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/blkdev.h>
32 #include <linux/spinlock.h>
33 #include <linux/kthread.h>
34 #include <linux/in.h>
35 #include <linux/cdrom.h>
36 #include <linux/module.h>
37 #include <linux/ratelimit.h>
38 #include <asm/unaligned.h>
39 #include <net/sock.h>
40 #include <net/tcp.h>
41 #include <scsi/scsi.h>
42 #include <scsi/scsi_cmnd.h>
43 #include <scsi/scsi_tcq.h>
44 
45 #include <target/target_core_base.h>
46 #include <target/target_core_backend.h>
47 #include <target/target_core_fabric.h>
48 #include <target/target_core_configfs.h>
49 
50 #include "target_core_internal.h"
51 #include "target_core_alua.h"
52 #include "target_core_pr.h"
53 #include "target_core_ua.h"
54 
55 #define CREATE_TRACE_POINTS
56 #include <trace/events/target.h>
57 
58 static struct workqueue_struct *target_completion_wq;
59 static struct kmem_cache *se_sess_cache;
60 struct kmem_cache *se_ua_cache;
61 struct kmem_cache *t10_pr_reg_cache;
62 struct kmem_cache *t10_alua_lu_gp_cache;
63 struct kmem_cache *t10_alua_lu_gp_mem_cache;
64 struct kmem_cache *t10_alua_tg_pt_gp_cache;
65 struct kmem_cache *t10_alua_tg_pt_gp_mem_cache;
66 
67 static void transport_complete_task_attr(struct se_cmd *cmd);
68 static void transport_handle_queue_full(struct se_cmd *cmd,
69 		struct se_device *dev);
70 static int transport_put_cmd(struct se_cmd *cmd);
71 static void target_complete_ok_work(struct work_struct *work);
72 
73 int init_se_kmem_caches(void)
74 {
75 	se_sess_cache = kmem_cache_create("se_sess_cache",
76 			sizeof(struct se_session), __alignof__(struct se_session),
77 			0, NULL);
78 	if (!se_sess_cache) {
79 		pr_err("kmem_cache_create() for struct se_session"
80 				" failed\n");
81 		goto out;
82 	}
83 	se_ua_cache = kmem_cache_create("se_ua_cache",
84 			sizeof(struct se_ua), __alignof__(struct se_ua),
85 			0, NULL);
86 	if (!se_ua_cache) {
87 		pr_err("kmem_cache_create() for struct se_ua failed\n");
88 		goto out_free_sess_cache;
89 	}
90 	t10_pr_reg_cache = kmem_cache_create("t10_pr_reg_cache",
91 			sizeof(struct t10_pr_registration),
92 			__alignof__(struct t10_pr_registration), 0, NULL);
93 	if (!t10_pr_reg_cache) {
94 		pr_err("kmem_cache_create() for struct t10_pr_registration"
95 				" failed\n");
96 		goto out_free_ua_cache;
97 	}
98 	t10_alua_lu_gp_cache = kmem_cache_create("t10_alua_lu_gp_cache",
99 			sizeof(struct t10_alua_lu_gp), __alignof__(struct t10_alua_lu_gp),
100 			0, NULL);
101 	if (!t10_alua_lu_gp_cache) {
102 		pr_err("kmem_cache_create() for t10_alua_lu_gp_cache"
103 				" failed\n");
104 		goto out_free_pr_reg_cache;
105 	}
106 	t10_alua_lu_gp_mem_cache = kmem_cache_create("t10_alua_lu_gp_mem_cache",
107 			sizeof(struct t10_alua_lu_gp_member),
108 			__alignof__(struct t10_alua_lu_gp_member), 0, NULL);
109 	if (!t10_alua_lu_gp_mem_cache) {
110 		pr_err("kmem_cache_create() for t10_alua_lu_gp_mem_"
111 				"cache failed\n");
112 		goto out_free_lu_gp_cache;
113 	}
114 	t10_alua_tg_pt_gp_cache = kmem_cache_create("t10_alua_tg_pt_gp_cache",
115 			sizeof(struct t10_alua_tg_pt_gp),
116 			__alignof__(struct t10_alua_tg_pt_gp), 0, NULL);
117 	if (!t10_alua_tg_pt_gp_cache) {
118 		pr_err("kmem_cache_create() for t10_alua_tg_pt_gp_"
119 				"cache failed\n");
120 		goto out_free_lu_gp_mem_cache;
121 	}
122 	t10_alua_tg_pt_gp_mem_cache = kmem_cache_create(
123 			"t10_alua_tg_pt_gp_mem_cache",
124 			sizeof(struct t10_alua_tg_pt_gp_member),
125 			__alignof__(struct t10_alua_tg_pt_gp_member),
126 			0, NULL);
127 	if (!t10_alua_tg_pt_gp_mem_cache) {
128 		pr_err("kmem_cache_create() for t10_alua_tg_pt_gp_"
129 				"mem_t failed\n");
130 		goto out_free_tg_pt_gp_cache;
131 	}
132 
133 	target_completion_wq = alloc_workqueue("target_completion",
134 					       WQ_MEM_RECLAIM, 0);
135 	if (!target_completion_wq)
136 		goto out_free_tg_pt_gp_mem_cache;
137 
138 	return 0;
139 
140 out_free_tg_pt_gp_mem_cache:
141 	kmem_cache_destroy(t10_alua_tg_pt_gp_mem_cache);
142 out_free_tg_pt_gp_cache:
143 	kmem_cache_destroy(t10_alua_tg_pt_gp_cache);
144 out_free_lu_gp_mem_cache:
145 	kmem_cache_destroy(t10_alua_lu_gp_mem_cache);
146 out_free_lu_gp_cache:
147 	kmem_cache_destroy(t10_alua_lu_gp_cache);
148 out_free_pr_reg_cache:
149 	kmem_cache_destroy(t10_pr_reg_cache);
150 out_free_ua_cache:
151 	kmem_cache_destroy(se_ua_cache);
152 out_free_sess_cache:
153 	kmem_cache_destroy(se_sess_cache);
154 out:
155 	return -ENOMEM;
156 }
157 
158 void release_se_kmem_caches(void)
159 {
160 	destroy_workqueue(target_completion_wq);
161 	kmem_cache_destroy(se_sess_cache);
162 	kmem_cache_destroy(se_ua_cache);
163 	kmem_cache_destroy(t10_pr_reg_cache);
164 	kmem_cache_destroy(t10_alua_lu_gp_cache);
165 	kmem_cache_destroy(t10_alua_lu_gp_mem_cache);
166 	kmem_cache_destroy(t10_alua_tg_pt_gp_cache);
167 	kmem_cache_destroy(t10_alua_tg_pt_gp_mem_cache);
168 }
169 
170 /* This code ensures unique mib indexes are handed out. */
171 static DEFINE_SPINLOCK(scsi_mib_index_lock);
172 static u32 scsi_mib_index[SCSI_INDEX_TYPE_MAX];
173 
174 /*
175  * Allocate a new row index for the entry type specified
176  */
177 u32 scsi_get_new_index(scsi_index_t type)
178 {
179 	u32 new_index;
180 
181 	BUG_ON((type < 0) || (type >= SCSI_INDEX_TYPE_MAX));
182 
183 	spin_lock(&scsi_mib_index_lock);
184 	new_index = ++scsi_mib_index[type];
185 	spin_unlock(&scsi_mib_index_lock);
186 
187 	return new_index;
188 }
189 
190 void transport_subsystem_check_init(void)
191 {
192 	int ret;
193 	static int sub_api_initialized;
194 
195 	if (sub_api_initialized)
196 		return;
197 
198 	ret = request_module("target_core_iblock");
199 	if (ret != 0)
200 		pr_err("Unable to load target_core_iblock\n");
201 
202 	ret = request_module("target_core_file");
203 	if (ret != 0)
204 		pr_err("Unable to load target_core_file\n");
205 
206 	ret = request_module("target_core_pscsi");
207 	if (ret != 0)
208 		pr_err("Unable to load target_core_pscsi\n");
209 
210 	sub_api_initialized = 1;
211 }
212 
213 struct se_session *transport_init_session(void)
214 {
215 	struct se_session *se_sess;
216 
217 	se_sess = kmem_cache_zalloc(se_sess_cache, GFP_KERNEL);
218 	if (!se_sess) {
219 		pr_err("Unable to allocate struct se_session from"
220 				" se_sess_cache\n");
221 		return ERR_PTR(-ENOMEM);
222 	}
223 	INIT_LIST_HEAD(&se_sess->sess_list);
224 	INIT_LIST_HEAD(&se_sess->sess_acl_list);
225 	INIT_LIST_HEAD(&se_sess->sess_cmd_list);
226 	INIT_LIST_HEAD(&se_sess->sess_wait_list);
227 	spin_lock_init(&se_sess->sess_cmd_lock);
228 	kref_init(&se_sess->sess_kref);
229 
230 	return se_sess;
231 }
232 EXPORT_SYMBOL(transport_init_session);
233 
234 int transport_alloc_session_tags(struct se_session *se_sess,
235 			         unsigned int tag_num, unsigned int tag_size)
236 {
237 	int rc;
238 
239 	se_sess->sess_cmd_map = kzalloc(tag_num * tag_size, GFP_KERNEL);
240 	if (!se_sess->sess_cmd_map) {
241 		pr_err("Unable to allocate se_sess->sess_cmd_map\n");
242 		return -ENOMEM;
243 	}
244 
245 	rc = percpu_ida_init(&se_sess->sess_tag_pool, tag_num);
246 	if (rc < 0) {
247 		pr_err("Unable to init se_sess->sess_tag_pool,"
248 			" tag_num: %u\n", tag_num);
249 		kfree(se_sess->sess_cmd_map);
250 		se_sess->sess_cmd_map = NULL;
251 		return -ENOMEM;
252 	}
253 
254 	return 0;
255 }
256 EXPORT_SYMBOL(transport_alloc_session_tags);
257 
258 struct se_session *transport_init_session_tags(unsigned int tag_num,
259 					       unsigned int tag_size)
260 {
261 	struct se_session *se_sess;
262 	int rc;
263 
264 	se_sess = transport_init_session();
265 	if (IS_ERR(se_sess))
266 		return se_sess;
267 
268 	rc = transport_alloc_session_tags(se_sess, tag_num, tag_size);
269 	if (rc < 0) {
270 		transport_free_session(se_sess);
271 		return ERR_PTR(-ENOMEM);
272 	}
273 
274 	return se_sess;
275 }
276 EXPORT_SYMBOL(transport_init_session_tags);
277 
278 /*
279  * Called with spin_lock_irqsave(&struct se_portal_group->session_lock called.
280  */
281 void __transport_register_session(
282 	struct se_portal_group *se_tpg,
283 	struct se_node_acl *se_nacl,
284 	struct se_session *se_sess,
285 	void *fabric_sess_ptr)
286 {
287 	unsigned char buf[PR_REG_ISID_LEN];
288 
289 	se_sess->se_tpg = se_tpg;
290 	se_sess->fabric_sess_ptr = fabric_sess_ptr;
291 	/*
292 	 * Used by struct se_node_acl's under ConfigFS to locate active se_session-t
293 	 *
294 	 * Only set for struct se_session's that will actually be moving I/O.
295 	 * eg: *NOT* discovery sessions.
296 	 */
297 	if (se_nacl) {
298 		/*
299 		 * If the fabric module supports an ISID based TransportID,
300 		 * save this value in binary from the fabric I_T Nexus now.
301 		 */
302 		if (se_tpg->se_tpg_tfo->sess_get_initiator_sid != NULL) {
303 			memset(&buf[0], 0, PR_REG_ISID_LEN);
304 			se_tpg->se_tpg_tfo->sess_get_initiator_sid(se_sess,
305 					&buf[0], PR_REG_ISID_LEN);
306 			se_sess->sess_bin_isid = get_unaligned_be64(&buf[0]);
307 		}
308 		kref_get(&se_nacl->acl_kref);
309 
310 		spin_lock_irq(&se_nacl->nacl_sess_lock);
311 		/*
312 		 * The se_nacl->nacl_sess pointer will be set to the
313 		 * last active I_T Nexus for each struct se_node_acl.
314 		 */
315 		se_nacl->nacl_sess = se_sess;
316 
317 		list_add_tail(&se_sess->sess_acl_list,
318 			      &se_nacl->acl_sess_list);
319 		spin_unlock_irq(&se_nacl->nacl_sess_lock);
320 	}
321 	list_add_tail(&se_sess->sess_list, &se_tpg->tpg_sess_list);
322 
323 	pr_debug("TARGET_CORE[%s]: Registered fabric_sess_ptr: %p\n",
324 		se_tpg->se_tpg_tfo->get_fabric_name(), se_sess->fabric_sess_ptr);
325 }
326 EXPORT_SYMBOL(__transport_register_session);
327 
328 void transport_register_session(
329 	struct se_portal_group *se_tpg,
330 	struct se_node_acl *se_nacl,
331 	struct se_session *se_sess,
332 	void *fabric_sess_ptr)
333 {
334 	unsigned long flags;
335 
336 	spin_lock_irqsave(&se_tpg->session_lock, flags);
337 	__transport_register_session(se_tpg, se_nacl, se_sess, fabric_sess_ptr);
338 	spin_unlock_irqrestore(&se_tpg->session_lock, flags);
339 }
340 EXPORT_SYMBOL(transport_register_session);
341 
342 static void target_release_session(struct kref *kref)
343 {
344 	struct se_session *se_sess = container_of(kref,
345 			struct se_session, sess_kref);
346 	struct se_portal_group *se_tpg = se_sess->se_tpg;
347 
348 	se_tpg->se_tpg_tfo->close_session(se_sess);
349 }
350 
351 void target_get_session(struct se_session *se_sess)
352 {
353 	kref_get(&se_sess->sess_kref);
354 }
355 EXPORT_SYMBOL(target_get_session);
356 
357 void target_put_session(struct se_session *se_sess)
358 {
359 	struct se_portal_group *tpg = se_sess->se_tpg;
360 
361 	if (tpg->se_tpg_tfo->put_session != NULL) {
362 		tpg->se_tpg_tfo->put_session(se_sess);
363 		return;
364 	}
365 	kref_put(&se_sess->sess_kref, target_release_session);
366 }
367 EXPORT_SYMBOL(target_put_session);
368 
369 static void target_complete_nacl(struct kref *kref)
370 {
371 	struct se_node_acl *nacl = container_of(kref,
372 				struct se_node_acl, acl_kref);
373 
374 	complete(&nacl->acl_free_comp);
375 }
376 
377 void target_put_nacl(struct se_node_acl *nacl)
378 {
379 	kref_put(&nacl->acl_kref, target_complete_nacl);
380 }
381 
382 void transport_deregister_session_configfs(struct se_session *se_sess)
383 {
384 	struct se_node_acl *se_nacl;
385 	unsigned long flags;
386 	/*
387 	 * Used by struct se_node_acl's under ConfigFS to locate active struct se_session
388 	 */
389 	se_nacl = se_sess->se_node_acl;
390 	if (se_nacl) {
391 		spin_lock_irqsave(&se_nacl->nacl_sess_lock, flags);
392 		if (se_nacl->acl_stop == 0)
393 			list_del(&se_sess->sess_acl_list);
394 		/*
395 		 * If the session list is empty, then clear the pointer.
396 		 * Otherwise, set the struct se_session pointer from the tail
397 		 * element of the per struct se_node_acl active session list.
