xref: /linux/drivers/target/target_core_transport.c (revision e5c86679d5e864947a52fb31e45a425dea3e7fa9)
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 int translate_sense_reason(struct se_cmd *cmd, sense_reason_t reason);
68 static void transport_handle_queue_full(struct se_cmd *cmd,
69 		struct se_device *dev, int err, bool write_pending);
70 static int transport_put_cmd(struct se_cmd *cmd);
71 static void target_complete_ok_work(struct work_struct *work);
72 
73 int init_se_kmem_caches(void)
74 {
75 	se_sess_cache = kmem_cache_create("se_sess_cache",
76 			sizeof(struct se_session), __alignof__(struct se_session),
77 			0, NULL);
78 	if (!se_sess_cache) {
79 		pr_err("kmem_cache_create() for struct se_session"
80 				" failed\n");
81 		goto out;
82 	}
83 	se_ua_cache = kmem_cache_create("se_ua_cache",
84 			sizeof(struct se_ua), __alignof__(struct se_ua),
85 			0, NULL);
86 	if (!se_ua_cache) {
87 		pr_err("kmem_cache_create() for struct se_ua failed\n");
88 		goto out_free_sess_cache;
89 	}
90 	t10_pr_reg_cache = kmem_cache_create("t10_pr_reg_cache",
91 			sizeof(struct t10_pr_registration),
92 			__alignof__(struct t10_pr_registration), 0, NULL);
93 	if (!t10_pr_reg_cache) {
94 		pr_err("kmem_cache_create() for struct t10_pr_registration"
95 				" failed\n");
96 		goto out_free_ua_cache;
97 	}
98 	t10_alua_lu_gp_cache = kmem_cache_create("t10_alua_lu_gp_cache",
99 			sizeof(struct t10_alua_lu_gp), __alignof__(struct t10_alua_lu_gp),
100 			0, NULL);
101 	if (!t10_alua_lu_gp_cache) {
102 		pr_err("kmem_cache_create() for t10_alua_lu_gp_cache"
103 				" failed\n");
104 		goto out_free_pr_reg_cache;
105 	}
106 	t10_alua_lu_gp_mem_cache = kmem_cache_create("t10_alua_lu_gp_mem_cache",
107 			sizeof(struct t10_alua_lu_gp_member),
108 			__alignof__(struct t10_alua_lu_gp_member), 0, NULL);
109 	if (!t10_alua_lu_gp_mem_cache) {
110 		pr_err("kmem_cache_create() for t10_alua_lu_gp_mem_"
111 				"cache failed\n");
112 		goto out_free_lu_gp_cache;
113 	}
114 	t10_alua_tg_pt_gp_cache = kmem_cache_create("t10_alua_tg_pt_gp_cache",
115 			sizeof(struct t10_alua_tg_pt_gp),
116 			__alignof__(struct t10_alua_tg_pt_gp), 0, NULL);
117 	if (!t10_alua_tg_pt_gp_cache) {
118 		pr_err("kmem_cache_create() for t10_alua_tg_pt_gp_"
119 				"cache failed\n");
120 		goto out_free_lu_gp_mem_cache;
121 	}
122 	t10_alua_lba_map_cache = kmem_cache_create(
123 			"t10_alua_lba_map_cache",
124 			sizeof(struct t10_alua_lba_map),
125 			__alignof__(struct t10_alua_lba_map), 0, NULL);
126 	if (!t10_alua_lba_map_cache) {
127 		pr_err("kmem_cache_create() for t10_alua_lba_map_"
128 				"cache failed\n");
129 		goto out_free_tg_pt_gp_cache;
130 	}
131 	t10_alua_lba_map_mem_cache = kmem_cache_create(
132 			"t10_alua_lba_map_mem_cache",
133 			sizeof(struct t10_alua_lba_map_member),
134 			__alignof__(struct t10_alua_lba_map_member), 0, NULL);
135 	if (!t10_alua_lba_map_mem_cache) {
136 		pr_err("kmem_cache_create() for t10_alua_lba_map_mem_"
137 				"cache failed\n");
138 		goto out_free_lba_map_cache;
139 	}
140 
141 	target_completion_wq = alloc_workqueue("target_completion",
142 					       WQ_MEM_RECLAIM, 0);
143 	if (!target_completion_wq)
144 		goto out_free_lba_map_mem_cache;
145 
146 	return 0;
147 
148 out_free_lba_map_mem_cache:
149 	kmem_cache_destroy(t10_alua_lba_map_mem_cache);
150 out_free_lba_map_cache:
151 	kmem_cache_destroy(t10_alua_lba_map_cache);
152 out_free_tg_pt_gp_cache:
153 	kmem_cache_destroy(t10_alua_tg_pt_gp_cache);
154 out_free_lu_gp_mem_cache:
155 	kmem_cache_destroy(t10_alua_lu_gp_mem_cache);
156 out_free_lu_gp_cache:
157 	kmem_cache_destroy(t10_alua_lu_gp_cache);
158 out_free_pr_reg_cache:
159 	kmem_cache_destroy(t10_pr_reg_cache);
160 out_free_ua_cache:
161 	kmem_cache_destroy(se_ua_cache);
162 out_free_sess_cache:
163 	kmem_cache_destroy(se_sess_cache);
164 out:
165 	return -ENOMEM;
166 }
167 
168 void release_se_kmem_caches(void)
169 {
170 	destroy_workqueue(target_completion_wq);
171 	kmem_cache_destroy(se_sess_cache);
172 	kmem_cache_destroy(se_ua_cache);
173 	kmem_cache_destroy(t10_pr_reg_cache);
174 	kmem_cache_destroy(t10_alua_lu_gp_cache);
175 	kmem_cache_destroy(t10_alua_lu_gp_mem_cache);
176 	kmem_cache_destroy(t10_alua_tg_pt_gp_cache);
177 	kmem_cache_destroy(t10_alua_lba_map_cache);
178 	kmem_cache_destroy(t10_alua_lba_map_mem_cache);
179 }
180 
181 /* This code ensures unique mib indexes are handed out. */
182 static DEFINE_SPINLOCK(scsi_mib_index_lock);
183 static u32 scsi_mib_index[SCSI_INDEX_TYPE_MAX];
184 
185 /*
186  * Allocate a new row index for the entry type specified
187  */
188 u32 scsi_get_new_index(scsi_index_t type)
189 {
190 	u32 new_index;
191 
192 	BUG_ON((type < 0) || (type >= SCSI_INDEX_TYPE_MAX));
193 
194 	spin_lock(&scsi_mib_index_lock);
195 	new_index = ++scsi_mib_index[type];
196 	spin_unlock(&scsi_mib_index_lock);
197 
198 	return new_index;
199 }
200 
201 void transport_subsystem_check_init(void)
202 {
203 	int ret;
204 	static int sub_api_initialized;
205 
206 	if (sub_api_initialized)
207 		return;
208 
209 	ret = request_module("target_core_iblock");
210 	if (ret != 0)
211 		pr_err("Unable to load target_core_iblock\n");
212 
213 	ret = request_module("target_core_file");
214 	if (ret != 0)
215 		pr_err("Unable to load target_core_file\n");
216 
217 	ret = request_module("target_core_pscsi");
218 	if (ret != 0)
219 		pr_err("Unable to load target_core_pscsi\n");
220 
221 	ret = request_module("target_core_user");
222 	if (ret != 0)
223 		pr_err("Unable to load target_core_user\n");
224 
225 	sub_api_initialized = 1;
226 }
227 
228 struct se_session *transport_init_session(enum target_prot_op sup_prot_ops)
229 {
230 	struct se_session *se_sess;
231 
232 	se_sess = kmem_cache_zalloc(se_sess_cache, GFP_KERNEL);
233 	if (!se_sess) {
234 		pr_err("Unable to allocate struct se_session from"
235 				" se_sess_cache\n");
236 		return ERR_PTR(-ENOMEM);
237 	}
238 	INIT_LIST_HEAD(&se_sess->sess_list);
239 	INIT_LIST_HEAD(&se_sess->sess_acl_list);
240 	INIT_LIST_HEAD(&se_sess->sess_cmd_list);
241 	INIT_LIST_HEAD(&se_sess->sess_wait_list);
242 	spin_lock_init(&se_sess->sess_cmd_lock);
243 	se_sess->sup_prot_ops = sup_prot_ops;
244 
245 	return se_sess;
246 }
247 EXPORT_SYMBOL(transport_init_session);
248 
249 int transport_alloc_session_tags(struct se_session *se_sess,
250 			         unsigned int tag_num, unsigned int tag_size)
251 {
252 	int rc;
253 
254 	se_sess->sess_cmd_map = kzalloc(tag_num * tag_size,
255 					GFP_KERNEL | __GFP_NOWARN | __GFP_REPEAT);
256 	if (!se_sess->sess_cmd_map) {
257 		se_sess->sess_cmd_map = vzalloc(tag_num * tag_size);
258 		if (!se_sess->sess_cmd_map) {
259 			pr_err("Unable to allocate se_sess->sess_cmd_map\n");
260 			return -ENOMEM;
261 		}
262 	}
263 
264 	rc = percpu_ida_init(&se_sess->sess_tag_pool, tag_num);
265 	if (rc < 0) {
266 		pr_err("Unable to init se_sess->sess_tag_pool,"
267 			" tag_num: %u\n", tag_num);
268 		kvfree(se_sess->sess_cmd_map);
269 		se_sess->sess_cmd_map = NULL;
270 		return -ENOMEM;
271 	}
272 
273 	return 0;
274 }
275 EXPORT_SYMBOL(transport_alloc_session_tags);
276 
277 struct se_session *transport_init_session_tags(unsigned int tag_num,
278 					       unsigned int tag_size,
279 					       enum target_prot_op sup_prot_ops)
280 {
281 	struct se_session *se_sess;
282 	int rc;
283 
284 	if (tag_num != 0 && !tag_size) {
285 		pr_err("init_session_tags called with percpu-ida tag_num:"
286 		       " %u, but zero tag_size\n", tag_num);
287 		return ERR_PTR(-EINVAL);
288 	}
289 	if (!tag_num && tag_size) {
290 		pr_err("init_session_tags called with percpu-ida tag_size:"
291 		       " %u, but zero tag_num\n", tag_size);
292 		return ERR_PTR(-EINVAL);
293 	}
294 
295 	se_sess = transport_init_session(sup_prot_ops);
296 	if (IS_ERR(se_sess))
297 		return se_sess;
298 
299 	rc = transport_alloc_session_tags(se_sess, tag_num, tag_size);
300 	if (rc < 0) {
301 		transport_free_session(se_sess);
302 		return ERR_PTR(-ENOMEM);
303 	}
304 
305 	return se_sess;
306 }
307 EXPORT_SYMBOL(transport_init_session_tags);
308 
309 /*
310  * Called with spin_lock_irqsave(&struct se_portal_group->session_lock called.
311  */
312 void __transport_register_session(
313 	struct se_portal_group *se_tpg,
314 	struct se_node_acl *se_nacl,
315 	struct se_session *se_sess,
316 	void *fabric_sess_ptr)
317 {
318 	const struct target_core_fabric_ops *tfo = se_tpg->se_tpg_tfo;
319 	unsigned char buf[PR_REG_ISID_LEN];
320 
321 	se_sess->se_tpg = se_tpg;
322 	se_sess->fabric_sess_ptr = fabric_sess_ptr;
323 	/*
324 	 * Used by struct se_node_acl's under ConfigFS to locate active se_session-t
325 	 *
326 	 * Only set for struct se_session's that will actually be moving I/O.
327 	 * eg: *NOT* discovery sessions.
328 	 */
329 	if (se_nacl) {
330 		/*
331 		 *
332 		 * Determine if fabric allows for T10-PI feature bits exposed to
333 		 * initiators for device backends with !dev->dev_attrib.pi_prot_type.
