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