xref: /linux/drivers/target/target_core_transport.c (revision 7cefa5a05dbda1f0bbbd98e9d2861b09a35cc6ea)
1 /*******************************************************************************
2  * Filename:  target_core_transport.c
3  *
4  * This file contains the Generic Target Engine Core.
5  *
6  * (c) Copyright 2002-2013 Datera, Inc.
7  *
8  * Nicholas A. Bellinger <nab@kernel.org>
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License as published by
12  * the Free Software Foundation; either version 2 of the License, or
13  * (at your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18  * GNU General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with this program; if not, write to the Free Software
22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
23  *
24  ******************************************************************************/
25 
26 #include <linux/net.h>
27 #include <linux/delay.h>
28 #include <linux/string.h>
29 #include <linux/timer.h>
30 #include <linux/slab.h>
31 #include <linux/spinlock.h>
32 #include <linux/kthread.h>
33 #include <linux/in.h>
34 #include <linux/cdrom.h>
35 #include <linux/module.h>
36 #include <linux/ratelimit.h>
37 #include <linux/vmalloc.h>
38 #include <asm/unaligned.h>
39 #include <net/sock.h>
40 #include <net/tcp.h>
41 #include <scsi/scsi_proto.h>
42 #include <scsi/scsi_common.h>
43 
44 #include <target/target_core_base.h>
45 #include <target/target_core_backend.h>
46 #include <target/target_core_fabric.h>
47 
48 #include "target_core_internal.h"
49 #include "target_core_alua.h"
50 #include "target_core_pr.h"
51 #include "target_core_ua.h"
52 
53 #define CREATE_TRACE_POINTS
54 #include <trace/events/target.h>
55 
56 static struct workqueue_struct *target_completion_wq;
57 static struct kmem_cache *se_sess_cache;
58 struct kmem_cache *se_ua_cache;
59 struct kmem_cache *t10_pr_reg_cache;
60 struct kmem_cache *t10_alua_lu_gp_cache;
61 struct kmem_cache *t10_alua_lu_gp_mem_cache;
62 struct kmem_cache *t10_alua_tg_pt_gp_cache;
63 struct kmem_cache *t10_alua_lba_map_cache;
64 struct kmem_cache *t10_alua_lba_map_mem_cache;
65 
66 static void transport_complete_task_attr(struct se_cmd *cmd);
67 static void transport_handle_queue_full(struct se_cmd *cmd,
68 		struct se_device *dev);
69 static int transport_put_cmd(struct se_cmd *cmd);
70 static void target_complete_ok_work(struct work_struct *work);
71 
72 int init_se_kmem_caches(void)
73 {
74 	se_sess_cache = kmem_cache_create("se_sess_cache",
75 			sizeof(struct se_session), __alignof__(struct se_session),
76 			0, NULL);
77 	if (!se_sess_cache) {
78 		pr_err("kmem_cache_create() for struct se_session"
79 				" failed\n");
80 		goto out;
81 	}
82 	se_ua_cache = kmem_cache_create("se_ua_cache",
83 			sizeof(struct se_ua), __alignof__(struct se_ua),
84 			0, NULL);
85 	if (!se_ua_cache) {
86 		pr_err("kmem_cache_create() for struct se_ua failed\n");
87 		goto out_free_sess_cache;
88 	}
89 	t10_pr_reg_cache = kmem_cache_create("t10_pr_reg_cache",
90 			sizeof(struct t10_pr_registration),
91 			__alignof__(struct t10_pr_registration), 0, NULL);
92 	if (!t10_pr_reg_cache) {
93 		pr_err("kmem_cache_create() for struct t10_pr_registration"
94 				" failed\n");
95 		goto out_free_ua_cache;
96 	}
97 	t10_alua_lu_gp_cache = kmem_cache_create("t10_alua_lu_gp_cache",
98 			sizeof(struct t10_alua_lu_gp), __alignof__(struct t10_alua_lu_gp),
99 			0, NULL);
100 	if (!t10_alua_lu_gp_cache) {
101 		pr_err("kmem_cache_create() for t10_alua_lu_gp_cache"
102 				" failed\n");
103 		goto out_free_pr_reg_cache;
104 	}
105 	t10_alua_lu_gp_mem_cache = kmem_cache_create("t10_alua_lu_gp_mem_cache",
106 			sizeof(struct t10_alua_lu_gp_member),
107 			__alignof__(struct t10_alua_lu_gp_member), 0, NULL);
108 	if (!t10_alua_lu_gp_mem_cache) {
109 		pr_err("kmem_cache_create() for t10_alua_lu_gp_mem_"
110 				"cache failed\n");
111 		goto out_free_lu_gp_cache;
112 	}
113 	t10_alua_tg_pt_gp_cache = kmem_cache_create("t10_alua_tg_pt_gp_cache",
114 			sizeof(struct t10_alua_tg_pt_gp),
115 			__alignof__(struct t10_alua_tg_pt_gp), 0, NULL);
116 	if (!t10_alua_tg_pt_gp_cache) {
117 		pr_err("kmem_cache_create() for t10_alua_tg_pt_gp_"
118 				"cache failed\n");
119 		goto out_free_lu_gp_mem_cache;
120 	}
121 	t10_alua_lba_map_cache = kmem_cache_create(
122 			"t10_alua_lba_map_cache",
123 			sizeof(struct t10_alua_lba_map),
124 			__alignof__(struct t10_alua_lba_map), 0, NULL);
125 	if (!t10_alua_lba_map_cache) {
126 		pr_err("kmem_cache_create() for t10_alua_lba_map_"
127 				"cache failed\n");
128 		goto out_free_tg_pt_gp_cache;
129 	}
130 	t10_alua_lba_map_mem_cache = kmem_cache_create(
131 			"t10_alua_lba_map_mem_cache",
132 			sizeof(struct t10_alua_lba_map_member),
133 			__alignof__(struct t10_alua_lba_map_member), 0, NULL);
134 	if (!t10_alua_lba_map_mem_cache) {
135 		pr_err("kmem_cache_create() for t10_alua_lba_map_mem_"
136 				"cache failed\n");
137 		goto out_free_lba_map_cache;
138 	}
139 
140 	target_completion_wq = alloc_workqueue("target_completion",
141 					       WQ_MEM_RECLAIM, 0);
142 	if (!target_completion_wq)
143 		goto out_free_lba_map_mem_cache;
144 
145 	return 0;
146 
147 out_free_lba_map_mem_cache:
148 	kmem_cache_destroy(t10_alua_lba_map_mem_cache);
149 out_free_lba_map_cache:
150 	kmem_cache_destroy(t10_alua_lba_map_cache);
151 out_free_tg_pt_gp_cache:
152 	kmem_cache_destroy(t10_alua_tg_pt_gp_cache);
153 out_free_lu_gp_mem_cache:
154 	kmem_cache_destroy(t10_alua_lu_gp_mem_cache);
155 out_free_lu_gp_cache:
156 	kmem_cache_destroy(t10_alua_lu_gp_cache);
157 out_free_pr_reg_cache:
158 	kmem_cache_destroy(t10_pr_reg_cache);
159 out_free_ua_cache:
160 	kmem_cache_destroy(se_ua_cache);
161 out_free_sess_cache:
162 	kmem_cache_destroy(se_sess_cache);
163 out:
164 	return -ENOMEM;
165 }
166 
167 void release_se_kmem_caches(void)
168 {
169 	destroy_workqueue(target_completion_wq);
170 	kmem_cache_destroy(se_sess_cache);
171 	kmem_cache_destroy(se_ua_cache);
172 	kmem_cache_destroy(t10_pr_reg_cache);
173 	kmem_cache_destroy(t10_alua_lu_gp_cache);
174 	kmem_cache_destroy(t10_alua_lu_gp_mem_cache);
175 	kmem_cache_destroy(t10_alua_tg_pt_gp_cache);
176 	kmem_cache_destroy(t10_alua_lba_map_cache);
177 	kmem_cache_destroy(t10_alua_lba_map_mem_cache);
178 }
179 
180 /* This code ensures unique mib indexes are handed out. */
181 static DEFINE_SPINLOCK(scsi_mib_index_lock);
182 static u32 scsi_mib_index[SCSI_INDEX_TYPE_MAX];
183 
184 /*
185  * Allocate a new row index for the entry type specified
186  */
187 u32 scsi_get_new_index(scsi_index_t type)
188 {
189 	u32 new_index;
190 
191 	BUG_ON((type < 0) || (type >= SCSI_INDEX_TYPE_MAX));
192 
193 	spin_lock(&scsi_mib_index_lock);
194 	new_index = ++scsi_mib_index[type];
195 	spin_unlock(&scsi_mib_index_lock);
196 
197 	return new_index;
198 }
199 
200 void transport_subsystem_check_init(void)
201 {
202 	int ret;
203 	static int sub_api_initialized;
204 
205 	if (sub_api_initialized)
206 		return;
207 
208 	ret = request_module("target_core_iblock");
209 	if (ret != 0)
210 		pr_err("Unable to load target_core_iblock\n");
211 
212 	ret = request_module("target_core_file");
213 	if (ret != 0)
214 		pr_err("Unable to load target_core_file\n");
215 
216 	ret = request_module("target_core_pscsi");
217 	if (ret != 0)
218 		pr_err("Unable to load target_core_pscsi\n");
219 
220 	ret = request_module("target_core_user");
221 	if (ret != 0)
222 		pr_err("Unable to load target_core_user\n");
223 
224 	sub_api_initialized = 1;
225 }
226 
227 struct se_session *transport_init_session(enum target_prot_op sup_prot_ops)
228 {
229 	struct se_session *se_sess;
230 
231 	se_sess = kmem_cache_zalloc(se_sess_cache, GFP_KERNEL);
232 	if (!se_sess) {
233 		pr_err("Unable to allocate struct se_session from"
234 				" se_sess_cache\n");
235 		return ERR_PTR(-ENOMEM);
236 	}
237 	INIT_LIST_HEAD(&se_sess->sess_list);
238 	INIT_LIST_HEAD(&se_sess->sess_acl_list);
239 	INIT_LIST_HEAD(&se_sess->sess_cmd_list);
240 	INIT_LIST_HEAD(&se_sess->sess_wait_list);
241 	spin_lock_init(&se_sess->sess_cmd_lock);
242 	se_sess->sup_prot_ops = sup_prot_ops;
243 
244 	return se_sess;
245 }
246 EXPORT_SYMBOL(transport_init_session);
247 
248 int transport_alloc_session_tags(struct se_session *se_sess,
249 			         unsigned int tag_num, unsigned int tag_size)
250 {
251 	int rc;
252 
253 	se_sess->sess_cmd_map = kzalloc(tag_num * tag_size,
254 					GFP_KERNEL | __GFP_NOWARN | __GFP_REPEAT);
255 	if (!se_sess->sess_cmd_map) {
256 		se_sess->sess_cmd_map = vzalloc(tag_num * tag_size);
257 		if (!se_sess->sess_cmd_map) {
258 			pr_err("Unable to allocate se_sess->sess_cmd_map\n");
259 			return -ENOMEM;
260 		}
261 	}
262 
263 	rc = percpu_ida_init(&se_sess->sess_tag_pool, tag_num);
264 	if (rc < 0) {
265 		pr_err("Unable to init se_sess->sess_tag_pool,"
266 			" tag_num: %u\n", tag_num);
267 		kvfree(se_sess->sess_cmd_map);
268 		se_sess->sess_cmd_map = NULL;
269 		return -ENOMEM;
270 	}
271 
272 	return 0;
273 }
274 EXPORT_SYMBOL(transport_alloc_session_tags);
275 
276 struct se_session *transport_init_session_tags(unsigned int tag_num,
277 					       unsigned int tag_size,
278 					       enum target_prot_op sup_prot_ops)
279 {
280 	struct se_session *se_sess;
281 	int rc;
282 
283 	if (tag_num != 0 && !tag_size) {
284 		pr_err("init_session_tags called with percpu-ida tag_num:"
285 		       " %u, but zero tag_size\n", tag_num);
286 		return ERR_PTR(-EINVAL);
287 	}
288 	if (!tag_num && tag_size) {
289 		pr_err("init_session_tags called with percpu-ida tag_size:"
290 		       " %u, but zero tag_num\n", tag_size);
291 		return ERR_PTR(-EINVAL);
292 	}
293 
294 	se_sess = transport_init_session(sup_prot_ops);
295 	if (IS_ERR(se_sess))
296 		return se_sess;
297 
298 	rc = transport_alloc_session_tags(se_sess, tag_num, tag_size);
299 	if (rc < 0) {
300 		transport_free_session(se_sess);
301 		return ERR_PTR(-ENOMEM);
302 	}
303 
304 	return se_sess;
305 }
306 EXPORT_SYMBOL(transport_init_session_tags);
307 
308 /*
309  * Called with spin_lock_irqsave(&struct se_portal_group->session_lock called.
310  */
311 void __transport_register_session(
312 	struct se_portal_group *se_tpg,
313 	struct se_node_acl *se_nacl,
314 	struct se_session *se_sess,
315 	void *fabric_sess_ptr)
316 {
317 	const struct target_core_fabric_ops *tfo = se_tpg->se_tpg_tfo;
318 	unsigned char buf[PR_REG_ISID_LEN];
319 
320 	se_sess->se_tpg = se_tpg;
321 	se_sess->fabric_sess_ptr = fabric_sess_ptr;
322 	/*
323 	 * Used by struct se_node_acl's under ConfigFS to locate active se_session-t
324 	 *
325 	 * Only set for struct se_session's that will actually be moving I/O.
326 	 * eg: *NOT* discovery sessions.
327 	 */
328 	if (se_nacl) {
329 		/*
330 		 *
331 		 * Determine if fabric allows for T10-PI feature bits exposed to
332 		 * initiators for device backends with !dev->dev_attrib.pi_prot_type.
333 		 *
334 		 * If so, then always save prot_type on a per se_node_acl node
335 		 * basis and re-instate the previous sess_prot_type to avoid
336 		 * disabling PI from below any previously initiator side
337 		 * registered LUNs.
338 		 */
339 		if (se_nacl->saved_prot_type)
340 			se_sess->sess_prot_type = se_nacl->saved_prot_type;
341 		else if (tfo->tpg_check_prot_fabric_only)
342 			se_sess->sess_prot_type = se_nacl->saved_prot_type =
343 					tfo->tpg_check_prot_fabric_only(se_tpg);
344 		/*
345 		 * If the fabric module supports an ISID based TransportID,
346 		 * save this value in binary from the fabric I_T Nexus now.
347 		 */
348 		if (se_tpg->se_tpg_tfo->sess_get_initiator_sid != NULL) {
349 			memset(&buf[0], 0, PR_REG_ISID_LEN);
350 			se_tpg->se_tpg_tfo->sess_get_initiator_sid(se_sess,
351 					&buf[0], PR_REG_ISID_LEN);
352 			se_sess->sess_bin_isid = get_unaligned_be64(&buf[0]);
353 		}
354 
355 		spin_lock_irq(&se_nacl->nacl_sess_lock);
356 		/*
357 		 * The se_nacl->nacl_sess pointer will be set to the
358 		 * last active I_T Nexus for each struct se_node_acl.
359 		 */
360 		se_nacl->nacl_sess = se_sess;
361 
362 		list_add_tail(&se_sess->sess_acl_list,
363 			      &se_nacl->acl_sess_list);
364 		spin_unlock_irq(&se_nacl->nacl_sess_lock);
365 	}
366 	list_add_tail(&se_sess->sess_list, &se_tpg->tpg_sess_list);
367 
368 	pr_debug("TARGET_CORE[%s]: Registered fabric_sess_ptr: %p\n",
369 		se_tpg->se_tpg_tfo->get_fabric_name(), se_sess->fabric_sess_ptr);
370 }
371 EXPORT_SYMBOL(__transport_register_session);
372 
373 void transport_register_session(
374 	struct se_portal_group *se_tpg,
375 	struct se_node_acl *se_nacl,
376 	struct se_session *se_sess,
377 	void *fabric_sess_ptr)
378 {
379 	unsigned long flags;
380 
381 	spin_lock_irqsave(&se_tpg->session_lock, flags);
382 	__transport_register_session(se_tpg, se_nacl, se_sess, fabric_sess_ptr);
383 	spin_unlock_irqrestore(&se_tpg->session_lock, flags);
384 }
385 EXPORT_SYMBOL(transport_register_session);
386 
387 struct se_session *
388 target_alloc_session(struct se_portal_group *tpg,
389 		     unsigned int tag_num, unsigned int tag_size,
390 		     enum target_prot_op prot_op,
391 		     const char *initiatorname, void *private,
392 		     int (*callback)(struct se_portal_group *,
393 				     struct se_session *, void *))
394 {
395 	struct se_session *sess;
396 
397 	/*
398 	 * If the fabric driver is using percpu-ida based pre allocation
399 	 * of I/O descriptor tags, go ahead and perform that setup now..