398 		 */
399 		if (list_empty(&se_nacl->acl_sess_list))
400 			se_nacl->nacl_sess = NULL;
401 		else {
402 			se_nacl->nacl_sess = container_of(
403 					se_nacl->acl_sess_list.prev,
404 					struct se_session, sess_acl_list);
405 		}
406 		spin_unlock_irqrestore(&se_nacl->nacl_sess_lock, flags);
407 	}
408 }
409 EXPORT_SYMBOL(transport_deregister_session_configfs);
410 
411 void transport_free_session(struct se_session *se_sess)
412 {
413 	if (se_sess->sess_cmd_map) {
414 		percpu_ida_destroy(&se_sess->sess_tag_pool);
415 		kfree(se_sess->sess_cmd_map);
416 	}
417 	kmem_cache_free(se_sess_cache, se_sess);
418 }
419 EXPORT_SYMBOL(transport_free_session);
420 
421 void transport_deregister_session(struct se_session *se_sess)
422 {
423 	struct se_portal_group *se_tpg = se_sess->se_tpg;
424 	struct target_core_fabric_ops *se_tfo;
425 	struct se_node_acl *se_nacl;
426 	unsigned long flags;
427 	bool comp_nacl = true;
428 
429 	if (!se_tpg) {
430 		transport_free_session(se_sess);
431 		return;
432 	}
433 	se_tfo = se_tpg->se_tpg_tfo;
434 
435 	spin_lock_irqsave(&se_tpg->session_lock, flags);
436 	list_del(&se_sess->sess_list);
437 	se_sess->se_tpg = NULL;
438 	se_sess->fabric_sess_ptr = NULL;
439 	spin_unlock_irqrestore(&se_tpg->session_lock, flags);
440 
441 	/*
442 	 * Determine if we need to do extra work for this initiator node's
443 	 * struct se_node_acl if it had been previously dynamically generated.
444 	 */
445 	se_nacl = se_sess->se_node_acl;
446 
447 	spin_lock_irqsave(&se_tpg->acl_node_lock, flags);
448 	if (se_nacl && se_nacl->dynamic_node_acl) {
449 		if (!se_tfo->tpg_check_demo_mode_cache(se_tpg)) {
450 			list_del(&se_nacl->acl_list);
451 			se_tpg->num_node_acls--;
452 			spin_unlock_irqrestore(&se_tpg->acl_node_lock, flags);
453 			core_tpg_wait_for_nacl_pr_ref(se_nacl);
454 			core_free_device_list_for_node(se_nacl, se_tpg);
455 			se_tfo->tpg_release_fabric_acl(se_tpg, se_nacl);
456 
457 			comp_nacl = false;
458 			spin_lock_irqsave(&se_tpg->acl_node_lock, flags);
459 		}
460 	}
461 	spin_unlock_irqrestore(&se_tpg->acl_node_lock, flags);
462 
463 	pr_debug("TARGET_CORE[%s]: Deregistered fabric_sess\n",
464 		se_tpg->se_tpg_tfo->get_fabric_name());
465 	/*
466 	 * If last kref is dropping now for an explict NodeACL, awake sleeping
467 	 * ->acl_free_comp caller to wakeup configfs se_node_acl->acl_group
468 	 * removal context.
469 	 */
470 	if (se_nacl && comp_nacl == true)
471 		target_put_nacl(se_nacl);
472 
473 	transport_free_session(se_sess);
474 }
475 EXPORT_SYMBOL(transport_deregister_session);
476 
477 /*
478  * Called with cmd->t_state_lock held.
479  */
480 static void target_remove_from_state_list(struct se_cmd *cmd)
481 {
482 	struct se_device *dev = cmd->se_dev;
483 	unsigned long flags;
484 
485 	if (!dev)
486 		return;
487 
488 	if (cmd->transport_state & CMD_T_BUSY)
489 		return;
490 
491 	spin_lock_irqsave(&dev->execute_task_lock, flags);
492 	if (cmd->state_active) {
493 		list_del(&cmd->state_list);
494 		cmd->state_active = false;
495 	}
496 	spin_unlock_irqrestore(&dev->execute_task_lock, flags);
497 }
498 
499 static int transport_cmd_check_stop(struct se_cmd *cmd, bool remove_from_lists,
500 				    bool write_pending)
501 {
502 	unsigned long flags;
503 
504 	spin_lock_irqsave(&cmd->t_state_lock, flags);
505 	if (write_pending)
506 		cmd->t_state = TRANSPORT_WRITE_PENDING;
507 
508 	/*
509 	 * Determine if IOCTL context caller in requesting the stopping of this
510 	 * command for LUN shutdown purposes.
511 	 */
512 	if (cmd->transport_state & CMD_T_LUN_STOP) {
513 		pr_debug("%s:%d CMD_T_LUN_STOP for ITT: 0x%08x\n",
514 			__func__, __LINE__, cmd->se_tfo->get_task_tag(cmd));
515 
516 		cmd->transport_state &= ~CMD_T_ACTIVE;
517 		if (remove_from_lists)
518 			target_remove_from_state_list(cmd);
519 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
520 
521 		complete(&cmd->transport_lun_stop_comp);
522 		return 1;
523 	}
524 
525 	if (remove_from_lists) {
526 		target_remove_from_state_list(cmd);
527 
528 		/*
529 		 * Clear struct se_cmd->se_lun before the handoff to FE.
530 		 */
531 		cmd->se_lun = NULL;
532 	}
533 
534 	/*
535 	 * Determine if frontend context caller is requesting the stopping of
536 	 * this command for frontend exceptions.
537 	 */
538 	if (cmd->transport_state & CMD_T_STOP) {
539 		pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08x\n",
540 			__func__, __LINE__,
541 			cmd->se_tfo->get_task_tag(cmd));
542 
543 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
544 
545 		complete(&cmd->t_transport_stop_comp);
546 		return 1;
547 	}
548 
549 	cmd->transport_state &= ~CMD_T_ACTIVE;
550 	if (remove_from_lists) {
551 		/*
552 		 * Some fabric modules like tcm_loop can release
553 		 * their internally allocated I/O reference now and
554 		 * struct se_cmd now.
555 		 *
556 		 * Fabric modules are expected to return '1' here if the
557 		 * se_cmd being passed is released at this point,
558 		 * or zero if not being released.
559 		 */
560 		if (cmd->se_tfo->check_stop_free != NULL) {
561 			spin_unlock_irqrestore(&cmd->t_state_lock, flags);
562 			return cmd->se_tfo->check_stop_free(cmd);
563 		}
564 	}
565 
566 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
567 	return 0;
568 }
569 
570 static int transport_cmd_check_stop_to_fabric(struct se_cmd *cmd)
571 {
572 	return transport_cmd_check_stop(cmd, true, false);
573 }
574 
575 static void transport_lun_remove_cmd(struct se_cmd *cmd)
576 {
577 	struct se_lun *lun = cmd->se_lun;
578 	unsigned long flags;
579 
580 	if (!lun)
581 		return;
582 
583 	spin_lock_irqsave(&lun->lun_cmd_lock, flags);
584 	if (!list_empty(&cmd->se_lun_node))
585 		list_del_init(&cmd->se_lun_node);
586 	spin_unlock_irqrestore(&lun->lun_cmd_lock, flags);
587 }
588 
589 void transport_cmd_finish_abort(struct se_cmd *cmd, int remove)
590 {
591 	if (transport_cmd_check_stop_to_fabric(cmd))
592 		return;
593 	if (remove)
594 		transport_put_cmd(cmd);
595 }
596 
597 static void target_complete_failure_work(struct work_struct *work)
598 {
599 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
600 
601 	transport_generic_request_failure(cmd,
602 			TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE);
603 }
604 
605 /*
606  * Used when asking transport to copy Sense Data from the underlying
607  * Linux/SCSI struct scsi_cmnd
608  */
609 static unsigned char *transport_get_sense_buffer(struct se_cmd *cmd)
610 {
611 	struct se_device *dev = cmd->se_dev;
612 
613 	WARN_ON(!cmd->se_lun);
614 
615 	if (!dev)
616 		return NULL;
617 
618 	if (cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION)
619 		return NULL;
620 
621 	cmd->scsi_sense_length = TRANSPORT_SENSE_BUFFER;
622 
623 	pr_debug("HBA_[%u]_PLUG[%s]: Requesting sense for SAM STATUS: 0x%02x\n",
624 		dev->se_hba->hba_id, dev->transport->name, cmd->scsi_status);
625 	return cmd->sense_buffer;
626 }
627 
628 void target_complete_cmd(struct se_cmd *cmd, u8 scsi_status)
629 {
630 	struct se_device *dev = cmd->se_dev;
631 	int success = scsi_status == GOOD;
632 	unsigned long flags;
633 
634 	cmd->scsi_status = scsi_status;
635 
636 
637 	spin_lock_irqsave(&cmd->t_state_lock, flags);
638 	cmd->transport_state &= ~CMD_T_BUSY;
639 
640 	if (dev && dev->transport->transport_complete) {
641 		dev->transport->transport_complete(cmd,
642 				cmd->t_data_sg,
643 				transport_get_sense_buffer(cmd));
644 		if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE)
645 			success = 1;
646 	}
647 
648 	/*
649 	 * See if we are waiting to complete for an exception condition.
650 	 */
651 	if (cmd->transport_state & CMD_T_REQUEST_STOP) {
652 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
653 		complete(&cmd->task_stop_comp);
654 		return;
655 	}
656 
657 	if (!success)
658 		cmd->transport_state |= CMD_T_FAILED;
659 
660 	/*
661 	 * Check for case where an explict ABORT_TASK has been received
662 	 * and transport_wait_for_tasks() will be waiting for completion..
663 	 */
664 	if (cmd->transport_state & CMD_T_ABORTED &&
665 	    cmd->transport_state & CMD_T_STOP) {
666 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
667 		complete(&cmd->t_transport_stop_comp);
668 		return;
669 	} else if (cmd->transport_state & CMD_T_FAILED) {
670 		INIT_WORK(&cmd->work, target_complete_failure_work);
671 	} else {
672 		INIT_WORK(&cmd->work, target_complete_ok_work);
673 	}
674 
675 	cmd->t_state = TRANSPORT_COMPLETE;
676 	cmd->transport_state |= (CMD_T_COMPLETE | CMD_T_ACTIVE);
677 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
678 
679 	queue_work(target_completion_wq, &cmd->work);
680 }
681 EXPORT_SYMBOL(target_complete_cmd);
682 
683 static void target_add_to_state_list(struct se_cmd *cmd)
684 {
685 	struct se_device *dev = cmd->se_dev;
686 	unsigned long flags;
687 
688 	spin_lock_irqsave(&dev->execute_task_lock, flags);
689 	if (!cmd->state_active) {
690 		list_add_tail(&cmd->state_list, &dev->state_list);
691 		cmd->state_active = true;
692 	}
693 	spin_unlock_irqrestore(&dev->execute_task_lock, flags);
694 }
695 
696 /*
697  * Handle QUEUE_FULL / -EAGAIN and -ENOMEM status
698  */
699 static void transport_write_pending_qf(struct se_cmd *cmd);
700 static void transport_complete_qf(struct se_cmd *cmd);
701 
702 void target_qf_do_work(struct work_struct *work)
703 {
704 	struct se_device *dev = container_of(work, struct se_device,
705 					qf_work_queue);
706 	LIST_HEAD(qf_cmd_list);
707 	struct se_cmd *cmd, *cmd_tmp;
708 
709 	spin_lock_irq(&dev->qf_cmd_lock);
710 	list_splice_init(&dev->qf_cmd_list, &qf_cmd_list);
711 	spin_unlock_irq(&dev->qf_cmd_lock);
712 
713 	list_for_each_entry_safe(cmd, cmd_tmp, &qf_cmd_list, se_qf_node) {
714 		list_del(&cmd->se_qf_node);
715 		atomic_dec(&dev->dev_qf_count);
716 		smp_mb__after_atomic_dec();
717 
718 		pr_debug("Processing %s cmd: %p QUEUE_FULL in work queue"
719 			" context: %s\n", cmd->se_tfo->get_fabric_name(), cmd,
720 			(cmd->t_state == TRANSPORT_COMPLETE_QF_OK) ? "COMPLETE_OK" :
721 			(cmd->t_state == TRANSPORT_COMPLETE_QF_WP) ? "WRITE_PENDING"
722 			: "UNKNOWN");
723 
724 		if (cmd->t_state == TRANSPORT_COMPLETE_QF_WP)
725 			transport_write_pending_qf(cmd);
726 		else if (cmd->t_state == TRANSPORT_COMPLETE_QF_OK)
727 			transport_complete_qf(cmd);
728 	}
729 }
730 
731 unsigned char *transport_dump_cmd_direction(struct se_cmd *cmd)
732 {
733 	switch (cmd->data_direction) {
734 	case DMA_NONE:
735 		return "NONE";
736 	case DMA_FROM_DEVICE:
737 		return "READ";
738 	case DMA_TO_DEVICE:
739 		return "WRITE";
740 	case DMA_BIDIRECTIONAL:
741 		return "BIDI";
742 	default:
743 		break;
744 	}
745 
746 	return "UNKNOWN";
747 }
748 
749 void transport_dump_dev_state(
750 	struct se_device *dev,
751 	char *b,
752 	int *bl)
753 {
754 	*bl += sprintf(b + *bl, "Status: ");
755 	if (dev->export_count)
756 		*bl += sprintf(b + *bl, "ACTIVATED");
757 	else
758 		*bl += sprintf(b + *bl, "DEACTIVATED");
759 
760 	*bl += sprintf(b + *bl, "  Max Queue Depth: %d", dev->queue_depth);
761 	*bl += sprintf(b + *bl, "  SectorSize: %u  HwMaxSectors: %u\n",
762 		dev->dev_attrib.block_size,
763 		dev->dev_attrib.hw_max_sectors);
764 	*bl += sprintf(b + *bl, "        ");
765 }
766 
767 void transport_dump_vpd_proto_id(
768 	struct t10_vpd *vpd,
769 	unsigned char *p_buf,
770 	int p_buf_len)
771 {
772 	unsigned char buf[VPD_TMP_BUF_SIZE];
773 	int len;
774 
775 	memset(buf, 0, VPD_TMP_BUF_SIZE);
776 	len = sprintf(buf, "T10 VPD Protocol Identifier: ");
777 
778 	switch (vpd->protocol_identifier) {
779 	case 0x00:
780 		sprintf(buf+len, "Fibre Channel\n");
781 		break;
782 	case 0x10:
783 		sprintf(buf+len, "Parallel SCSI\n");
784 		break;
785 	case 0x20:
786 		sprintf(buf+len, "SSA\n");
787 		break;
788 	case 0x30:
789 		sprintf(buf+len, "IEEE 1394\n");
790 		break;
791 	case 0x40:
792 		sprintf(buf+len, "SCSI Remote Direct Memory Access"
793 				" Protocol\n");
794 		break;
795 	case 0x50:
796 		sprintf(buf+len, "Internet SCSI (iSCSI)\n");
797 		break;
798 	case 0x60:
799 		sprintf(buf+len, "SAS Serial SCSI Protocol\n");
800 		break;
801 	case 0x70:
802 		sprintf(buf+len, "Automation/Drive Interface Transport"
803 				" Protocol\n");
804 		break;
805 	case 0x80:
806 		sprintf(buf+len, "AT Attachment Interface ATA/ATAPI\n");
807 		break;
808 	default:
809 		sprintf(buf+len, "Unknown 0x%02x\n",
810 				vpd->protocol_identifier);
811 		break;
812 	}
813 
814 	if (p_buf)
815 		strncpy(p_buf, buf, p_buf_len);
816 	else
817 		pr_debug("%s", buf);
818 }
819 
820 void
821 transport_set_vpd_proto_id(struct t10_vpd *vpd, unsigned char *page_83)
822 {
823 	/*
824 	 * Check if the Protocol Identifier Valid (PIV) bit is set..