334 		 *
335 		 * If so, then always save prot_type on a per se_node_acl node
336 		 * basis and re-instate the previous sess_prot_type to avoid
337 		 * disabling PI from below any previously initiator side
338 		 * registered LUNs.
339 		 */
340 		if (se_nacl->saved_prot_type)
341 			se_sess->sess_prot_type = se_nacl->saved_prot_type;
342 		else if (tfo->tpg_check_prot_fabric_only)
343 			se_sess->sess_prot_type = se_nacl->saved_prot_type =
344 					tfo->tpg_check_prot_fabric_only(se_tpg);
345 		/*
346 		 * If the fabric module supports an ISID based TransportID,
347 		 * save this value in binary from the fabric I_T Nexus now.
348 		 */
349 		if (se_tpg->se_tpg_tfo->sess_get_initiator_sid != NULL) {
350 			memset(&buf[0], 0, PR_REG_ISID_LEN);
351 			se_tpg->se_tpg_tfo->sess_get_initiator_sid(se_sess,
352 					&buf[0], PR_REG_ISID_LEN);
353 			se_sess->sess_bin_isid = get_unaligned_be64(&buf[0]);
354 		}
355 
356 		spin_lock_irq(&se_nacl->nacl_sess_lock);
357 		/*
358 		 * The se_nacl->nacl_sess pointer will be set to the
359 		 * last active I_T Nexus for each struct se_node_acl.
360 		 */
361 		se_nacl->nacl_sess = se_sess;
362 
363 		list_add_tail(&se_sess->sess_acl_list,
364 			      &se_nacl->acl_sess_list);
365 		spin_unlock_irq(&se_nacl->nacl_sess_lock);
366 	}
367 	list_add_tail(&se_sess->sess_list, &se_tpg->tpg_sess_list);
368 
369 	pr_debug("TARGET_CORE[%s]: Registered fabric_sess_ptr: %p\n",
370 		se_tpg->se_tpg_tfo->get_fabric_name(), se_sess->fabric_sess_ptr);
371 }
372 EXPORT_SYMBOL(__transport_register_session);
373 
374 void transport_register_session(
375 	struct se_portal_group *se_tpg,
376 	struct se_node_acl *se_nacl,
377 	struct se_session *se_sess,
378 	void *fabric_sess_ptr)
379 {
380 	unsigned long flags;
381 
382 	spin_lock_irqsave(&se_tpg->session_lock, flags);
383 	__transport_register_session(se_tpg, se_nacl, se_sess, fabric_sess_ptr);
384 	spin_unlock_irqrestore(&se_tpg->session_lock, flags);
385 }
386 EXPORT_SYMBOL(transport_register_session);
387 
388 struct se_session *
389 target_alloc_session(struct se_portal_group *tpg,
390 		     unsigned int tag_num, unsigned int tag_size,
391 		     enum target_prot_op prot_op,
392 		     const char *initiatorname, void *private,
393 		     int (*callback)(struct se_portal_group *,
394 				     struct se_session *, void *))
395 {
396 	struct se_session *sess;
397 
398 	/*
399 	 * If the fabric driver is using percpu-ida based pre allocation
400 	 * of I/O descriptor tags, go ahead and perform that setup now..
401 	 */
402 	if (tag_num != 0)
403 		sess = transport_init_session_tags(tag_num, tag_size, prot_op);
404 	else
405 		sess = transport_init_session(prot_op);
406 
407 	if (IS_ERR(sess))
408 		return sess;
409 
410 	sess->se_node_acl = core_tpg_check_initiator_node_acl(tpg,
411 					(unsigned char *)initiatorname);
412 	if (!sess->se_node_acl) {
413 		transport_free_session(sess);
414 		return ERR_PTR(-EACCES);
415 	}
416 	/*
417 	 * Go ahead and perform any remaining fabric setup that is
418 	 * required before transport_register_session().
419 	 */
420 	if (callback != NULL) {
421 		int rc = callback(tpg, sess, private);
422 		if (rc) {
423 			transport_free_session(sess);
424 			return ERR_PTR(rc);
425 		}
426 	}
427 
428 	transport_register_session(tpg, sess->se_node_acl, sess, private);
429 	return sess;
430 }
431 EXPORT_SYMBOL(target_alloc_session);
432 
433 ssize_t target_show_dynamic_sessions(struct se_portal_group *se_tpg, char *page)
434 {
435 	struct se_session *se_sess;
436 	ssize_t len = 0;
437 
438 	spin_lock_bh(&se_tpg->session_lock);
439 	list_for_each_entry(se_sess, &se_tpg->tpg_sess_list, sess_list) {
440 		if (!se_sess->se_node_acl)
441 			continue;
442 		if (!se_sess->se_node_acl->dynamic_node_acl)
443 			continue;
444 		if (strlen(se_sess->se_node_acl->initiatorname) + 1 + len > PAGE_SIZE)
445 			break;
446 
447 		len += snprintf(page + len, PAGE_SIZE - len, "%s\n",
448 				se_sess->se_node_acl->initiatorname);
449 		len += 1; /* Include NULL terminator */
450 	}
451 	spin_unlock_bh(&se_tpg->session_lock);
452 
453 	return len;
454 }
455 EXPORT_SYMBOL(target_show_dynamic_sessions);
456 
457 static void target_complete_nacl(struct kref *kref)
458 {
459 	struct se_node_acl *nacl = container_of(kref,
460 				struct se_node_acl, acl_kref);
461 	struct se_portal_group *se_tpg = nacl->se_tpg;
462 
463 	if (!nacl->dynamic_stop) {
464 		complete(&nacl->acl_free_comp);
465 		return;
466 	}
467 
468 	mutex_lock(&se_tpg->acl_node_mutex);
469 	list_del(&nacl->acl_list);
470 	mutex_unlock(&se_tpg->acl_node_mutex);
471 
472 	core_tpg_wait_for_nacl_pr_ref(nacl);
473 	core_free_device_list_for_node(nacl, se_tpg);
474 	kfree(nacl);
475 }
476 
477 void target_put_nacl(struct se_node_acl *nacl)
478 {
479 	kref_put(&nacl->acl_kref, target_complete_nacl);
480 }
481 EXPORT_SYMBOL(target_put_nacl);
482 
483 void transport_deregister_session_configfs(struct se_session *se_sess)
484 {
485 	struct se_node_acl *se_nacl;
486 	unsigned long flags;
487 	/*
488 	 * Used by struct se_node_acl's under ConfigFS to locate active struct se_session
489 	 */
490 	se_nacl = se_sess->se_node_acl;
491 	if (se_nacl) {
492 		spin_lock_irqsave(&se_nacl->nacl_sess_lock, flags);
493 		if (!list_empty(&se_sess->sess_acl_list))
494 			list_del_init(&se_sess->sess_acl_list);
495 		/*
496 		 * If the session list is empty, then clear the pointer.
497 		 * Otherwise, set the struct se_session pointer from the tail
498 		 * element of the per struct se_node_acl active session list.
499 		 */
500 		if (list_empty(&se_nacl->acl_sess_list))
501 			se_nacl->nacl_sess = NULL;
502 		else {
503 			se_nacl->nacl_sess = container_of(
504 					se_nacl->acl_sess_list.prev,
505 					struct se_session, sess_acl_list);
506 		}
507 		spin_unlock_irqrestore(&se_nacl->nacl_sess_lock, flags);
508 	}
509 }
510 EXPORT_SYMBOL(transport_deregister_session_configfs);
511 
512 void transport_free_session(struct se_session *se_sess)
513 {
514 	struct se_node_acl *se_nacl = se_sess->se_node_acl;
515 
516 	/*
517 	 * Drop the se_node_acl->nacl_kref obtained from within
518 	 * core_tpg_get_initiator_node_acl().
519 	 */
520 	if (se_nacl) {
521 		struct se_portal_group *se_tpg = se_nacl->se_tpg;
522 		const struct target_core_fabric_ops *se_tfo = se_tpg->se_tpg_tfo;
523 		unsigned long flags;
524 
525 		se_sess->se_node_acl = NULL;
526 
527 		/*
528 		 * Also determine if we need to drop the extra ->cmd_kref if
529 		 * it had been previously dynamically generated, and
530 		 * the endpoint is not caching dynamic ACLs.
531 		 */
532 		mutex_lock(&se_tpg->acl_node_mutex);
533 		if (se_nacl->dynamic_node_acl &&
534 		    !se_tfo->tpg_check_demo_mode_cache(se_tpg)) {
535 			spin_lock_irqsave(&se_nacl->nacl_sess_lock, flags);
536 			if (list_empty(&se_nacl->acl_sess_list))
537 				se_nacl->dynamic_stop = true;
538 			spin_unlock_irqrestore(&se_nacl->nacl_sess_lock, flags);
539 
540 			if (se_nacl->dynamic_stop)
541 				list_del(&se_nacl->acl_list);
542 		}
543 		mutex_unlock(&se_tpg->acl_node_mutex);
544 
545 		if (se_nacl->dynamic_stop)
546 			target_put_nacl(se_nacl);
547 
548 		target_put_nacl(se_nacl);
549 	}
550 	if (se_sess->sess_cmd_map) {
551 		percpu_ida_destroy(&se_sess->sess_tag_pool);
552 		kvfree(se_sess->sess_cmd_map);
553 	}
554 	kmem_cache_free(se_sess_cache, se_sess);
555 }
556 EXPORT_SYMBOL(transport_free_session);
557 
558 void transport_deregister_session(struct se_session *se_sess)
559 {
560 	struct se_portal_group *se_tpg = se_sess->se_tpg;
561 	unsigned long flags;
562 
563 	if (!se_tpg) {
564 		transport_free_session(se_sess);
565 		return;
566 	}
567 
568 	spin_lock_irqsave(&se_tpg->session_lock, flags);
569 	list_del(&se_sess->sess_list);
570 	se_sess->se_tpg = NULL;
571 	se_sess->fabric_sess_ptr = NULL;
572 	spin_unlock_irqrestore(&se_tpg->session_lock, flags);
573 
574 	pr_debug("TARGET_CORE[%s]: Deregistered fabric_sess\n",
575 		se_tpg->se_tpg_tfo->get_fabric_name());
576 	/*
577 	 * If last kref is dropping now for an explicit NodeACL, awake sleeping
578 	 * ->acl_free_comp caller to wakeup configfs se_node_acl->acl_group
579 	 * removal context from within transport_free_session() code.
580 	 *
581 	 * For dynamic ACL, target_put_nacl() uses target_complete_nacl()
582 	 * to release all remaining generate_node_acl=1 created ACL resources.
583 	 */
584 
585 	transport_free_session(se_sess);
586 }
587 EXPORT_SYMBOL(transport_deregister_session);
588 
589 static void target_remove_from_state_list(struct se_cmd *cmd)
590 {
591 	struct se_device *dev = cmd->se_dev;
592 	unsigned long flags;
593 
594 	if (!dev)
595 		return;
596 
597 	spin_lock_irqsave(&dev->execute_task_lock, flags);
598 	if (cmd->state_active) {
599 		list_del(&cmd->state_list);
600 		cmd->state_active = false;
601 	}
602 	spin_unlock_irqrestore(&dev->execute_task_lock, flags);
603 }
604 
605 static int transport_cmd_check_stop_to_fabric(struct se_cmd *cmd)
606 {
607 	unsigned long flags;
608 
609 	target_remove_from_state_list(cmd);
610 
611 	/*
612 	 * Clear struct se_cmd->se_lun before the handoff to FE.
613 	 */
614 	cmd->se_lun = NULL;
615 
616 	spin_lock_irqsave(&cmd->t_state_lock, flags);
617 	/*
618 	 * Determine if frontend context caller is requesting the stopping of
619 	 * this command for frontend exceptions.