400 	 */
401 	if (tag_num != 0)
402 		sess = transport_init_session_tags(tag_num, tag_size, prot_op);
403 	else
404 		sess = transport_init_session(prot_op);
405 
406 	if (IS_ERR(sess))
407 		return sess;
408 
409 	sess->se_node_acl = core_tpg_check_initiator_node_acl(tpg,
410 					(unsigned char *)initiatorname);
411 	if (!sess->se_node_acl) {
412 		transport_free_session(sess);
413 		return ERR_PTR(-EACCES);
414 	}
415 	/*
416 	 * Go ahead and perform any remaining fabric setup that is
417 	 * required before transport_register_session().
418 	 */
419 	if (callback != NULL) {
420 		int rc = callback(tpg, sess, private);
421 		if (rc) {
422 			transport_free_session(sess);
423 			return ERR_PTR(rc);
424 		}
425 	}
426 
427 	transport_register_session(tpg, sess->se_node_acl, sess, private);
428 	return sess;
429 }
430 EXPORT_SYMBOL(target_alloc_session);
431 
432 ssize_t target_show_dynamic_sessions(struct se_portal_group *se_tpg, char *page)
433 {
434 	struct se_session *se_sess;
435 	ssize_t len = 0;
436 
437 	spin_lock_bh(&se_tpg->session_lock);
438 	list_for_each_entry(se_sess, &se_tpg->tpg_sess_list, sess_list) {
439 		if (!se_sess->se_node_acl)
440 			continue;
441 		if (!se_sess->se_node_acl->dynamic_node_acl)
442 			continue;
443 		if (strlen(se_sess->se_node_acl->initiatorname) + 1 + len > PAGE_SIZE)
444 			break;
445 
446 		len += snprintf(page + len, PAGE_SIZE - len, "%s\n",
447 				se_sess->se_node_acl->initiatorname);
448 		len += 1; /* Include NULL terminator */
449 	}
450 	spin_unlock_bh(&se_tpg->session_lock);
451 
452 	return len;
453 }
454 EXPORT_SYMBOL(target_show_dynamic_sessions);
455 
456 static void target_complete_nacl(struct kref *kref)
457 {
458 	struct se_node_acl *nacl = container_of(kref,
459 				struct se_node_acl, acl_kref);
460 	struct se_portal_group *se_tpg = nacl->se_tpg;
461 
462 	if (!nacl->dynamic_stop) {
463 		complete(&nacl->acl_free_comp);
464 		return;
465 	}
466 
467 	mutex_lock(&se_tpg->acl_node_mutex);
468 	list_del(&nacl->acl_list);
469 	mutex_unlock(&se_tpg->acl_node_mutex);
470 
471 	core_tpg_wait_for_nacl_pr_ref(nacl);
472 	core_free_device_list_for_node(nacl, se_tpg);
473 	kfree(nacl);
474 }
475 
476 void target_put_nacl(struct se_node_acl *nacl)
477 {
478 	kref_put(&nacl->acl_kref, target_complete_nacl);
479 }
480 EXPORT_SYMBOL(target_put_nacl);
481 
482 void transport_deregister_session_configfs(struct se_session *se_sess)
483 {
484 	struct se_node_acl *se_nacl;
485 	unsigned long flags;
486 	/*
487 	 * Used by struct se_node_acl's under ConfigFS to locate active struct se_session
488 	 */
489 	se_nacl = se_sess->se_node_acl;
490 	if (se_nacl) {
491 		spin_lock_irqsave(&se_nacl->nacl_sess_lock, flags);
492 		if (!list_empty(&se_sess->sess_acl_list))
493 			list_del_init(&se_sess->sess_acl_list);
494 		/*
495 		 * If the session list is empty, then clear the pointer.
496 		 * Otherwise, set the struct se_session pointer from the tail
497 		 * element of the per struct se_node_acl active session list.
498 		 */
499 		if (list_empty(&se_nacl->acl_sess_list))
500 			se_nacl->nacl_sess = NULL;
501 		else {
502 			se_nacl->nacl_sess = container_of(
503 					se_nacl->acl_sess_list.prev,
504 					struct se_session, sess_acl_list);
505 		}
506 		spin_unlock_irqrestore(&se_nacl->nacl_sess_lock, flags);
507 	}
508 }
509 EXPORT_SYMBOL(transport_deregister_session_configfs);
510 
511 void transport_free_session(struct se_session *se_sess)
512 {
513 	struct se_node_acl *se_nacl = se_sess->se_node_acl;
514 
515 	/*
516 	 * Drop the se_node_acl->nacl_kref obtained from within
517 	 * core_tpg_get_initiator_node_acl().
518 	 */
519 	if (se_nacl) {
520 		struct se_portal_group *se_tpg = se_nacl->se_tpg;
521 		const struct target_core_fabric_ops *se_tfo = se_tpg->se_tpg_tfo;
522 		unsigned long flags;
523 
524 		se_sess->se_node_acl = NULL;
525 
526 		/*
527 		 * Also determine if we need to drop the extra ->cmd_kref if
528 		 * it had been previously dynamically generated, and
529 		 * the endpoint is not caching dynamic ACLs.
530 		 */
531 		mutex_lock(&se_tpg->acl_node_mutex);
532 		if (se_nacl->dynamic_node_acl &&
533 		    !se_tfo->tpg_check_demo_mode_cache(se_tpg)) {
534 			spin_lock_irqsave(&se_nacl->nacl_sess_lock, flags);
535 			if (list_empty(&se_nacl->acl_sess_list))
536 				se_nacl->dynamic_stop = true;
537 			spin_unlock_irqrestore(&se_nacl->nacl_sess_lock, flags);
538 
539 			if (se_nacl->dynamic_stop)
540 				list_del(&se_nacl->acl_list);
541 		}
542 		mutex_unlock(&se_tpg->acl_node_mutex);
543 
544 		if (se_nacl->dynamic_stop)
545 			target_put_nacl(se_nacl);
546 
547 		target_put_nacl(se_nacl);
548 	}
549 	if (se_sess->sess_cmd_map) {
550 		percpu_ida_destroy(&se_sess->sess_tag_pool);
551 		kvfree(se_sess->sess_cmd_map);
552 	}
553 	kmem_cache_free(se_sess_cache, se_sess);
554 }
555 EXPORT_SYMBOL(transport_free_session);
556 
557 void transport_deregister_session(struct se_session *se_sess)
558 {
559 	struct se_portal_group *se_tpg = se_sess->se_tpg;
560 	unsigned long flags;
561 
562 	if (!se_tpg) {
563 		transport_free_session(se_sess);
564 		return;
565 	}
566 
567 	spin_lock_irqsave(&se_tpg->session_lock, flags);
568 	list_del(&se_sess->sess_list);
569 	se_sess->se_tpg = NULL;
570 	se_sess->fabric_sess_ptr = NULL;
571 	spin_unlock_irqrestore(&se_tpg->session_lock, flags);
572 
573 	pr_debug("TARGET_CORE[%s]: Deregistered fabric_sess\n",
574 		se_tpg->se_tpg_tfo->get_fabric_name());
575 	/*
576 	 * If last kref is dropping now for an explicit NodeACL, awake sleeping
577 	 * ->acl_free_comp caller to wakeup configfs se_node_acl->acl_group
578 	 * removal context from within transport_free_session() code.
579 	 *
580 	 * For dynamic ACL, target_put_nacl() uses target_complete_nacl()
581 	 * to release all remaining generate_node_acl=1 created ACL resources.
582 	 */
583 
584 	transport_free_session(se_sess);
585 }
586 EXPORT_SYMBOL(transport_deregister_session);
587 
588 static void target_remove_from_state_list(struct se_cmd *cmd)
589 {
590 	struct se_device *dev = cmd->se_dev;
591 	unsigned long flags;
592 
593 	if (!dev)
594 		return;
595 
596 	spin_lock_irqsave(&dev->execute_task_lock, flags);
597 	if (cmd->state_active) {
598 		list_del(&cmd->state_list);
599 		cmd->state_active = false;
600 	}
601 	spin_unlock_irqrestore(&dev->execute_task_lock, flags);
602 }
603 
604 static int transport_cmd_check_stop_to_fabric(struct se_cmd *cmd)
605 {
606 	unsigned long flags;
607 
608 	target_remove_from_state_list(cmd);
609 
610 	/*
611 	 * Clear struct se_cmd->se_lun before the handoff to FE.
612 	 */
613 	cmd->se_lun = NULL;
614 
615 	spin_lock_irqsave(&cmd->t_state_lock, flags);
616 	/*
617 	 * Determine if frontend context caller is requesting the stopping of
618 	 * this command for frontend exceptions.
619 	 */
620 	if (cmd->transport_state & CMD_T_STOP) {
621 		pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08llx\n",
622 			__func__, __LINE__, cmd->tag);
623 
624 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
625 
626 		complete_all(&cmd->t_transport_stop_comp);
627 		return 1;
628 	}
629 	cmd->transport_state &= ~CMD_T_ACTIVE;
630 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
631 
632 	/*
633 	 * Some fabric modules like tcm_loop can release their internally
634 	 * allocated I/O reference and struct se_cmd now.
635 	 *
636 	 * Fabric modules are expected to return '1' here if the se_cmd being
637 	 * passed is released at this point, or zero if not being released.
638 	 */
639 	return cmd->se_tfo->check_stop_free ? cmd->se_tfo->check_stop_free(cmd)
640 		: 0;
641 }
642 
643 static void transport_lun_remove_cmd(struct se_cmd *cmd)
644 {
645 	struct se_lun *lun = cmd->se_lun;
646 
647 	if (!lun)
648 		return;
649 
650 	if (cmpxchg(&cmd->lun_ref_active, true, false))
651 		percpu_ref_put(&lun->lun_ref);
652 }
653 
654 void transport_cmd_finish_abort(struct se_cmd *cmd, int remove)
655 {
656 	bool ack_kref = (cmd->se_cmd_flags & SCF_ACK_KREF);
657 
658 	if (cmd->se_cmd_flags & SCF_SE_LUN_CMD)
659 		transport_lun_remove_cmd(cmd);
660 	/*
661 	 * Allow the fabric driver to unmap any resources before
662 	 * releasing the descriptor via TFO->release_cmd()
663 	 */
664 	if (remove)
665 		cmd->se_tfo->aborted_task(cmd);
666 
667 	if (transport_cmd_check_stop_to_fabric(cmd))
668 		return;
669 	if (remove && ack_kref)
670 		transport_put_cmd(cmd);
671 }
672 
673 static void target_complete_failure_work(struct work_struct *work)
674 {
675 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
676 
677 	transport_generic_request_failure(cmd,
678 			TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE);
679 }
680 
681 /*
682  * Used when asking transport to copy Sense Data from the underlying
683  * Linux/SCSI struct scsi_cmnd
684  */
685 static unsigned char *transport_get_sense_buffer(struct se_cmd *cmd)
686 {
687 	struct se_device *dev = cmd->se_dev;
688 
689 	WARN_ON(!cmd->se_lun);
690 
691 	if (!dev)
692 		return NULL;
693 
694 	if (cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION)
695 		return NULL;
696 
697 	cmd->scsi_sense_length = TRANSPORT_SENSE_BUFFER;
698 
699 	pr_debug("HBA_[%u]_PLUG[%s]: Requesting sense for SAM STATUS: 0x%02x\n",
700 		dev->se_hba->hba_id, dev->transport->name, cmd->scsi_status);
701 	return cmd->sense_buffer;
702 }
703 
704 void target_complete_cmd(struct se_cmd *cmd, u8 scsi_status)
705 {
706 	struct se_device *dev = cmd->se_dev;
707 	int success = scsi_status == GOOD;
708 	unsigned long flags;
709 
710 	cmd->scsi_status = scsi_status;
711 
712 
713 	spin_lock_irqsave(&cmd->t_state_lock, flags);
714 
715 	if (dev && dev->transport->transport_complete) {
716 		dev->transport->transport_complete(cmd,
717 				cmd->t_data_sg,
718 				transport_get_sense_buffer(cmd));
719 		if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE)
720 			success = 1;
721 	}
722 
723 	/*
724 	 * Check for case where an explicit ABORT_TASK has been received
725 	 * and transport_wait_for_tasks() will be waiting for completion..
726 	 */
727 	if (cmd->transport_state & CMD_T_ABORTED ||
728 	    cmd->transport_state & CMD_T_STOP) {
729 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
730 		complete_all(&cmd->t_transport_stop_comp);
731 		return;
732 	} else if (!success) {
733 		INIT_WORK(&cmd->work, target_complete_failure_work);
734 	} else {
735 		INIT_WORK(&cmd->work, target_complete_ok_work);
736 	}
737 
738 	cmd->t_state = TRANSPORT_COMPLETE;
739 	cmd->transport_state |= (CMD_T_COMPLETE | CMD_T_ACTIVE);
740 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
741 
742 	if (cmd->se_cmd_flags & SCF_USE_CPUID)
743 		queue_work_on(cmd->cpuid, target_completion_wq, &cmd->work);
744 	else
745 		queue_work(target_completion_wq, &cmd->work);
746 }
747 EXPORT_SYMBOL(target_complete_cmd);
748 
749 void target_complete_cmd_with_length(struct se_cmd *cmd, u8 scsi_status, int length)
750 {
751 	if (scsi_status == SAM_STAT_GOOD && length < cmd->data_length) {
752 		if (cmd->se_cmd_flags & SCF_UNDERFLOW_BIT) {
753 			cmd->residual_count += cmd->data_length - length;
754 		} else {
755 			cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
756 			cmd->residual_count = cmd->data_length - length;
757 		}
758 
759 		cmd->data_length = length;
760 	}
761 
762 	target_complete_cmd(cmd, scsi_status);
763 }
764 EXPORT_SYMBOL(target_complete_cmd_with_length);
765 
766 static void target_add_to_state_list(struct se_cmd *cmd)
767 {
768 	struct se_device *dev = cmd->se_dev;
769 	unsigned long flags;
770 
771 	spin_lock_irqsave(&dev->execute_task_lock, flags);
772 	if (!cmd->state_active) {
773 		list_add_tail(&cmd->state_list, &dev->state_list);
774 		cmd->state_active = true;
775 	}
776 	spin_unlock_irqrestore(&dev->execute_task_lock, flags);
777 }
778 
779 /*
780  * Handle QUEUE_FULL / -EAGAIN and -ENOMEM status
781  */
782 static void transport_write_pending_qf(struct se_cmd *cmd);
783 static void transport_complete_qf(struct se_cmd *cmd);
784 
785 void target_qf_do_work(struct work_struct *work)
786 {
787 	struct se_device *dev = container_of(work, struct se_device,
788 					qf_work_queue);
789 	LIST_HEAD(qf_cmd_list);
790 	struct se_cmd *cmd, *cmd_tmp;
791 
792 	spin_lock_irq(&dev->qf_cmd_lock);
793 	list_splice_init(&dev->qf_cmd_list, &qf_cmd_list);
794 	spin_unlock_irq(&dev->qf_cmd_lock);
795 
796 	list_for_each_entry_safe(cmd, cmd_tmp, &qf_cmd_list, se_qf_node) {
797 		list_del(&cmd->se_qf_node);
798 		atomic_dec_mb(&dev->dev_qf_count);
799 
800 		pr_debug("Processing %s cmd: %p QUEUE_FULL in work queue"
801 			" context: %s\n", cmd->se_tfo->get_fabric_name(), cmd,
802 			(cmd->t_state == TRANSPORT_COMPLETE_QF_OK) ? "COMPLETE_OK" :
803 			(cmd->t_state == TRANSPORT_COMPLETE_QF_WP) ? "WRITE_PENDING"
804 			: "UNKNOWN");
805 
806 		if (cmd->t_state == TRANSPORT_COMPLETE_QF_WP)
807 			transport_write_pending_qf(cmd);
808 		else if (cmd->t_state == TRANSPORT_COMPLETE_QF_OK)
809 			transport_complete_qf(cmd);
810 	}
811 }
812 
813 unsigned char *transport_dump_cmd_direction(struct se_cmd *cmd)
814 {
815 	switch (cmd->data_direction) {
816 	case DMA_NONE:
817 		return "NONE";
818 	case DMA_FROM_DEVICE:
819 		return "READ";
820 	case DMA_TO_DEVICE:
821 		return "WRITE";
822 	case DMA_BIDIRECTIONAL:
823 		return "BIDI";
824 	default:
825 		break;
826 	}
827 
828 	return "UNKNOWN";
829 }
830 
831 void transport_dump_dev_state(
832 	struct se_device *dev,
833 	char *b,
834 	int *bl)
835 {
836 	*bl += sprintf(b + *bl, "Status: ");
837 	if (dev->export_count)
838 		*bl += sprintf(b + *bl, "ACTIVATED");
839 	else
840 		*bl += sprintf(b + *bl, "DEACTIVATED");
841 
842 	*bl += sprintf(b + *bl, "  Max Queue Depth: %d", dev->queue_depth);
843 	*bl += sprintf(b + *bl, "  SectorSize: %u  HwMaxSectors: %u\n",
844 		dev->dev_attrib.block_size,
845 		dev->dev_attrib.hw_max_sectors);
846 	*bl += sprintf(b + *bl, "        ");
847 }
848 
849 void transport_dump_vpd_proto_id(
850 	struct t10_vpd *vpd,
851 	unsigned char *p_buf,
852 	int p_buf_len)
853 {
854 	unsigned char buf[VPD_TMP_BUF_SIZE];
855 	int len;
856 
857 	memset(buf, 0, VPD_TMP_BUF_SIZE);
858 	len = sprintf(buf, "T10 VPD Protocol Identifier: ");
859 
860 	switch (vpd->protocol_identifier) {
861 	case 0x00:
862 		sprintf(buf+len, "Fibre Channel\n");
863 		break;
864 	case 0x10:
865 		sprintf(buf+len, "Parallel SCSI\n");
866 		break;
867 	case 0x20:
868 		sprintf(buf+len, "SSA\n");
869 		break;
870 	case 0x30:
871 		sprintf(buf+len, "IEEE 1394\n");
872 		break;
873 	case 0x40:
874 		sprintf(buf+len, "SCSI Remote Direct Memory Access"
875 				" Protocol\n");
876 		break;
877 	case 0x50:
878 		sprintf(buf+len, "Internet SCSI (iSCSI)\n");
879 		break;
880 	case 0x60:
881 		sprintf(buf+len, "SAS Serial SCSI Protocol\n");
882 		break;
883 	case 0x70:
884 		sprintf(buf+len, "Automation/Drive Interface Transport"
885 				" Protocol\n");
886 		break;
887 	case 0x80:
888 		sprintf(buf+len, "AT Attachment Interface ATA/ATAPI\n");
889 		break;
890 	default:
891 		sprintf(buf+len, "Unknown 0x%02x\n",
892 				vpd->protocol_identifier);
893 		break;
894 	}
895 
896 	if (p_buf)
897 		strncpy(p_buf, buf, p_buf_len);
898 	else
899 		pr_debug("%s", buf);
900 }
901 
902 void
903 transport_set_vpd_proto_id(struct t10_vpd *vpd, unsigned char *page_83)
904 {
905 	/*
906 	 * Check if the Protocol Identifier Valid (PIV) bit is set..