825 	 *
826 	 * from spc3r23.pdf section 7.5.1
827 	 */
828 	 if (page_83[1] & 0x80) {
829 		vpd->protocol_identifier = (page_83[0] & 0xf0);
830 		vpd->protocol_identifier_set = 1;
831 		transport_dump_vpd_proto_id(vpd, NULL, 0);
832 	}
833 }
834 EXPORT_SYMBOL(transport_set_vpd_proto_id);
835 
836 int transport_dump_vpd_assoc(
837 	struct t10_vpd *vpd,
838 	unsigned char *p_buf,
839 	int p_buf_len)
840 {
841 	unsigned char buf[VPD_TMP_BUF_SIZE];
842 	int ret = 0;
843 	int len;
844 
845 	memset(buf, 0, VPD_TMP_BUF_SIZE);
846 	len = sprintf(buf, "T10 VPD Identifier Association: ");
847 
848 	switch (vpd->association) {
849 	case 0x00:
850 		sprintf(buf+len, "addressed logical unit\n");
851 		break;
852 	case 0x10:
853 		sprintf(buf+len, "target port\n");
854 		break;
855 	case 0x20:
856 		sprintf(buf+len, "SCSI target device\n");
857 		break;
858 	default:
859 		sprintf(buf+len, "Unknown 0x%02x\n", vpd->association);
860 		ret = -EINVAL;
861 		break;
862 	}
863 
864 	if (p_buf)
865 		strncpy(p_buf, buf, p_buf_len);
866 	else
867 		pr_debug("%s", buf);
868 
869 	return ret;
870 }
871 
872 int transport_set_vpd_assoc(struct t10_vpd *vpd, unsigned char *page_83)
873 {
874 	/*
875 	 * The VPD identification association..
876 	 *
877 	 * from spc3r23.pdf Section 7.6.3.1 Table 297
878 	 */
879 	vpd->association = (page_83[1] & 0x30);
880 	return transport_dump_vpd_assoc(vpd, NULL, 0);
881 }
882 EXPORT_SYMBOL(transport_set_vpd_assoc);
883 
884 int transport_dump_vpd_ident_type(
885 	struct t10_vpd *vpd,
886 	unsigned char *p_buf,
887 	int p_buf_len)
888 {
889 	unsigned char buf[VPD_TMP_BUF_SIZE];
890 	int ret = 0;
891 	int len;
892 
893 	memset(buf, 0, VPD_TMP_BUF_SIZE);
894 	len = sprintf(buf, "T10 VPD Identifier Type: ");
895 
896 	switch (vpd->device_identifier_type) {
897 	case 0x00:
898 		sprintf(buf+len, "Vendor specific\n");
899 		break;
900 	case 0x01:
901 		sprintf(buf+len, "T10 Vendor ID based\n");
902 		break;
903 	case 0x02:
904 		sprintf(buf+len, "EUI-64 based\n");
905 		break;
906 	case 0x03:
907 		sprintf(buf+len, "NAA\n");
908 		break;
909 	case 0x04:
910 		sprintf(buf+len, "Relative target port identifier\n");
911 		break;
912 	case 0x08:
913 		sprintf(buf+len, "SCSI name string\n");
914 		break;
915 	default:
916 		sprintf(buf+len, "Unsupported: 0x%02x\n",
917 				vpd->device_identifier_type);
918 		ret = -EINVAL;
919 		break;
920 	}
921 
922 	if (p_buf) {
923 		if (p_buf_len < strlen(buf)+1)
924 			return -EINVAL;
925 		strncpy(p_buf, buf, p_buf_len);
926 	} else {
927 		pr_debug("%s", buf);
928 	}
929 
930 	return ret;
931 }
932 
933 int transport_set_vpd_ident_type(struct t10_vpd *vpd, unsigned char *page_83)
934 {
935 	/*
936 	 * The VPD identifier type..
937 	 *
938 	 * from spc3r23.pdf Section 7.6.3.1 Table 298
939 	 */
940 	vpd->device_identifier_type = (page_83[1] & 0x0f);
941 	return transport_dump_vpd_ident_type(vpd, NULL, 0);
942 }
943 EXPORT_SYMBOL(transport_set_vpd_ident_type);
944 
945 int transport_dump_vpd_ident(
946 	struct t10_vpd *vpd,
947 	unsigned char *p_buf,
948 	int p_buf_len)
949 {
950 	unsigned char buf[VPD_TMP_BUF_SIZE];
951 	int ret = 0;
952 
953 	memset(buf, 0, VPD_TMP_BUF_SIZE);
954 
955 	switch (vpd->device_identifier_code_set) {
956 	case 0x01: /* Binary */
957 		snprintf(buf, sizeof(buf),
958 			"T10 VPD Binary Device Identifier: %s\n",
959 			&vpd->device_identifier[0]);
960 		break;
961 	case 0x02: /* ASCII */
962 		snprintf(buf, sizeof(buf),
963 			"T10 VPD ASCII Device Identifier: %s\n",
964 			&vpd->device_identifier[0]);
965 		break;
966 	case 0x03: /* UTF-8 */
967 		snprintf(buf, sizeof(buf),
968 			"T10 VPD UTF-8 Device Identifier: %s\n",
969 			&vpd->device_identifier[0]);
970 		break;
971 	default:
972 		sprintf(buf, "T10 VPD Device Identifier encoding unsupported:"
973 			" 0x%02x", vpd->device_identifier_code_set);
974 		ret = -EINVAL;
975 		break;
976 	}
977 
978 	if (p_buf)
979 		strncpy(p_buf, buf, p_buf_len);
980 	else
981 		pr_debug("%s", buf);
982 
983 	return ret;
984 }
985 
986 int
987 transport_set_vpd_ident(struct t10_vpd *vpd, unsigned char *page_83)
988 {
989 	static const char hex_str[] = "0123456789abcdef";
990 	int j = 0, i = 4; /* offset to start of the identifier */
991 
992 	/*
993 	 * The VPD Code Set (encoding)
994 	 *
995 	 * from spc3r23.pdf Section 7.6.3.1 Table 296
996 	 */
997 	vpd->device_identifier_code_set = (page_83[0] & 0x0f);
998 	switch (vpd->device_identifier_code_set) {
999 	case 0x01: /* Binary */
1000 		vpd->device_identifier[j++] =
1001 				hex_str[vpd->device_identifier_type];
1002 		while (i < (4 + page_83[3])) {
1003 			vpd->device_identifier[j++] =
1004 				hex_str[(page_83[i] & 0xf0) >> 4];
1005 			vpd->device_identifier[j++] =
1006 				hex_str[page_83[i] & 0x0f];
1007 			i++;
1008 		}
1009 		break;
1010 	case 0x02: /* ASCII */
1011 	case 0x03: /* UTF-8 */
1012 		while (i < (4 + page_83[3]))
1013 			vpd->device_identifier[j++] = page_83[i++];
1014 		break;
1015 	default:
1016 		break;
1017 	}
1018 
1019 	return transport_dump_vpd_ident(vpd, NULL, 0);
1020 }
1021 EXPORT_SYMBOL(transport_set_vpd_ident);
1022 
1023 sense_reason_t
1024 target_cmd_size_check(struct se_cmd *cmd, unsigned int size)
1025 {
1026 	struct se_device *dev = cmd->se_dev;
1027 
1028 	if (cmd->unknown_data_length) {
1029 		cmd->data_length = size;
1030 	} else if (size != cmd->data_length) {
1031 		pr_warn("TARGET_CORE[%s]: Expected Transfer Length:"
1032 			" %u does not match SCSI CDB Length: %u for SAM Opcode:"
1033 			" 0x%02x\n", cmd->se_tfo->get_fabric_name(),
1034 				cmd->data_length, size, cmd->t_task_cdb[0]);
1035 
1036 		if (cmd->data_direction == DMA_TO_DEVICE) {
1037 			pr_err("Rejecting underflow/overflow"
1038 					" WRITE data\n");
1039 			return TCM_INVALID_CDB_FIELD;
1040 		}
1041 		/*
1042 		 * Reject READ_* or WRITE_* with overflow/underflow for
1043 		 * type SCF_SCSI_DATA_CDB.
1044 		 */
1045 		if (dev->dev_attrib.block_size != 512)  {
1046 			pr_err("Failing OVERFLOW/UNDERFLOW for LBA op"
1047 				" CDB on non 512-byte sector setup subsystem"
1048 				" plugin: %s\n", dev->transport->name);
1049 			/* Returns CHECK_CONDITION + INVALID_CDB_FIELD */
1050 			return TCM_INVALID_CDB_FIELD;
1051 		}
1052 		/*
1053 		 * For the overflow case keep the existing fabric provided
1054 		 * ->data_length.  Otherwise for the underflow case, reset
1055 		 * ->data_length to the smaller SCSI expected data transfer
1056 		 * length.
1057 		 */
1058 		if (size > cmd->data_length) {
1059 			cmd->se_cmd_flags |= SCF_OVERFLOW_BIT;
1060 			cmd->residual_count = (size - cmd->data_length);
1061 		} else {
1062 			cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
1063 			cmd->residual_count = (cmd->data_length - size);
1064 			cmd->data_length = size;
1065 		}
1066 	}
1067 
1068 	return 0;
1069 
1070 }
1071 
1072 /*
1073  * Used by fabric modules containing a local struct se_cmd within their
1074  * fabric dependent per I/O descriptor.
1075  */
1076 void transport_init_se_cmd(
1077 	struct se_cmd *cmd,
1078 	struct target_core_fabric_ops *tfo,
1079 	struct se_session *se_sess,
1080 	u32 data_length,
1081 	int data_direction,
1082 	int task_attr,
1083 	unsigned char *sense_buffer)
1084 {
1085 	INIT_LIST_HEAD(&cmd->se_lun_node);
1086 	INIT_LIST_HEAD(&cmd->se_delayed_node);
1087 	INIT_LIST_HEAD(&cmd->se_qf_node);
1088 	INIT_LIST_HEAD(&cmd->se_cmd_list);
1089 	INIT_LIST_HEAD(&cmd->state_list);
1090 	init_completion(&cmd->transport_lun_fe_stop_comp);
1091 	init_completion(&cmd->transport_lun_stop_comp);
1092 	init_completion(&cmd->t_transport_stop_comp);
1093 	init_completion(&cmd->cmd_wait_comp);
1094 	init_completion(&cmd->task_stop_comp);
1095 	spin_lock_init(&cmd->t_state_lock);
1096 	cmd->transport_state = CMD_T_DEV_ACTIVE;
1097 
1098 	cmd->se_tfo = tfo;
1099 	cmd->se_sess = se_sess;
1100 	cmd->data_length = data_length;
1101 	cmd->data_direction = data_direction;
1102 	cmd->sam_task_attr = task_attr;
1103 	cmd->sense_buffer = sense_buffer;
1104 
1105 	cmd->state_active = false;
1106 }
1107 EXPORT_SYMBOL(transport_init_se_cmd);
1108 
1109 static sense_reason_t
1110 transport_check_alloc_task_attr(struct se_cmd *cmd)
1111 {
1112 	struct se_device *dev = cmd->se_dev;
1113 
1114 	/*
1115 	 * Check if SAM Task Attribute emulation is enabled for this
1116 	 * struct se_device storage object
1117 	 */
1118 	if (dev->transport->transport_type == TRANSPORT_PLUGIN_PHBA_PDEV)
1119 		return 0;
1120 
1121 	if (cmd->sam_task_attr == MSG_ACA_TAG) {
1122 		pr_debug("SAM Task Attribute ACA"
1123 			" emulation is not supported\n");
1124 		return TCM_INVALID_CDB_FIELD;
1125 	}
1126 	/*
1127 	 * Used to determine when ORDERED commands should go from
1128 	 * Dormant to Active status.
1129 	 */
1130 	cmd->se_ordered_id = atomic_inc_return(&dev->dev_ordered_id);
1131 	smp_mb__after_atomic_inc();
1132 	pr_debug("Allocated se_ordered_id: %u for Task Attr: 0x%02x on %s\n",
1133 			cmd->se_ordered_id, cmd->sam_task_attr,
1134 			dev->transport->name);
1135 	return 0;
1136 }
1137 
1138 sense_reason_t
1139 target_setup_cmd_from_cdb(struct se_cmd *cmd, unsigned char *cdb)
1140 {
1141 	struct se_device *dev = cmd->se_dev;
1142 	sense_reason_t ret;
1143 
1144 	/*
1145 	 * Ensure that the received CDB is less than the max (252 + 8) bytes
1146 	 * for VARIABLE_LENGTH_CMD
1147 	 */
1148 	if (scsi_command_size(cdb) > SCSI_MAX_VARLEN_CDB_SIZE) {
1149 		pr_err("Received SCSI CDB with command_size: %d that"
1150 			" exceeds SCSI_MAX_VARLEN_CDB_SIZE: %d\n",
1151 			scsi_command_size(cdb), SCSI_MAX_VARLEN_CDB_SIZE);
1152 		return TCM_INVALID_CDB_FIELD;
1153 	}
1154 	/*
1155 	 * If the received CDB is larger than TCM_MAX_COMMAND_SIZE,
1156 	 * allocate the additional extended CDB buffer now..  Otherwise
1157 	 * setup the pointer from __t_task_cdb to t_task_cdb.
1158 	 */
1159 	if (scsi_command_size(cdb) > sizeof(cmd->__t_task_cdb)) {
1160 		cmd->t_task_cdb = kzalloc(scsi_command_size(cdb),
1161 						GFP_KERNEL);
1162 		if (!cmd->t_task_cdb) {
1163 			pr_err("Unable to allocate cmd->t_task_cdb"
1164 				" %u > sizeof(cmd->__t_task_cdb): %lu ops\n",
1165 				scsi_command_size(cdb),
1166 				(unsigned long)sizeof(cmd->__t_task_cdb));
1167 			return TCM_OUT_OF_RESOURCES;
1168 		}
1169 	} else
1170 		cmd->t_task_cdb = &cmd->__t_task_cdb[0];
1171 	/*
1172 	 * Copy the original CDB into cmd->
1173 	 */
1174 	memcpy(cmd->t_task_cdb, cdb, scsi_command_size(cdb));
1175 
1176 	trace_target_sequencer_start(cmd);
1177 
1178 	/*
1179 	 * Check for an existing UNIT ATTENTION condition
1180 	 */
1181 	ret = target_scsi3_ua_check(cmd);
1182 	if (ret)
1183 		return ret;
1184 
1185 	ret = target_alua_state_check(cmd);
1186 	if (ret)
1187 		return ret;
1188 
1189 	ret = target_check_reservation(cmd);
1190 	if (ret) {
1191 		cmd->scsi_status = SAM_STAT_RESERVATION_CONFLICT;
1192 		return ret;
1193 	}
1194 
1195 	ret = dev->transport->parse_cdb(cmd);
1196 	if (ret)
1197 		return ret;
1198 
1199 	ret = transport_check_alloc_task_attr(cmd);
1200 	if (ret)
1201 		return ret;
1202 
1203 	cmd->se_cmd_flags |= SCF_SUPPORTED_SAM_OPCODE;
1204 
1205 	spin_lock(&cmd->se_lun->lun_sep_lock);
1206 	if (cmd->se_lun->lun_sep)
1207 		cmd->se_lun->lun_sep->sep_stats.cmd_pdus++;
1208 	spin_unlock(&cmd->se_lun->lun_sep_lock);
1209 	return 0;
1210 }
1211 EXPORT_SYMBOL(target_setup_cmd_from_cdb);
1212 
1213 /*
1214  * Used by fabric module frontends to queue tasks directly.