620 	 */
621 	if (cmd->transport_state & CMD_T_STOP) {
622 		pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08llx\n",
623 			__func__, __LINE__, cmd->tag);
624 
625 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
626 
627 		complete_all(&cmd->t_transport_stop_comp);
628 		return 1;
629 	}
630 	cmd->transport_state &= ~CMD_T_ACTIVE;
631 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
632 
633 	/*
634 	 * Some fabric modules like tcm_loop can release their internally
635 	 * allocated I/O reference and struct se_cmd now.
636 	 *
637 	 * Fabric modules are expected to return '1' here if the se_cmd being
638 	 * passed is released at this point, or zero if not being released.
639 	 */
640 	return cmd->se_tfo->check_stop_free(cmd);
641 }
642 
643 static void transport_lun_remove_cmd(struct se_cmd *cmd)
644 {
645 	struct se_lun *lun = cmd->se_lun;
646 
647 	if (!lun)
648 		return;
649 
650 	if (cmpxchg(&cmd->lun_ref_active, true, false))
651 		percpu_ref_put(&lun->lun_ref);
652 }
653 
654 void transport_cmd_finish_abort(struct se_cmd *cmd, int remove)
655 {
656 	bool ack_kref = (cmd->se_cmd_flags & SCF_ACK_KREF);
657 
658 	if (cmd->se_cmd_flags & SCF_SE_LUN_CMD)
659 		transport_lun_remove_cmd(cmd);
660 	/*
661 	 * Allow the fabric driver to unmap any resources before
662 	 * releasing the descriptor via TFO->release_cmd()
663 	 */
664 	if (remove)
665 		cmd->se_tfo->aborted_task(cmd);
666 
667 	if (transport_cmd_check_stop_to_fabric(cmd))
668 		return;
669 	if (remove && ack_kref)
670 		transport_put_cmd(cmd);
671 }
672 
673 static void target_complete_failure_work(struct work_struct *work)
674 {
675 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
676 
677 	transport_generic_request_failure(cmd,
678 			TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE);
679 }
680 
681 /*
682  * Used when asking transport to copy Sense Data from the underlying
683  * Linux/SCSI struct scsi_cmnd
684  */
685 static unsigned char *transport_get_sense_buffer(struct se_cmd *cmd)
686 {
687 	struct se_device *dev = cmd->se_dev;
688 
689 	WARN_ON(!cmd->se_lun);
690 
691 	if (!dev)
692 		return NULL;
693 
694 	if (cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION)
695 		return NULL;
696 
697 	cmd->scsi_sense_length = TRANSPORT_SENSE_BUFFER;
698 
699 	pr_debug("HBA_[%u]_PLUG[%s]: Requesting sense for SAM STATUS: 0x%02x\n",
700 		dev->se_hba->hba_id, dev->transport->name, cmd->scsi_status);
701 	return cmd->sense_buffer;
702 }
703 
704 void target_complete_cmd(struct se_cmd *cmd, u8 scsi_status)
705 {
706 	struct se_device *dev = cmd->se_dev;
707 	int success = scsi_status == GOOD;
708 	unsigned long flags;
709 
710 	cmd->scsi_status = scsi_status;
711 
712 
713 	spin_lock_irqsave(&cmd->t_state_lock, flags);
714 
715 	if (dev && dev->transport->transport_complete) {
716 		dev->transport->transport_complete(cmd,
717 				cmd->t_data_sg,
718 				transport_get_sense_buffer(cmd));
719 		if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE)
720 			success = 1;
721 	}
722 
723 	/*
724 	 * Check for case where an explicit ABORT_TASK has been received
725 	 * and transport_wait_for_tasks() will be waiting for completion..
726 	 */
727 	if (cmd->transport_state & CMD_T_ABORTED ||
728 	    cmd->transport_state & CMD_T_STOP) {
729 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
730 		complete_all(&cmd->t_transport_stop_comp);
731 		return;
732 	} else if (!success) {
733 		INIT_WORK(&cmd->work, target_complete_failure_work);
734 	} else {
735 		INIT_WORK(&cmd->work, target_complete_ok_work);
736 	}
737 
738 	cmd->t_state = TRANSPORT_COMPLETE;
739 	cmd->transport_state |= (CMD_T_COMPLETE | CMD_T_ACTIVE);
740 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
741 
742 	if (cmd->se_cmd_flags & SCF_USE_CPUID)
743 		queue_work_on(cmd->cpuid, target_completion_wq, &cmd->work);
744 	else
745 		queue_work(target_completion_wq, &cmd->work);
746 }
747 EXPORT_SYMBOL(target_complete_cmd);
748 
749 void target_complete_cmd_with_length(struct se_cmd *cmd, u8 scsi_status, int length)
750 {
751 	if (scsi_status == SAM_STAT_GOOD && length < cmd->data_length) {
752 		if (cmd->se_cmd_flags & SCF_UNDERFLOW_BIT) {
753 			cmd->residual_count += cmd->data_length - length;
754 		} else {
755 			cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
756 			cmd->residual_count = cmd->data_length - length;
757 		}
758 
759 		cmd->data_length = length;
760 	}
761 
762 	target_complete_cmd(cmd, scsi_status);
763 }
764 EXPORT_SYMBOL(target_complete_cmd_with_length);
765 
766 static void target_add_to_state_list(struct se_cmd *cmd)
767 {
768 	struct se_device *dev = cmd->se_dev;
769 	unsigned long flags;
770 
771 	spin_lock_irqsave(&dev->execute_task_lock, flags);
772 	if (!cmd->state_active) {
773 		list_add_tail(&cmd->state_list, &dev->state_list);
774 		cmd->state_active = true;
775 	}
776 	spin_unlock_irqrestore(&dev->execute_task_lock, flags);
777 }
778 
779 /*
780  * Handle QUEUE_FULL / -EAGAIN and -ENOMEM status
781  */
782 static void transport_write_pending_qf(struct se_cmd *cmd);
783 static void transport_complete_qf(struct se_cmd *cmd);
784 
785 void target_qf_do_work(struct work_struct *work)
786 {
787 	struct se_device *dev = container_of(work, struct se_device,
788 					qf_work_queue);
789 	LIST_HEAD(qf_cmd_list);
790 	struct se_cmd *cmd, *cmd_tmp;
791 
792 	spin_lock_irq(&dev->qf_cmd_lock);
793 	list_splice_init(&dev->qf_cmd_list, &qf_cmd_list);
794 	spin_unlock_irq(&dev->qf_cmd_lock);
795 
796 	list_for_each_entry_safe(cmd, cmd_tmp, &qf_cmd_list, se_qf_node) {
797 		list_del(&cmd->se_qf_node);
798 		atomic_dec_mb(&dev->dev_qf_count);
799 
800 		pr_debug("Processing %s cmd: %p QUEUE_FULL in work queue"
801 			" context: %s\n", cmd->se_tfo->get_fabric_name(), cmd,
802 			(cmd->t_state == TRANSPORT_COMPLETE_QF_OK) ? "COMPLETE_OK" :
803 			(cmd->t_state == TRANSPORT_COMPLETE_QF_WP) ? "WRITE_PENDING"
804 			: "UNKNOWN");
805 
806 		if (cmd->t_state == TRANSPORT_COMPLETE_QF_WP)
807 			transport_write_pending_qf(cmd);
808 		else if (cmd->t_state == TRANSPORT_COMPLETE_QF_OK ||
809 			 cmd->t_state == TRANSPORT_COMPLETE_QF_ERR)
810 			transport_complete_qf(cmd);
811 	}
812 }
813 
814 unsigned char *transport_dump_cmd_direction(struct se_cmd *cmd)
815 {
816 	switch (cmd->data_direction) {
817 	case DMA_NONE:
818 		return "NONE";
819 	case DMA_FROM_DEVICE:
820 		return "READ";
821 	case DMA_TO_DEVICE:
822 		return "WRITE";
823 	case DMA_BIDIRECTIONAL:
824 		return "BIDI";
825 	default:
826 		break;
827 	}
828 
829 	return "UNKNOWN";
830 }
831 
832 void transport_dump_dev_state(
833 	struct se_device *dev,
834 	char *b,
835 	int *bl)
836 {
837 	*bl += sprintf(b + *bl, "Status: ");
838 	if (dev->export_count)
839 		*bl += sprintf(b + *bl, "ACTIVATED");
840 	else
841 		*bl += sprintf(b + *bl, "DEACTIVATED");
842 
843 	*bl += sprintf(b + *bl, "  Max Queue Depth: %d", dev->queue_depth);
844 	*bl += sprintf(b + *bl, "  SectorSize: %u  HwMaxSectors: %u\n",
845 		dev->dev_attrib.block_size,
846 		dev->dev_attrib.hw_max_sectors);
847 	*bl += sprintf(b + *bl, "        ");
848 }
849 
850 void transport_dump_vpd_proto_id(
851 	struct t10_vpd *vpd,
852 	unsigned char *p_buf,
853 	int p_buf_len)
854 {
855 	unsigned char buf[VPD_TMP_BUF_SIZE];
856 	int len;
857 
858 	memset(buf, 0, VPD_TMP_BUF_SIZE);
859 	len = sprintf(buf, "T10 VPD Protocol Identifier: ");
860 
861 	switch (vpd->protocol_identifier) {
862 	case 0x00:
863 		sprintf(buf+len, "Fibre Channel\n");
864 		break;
865 	case 0x10:
866 		sprintf(buf+len, "Parallel SCSI\n");
867 		break;
868 	case 0x20:
869 		sprintf(buf+len, "SSA\n");
870 		break;
871 	case 0x30:
872 		sprintf(buf+len, "IEEE 1394\n");
873 		break;
874 	case 0x40:
875 		sprintf(buf+len, "SCSI Remote Direct Memory Access"
876 				" Protocol\n");
877 		break;
878 	case 0x50:
879 		sprintf(buf+len, "Internet SCSI (iSCSI)\n");
880 		break;
881 	case 0x60:
882 		sprintf(buf+len, "SAS Serial SCSI Protocol\n");
883 		break;
884 	case 0x70:
885 		sprintf(buf+len, "Automation/Drive Interface Transport"
886 				" Protocol\n");
887 		break;
888 	case 0x80:
889 		sprintf(buf+len, "AT Attachment Interface ATA/ATAPI\n");
890 		break;
891 	default:
892 		sprintf(buf+len, "Unknown 0x%02x\n",
893 				vpd->protocol_identifier);
894 		break;
895 	}
896 
897 	if (p_buf)
898 		strncpy(p_buf, buf, p_buf_len);
899 	else
900 		pr_debug("%s", buf);
901 }
902 
903 void
904 transport_set_vpd_proto_id(struct t10_vpd *vpd, unsigned char *page_83)
905 {
906 	/*
907 	 * Check if the Protocol Identifier Valid (PIV) bit is set..