907 	 *
908 	 * from spc3r23.pdf section 7.5.1
909 	 */
910 	 if (page_83[1] & 0x80) {
911 		vpd->protocol_identifier = (page_83[0] & 0xf0);
912 		vpd->protocol_identifier_set = 1;
913 		transport_dump_vpd_proto_id(vpd, NULL, 0);
914 	}
915 }
916 EXPORT_SYMBOL(transport_set_vpd_proto_id);
917 
918 int transport_dump_vpd_assoc(
919 	struct t10_vpd *vpd,
920 	unsigned char *p_buf,
921 	int p_buf_len)
922 {
923 	unsigned char buf[VPD_TMP_BUF_SIZE];
924 	int ret = 0;
925 	int len;
926 
927 	memset(buf, 0, VPD_TMP_BUF_SIZE);
928 	len = sprintf(buf, "T10 VPD Identifier Association: ");
929 
930 	switch (vpd->association) {
931 	case 0x00:
932 		sprintf(buf+len, "addressed logical unit\n");
933 		break;
934 	case 0x10:
935 		sprintf(buf+len, "target port\n");
936 		break;
937 	case 0x20:
938 		sprintf(buf+len, "SCSI target device\n");
939 		break;
940 	default:
941 		sprintf(buf+len, "Unknown 0x%02x\n", vpd->association);
942 		ret = -EINVAL;
943 		break;
944 	}
945 
946 	if (p_buf)
947 		strncpy(p_buf, buf, p_buf_len);
948 	else
949 		pr_debug("%s", buf);
950 
951 	return ret;
952 }
953 
954 int transport_set_vpd_assoc(struct t10_vpd *vpd, unsigned char *page_83)
955 {
956 	/*
957 	 * The VPD identification association..
958 	 *
959 	 * from spc3r23.pdf Section 7.6.3.1 Table 297
960 	 */
961 	vpd->association = (page_83[1] & 0x30);
962 	return transport_dump_vpd_assoc(vpd, NULL, 0);
963 }
964 EXPORT_SYMBOL(transport_set_vpd_assoc);
965 
966 int transport_dump_vpd_ident_type(
967 	struct t10_vpd *vpd,
968 	unsigned char *p_buf,
969 	int p_buf_len)
970 {
971 	unsigned char buf[VPD_TMP_BUF_SIZE];
972 	int ret = 0;
973 	int len;
974 
975 	memset(buf, 0, VPD_TMP_BUF_SIZE);
976 	len = sprintf(buf, "T10 VPD Identifier Type: ");
977 
978 	switch (vpd->device_identifier_type) {
979 	case 0x00:
980 		sprintf(buf+len, "Vendor specific\n");
981 		break;
982 	case 0x01:
983 		sprintf(buf+len, "T10 Vendor ID based\n");
984 		break;
985 	case 0x02:
986 		sprintf(buf+len, "EUI-64 based\n");
987 		break;
988 	case 0x03:
989 		sprintf(buf+len, "NAA\n");
990 		break;
991 	case 0x04:
992 		sprintf(buf+len, "Relative target port identifier\n");
993 		break;
994 	case 0x08:
995 		sprintf(buf+len, "SCSI name string\n");
996 		break;
997 	default:
998 		sprintf(buf+len, "Unsupported: 0x%02x\n",
999 				vpd->device_identifier_type);
1000 		ret = -EINVAL;
1001 		break;
1002 	}
1003 
1004 	if (p_buf) {
1005 		if (p_buf_len < strlen(buf)+1)
1006 			return -EINVAL;
1007 		strncpy(p_buf, buf, p_buf_len);
1008 	} else {
1009 		pr_debug("%s", buf);
1010 	}
1011 
1012 	return ret;
1013 }
1014 
1015 int transport_set_vpd_ident_type(struct t10_vpd *vpd, unsigned char *page_83)
1016 {
1017 	/*
1018 	 * The VPD identifier type..
1019 	 *
1020 	 * from spc3r23.pdf Section 7.6.3.1 Table 298
1021 	 */
1022 	vpd->device_identifier_type = (page_83[1] & 0x0f);
1023 	return transport_dump_vpd_ident_type(vpd, NULL, 0);
1024 }
1025 EXPORT_SYMBOL(transport_set_vpd_ident_type);
1026 
1027 int transport_dump_vpd_ident(
1028 	struct t10_vpd *vpd,
1029 	unsigned char *p_buf,
1030 	int p_buf_len)
1031 {
1032 	unsigned char buf[VPD_TMP_BUF_SIZE];
1033 	int ret = 0;
1034 
1035 	memset(buf, 0, VPD_TMP_BUF_SIZE);
1036 
1037 	switch (vpd->device_identifier_code_set) {
1038 	case 0x01: /* Binary */
1039 		snprintf(buf, sizeof(buf),
1040 			"T10 VPD Binary Device Identifier: %s\n",
1041 			&vpd->device_identifier[0]);
1042 		break;
1043 	case 0x02: /* ASCII */
1044 		snprintf(buf, sizeof(buf),
1045 			"T10 VPD ASCII Device Identifier: %s\n",
1046 			&vpd->device_identifier[0]);
1047 		break;
1048 	case 0x03: /* UTF-8 */
1049 		snprintf(buf, sizeof(buf),
1050 			"T10 VPD UTF-8 Device Identifier: %s\n",
1051 			&vpd->device_identifier[0]);
1052 		break;
1053 	default:
1054 		sprintf(buf, "T10 VPD Device Identifier encoding unsupported:"
1055 			" 0x%02x", vpd->device_identifier_code_set);
1056 		ret = -EINVAL;
1057 		break;
1058 	}
1059 
1060 	if (p_buf)
1061 		strncpy(p_buf, buf, p_buf_len);
1062 	else
1063 		pr_debug("%s", buf);
1064 
1065 	return ret;
1066 }
1067 
1068 int
1069 transport_set_vpd_ident(struct t10_vpd *vpd, unsigned char *page_83)
1070 {
1071 	static const char hex_str[] = "0123456789abcdef";
1072 	int j = 0, i = 4; /* offset to start of the identifier */
1073 
1074 	/*
1075 	 * The VPD Code Set (encoding)
1076 	 *
1077 	 * from spc3r23.pdf Section 7.6.3.1 Table 296
1078 	 */
1079 	vpd->device_identifier_code_set = (page_83[0] & 0x0f);
1080 	switch (vpd->device_identifier_code_set) {
1081 	case 0x01: /* Binary */
1082 		vpd->device_identifier[j++] =
1083 				hex_str[vpd->device_identifier_type];
1084 		while (i < (4 + page_83[3])) {
1085 			vpd->device_identifier[j++] =
1086 				hex_str[(page_83[i] & 0xf0) >> 4];
1087 			vpd->device_identifier[j++] =
1088 				hex_str[page_83[i] & 0x0f];
1089 			i++;
1090 		}
1091 		break;
1092 	case 0x02: /* ASCII */
1093 	case 0x03: /* UTF-8 */
1094 		while (i < (4 + page_83[3]))
1095 			vpd->device_identifier[j++] = page_83[i++];
1096 		break;
1097 	default:
1098 		break;
1099 	}
1100 
1101 	return transport_dump_vpd_ident(vpd, NULL, 0);
1102 }
1103 EXPORT_SYMBOL(transport_set_vpd_ident);
1104 
1105 static sense_reason_t
1106 target_check_max_data_sg_nents(struct se_cmd *cmd, struct se_device *dev,
1107 			       unsigned int size)
1108 {
1109 	u32 mtl;
1110 
1111 	if (!cmd->se_tfo->max_data_sg_nents)
1112 		return TCM_NO_SENSE;
1113 	/*
1114 	 * Check if fabric enforced maximum SGL entries per I/O descriptor
1115 	 * exceeds se_cmd->data_length.  If true, set SCF_UNDERFLOW_BIT +
1116 	 * residual_count and reduce original cmd->data_length to maximum
1117 	 * length based on single PAGE_SIZE entry scatter-lists.
1118 	 */
1119 	mtl = (cmd->se_tfo->max_data_sg_nents * PAGE_SIZE);
1120 	if (cmd->data_length > mtl) {
1121 		/*
1122 		 * If an existing CDB overflow is present, calculate new residual
1123 		 * based on CDB size minus fabric maximum transfer length.
1124 		 *
1125 		 * If an existing CDB underflow is present, calculate new residual
1126 		 * based on original cmd->data_length minus fabric maximum transfer
1127 		 * length.
1128 		 *
1129 		 * Otherwise, set the underflow residual based on cmd->data_length
1130 		 * minus fabric maximum transfer length.
1131 		 */
1132 		if (cmd->se_cmd_flags & SCF_OVERFLOW_BIT) {
1133 			cmd->residual_count = (size - mtl);
1134 		} else if (cmd->se_cmd_flags & SCF_UNDERFLOW_BIT) {
1135 			u32 orig_dl = size + cmd->residual_count;
1136 			cmd->residual_count = (orig_dl - mtl);
1137 		} else {
1138 			cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
1139 			cmd->residual_count = (cmd->data_length - mtl);
1140 		}
1141 		cmd->data_length = mtl;
1142 		/*
1143 		 * Reset sbc_check_prot() calculated protection payload
1144 		 * length based upon the new smaller MTL.
1145 		 */
1146 		if (cmd->prot_length) {
1147 			u32 sectors = (mtl / dev->dev_attrib.block_size);
1148 			cmd->prot_length = dev->prot_length * sectors;
1149 		}
1150 	}
1151 	return TCM_NO_SENSE;
1152 }
1153 
1154 sense_reason_t
1155 target_cmd_size_check(struct se_cmd *cmd, unsigned int size)
1156 {
1157 	struct se_device *dev = cmd->se_dev;
1158 
1159 	if (cmd->unknown_data_length) {
1160 		cmd->data_length = size;
1161 	} else if (size != cmd->data_length) {
1162 		pr_warn("TARGET_CORE[%s]: Expected Transfer Length:"
1163 			" %u does not match SCSI CDB Length: %u for SAM Opcode:"
1164 			" 0x%02x\n", cmd->se_tfo->get_fabric_name(),
1165 				cmd->data_length, size, cmd->t_task_cdb[0]);
1166 
1167 		if (cmd->data_direction == DMA_TO_DEVICE &&
1168 		    cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) {
1169 			pr_err("Rejecting underflow/overflow WRITE data\n");
1170 			return TCM_INVALID_CDB_FIELD;
1171 		}
1172 		/*
1173 		 * Reject READ_* or WRITE_* with overflow/underflow for
1174 		 * type SCF_SCSI_DATA_CDB.
1175 		 */
1176 		if (dev->dev_attrib.block_size != 512)  {
1177 			pr_err("Failing OVERFLOW/UNDERFLOW for LBA op"
1178 				" CDB on non 512-byte sector setup subsystem"
1179 				" plugin: %s\n", dev->transport->name);
1180 			/* Returns CHECK_CONDITION + INVALID_CDB_FIELD */
1181 			return TCM_INVALID_CDB_FIELD;
1182 		}
1183 		/*
1184 		 * For the overflow case keep the existing fabric provided
1185 		 * ->data_length.  Otherwise for the underflow case, reset
1186 		 * ->data_length to the smaller SCSI expected data transfer
1187 		 * length.
1188 		 */
1189 		if (size > cmd->data_length) {
1190 			cmd->se_cmd_flags |= SCF_OVERFLOW_BIT;
1191 			cmd->residual_count = (size - cmd->data_length);
1192 		} else {
1193 			cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
1194 			cmd->residual_count = (cmd->data_length - size);
1195 			cmd->data_length = size;
1196 		}
1197 	}
1198 
1199 	return target_check_max_data_sg_nents(cmd, dev, size);
1200 
1201 }
1202 
1203 /*
1204  * Used by fabric modules containing a local struct se_cmd within their
1205  * fabric dependent per I/O descriptor.
1206  *
1207  * Preserves the value of @cmd->tag.
1208  */
1209 void transport_init_se_cmd(
1210 	struct se_cmd *cmd,
1211 	const struct target_core_fabric_ops *tfo,
1212 	struct se_session *se_sess,
1213 	u32 data_length,
1214 	int data_direction,
1215 	int task_attr,
1216 	unsigned char *sense_buffer)
1217 {
1218 	INIT_LIST_HEAD(&cmd->se_delayed_node);
1219 	INIT_LIST_HEAD(&cmd->se_qf_node);
1220 	INIT_LIST_HEAD(&cmd->se_cmd_list);
1221 	INIT_LIST_HEAD(&cmd->state_list);
1222 	init_completion(&cmd->t_transport_stop_comp);
1223 	init_completion(&cmd->cmd_wait_comp);
1224 	spin_lock_init(&cmd->t_state_lock);
1225 	kref_init(&cmd->cmd_kref);
1226 
1227 	cmd->se_tfo = tfo;
1228 	cmd->se_sess = se_sess;
1229 	cmd->data_length = data_length;
1230 	cmd->data_direction = data_direction;
1231 	cmd->sam_task_attr = task_attr;
1232 	cmd->sense_buffer = sense_buffer;
1233 
1234 	cmd->state_active = false;
1235 }
1236 EXPORT_SYMBOL(transport_init_se_cmd);
1237 
1238 static sense_reason_t
1239 transport_check_alloc_task_attr(struct se_cmd *cmd)
1240 {
1241 	struct se_device *dev = cmd->se_dev;
1242 
1243 	/*
1244 	 * Check if SAM Task Attribute emulation is enabled for this
1245 	 * struct se_device storage object
1246 	 */
1247 	if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
1248 		return 0;
1249 
1250 	if (cmd->sam_task_attr == TCM_ACA_TAG) {
1251 		pr_debug("SAM Task Attribute ACA"
1252 			" emulation is not supported\n");
1253 		return TCM_INVALID_CDB_FIELD;
1254 	}
1255 
1256 	return 0;
1257 }
1258 
1259 sense_reason_t
1260 target_setup_cmd_from_cdb(struct se_cmd *cmd, unsigned char *cdb)
1261 {
1262 	struct se_device *dev = cmd->se_dev;
1263 	sense_reason_t ret;
1264 
1265 	/*
1266 	 * Ensure that the received CDB is less than the max (252 + 8) bytes
1267 	 * for VARIABLE_LENGTH_CMD
1268 	 */
1269 	if (scsi_command_size(cdb) > SCSI_MAX_VARLEN_CDB_SIZE) {
1270 		pr_err("Received SCSI CDB with command_size: %d that"
1271 			" exceeds SCSI_MAX_VARLEN_CDB_SIZE: %d\n",
1272 			scsi_command_size(cdb), SCSI_MAX_VARLEN_CDB_SIZE);
1273 		return TCM_INVALID_CDB_FIELD;
1274 	}
1275 	/*
1276 	 * If the received CDB is larger than TCM_MAX_COMMAND_SIZE,
1277 	 * allocate the additional extended CDB buffer now..  Otherwise
1278 	 * setup the pointer from __t_task_cdb to t_task_cdb.
