, /* INVALID COMMAND OPERATION CODE */
2683 	},
2684 	[TCM_UNKNOWN_MODE_PAGE] = {
2685 		.key = ILLEGAL_REQUEST,
2686 		.asc = 0x24, /* INVALID FIELD IN CDB */
2687 	},
2688 	[TCM_CHECK_CONDITION_ABORT_CMD] = {
2689 		.key = ABORTED_COMMAND,
2690 		.asc = 0x29, /* BUS DEVICE RESET FUNCTION OCCURRED */
2691 		.ascq = 0x03,
2692 	},
2693 	[TCM_INCORRECT_AMOUNT_OF_DATA] = {
2694 		.key = ABORTED_COMMAND,
2695 		.asc = 0x0c, /* WRITE ERROR */
2696 		.ascq = 0x0d, /* NOT ENOUGH UNSOLICITED DATA */
2697 	},
2698 	[TCM_INVALID_CDB_FIELD] = {
2699 		.key = ILLEGAL_REQUEST,
2700 		.asc = 0x24, /* INVALID FIELD IN CDB */
2701 	},
2702 	[TCM_INVALID_PARAMETER_LIST] = {
2703 		.key = ILLEGAL_REQUEST,
2704 		.asc = 0x26, /* INVALID FIELD IN PARAMETER LIST */
2705 	},
2706 	[TCM_PARAMETER_LIST_LENGTH_ERROR] = {
2707 		.key = ILLEGAL_REQUEST,
2708 		.asc = 0x1a, /* PARAMETER LIST LENGTH ERROR */
2709 	},
2710 	[TCM_UNEXPECTED_UNSOLICITED_DATA] = {
2711 		.key = ILLEGAL_REQUEST,
2712 		.asc = 0x0c, /* WRITE ERROR */
2713 		.ascq = 0x0c, /* UNEXPECTED_UNSOLICITED_DATA */
2714 	},
2715 	[TCM_SERVICE_CRC_ERROR] = {
2716 		.key = ABORTED_COMMAND,
2717 		.asc = 0x47, /* PROTOCOL SERVICE CRC ERROR */
2718 		.ascq = 0x05, /* N/A */
2719 	},
2720 	[TCM_SNACK_REJECTED] = {
2721 		.key = ABORTED_COMMAND,
2722 		.asc = 0x11, /* READ ERROR */
2723 		.ascq = 0x13, /* FAILED RETRANSMISSION REQUEST */
2724 	},
2725 	[TCM_WRITE_PROTECTED] = {
2726 		.key = DATA_PROTECT,
2727 		.asc = 0x27, /* WRITE PROTECTED */
2728 	},
2729 	[TCM_ADDRESS_OUT_OF_RANGE] = {
2730 		.key = ILLEGAL_REQUEST,
2731 		.asc = 0x21, /* LOGICAL BLOCK ADDRESS OUT OF RANGE */
2732 	},
2733 	[TCM_CHECK_CONDITION_UNIT_ATTENTION] = {
2734 		.key = UNIT_ATTENTION,
2735 	},
2736 	[TCM_CHECK_CONDITION_NOT_READY] = {
2737 		.key = NOT_READY,
2738 	},
2739 	[TCM_MISCOMPARE_VERIFY] = {
2740 		.key = MISCOMPARE,
2741 		.asc = 0x1d, /* MISCOMPARE DURING VERIFY OPERATION */
2742 		.ascq = 0x00,
2743 	},
2744 	[TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED] = {
2745 		.key = ABORTED_COMMAND,
2746 		.asc = 0x10,
2747 		.ascq = 0x01, /* LOGICAL BLOCK GUARD CHECK FAILED */
2748 		.add_sector_info = true,
2749 	},
2750 	[TCM_LOGICAL_BLOCK_APP_TAG_CHECK_FAILED] = {
2751 		.key = ABORTED_COMMAND,
2752 		.asc = 0x10,
2753 		.ascq = 0x02, /* LOGICAL BLOCK APPLICATION TAG CHECK FAILED */
2754 		.add_sector_info = true,
2755 	},
2756 	[TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED] = {
2757 		.key = ABORTED_COMMAND,
2758 		.asc = 0x10,
2759 		.ascq = 0x03, /* LOGICAL BLOCK REFERENCE TAG CHECK FAILED */
2760 		.add_sector_info = true,
2761 	},
2762 	[TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE] = {
2763 		/*
2764 		 * Returning ILLEGAL REQUEST would cause immediate IO errors on
2765 		 * Solaris initiators.  Returning NOT READY instead means the
2766 		 * operations will be retried a finite number of times and we
2767 		 * can survive intermittent errors.