908 	 *
909 	 * from spc3r23.pdf section 7.5.1
910 	 */
911 	 if (page_83[1] & 0x80) {
912 		vpd->protocol_identifier = (page_83[0] & 0xf0);
913 		vpd->protocol_identifier_set = 1;
914 		transport_dump_vpd_proto_id(vpd, NULL, 0);
915 	}
916 }
917 EXPORT_SYMBOL(transport_set_vpd_proto_id);
918 
919 int transport_dump_vpd_assoc(
920 	struct t10_vpd *vpd,
921 	unsigned char *p_buf,
922 	int p_buf_len)
923 {
924 	unsigned char buf[VPD_TMP_BUF_SIZE];
925 	int ret = 0;
926 	int len;
927 
928 	memset(buf, 0, VPD_TMP_BUF_SIZE);
929 	len = sprintf(buf, "T10 VPD Identifier Association: ");
930 
931 	switch (vpd->association) {
932 	case 0x00:
933 		sprintf(buf+len, "addressed logical unit\n");
934 		break;
935 	case 0x10:
936 		sprintf(buf+len, "target port\n");
937 		break;
938 	case 0x20:
939 		sprintf(buf+len, "SCSI target device\n");
940 		break;
941 	default:
942 		sprintf(buf+len, "Unknown 0x%02x\n", vpd->association);
943 		ret = -EINVAL;
944 		break;
945 	}
946 
947 	if (p_buf)
948 		strncpy(p_buf, buf, p_buf_len);
949 	else
950 		pr_debug("%s", buf);
951 
952 	return ret;
953 }
954 
955 int transport_set_vpd_assoc(struct t10_vpd *vpd, unsigned char *page_83)
956 {
957 	/*
958 	 * The VPD identification association..
959 	 *
960 	 * from spc3r23.pdf Section 7.6.3.1 Table 297
961 	 */
962 	vpd->association = (page_83[1] & 0x30);
963 	return transport_dump_vpd_assoc(vpd, NULL, 0);
964 }
965 EXPORT_SYMBOL(transport_set_vpd_assoc);
966 
967 int transport_dump_vpd_ident_type(
968 	struct t10_vpd *vpd,
969 	unsigned char *p_buf,
970 	int p_buf_len)
971 {
972 	unsigned char buf[VPD_TMP_BUF_SIZE];
973 	int ret = 0;
974 	int len;
975 
976 	memset(buf, 0, VPD_TMP_BUF_SIZE);
977 	len = sprintf(buf, "T10 VPD Identifier Type: ");
978 
979 	switch (vpd->device_identifier_type) {
980 	case 0x00:
981 		sprintf(buf+len, "Vendor specific\n");
982 		break;
983 	case 0x01:
984 		sprintf(buf+len, "T10 Vendor ID based\n");
985 		break;
986 	case 0x02:
987 		sprintf(buf+len, "EUI-64 based\n");
988 		break;
989 	case 0x03:
990 		sprintf(buf+len, "NAA\n");
991 		break;
992 	case 0x04:
993 		sprintf(buf+len, "Relative target port identifier\n");
994 		break;
995 	case 0x08:
996 		sprintf(buf+len, "SCSI name string\n");
997 		break;
998 	default:
999 		sprintf(buf+len, "Unsupported: 0x%02x\n",
1000 				vpd->device_identifier_type);
1001 		ret = -EINVAL;
1002 		break;
1003 	}
1004 
1005 	if (p_buf) {
1006 		if (p_buf_len < strlen(buf)+1)
1007 			return -EINVAL;
1008 		strncpy(p_buf, buf, p_buf_len);
1009 	} else {
1010 		pr_debug("%s", buf);
1011 	}
1012 
1013 	return ret;
1014 }
1015 
1016 int transport_set_vpd_ident_type(struct t10_vpd *vpd, unsigned char *page_83)
1017 {
1018 	/*
1019 	 * The VPD identifier type..
1020 	 *
1021 	 * from spc3r23.pdf Section 7.6.3.1 Table 298
1022 	 */
1023 	vpd->device_identifier_type = (page_83[1] & 0x0f);
1024 	return transport_dump_vpd_ident_type(vpd, NULL, 0);
1025 }
1026 EXPORT_SYMBOL(transport_set_vpd_ident_type);
1027 
1028 int transport_dump_vpd_ident(
1029 	struct t10_vpd *vpd,
1030 	unsigned char *p_buf,
1031 	int p_buf_len)
1032 {
1033 	unsigned char buf[VPD_TMP_BUF_SIZE];
1034 	int ret = 0;
1035 
1036 	memset(buf, 0, VPD_TMP_BUF_SIZE);
1037 
1038 	switch (vpd->device_identifier_code_set) {
1039 	case 0x01: /* Binary */
1040 		snprintf(buf, sizeof(buf),
1041 			"T10 VPD Binary Device Identifier: %s\n",
1042 			&vpd->device_identifier[0]);
1043 		break;
1044 	case 0x02: /* ASCII */
1045 		snprintf(buf, sizeof(buf),
1046 			"T10 VPD ASCII Device Identifier: %s\n",
1047 			&vpd->device_identifier[0]);
1048 		break;
1049 	case 0x03: /* UTF-8 */
1050 		snprintf(buf, sizeof(buf),
1051 			"T10 VPD UTF-8 Device Identifier: %s\n",
1052 			&vpd->device_identifier[0]);
1053 		break;
1054 	default:
1055 		sprintf(buf, "T10 VPD Device Identifier encoding unsupported:"
1056 			" 0x%02x", vpd->device_identifier_code_set);
1057 		ret = -EINVAL;
1058 		break;
1059 	}
1060 
1061 	if (p_buf)
1062 		strncpy(p_buf, buf, p_buf_len);
1063 	else
1064 		pr_debug("%s", buf);
1065 
1066 	return ret;
1067 }
1068 
1069 int
1070 transport_set_vpd_ident(struct t10_vpd *vpd, unsigned char *page_83)
1071 {
1072 	static const char hex_str[] = "0123456789abcdef";
1073 	int j = 0, i = 4; /* offset to start of the identifier */
1074 
1075 	/*
1076 	 * The VPD Code Set (encoding)
1077 	 *
1078 	 * from spc3r23.pdf Section 7.6.3.1 Table 296
1079 	 */
1080 	vpd->device_identifier_code_set = (page_83[0] & 0x0f);
1081 	switch (vpd->device_identifier_code_set) {
1082 	case 0x01: /* Binary */
1083 		vpd->device_identifier[j++] =
1084 				hex_str[vpd->device_identifier_type];
1085 		while (i < (4 + page_83[3])) {
1086 			vpd->device_identifier[j++] =
1087 				hex_str[(page_83[i] & 0xf0) >> 4];
1088 			vpd->device_identifier[j++] =
1089 				hex_str[page_83[i] & 0x0f];
1090 			i++;
1091 		}
1092 		break;
1093 	case 0x02: /* ASCII */
1094 	case 0x03: /* UTF-8 */
1095 		while (i < (4 + page_83[3]))
1096 			vpd->device_identifier[j++] = page_83[i++];
1097 		break;
1098 	default:
1099 		break;
1100 	}
1101 
1102 	return transport_dump_vpd_ident(vpd, NULL, 0);
1103 }
1104 EXPORT_SYMBOL(transport_set_vpd_ident);
1105 
1106 static sense_reason_t
1107 target_check_max_data_sg_nents(struct se_cmd *cmd, struct se_device *dev,
1108 			       unsigned int size)
1109 {
1110 	u32 mtl;
1111 
1112 	if (!cmd->se_tfo->max_data_sg_nents)
1113 		return TCM_NO_SENSE;
1114 	/*
1115 	 * Check if fabric enforced maximum SGL entries per I/O descriptor
1116 	 * exceeds se_cmd->data_length.  If true, set SCF_UNDERFLOW_BIT +
1117 	 * residual_count and reduce original cmd->data_length to maximum
1118 	 * length based on single PAGE_SIZE entry scatter-lists.
1119 	 */
1120 	mtl = (cmd->se_tfo->max_data_sg_nents * PAGE_SIZE);
1121 	if (cmd->data_length > mtl) {
1122 		/*
1123 		 * If an existing CDB overflow is present, calculate new residual
1124 		 * based on CDB size minus fabric maximum transfer length.
1125 		 *
1126 		 * If an existing CDB underflow is present, calculate new residual
1127 		 * based on original cmd->data_length minus fabric maximum transfer
1128 		 * length.
1129 		 *
1130 		 * Otherwise, set the underflow residual based on cmd->data_length
1131 		 * minus fabric maximum transfer length.
1132 		 */
1133 		if (cmd->se_cmd_flags & SCF_OVERFLOW_BIT) {
1134 			cmd->residual_count = (size - mtl);
1135 		} else if (cmd->se_cmd_flags & SCF_UNDERFLOW_BIT) {
1136 			u32 orig_dl = size + cmd->residual_count;
1137 			cmd->residual_count = (orig_dl - mtl);
1138 		} else {
1139 			cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
1140 			cmd->residual_count = (cmd->data_length - mtl);
1141 		}
1142 		cmd->data_length = mtl;
1143 		/*
1144 		 * Reset sbc_check_prot() calculated protection payload
1145 		 * length based upon the new smaller MTL.
1146 		 */
1147 		if (cmd->prot_length) {
1148 			u32 sectors = (mtl / dev->dev_attrib.block_size);
1149 			cmd->prot_length = dev->prot_length * sectors;
1150 		}
1151 	}
1152 	return TCM_NO_SENSE;
1153 }
1154 
1155 sense_reason_t
1156 target_cmd_size_check(struct se_cmd *cmd, unsigned int size)
1157 {
1158 	struct se_device *dev = cmd->se_dev;
1159 
1160 	if (cmd->unknown_data_length) {
1161 		cmd->data_length = size;
1162 	} else if (size != cmd->data_length) {
1163 		pr_warn("TARGET_CORE[%s]: Expected Transfer Length:"
1164 			" %u does not match SCSI CDB Length: %u for SAM Opcode:"
1165 			" 0x%02x\n", cmd->se_tfo->get_fabric_name(),
1166 				cmd->data_length, size, cmd->t_task_cdb[0]);
1167 
1168 		if (cmd->data_direction == DMA_TO_DEVICE &&
1169 		    cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) {
1170 			pr_err("Rejecting underflow/overflow WRITE data\n");
1171 			return TCM_INVALID_CDB_FIELD;
1172 		}
1173 		/*
1174 		 * Reject READ_* or WRITE_* with overflow/underflow for
1175 		 * type SCF_SCSI_DATA_CDB.
1176 		 */
1177 		if (dev->dev_attrib.block_size != 512)  {
1178 			pr_err("Failing OVERFLOW/UNDERFLOW for LBA op"
1179 				" CDB on non 512-byte sector setup subsystem"
1180 				" plugin: %s\n", dev->transport->name);
1181 			/* Returns CHECK_CONDITION + INVALID_CDB_FIELD */
1182 			return TCM_INVALID_CDB_FIELD;
1183 		}
1184 		/*
1185 		 * For the overflow case keep the existing fabric provided
1186 		 * ->data_length.  Otherwise for the underflow case, reset
1187 		 * ->data_length to the smaller SCSI expected data transfer
1188 		 * length.
1189 		 */
1190 		if (size > cmd->data_length) {
1191 			cmd->se_cmd_flags |= SCF_OVERFLOW_BIT;
1192 			cmd->residual_count = (size - cmd->data_length);
1193 		} else {
1194 			cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
1195 			cmd->residual_count = (cmd->data_length - size);
1196 			cmd->data_length = size;
1197 		}
1198 	}
1199 
1200 	return target_check_max_data_sg_nents(cmd, dev, size);
1201 
1202 }
1203 
1204 /*
1205  * Used by fabric modules containing a local struct se_cmd within their
1206  * fabric dependent per I/O descriptor.
1207  *
1208  * Preserves the value of @cmd->tag.