1279 	 */
1280 	if (scsi_command_size(cdb) > sizeof(cmd->__t_task_cdb)) {
1281 		cmd->t_task_cdb = kzalloc(scsi_command_size(cdb),
1282 						GFP_KERNEL);
1283 		if (!cmd->t_task_cdb) {
1284 			pr_err("Unable to allocate cmd->t_task_cdb"
1285 				" %u > sizeof(cmd->__t_task_cdb): %lu ops\n",
1286 				scsi_command_size(cdb),
1287 				(unsigned long)sizeof(cmd->__t_task_cdb));
1288 			return TCM_OUT_OF_RESOURCES;
1289 		}
1290 	} else
1291 		cmd->t_task_cdb = &cmd->__t_task_cdb[0];
1292 	/*
1293 	 * Copy the original CDB into cmd->
1294 	 */
1295 	memcpy(cmd->t_task_cdb, cdb, scsi_command_size(cdb));
1296 
1297 	trace_target_sequencer_start(cmd);
1298 
1299 	ret = dev->transport->parse_cdb(cmd);
1300 	if (ret == TCM_UNSUPPORTED_SCSI_OPCODE)
1301 		pr_warn_ratelimited("%s/%s: Unsupported SCSI Opcode 0x%02x, sending CHECK_CONDITION.\n",
1302 				    cmd->se_tfo->get_fabric_name(),
1303 				    cmd->se_sess->se_node_acl->initiatorname,
1304 				    cmd->t_task_cdb[0]);
1305 	if (ret)
1306 		return ret;
1307 
1308 	ret = transport_check_alloc_task_attr(cmd);
1309 	if (ret)
1310 		return ret;
1311 
1312 	cmd->se_cmd_flags |= SCF_SUPPORTED_SAM_OPCODE;
1313 	atomic_long_inc(&cmd->se_lun->lun_stats.cmd_pdus);
1314 	return 0;
1315 }
1316 EXPORT_SYMBOL(target_setup_cmd_from_cdb);
1317 
1318 /*
1319  * Used by fabric module frontends to queue tasks directly.
1320  * May only be used from process context.
1321  */
1322 int transport_handle_cdb_direct(
1323 	struct se_cmd *cmd)
1324 {
1325 	sense_reason_t ret;
1326 
1327 	if (!cmd->se_lun) {
1328 		dump_stack();
1329 		pr_err("cmd->se_lun is NULL\n");
1330 		return -EINVAL;
1331 	}
1332 	if (in_interrupt()) {
1333 		dump_stack();
1334 		pr_err("transport_generic_handle_cdb cannot be called"
1335 				" from interrupt context\n");
1336 		return -EINVAL;
1337 	}
1338 	/*
1339 	 * Set TRANSPORT_NEW_CMD state and CMD_T_ACTIVE to ensure that
1340 	 * outstanding descriptors are handled correctly during shutdown via
1341 	 * transport_wait_for_tasks()
1342 	 *
1343 	 * Also, we don't take cmd->t_state_lock here as we only expect
1344 	 * this to be called for initial descriptor submission.
1345 	 */
1346 	cmd->t_state = TRANSPORT_NEW_CMD;
1347 	cmd->transport_state |= CMD_T_ACTIVE;
1348 
1349 	/*
1350 	 * transport_generic_new_cmd() is already handling QUEUE_FULL,
1351 	 * so follow TRANSPORT_NEW_CMD processing thread context usage
1352 	 * and call transport_generic_request_failure() if necessary..
1353 	 */
1354 	ret = transport_generic_new_cmd(cmd);
1355 	if (ret)
1356 		transport_generic_request_failure(cmd, ret);
1357 	return 0;
1358 }
1359 EXPORT_SYMBOL(transport_handle_cdb_direct);
1360 
1361 sense_reason_t
1362 transport_generic_map_mem_to_cmd(struct se_cmd *cmd, struct scatterlist *sgl,
1363 		u32 sgl_count, struct scatterlist *sgl_bidi, u32 sgl_bidi_count)
1364 {
1365 	if (!sgl || !sgl_count)
1366 		return 0;
1367 
1368 	/*
1369 	 * Reject SCSI data overflow with map_mem_to_cmd() as incoming
1370 	 * scatterlists already have been set to follow what the fabric
1371 	 * passes for the original expected data transfer length.
1372 	 */
1373 	if (cmd->se_cmd_flags & SCF_OVERFLOW_BIT) {
1374 		pr_warn("Rejecting SCSI DATA overflow for fabric using"
1375 			" SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC\n");
1376 		return TCM_INVALID_CDB_FIELD;
1377 	}
1378 
1379 	cmd->t_data_sg = sgl;
1380 	cmd->t_data_nents = sgl_count;
1381 	cmd->t_bidi_data_sg = sgl_bidi;
1382 	cmd->t_bidi_data_nents = sgl_bidi_count;
1383 
1384 	cmd->se_cmd_flags |= SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC;
1385 	return 0;
1386 }
1387 
1388 /*
1389  * target_submit_cmd_map_sgls - lookup unpacked lun and submit uninitialized
1390  * 			 se_cmd + use pre-allocated SGL memory.
1391  *
1392  * @se_cmd: command descriptor to submit
1393  * @se_sess: associated se_sess for endpoint
1394  * @cdb: pointer to SCSI CDB
1395  * @sense: pointer to SCSI sense buffer
1396  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1397  * @data_length: fabric expected data transfer length
1398  * @task_addr: SAM task attribute
1399  * @data_dir: DMA data direction
1400  * @flags: flags for command submission from target_sc_flags_tables
1401  * @sgl: struct scatterlist memory for unidirectional mapping
1402  * @sgl_count: scatterlist count for unidirectional mapping
1403  * @sgl_bidi: struct scatterlist memory for bidirectional READ mapping
1404  * @sgl_bidi_count: scatterlist count for bidirectional READ mapping
1405  * @sgl_prot: struct scatterlist memory protection information
1406  * @sgl_prot_count: scatterlist count for protection information
1407  *
1408  * Task tags are supported if the caller has set @se_cmd->tag.
1409  *
1410  * Returns non zero to signal active I/O shutdown failure.  All other
1411  * setup exceptions will be returned as a SCSI CHECK_CONDITION response,
1412  * but still return zero here.
1413  *
1414  * This may only be called from process context, and also currently
1415  * assumes internal allocation of fabric payload buffer by target-core.
1416  */
1417 int target_submit_cmd_map_sgls(struct se_cmd *se_cmd, struct se_session *se_sess,
1418 		unsigned char *cdb, unsigned char *sense, u64 unpacked_lun,
1419 		u32 data_length, int task_attr, int data_dir, int flags,
1420 		struct scatterlist *sgl, u32 sgl_count,
1421 		struct scatterlist *sgl_bidi, u32 sgl_bidi_count,
1422 		struct scatterlist *sgl_prot, u32 sgl_prot_count)
1423 {
1424 	struct se_portal_group *se_tpg;
1425 	sense_reason_t rc;
1426 	int ret;
1427 
1428 	se_tpg = se_sess->se_tpg;
1429 	BUG_ON(!se_tpg);
1430 	BUG_ON(se_cmd->se_tfo || se_cmd->se_sess);
1431 	BUG_ON(in_interrupt());
1432 	/*
1433 	 * Initialize se_cmd for target operation.  From this point
1434 	 * exceptions are handled by sending exception status via
1435 	 * target_core_fabric_ops->queue_status() callback
1436 	 */
1437 	transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess,
1438 				data_length, data_dir, task_attr, sense);
1439 
1440 	if (flags & TARGET_SCF_USE_CPUID)
1441 		se_cmd->se_cmd_flags |= SCF_USE_CPUID;
1442 	else
1443 		se_cmd->cpuid = WORK_CPU_UNBOUND;
1444 
1445 	if (flags & TARGET_SCF_UNKNOWN_SIZE)
1446 		se_cmd->unknown_data_length = 1;
1447 	/*
1448 	 * Obtain struct se_cmd->cmd_kref reference and add new cmd to
1449 	 * se_sess->sess_cmd_list.  A second kref_get here is necessary
1450 	 * for fabrics using TARGET_SCF_ACK_KREF that expect a second
1451 	 * kref_put() to happen during fabric packet acknowledgement.
1452 	 */
1453 	ret = target_get_sess_cmd(se_cmd, flags & TARGET_SCF_ACK_KREF);
1454 	if (ret)
1455 		return ret;
1456 	/*
1457 	 * Signal bidirectional data payloads to target-core
1458 	 */
1459 	if (flags & TARGET_SCF_BIDI_OP)
1460 		se_cmd->se_cmd_flags |= SCF_BIDI;
1461 	/*
1462 	 * Locate se_lun pointer and attach it to struct se_cmd
1463 	 */
1464 	rc = transport_lookup_cmd_lun(se_cmd, unpacked_lun);
1465 	if (rc) {
1466 		transport_send_check_condition_and_sense(se_cmd, rc, 0);
1467 		target_put_sess_cmd(se_cmd);
1468 		return 0;
1469 	}
1470 
1471 	rc = target_setup_cmd_from_cdb(se_cmd, cdb);
1472 	if (rc != 0) {
1473 		transport_generic_request_failure(se_cmd, rc);
1474 		return 0;
1475 	}
1476 
1477 	/*
1478 	 * Save pointers for SGLs containing protection information,
1479 	 * if present.
1480 	 */
1481 	if (sgl_prot_count) {
1482 		se_cmd->t_prot_sg = sgl_prot;
1483 		se_cmd->t_prot_nents = sgl_prot_count;
1484 		se_cmd->se_cmd_flags |= SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC;
1485 	}
1486 
1487 	/*
1488 	 * When a non zero sgl_count has been passed perform SGL passthrough
1489 	 * mapping for pre-allocated fabric memory instead of having target
1490 	 * core perform an internal SGL allocation..
1491 	 */
1492 	if (sgl_count != 0) {
1493 		BUG_ON(!sgl);
1494 
1495 		/*
1496 		 * A work-around for tcm_loop as some userspace code via
1497 		 * scsi-generic do not memset their associated read buffers,
1498 		 * so go ahead and do that here for type non-data CDBs.  Also
1499 		 * note that this is currently guaranteed to be a single SGL
1500 		 * for this case by target core in target_setup_cmd_from_cdb()
1501 		 * -> transport_generic_cmd_sequencer().
1502 		 */
1503 		if (!(se_cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) &&
1504 		     se_cmd->data_direction == DMA_FROM_DEVICE) {
1505 			unsigned char *buf = NULL;
1506 
1507 			if (sgl)
1508 				buf = kmap(sg_page(sgl)) + sgl->offset;
1509 
1510 			if (buf) {
1511 				memset(buf, 0, sgl->length);
1512 				kunmap(sg_page(sgl));
1513 			}
1514 		}
1515 
1516 		rc = transport_generic_map_mem_to_cmd(se_cmd, sgl, sgl_count,
1517 				sgl_bidi, sgl_bidi_count);
1518 		if (rc != 0) {
1519 			transport_generic_request_failure(se_cmd, rc);
1520 			return 0;
1521 		}
1522 	}
1523 
1524 	/*
1525 	 * Check if we need to delay processing because of ALUA
1526 	 * Active/NonOptimized primary access state..
1527 	 */
1528 	core_alua_check_nonop_delay(se_cmd);
1529 
1530 	transport_handle_cdb_direct(se_cmd);
1531 	return 0;
1532 }
1533 EXPORT_SYMBOL(target_submit_cmd_map_sgls);
1534 
1535 /*
1536  * target_submit_cmd - lookup unpacked lun and submit uninitialized se_cmd
1537  *
1538  * @se_cmd: command descriptor to submit
1539  * @se_sess: associated se_sess for endpoint
1540  * @cdb: pointer to SCSI CDB
1541  * @sense: pointer to SCSI sense buffer
1542  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1543  * @data_length: fabric expected data transfer length
1544  * @task_addr: SAM task attribute
1545  * @data_dir: DMA data direction
1546  * @flags: flags for command submission from target_sc_flags_tables
1547  *
1548  * Task tags are supported if the caller has set @se_cmd->tag.
1549  *
1550  * Returns non zero to signal active I/O shutdown failure.  All other
1551  * setup exceptions will be returned as a SCSI CHECK_CONDITION response,
1552  * but still return zero here.
1553  *
1554  * This may only be called from process context, and also currently
1555  * assumes internal allocation of fabric payload buffer by target-core.
1556  *
1557  * It also assumes interal target core SGL memory allocation.
1558  */
1559 int target_submit_cmd(struct se_cmd *se_cmd, struct se_session *se_sess,
1560 		unsigned char *cdb, unsigned char *sense, u64 unpacked_lun,
1561 		u32 data_length, int task_attr, int data_dir, int flags)
1562 {
1563 	return target_submit_cmd_map_sgls(se_cmd, se_sess, cdb, sense,
1564 			unpacked_lun, data_length, task_attr, data_dir,
1565 			flags, NULL, 0, NULL, 0, NULL, 0);
1566 }
1567 EXPORT_SYMBOL(target_submit_cmd);
1568 
1569 static void target_complete_tmr_failure(struct work_struct *work)
1570 {
1571 	struct se_cmd *se_cmd = container_of(work, struct se_cmd, work);
1572 
1573 	se_cmd->se_tmr_req->response = TMR_LUN_DOES_NOT_EXIST;
1574 	se_cmd->se_tfo->queue_tm_rsp(se_cmd);
1575 
1576 	transport_cmd_check_stop_to_fabric(se_cmd);
1577 }
1578 
1579 /**
1580  * target_submit_tmr - lookup unpacked lun and submit uninitialized se_cmd
1581  *                     for TMR CDBs
1582  *
1583  * @se_cmd: command descriptor to submit
1584  * @se_sess: associated se_sess for endpoint
1585  * @sense: pointer to SCSI sense buffer
1586  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1587  * @fabric_context: fabric context for TMR req
1588  * @tm_type: Type of TM request
1589  * @gfp: gfp type for caller
1590  * @tag: referenced task tag for TMR_ABORT_TASK
1591  * @flags: submit cmd flags
1592  *
1593  * Callable from all contexts.
1594  **/
1595 
1596 int target_submit_tmr(struct se_cmd *se_cmd, struct se_session *se_sess,
1597 		unsigned char *sense, u64 unpacked_lun,
1598 		void *fabric_tmr_ptr, unsigned char tm_type,
1599 		gfp_t gfp, u64 tag, int flags)
1600 {
1601 	struct se_portal_group *se_tpg;
1602 	int ret;
1603 
1604 	se_tpg = se_sess->se_tpg;
1605 	BUG_ON(!se_tpg);
1606 
1607 	transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess,
1608 			      0, DMA_NONE, TCM_SIMPLE_TAG, sense);
1609 	/*
1610 	 * FIXME: Currently expect caller to handle se_cmd->se_tmr_req
1611 	 * allocation failure.