2768 		 */
2769 		.key = NOT_READY,
2770 		.asc = 0x08, /* LOGICAL UNIT COMMUNICATION FAILURE */
2771 	},
2772 };
2773 
2774 static int translate_sense_reason(struct se_cmd *cmd, sense_reason_t reason)
2775 {
2776 	const struct sense_info *si;
2777 	u8 *buffer = cmd->sense_buffer;
2778 	int r = (__force int)reason;
2779 	u8 asc, ascq;
2780 	bool desc_format = target_sense_desc_format(cmd->se_dev);
2781 
2782 	if (r < ARRAY_SIZE(sense_info_table) && sense_info_table[r].key)
2783 		si = &sense_info_table[r];
2784 	else
2785 		si = &sense_info_table[(__force int)
2786 				       TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE];
2787 
2788 	if (reason == TCM_CHECK_CONDITION_UNIT_ATTENTION) {
2789 		core_scsi3_ua_for_check_condition(cmd, &asc, &ascq);
2790 		WARN_ON_ONCE(asc == 0);
2791 	} else if (si->asc == 0) {
2792 		WARN_ON_ONCE(cmd->scsi_asc == 0);
2793 		asc = cmd->scsi_asc;
2794 		ascq = cmd->scsi_ascq;
2795 	} else {
2796 		asc = si->asc;
2797 		ascq = si->ascq;
2798 	}
2799 
2800 	scsi_build_sense_buffer(desc_format, buffer, si->key, asc, ascq);
2801 	if (si->add_sector_info)
2802 		return scsi_set_sense_information(buffer,
2803 						  cmd->scsi_sense_length,
2804 						  cmd->bad_sector);
2805 
2806 	return 0;
2807 }
2808 
2809 int
2810 transport_send_check_condition_and_sense(struct se_cmd *cmd,
2811 		sense_reason_t reason, int from_transport)
2812 {
2813 	unsigned long flags;
2814 
2815 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2816 	if (cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION) {
2817 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2818 		return 0;
2819 	}
2820 	cmd->se_cmd_flags |= SCF_SENT_CHECK_CONDITION;
2821 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2822 
2823 	if (!from_transport) {
2824 		int rc;
2825 
2826 		cmd->se_cmd_flags |= SCF_EMULATED_TASK_SENSE;
2827 		cmd->scsi_status = SAM_STAT_CHECK_CONDITION;
2828 		cmd->scsi_sense_length  = TRANSPORT_SENSE_BUFFER;
2829 		rc = translate_sense_reason(cmd, reason);
2830 		if (rc)
2831 			return rc;
2832 	}
2833 
2834 	trace_target_cmd_complete(cmd);
2835 	return cmd->se_tfo->queue_status(cmd);
2836 }
2837 EXPORT_SYMBOL(transport_send_check_condition_and_sense);
2838 
2839 int transport_check_aborted_status(struct se_cmd *cmd, int send_status)
2840 {
2841 	if (!(cmd->transport_state & CMD_T_ABORTED))
2842 		return 0;
2843 
2844 	/*
2845 	 * If cmd has been aborted but either no status is to be sent or it has
2846 	 * already been sent, just return
2847 	 */
2848 	if (!send_status || !(cmd->se_cmd_flags & SCF_SEND_DELAYED_TAS))
2849 		return 1;
2850 
2851 	pr_debug("Sending delayed SAM_STAT_TASK_ABORTED status for CDB: 0x%02x ITT: 0x%08llx\n",
2852 		 cmd->t_task_cdb[0], cmd->tag);
2853 
2854 	cmd->se_cmd_flags &= ~SCF_SEND_DELAYED_TAS;
2855 	cmd->scsi_status = SAM_STAT_TASK_ABORTED;
2856 	trace_target_cmd_complete(cmd);
2857 	cmd->se_tfo->queue_status(cmd);
2858 
2859 	return 1;
2860 }
2861 EXPORT_SYMBOL(transport_check_aborted_status);
2862 
2863 void transport_send_task_abort(struct se_cmd *cmd)
2864 {
2865 	unsigned long flags;
2866 
2867 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2868 	if (cmd->se_cmd_flags & (SCF_SENT_CHECK_CONDITION)) {
2869 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2870 		return;
2871 	}
2872 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2873 
2874 	/*
2875 	 * If there are still expected incoming fabric WRITEs, we wait
2876 	 * until until they have completed before sending a TASK_ABORTED
2877 	 * response.  This response with TASK_ABORTED status will be
2878 	 * queued back to fabric module by transport_check_aborted_status().