1215  * Many only be used from process context only
1216  */
1217 int transport_handle_cdb_direct(
1218 	struct se_cmd *cmd)
1219 {
1220 	sense_reason_t ret;
1221 
1222 	if (!cmd->se_lun) {
1223 		dump_stack();
1224 		pr_err("cmd->se_lun is NULL\n");
1225 		return -EINVAL;
1226 	}
1227 	if (in_interrupt()) {
1228 		dump_stack();
1229 		pr_err("transport_generic_handle_cdb cannot be called"
1230 				" from interrupt context\n");
1231 		return -EINVAL;
1232 	}
1233 	/*
1234 	 * Set TRANSPORT_NEW_CMD state and CMD_T_ACTIVE to ensure that
1235 	 * outstanding descriptors are handled correctly during shutdown via
1236 	 * transport_wait_for_tasks()
1237 	 *
1238 	 * Also, we don't take cmd->t_state_lock here as we only expect
1239 	 * this to be called for initial descriptor submission.
1240 	 */
1241 	cmd->t_state = TRANSPORT_NEW_CMD;
1242 	cmd->transport_state |= CMD_T_ACTIVE;
1243 
1244 	/*
1245 	 * transport_generic_new_cmd() is already handling QUEUE_FULL,
1246 	 * so follow TRANSPORT_NEW_CMD processing thread context usage
1247 	 * and call transport_generic_request_failure() if necessary..
1248 	 */
1249 	ret = transport_generic_new_cmd(cmd);
1250 	if (ret)
1251 		transport_generic_request_failure(cmd, ret);
1252 	return 0;
1253 }
1254 EXPORT_SYMBOL(transport_handle_cdb_direct);
1255 
1256 sense_reason_t
1257 transport_generic_map_mem_to_cmd(struct se_cmd *cmd, struct scatterlist *sgl,
1258 		u32 sgl_count, struct scatterlist *sgl_bidi, u32 sgl_bidi_count)
1259 {
1260 	if (!sgl || !sgl_count)
1261 		return 0;
1262 
1263 	/*
1264 	 * Reject SCSI data overflow with map_mem_to_cmd() as incoming
1265 	 * scatterlists already have been set to follow what the fabric
1266 	 * passes for the original expected data transfer length.
1267 	 */
1268 	if (cmd->se_cmd_flags & SCF_OVERFLOW_BIT) {
1269 		pr_warn("Rejecting SCSI DATA overflow for fabric using"
1270 			" SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC\n");
1271 		return TCM_INVALID_CDB_FIELD;
1272 	}
1273 
1274 	cmd->t_data_sg = sgl;
1275 	cmd->t_data_nents = sgl_count;
1276 
1277 	if (sgl_bidi && sgl_bidi_count) {
1278 		cmd->t_bidi_data_sg = sgl_bidi;
1279 		cmd->t_bidi_data_nents = sgl_bidi_count;
1280 	}
1281 	cmd->se_cmd_flags |= SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC;
1282 	return 0;
1283 }
1284 
1285 /*
1286  * target_submit_cmd_map_sgls - lookup unpacked lun and submit uninitialized
1287  * 			 se_cmd + use pre-allocated SGL memory.
1288  *
1289  * @se_cmd: command descriptor to submit
1290  * @se_sess: associated se_sess for endpoint
1291  * @cdb: pointer to SCSI CDB
1292  * @sense: pointer to SCSI sense buffer
1293  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1294  * @data_length: fabric expected data transfer length
1295  * @task_addr: SAM task attribute
1296  * @data_dir: DMA data direction
1297  * @flags: flags for command submission from target_sc_flags_tables
1298  * @sgl: struct scatterlist memory for unidirectional mapping
1299  * @sgl_count: scatterlist count for unidirectional mapping
1300  * @sgl_bidi: struct scatterlist memory for bidirectional READ mapping
1301  * @sgl_bidi_count: scatterlist count for bidirectional READ mapping
1302  *
1303  * Returns non zero to signal active I/O shutdown failure.  All other
1304  * setup exceptions will be returned as a SCSI CHECK_CONDITION response,
1305  * but still return zero here.
1306  *
1307  * This may only be called from process context, and also currently
1308  * assumes internal allocation of fabric payload buffer by target-core.
1309  */
1310 int target_submit_cmd_map_sgls(struct se_cmd *se_cmd, struct se_session *se_sess,
1311 		unsigned char *cdb, unsigned char *sense, u32 unpacked_lun,
1312 		u32 data_length, int task_attr, int data_dir, int flags,
1313 		struct scatterlist *sgl, u32 sgl_count,
1314 		struct scatterlist *sgl_bidi, u32 sgl_bidi_count)
1315 {
1316 	struct se_portal_group *se_tpg;
1317 	sense_reason_t rc;
1318 	int ret;
1319 
1320 	se_tpg = se_sess->se_tpg;
1321 	BUG_ON(!se_tpg);
1322 	BUG_ON(se_cmd->se_tfo || se_cmd->se_sess);
1323 	BUG_ON(in_interrupt());
1324 	/*
1325 	 * Initialize se_cmd for target operation.  From this point
1326 	 * exceptions are handled by sending exception status via
1327 	 * target_core_fabric_ops->queue_status() callback
1328 	 */
1329 	transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess,
1330 				data_length, data_dir, task_attr, sense);
1331 	if (flags & TARGET_SCF_UNKNOWN_SIZE)
1332 		se_cmd->unknown_data_length = 1;
1333 	/*
1334 	 * Obtain struct se_cmd->cmd_kref reference and add new cmd to
1335 	 * se_sess->sess_cmd_list.  A second kref_get here is necessary
1336 	 * for fabrics using TARGET_SCF_ACK_KREF that expect a second
1337 	 * kref_put() to happen during fabric packet acknowledgement.
1338 	 */
1339 	ret = target_get_sess_cmd(se_sess, se_cmd, (flags & TARGET_SCF_ACK_KREF));
1340 	if (ret)
1341 		return ret;
1342 	/*
1343 	 * Signal bidirectional data payloads to target-core
1344 	 */
1345 	if (flags & TARGET_SCF_BIDI_OP)
1346 		se_cmd->se_cmd_flags |= SCF_BIDI;
1347 	/*
1348 	 * Locate se_lun pointer and attach it to struct se_cmd
1349 	 */
1350 	rc = transport_lookup_cmd_lun(se_cmd, unpacked_lun);
1351 	if (rc) {
1352 		transport_send_check_condition_and_sense(se_cmd, rc, 0);
1353 		target_put_sess_cmd(se_sess, se_cmd);
1354 		return 0;
1355 	}
1356 
1357 	rc = target_setup_cmd_from_cdb(se_cmd, cdb);
1358 	if (rc != 0) {
1359 		transport_generic_request_failure(se_cmd, rc);
1360 		return 0;
1361 	}
1362 	/*
1363 	 * When a non zero sgl_count has been passed perform SGL passthrough
1364 	 * mapping for pre-allocated fabric memory instead of having target
1365 	 * core perform an internal SGL allocation..
1366 	 */
1367 	if (sgl_count != 0) {
1368 		BUG_ON(!sgl);
1369 
1370 		/*
1371 		 * A work-around for tcm_loop as some userspace code via
1372 		 * scsi-generic do not memset their associated read buffers,
1373 		 * so go ahead and do that here for type non-data CDBs.  Also
1374 		 * note that this is currently guaranteed to be a single SGL
1375 		 * for this case by target core in target_setup_cmd_from_cdb()
1376 		 * -> transport_generic_cmd_sequencer().
1377 		 */
1378 		if (!(se_cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) &&
1379 		     se_cmd->data_direction == DMA_FROM_DEVICE) {
1380 			unsigned char *buf = NULL;
1381 
1382 			if (sgl)
1383 				buf = kmap(sg_page(sgl)) + sgl->offset;
1384 
1385 			if (buf) {
1386 				memset(buf, 0, sgl->length);
1387 				kunmap(sg_page(sgl));
1388 			}
1389 		}
1390 
1391 		rc = transport_generic_map_mem_to_cmd(se_cmd, sgl, sgl_count,
1392 				sgl_bidi, sgl_bidi_count);
1393 		if (rc != 0) {
1394 			transport_generic_request_failure(se_cmd, rc);
1395 			return 0;
1396 		}
1397 	}
1398 	/*
1399 	 * Check if we need to delay processing because of ALUA
1400 	 * Active/NonOptimized primary access state..
1401 	 */
1402 	core_alua_check_nonop_delay(se_cmd);
1403 
1404 	transport_handle_cdb_direct(se_cmd);
1405 	return 0;
1406 }
1407 EXPORT_SYMBOL(target_submit_cmd_map_sgls);
1408 
1409 /*
1410  * target_submit_cmd - lookup unpacked lun and submit uninitialized se_cmd
1411  *
1412  * @se_cmd: command descriptor to submit
1413  * @se_sess: associated se_sess for endpoint
1414  * @cdb: pointer to SCSI CDB
1415  * @sense: pointer to SCSI sense buffer
1416  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1417  * @data_length: fabric expected data transfer length
1418  * @task_addr: SAM task attribute
1419  * @data_dir: DMA data direction
1420  * @flags: flags for command submission from target_sc_flags_tables
1421  *
1422  * Returns non zero to signal active I/O shutdown failure.  All other
1423  * setup exceptions will be returned as a SCSI CHECK_CONDITION response,
1424  * but still return zero here.
1425  *
1426  * This may only be called from process context, and also currently
1427  * assumes internal allocation of fabric payload buffer by target-core.
1428  *
1429  * It also assumes interal target core SGL memory allocation.
1430  */
1431 int target_submit_cmd(struct se_cmd *se_cmd, struct se_session *se_sess,
1432 		unsigned char *cdb, unsigned char *sense, u32 unpacked_lun,
1433 		u32 data_length, int task_attr, int data_dir, int flags)
1434 {
1435 	return target_submit_cmd_map_sgls(se_cmd, se_sess, cdb, sense,
1436 			unpacked_lun, data_length, task_attr, data_dir,
1437 			flags, NULL, 0, NULL, 0);
1438 }
1439 EXPORT_SYMBOL(target_submit_cmd);
1440 
1441 static void target_complete_tmr_failure(struct work_struct *work)
1442 {
1443 	struct se_cmd *se_cmd = container_of(work, struct se_cmd, work);
1444 
1445 	se_cmd->se_tmr_req->response = TMR_LUN_DOES_NOT_EXIST;
1446 	se_cmd->se_tfo->queue_tm_rsp(se_cmd);
1447 
1448 	transport_cmd_check_stop_to_fabric(se_cmd);
1449 }
1450 
1451 /**
1452  * target_submit_tmr - lookup unpacked lun and submit uninitialized se_cmd
1453  *                     for TMR CDBs
1454  *
1455  * @se_cmd: command descriptor to submit
1456  * @se_sess: associated se_sess for endpoint
1457  * @sense: pointer to SCSI sense buffer
1458  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1459  * @fabric_context: fabric context for TMR req
1460  * @tm_type: Type of TM request
1461  * @gfp: gfp type for caller
1462  * @tag: referenced task tag for TMR_ABORT_TASK
1463  * @flags: submit cmd flags
1464  *
1465  * Callable from all contexts.
1466  **/
1467 
1468 int target_submit_tmr(struct se_cmd *se_cmd, struct se_session *se_sess,
1469 		unsigned char *sense, u32 unpacked_lun,
1470 		void *fabric_tmr_ptr, unsigned char tm_type,
1471 		gfp_t gfp, unsigned int tag, int flags)
1472 {
1473 	struct se_portal_group *se_tpg;
1474 	int ret;
1475 
1476 	se_tpg = se_sess->se_tpg;
1477 	BUG_ON(!se_tpg);
1478 
1479 	transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess,
1480 			      0, DMA_NONE, MSG_SIMPLE_TAG, sense);
1481 	/*
1482 	 * FIXME: Currently expect caller to handle se_cmd->se_tmr_req
1483 	 * allocation failure.
1484 	 */
1485 	ret = core_tmr_alloc_req(se_cmd, fabric_tmr_ptr, tm_type, gfp);
1486 	if (ret < 0)
1487 		return -ENOMEM;
1488 
1489 	if (tm_type == TMR_ABORT_TASK)
1490 		se_cmd->se_tmr_req->ref_task_tag = tag;
1491 
1492 	/* See target_submit_cmd for commentary */
1493 	ret = target_get_sess_cmd(se_sess, se_cmd, (flags & TARGET_SCF_ACK_KREF));
1494 	if (ret) {
1495 		core_tmr_release_req(se_cmd->se_tmr_req);
1496 		return ret;
1497 	}
1498 
1499 	ret = transport_lookup_tmr_lun(se_cmd, unpacked_lun);
1500 	if (ret) {
1501 		/*
1502 		 * For callback during failure handling, push this work off
1503 		 * to process context with TMR_LUN_DOES_NOT_EXIST status.
1504 		 */
1505 		INIT_WORK(&se_cmd->work, target_complete_tmr_failure);
1506 		schedule_work(&se_cmd->work);
1507 		return 0;
1508 	}
1509 	transport_generic_handle_tmr(se_cmd);
1510 	return 0;
1511 }
1512 EXPORT_SYMBOL(target_submit_tmr);
1513 
1514 /*
1515  * If the cmd is active, request it to be stopped and sleep until it
1516  * has completed.
1517  */
1518 bool target_stop_cmd(struct se_cmd *cmd, unsigned long *flags)
1519 {
1520 	bool was_active = false;
1521 
1522 	if (cmd->transport_state & CMD_T_BUSY) {
1523 		cmd->transport_state |= CMD_T_REQUEST_STOP;
1524 		spin_unlock_irqrestore(&cmd->t_state_lock, *flags);
1525 
1526 		pr_debug("cmd %p waiting to complete\n", cmd);
1527 		wait_for_completion(&cmd->task_stop_comp);
1528 		pr_debug("cmd %p stopped successfully\n", cmd);
1529 
1530 		spin_lock_irqsave(&cmd->t_state_lock, *flags);
1531 		cmd->transport_state &= ~CMD_T_REQUEST_STOP;
1532 		cmd->transport_state &= ~CMD_T_BUSY;
1533 		was_active = true;
1534 	}
1535 
1536 	return was_active;
1537 }
1538 
1539 /*
1540  * Handle SAM-esque emulation for generic transport request failures.
1541  */
1542 void transport_generic_request_failure(struct se_cmd *cmd,
1543 		sense_reason_t sense_reason)
1544 {
1545 	int ret = 0;
1546 
1547 	pr_debug("-----[ Storage Engine Exception for cmd: %p ITT: 0x%08x"
1548 		" CDB: 0x%02x\n", cmd, cmd->se_tfo->get_task_tag(cmd),
1549 		cmd->t_task_cdb[0]);
1550 	pr_debug("-----[ i_state: %d t_state: %d sense_reason: %d\n",
1551 		cmd->se_tfo->get_cmd_state(cmd),
1552 		cmd->t_state, sense_reason);
1553 	pr_debug("-----[ CMD_T_ACTIVE: %d CMD_T_STOP: %d CMD_T_SENT: %d\n",
1554 		(cmd->transport_state & CMD_T_ACTIVE) != 0,
1555 		(cmd->transport_state & CMD_T_STOP) != 0,
1556 		(cmd->transport_state & CMD_T_SENT) != 0);
1557 
1558 	/*
1559 	 * For SAM Task Attribute emulation for failed struct se_cmd
1560 	 */
1561 	transport_complete_task_attr(cmd);
1562 	/*
1563 	 * Handle special case for COMPARE_AND_WRITE failure, where the
1564 	 * callback is expected to drop the per device ->caw_mutex.