1612 	 */
1613 	ret = core_tmr_alloc_req(se_cmd, fabric_tmr_ptr, tm_type, gfp);
1614 	if (ret < 0)
1615 		return -ENOMEM;
1616 
1617 	if (tm_type == TMR_ABORT_TASK)
1618 		se_cmd->se_tmr_req->ref_task_tag = tag;
1619 
1620 	/* See target_submit_cmd for commentary */
1621 	ret = target_get_sess_cmd(se_cmd, flags & TARGET_SCF_ACK_KREF);
1622 	if (ret) {
1623 		core_tmr_release_req(se_cmd->se_tmr_req);
1624 		return ret;
1625 	}
1626 
1627 	ret = transport_lookup_tmr_lun(se_cmd, unpacked_lun);
1628 	if (ret) {
1629 		/*
1630 		 * For callback during failure handling, push this work off
1631 		 * to process context with TMR_LUN_DOES_NOT_EXIST status.
1632 		 */
1633 		INIT_WORK(&se_cmd->work, target_complete_tmr_failure);
1634 		schedule_work(&se_cmd->work);
1635 		return 0;
1636 	}
1637 	transport_generic_handle_tmr(se_cmd);
1638 	return 0;
1639 }
1640 EXPORT_SYMBOL(target_submit_tmr);
1641 
1642 /*
1643  * Handle SAM-esque emulation for generic transport request failures.
1644  */
1645 void transport_generic_request_failure(struct se_cmd *cmd,
1646 		sense_reason_t sense_reason)
1647 {
1648 	int ret = 0, post_ret = 0;
1649 
1650 	if (transport_check_aborted_status(cmd, 1))
1651 		return;
1652 
1653 	pr_debug("-----[ Storage Engine Exception for cmd: %p ITT: 0x%08llx"
1654 		" CDB: 0x%02x\n", cmd, cmd->tag, cmd->t_task_cdb[0]);
1655 	pr_debug("-----[ i_state: %d t_state: %d sense_reason: %d\n",
1656 		cmd->se_tfo->get_cmd_state(cmd),
1657 		cmd->t_state, sense_reason);
1658 	pr_debug("-----[ CMD_T_ACTIVE: %d CMD_T_STOP: %d CMD_T_SENT: %d\n",
1659 		(cmd->transport_state & CMD_T_ACTIVE) != 0,
1660 		(cmd->transport_state & CMD_T_STOP) != 0,
1661 		(cmd->transport_state & CMD_T_SENT) != 0);
1662 
1663 	/*
1664 	 * For SAM Task Attribute emulation for failed struct se_cmd
1665 	 */
1666 	transport_complete_task_attr(cmd);
1667 	/*
1668 	 * Handle special case for COMPARE_AND_WRITE failure, where the
1669 	 * callback is expected to drop the per device ->caw_sem.
1670 	 */
1671 	if ((cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) &&
1672 	     cmd->transport_complete_callback)
1673 		cmd->transport_complete_callback(cmd, false, &post_ret);
1674 
1675 	switch (sense_reason) {
1676 	case TCM_NON_EXISTENT_LUN:
1677 	case TCM_UNSUPPORTED_SCSI_OPCODE:
1678 	case TCM_INVALID_CDB_FIELD:
1679 	case TCM_INVALID_PARAMETER_LIST:
1680 	case TCM_PARAMETER_LIST_LENGTH_ERROR:
1681 	case TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE:
1682 	case TCM_UNKNOWN_MODE_PAGE:
1683 	case TCM_WRITE_PROTECTED:
1684 	case TCM_ADDRESS_OUT_OF_RANGE:
1685 	case TCM_CHECK_CONDITION_ABORT_CMD:
1686 	case TCM_CHECK_CONDITION_UNIT_ATTENTION:
1687 	case TCM_CHECK_CONDITION_NOT_READY:
1688 	case TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED:
1689 	case TCM_LOGICAL_BLOCK_APP_TAG_CHECK_FAILED:
1690 	case TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED:
1691 	case TCM_COPY_TARGET_DEVICE_NOT_REACHABLE:
1692 	case TCM_TOO_MANY_TARGET_DESCS:
1693 	case TCM_UNSUPPORTED_TARGET_DESC_TYPE_CODE:
1694 	case TCM_TOO_MANY_SEGMENT_DESCS:
1695 	case TCM_UNSUPPORTED_SEGMENT_DESC_TYPE_CODE:
1696 		break;
1697 	case TCM_OUT_OF_RESOURCES:
1698 		sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
1699 		break;
1700 	case TCM_RESERVATION_CONFLICT:
1701 		/*
1702 		 * No SENSE Data payload for this case, set SCSI Status
1703 		 * and queue the response to $FABRIC_MOD.
1704 		 *
1705 		 * Uses linux/include/scsi/scsi.h SAM status codes defs
1706 		 */
1707 		cmd->scsi_status = SAM_STAT_RESERVATION_CONFLICT;
1708 		/*
1709 		 * For UA Interlock Code 11b, a RESERVATION CONFLICT will
1710 		 * establish a UNIT ATTENTION with PREVIOUS RESERVATION
1711 		 * CONFLICT STATUS.
1712 		 *
1713 		 * See spc4r17, section 7.4.6 Control Mode Page, Table 349
1714 		 */
1715 		if (cmd->se_sess &&
1716 		    cmd->se_dev->dev_attrib.emulate_ua_intlck_ctrl == 2) {
1717 			target_ua_allocate_lun(cmd->se_sess->se_node_acl,
1718 					       cmd->orig_fe_lun, 0x2C,
1719 					ASCQ_2CH_PREVIOUS_RESERVATION_CONFLICT_STATUS);
1720 		}
1721 		trace_target_cmd_complete(cmd);
1722 		ret = cmd->se_tfo->queue_status(cmd);
1723 		if (ret == -EAGAIN || ret == -ENOMEM)
1724 			goto queue_full;
1725 		goto check_stop;
1726 	default:
1727 		pr_err("Unknown transport error for CDB 0x%02x: %d\n",
1728 			cmd->t_task_cdb[0], sense_reason);
1729 		sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
1730 		break;
1731 	}
1732 
1733 	ret = transport_send_check_condition_and_sense(cmd, sense_reason, 0);
1734 	if (ret == -EAGAIN || ret == -ENOMEM)
1735 		goto queue_full;
1736 
1737 check_stop:
1738 	transport_lun_remove_cmd(cmd);
1739 	transport_cmd_check_stop_to_fabric(cmd);
1740 	return;
1741 
1742 queue_full:
1743 	cmd->t_state = TRANSPORT_COMPLETE_QF_OK;
1744 	transport_handle_queue_full(cmd, cmd->se_dev);
1745 }
1746 EXPORT_SYMBOL(transport_generic_request_failure);
1747 
1748 void __target_execute_cmd(struct se_cmd *cmd, bool do_checks)
1749 {
1750 	sense_reason_t ret;
1751 
1752 	if (!cmd->execute_cmd) {
1753 		ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
1754 		goto err;
1755 	}
1756 	if (do_checks) {
1757 		/*
1758 		 * Check for an existing UNIT ATTENTION condition after
1759 		 * target_handle_task_attr() has done SAM task attr
1760 		 * checking, and possibly have already defered execution
1761 		 * out to target_restart_delayed_cmds() context.
1762 		 */
1763 		ret = target_scsi3_ua_check(cmd);
1764 		if (ret)
1765 			goto err;
1766 
1767 		ret = target_alua_state_check(cmd);
1768 		if (ret)
1769 			goto err;
1770 
1771 		ret = target_check_reservation(cmd);
1772 		if (ret) {
1773 			cmd->scsi_status = SAM_STAT_RESERVATION_CONFLICT;
1774 			goto err;
1775 		}
1776 	}
1777 
1778 	ret = cmd->execute_cmd(cmd);
1779 	if (!ret)
1780 		return;
1781 err:
1782 	spin_lock_irq(&cmd->t_state_lock);
1783 	cmd->transport_state &= ~CMD_T_SENT;
1784 	spin_unlock_irq(&cmd->t_state_lock);
1785 
1786 	transport_generic_request_failure(cmd, ret);
1787 }
1788 
1789 static int target_write_prot_action(struct se_cmd *cmd)
1790 {
1791 	u32 sectors;
1792 	/*
1793 	 * Perform WRITE_INSERT of PI using software emulation when backend
1794 	 * device has PI enabled, if the transport has not already generated
1795 	 * PI using hardware WRITE_INSERT offload.
1796 	 */
1797 	switch (cmd->prot_op) {
1798 	case TARGET_PROT_DOUT_INSERT:
1799 		if (!(cmd->se_sess->sup_prot_ops & TARGET_PROT_DOUT_INSERT))
1800 			sbc_dif_generate(cmd);
1801 		break;
1802 	case TARGET_PROT_DOUT_STRIP:
1803 		if (cmd->se_sess->sup_prot_ops & TARGET_PROT_DOUT_STRIP)
1804 			break;
1805 
1806 		sectors = cmd->data_length >> ilog2(cmd->se_dev->dev_attrib.block_size);
1807 		cmd->pi_err = sbc_dif_verify(cmd, cmd->t_task_lba,
1808 					     sectors, 0, cmd->t_prot_sg, 0);
1809 		if (unlikely(cmd->pi_err)) {
1810 			spin_lock_irq(&cmd->t_state_lock);
1811 			cmd->transport_state &= ~CMD_T_SENT;
1812 			spin_unlock_irq(&cmd->t_state_lock);
1813 			transport_generic_request_failure(cmd, cmd->pi_err);
1814 			return -1;
1815 		}
1816 		break;
1817 	default:
1818 		break;
1819 	}
1820 
1821 	return 0;
1822 }
1823 
1824 static bool target_handle_task_attr(struct se_cmd *cmd)
1825 {
1826 	struct se_device *dev = cmd->se_dev;
1827 
1828 	if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
1829 		return false;
1830 
1831 	cmd->se_cmd_flags |= SCF_TASK_ATTR_SET;
1832 
1833 	/*
1834 	 * Check for the existence of HEAD_OF_QUEUE, and if true return 1
1835 	 * to allow the passed struct se_cmd list of tasks to the front of the list.
1836 	 */
1837 	switch (cmd->sam_task_attr) {
1838 	case TCM_HEAD_TAG:
1839 		pr_debug("Added HEAD_OF_QUEUE for CDB: 0x%02x\n",
1840 			 cmd->t_task_cdb[0]);
1841 		return false;
1842 	case TCM_ORDERED_TAG:
1843 		atomic_inc_mb(&dev->dev_ordered_sync);
1844 
1845 		pr_debug("Added ORDERED for CDB: 0x%02x to ordered list\n",
1846 			 cmd->t_task_cdb[0]);
1847 
1848 		/*
1849 		 * Execute an ORDERED command if no other older commands
1850 		 * exist that need to be completed first.
1851 		 */
1852 		if (!atomic_read(&dev->simple_cmds))
1853 			return false;
1854 		break;
1855 	default:
1856 		/*
1857 		 * For SIMPLE and UNTAGGED Task Attribute commands
1858 		 */
1859 		atomic_inc_mb(&dev->simple_cmds);
1860 		break;
1861 	}
1862 
1863 	if (atomic_read(&dev->dev_ordered_sync) == 0)
1864 		return false;
1865 
1866 	spin_lock(&dev->delayed_cmd_lock);
1867 	list_add_tail(&cmd->se_delayed_node, &dev->delayed_cmd_list);
1868 	spin_unlock(&dev->delayed_cmd_lock);
1869 
1870 	pr_debug("Added CDB: 0x%02x Task Attr: 0x%02x to delayed CMD listn",
1871 		cmd->t_task_cdb[0], cmd->sam_task_attr);
1872 	return true;
1873 }
1874 
1875 static int __transport_check_aborted_status(struct se_cmd *, int);
1876 
1877 void target_execute_cmd(struct se_cmd *cmd)
1878 {
1879 	/*
1880 	 * Determine if frontend context caller is requesting the stopping of
1881 	 * this command for frontend exceptions.
1882 	 *
1883 	 * If the received CDB has aleady been aborted stop processing it here.
1884 	 */
1885 	spin_lock_irq(&cmd->t_state_lock);
1886 	if (__transport_check_aborted_status(cmd, 1)) {
1887 		spin_unlock_irq(&cmd->t_state_lock);
1888 		return;
1889 	}
1890 	if (cmd->transport_state & CMD_T_STOP) {
1891 		pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08llx\n",
1892 			__func__, __LINE__, cmd->tag);
1893 
1894 		spin_unlock_irq(&cmd->t_state_lock);
1895 		complete_all(&cmd->t_transport_stop_comp);
1896 		return;
1897 	}
1898 
1899 	cmd->t_state = TRANSPORT_PROCESSING;
1900 	cmd->transport_state |= CMD_T_ACTIVE | CMD_T_SENT;
1901 	spin_unlock_irq(&cmd->t_state_lock);
1902 
1903 	if (target_write_prot_action(cmd))
1904 		return;
1905 
1906 	if (target_handle_task_attr(cmd)) {
1907 		spin_lock_irq(&cmd->t_state_lock);
1908 		cmd->transport_state &= ~CMD_T_SENT;
1909 		spin_unlock_irq(&cmd->t_state_lock);
1910 		return;
1911 	}
1912 
1913 	__target_execute_cmd(cmd, true);
1914 }
1915 EXPORT_SYMBOL(target_execute_cmd);
1916 
1917 /*
1918  * Process all commands up to the last received ORDERED task attribute which
1919  * requires another blocking boundary
1920  */
1921 static void target_restart_delayed_cmds(struct se_device *dev)
1922 {
1923 	for (;;) {
1924 		struct se_cmd *cmd;
1925 
1926 		spin_lock(&dev->delayed_cmd_lock);
1927 		if (list_empty(&dev->delayed_cmd_list)) {
1928 			spin_unlock(&dev->delayed_cmd_lock);
1929 			break;
1930 		}
1931 
1932 		cmd = list_entry(dev->delayed_cmd_list.next,
1933 				 struct se_cmd, se_delayed_node);
1934 		list_del(&cmd->se_delayed_node);
1935 		spin_unlock(&dev->delayed_cmd_lock);
1936 
1937 		__target_execute_cmd(cmd, true);
1938 
1939 		if (cmd->sam_task_attr == TCM_ORDERED_TAG)
1940 			break;
1941 	}
1942 }
1943 
1944 /*
1945  * Called from I/O completion to determine which dormant/delayed
1946  * and ordered cmds need to have their tasks added to the execution queue.
1947  */
1948 static void transport_complete_task_attr(struct se_cmd *cmd)
1949 {
1950 	struct se_device *dev = cmd->se_dev;
1951 
1952 	if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
1953 		return;
1954 
1955 	if (!(cmd->se_cmd_flags & SCF_TASK_ATTR_SET))
1956 		goto restart;
1957 
1958 	if (cmd->sam_task_attr == TCM_SIMPLE_TAG) {
1959 		atomic_dec_mb(&dev->simple_cmds);
1960 		dev->dev_cur_ordered_id++;
1961 	} else if (cmd->sam_task_attr == TCM_HEAD_TAG) {
1962 		dev->dev_cur_ordered_id++;
1963 		pr_debug("Incremented dev_cur_ordered_id: %u for HEAD_OF_QUEUE\n",
1964 			 dev->dev_cur_ordered_id);
1965 	} else if (cmd->sam_task_attr == TCM_ORDERED_TAG) {
1966 		atomic_dec_mb(&dev->dev_ordered_sync);
1967 
1968 		dev->dev_cur_ordered_id++;
1969 		pr_debug("Incremented dev_cur_ordered_id: %u for ORDERED\n",
1970 			 dev->dev_cur_ordered_id);
1971 	}
1972 restart:
1973 	target_restart_delayed_cmds(dev);
1974 }
1975 
1976 static void transport_complete_qf(struct se_cmd *cmd)
1977 {
1978 	int ret = 0;
1979 
1980 	transport_complete_task_attr(cmd);
1981 
1982 	if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) {
1983 		trace_target_cmd_complete(cmd);
1984 		ret = cmd->se_tfo->queue_status(cmd);
1985 		goto out;
1986 	}
1987 
1988 	switch (cmd->data_direction) {
1989 	case DMA_FROM_DEVICE:
1990 		if (cmd->scsi_status)
1991 			goto queue_status;
1992 
1993 		trace_target_cmd_complete(cmd);
1994 		ret = cmd->se_tfo->queue_data_in(cmd);
1995 		break;
1996 	case DMA_TO_DEVICE:
1997 		if (cmd->se_cmd_flags & SCF_BIDI) {
1998 			ret = cmd->se_tfo->queue_data_in(cmd);
1999 			break;
2000 		}
2001 		/* Fall through for DMA_TO_DEVICE */
2002 	case DMA_NONE:
2003 queue_status:
2004 		trace_target_cmd_complete(cmd);
2005 		ret = cmd->se_tfo->queue_status(cmd);
2006 		break;
2007 	default:
2008 		break;
2009 	}
2010 
2011 out:
2012 	if (ret < 0) {
2013 		transport_handle_queue_full(cmd, cmd->se_dev);
2014 		return;
2015 	}
2016 	transport_lun_remove_cmd(cmd);
2017 	transport_cmd_check_stop_to_fabric(cmd);
2018 }
2019 
2020 static void transport_handle_queue_full(
2021 	struct se_cmd *cmd,
2022 	struct se_device *dev)
2023 {
2024 	spin_lock_irq(&dev->qf_cmd_lock);
2025 	list_add_tail(&cmd->se_qf_node, &cmd->se_dev->qf_cmd_list);
2026 	atomic_inc_mb(&dev->dev_qf_count);
2027 	spin_unlock_irq(&cmd->se_dev->qf_cmd_lock);
2028 
2029 	schedule_work(&cmd->se_dev->qf_work_queue);
2030 }
2031 
2032 static bool target_read_prot_action(struct se_cmd *cmd)
2033 {
2034 	switch (cmd->prot_op) {
2035 	case TARGET_PROT_DIN_STRIP:
2036 		if (!(cmd->se_sess->sup_prot_ops & TARGET_PROT_DIN_STRIP)) {
2037 			u32 sectors = cmd->data_length >>
2038 				  ilog2(cmd->se_dev->dev_attrib.block_size);
2039 
2040 			cmd->pi_err = sbc_dif_verify(cmd, cmd->t_task_lba,
2041 						     sectors, 0, cmd->t_prot_sg,
2042 						     0);
2043 			if (cmd->pi_err)
2044 				return true;
2045 		}
2046 		break;
2047 	case TARGET_PROT_DIN_INSERT:
2048 		if (cmd->se_sess->sup_prot_ops & TARGET_PROT_DIN_INSERT)
2049 			break;
2050 
2051 		sbc_dif_generate(cmd);
2052 		break;
2053 	default:
2054 		break;
2055 	}
2056 
2057 	return false;
2058 }
2059 
2060 static void target_complete_ok_work(struct work_struct *work)
2061 {
2062 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
2063 	int ret;
2064 
2065 	/*
2066 	 * Check if we need to move delayed/dormant tasks from cmds on the
2067 	 * delayed execution list after a HEAD_OF_QUEUE or ORDERED Task
2068 	 * Attribute.