1209  */
1210 void transport_init_se_cmd(
1211 	struct se_cmd *cmd,
1212 	const struct target_core_fabric_ops *tfo,
1213 	struct se_session *se_sess,
1214 	u32 data_length,
1215 	int data_direction,
1216 	int task_attr,
1217 	unsigned char *sense_buffer)
1218 {
1219 	INIT_LIST_HEAD(&cmd->se_delayed_node);
1220 	INIT_LIST_HEAD(&cmd->se_qf_node);
1221 	INIT_LIST_HEAD(&cmd->se_cmd_list);
1222 	INIT_LIST_HEAD(&cmd->state_list);
1223 	init_completion(&cmd->t_transport_stop_comp);
1224 	init_completion(&cmd->cmd_wait_comp);
1225 	spin_lock_init(&cmd->t_state_lock);
1226 	kref_init(&cmd->cmd_kref);
1227 
1228 	cmd->se_tfo = tfo;
1229 	cmd->se_sess = se_sess;
1230 	cmd->data_length = data_length;
1231 	cmd->data_direction = data_direction;
1232 	cmd->sam_task_attr = task_attr;
1233 	cmd->sense_buffer = sense_buffer;
1234 
1235 	cmd->state_active = false;
1236 }
1237 EXPORT_SYMBOL(transport_init_se_cmd);
1238 
1239 static sense_reason_t
1240 transport_check_alloc_task_attr(struct se_cmd *cmd)
1241 {
1242 	struct se_device *dev = cmd->se_dev;
1243 
1244 	/*
1245 	 * Check if SAM Task Attribute emulation is enabled for this
1246 	 * struct se_device storage object
1247 	 */
1248 	if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
1249 		return 0;
1250 
1251 	if (cmd->sam_task_attr == TCM_ACA_TAG) {
1252 		pr_debug("SAM Task Attribute ACA"
1253 			" emulation is not supported\n");
1254 		return TCM_INVALID_CDB_FIELD;
1255 	}
1256 
1257 	return 0;
1258 }
1259 
1260 sense_reason_t
1261 target_setup_cmd_from_cdb(struct se_cmd *cmd, unsigned char *cdb)
1262 {
1263 	struct se_device *dev = cmd->se_dev;
1264 	sense_reason_t ret;
1265 
1266 	/*
1267 	 * Ensure that the received CDB is less than the max (252 + 8) bytes
1268 	 * for VARIABLE_LENGTH_CMD
1269 	 */
1270 	if (scsi_command_size(cdb) > SCSI_MAX_VARLEN_CDB_SIZE) {
1271 		pr_err("Received SCSI CDB with command_size: %d that"
1272 			" exceeds SCSI_MAX_VARLEN_CDB_SIZE: %d\n",
1273 			scsi_command_size(cdb), SCSI_MAX_VARLEN_CDB_SIZE);
1274 		return TCM_INVALID_CDB_FIELD;
1275 	}
1276 	/*
1277 	 * If the received CDB is larger than TCM_MAX_COMMAND_SIZE,
1278 	 * allocate the additional extended CDB buffer now..  Otherwise
1279 	 * setup the pointer from __t_task_cdb to t_task_cdb.
1280 	 */
1281 	if (scsi_command_size(cdb) > sizeof(cmd->__t_task_cdb)) {
1282 		cmd->t_task_cdb = kzalloc(scsi_command_size(cdb),
1283 						GFP_KERNEL);
1284 		if (!cmd->t_task_cdb) {
1285 			pr_err("Unable to allocate cmd->t_task_cdb"
1286 				" %u > sizeof(cmd->__t_task_cdb): %lu ops\n",
1287 				scsi_command_size(cdb),
1288 				(unsigned long)sizeof(cmd->__t_task_cdb));
1289 			return TCM_OUT_OF_RESOURCES;
1290 		}
1291 	} else
1292 		cmd->t_task_cdb = &cmd->__t_task_cdb[0];
1293 	/*
1294 	 * Copy the original CDB into cmd->
1295 	 */
1296 	memcpy(cmd->t_task_cdb, cdb, scsi_command_size(cdb));
1297 
1298 	trace_target_sequencer_start(cmd);
1299 
1300 	ret = dev->transport->parse_cdb(cmd);
1301 	if (ret == TCM_UNSUPPORTED_SCSI_OPCODE)
1302 		pr_warn_ratelimited("%s/%s: Unsupported SCSI Opcode 0x%02x, sending CHECK_CONDITION.\n",
1303 				    cmd->se_tfo->get_fabric_name(),
1304 				    cmd->se_sess->se_node_acl->initiatorname,
1305 				    cmd->t_task_cdb[0]);
1306 	if (ret)
1307 		return ret;
1308 
1309 	ret = transport_check_alloc_task_attr(cmd);
1310 	if (ret)
1311 		return ret;
1312 
1313 	cmd->se_cmd_flags |= SCF_SUPPORTED_SAM_OPCODE;
1314 	atomic_long_inc(&cmd->se_lun->lun_stats.cmd_pdus);
1315 	return 0;
1316 }
1317 EXPORT_SYMBOL(target_setup_cmd_from_cdb);
1318 
1319 /*
1320  * Used by fabric module frontends to queue tasks directly.
1321  * May only be used from process context.
1322  */
1323 int transport_handle_cdb_direct(
1324 	struct se_cmd *cmd)
1325 {
1326 	sense_reason_t ret;
1327 
1328 	if (!cmd->se_lun) {
1329 		dump_stack();
1330 		pr_err("cmd->se_lun is NULL\n");
1331 		return -EINVAL;
1332 	}
1333 	if (in_interrupt()) {
1334 		dump_stack();
1335 		pr_err("transport_generic_handle_cdb cannot be called"
1336 				" from interrupt context\n");
1337 		return -EINVAL;
1338 	}
1339 	/*
1340 	 * Set TRANSPORT_NEW_CMD state and CMD_T_ACTIVE to ensure that
1341 	 * outstanding descriptors are handled correctly during shutdown via
1342 	 * transport_wait_for_tasks()
1343 	 *
1344 	 * Also, we don't take cmd->t_state_lock here as we only expect
1345 	 * this to be called for initial descriptor submission.
1346 	 */
1347 	cmd->t_state = TRANSPORT_NEW_CMD;
1348 	cmd->transport_state |= CMD_T_ACTIVE;
1349 
1350 	/*
1351 	 * transport_generic_new_cmd() is already handling QUEUE_FULL,
1352 	 * so follow TRANSPORT_NEW_CMD processing thread context usage
1353 	 * and call transport_generic_request_failure() if necessary..
1354 	 */
1355 	ret = transport_generic_new_cmd(cmd);
1356 	if (ret)
1357 		transport_generic_request_failure(cmd, ret);
1358 	return 0;
1359 }
1360 EXPORT_SYMBOL(transport_handle_cdb_direct);
1361 
1362 sense_reason_t
1363 transport_generic_map_mem_to_cmd(struct se_cmd *cmd, struct scatterlist *sgl,
1364 		u32 sgl_count, struct scatterlist *sgl_bidi, u32 sgl_bidi_count)
1365 {
1366 	if (!sgl || !sgl_count)
1367 		return 0;
1368 
1369 	/*
1370 	 * Reject SCSI data overflow with map_mem_to_cmd() as incoming
1371 	 * scatterlists already have been set to follow what the fabric
1372 	 * passes for the original expected data transfer length.
1373 	 */
1374 	if (cmd->se_cmd_flags & SCF_OVERFLOW_BIT) {
1375 		pr_warn("Rejecting SCSI DATA overflow for fabric using"
1376 			" SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC\n");
1377 		return TCM_INVALID_CDB_FIELD;
1378 	}
1379 
1380 	cmd->t_data_sg = sgl;
1381 	cmd->t_data_nents = sgl_count;
1382 	cmd->t_bidi_data_sg = sgl_bidi;
1383 	cmd->t_bidi_data_nents = sgl_bidi_count;
1384 
1385 	cmd->se_cmd_flags |= SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC;
1386 	return 0;
1387 }
1388 
1389 /*
1390  * target_submit_cmd_map_sgls - lookup unpacked lun and submit uninitialized
1391  * 			 se_cmd + use pre-allocated SGL memory.
1392  *
1393  * @se_cmd: command descriptor to submit
1394  * @se_sess: associated se_sess for endpoint
1395  * @cdb: pointer to SCSI CDB
1396  * @sense: pointer to SCSI sense buffer
1397  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1398  * @data_length: fabric expected data transfer length
1399  * @task_addr: SAM task attribute
1400  * @data_dir: DMA data direction
1401  * @flags: flags for command submission from target_sc_flags_tables
1402  * @sgl: struct scatterlist memory for unidirectional mapping
1403  * @sgl_count: scatterlist count for unidirectional mapping
1404  * @sgl_bidi: struct scatterlist memory for bidirectional READ mapping
1405  * @sgl_bidi_count: scatterlist count for bidirectional READ mapping
1406  * @sgl_prot: struct scatterlist memory protection information
1407  * @sgl_prot_count: scatterlist count for protection information
1408  *
1409  * Task tags are supported if the caller has set @se_cmd->tag.
1410  *
1411  * Returns non zero to signal active I/O shutdown failure.  All other
1412  * setup exceptions will be returned as a SCSI CHECK_CONDITION response,
1413  * but still return zero here.
1414  *
1415  * This may only be called from process context, and also currently
1416  * assumes internal allocation of fabric payload buffer by target-core.
1417  */
1418 int target_submit_cmd_map_sgls(struct se_cmd *se_cmd, struct se_session *se_sess,
1419 		unsigned char *cdb, unsigned char *sense, u64 unpacked_lun,
1420 		u32 data_length, int task_attr, int data_dir, int flags,
1421 		struct scatterlist *sgl, u32 sgl_count,
1422 		struct scatterlist *sgl_bidi, u32 sgl_bidi_count,
1423 		struct scatterlist *sgl_prot, u32 sgl_prot_count)
1424 {
1425 	struct se_portal_group *se_tpg;
1426 	sense_reason_t rc;
1427 	int ret;
1428 
1429 	se_tpg = se_sess->se_tpg;
1430 	BUG_ON(!se_tpg);
1431 	BUG_ON(se_cmd->se_tfo || se_cmd->se_sess);
1432 	BUG_ON(in_interrupt());
1433 	/*
1434 	 * Initialize se_cmd for target operation.  From this point
1435 	 * exceptions are handled by sending exception status via
1436 	 * target_core_fabric_ops->queue_status() callback
1437 	 */
1438 	transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess,
1439 				data_length, data_dir, task_attr, sense);
1440 
1441 	if (flags & TARGET_SCF_USE_CPUID)
1442 		se_cmd->se_cmd_flags |= SCF_USE_CPUID;
1443 	else
1444 		se_cmd->cpuid = WORK_CPU_UNBOUND;
1445 
1446 	if (flags & TARGET_SCF_UNKNOWN_SIZE)
1447 		se_cmd->unknown_data_length = 1;
1448 	/*
1449 	 * Obtain struct se_cmd->cmd_kref reference and add new cmd to
1450 	 * se_sess->sess_cmd_list.  A second kref_get here is necessary
1451 	 * for fabrics using TARGET_SCF_ACK_KREF that expect a second
1452 	 * kref_put() to happen during fabric packet acknowledgement.
1453 	 */
1454 	ret = target_get_sess_cmd(se_cmd, flags & TARGET_SCF_ACK_KREF);
1455 	if (ret)
1456 		return ret;
1457 	/*
1458 	 * Signal bidirectional data payloads to target-core
1459 	 */
1460 	if (flags & TARGET_SCF_BIDI_OP)
1461 		se_cmd->se_cmd_flags |= SCF_BIDI;
1462 	/*
1463 	 * Locate se_lun pointer and attach it to struct se_cmd
1464 	 */
1465 	rc = transport_lookup_cmd_lun(se_cmd, unpacked_lun);
1466 	if (rc) {
1467 		transport_send_check_condition_and_sense(se_cmd, rc, 0);
1468 		target_put_sess_cmd(se_cmd);
1469 		return 0;
1470 	}
1471 
1472 	rc = target_setup_cmd_from_cdb(se_cmd, cdb);
1473 	if (rc != 0) {
1474 		transport_generic_request_failure(se_cmd, rc);
1475 		return 0;
1476 	}
1477 
1478 	/*
1479 	 * Save pointers for SGLs containing protection information,
1480 	 * if present.