1565 	 */
1566 	if ((cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) &&
1567 	     cmd->transport_complete_callback)
1568 		cmd->transport_complete_callback(cmd);
1569 
1570 	switch (sense_reason) {
1571 	case TCM_NON_EXISTENT_LUN:
1572 	case TCM_UNSUPPORTED_SCSI_OPCODE:
1573 	case TCM_INVALID_CDB_FIELD:
1574 	case TCM_INVALID_PARAMETER_LIST:
1575 	case TCM_PARAMETER_LIST_LENGTH_ERROR:
1576 	case TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE:
1577 	case TCM_UNKNOWN_MODE_PAGE:
1578 	case TCM_WRITE_PROTECTED:
1579 	case TCM_ADDRESS_OUT_OF_RANGE:
1580 	case TCM_CHECK_CONDITION_ABORT_CMD:
1581 	case TCM_CHECK_CONDITION_UNIT_ATTENTION:
1582 	case TCM_CHECK_CONDITION_NOT_READY:
1583 		break;
1584 	case TCM_OUT_OF_RESOURCES:
1585 		sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
1586 		break;
1587 	case TCM_RESERVATION_CONFLICT:
1588 		/*
1589 		 * No SENSE Data payload for this case, set SCSI Status
1590 		 * and queue the response to $FABRIC_MOD.
1591 		 *
1592 		 * Uses linux/include/scsi/scsi.h SAM status codes defs
1593 		 */
1594 		cmd->scsi_status = SAM_STAT_RESERVATION_CONFLICT;
1595 		/*
1596 		 * For UA Interlock Code 11b, a RESERVATION CONFLICT will
1597 		 * establish a UNIT ATTENTION with PREVIOUS RESERVATION
1598 		 * CONFLICT STATUS.
1599 		 *
1600 		 * See spc4r17, section 7.4.6 Control Mode Page, Table 349
1601 		 */
1602 		if (cmd->se_sess &&
1603 		    cmd->se_dev->dev_attrib.emulate_ua_intlck_ctrl == 2)
1604 			core_scsi3_ua_allocate(cmd->se_sess->se_node_acl,
1605 				cmd->orig_fe_lun, 0x2C,
1606 				ASCQ_2CH_PREVIOUS_RESERVATION_CONFLICT_STATUS);
1607 
1608 		trace_target_cmd_complete(cmd);
1609 		ret = cmd->se_tfo-> queue_status(cmd);
1610 		if (ret == -EAGAIN || ret == -ENOMEM)
1611 			goto queue_full;
1612 		goto check_stop;
1613 	default:
1614 		pr_err("Unknown transport error for CDB 0x%02x: %d\n",
1615 			cmd->t_task_cdb[0], sense_reason);
1616 		sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
1617 		break;
1618 	}
1619 
1620 	ret = transport_send_check_condition_and_sense(cmd, sense_reason, 0);
1621 	if (ret == -EAGAIN || ret == -ENOMEM)
1622 		goto queue_full;
1623 
1624 check_stop:
1625 	transport_lun_remove_cmd(cmd);
1626 	if (!transport_cmd_check_stop_to_fabric(cmd))
1627 		;
1628 	return;
1629 
1630 queue_full:
1631 	cmd->t_state = TRANSPORT_COMPLETE_QF_OK;
1632 	transport_handle_queue_full(cmd, cmd->se_dev);
1633 }
1634 EXPORT_SYMBOL(transport_generic_request_failure);
1635 
1636 void __target_execute_cmd(struct se_cmd *cmd)
1637 {
1638 	sense_reason_t ret;
1639 
1640 	if (cmd->execute_cmd) {
1641 		ret = cmd->execute_cmd(cmd);
1642 		if (ret) {
1643 			spin_lock_irq(&cmd->t_state_lock);
1644 			cmd->transport_state &= ~(CMD_T_BUSY|CMD_T_SENT);
1645 			spin_unlock_irq(&cmd->t_state_lock);
1646 
1647 			transport_generic_request_failure(cmd, ret);
1648 		}
1649 	}
1650 }
1651 
1652 static bool target_handle_task_attr(struct se_cmd *cmd)
1653 {
1654 	struct se_device *dev = cmd->se_dev;
1655 
1656 	if (dev->transport->transport_type == TRANSPORT_PLUGIN_PHBA_PDEV)
1657 		return false;
1658 
1659 	/*
1660 	 * Check for the existence of HEAD_OF_QUEUE, and if true return 1
1661 	 * to allow the passed struct se_cmd list of tasks to the front of the list.
1662 	 */
1663 	switch (cmd->sam_task_attr) {
1664 	case MSG_HEAD_TAG:
1665 		pr_debug("Added HEAD_OF_QUEUE for CDB: 0x%02x, "
1666 			 "se_ordered_id: %u\n",
1667 			 cmd->t_task_cdb[0], cmd->se_ordered_id);
1668 		return false;
1669 	case MSG_ORDERED_TAG:
1670 		atomic_inc(&dev->dev_ordered_sync);
1671 		smp_mb__after_atomic_inc();
1672 
1673 		pr_debug("Added ORDERED for CDB: 0x%02x to ordered list, "
1674 			 " se_ordered_id: %u\n",
1675 			 cmd->t_task_cdb[0], cmd->se_ordered_id);
1676 
1677 		/*
1678 		 * Execute an ORDERED command if no other older commands
1679 		 * exist that need to be completed first.
1680 		 */
1681 		if (!atomic_read(&dev->simple_cmds))
1682 			return false;
1683 		break;
1684 	default:
1685 		/*
1686 		 * For SIMPLE and UNTAGGED Task Attribute commands
1687 		 */
1688 		atomic_inc(&dev->simple_cmds);
1689 		smp_mb__after_atomic_inc();
1690 		break;
1691 	}
1692 
1693 	if (atomic_read(&dev->dev_ordered_sync) == 0)
1694 		return false;
1695 
1696 	spin_lock(&dev->delayed_cmd_lock);
1697 	list_add_tail(&cmd->se_delayed_node, &dev->delayed_cmd_list);
1698 	spin_unlock(&dev->delayed_cmd_lock);
1699 
1700 	pr_debug("Added CDB: 0x%02x Task Attr: 0x%02x to"
1701 		" delayed CMD list, se_ordered_id: %u\n",
1702 		cmd->t_task_cdb[0], cmd->sam_task_attr,
1703 		cmd->se_ordered_id);
1704 	return true;
1705 }
1706 
1707 void target_execute_cmd(struct se_cmd *cmd)
1708 {
1709 	/*
1710 	 * If the received CDB has aleady been aborted stop processing it here.
1711 	 */
1712 	if (transport_check_aborted_status(cmd, 1)) {
1713 		complete(&cmd->transport_lun_stop_comp);
1714 		return;
1715 	}
1716 
1717 	/*
1718 	 * Determine if IOCTL context caller in requesting the stopping of this
1719 	 * command for LUN shutdown purposes.
1720 	 */
1721 	spin_lock_irq(&cmd->t_state_lock);
1722 	if (cmd->transport_state & CMD_T_LUN_STOP) {
1723 		pr_debug("%s:%d CMD_T_LUN_STOP for ITT: 0x%08x\n",
1724 			__func__, __LINE__, cmd->se_tfo->get_task_tag(cmd));
1725 
1726 		cmd->transport_state &= ~CMD_T_ACTIVE;
1727 		spin_unlock_irq(&cmd->t_state_lock);
1728 		complete(&cmd->transport_lun_stop_comp);
1729 		return;
1730 	}
1731 	/*
1732 	 * Determine if frontend context caller is requesting the stopping of
1733 	 * this command for frontend exceptions.
1734 	 */
1735 	if (cmd->transport_state & CMD_T_STOP) {
1736 		pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08x\n",
1737 			__func__, __LINE__,
1738 			cmd->se_tfo->get_task_tag(cmd));
1739 
1740 		spin_unlock_irq(&cmd->t_state_lock);
1741 		complete(&cmd->t_transport_stop_comp);
1742 		return;
1743 	}
1744 
1745 	cmd->t_state = TRANSPORT_PROCESSING;
1746 	cmd->transport_state |= CMD_T_ACTIVE|CMD_T_BUSY|CMD_T_SENT;
1747 	spin_unlock_irq(&cmd->t_state_lock);
1748 
1749 	if (target_handle_task_attr(cmd)) {
1750 		spin_lock_irq(&cmd->t_state_lock);
1751 		cmd->transport_state &= ~CMD_T_BUSY|CMD_T_SENT;
1752 		spin_unlock_irq(&cmd->t_state_lock);
1753 		return;
1754 	}
1755 
1756 	__target_execute_cmd(cmd);
1757 }
1758 EXPORT_SYMBOL(target_execute_cmd);
1759 
1760 /*
1761  * Process all commands up to the last received ORDERED task attribute which
1762  * requires another blocking boundary
1763  */
1764 static void target_restart_delayed_cmds(struct se_device *dev)
1765 {
1766 	for (;;) {
1767 		struct se_cmd *cmd;
1768 
1769 		spin_lock(&dev->delayed_cmd_lock);
1770 		if (list_empty(&dev->delayed_cmd_list)) {
1771 			spin_unlock(&dev->delayed_cmd_lock);
1772 			break;
1773 		}
1774 
1775 		cmd = list_entry(dev->delayed_cmd_list.next,
1776 				 struct se_cmd, se_delayed_node);
1777 		list_del(&cmd->se_delayed_node);
1778 		spin_unlock(&dev->delayed_cmd_lock);
1779 
1780 		__target_execute_cmd(cmd);
1781 
1782 		if (cmd->sam_task_attr == MSG_ORDERED_TAG)
1783 			break;
1784 	}
1785 }
1786 
1787 /*
1788  * Called from I/O completion to determine which dormant/delayed
1789  * and ordered cmds need to have their tasks added to the execution queue.
1790  */
1791 static void transport_complete_task_attr(struct se_cmd *cmd)
1792 {
1793 	struct se_device *dev = cmd->se_dev;
1794 
1795 	if (dev->transport->transport_type == TRANSPORT_PLUGIN_PHBA_PDEV)
1796 		return;
1797 
1798 	if (cmd->sam_task_attr == MSG_SIMPLE_TAG) {
1799 		atomic_dec(&dev->simple_cmds);
1800 		smp_mb__after_atomic_dec();
1801 		dev->dev_cur_ordered_id++;
1802 		pr_debug("Incremented dev->dev_cur_ordered_id: %u for"
1803 			" SIMPLE: %u\n", dev->dev_cur_ordered_id,
1804 			cmd->se_ordered_id);
1805 	} else if (cmd->sam_task_attr == MSG_HEAD_TAG) {
1806 		dev->dev_cur_ordered_id++;
1807 		pr_debug("Incremented dev_cur_ordered_id: %u for"
1808 			" HEAD_OF_QUEUE: %u\n", dev->dev_cur_ordered_id,
1809 			cmd->se_ordered_id);
1810 	} else if (cmd->sam_task_attr == MSG_ORDERED_TAG) {
1811 		atomic_dec(&dev->dev_ordered_sync);
1812 		smp_mb__after_atomic_dec();
1813 
1814 		dev->dev_cur_ordered_id++;
1815 		pr_debug("Incremented dev_cur_ordered_id: %u for ORDERED:"
1816 			" %u\n", dev->dev_cur_ordered_id, cmd->se_ordered_id);
1817 	}
1818 
1819 	target_restart_delayed_cmds(dev);
1820 }
1821 
1822 static void transport_complete_qf(struct se_cmd *cmd)
1823 {
1824 	int ret = 0;
1825 
1826 	transport_complete_task_attr(cmd);
1827 
1828 	if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) {
1829 		trace_target_cmd_complete(cmd);
1830 		ret = cmd->se_tfo->queue_status(cmd);
1831 		if (ret)
1832 			goto out;
1833 	}
1834 
1835 	switch (cmd->data_direction) {
1836 	case DMA_FROM_DEVICE:
1837 		trace_target_cmd_complete(cmd);
1838 		ret = cmd->se_tfo->queue_data_in(cmd);
1839 		break;
1840 	case DMA_TO_DEVICE:
1841 		if (cmd->se_cmd_flags & SCF_BIDI) {
1842 			ret = cmd->se_tfo->queue_data_in(cmd);
1843 			if (ret < 0)
1844 				break;
1845 		}
1846 		/* Fall through for DMA_TO_DEVICE */
1847 	case DMA_NONE:
1848 		trace_target_cmd_complete(cmd);
1849 		ret = cmd->se_tfo->queue_status(cmd);
1850 		break;
1851 	default:
1852 		break;
1853 	}
1854 
1855 out:
1856 	if (ret < 0) {
1857 		transport_handle_queue_full(cmd, cmd->se_dev);
1858 		return;
1859 	}
1860 	transport_lun_remove_cmd(cmd);
1861 	transport_cmd_check_stop_to_fabric(cmd);
1862 }
1863 
1864 static void transport_handle_queue_full(
1865 	struct se_cmd *cmd,
1866 	struct se_device *dev)
1867 {
1868 	spin_lock_irq(&dev->qf_cmd_lock);
1869 	list_add_tail(&cmd->se_qf_node, &cmd->se_dev->qf_cmd_list);
1870 	atomic_inc(&dev->dev_qf_count);
1871 	smp_mb__after_atomic_inc();
1872 	spin_unlock_irq(&cmd->se_dev->qf_cmd_lock);
1873 
1874 	schedule_work(&cmd->se_dev->qf_work_queue);
1875 }
1876 
1877 static void target_complete_ok_work(struct work_struct *work)
1878 {
1879 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
1880 	int ret;
1881 
1882 	/*
1883 	 * Check if we need to move delayed/dormant tasks from cmds on the
1884 	 * delayed execution list after a HEAD_OF_QUEUE or ORDERED Task
1885 	 * Attribute.
1886 	 */
1887 	transport_complete_task_attr(cmd);
1888 
1889 	/*
1890 	 * Check to schedule QUEUE_FULL work, or execute an existing
1891 	 * cmd->transport_qf_callback()
1892 	 */
1893 	if (atomic_read(&cmd->se_dev->dev_qf_count) != 0)
1894 		schedule_work(&cmd->se_dev->qf_work_queue);
1895 
1896 	/*
1897 	 * Check if we need to send a sense buffer from
1898 	 * the struct se_cmd in question.
1899 	 */
1900 	if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) {
1901 		WARN_ON(!cmd->scsi_status);
1902 		ret = transport_send_check_condition_and_sense(
1903 					cmd, 0, 1);
1904 		if (ret == -EAGAIN || ret == -ENOMEM)
1905 			goto queue_full;
1906 
1907 		transport_lun_remove_cmd(cmd);
1908 		transport_cmd_check_stop_to_fabric(cmd);
1909 		return;
1910 	}
1911 	/*
1912 	 * Check for a callback, used by amongst other things
1913 	 * XDWRITE_READ_10 and COMPARE_AND_WRITE emulation.