2069 	 */
2070 	transport_complete_task_attr(cmd);
2071 
2072 	/*
2073 	 * Check to schedule QUEUE_FULL work, or execute an existing
2074 	 * cmd->transport_qf_callback()
2075 	 */
2076 	if (atomic_read(&cmd->se_dev->dev_qf_count) != 0)
2077 		schedule_work(&cmd->se_dev->qf_work_queue);
2078 
2079 	/*
2080 	 * Check if we need to send a sense buffer from
2081 	 * the struct se_cmd in question.
2082 	 */
2083 	if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) {
2084 		WARN_ON(!cmd->scsi_status);
2085 		ret = transport_send_check_condition_and_sense(
2086 					cmd, 0, 1);
2087 		if (ret == -EAGAIN || ret == -ENOMEM)
2088 			goto queue_full;
2089 
2090 		transport_lun_remove_cmd(cmd);
2091 		transport_cmd_check_stop_to_fabric(cmd);
2092 		return;
2093 	}
2094 	/*
2095 	 * Check for a callback, used by amongst other things
2096 	 * XDWRITE_READ_10 and COMPARE_AND_WRITE emulation.
2097 	 */
2098 	if (cmd->transport_complete_callback) {
2099 		sense_reason_t rc;
2100 		bool caw = (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE);
2101 		bool zero_dl = !(cmd->data_length);
2102 		int post_ret = 0;
2103 
2104 		rc = cmd->transport_complete_callback(cmd, true, &post_ret);
2105 		if (!rc && !post_ret) {
2106 			if (caw && zero_dl)
2107 				goto queue_rsp;
2108 
2109 			return;
2110 		} else if (rc) {
2111 			ret = transport_send_check_condition_and_sense(cmd,
2112 						rc, 0);
2113 			if (ret == -EAGAIN || ret == -ENOMEM)
2114 				goto queue_full;
2115 
2116 			transport_lun_remove_cmd(cmd);
2117 			transport_cmd_check_stop_to_fabric(cmd);
2118 			return;
2119 		}
2120 	}
2121 
2122 queue_rsp:
2123 	switch (cmd->data_direction) {
2124 	case DMA_FROM_DEVICE:
2125 		if (cmd->scsi_status)
2126 			goto queue_status;
2127 
2128 		atomic_long_add(cmd->data_length,
2129 				&cmd->se_lun->lun_stats.tx_data_octets);
2130 		/*
2131 		 * Perform READ_STRIP of PI using software emulation when
2132 		 * backend had PI enabled, if the transport will not be
2133 		 * performing hardware READ_STRIP offload.
2134 		 */
2135 		if (target_read_prot_action(cmd)) {
2136 			ret = transport_send_check_condition_and_sense(cmd,
2137 						cmd->pi_err, 0);
2138 			if (ret == -EAGAIN || ret == -ENOMEM)
2139 				goto queue_full;
2140 
2141 			transport_lun_remove_cmd(cmd);
2142 			transport_cmd_check_stop_to_fabric(cmd);
2143 			return;
2144 		}
2145 
2146 		trace_target_cmd_complete(cmd);
2147 		ret = cmd->se_tfo->queue_data_in(cmd);
2148 		if (ret == -EAGAIN || ret == -ENOMEM)
2149 			goto queue_full;
2150 		break;
2151 	case DMA_TO_DEVICE:
2152 		atomic_long_add(cmd->data_length,
2153 				&cmd->se_lun->lun_stats.rx_data_octets);
2154 		/*
2155 		 * Check if we need to send READ payload for BIDI-COMMAND
2156 		 */
2157 		if (cmd->se_cmd_flags & SCF_BIDI) {
2158 			atomic_long_add(cmd->data_length,
2159 					&cmd->se_lun->lun_stats.tx_data_octets);
2160 			ret = cmd->se_tfo->queue_data_in(cmd);
2161 			if (ret == -EAGAIN || ret == -ENOMEM)
2162 				goto queue_full;
2163 			break;
2164 		}
2165 		/* Fall through for DMA_TO_DEVICE */
2166 	case DMA_NONE:
2167 queue_status:
2168 		trace_target_cmd_complete(cmd);
2169 		ret = cmd->se_tfo->queue_status(cmd);
2170 		if (ret == -EAGAIN || ret == -ENOMEM)
2171 			goto queue_full;
2172 		break;
2173 	default:
2174 		break;
2175 	}
2176 
2177 	transport_lun_remove_cmd(cmd);
2178 	transport_cmd_check_stop_to_fabric(cmd);
2179 	return;
2180 
2181 queue_full:
2182 	pr_debug("Handling complete_ok QUEUE_FULL: se_cmd: %p,"
2183 		" data_direction: %d\n", cmd, cmd->data_direction);
2184 	cmd->t_state = TRANSPORT_COMPLETE_QF_OK;
2185 	transport_handle_queue_full(cmd, cmd->se_dev);
2186 }
2187 
2188 void target_free_sgl(struct scatterlist *sgl, int nents)
2189 {
2190 	struct scatterlist *sg;
2191 	int count;
2192 
2193 	for_each_sg(sgl, sg, nents, count)
2194 		__free_page(sg_page(sg));
2195 
2196 	kfree(sgl);
2197 }
2198 EXPORT_SYMBOL(target_free_sgl);
2199 
2200 static inline void transport_reset_sgl_orig(struct se_cmd *cmd)
2201 {
2202 	/*
2203 	 * Check for saved t_data_sg that may be used for COMPARE_AND_WRITE
2204 	 * emulation, and free + reset pointers if necessary..
2205 	 */
2206 	if (!cmd->t_data_sg_orig)
2207 		return;
2208 
2209 	kfree(cmd->t_data_sg);
2210 	cmd->t_data_sg = cmd->t_data_sg_orig;
2211 	cmd->t_data_sg_orig = NULL;
2212 	cmd->t_data_nents = cmd->t_data_nents_orig;
2213 	cmd->t_data_nents_orig = 0;
2214 }
2215 
2216 static inline void transport_free_pages(struct se_cmd *cmd)
2217 {
2218 	if (!(cmd->se_cmd_flags & SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC)) {
2219 		target_free_sgl(cmd->t_prot_sg, cmd->t_prot_nents);
2220 		cmd->t_prot_sg = NULL;
2221 		cmd->t_prot_nents = 0;
2222 	}
2223 
2224 	if (cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) {
2225 		/*
2226 		 * Release special case READ buffer payload required for
2227 		 * SG_TO_MEM_NOALLOC to function with COMPARE_AND_WRITE
2228 		 */
2229 		if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) {
2230 			target_free_sgl(cmd->t_bidi_data_sg,
2231 					   cmd->t_bidi_data_nents);
2232 			cmd->t_bidi_data_sg = NULL;
2233 			cmd->t_bidi_data_nents = 0;
2234 		}
2235 		transport_reset_sgl_orig(cmd);
2236 		return;
2237 	}
2238 	transport_reset_sgl_orig(cmd);
2239 
2240 	target_free_sgl(cmd->t_data_sg, cmd->t_data_nents);
2241 	cmd->t_data_sg = NULL;
2242 	cmd->t_data_nents = 0;
2243 
2244 	target_free_sgl(cmd->t_bidi_data_sg, cmd->t_bidi_data_nents);
2245 	cmd->t_bidi_data_sg = NULL;
2246 	cmd->t_bidi_data_nents = 0;
2247 }
2248 
2249 /**
2250  * transport_put_cmd - release a reference to a command
2251  * @cmd:       command to release
2252  *
2253  * This routine releases our reference to the command and frees it if possible.
2254  */
2255 static int transport_put_cmd(struct se_cmd *cmd)
2256 {
2257 	BUG_ON(!cmd->se_tfo);
2258 	/*
2259 	 * If this cmd has been setup with target_get_sess_cmd(), drop
2260 	 * the kref and call ->release_cmd() in kref callback.
2261 	 */
2262 	return target_put_sess_cmd(cmd);
2263 }
2264 
2265 void *transport_kmap_data_sg(struct se_cmd *cmd)
2266 {
2267 	struct scatterlist *sg = cmd->t_data_sg;
2268 	struct page **pages;
2269 	int i;
2270 
2271 	/*
2272 	 * We need to take into account a possible offset here for fabrics like
2273 	 * tcm_loop who may be using a contig buffer from the SCSI midlayer for
2274 	 * control CDBs passed as SGLs via transport_generic_map_mem_to_cmd()
2275 	 */
2276 	if (!cmd->t_data_nents)
2277 		return NULL;
2278 
2279 	BUG_ON(!sg);
2280 	if (cmd->t_data_nents == 1)
2281 		return kmap(sg_page(sg)) + sg->offset;
2282 
2283 	/* >1 page. use vmap */
2284 	pages = kmalloc(sizeof(*pages) * cmd->t_data_nents, GFP_KERNEL);
2285 	if (!pages)
2286 		return NULL;
2287 
2288 	/* convert sg[] to pages[] */
2289 	for_each_sg(cmd->t_data_sg, sg, cmd->t_data_nents, i) {
2290 		pages[i] = sg_page(sg);
2291 	}
2292 
2293 	cmd->t_data_vmap = vmap(pages, cmd->t_data_nents,  VM_MAP, PAGE_KERNEL);
2294 	kfree(pages);
2295 	if (!cmd->t_data_vmap)
2296 		return NULL;
2297 
2298 	return cmd->t_data_vmap + cmd->t_data_sg[0].offset;
2299 }
2300 EXPORT_SYMBOL(transport_kmap_data_sg);
2301 
2302 void transport_kunmap_data_sg(struct se_cmd *cmd)
2303 {
2304 	if (!cmd->t_data_nents) {
2305 		return;
2306 	} else if (cmd->t_data_nents == 1) {
2307 		kunmap(sg_page(cmd->t_data_sg));
2308 		return;
2309 	}
2310 
2311 	vunmap(cmd->t_data_vmap);
2312 	cmd->t_data_vmap = NULL;
2313 }
2314 EXPORT_SYMBOL(transport_kunmap_data_sg);
2315 
2316 int
2317 target_alloc_sgl(struct scatterlist **sgl, unsigned int *nents, u32 length,
2318 		 bool zero_page, bool chainable)
2319 {
2320 	struct scatterlist *sg;
2321 	struct page *page;
2322 	gfp_t zero_flag = (zero_page) ? __GFP_ZERO : 0;
2323 	unsigned int nalloc, nent;
2324 	int i = 0;
2325 
2326 	nalloc = nent = DIV_ROUND_UP(length, PAGE_SIZE);
2327 	if (chainable)
2328 		nalloc++;
2329 	sg = kmalloc_array(nalloc, sizeof(struct scatterlist), GFP_KERNEL);
2330 	if (!sg)
2331 		return -ENOMEM;
2332 
2333 	sg_init_table(sg, nalloc);
2334 
2335 	while (length) {
2336 		u32 page_len = min_t(u32, length, PAGE_SIZE);
2337 		page = alloc_page(GFP_KERNEL | zero_flag);
2338 		if (!page)
2339 			goto out;
2340 
2341 		sg_set_page(&sg[i], page, page_len, 0);
2342 		length -= page_len;
2343 		i++;
2344 	}
2345 	*sgl = sg;
2346 	*nents = nent;
2347 	return 0;
2348 
2349 out:
2350 	while (i > 0) {
2351 		i--;
2352 		__free_page(sg_page(&sg[i]));
2353 	}
2354 	kfree(sg);
2355 	return -ENOMEM;
2356 }
2357 EXPORT_SYMBOL(target_alloc_sgl);
2358 
2359 /*
2360  * Allocate any required resources to execute the command.  For writes we
2361  * might not have the payload yet, so notify the fabric via a call to
2362  * ->write_pending instead. Otherwise place it on the execution queue.
2363  */
2364 sense_reason_t
2365 transport_generic_new_cmd(struct se_cmd *cmd)
2366 {
2367 	unsigned long flags;
2368 	int ret = 0;
2369 	bool zero_flag = !(cmd->se_cmd_flags & SCF_SCSI_DATA_CDB);
2370 
2371 	if (cmd->prot_op != TARGET_PROT_NORMAL &&
2372 	    !(cmd->se_cmd_flags & SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC)) {
2373 		ret = target_alloc_sgl(&cmd->t_prot_sg, &cmd->t_prot_nents,
2374 				       cmd->prot_length, true, false);
2375 		if (ret < 0)
2376 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2377 	}
2378 
2379 	/*
2380 	 * Determine is the TCM fabric module has already allocated physical
2381 	 * memory, and is directly calling transport_generic_map_mem_to_cmd()
2382 	 * beforehand.
2383 	 */
2384 	if (!(cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) &&
2385 	    cmd->data_length) {
2386 
2387 		if ((cmd->se_cmd_flags & SCF_BIDI) ||
2388 		    (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE)) {
2389 			u32 bidi_length;
2390 
2391 			if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE)
2392 				bidi_length = cmd->t_task_nolb *
2393 					      cmd->se_dev->dev_attrib.block_size;
2394 			else
2395 				bidi_length = cmd->data_length;
2396 
2397 			ret = target_alloc_sgl(&cmd->t_bidi_data_sg,
2398 					       &cmd->t_bidi_data_nents,
2399 					       bidi_length, zero_flag, false);
2400 			if (ret < 0)
2401 				return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2402 		}
2403 
2404 		ret = target_alloc_sgl(&cmd->t_data_sg, &cmd->t_data_nents,
2405 				       cmd->data_length, zero_flag, false);
2406 		if (ret < 0)
2407 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2408 	} else if ((cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) &&
2409 		    cmd->data_length) {
2410 		/*
2411 		 * Special case for COMPARE_AND_WRITE with fabrics
2412 		 * using SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC.
2413 		 */
2414 		u32 caw_length = cmd->t_task_nolb *
2415 				 cmd->se_dev->dev_attrib.block_size;
2416 
2417 		ret = target_alloc_sgl(&cmd->t_bidi_data_sg,
2418 				       &cmd->t_bidi_data_nents,
2419 				       caw_length, zero_flag, false);
2420 		if (ret < 0)
2421 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2422 	}
2423 	/*
2424 	 * If this command is not a write we can execute it right here,
2425 	 * for write buffers we need to notify the fabric driver first
2426 	 * and let it call back once the write buffers are ready.