1481 	 */
1482 	if (sgl_prot_count) {
1483 		se_cmd->t_prot_sg = sgl_prot;
1484 		se_cmd->t_prot_nents = sgl_prot_count;
1485 		se_cmd->se_cmd_flags |= SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC;
1486 	}
1487 
1488 	/*
1489 	 * When a non zero sgl_count has been passed perform SGL passthrough
1490 	 * mapping for pre-allocated fabric memory instead of having target
1491 	 * core perform an internal SGL allocation..
1492 	 */
1493 	if (sgl_count != 0) {
1494 		BUG_ON(!sgl);
1495 
1496 		/*
1497 		 * A work-around for tcm_loop as some userspace code via
1498 		 * scsi-generic do not memset their associated read buffers,
1499 		 * so go ahead and do that here for type non-data CDBs.  Also
1500 		 * note that this is currently guaranteed to be a single SGL
1501 		 * for this case by target core in target_setup_cmd_from_cdb()
1502 		 * -> transport_generic_cmd_sequencer().
1503 		 */
1504 		if (!(se_cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) &&
1505 		     se_cmd->data_direction == DMA_FROM_DEVICE) {
1506 			unsigned char *buf = NULL;
1507 
1508 			if (sgl)
1509 				buf = kmap(sg_page(sgl)) + sgl->offset;
1510 
1511 			if (buf) {
1512 				memset(buf, 0, sgl->length);
1513 				kunmap(sg_page(sgl));
1514 			}
1515 		}
1516 
1517 		rc = transport_generic_map_mem_to_cmd(se_cmd, sgl, sgl_count,
1518 				sgl_bidi, sgl_bidi_count);
1519 		if (rc != 0) {
1520 			transport_generic_request_failure(se_cmd, rc);
1521 			return 0;
1522 		}
1523 	}
1524 
1525 	/*
1526 	 * Check if we need to delay processing because of ALUA
1527 	 * Active/NonOptimized primary access state..
1528 	 */
1529 	core_alua_check_nonop_delay(se_cmd);
1530 
1531 	transport_handle_cdb_direct(se_cmd);
1532 	return 0;
1533 }
1534 EXPORT_SYMBOL(target_submit_cmd_map_sgls);
1535 
1536 /*
1537  * target_submit_cmd - lookup unpacked lun and submit uninitialized se_cmd
1538  *
1539  * @se_cmd: command descriptor to submit
1540  * @se_sess: associated se_sess for endpoint
1541  * @cdb: pointer to SCSI CDB
1542  * @sense: pointer to SCSI sense buffer
1543  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1544  * @data_length: fabric expected data transfer length
1545  * @task_addr: SAM task attribute
1546  * @data_dir: DMA data direction
1547  * @flags: flags for command submission from target_sc_flags_tables
1548  *
1549  * Task tags are supported if the caller has set @se_cmd->tag.
1550  *
1551  * Returns non zero to signal active I/O shutdown failure.  All other
1552  * setup exceptions will be returned as a SCSI CHECK_CONDITION response,
1553  * but still return zero here.
1554  *
1555  * This may only be called from process context, and also currently
1556  * assumes internal allocation of fabric payload buffer by target-core.
1557  *
1558  * It also assumes interal target core SGL memory allocation.
1559  */
1560 int target_submit_cmd(struct se_cmd *se_cmd, struct se_session *se_sess,
1561 		unsigned char *cdb, unsigned char *sense, u64 unpacked_lun,
1562 		u32 data_length, int task_attr, int data_dir, int flags)
1563 {
1564 	return target_submit_cmd_map_sgls(se_cmd, se_sess, cdb, sense,
1565 			unpacked_lun, data_length, task_attr, data_dir,
1566 			flags, NULL, 0, NULL, 0, NULL, 0);
1567 }
1568 EXPORT_SYMBOL(target_submit_cmd);
1569 
1570 static void target_complete_tmr_failure(struct work_struct *work)
1571 {
1572 	struct se_cmd *se_cmd = container_of(work, struct se_cmd, work);
1573 
1574 	se_cmd->se_tmr_req->response = TMR_LUN_DOES_NOT_EXIST;
1575 	se_cmd->se_tfo->queue_tm_rsp(se_cmd);
1576 
1577 	transport_cmd_check_stop_to_fabric(se_cmd);
1578 }
1579 
1580 /**
1581  * target_submit_tmr - lookup unpacked lun and submit uninitialized se_cmd
1582  *                     for TMR CDBs
1583  *
1584  * @se_cmd: command descriptor to submit
1585  * @se_sess: associated se_sess for endpoint
1586  * @sense: pointer to SCSI sense buffer
1587  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1588  * @fabric_context: fabric context for TMR req
1589  * @tm_type: Type of TM request
1590  * @gfp: gfp type for caller
1591  * @tag: referenced task tag for TMR_ABORT_TASK
1592  * @flags: submit cmd flags
1593  *
1594  * Callable from all contexts.
1595  **/
1596 
1597 int target_submit_tmr(struct se_cmd *se_cmd, struct se_session *se_sess,
1598 		unsigned char *sense, u64 unpacked_lun,
1599 		void *fabric_tmr_ptr, unsigned char tm_type,
1600 		gfp_t gfp, u64 tag, int flags)
1601 {
1602 	struct se_portal_group *se_tpg;
1603 	int ret;
1604 
1605 	se_tpg = se_sess->se_tpg;
1606 	BUG_ON(!se_tpg);
1607 
1608 	transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess,
1609 			      0, DMA_NONE, TCM_SIMPLE_TAG, sense);
1610 	/*
1611 	 * FIXME: Currently expect caller to handle se_cmd->se_tmr_req
1612 	 * allocation failure.
1613 	 */
1614 	ret = core_tmr_alloc_req(se_cmd, fabric_tmr_ptr, tm_type, gfp);
1615 	if (ret < 0)
1616 		return -ENOMEM;
1617 
1618 	if (tm_type == TMR_ABORT_TASK)
1619 		se_cmd->se_tmr_req->ref_task_tag = tag;
1620 
1621 	/* See target_submit_cmd for commentary */
1622 	ret = target_get_sess_cmd(se_cmd, flags & TARGET_SCF_ACK_KREF);
1623 	if (ret) {
1624 		core_tmr_release_req(se_cmd->se_tmr_req);
1625 		return ret;
1626 	}
1627 
1628 	ret = transport_lookup_tmr_lun(se_cmd, unpacked_lun);
1629 	if (ret) {
1630 		/*
1631 		 * For callback during failure handling, push this work off
1632 		 * to process context with TMR_LUN_DOES_NOT_EXIST status.
1633 		 */
1634 		INIT_WORK(&se_cmd->work, target_complete_tmr_failure);
1635 		schedule_work(&se_cmd->work);
1636 		return 0;
1637 	}
1638 	transport_generic_handle_tmr(se_cmd);
1639 	return 0;
1640 }
1641 EXPORT_SYMBOL(target_submit_tmr);
1642 
1643 /*
1644  * Handle SAM-esque emulation for generic transport request failures.
1645  */
1646 void transport_generic_request_failure(struct se_cmd *cmd,
1647 		sense_reason_t sense_reason)
1648 {
1649 	int ret = 0, post_ret = 0;
1650 
1651 	if (transport_check_aborted_status(cmd, 1))
1652 		return;
1653 
1654 	pr_debug("-----[ Storage Engine Exception for cmd: %p ITT: 0x%08llx"
1655 		" CDB: 0x%02x\n", cmd, cmd->tag, cmd->t_task_cdb[0]);
1656 	pr_debug("-----[ i_state: %d t_state: %d sense_reason: %d\n",
1657 		cmd->se_tfo->get_cmd_state(cmd),
1658 		cmd->t_state, sense_reason);
1659 	pr_debug("-----[ CMD_T_ACTIVE: %d CMD_T_STOP: %d CMD_T_SENT: %d\n",
1660 		(cmd->transport_state & CMD_T_ACTIVE) != 0,
1661 		(cmd->transport_state & CMD_T_STOP) != 0,
1662 		(cmd->transport_state & CMD_T_SENT) != 0);
1663 
1664 	/*
1665 	 * For SAM Task Attribute emulation for failed struct se_cmd
1666 	 */
1667 	transport_complete_task_attr(cmd);
1668 	/*
1669 	 * Handle special case for COMPARE_AND_WRITE failure, where the
1670 	 * callback is expected to drop the per device ->caw_sem.
1671 	 */
1672 	if ((cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) &&
1673 	     cmd->transport_complete_callback)
1674 		cmd->transport_complete_callback(cmd, false, &post_ret);
1675 
1676 	switch (sense_reason) {
1677 	case TCM_NON_EXISTENT_LUN:
1678 	case TCM_UNSUPPORTED_SCSI_OPCODE:
1679 	case TCM_INVALID_CDB_FIELD:
1680 	case TCM_INVALID_PARAMETER_LIST:
1681 	case TCM_PARAMETER_LIST_LENGTH_ERROR:
1682 	case TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE:
1683 	case TCM_UNKNOWN_MODE_PAGE:
1684 	case TCM_WRITE_PROTECTED:
1685 	case TCM_ADDRESS_OUT_OF_RANGE:
1686 	case TCM_CHECK_CONDITION_ABORT_CMD:
1687 	case TCM_CHECK_CONDITION_UNIT_ATTENTION:
1688 	case TCM_CHECK_CONDITION_NOT_READY:
1689 	case TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED:
1690 	case TCM_LOGICAL_BLOCK_APP_TAG_CHECK_FAILED:
1691 	case TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED:
1692 	case TCM_COPY_TARGET_DEVICE_NOT_REACHABLE:
1693 	case TCM_TOO_MANY_TARGET_DESCS:
1694 	case TCM_UNSUPPORTED_TARGET_DESC_TYPE_CODE:
1695 	case TCM_TOO_MANY_SEGMENT_DESCS:
1696 	case TCM_UNSUPPORTED_SEGMENT_DESC_TYPE_CODE:
1697 		break;
1698 	case TCM_OUT_OF_RESOURCES:
1699 		sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
1700 		break;
1701 	case TCM_RESERVATION_CONFLICT:
1702 		/*
1703 		 * No SENSE Data payload for this case, set SCSI Status
1704 		 * and queue the response to $FABRIC_MOD.
1705 		 *
1706 		 * Uses linux/include/scsi/scsi.h SAM status codes defs
1707 		 */
1708 		cmd->scsi_status = SAM_STAT_RESERVATION_CONFLICT;
1709 		/*
1710 		 * For UA Interlock Code 11b, a RESERVATION CONFLICT will
1711 		 * establish a UNIT ATTENTION with PREVIOUS RESERVATION
1712 		 * CONFLICT STATUS.
1713 		 *
1714 		 * See spc4r17, section 7.4.6 Control Mode Page, Table 349
1715 		 */
1716 		if (cmd->se_sess &&
1717 		    cmd->se_dev->dev_attrib.emulate_ua_intlck_ctrl == 2) {
1718 			target_ua_allocate_lun(cmd->se_sess->se_node_acl,
1719 					       cmd->orig_fe_lun, 0x2C,
1720 					ASCQ_2CH_PREVIOUS_RESERVATION_CONFLICT_STATUS);
1721 		}
1722 		trace_target_cmd_complete(cmd);
1723 		ret = cmd->se_tfo->queue_status(cmd);
1724 		if (ret)
1725 			goto queue_full;
1726 		goto check_stop;
1727 	default:
1728 		pr_err("Unknown transport error for CDB 0x%02x: %d\n",
1729 			cmd->t_task_cdb[0], sense_reason);
1730 		sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
1731 		break;
1732 	}
1733 
1734 	ret = transport_send_check_condition_and_sense(cmd, sense_reason, 0);
1735 	if (ret)
1736 		goto queue_full;
1737 
1738 check_stop:
1739 	transport_lun_remove_cmd(cmd);
1740 	transport_cmd_check_stop_to_fabric(cmd);
1741 	return;
1742 
1743 queue_full:
1744 	transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
1745 }
1746 EXPORT_SYMBOL(transport_generic_request_failure);
1747 
1748 void __target_execute_cmd(struct se_cmd *cmd, bool do_checks)
1749 {
1750 	sense_reason_t ret;
1751 
1752 	if (!cmd->execute_cmd) {
1753 		ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
1754 		goto err;
1755 	}
1756 	if (do_checks) {
1757 		/*
1758 		 * Check for an existing UNIT ATTENTION condition after
1759 		 * target_handle_task_attr() has done SAM task attr
1760 		 * checking, and possibly have already defered execution
1761 		 * out to target_restart_delayed_cmds() context.