1914 	 */
1915 	if (cmd->transport_complete_callback) {
1916 		sense_reason_t rc;
1917 
1918 		rc = cmd->transport_complete_callback(cmd);
1919 		if (!rc && !(cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE_POST)) {
1920 			return;
1921 		} else if (rc) {
1922 			ret = transport_send_check_condition_and_sense(cmd,
1923 						rc, 0);
1924 			if (ret == -EAGAIN || ret == -ENOMEM)
1925 				goto queue_full;
1926 
1927 			transport_lun_remove_cmd(cmd);
1928 			transport_cmd_check_stop_to_fabric(cmd);
1929 			return;
1930 		}
1931 	}
1932 
1933 	switch (cmd->data_direction) {
1934 	case DMA_FROM_DEVICE:
1935 		spin_lock(&cmd->se_lun->lun_sep_lock);
1936 		if (cmd->se_lun->lun_sep) {
1937 			cmd->se_lun->lun_sep->sep_stats.tx_data_octets +=
1938 					cmd->data_length;
1939 		}
1940 		spin_unlock(&cmd->se_lun->lun_sep_lock);
1941 
1942 		trace_target_cmd_complete(cmd);
1943 		ret = cmd->se_tfo->queue_data_in(cmd);
1944 		if (ret == -EAGAIN || ret == -ENOMEM)
1945 			goto queue_full;
1946 		break;
1947 	case DMA_TO_DEVICE:
1948 		spin_lock(&cmd->se_lun->lun_sep_lock);
1949 		if (cmd->se_lun->lun_sep) {
1950 			cmd->se_lun->lun_sep->sep_stats.rx_data_octets +=
1951 				cmd->data_length;
1952 		}
1953 		spin_unlock(&cmd->se_lun->lun_sep_lock);
1954 		/*
1955 		 * Check if we need to send READ payload for BIDI-COMMAND
1956 		 */
1957 		if (cmd->se_cmd_flags & SCF_BIDI) {
1958 			spin_lock(&cmd->se_lun->lun_sep_lock);
1959 			if (cmd->se_lun->lun_sep) {
1960 				cmd->se_lun->lun_sep->sep_stats.tx_data_octets +=
1961 					cmd->data_length;
1962 			}
1963 			spin_unlock(&cmd->se_lun->lun_sep_lock);
1964 			ret = cmd->se_tfo->queue_data_in(cmd);
1965 			if (ret == -EAGAIN || ret == -ENOMEM)
1966 				goto queue_full;
1967 			break;
1968 		}
1969 		/* Fall through for DMA_TO_DEVICE */
1970 	case DMA_NONE:
1971 		trace_target_cmd_complete(cmd);
1972 		ret = cmd->se_tfo->queue_status(cmd);
1973 		if (ret == -EAGAIN || ret == -ENOMEM)
1974 			goto queue_full;
1975 		break;
1976 	default:
1977 		break;
1978 	}
1979 
1980 	transport_lun_remove_cmd(cmd);
1981 	transport_cmd_check_stop_to_fabric(cmd);
1982 	return;
1983 
1984 queue_full:
1985 	pr_debug("Handling complete_ok QUEUE_FULL: se_cmd: %p,"
1986 		" data_direction: %d\n", cmd, cmd->data_direction);
1987 	cmd->t_state = TRANSPORT_COMPLETE_QF_OK;
1988 	transport_handle_queue_full(cmd, cmd->se_dev);
1989 }
1990 
1991 static inline void transport_free_sgl(struct scatterlist *sgl, int nents)
1992 {
1993 	struct scatterlist *sg;
1994 	int count;
1995 
1996 	for_each_sg(sgl, sg, nents, count)
1997 		__free_page(sg_page(sg));
1998 
1999 	kfree(sgl);
2000 }
2001 
2002 static inline void transport_reset_sgl_orig(struct se_cmd *cmd)
2003 {
2004 	/*
2005 	 * Check for saved t_data_sg that may be used for COMPARE_AND_WRITE
2006 	 * emulation, and free + reset pointers if necessary..
2007 	 */
2008 	if (!cmd->t_data_sg_orig)
2009 		return;
2010 
2011 	kfree(cmd->t_data_sg);
2012 	cmd->t_data_sg = cmd->t_data_sg_orig;
2013 	cmd->t_data_sg_orig = NULL;
2014 	cmd->t_data_nents = cmd->t_data_nents_orig;
2015 	cmd->t_data_nents_orig = 0;
2016 }
2017 
2018 static inline void transport_free_pages(struct se_cmd *cmd)
2019 {
2020 	if (cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) {
2021 		transport_reset_sgl_orig(cmd);
2022 		return;
2023 	}
2024 	transport_reset_sgl_orig(cmd);
2025 
2026 	transport_free_sgl(cmd->t_data_sg, cmd->t_data_nents);
2027 	cmd->t_data_sg = NULL;
2028 	cmd->t_data_nents = 0;
2029 
2030 	transport_free_sgl(cmd->t_bidi_data_sg, cmd->t_bidi_data_nents);
2031 	cmd->t_bidi_data_sg = NULL;
2032 	cmd->t_bidi_data_nents = 0;
2033 }
2034 
2035 /**
2036  * transport_release_cmd - free a command
2037  * @cmd:       command to free
2038  *
2039  * This routine unconditionally frees a command, and reference counting
2040  * or list removal must be done in the caller.
2041  */
2042 static int transport_release_cmd(struct se_cmd *cmd)
2043 {
2044 	BUG_ON(!cmd->se_tfo);
2045 
2046 	if (cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
2047 		core_tmr_release_req(cmd->se_tmr_req);
2048 	if (cmd->t_task_cdb != cmd->__t_task_cdb)
2049 		kfree(cmd->t_task_cdb);
2050 	/*
2051 	 * If this cmd has been setup with target_get_sess_cmd(), drop
2052 	 * the kref and call ->release_cmd() in kref callback.
2053 	 */
2054 	return target_put_sess_cmd(cmd->se_sess, cmd);
2055 }
2056 
2057 /**
2058  * transport_put_cmd - release a reference to a command
2059  * @cmd:       command to release
2060  *
2061  * This routine releases our reference to the command and frees it if possible.
2062  */
2063 static int transport_put_cmd(struct se_cmd *cmd)
2064 {
2065 	transport_free_pages(cmd);
2066 	return transport_release_cmd(cmd);
2067 }
2068 
2069 void *transport_kmap_data_sg(struct se_cmd *cmd)
2070 {
2071 	struct scatterlist *sg = cmd->t_data_sg;
2072 	struct page **pages;
2073 	int i;
2074 
2075 	/*
2076 	 * We need to take into account a possible offset here for fabrics like
2077 	 * tcm_loop who may be using a contig buffer from the SCSI midlayer for
2078 	 * control CDBs passed as SGLs via transport_generic_map_mem_to_cmd()
2079 	 */
2080 	if (!cmd->t_data_nents)
2081 		return NULL;
2082 
2083 	BUG_ON(!sg);
2084 	if (cmd->t_data_nents == 1)
2085 		return kmap(sg_page(sg)) + sg->offset;
2086 
2087 	/* >1 page. use vmap */
2088 	pages = kmalloc(sizeof(*pages) * cmd->t_data_nents, GFP_KERNEL);
2089 	if (!pages)
2090 		return NULL;
2091 
2092 	/* convert sg[] to pages[] */
2093 	for_each_sg(cmd->t_data_sg, sg, cmd->t_data_nents, i) {
2094 		pages[i] = sg_page(sg);
2095 	}
2096 
2097 	cmd->t_data_vmap = vmap(pages, cmd->t_data_nents,  VM_MAP, PAGE_KERNEL);
2098 	kfree(pages);
2099 	if (!cmd->t_data_vmap)
2100 		return NULL;
2101 
2102 	return cmd->t_data_vmap + cmd->t_data_sg[0].offset;
2103 }
2104 EXPORT_SYMBOL(transport_kmap_data_sg);
2105 
2106 void transport_kunmap_data_sg(struct se_cmd *cmd)
2107 {
2108 	if (!cmd->t_data_nents) {
2109 		return;
2110 	} else if (cmd->t_data_nents == 1) {
2111 		kunmap(sg_page(cmd->t_data_sg));
2112 		return;
2113 	}
2114 
2115 	vunmap(cmd->t_data_vmap);
2116 	cmd->t_data_vmap = NULL;
2117 }
2118 EXPORT_SYMBOL(transport_kunmap_data_sg);
2119 
2120 int
2121 target_alloc_sgl(struct scatterlist **sgl, unsigned int *nents, u32 length,
2122 		 bool zero_page)
2123 {
2124 	struct scatterlist *sg;
2125 	struct page *page;
2126 	gfp_t zero_flag = (zero_page) ? __GFP_ZERO : 0;
2127 	unsigned int nent;
2128 	int i = 0;
2129 
2130 	nent = DIV_ROUND_UP(length, PAGE_SIZE);
2131 	sg = kmalloc(sizeof(struct scatterlist) * nent, GFP_KERNEL);
2132 	if (!sg)
2133 		return -ENOMEM;
2134 
2135 	sg_init_table(sg, nent);
2136 
2137 	while (length) {
2138 		u32 page_len = min_t(u32, length, PAGE_SIZE);
2139 		page = alloc_page(GFP_KERNEL | zero_flag);
2140 		if (!page)
2141 			goto out;
2142 
2143 		sg_set_page(&sg[i], page, page_len, 0);
2144 		length -= page_len;
2145 		i++;
2146 	}
2147 	*sgl = sg;
2148 	*nents = nent;
2149 	return 0;
2150 
2151 out:
2152 	while (i > 0) {
2153 		i--;
2154 		__free_page(sg_page(&sg[i]));
2155 	}
2156 	kfree(sg);
2157 	return -ENOMEM;
2158 }
2159 
2160 /*
2161  * Allocate any required resources to execute the command.  For writes we
2162  * might not have the payload yet, so notify the fabric via a call to
2163  * ->write_pending instead. Otherwise place it on the execution queue.
2164  */
2165 sense_reason_t
2166 transport_generic_new_cmd(struct se_cmd *cmd)
2167 {
2168 	int ret = 0;
2169 
2170 	/*
2171 	 * Determine is the TCM fabric module has already allocated physical
2172 	 * memory, and is directly calling transport_generic_map_mem_to_cmd()
2173 	 * beforehand.
2174 	 */
2175 	if (!(cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) &&
2176 	    cmd->data_length) {
2177 		bool zero_flag = !(cmd->se_cmd_flags & SCF_SCSI_DATA_CDB);
2178 
2179 		if ((cmd->se_cmd_flags & SCF_BIDI) ||
2180 		    (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE)) {
2181 			u32 bidi_length;
2182 
2183 			if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE)
2184 				bidi_length = cmd->t_task_nolb *
2185 					      cmd->se_dev->dev_attrib.block_size;
2186 			else
2187 				bidi_length = cmd->data_length;
2188 
2189 			ret = target_alloc_sgl(&cmd->t_bidi_data_sg,
2190 					       &cmd->t_bidi_data_nents,
2191 					       bidi_length, zero_flag);
2192 			if (ret < 0)
2193 				return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2194 		}
2195 
2196 		ret = target_alloc_sgl(&cmd->t_data_sg, &cmd->t_data_nents,
2197 				       cmd->data_length, zero_flag);
2198 		if (ret < 0)
2199 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2200 	}
2201 	/*
2202 	 * If this command is not a write we can execute it right here,
2203 	 * for write buffers we need to notify the fabric driver first
2204 	 * and let it call back once the write buffers are ready.
2205 	 */
2206 	target_add_to_state_list(cmd);
2207 	if (cmd->data_direction != DMA_TO_DEVICE) {
2208 		target_execute_cmd(cmd);
2209 		return 0;
2210 	}
2211 	transport_cmd_check_stop(cmd, false, true);
2212 
2213 	ret = cmd->se_tfo->write_pending(cmd);
2214 	if (ret == -EAGAIN || ret == -ENOMEM)
2215 		goto queue_full;
2216 
2217 	/* fabric drivers should only return -EAGAIN or -ENOMEM as error */
2218 	WARN_ON(ret);
2219 
2220 	return (!ret) ? 0 : TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2221 
2222 queue_full:
2223 	pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n", cmd);
2224 	cmd->t_state = TRANSPORT_COMPLETE_QF_WP;
2225 	transport_handle_queue_full(cmd, cmd->se_dev);
2226 	return 0;
2227 }
2228 EXPORT_SYMBOL(transport_generic_new_cmd);
2229 
2230 static void transport_write_pending_qf(struct se_cmd *cmd)
2231 {
2232 	int ret;
2233 
2234 	ret = cmd->se_tfo->write_pending(cmd);
2235 	if (ret == -EAGAIN || ret == -ENOMEM) {
2236 		pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n",
2237 			 cmd);
2238 		transport_handle_queue_full(cmd, cmd->se_dev);
2239 	}
2240 }
2241 
2242 int transport_generic_free_cmd(struct se_cmd *cmd, int wait_for_tasks)
2243 {
2244 	unsigned long flags;
2245 	int ret = 0;
2246 
2247 	if (!(cmd->se_cmd_flags & SCF_SE_LUN_CMD)) {
2248 		if (wait_for_tasks && (cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
2249 			 transport_wait_for_tasks(cmd);
2250 
2251 		ret = transport_release_cmd(cmd);
2252 	} else {
2253 		if (wait_for_tasks)
2254 			transport_wait_for_tasks(cmd);
2255 		/*
2256 		 * Handle WRITE failure case where transport_generic_new_cmd()
2257 		 * has already added se_cmd to state_list, but fabric has
2258 		 * failed command before I/O submission.
2259 		 */
2260 		if (cmd->state_active) {
2261 			spin_lock_irqsave(&cmd->t_state_lock, flags);
2262 			target_remove_from_state_list(cmd);
2263 			spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2264 		}
2265 
2266 		if (cmd->se_lun)
2267 			transport_lun_remove_cmd(cmd);
2268 
2269 		ret = transport_put_cmd(cmd);
2270 	}
2271 	return ret;
2272 }
2273 EXPORT_SYMBOL(transport_generic_free_cmd);
2274 
2275 /* target_get_sess_cmd - Add command to active ->sess_cmd_list
2276  * @se_sess:	session to reference
2277  * @se_cmd:	command descriptor to add
2278  * @ack_kref:	Signal that fabric will perform an ack target_put_sess_cmd()
2279  */
2280 int target_get_sess_cmd(struct se_session *se_sess, struct se_cmd *se_cmd,
2281 			       bool ack_kref)
2282 {
2283 	unsigned long flags;
2284 	int ret = 0;
2285 
2286 	kref_init(&se_cmd->cmd_kref);
2287 	/*
2288 	 * Add a second kref if the fabric caller is expecting to handle
2289 	 * fabric acknowledgement that requires two target_put_sess_cmd()
2290 	 * invocations before se_cmd descriptor release.
2291 	 */
2292 	if (ack_kref == true) {
2293 		kref_get(&se_cmd->cmd_kref);
2294 		se_cmd->se_cmd_flags |= SCF_ACK_KREF;
2295 	}
2296 
2297 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2298 	if (se_sess->sess_tearing_down) {
2299 		ret = -ESHUTDOWN;
2300 		goto out;
2301 	}
2302 	list_add_tail(&se_cmd->se_cmd_list, &se_sess->sess_cmd_list);
2303 out:
2304 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2305 	return ret;
2306 }
2307 EXPORT_SYMBOL(target_get_sess_cmd);
2308 
2309 static void target_release_cmd_kref(struct kref *kref)
2310 {
2311 	struct se_cmd *se_cmd = container_of(kref, struct se_cmd, cmd_kref);
2312 	struct se_session *se_sess = se_cmd->se_sess;
2313 
2314 	if (list_empty(&se_cmd->se_cmd_list)) {
2315 		spin_unlock(&se_sess->sess_cmd_lock);
2316 		se_cmd->se_tfo->release_cmd(se_cmd);
2317 		return;
2318 	}
2319 	if (se_sess->sess_tearing_down && se_cmd->cmd_wait_set) {
2320 		spin_unlock(&se_sess->sess_cmd_lock);
2321 		complete(&se_cmd->cmd_wait_comp);
2322 		return;
2323 	}
2324 	list_del(&se_cmd->se_cmd_list);
2325 	spin_unlock(&se_sess->sess_cmd_lock);
2326 
2327 	se_cmd->se_tfo->release_cmd(se_cmd);
2328 }
2329 
2330 /* target_put_sess_cmd - Check for active I/O shutdown via kref_put
2331  * @se_sess:	session to reference
2332  * @se_cmd:	command descriptor to drop
2333  */
2334 int target_put_sess_cmd(struct se_session *se_sess, struct se_cmd *se_cmd)
2335 {
2336 	return kref_put_spinlock_irqsave(&se_cmd->cmd_kref, target_release_cmd_kref,
2337 			&se_sess->sess_cmd_lock);
2338 }
2339 EXPORT_SYMBOL(target_put_sess_cmd);
2340 
2341 /* target_sess_cmd_list_set_waiting - Flag all commands in
2342  *         sess_cmd_list to complete cmd_wait_comp.  Set
2343  *         sess_tearing_down so no more commands are queued.