2427 	 */
2428 	target_add_to_state_list(cmd);
2429 	if (cmd->data_direction != DMA_TO_DEVICE || cmd->data_length == 0) {
2430 		target_execute_cmd(cmd);
2431 		return 0;
2432 	}
2433 
2434 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2435 	cmd->t_state = TRANSPORT_WRITE_PENDING;
2436 	/*
2437 	 * Determine if frontend context caller is requesting the stopping of
2438 	 * this command for frontend exceptions.
2439 	 */
2440 	if (cmd->transport_state & CMD_T_STOP) {
2441 		pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08llx\n",
2442 			 __func__, __LINE__, cmd->tag);
2443 
2444 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2445 
2446 		complete_all(&cmd->t_transport_stop_comp);
2447 		return 0;
2448 	}
2449 	cmd->transport_state &= ~CMD_T_ACTIVE;
2450 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2451 
2452 	ret = cmd->se_tfo->write_pending(cmd);
2453 	if (ret == -EAGAIN || ret == -ENOMEM)
2454 		goto queue_full;
2455 
2456 	/* fabric drivers should only return -EAGAIN or -ENOMEM as error */
2457 	WARN_ON(ret);
2458 
2459 	return (!ret) ? 0 : TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2460 
2461 queue_full:
2462 	pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n", cmd);
2463 	cmd->t_state = TRANSPORT_COMPLETE_QF_WP;
2464 	transport_handle_queue_full(cmd, cmd->se_dev);
2465 	return 0;
2466 }
2467 EXPORT_SYMBOL(transport_generic_new_cmd);
2468 
2469 static void transport_write_pending_qf(struct se_cmd *cmd)
2470 {
2471 	int ret;
2472 
2473 	ret = cmd->se_tfo->write_pending(cmd);
2474 	if (ret == -EAGAIN || ret == -ENOMEM) {
2475 		pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n",
2476 			 cmd);
2477 		transport_handle_queue_full(cmd, cmd->se_dev);
2478 	}
2479 }
2480 
2481 static bool
2482 __transport_wait_for_tasks(struct se_cmd *, bool, bool *, bool *,
2483 			   unsigned long *flags);
2484 
2485 static void target_wait_free_cmd(struct se_cmd *cmd, bool *aborted, bool *tas)
2486 {
2487 	unsigned long flags;
2488 
2489 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2490 	__transport_wait_for_tasks(cmd, true, aborted, tas, &flags);
2491 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2492 }
2493 
2494 int transport_generic_free_cmd(struct se_cmd *cmd, int wait_for_tasks)
2495 {
2496 	int ret = 0;
2497 	bool aborted = false, tas = false;
2498 
2499 	if (!(cmd->se_cmd_flags & SCF_SE_LUN_CMD)) {
2500 		if (wait_for_tasks && (cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
2501 			target_wait_free_cmd(cmd, &aborted, &tas);
2502 
2503 		if (!aborted || tas)
2504 			ret = transport_put_cmd(cmd);
2505 	} else {
2506 		if (wait_for_tasks)
2507 			target_wait_free_cmd(cmd, &aborted, &tas);
2508 		/*
2509 		 * Handle WRITE failure case where transport_generic_new_cmd()
2510 		 * has already added se_cmd to state_list, but fabric has
2511 		 * failed command before I/O submission.
2512 		 */
2513 		if (cmd->state_active)
2514 			target_remove_from_state_list(cmd);
2515 
2516 		if (cmd->se_lun)
2517 			transport_lun_remove_cmd(cmd);
2518 
2519 		if (!aborted || tas)
2520 			ret = transport_put_cmd(cmd);
2521 	}
2522 	/*
2523 	 * If the task has been internally aborted due to TMR ABORT_TASK
2524 	 * or LUN_RESET, target_core_tmr.c is responsible for performing
2525 	 * the remaining calls to target_put_sess_cmd(), and not the
2526 	 * callers of this function.
2527 	 */
2528 	if (aborted) {
2529 		pr_debug("Detected CMD_T_ABORTED for ITT: %llu\n", cmd->tag);
2530 		wait_for_completion(&cmd->cmd_wait_comp);
2531 		cmd->se_tfo->release_cmd(cmd);
2532 		ret = 1;
2533 	}
2534 	return ret;
2535 }
2536 EXPORT_SYMBOL(transport_generic_free_cmd);
2537 
2538 /* target_get_sess_cmd - Add command to active ->sess_cmd_list
2539  * @se_cmd:	command descriptor to add
2540  * @ack_kref:	Signal that fabric will perform an ack target_put_sess_cmd()
2541  */
2542 int target_get_sess_cmd(struct se_cmd *se_cmd, bool ack_kref)
2543 {
2544 	struct se_session *se_sess = se_cmd->se_sess;
2545 	unsigned long flags;
2546 	int ret = 0;
2547 
2548 	/*
2549 	 * Add a second kref if the fabric caller is expecting to handle
2550 	 * fabric acknowledgement that requires two target_put_sess_cmd()
2551 	 * invocations before se_cmd descriptor release.
2552 	 */
2553 	if (ack_kref) {
2554 		if (!kref_get_unless_zero(&se_cmd->cmd_kref))
2555 			return -EINVAL;
2556 
2557 		se_cmd->se_cmd_flags |= SCF_ACK_KREF;
2558 	}
2559 
2560 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2561 	if (se_sess->sess_tearing_down) {
2562 		ret = -ESHUTDOWN;
2563 		goto out;
2564 	}
2565 	list_add_tail(&se_cmd->se_cmd_list, &se_sess->sess_cmd_list);
2566 out:
2567 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2568 
2569 	if (ret && ack_kref)
2570 		target_put_sess_cmd(se_cmd);
2571 
2572 	return ret;
2573 }
2574 EXPORT_SYMBOL(target_get_sess_cmd);
2575 
2576 static void target_free_cmd_mem(struct se_cmd *cmd)
2577 {
2578 	transport_free_pages(cmd);
2579 
2580 	if (cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
2581 		core_tmr_release_req(cmd->se_tmr_req);
2582 	if (cmd->t_task_cdb != cmd->__t_task_cdb)
2583 		kfree(cmd->t_task_cdb);
2584 }
2585 
2586 static void target_release_cmd_kref(struct kref *kref)
2587 {
2588 	struct se_cmd *se_cmd = container_of(kref, struct se_cmd, cmd_kref);
2589 	struct se_session *se_sess = se_cmd->se_sess;
2590 	unsigned long flags;
2591 	bool fabric_stop;
2592 
2593 	if (se_sess) {
2594 		spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2595 
2596 		spin_lock(&se_cmd->t_state_lock);
2597 		fabric_stop = (se_cmd->transport_state & CMD_T_FABRIC_STOP) &&
2598 			      (se_cmd->transport_state & CMD_T_ABORTED);
2599 		spin_unlock(&se_cmd->t_state_lock);
2600 
2601 		if (se_cmd->cmd_wait_set || fabric_stop) {
2602 			list_del_init(&se_cmd->se_cmd_list);
2603 			spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2604 			target_free_cmd_mem(se_cmd);
2605 			complete(&se_cmd->cmd_wait_comp);
2606 			return;
2607 		}
2608 		list_del_init(&se_cmd->se_cmd_list);
2609 		spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2610 	}
2611 
2612 	target_free_cmd_mem(se_cmd);
2613 	se_cmd->se_tfo->release_cmd(se_cmd);
2614 }
2615 
2616 /**
2617  * target_put_sess_cmd - decrease the command reference count
2618  * @se_cmd:	command to drop a reference from
2619  *
2620  * Returns 1 if and only if this target_put_sess_cmd() call caused the
2621  * refcount to drop to zero. Returns zero otherwise.
2622  */
2623 int target_put_sess_cmd(struct se_cmd *se_cmd)
2624 {
2625 	return kref_put(&se_cmd->cmd_kref, target_release_cmd_kref);
2626 }
2627 EXPORT_SYMBOL(target_put_sess_cmd);
2628 
2629 /* target_sess_cmd_list_set_waiting - Flag all commands in
2630  *         sess_cmd_list to complete cmd_wait_comp.  Set
2631  *         sess_tearing_down so no more commands are queued.
2632  * @se_sess:	session to flag
2633  */
2634 void target_sess_cmd_list_set_waiting(struct se_session *se_sess)
2635 {
2636 	struct se_cmd *se_cmd, *tmp_cmd;
2637 	unsigned long flags;
2638 	int rc;
2639 
2640 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2641 	if (se_sess->sess_tearing_down) {
2642 		spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2643 		return;
2644 	}
2645 	se_sess->sess_tearing_down = 1;
2646 	list_splice_init(&se_sess->sess_cmd_list, &se_sess->sess_wait_list);
2647 
2648 	list_for_each_entry_safe(se_cmd, tmp_cmd,
2649 				 &se_sess->sess_wait_list, se_cmd_list) {
2650 		rc = kref_get_unless_zero(&se_cmd->cmd_kref);
2651 		if (rc) {
2652 			se_cmd->cmd_wait_set = 1;
2653 			spin_lock(&se_cmd->t_state_lock);
2654 			se_cmd->transport_state |= CMD_T_FABRIC_STOP;
2655 			spin_unlock(&se_cmd->t_state_lock);
2656 		} else
2657 			list_del_init(&se_cmd->se_cmd_list);
2658 	}
2659 
2660 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2661 }
2662 EXPORT_SYMBOL(target_sess_cmd_list_set_waiting);
2663 
2664 /* target_wait_for_sess_cmds - Wait for outstanding descriptors
2665  * @se_sess:    session to wait for active I/O
2666  */
2667 void target_wait_for_sess_cmds(struct se_session *se_sess)
2668 {
2669 	struct se_cmd *se_cmd, *tmp_cmd;
2670 	unsigned long flags;
2671 	bool tas;
2672 
2673 	list_for_each_entry_safe(se_cmd, tmp_cmd,
2674 				&se_sess->sess_wait_list, se_cmd_list) {
2675 		pr_debug("Waiting for se_cmd: %p t_state: %d, fabric state:"
2676 			" %d\n", se_cmd, se_cmd->t_state,
2677 			se_cmd->se_tfo->get_cmd_state(se_cmd));
2678 
2679 		spin_lock_irqsave(&se_cmd->t_state_lock, flags);
2680 		tas = (se_cmd->transport_state & CMD_T_TAS);
2681 		spin_unlock_irqrestore(&se_cmd->t_state_lock, flags);
2682 
2683 		if (!target_put_sess_cmd(se_cmd)) {
2684 			if (tas)
2685 				target_put_sess_cmd(se_cmd);
2686 		}
2687 
2688 		wait_for_completion(&se_cmd->cmd_wait_comp);
2689 		pr_debug("After cmd_wait_comp: se_cmd: %p t_state: %d"
2690 			" fabric state: %d\n", se_cmd, se_cmd->t_state,
2691 			se_cmd->se_tfo->get_cmd_state(se_cmd));
2692 
2693 		se_cmd->se_tfo->release_cmd(se_cmd);
2694 	}
2695 
2696 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2697 	WARN_ON(!list_empty(&se_sess->sess_cmd_list));
2698 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2699 
2700 }
2701 EXPORT_SYMBOL(target_wait_for_sess_cmds);
2702 
2703 static void target_lun_confirm(struct percpu_ref *ref)
2704 {
2705 	struct se_lun *lun = container_of(ref, struct se_lun, lun_ref);
2706 
2707 	complete(&lun->lun_ref_comp);
2708 }
2709 
2710 void transport_clear_lun_ref(struct se_lun *lun)
2711 {
2712 	/*
2713 	 * Mark the percpu-ref as DEAD, switch to atomic_t mode, drop
2714 	 * the initial reference and schedule confirm kill to be
2715 	 * executed after one full RCU grace period has completed.
2716 	 */
2717 	percpu_ref_kill_and_confirm(&lun->lun_ref, target_lun_confirm);
2718 	/*
2719 	 * The first completion waits for percpu_ref_switch_to_atomic_rcu()
2720 	 * to call target_lun_confirm after lun->lun_ref has been marked
2721 	 * as __PERCPU_REF_DEAD on all CPUs, and switches to atomic_t
2722 	 * mode so that percpu_ref_tryget_live() lookup of lun->lun_ref
2723 	 * fails for all new incoming I/O.
2724 	 */
2725 	wait_for_completion(&lun->lun_ref_comp);
2726 	/*
2727 	 * The second completion waits for percpu_ref_put_many() to
2728 	 * invoke ->release() after lun->lun_ref has switched to
2729 	 * atomic_t mode, and lun->lun_ref.count has reached zero.
2730 	 *
2731 	 * At this point all target-core lun->lun_ref references have
2732 	 * been dropped via transport_lun_remove_cmd(), and it's safe
2733 	 * to proceed with the remaining LUN shutdown.