1762 		 */
1763 		ret = target_scsi3_ua_check(cmd);
1764 		if (ret)
1765 			goto err;
1766 
1767 		ret = target_alua_state_check(cmd);
1768 		if (ret)
1769 			goto err;
1770 
1771 		ret = target_check_reservation(cmd);
1772 		if (ret) {
1773 			cmd->scsi_status = SAM_STAT_RESERVATION_CONFLICT;
1774 			goto err;
1775 		}
1776 	}
1777 
1778 	ret = cmd->execute_cmd(cmd);
1779 	if (!ret)
1780 		return;
1781 err:
1782 	spin_lock_irq(&cmd->t_state_lock);
1783 	cmd->transport_state &= ~CMD_T_SENT;
1784 	spin_unlock_irq(&cmd->t_state_lock);
1785 
1786 	transport_generic_request_failure(cmd, ret);
1787 }
1788 
1789 static int target_write_prot_action(struct se_cmd *cmd)
1790 {
1791 	u32 sectors;
1792 	/*
1793 	 * Perform WRITE_INSERT of PI using software emulation when backend
1794 	 * device has PI enabled, if the transport has not already generated
1795 	 * PI using hardware WRITE_INSERT offload.
1796 	 */
1797 	switch (cmd->prot_op) {
1798 	case TARGET_PROT_DOUT_INSERT:
1799 		if (!(cmd->se_sess->sup_prot_ops & TARGET_PROT_DOUT_INSERT))
1800 			sbc_dif_generate(cmd);
1801 		break;
1802 	case TARGET_PROT_DOUT_STRIP:
1803 		if (cmd->se_sess->sup_prot_ops & TARGET_PROT_DOUT_STRIP)
1804 			break;
1805 
1806 		sectors = cmd->data_length >> ilog2(cmd->se_dev->dev_attrib.block_size);
1807 		cmd->pi_err = sbc_dif_verify(cmd, cmd->t_task_lba,
1808 					     sectors, 0, cmd->t_prot_sg, 0);
1809 		if (unlikely(cmd->pi_err)) {
1810 			spin_lock_irq(&cmd->t_state_lock);
1811 			cmd->transport_state &= ~CMD_T_SENT;
1812 			spin_unlock_irq(&cmd->t_state_lock);
1813 			transport_generic_request_failure(cmd, cmd->pi_err);
1814 			return -1;
1815 		}
1816 		break;
1817 	default:
1818 		break;
1819 	}
1820 
1821 	return 0;
1822 }
1823 
1824 static bool target_handle_task_attr(struct se_cmd *cmd)
1825 {
1826 	struct se_device *dev = cmd->se_dev;
1827 
1828 	if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
1829 		return false;
1830 
1831 	cmd->se_cmd_flags |= SCF_TASK_ATTR_SET;
1832 
1833 	/*
1834 	 * Check for the existence of HEAD_OF_QUEUE, and if true return 1
1835 	 * to allow the passed struct se_cmd list of tasks to the front of the list.
1836 	 */
1837 	switch (cmd->sam_task_attr) {
1838 	case TCM_HEAD_TAG:
1839 		pr_debug("Added HEAD_OF_QUEUE for CDB: 0x%02x\n",
1840 			 cmd->t_task_cdb[0]);
1841 		return false;
1842 	case TCM_ORDERED_TAG:
1843 		atomic_inc_mb(&dev->dev_ordered_sync);
1844 
1845 		pr_debug("Added ORDERED for CDB: 0x%02x to ordered list\n",
1846 			 cmd->t_task_cdb[0]);
1847 
1848 		/*
1849 		 * Execute an ORDERED command if no other older commands
1850 		 * exist that need to be completed first.
1851 		 */
1852 		if (!atomic_read(&dev->simple_cmds))
1853 			return false;
1854 		break;
1855 	default:
1856 		/*
1857 		 * For SIMPLE and UNTAGGED Task Attribute commands
1858 		 */
1859 		atomic_inc_mb(&dev->simple_cmds);
1860 		break;
1861 	}
1862 
1863 	if (atomic_read(&dev->dev_ordered_sync) == 0)
1864 		return false;
1865 
1866 	spin_lock(&dev->delayed_cmd_lock);
1867 	list_add_tail(&cmd->se_delayed_node, &dev->delayed_cmd_list);
1868 	spin_unlock(&dev->delayed_cmd_lock);
1869 
1870 	pr_debug("Added CDB: 0x%02x Task Attr: 0x%02x to delayed CMD listn",
1871 		cmd->t_task_cdb[0], cmd->sam_task_attr);
1872 	return true;
1873 }
1874 
1875 static int __transport_check_aborted_status(struct se_cmd *, int);
1876 
1877 void target_execute_cmd(struct se_cmd *cmd)
1878 {
1879 	/*
1880 	 * Determine if frontend context caller is requesting the stopping of
1881 	 * this command for frontend exceptions.
1882 	 *
1883 	 * If the received CDB has aleady been aborted stop processing it here.
1884 	 */
1885 	spin_lock_irq(&cmd->t_state_lock);
1886 	if (__transport_check_aborted_status(cmd, 1)) {
1887 		spin_unlock_irq(&cmd->t_state_lock);
1888 		return;
1889 	}
1890 	if (cmd->transport_state & CMD_T_STOP) {
1891 		pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08llx\n",
1892 			__func__, __LINE__, cmd->tag);
1893 
1894 		spin_unlock_irq(&cmd->t_state_lock);
1895 		complete_all(&cmd->t_transport_stop_comp);
1896 		return;
1897 	}
1898 
1899 	cmd->t_state = TRANSPORT_PROCESSING;
1900 	cmd->transport_state |= CMD_T_ACTIVE | CMD_T_SENT;
1901 	spin_unlock_irq(&cmd->t_state_lock);
1902 
1903 	if (target_write_prot_action(cmd))
1904 		return;
1905 
1906 	if (target_handle_task_attr(cmd)) {
1907 		spin_lock_irq(&cmd->t_state_lock);
1908 		cmd->transport_state &= ~CMD_T_SENT;
1909 		spin_unlock_irq(&cmd->t_state_lock);
1910 		return;
1911 	}
1912 
1913 	__target_execute_cmd(cmd, true);
1914 }
1915 EXPORT_SYMBOL(target_execute_cmd);
1916 
1917 /*
1918  * Process all commands up to the last received ORDERED task attribute which
1919  * requires another blocking boundary
1920  */
1921 static void target_restart_delayed_cmds(struct se_device *dev)
1922 {
1923 	for (;;) {
1924 		struct se_cmd *cmd;
1925 
1926 		spin_lock(&dev->delayed_cmd_lock);
1927 		if (list_empty(&dev->delayed_cmd_list)) {
1928 			spin_unlock(&dev->delayed_cmd_lock);
1929 			break;
1930 		}
1931 
1932 		cmd = list_entry(dev->delayed_cmd_list.next,
1933 				 struct se_cmd, se_delayed_node);
1934 		list_del(&cmd->se_delayed_node);
1935 		spin_unlock(&dev->delayed_cmd_lock);
1936 
1937 		__target_execute_cmd(cmd, true);
1938 
1939 		if (cmd->sam_task_attr == TCM_ORDERED_TAG)
1940 			break;
1941 	}
1942 }
1943 
1944 /*
1945  * Called from I/O completion to determine which dormant/delayed
1946  * and ordered cmds need to have their tasks added to the execution queue.
1947  */
1948 static void transport_complete_task_attr(struct se_cmd *cmd)
1949 {
1950 	struct se_device *dev = cmd->se_dev;
1951 
1952 	if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
1953 		return;
1954 
1955 	if (!(cmd->se_cmd_flags & SCF_TASK_ATTR_SET))
1956 		goto restart;
1957 
1958 	if (cmd->sam_task_attr == TCM_SIMPLE_TAG) {
1959 		atomic_dec_mb(&dev->simple_cmds);
1960 		dev->dev_cur_ordered_id++;
1961 	} else if (cmd->sam_task_attr == TCM_HEAD_TAG) {
1962 		dev->dev_cur_ordered_id++;
1963 		pr_debug("Incremented dev_cur_ordered_id: %u for HEAD_OF_QUEUE\n",
1964 			 dev->dev_cur_ordered_id);
1965 	} else if (cmd->sam_task_attr == TCM_ORDERED_TAG) {
1966 		atomic_dec_mb(&dev->dev_ordered_sync);
1967 
1968 		dev->dev_cur_ordered_id++;
1969 		pr_debug("Incremented dev_cur_ordered_id: %u for ORDERED\n",
1970 			 dev->dev_cur_ordered_id);
1971 	}
1972 restart:
1973 	target_restart_delayed_cmds(dev);
1974 }
1975 
1976 static void transport_complete_qf(struct se_cmd *cmd)
1977 {
1978 	int ret = 0;
1979 
1980 	transport_complete_task_attr(cmd);
1981 	/*
1982 	 * If a fabric driver ->write_pending() or ->queue_data_in() callback
1983 	 * has returned neither -ENOMEM or -EAGAIN, assume it's fatal and
1984 	 * the same callbacks should not be retried.  Return CHECK_CONDITION
1985 	 * if a scsi_status is not already set.
1986 	 *
1987 	 * If a fabric driver ->queue_status() has returned non zero, always
1988 	 * keep retrying no matter what..
1989 	 */
1990 	if (cmd->t_state == TRANSPORT_COMPLETE_QF_ERR) {
1991 		if (cmd->scsi_status)
1992 			goto queue_status;
1993 
1994 		cmd->se_cmd_flags |= SCF_EMULATED_TASK_SENSE;
1995 		cmd->scsi_status = SAM_STAT_CHECK_CONDITION;
1996 		cmd->scsi_sense_length  = TRANSPORT_SENSE_BUFFER;
1997 		translate_sense_reason(cmd, TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE);
1998 		goto queue_status;
1999 	}
2000 
2001 	if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE)
2002 		goto queue_status;
2003 
2004 	switch (cmd->data_direction) {
2005 	case DMA_FROM_DEVICE:
2006 		if (cmd->scsi_status)
2007 			goto queue_status;
2008 
2009 		trace_target_cmd_complete(cmd);
2010 		ret = cmd->se_tfo->queue_data_in(cmd);
2011 		break;
2012 	case DMA_TO_DEVICE:
2013 		if (cmd->se_cmd_flags & SCF_BIDI) {
2014 			ret = cmd->se_tfo->queue_data_in(cmd);
2015 			break;
2016 		}
2017 		/* Fall through for DMA_TO_DEVICE */
2018 	case DMA_NONE:
2019 queue_status:
2020 		trace_target_cmd_complete(cmd);
2021 		ret = cmd->se_tfo->queue_status(cmd);
2022 		break;
2023 	default:
2024 		break;
2025 	}
2026 
2027 	if (ret < 0) {
2028 		transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
2029 		return;
2030 	}
2031 	transport_lun_remove_cmd(cmd);
2032 	transport_cmd_check_stop_to_fabric(cmd);
2033 }
2034 
2035 static void transport_handle_queue_full(struct se_cmd *cmd, struct se_device *dev,
2036 					int err, bool write_pending)
2037 {
2038 	/*
2039 	 * -EAGAIN or -ENOMEM signals retry of ->write_pending() and/or
2040 	 * ->queue_data_in() callbacks from new process context.