2344  * @se_sess:	session to flag
2345  */
2346 void target_sess_cmd_list_set_waiting(struct se_session *se_sess)
2347 {
2348 	struct se_cmd *se_cmd;
2349 	unsigned long flags;
2350 
2351 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2352 	if (se_sess->sess_tearing_down) {
2353 		spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2354 		return;
2355 	}
2356 	se_sess->sess_tearing_down = 1;
2357 	list_splice_init(&se_sess->sess_cmd_list, &se_sess->sess_wait_list);
2358 
2359 	list_for_each_entry(se_cmd, &se_sess->sess_wait_list, se_cmd_list)
2360 		se_cmd->cmd_wait_set = 1;
2361 
2362 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2363 }
2364 EXPORT_SYMBOL(target_sess_cmd_list_set_waiting);
2365 
2366 /* target_wait_for_sess_cmds - Wait for outstanding descriptors
2367  * @se_sess:    session to wait for active I/O
2368  */
2369 void target_wait_for_sess_cmds(struct se_session *se_sess)
2370 {
2371 	struct se_cmd *se_cmd, *tmp_cmd;
2372 	unsigned long flags;
2373 
2374 	list_for_each_entry_safe(se_cmd, tmp_cmd,
2375 				&se_sess->sess_wait_list, se_cmd_list) {
2376 		list_del(&se_cmd->se_cmd_list);
2377 
2378 		pr_debug("Waiting for se_cmd: %p t_state: %d, fabric state:"
2379 			" %d\n", se_cmd, se_cmd->t_state,
2380 			se_cmd->se_tfo->get_cmd_state(se_cmd));
2381 
2382 		wait_for_completion(&se_cmd->cmd_wait_comp);
2383 		pr_debug("After cmd_wait_comp: se_cmd: %p t_state: %d"
2384 			" fabric state: %d\n", se_cmd, se_cmd->t_state,
2385 			se_cmd->se_tfo->get_cmd_state(se_cmd));
2386 
2387 		se_cmd->se_tfo->release_cmd(se_cmd);
2388 	}
2389 
2390 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2391 	WARN_ON(!list_empty(&se_sess->sess_cmd_list));
2392 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2393 
2394 }
2395 EXPORT_SYMBOL(target_wait_for_sess_cmds);
2396 
2397 /*	transport_lun_wait_for_tasks():
2398  *
2399  *	Called from ConfigFS context to stop the passed struct se_cmd to allow
2400  *	an struct se_lun to be successfully shutdown.
2401  */
2402 static int transport_lun_wait_for_tasks(struct se_cmd *cmd, struct se_lun *lun)
2403 {
2404 	unsigned long flags;
2405 	int ret = 0;
2406 
2407 	/*
2408 	 * If the frontend has already requested this struct se_cmd to
2409 	 * be stopped, we can safely ignore this struct se_cmd.
2410 	 */
2411 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2412 	if (cmd->transport_state & CMD_T_STOP) {
2413 		cmd->transport_state &= ~CMD_T_LUN_STOP;
2414 
2415 		pr_debug("ConfigFS ITT[0x%08x] - CMD_T_STOP, skipping\n",
2416 			 cmd->se_tfo->get_task_tag(cmd));
2417 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2418 		transport_cmd_check_stop(cmd, false, false);
2419 		return -EPERM;
2420 	}
2421 	cmd->transport_state |= CMD_T_LUN_FE_STOP;
2422 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2423 
2424 	// XXX: audit task_flags checks.
2425 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2426 	if ((cmd->transport_state & CMD_T_BUSY) &&
2427 	    (cmd->transport_state & CMD_T_SENT)) {
2428 		if (!target_stop_cmd(cmd, &flags))
2429 			ret++;
2430 	}
2431 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2432 
2433 	pr_debug("ConfigFS: cmd: %p stop tasks ret:"
2434 			" %d\n", cmd, ret);
2435 	if (!ret) {
2436 		pr_debug("ConfigFS: ITT[0x%08x] - stopping cmd....\n",
2437 				cmd->se_tfo->get_task_tag(cmd));
2438 		wait_for_completion(&cmd->transport_lun_stop_comp);
2439 		pr_debug("ConfigFS: ITT[0x%08x] - stopped cmd....\n",
2440 				cmd->se_tfo->get_task_tag(cmd));
2441 	}
2442 
2443 	return 0;
2444 }
2445 
2446 static void __transport_clear_lun_from_sessions(struct se_lun *lun)
2447 {
2448 	struct se_cmd *cmd = NULL;
2449 	unsigned long lun_flags, cmd_flags;
2450 	/*
2451 	 * Do exception processing and return CHECK_CONDITION status to the
2452 	 * Initiator Port.
2453 	 */
2454 	spin_lock_irqsave(&lun->lun_cmd_lock, lun_flags);
2455 	while (!list_empty(&lun->lun_cmd_list)) {
2456 		cmd = list_first_entry(&lun->lun_cmd_list,
2457 		       struct se_cmd, se_lun_node);
2458 		list_del_init(&cmd->se_lun_node);
2459 
2460 		spin_lock(&cmd->t_state_lock);
2461 		pr_debug("SE_LUN[%d] - Setting cmd->transport"
2462 			"_lun_stop for  ITT: 0x%08x\n",
2463 			cmd->se_lun->unpacked_lun,
2464 			cmd->se_tfo->get_task_tag(cmd));
2465 		cmd->transport_state |= CMD_T_LUN_STOP;
2466 		spin_unlock(&cmd->t_state_lock);
2467 
2468 		spin_unlock_irqrestore(&lun->lun_cmd_lock, lun_flags);
2469 
2470 		if (!cmd->se_lun) {
2471 			pr_err("ITT: 0x%08x, [i,t]_state: %u/%u\n",
2472 				cmd->se_tfo->get_task_tag(cmd),
2473 				cmd->se_tfo->get_cmd_state(cmd), cmd->t_state);
2474 			BUG();
2475 		}
2476 		/*
2477 		 * If the Storage engine still owns the iscsi_cmd_t, determine
2478 		 * and/or stop its context.
2479 		 */
2480 		pr_debug("SE_LUN[%d] - ITT: 0x%08x before transport"
2481 			"_lun_wait_for_tasks()\n", cmd->se_lun->unpacked_lun,
2482 			cmd->se_tfo->get_task_tag(cmd));
2483 
2484 		if (transport_lun_wait_for_tasks(cmd, cmd->se_lun) < 0) {
2485 			spin_lock_irqsave(&lun->lun_cmd_lock, lun_flags);
2486 			continue;
2487 		}
2488 
2489 		pr_debug("SE_LUN[%d] - ITT: 0x%08x after transport_lun"
2490 			"_wait_for_tasks(): SUCCESS\n",
2491 			cmd->se_lun->unpacked_lun,
2492 			cmd->se_tfo->get_task_tag(cmd));
2493 
2494 		spin_lock_irqsave(&cmd->t_state_lock, cmd_flags);
2495 		if (!(cmd->transport_state & CMD_T_DEV_ACTIVE)) {
2496 			spin_unlock_irqrestore(&cmd->t_state_lock, cmd_flags);
2497 			goto check_cond;
2498 		}
2499 		cmd->transport_state &= ~CMD_T_DEV_ACTIVE;
2500 		target_remove_from_state_list(cmd);
2501 		spin_unlock_irqrestore(&cmd->t_state_lock, cmd_flags);
2502 
2503 		/*
2504 		 * The Storage engine stopped this struct se_cmd before it was
2505 		 * send to the fabric frontend for delivery back to the
2506 		 * Initiator Node.  Return this SCSI CDB back with an
2507 		 * CHECK_CONDITION status.
2508 		 */
2509 check_cond:
2510 		transport_send_check_condition_and_sense(cmd,
2511 				TCM_NON_EXISTENT_LUN, 0);
2512 		/*
2513 		 *  If the fabric frontend is waiting for this iscsi_cmd_t to
2514 		 * be released, notify the waiting thread now that LU has
2515 		 * finished accessing it.
2516 		 */
2517 		spin_lock_irqsave(&cmd->t_state_lock, cmd_flags);
2518 		if (cmd->transport_state & CMD_T_LUN_FE_STOP) {
2519 			pr_debug("SE_LUN[%d] - Detected FE stop for"
2520 				" struct se_cmd: %p ITT: 0x%08x\n",
2521 				lun->unpacked_lun,
2522 				cmd, cmd->se_tfo->get_task_tag(cmd));
2523 
2524 			spin_unlock_irqrestore(&cmd->t_state_lock,
2525 					cmd_flags);
2526 			transport_cmd_check_stop(cmd, false, false);
2527 			complete(&cmd->transport_lun_fe_stop_comp);
2528 			spin_lock_irqsave(&lun->lun_cmd_lock, lun_flags);
2529 			continue;
2530 		}
2531 		pr_debug("SE_LUN[%d] - ITT: 0x%08x finished processing\n",
2532 			lun->unpacked_lun, cmd->se_tfo->get_task_tag(cmd));
2533 
2534 		spin_unlock_irqrestore(&cmd->t_state_lock, cmd_flags);
2535 		spin_lock_irqsave(&lun->lun_cmd_lock, lun_flags);
2536 	}
2537 	spin_unlock_irqrestore(&lun->lun_cmd_lock, lun_flags);
2538 }
2539 
2540 static int transport_clear_lun_thread(void *p)
2541 {
2542 	struct se_lun *lun = p;
2543 
2544 	__transport_clear_lun_from_sessions(lun);
2545 	complete(&lun->lun_shutdown_comp);
2546 
2547 	return 0;
2548 }
2549 
2550 int transport_clear_lun_from_sessions(struct se_lun *lun)
2551 {
2552 	struct task_struct *kt;
2553 
2554 	kt = kthread_run(transport_clear_lun_thread, lun,
2555 			"tcm_cl_%u", lun->unpacked_lun);
2556 	if (IS_ERR(kt)) {
2557 		pr_err("Unable to start clear_lun thread\n");
2558 		return PTR_ERR(kt);
2559 	}
2560 	wait_for_completion(&lun->lun_shutdown_comp);
2561 
2562 	return 0;
2563 }
2564 
2565 /**
2566  * transport_wait_for_tasks - wait for completion to occur
2567  * @cmd:	command to wait
2568  *
2569  * Called from frontend fabric context to wait for storage engine
2570  * to pause and/or release frontend generated struct se_cmd.
2571  */
2572 bool transport_wait_for_tasks(struct se_cmd *cmd)
2573 {
2574 	unsigned long flags;
2575 
2576 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2577 	if (!(cmd->se_cmd_flags & SCF_SE_LUN_CMD) &&
2578 	    !(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)) {
2579 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2580 		return false;
2581 	}
2582 
2583 	if (!(cmd->se_cmd_flags & SCF_SUPPORTED_SAM_OPCODE) &&
2584 	    !(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)) {
2585 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2586 		return false;
2587 	}
2588 	/*
2589 	 * If we are already stopped due to an external event (ie: LUN shutdown)
2590 	 * sleep until the connection can have the passed struct se_cmd back.
2591 	 * The cmd->transport_lun_stopped_sem will be upped by
2592 	 * transport_clear_lun_from_sessions() once the ConfigFS context caller
2593 	 * has completed its operation on the struct se_cmd.
2594 	 */
2595 	if (cmd->transport_state & CMD_T_LUN_STOP) {
2596 		pr_debug("wait_for_tasks: Stopping"
2597 			" wait_for_completion(&cmd->t_tasktransport_lun_fe"
2598 			"_stop_comp); for ITT: 0x%08x\n",
2599 			cmd->se_tfo->get_task_tag(cmd));
2600 		/*
2601 		 * There is a special case for WRITES where a FE exception +
2602 		 * LUN shutdown means ConfigFS context is still sleeping on
2603 		 * transport_lun_stop_comp in transport_lun_wait_for_tasks().
2604 		 * We go ahead and up transport_lun_stop_comp just to be sure
2605 		 * here.
2606 		 */
2607 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2608 		complete(&cmd->transport_lun_stop_comp);
2609 		wait_for_completion(&cmd->transport_lun_fe_stop_comp);
2610 		spin_lock_irqsave(&cmd->t_state_lock, flags);
2611 
2612 		target_remove_from_state_list(cmd);
2613 		/*
2614 		 * At this point, the frontend who was the originator of this
2615 		 * struct se_cmd, now owns the structure and can be released through
2616 		 * normal means below.