2734 	 */
2735 	wait_for_completion(&lun->lun_shutdown_comp);
2736 }
2737 
2738 static bool
2739 __transport_wait_for_tasks(struct se_cmd *cmd, bool fabric_stop,
2740 			   bool *aborted, bool *tas, unsigned long *flags)
2741 	__releases(&cmd->t_state_lock)
2742 	__acquires(&cmd->t_state_lock)
2743 {
2744 
2745 	assert_spin_locked(&cmd->t_state_lock);
2746 	WARN_ON_ONCE(!irqs_disabled());
2747 
2748 	if (fabric_stop)
2749 		cmd->transport_state |= CMD_T_FABRIC_STOP;
2750 
2751 	if (cmd->transport_state & CMD_T_ABORTED)
2752 		*aborted = true;
2753 
2754 	if (cmd->transport_state & CMD_T_TAS)
2755 		*tas = true;
2756 
2757 	if (!(cmd->se_cmd_flags & SCF_SE_LUN_CMD) &&
2758 	    !(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
2759 		return false;
2760 
2761 	if (!(cmd->se_cmd_flags & SCF_SUPPORTED_SAM_OPCODE) &&
2762 	    !(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
2763 		return false;
2764 
2765 	if (!(cmd->transport_state & CMD_T_ACTIVE))
2766 		return false;
2767 
2768 	if (fabric_stop && *aborted)
2769 		return false;
2770 
2771 	cmd->transport_state |= CMD_T_STOP;
2772 
2773 	pr_debug("wait_for_tasks: Stopping %p ITT: 0x%08llx i_state: %d,"
2774 		 " t_state: %d, CMD_T_STOP\n", cmd, cmd->tag,
2775 		 cmd->se_tfo->get_cmd_state(cmd), cmd->t_state);
2776 
2777 	spin_unlock_irqrestore(&cmd->t_state_lock, *flags);
2778 
2779 	wait_for_completion(&cmd->t_transport_stop_comp);
2780 
2781 	spin_lock_irqsave(&cmd->t_state_lock, *flags);
2782 	cmd->transport_state &= ~(CMD_T_ACTIVE | CMD_T_STOP);
2783 
2784 	pr_debug("wait_for_tasks: Stopped wait_for_completion(&cmd->"
2785 		 "t_transport_stop_comp) for ITT: 0x%08llx\n", cmd->tag);
2786 
2787 	return true;
2788 }
2789 
2790 /**
2791  * transport_wait_for_tasks - set CMD_T_STOP and wait for t_transport_stop_comp
2792  * @cmd: command to wait on
2793  */
2794 bool transport_wait_for_tasks(struct se_cmd *cmd)
2795 {
2796 	unsigned long flags;
2797 	bool ret, aborted = false, tas = false;
2798 
2799 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2800 	ret = __transport_wait_for_tasks(cmd, false, &aborted, &tas, &flags);
2801 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2802 
2803 	return ret;
2804 }
2805 EXPORT_SYMBOL(transport_wait_for_tasks);
2806 
2807 struct sense_info {
2808 	u8 key;
2809 	u8 asc;
2810 	u8 ascq;
2811 	bool add_sector_info;
2812 };
2813 
2814 static const struct sense_info sense_info_table[] = {
2815 	[TCM_NO_SENSE] = {
2816 		.key = NOT_READY
2817 	},
2818 	[TCM_NON_EXISTENT_LUN] = {
2819 		.key = ILLEGAL_REQUEST,
2820 		.asc = 0x25 /* LOGICAL UNIT NOT SUPPORTED */
2821 	},
2822 	[TCM_UNSUPPORTED_SCSI_OPCODE] = {
2823 		.key = ILLEGAL_REQUEST,
2824 		.asc = 0x20, /* INVALID COMMAND OPERATION CODE */
2825 	},
2826 	[TCM_SECTOR_COUNT_TOO_MANY] = {
2827 		.key = ILLEGAL_REQUEST,
2828 		.asc = 0x20, /* INVALID COMMAND OPERATION CODE */
2829 	},
2830 	[TCM_UNKNOWN_MODE_PAGE] = {
2831 		.key = ILLEGAL_REQUEST,
2832 		.asc = 0x24, /* INVALID FIELD IN CDB */
2833 	},
2834 	[TCM_CHECK_CONDITION_ABORT_CMD] = {
2835 		.key = ABORTED_COMMAND,
2836 		.asc = 0x29, /* BUS DEVICE RESET FUNCTION OCCURRED */
2837 		.ascq = 0x03,
2838 	},
2839 	[TCM_INCORRECT_AMOUNT_OF_DATA] = {
2840 		.key = ABORTED_COMMAND,
2841 		.asc = 0x0c, /* WRITE ERROR */
2842 		.ascq = 0x0d, /* NOT ENOUGH UNSOLICITED DATA */
2843 	},
2844 	[TCM_INVALID_CDB_FIELD] = {
2845 		.key = ILLEGAL_REQUEST,
2846 		.asc = 0x24, /* INVALID FIELD IN CDB */
2847 	},
2848 	[TCM_INVALID_PARAMETER_LIST] = {
2849 		.key = ILLEGAL_REQUEST,
2850 		.asc = 0x26, /* INVALID FIELD IN PARAMETER LIST */
2851 	},
2852 	[TCM_TOO_MANY_TARGET_DESCS] = {
2853 		.key = ILLEGAL_REQUEST,
2854 		.asc = 0x26,
2855 		.ascq = 0x06, /* TOO MANY TARGET DESCRIPTORS */
2856 	},
2857 	[TCM_UNSUPPORTED_TARGET_DESC_TYPE_CODE] = {
2858 		.key = ILLEGAL_REQUEST,
2859 		.asc = 0x26,
2860 		.ascq = 0x07, /* UNSUPPORTED TARGET DESCRIPTOR TYPE CODE */
2861 	},
2862 	[TCM_TOO_MANY_SEGMENT_DESCS] = {
2863 		.key = ILLEGAL_REQUEST,
2864 		.asc = 0x26,
2865 		.ascq = 0x08, /* TOO MANY SEGMENT DESCRIPTORS */
2866 	},
2867 	[TCM_UNSUPPORTED_SEGMENT_DESC_TYPE_CODE] = {
2868 		.key = ILLEGAL_REQUEST,
2869 		.asc = 0x26,
2870 		.ascq = 0x09, /* UNSUPPORTED SEGMENT DESCRIPTOR TYPE CODE */
2871 	},
2872 	[TCM_PARAMETER_LIST_LENGTH_ERROR] = {
2873 		.key = ILLEGAL_REQUEST,
2874 		.asc = 0x1a, /* PARAMETER LIST LENGTH ERROR */
2875 	},
2876 	[TCM_UNEXPECTED_UNSOLICITED_DATA] = {
2877 		.key = ILLEGAL_REQUEST,
2878 		.asc = 0x0c, /* WRITE ERROR */
2879 		.ascq = 0x0c, /* UNEXPECTED_UNSOLICITED_DATA */
2880 	},
2881 	[TCM_SERVICE_CRC_ERROR] = {
2882 		.key = ABORTED_COMMAND,
2883 		.asc = 0x47, /* PROTOCOL SERVICE CRC ERROR */
2884 		.ascq = 0x05, /* N/A */
2885 	},
2886 	[TCM_SNACK_REJECTED] = {
2887 		.key = ABORTED_COMMAND,
2888 		.asc = 0x11, /* READ ERROR */
2889 		.ascq = 0x13, /* FAILED RETRANSMISSION REQUEST */
2890 	},
2891 	[TCM_WRITE_PROTECTED] = {
2892 		.key = DATA_PROTECT,
2893 		.asc = 0x27, /* WRITE PROTECTED */
2894 	},
2895 	[TCM_ADDRESS_OUT_OF_RANGE] = {
2896 		.key = ILLEGAL_REQUEST,
2897 		.asc = 0x21, /* LOGICAL BLOCK ADDRESS OUT OF RANGE */
2898 	},
2899 	[TCM_CHECK_CONDITION_UNIT_ATTENTION] = {
2900 		.key = UNIT_ATTENTION,
2901 	},
2902 	[TCM_CHECK_CONDITION_NOT_READY] = {
2903 		.key = NOT_READY,
2904 	},
2905 	[TCM_MISCOMPARE_VERIFY] = {
2906 		.key = MISCOMPARE,
2907 		.asc = 0x1d, /* MISCOMPARE DURING VERIFY OPERATION */
2908 		.ascq = 0x00,
2909 	},
2910 	[TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED] = {
2911 		.key = ABORTED_COMMAND,
2912 		.asc = 0x10,
2913 		.ascq = 0x01, /* LOGICAL BLOCK GUARD CHECK FAILED */
2914 		.add_sector_info = true,
2915 	},
2916 	[TCM_LOGICAL_BLOCK_APP_TAG_CHECK_FAILED] = {
2917 		.key = ABORTED_COMMAND,
2918 		.asc = 0x10,
2919 		.ascq = 0x02, /* LOGICAL BLOCK APPLICATION TAG CHECK FAILED */
2920 		.add_sector_info = true,
2921 	},
2922 	[TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED] = {
2923 		.key = ABORTED_COMMAND,
2924 		.asc = 0x10,
2925 		.ascq = 0x03, /* LOGICAL BLOCK REFERENCE TAG CHECK FAILED */
2926 		.add_sector_info = true,
2927 	},
2928 	[TCM_COPY_TARGET_DEVICE_NOT_REACHABLE] = {
2929 		.key = COPY_ABORTED,
2930 		.asc = 0x0d,
2931 		.ascq = 0x02, /* COPY TARGET DEVICE NOT REACHABLE */
2932 
2933 	},
2934 	[TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE] = {
2935 		/*
2936 		 * Returning ILLEGAL REQUEST would cause immediate IO errors on
2937 		 * Solaris initiators.  Returning NOT READY instead means the
2938 		 * operations will be retried a finite number of times and we
2939 		 * can survive intermittent errors.
2940 		 */
2941 		.key = NOT_READY,
2942 		.asc = 0x08, /* LOGICAL UNIT COMMUNICATION FAILURE */
2943 	},
2944 };
2945 
2946 static int translate_sense_reason(struct se_cmd *cmd, sense_reason_t reason)
2947 {
2948 	const struct sense_info *si;
2949 	u8 *buffer = cmd->sense_buffer;
2950 	int r = (__force int)reason;
2951 	u8 asc, ascq;
2952 	bool desc_format = target_sense_desc_format(cmd->se_dev);
2953 
2954 	if (r < ARRAY_SIZE(sense_info_table) && sense_info_table[r].key)
2955 		si = &sense_info_table[r];
2956 	else
2957 		si = &sense_info_table[(__force int)
2958 				       TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE];
2959 
2960 	if (reason == TCM_CHECK_CONDITION_UNIT_ATTENTION) {
2961 		core_scsi3_ua_for_check_condition(cmd, &asc, &ascq);
2962 		WARN_ON_ONCE(asc == 0);
2963 	} else if (si->asc == 0) {
2964 		WARN_ON_ONCE(cmd->scsi_asc == 0);
2965 		asc = cmd->scsi_asc;
2966 		ascq = cmd->scsi_ascq;
2967 	} else {
2968 		asc = si->asc;
2969 		ascq = si->ascq;
2970 	}
2971 
2972 	scsi_build_sense_buffer(desc_format, buffer, si->key, asc, ascq);
2973 	if (si->add_sector_info)
2974 		return scsi_set_sense_information(buffer,
2975 						  cmd->scsi_sense_length,
2976 						  cmd->bad_sector);
2977 
2978 	return 0;
2979 }
2980 
2981 int
2982 transport_send_check_condition_and_sense(struct se_cmd *cmd,
2983 		sense_reason_t reason, int from_transport)
2984 {
2985 	unsigned long flags;
2986 
2987 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2988 	if (cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION) {
2989 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2990 		return 0;
2991 	}
2992 	cmd->se_cmd_flags |= SCF_SENT_CHECK_CONDITION;
2993 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2994 
2995 	if (!from_transport) {
2996 		int rc;
2997 
2998 		cmd->se_cmd_flags |= SCF_EMULATED_TASK_SENSE;
2999 		cmd->scsi_status = SAM_STAT_CHECK_CONDITION;
3000 		cmd->scsi_sense_length  = TRANSPORT_SENSE_BUFFER;
3001 		rc = translate_sense_reason(cmd, reason);
3002 		if (rc)
3003 			return rc;
3004 	}
3005 
3006 	trace_target_cmd_complete(cmd);
3007 	return cmd->se_tfo->queue_status(cmd);
3008 }
3009 EXPORT_SYMBOL(transport_send_check_condition_and_sense);
3010 
3011 static int __transport_check_aborted_status(struct se_cmd *cmd, int send_status)
3012 	__releases(&cmd->t_state_lock)
3013 	__acquires(&cmd->t_state_lock)
3014 {
3015 	assert_spin_locked(&cmd->t_state_lock);
3016 	WARN_ON_ONCE(!irqs_disabled());
3017 
3018 	if (!(cmd->transport_state & CMD_T_ABORTED))
3019 		return 0;
3020 	/*
3021 	 * If cmd has been aborted but either no status is to be sent or it has
3022 	 * already been sent, just return
3023 	 */
3024 	if (!send_status || !(cmd->se_cmd_flags & SCF_SEND_DELAYED_TAS)) {
3025 		if (send_status)
3026 			cmd->se_cmd_flags |= SCF_SEND_DELAYED_TAS;
3027 		return 1;
3028 	}
3029 
3030 	pr_debug("Sending delayed SAM_STAT_TASK_ABORTED status for CDB:"
3031 		" 0x%02x ITT: 0x%08llx\n", cmd->t_task_cdb[0], cmd->tag);
3032 
3033 	cmd->se_cmd_flags &= ~SCF_SEND_DELAYED_TAS;
3034 	cmd->scsi_status = SAM_STAT_TASK_ABORTED;
3035 	trace_target_cmd_complete(cmd);
3036 
3037 	spin_unlock_irq(&cmd->t_state_lock);
3038 	cmd->se_tfo->queue_status(cmd);
3039 	spin_lock_irq(&cmd->t_state_lock);
3040 
3041 	return 1;
3042 }
3043 
3044 int transport_check_aborted_status(struct se_cmd *cmd, int send_status)
3045 {
3046 	int ret;
3047 
3048 	spin_lock_irq(&cmd->t_state_lock);
3049 	ret = __transport_check_aborted_status(cmd, send_status);
3050 	spin_unlock_irq(&cmd->t_state_lock);
3051 
3052 	return ret;
3053 }
3054 EXPORT_SYMBOL(transport_check_aborted_status);
3055 
3056 void transport_send_task_abort(struct se_cmd *cmd)
3057 {
3058 	unsigned long flags;
3059 
3060 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3061 	if (cmd->se_cmd_flags & (SCF_SENT_CHECK_CONDITION)) {
3062 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3063 		return;
3064 	}
3065 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3066 
3067 	/*
3068 	 * If there are still expected incoming fabric WRITEs, we wait
3069 	 * until until they have completed before sending a TASK_ABORTED
3070 	 * response.  This response with TASK_ABORTED status will be
3071 	 * queued back to fabric module by transport_check_aborted_status().
3072 	 */
3073 	if (cmd->data_direction == DMA_TO_DEVICE) {
3074 		if (cmd->se_tfo->write_pending_status(cmd) != 0) {
3075 			spin_lock_irqsave(&cmd->t_state_lock, flags);
3076 			if (cmd->se_cmd_flags & SCF_SEND_DELAYED_TAS) {
3077 				spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3078 				goto send_abort;
3079 			}
3080 			cmd->se_cmd_flags |= SCF_SEND_DELAYED_TAS;
3081 			spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3082 			return;
3083 		}
3084 	}
3085 send_abort:
3086 	cmd->scsi_status = SAM_STAT_TASK_ABORTED;
3087 
3088 	transport_lun_remove_cmd(cmd);
3089 
3090 	pr_debug("Setting SAM_STAT_TASK_ABORTED status for CDB: 0x%02x, ITT: 0x%08llx\n",
3091 		 cmd->t_task_cdb[0], cmd->tag);
3092 
3093 	trace_target_cmd_complete(cmd);
3094 	cmd->se_tfo->queue_status(cmd);
3095 }
3096 
3097 static void target_tmr_work(struct work_struct *work)
3098 {
3099 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
3100 	struct se_device *dev = cmd->se_dev;
3101 	struct se_tmr_req *tmr = cmd->se_tmr_req;
3102 	unsigned long flags;
3103 	int ret;
3104 
3105 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3106 	if (cmd->transport_state & CMD_T_ABORTED) {
3107 		tmr->response = TMR_FUNCTION_REJECTED;
3108 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3109 		goto check_stop;
3110 	}
3111 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3112 
3113 	switch (tmr->function) {
3114 	case TMR_ABORT_TASK:
3115 		core_tmr_abort_task(dev, tmr, cmd->se_sess);
3116 		break;
3117 	case TMR_ABORT_TASK_SET:
3118 	case TMR_CLEAR_ACA:
3119 	case TMR_CLEAR_TASK_SET:
3120 		tmr->response = TMR_TASK_MGMT_FUNCTION_NOT_SUPPORTED;
3121 		break;
3122 	case TMR_LUN_RESET:
3123 		ret = core_tmr_lun_reset(dev, tmr, NULL, NULL);
3124 		tmr->response = (!ret) ? TMR_FUNCTION_COMPLETE :
3125 					 TMR_FUNCTION_REJECTED;
3126 		if (tmr->response == TMR_FUNCTION_COMPLETE) {
3127 			target_ua_allocate_lun(cmd->se_sess->se_node_acl,
3128 					       cmd->orig_fe_lun, 0x29,
3129 					       ASCQ_29H_BUS_DEVICE_RESET_FUNCTION_OCCURRED);
3130 		}
3131 		break;
3132 	case TMR_TARGET_WARM_RESET:
3133 		tmr->response = TMR_FUNCTION_REJECTED;
3134 		break;
3135 	case TMR_TARGET_COLD_RESET:
3136 		tmr->response = TMR_FUNCTION_REJECTED;
3137 		break;
3138 	default:
3139 		pr_err("Uknown TMR function: 0x%02x.\n",
3140 				tmr->function);
3141 		tmr->response = TMR_FUNCTION_REJECTED;
3142 		break;
3143 	}
3144 
3145 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3146 	if (cmd->transport_state & CMD_T_ABORTED) {
3147 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3148 		goto check_stop;
3149 	}
3150 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3151 
3152 	cmd->se_tfo->queue_tm_rsp(cmd);
3153 
3154 check_stop:
3155 	transport_cmd_check_stop_to_fabric(cmd);
3156 }
3157 
3158 int transport_generic_handle_tmr(
3159 	struct se_cmd *cmd)
3160 {
3161 	unsigned long flags;
3162 	bool aborted = false;
3163 
3164 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3165 	if (cmd->transport_state & CMD_T_ABORTED) {
3166 		aborted = true;
3167 	} else {
3168 		cmd->t_state = TRANSPORT_ISTATE_PROCESSING;
3169 		cmd->transport_state |= CMD_T_ACTIVE;
3170 	}
3171 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3172 
3173 	if (aborted) {
3174 		pr_warn_ratelimited("handle_tmr caught CMD_T_ABORTED TMR %d"
3175 			"ref_tag: %llu tag: %llu\n", cmd->se_tmr_req->function,
3176 			cmd->se_tmr_req->ref_task_tag, cmd->tag);
3177 		transport_cmd_check_stop_to_fabric(cmd);
3178 		return 0;
3179 	}
3180 
3181 	INIT_WORK(&cmd->work, target_tmr_work);
3182 	queue_work(cmd->se_dev->tmr_wq, &cmd->work);
3183 	return 0;
3184 }
3185 EXPORT_SYMBOL(transport_generic_handle_tmr);
3186 
3187 bool
3188 target_check_wce(struct se_device *dev)
3189 {
3190 	bool wce = false;
3191 
3192 	if (dev->transport->get_write_cache)
3193 		wce = dev->transport->get_write_cache(dev);
3194 	else if (dev->dev_attrib.emulate_write_cache > 0)
3195 		wce = true;
3196 
3197 	return wce;
3198 }
3199 
3200 bool
3201 target_check_fua(struct se_device *dev)
3202 {
3203 	return target_check_wce(dev) && dev->dev_attrib.emulate_fua_write > 0;
3204 }
3205