2879 	 */
2880 	if (cmd->data_direction == DMA_TO_DEVICE) {
2881 		if (cmd->se_tfo->write_pending_status(cmd) != 0) {
2882 			cmd->transport_state |= CMD_T_ABORTED;
2883 			cmd->se_cmd_flags |= SCF_SEND_DELAYED_TAS;
2884 			return;
2885 		}
2886 	}
2887 	cmd->scsi_status = SAM_STAT_TASK_ABORTED;
2888 
2889 	transport_lun_remove_cmd(cmd);
2890 
2891 	pr_debug("Setting SAM_STAT_TASK_ABORTED status for CDB: 0x%02x, ITT: 0x%08llx\n",
2892 		 cmd->t_task_cdb[0], cmd->tag);
2893 
2894 	trace_target_cmd_complete(cmd);
2895 	cmd->se_tfo->queue_status(cmd);
2896 }
2897 
2898 static void target_tmr_work(struct work_struct *work)
2899 {
2900 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
2901 	struct se_device *dev = cmd->se_dev;
2902 	struct se_tmr_req *tmr = cmd->se_tmr_req;
2903 	int ret;
2904 
2905 	switch (tmr->function) {
2906 	case TMR_ABORT_TASK:
2907 		core_tmr_abort_task(dev, tmr, cmd->se_sess);
2908 		break;
2909 	case TMR_ABORT_TASK_SET:
2910 	case TMR_CLEAR_ACA:
2911 	case TMR_CLEAR_TASK_SET:
2912 		tmr->response = TMR_TASK_MGMT_FUNCTION_NOT_SUPPORTED;
2913 		break;
2914 	case TMR_LUN_RESET:
2915 		ret = core_tmr_lun_reset(dev, tmr, NULL, NULL);
2916 		tmr->response = (!ret) ? TMR_FUNCTION_COMPLETE :
2917 					 TMR_FUNCTION_REJECTED;
2918 		if (tmr->response == TMR_FUNCTION_COMPLETE) {
2919 			target_ua_allocate_lun(cmd->se_sess->se_node_acl,
2920 					       cmd->orig_fe_lun, 0x29,
2921 					       ASCQ_29H_BUS_DEVICE_RESET_FUNCTION_OCCURRED);
2922 		}
2923 		break;
2924 	case TMR_TARGET_WARM_RESET:
2925 		tmr->response = TMR_FUNCTION_REJECTED;
2926 		break;
2927 	case TMR_TARGET_COLD_RESET:
2928 		tmr->response = TMR_FUNCTION_REJECTED;
2929 		break;
2930 	default:
2931 		pr_err("Uknown TMR function: 0x%02x.\n",
2932 				tmr->function);
2933 		tmr->response = TMR_FUNCTION_REJECTED;
2934 		break;
2935 	}
2936 
2937 	cmd->t_state = TRANSPORT_ISTATE_PROCESSING;
2938 	cmd->se_tfo->queue_tm_rsp(cmd);
2939 
2940 	transport_cmd_check_stop_to_fabric(cmd);
2941 }
2942 
2943 int transport_generic_handle_tmr(
2944 	struct se_cmd *cmd)
2945 {
2946 	unsigned long flags;
2947 
2948 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2949 	cmd->transport_state |= CMD_T_ACTIVE;
2950 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2951 
2952 	INIT_WORK(&cmd->work, target_tmr_work);
2953 	queue_work(cmd->se_dev->tmr_wq, &cmd->work);
2954 	return 0;
2955 }
2956 EXPORT_SYMBOL(transport_generic_handle_tmr);
2957 
2958 bool
2959 target_check_wce(struct se_device *dev)
2960 {
2961 	bool wce = false;
2962 
2963 	if (dev->transport->get_write_cache)
2964 		wce = dev->transport->get_write_cache(dev);
2965 	else if (dev->dev_attrib.emulate_write_cache > 0)
2966 		wce = true;
2967 
2968 	return wce;
2969 }
2970 
2971 bool
2972 target_check_fua(struct se_device *dev)
2973 {
2974 	return target_check_wce(dev) && dev->dev_attrib.emulate_fua_write > 0;
2975 }
2976