2617 		 */
2618 		pr_debug("wait_for_tasks: Stopped"
2619 			" wait_for_completion(&cmd->t_tasktransport_lun_fe_"
2620 			"stop_comp); for ITT: 0x%08x\n",
2621 			cmd->se_tfo->get_task_tag(cmd));
2622 
2623 		cmd->transport_state &= ~CMD_T_LUN_STOP;
2624 	}
2625 
2626 	if (!(cmd->transport_state & CMD_T_ACTIVE)) {
2627 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2628 		return false;
2629 	}
2630 
2631 	cmd->transport_state |= CMD_T_STOP;
2632 
2633 	pr_debug("wait_for_tasks: Stopping %p ITT: 0x%08x"
2634 		" i_state: %d, t_state: %d, CMD_T_STOP\n",
2635 		cmd, cmd->se_tfo->get_task_tag(cmd),
2636 		cmd->se_tfo->get_cmd_state(cmd), cmd->t_state);
2637 
2638 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2639 
2640 	wait_for_completion(&cmd->t_transport_stop_comp);
2641 
2642 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2643 	cmd->transport_state &= ~(CMD_T_ACTIVE | CMD_T_STOP);
2644 
2645 	pr_debug("wait_for_tasks: Stopped wait_for_completion("
2646 		"&cmd->t_transport_stop_comp) for ITT: 0x%08x\n",
2647 		cmd->se_tfo->get_task_tag(cmd));
2648 
2649 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2650 
2651 	return true;
2652 }
2653 EXPORT_SYMBOL(transport_wait_for_tasks);
2654 
2655 static int transport_get_sense_codes(
2656 	struct se_cmd *cmd,
2657 	u8 *asc,
2658 	u8 *ascq)
2659 {
2660 	*asc = cmd->scsi_asc;
2661 	*ascq = cmd->scsi_ascq;
2662 
2663 	return 0;
2664 }
2665 
2666 int
2667 transport_send_check_condition_and_sense(struct se_cmd *cmd,
2668 		sense_reason_t reason, int from_transport)
2669 {
2670 	unsigned char *buffer = cmd->sense_buffer;
2671 	unsigned long flags;
2672 	u8 asc = 0, ascq = 0;
2673 
2674 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2675 	if (cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION) {
2676 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2677 		return 0;
2678 	}
2679 	cmd->se_cmd_flags |= SCF_SENT_CHECK_CONDITION;
2680 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2681 
2682 	if (!reason && from_transport)
2683 		goto after_reason;
2684 
2685 	if (!from_transport)
2686 		cmd->se_cmd_flags |= SCF_EMULATED_TASK_SENSE;
2687 
2688 	/*
2689 	 * Actual SENSE DATA, see SPC-3 7.23.2  SPC_SENSE_KEY_OFFSET uses
2690 	 * SENSE KEY values from include/scsi/scsi.h
2691 	 */
2692 	switch (reason) {
2693 	case TCM_NO_SENSE:
2694 		/* CURRENT ERROR */
2695 		buffer[0] = 0x70;
2696 		buffer[SPC_ADD_SENSE_LEN_OFFSET] = 10;
2697 		/* Not Ready */
2698 		buffer[SPC_SENSE_KEY_OFFSET] = NOT_READY;
2699 		/* NO ADDITIONAL SENSE INFORMATION */
2700 		buffer[SPC_ASC_KEY_OFFSET] = 0;
2701 		buffer[SPC_ASCQ_KEY_OFFSET] = 0;
2702 		break;
2703 	case TCM_NON_EXISTENT_LUN:
2704 		/* CURRENT ERROR */
2705 		buffer[0] = 0x70;
2706 		buffer[SPC_ADD_SENSE_LEN_OFFSET] = 10;
2707 		/* ILLEGAL REQUEST */
2708 		buffer[SPC_SENSE_KEY_OFFSET] = ILLEGAL_REQUEST;
2709 		/* LOGICAL UNIT NOT SUPPORTED */
2710 		buffer[SPC_ASC_KEY_OFFSET] = 0x25;
2711 		break;
2712 	case TCM_UNSUPPORTED_SCSI_OPCODE:
2713 	case TCM_SECTOR_COUNT_TOO_MANY:
2714 		/* CURRENT ERROR */
2715 		buffer[0] = 0x70;
2716 		buffer[SPC_ADD_SENSE_LEN_OFFSET] = 10;
2717 		/* ILLEGAL REQUEST */
2718 		buffer[SPC_SENSE_KEY_OFFSET] = ILLEGAL_REQUEST;
2719 		/* INVALID COMMAND OPERATION CODE */
2720 		buffer[SPC_ASC_KEY_OFFSET] = 0x20;
2721 		break;
2722 	case TCM_UNKNOWN_MODE_PAGE:
2723 		/* CURRENT ERROR */
2724 		buffer[0] = 0x70;
2725 		buffer[SPC_ADD_SENSE_LEN_OFFSET] = 10;
2726 		/* ILLEGAL REQUEST */
2727 		buffer[SPC_SENSE_KEY_OFFSET] = ILLEGAL_REQUEST;
2728 		/* INVALID FIELD IN CDB */
2729 		buffer[SPC_ASC_KEY_OFFSET] = 0x24;
2730 		break;
2731 	case TCM_CHECK_CONDITION_ABORT_CMD:
2732 		/* CURRENT ERROR */
2733 		buffer[0] = 0x70;
2734 		buffer[SPC_ADD_SENSE_LEN_OFFSET] = 10;
2735 		/* ABORTED COMMAND */
2736 		buffer[SPC_SENSE_KEY_OFFSET] = ABORTED_COMMAND;
2737 		/* BUS DEVICE RESET FUNCTION OCCURRED */
2738 		buffer[SPC_ASC_KEY_OFFSET] = 0x29;
2739 		buffer[SPC_ASCQ_KEY_OFFSET] = 0x03;
2740 		break;
2741 	case TCM_INCORRECT_AMOUNT_OF_DATA:
2742 		/* CURRENT ERROR */
2743 		buffer[0] = 0x70;
2744 		buffer[SPC_ADD_SENSE_LEN_OFFSET] = 10;
2745 		/* ABORTED COMMAND */
2746 		buffer[SPC_SENSE_KEY_OFFSET] = ABORTED_COMMAND;
2747 		/* WRITE ERROR */
2748 		buffer[SPC_ASC_KEY_OFFSET] = 0x0c;
2749 		/* NOT ENOUGH UNSOLICITED DATA */
2750 		buffer[SPC_ASCQ_KEY_OFFSET] = 0x0d;
2751 		break;
2752 	case TCM_INVALID_CDB_FIELD:
2753 		/* CURRENT ERROR */
2754 		buffer[0] = 0x70;
2755 		buffer[SPC_ADD_SENSE_LEN_OFFSET] = 10;
2756 		/* ILLEGAL REQUEST */
2757 		buffer[SPC_SENSE_KEY_OFFSET] = ILLEGAL_REQUEST;
2758 		/* INVALID FIELD IN CDB */
2759 		buffer[SPC_ASC_KEY_OFFSET] = 0x24;
2760 		break;
2761 	case TCM_INVALID_PARAMETER_LIST:
2762 		/* CURRENT ERROR */
2763 		buffer[0] = 0x70;
2764 		buffer[SPC_ADD_SENSE_LEN_OFFSET] = 10;
2765 		/* ILLEGAL REQUEST */
2766 		buffer[SPC_SENSE_KEY_OFFSET] = ILLEGAL_REQUEST;
2767 		/* INVALID FIELD IN PARAMETER LIST */
2768 		buffer[SPC_ASC_KEY_OFFSET] = 0x26;
2769 		break;
2770 	case TCM_PARAMETER_LIST_LENGTH_ERROR:
2771 		/* CURRENT ERROR */
2772 		buffer[0] = 0x70;
2773 		buffer[SPC_ADD_SENSE_LEN_OFFSET] = 10;
2774 		/* ILLEGAL REQUEST */
2775 		buffer[SPC_SENSE_KEY_OFFSET] = ILLEGAL_REQUEST;
2776 		/* PARAMETER LIST LENGTH ERROR */
2777 		buffer[SPC_ASC_KEY_OFFSET] = 0x1a;
2778 		break;
2779 	case TCM_UNEXPECTED_UNSOLICITED_DATA:
2780 		/* CURRENT ERROR */
2781 		buffer[0] = 0x70;
2782 		buffer[SPC_ADD_SENSE_LEN_OFFSET] = 10;
2783 		/* ABORTED COMMAND */
2784 		buffer[SPC_SENSE_KEY_OFFSET] = ABORTED_COMMAND;
2785 		/* WRITE ERROR */
2786 		buffer[SPC_ASC_KEY_OFFSET] = 0x0c;
2787 		/* UNEXPECTED_UNSOLICITED_DATA */
2788 		buffer[SPC_ASCQ_KEY_OFFSET] = 0x0c;
2789 		break;
2790 	case TCM_SERVICE_CRC_ERROR:
2791 		/* CURRENT ERROR */
2792 		buffer[0] = 0x70;
2793 		buffer[SPC_ADD_SENSE_LEN_OFFSET] = 10;
2794 		/* ABORTED COMMAND */
2795 		buffer[SPC_SENSE_KEY_OFFSET] = ABORTED_COMMAND;
2796 		/* PROTOCOL SERVICE CRC ERROR */
2797 		buffer[SPC_ASC_KEY_OFFSET] = 0x47;
2798 		/* N/A */
2799 		buffer[SPC_ASCQ_KEY_OFFSET] = 0x05;
2800 		break;
2801 	case TCM_SNACK_REJECTED:
2802 		/* CURRENT ERROR */
2803 		buffer[0] = 0x70;
2804 		buffer[SPC_ADD_SENSE_LEN_OFFSET] = 10;
2805 		/* ABORTED COMMAND */
2806 		buffer[SPC_SENSE_KEY_OFFSET] = ABORTED_COMMAND;
2807 		/* READ ERROR */
2808 		buffer[SPC_ASC_KEY_OFFSET] = 0x11;
2809 		/* FAILED RETRANSMISSION REQUEST */
2810 		buffer[SPC_ASCQ_KEY_OFFSET] = 0x13;
2811 		break;
2812 	case TCM_WRITE_PROTECTED:
2813 		/* CURRENT ERROR */
2814 		buffer[0] = 0x70;
2815 		buffer[SPC_ADD_SENSE_LEN_OFFSET] = 10;
2816 		/* DATA PROTECT */
2817 		buffer[SPC_SENSE_KEY_OFFSET] = DATA_PROTECT;
2818 		/* WRITE PROTECTED */
2819 		buffer[SPC_ASC_KEY_OFFSET] = 0x27;
2820 		break;
2821 	case TCM_ADDRESS_OUT_OF_RANGE:
2822 		/* CURRENT ERROR */
2823 		buffer[0] = 0x70;
2824 		buffer[SPC_ADD_SENSE_LEN_OFFSET] = 10;
2825 		/* ILLEGAL REQUEST */
2826 		buffer[SPC_SENSE_KEY_OFFSET] = ILLEGAL_REQUEST;
2827 		/* LOGICAL BLOCK ADDRESS OUT OF RANGE */
2828 		buffer[SPC_ASC_KEY_OFFSET] = 0x21;
2829 		break;
2830 	case TCM_CHECK_CONDITION_UNIT_ATTENTION:
2831 		/* CURRENT ERROR */
2832 		buffer[0] = 0x70;
2833 		buffer[SPC_ADD_SENSE_LEN_OFFSET] = 10;
2834 		/* UNIT ATTENTION */
2835 		buffer[SPC_SENSE_KEY_OFFSET] = UNIT_ATTENTION;
2836 		core_scsi3_ua_for_check_condition(cmd, &asc, &ascq);
2837 		buffer[SPC_ASC_KEY_OFFSET] = asc;
2838 		buffer[SPC_ASCQ_KEY_OFFSET] = ascq;
2839 		break;
2840 	case TCM_CHECK_CONDITION_NOT_READY:
2841 		/* CURRENT ERROR */
2842 		buffer[0] = 0x70;
2843 		buffer[SPC_ADD_SENSE_LEN_OFFSET] = 10;
2844 		/* Not Ready */
2845 		buffer[SPC_SENSE_KEY_OFFSET] = NOT_READY;
2846 		transport_get_sense_codes(cmd, &asc, &ascq);
2847 		buffer[SPC_ASC_KEY_OFFSET] = asc;
2848 		buffer[SPC_ASCQ_KEY_OFFSET] = ascq;
2849 		break;
2850 	case TCM_MISCOMPARE_VERIFY:
2851 		/* CURRENT ERROR */
2852 		buffer[0] = 0x70;
2853 		buffer[SPC_ADD_SENSE_LEN_OFFSET] = 10;
2854 		buffer[SPC_SENSE_KEY_OFFSET] = MISCOMPARE;
2855 		/* MISCOMPARE DURING VERIFY OPERATION */
2856 		buffer[SPC_ASC_KEY_OFFSET] = 0x1d;
2857 		buffer[SPC_ASCQ_KEY_OFFSET] = 0x00;
2858 		break;
2859 	case TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE:
2860 	default:
2861 		/* CURRENT ERROR */
2862 		buffer[0] = 0x70;
2863 		buffer[SPC_ADD_SENSE_LEN_OFFSET] = 10;
2864 		/*
2865 		 * Returning ILLEGAL REQUEST would cause immediate IO errors on
2866 		 * Solaris initiators.  Returning NOT READY instead means the
2867 		 * operations will be retried a finite number of times and we
2868 		 * can survive intermittent errors.
2869 		 */
2870 		buffer[SPC_SENSE_KEY_OFFSET] = NOT_READY;
2871 		/* LOGICAL UNIT COMMUNICATION FAILURE */
2872 		buffer[SPC_ASC_KEY_OFFSET] = 0x08;
2873 		break;
2874 	}
2875 	/*
2876 	 * This code uses linux/include/scsi/scsi.h SAM status codes!
2877 	 */
2878 	cmd->scsi_status = SAM_STAT_CHECK_CONDITION;
2879 	/*
2880 	 * Automatically padded, this value is encoded in the fabric's
2881 	 * data_length response PDU containing the SCSI defined sense data.
2882 	 */
2883 	cmd->scsi_sense_length  = TRANSPORT_SENSE_BUFFER;
2884 
2885 after_reason:
2886 	trace_target_cmd_complete(cmd);
2887 	return cmd->se_tfo->queue_status(cmd);
2888 }
2889 EXPORT_SYMBOL(transport_send_check_condition_and_sense);
2890 
2891 int transport_check_aborted_status(struct se_cmd *cmd, int send_status)
2892 {
2893 	if (!(cmd->transport_state & CMD_T_ABORTED))
2894 		return 0;
2895 
2896 	if (!send_status || (cmd->se_cmd_flags & SCF_SENT_DELAYED_TAS))
2897 		return 1;
2898 
2899 	pr_debug("Sending delayed SAM_STAT_TASK_ABORTED status for CDB: 0x%02x ITT: 0x%08x\n",
2900 		 cmd->t_task_cdb[0], cmd->se_tfo->get_task_tag(cmd));
2901 
2902 	cmd->se_cmd_flags |= SCF_SENT_DELAYED_TAS;
2903 	trace_target_cmd_complete(cmd);
2904 	cmd->se_tfo->queue_status(cmd);
2905 
2906 	return 1;
2907 }
2908 EXPORT_SYMBOL(transport_check_aborted_status);
2909 
2910 void transport_send_task_abort(struct se_cmd *cmd)
2911 {
2912 	unsigned long flags;
2913 
2914 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2915 	if (cmd->se_cmd_flags & (SCF_SENT_CHECK_CONDITION | SCF_SENT_DELAYED_TAS)) {
2916 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2917 		return;
2918 	}
2919 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2920 
2921 	/*
2922 	 * If there are still expected incoming fabric WRITEs, we wait
2923 	 * until until they have completed before sending a TASK_ABORTED
2924 	 * response.  This response with TASK_ABORTED status will be
2925 	 * queued back to fabric module by transport_check_aborted_status().
2926 	 */
2927 	if (cmd->data_direction == DMA_TO_DEVICE) {
2928 		if (cmd->se_tfo->write_pending_status(cmd) != 0) {
2929 			cmd->transport_state |= CMD_T_ABORTED;
2930 			smp_mb__after_atomic_inc();
2931 		}
2932 	}
2933 	cmd->scsi_status = SAM_STAT_TASK_ABORTED;
2934 
2935 	transport_lun_remove_cmd(cmd);
2936 
2937 	pr_debug("Setting SAM_STAT_TASK_ABORTED status for CDB: 0x%02x,"
2938 		" ITT: 0x%08x\n", cmd->t_task_cdb[0],
2939 		cmd->se_tfo->get_task_tag(cmd));
2940 
2941 	trace_target_cmd_complete(cmd);
2942 	cmd->se_tfo->queue_status(cmd);
2943 }
2944 
2945 static void target_tmr_work(struct work_struct *work)
2946 {
2947 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
2948 	struct se_device *dev = cmd->se_dev;
2949 	struct se_tmr_req *tmr = cmd->se_tmr_req;
2950 	int ret;
2951 
2952 	switch (tmr->function) {
2953 	case TMR_ABORT_TASK:
2954 		core_tmr_abort_task(dev, tmr, cmd->se_sess);
2955 		break;
2956 	case TMR_ABORT_TASK_SET:
2957 	case TMR_CLEAR_ACA:
2958 	case TMR_CLEAR_TASK_SET:
2959 		tmr->response = TMR_TASK_MGMT_FUNCTION_NOT_SUPPORTED;
2960 		break;
2961 	case TMR_LUN_RESET:
2962 		ret = core_tmr_lun_reset(dev, tmr, NULL, NULL);
2963 		tmr->response = (!ret) ? TMR_FUNCTION_COMPLETE :
2964 					 TMR_FUNCTION_REJECTED;
2965 		break;
2966 	case TMR_TARGET_WARM_RESET:
2967 		tmr->response = TMR_FUNCTION_REJECTED;
2968 		break;
2969 	case TMR_TARGET_COLD_RESET:
2970 		tmr->response = TMR_FUNCTION_REJECTED;
2971 		break;
2972 	default:
2973 		pr_err("Uknown TMR function: 0x%02x.\n",
2974 				tmr->function);
2975 		tmr->response = TMR_FUNCTION_REJECTED;
2976 		break;
2977 	}
2978 
2979 	cmd->t_state = TRANSPORT_ISTATE_PROCESSING;
2980 	cmd->se_tfo->queue_tm_rsp(cmd);
2981 
2982 	transport_cmd_check_stop_to_fabric(cmd);
2983 }
2984 
2985 int transport_generic_handle_tmr(
2986 	struct se_cmd *cmd)
2987 {
2988 	INIT_WORK(&cmd->work, target_tmr_work);
2989 	queue_work(cmd->se_dev->tmr_wq, &cmd->work);
2990 	return 0;
2991 }
2992 EXPORT_SYMBOL(transport_generic_handle_tmr);
2993