2041 	 *
2042 	 * Otherwise for other errors, transport_complete_qf() will send
2043 	 * CHECK_CONDITION via ->queue_status() instead of attempting to
2044 	 * retry associated fabric driver data-transfer callbacks.
2045 	 */
2046 	if (err == -EAGAIN || err == -ENOMEM) {
2047 		cmd->t_state = (write_pending) ? TRANSPORT_COMPLETE_QF_WP :
2048 						 TRANSPORT_COMPLETE_QF_OK;
2049 	} else {
2050 		pr_warn_ratelimited("Got unknown fabric queue status: %d\n", err);
2051 		cmd->t_state = TRANSPORT_COMPLETE_QF_ERR;
2052 	}
2053 
2054 	spin_lock_irq(&dev->qf_cmd_lock);
2055 	list_add_tail(&cmd->se_qf_node, &cmd->se_dev->qf_cmd_list);
2056 	atomic_inc_mb(&dev->dev_qf_count);
2057 	spin_unlock_irq(&cmd->se_dev->qf_cmd_lock);
2058 
2059 	schedule_work(&cmd->se_dev->qf_work_queue);
2060 }
2061 
2062 static bool target_read_prot_action(struct se_cmd *cmd)
2063 {
2064 	switch (cmd->prot_op) {
2065 	case TARGET_PROT_DIN_STRIP:
2066 		if (!(cmd->se_sess->sup_prot_ops & TARGET_PROT_DIN_STRIP)) {
2067 			u32 sectors = cmd->data_length >>
2068 				  ilog2(cmd->se_dev->dev_attrib.block_size);
2069 
2070 			cmd->pi_err = sbc_dif_verify(cmd, cmd->t_task_lba,
2071 						     sectors, 0, cmd->t_prot_sg,
2072 						     0);
2073 			if (cmd->pi_err)
2074 				return true;
2075 		}
2076 		break;
2077 	case TARGET_PROT_DIN_INSERT:
2078 		if (cmd->se_sess->sup_prot_ops & TARGET_PROT_DIN_INSERT)
2079 			break;
2080 
2081 		sbc_dif_generate(cmd);
2082 		break;
2083 	default:
2084 		break;
2085 	}
2086 
2087 	return false;
2088 }
2089 
2090 static void target_complete_ok_work(struct work_struct *work)
2091 {
2092 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
2093 	int ret;
2094 
2095 	/*
2096 	 * Check if we need to move delayed/dormant tasks from cmds on the
2097 	 * delayed execution list after a HEAD_OF_QUEUE or ORDERED Task
2098 	 * Attribute.
2099 	 */
2100 	transport_complete_task_attr(cmd);
2101 
2102 	/*
2103 	 * Check to schedule QUEUE_FULL work, or execute an existing
2104 	 * cmd->transport_qf_callback()
2105 	 */
2106 	if (atomic_read(&cmd->se_dev->dev_qf_count) != 0)
2107 		schedule_work(&cmd->se_dev->qf_work_queue);
2108 
2109 	/*
2110 	 * Check if we need to send a sense buffer from
2111 	 * the struct se_cmd in question.
2112 	 */
2113 	if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) {
2114 		WARN_ON(!cmd->scsi_status);
2115 		ret = transport_send_check_condition_and_sense(
2116 					cmd, 0, 1);
2117 		if (ret)
2118 			goto queue_full;
2119 
2120 		transport_lun_remove_cmd(cmd);
2121 		transport_cmd_check_stop_to_fabric(cmd);
2122 		return;
2123 	}
2124 	/*
2125 	 * Check for a callback, used by amongst other things
2126 	 * XDWRITE_READ_10 and COMPARE_AND_WRITE emulation.
2127 	 */
2128 	if (cmd->transport_complete_callback) {
2129 		sense_reason_t rc;
2130 		bool caw = (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE);
2131 		bool zero_dl = !(cmd->data_length);
2132 		int post_ret = 0;
2133 
2134 		rc = cmd->transport_complete_callback(cmd, true, &post_ret);
2135 		if (!rc && !post_ret) {
2136 			if (caw && zero_dl)
2137 				goto queue_rsp;
2138 
2139 			return;
2140 		} else if (rc) {
2141 			ret = transport_send_check_condition_and_sense(cmd,
2142 						rc, 0);
2143 			if (ret)
2144 				goto queue_full;
2145 
2146 			transport_lun_remove_cmd(cmd);
2147 			transport_cmd_check_stop_to_fabric(cmd);
2148 			return;
2149 		}
2150 	}
2151 
2152 queue_rsp:
2153 	switch (cmd->data_direction) {
2154 	case DMA_FROM_DEVICE:
2155 		if (cmd->scsi_status)
2156 			goto queue_status;
2157 
2158 		atomic_long_add(cmd->data_length,
2159 				&cmd->se_lun->lun_stats.tx_data_octets);
2160 		/*
2161 		 * Perform READ_STRIP of PI using software emulation when
2162 		 * backend had PI enabled, if the transport will not be
2163 		 * performing hardware READ_STRIP offload.
2164 		 */
2165 		if (target_read_prot_action(cmd)) {
2166 			ret = transport_send_check_condition_and_sense(cmd,
2167 						cmd->pi_err, 0);
2168 			if (ret)
2169 				goto queue_full;
2170 
2171 			transport_lun_remove_cmd(cmd);
2172 			transport_cmd_check_stop_to_fabric(cmd);
2173 			return;
2174 		}
2175 
2176 		trace_target_cmd_complete(cmd);
2177 		ret = cmd->se_tfo->queue_data_in(cmd);
2178 		if (ret)
2179 			goto queue_full;
2180 		break;
2181 	case DMA_TO_DEVICE:
2182 		atomic_long_add(cmd->data_length,
2183 				&cmd->se_lun->lun_stats.rx_data_octets);
2184 		/*
2185 		 * Check if we need to send READ payload for BIDI-COMMAND
2186 		 */
2187 		if (cmd->se_cmd_flags & SCF_BIDI) {
2188 			atomic_long_add(cmd->data_length,
2189 					&cmd->se_lun->lun_stats.tx_data_octets);
2190 			ret = cmd->se_tfo->queue_data_in(cmd);
2191 			if (ret)
2192 				goto queue_full;
2193 			break;
2194 		}
2195 		/* Fall through for DMA_TO_DEVICE */
2196 	case DMA_NONE:
2197 queue_status:
2198 		trace_target_cmd_complete(cmd);
2199 		ret = cmd->se_tfo->queue_status(cmd);
2200 		if (ret)
2201 			goto queue_full;
2202 		break;
2203 	default:
2204 		break;
2205 	}
2206 
2207 	transport_lun_remove_cmd(cmd);
2208 	transport_cmd_check_stop_to_fabric(cmd);
2209 	return;
2210 
2211 queue_full:
2212 	pr_debug("Handling complete_ok QUEUE_FULL: se_cmd: %p,"
2213 		" data_direction: %d\n", cmd, cmd->data_direction);
2214 
2215 	transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
2216 }
2217 
2218 void target_free_sgl(struct scatterlist *sgl, int nents)
2219 {
2220 	struct scatterlist *sg;
2221 	int count;
2222 
2223 	for_each_sg(sgl, sg, nents, count)
2224 		__free_page(sg_page(sg));
2225 
2226 	kfree(sgl);
2227 }
2228 EXPORT_SYMBOL(target_free_sgl);
2229 
2230 static inline void transport_reset_sgl_orig(struct se_cmd *cmd)
2231 {
2232 	/*
2233 	 * Check for saved t_data_sg that may be used for COMPARE_AND_WRITE
2234 	 * emulation, and free + reset pointers if necessary..
2235 	 */
2236 	if (!cmd->t_data_sg_orig)
2237 		return;
2238 
2239 	kfree(cmd->t_data_sg);
2240 	cmd->t_data_sg = cmd->t_data_sg_orig;
2241 	cmd->t_data_sg_orig = NULL;
2242 	cmd->t_data_nents = cmd->t_data_nents_orig;
2243 	cmd->t_data_nents_orig = 0;
2244 }
2245 
2246 static inline void transport_free_pages(struct se_cmd *cmd)
2247 {
2248 	if (!(cmd->se_cmd_flags & SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC)) {
2249 		target_free_sgl(cmd->t_prot_sg, cmd->t_prot_nents);
2250 		cmd->t_prot_sg = NULL;
2251 		cmd->t_prot_nents = 0;
2252 	}
2253 
2254 	if (cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) {
2255 		/*
2256 		 * Release special case READ buffer payload required for
2257 		 * SG_TO_MEM_NOALLOC to function with COMPARE_AND_WRITE
2258 		 */
2259 		if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) {
2260 			target_free_sgl(cmd->t_bidi_data_sg,
2261 					   cmd->t_bidi_data_nents);
2262 			cmd->t_bidi_data_sg = NULL;
2263 			cmd->t_bidi_data_nents = 0;
2264 		}
2265 		transport_reset_sgl_orig(cmd);
2266 		return;
2267 	}
2268 	transport_reset_sgl_orig(cmd);
2269 
2270 	target_free_sgl(cmd->t_data_sg, cmd->t_data_nents);
2271 	cmd->t_data_sg = NULL;
2272 	cmd->t_data_nents = 0;
2273 
2274 	target_free_sgl(cmd->t_bidi_data_sg, cmd->t_bidi_data_nents);
2275 	cmd->t_bidi_data_sg = NULL;
2276 	cmd->t_bidi_data_nents = 0;
2277 }
2278 
2279 /**
2280  * transport_put_cmd - release a reference to a command
2281  * @cmd:       command to release
2282  *
2283  * This routine releases our reference to the command and frees it if possible.
2284  */
2285 static int transport_put_cmd(struct se_cmd *cmd)
2286 {
2287 	BUG_ON(!cmd->se_tfo);
2288 	/*
2289 	 * If this cmd has been setup with target_get_sess_cmd(), drop
2290 	 * the kref and call ->release_cmd() in kref callback.
2291 	 */
2292 	return target_put_sess_cmd(cmd);
2293 }
2294 
2295 void *transport_kmap_data_sg(struct se_cmd *cmd)
2296 {
2297 	struct scatterlist *sg = cmd->t_data_sg;
2298 	struct page **pages;
2299 	int i;
2300 
2301 	/*
2302 	 * We need to take into account a possible offset here for fabrics like
2303 	 * tcm_loop who may be using a contig buffer from the SCSI midlayer for
2304 	 * control CDBs passed as SGLs via transport_generic_map_mem_to_cmd()
2305 	 */
2306 	if (!cmd->t_data_nents)
2307 		return NULL;
2308 
2309 	BUG_ON(!sg);
2310 	if (cmd->t_data_nents == 1)
2311 		return kmap(sg_page(sg)) + sg->offset;
2312 
2313 	/* >1 page. use vmap */
2314 	pages = kmalloc(sizeof(*pages) * cmd->t_data_nents, GFP_KERNEL);
2315 	if (!pages)
2316 		return NULL;
2317 
2318 	/* convert sg[] to pages[] */
2319 	for_each_sg(cmd->t_data_sg, sg, cmd->t_data_nents, i) {
2320 		pages[i] = sg_page(sg);
2321 	}
2322 
2323 	cmd->t_data_vmap = vmap(pages, cmd->t_data_nents,  VM_MAP, PAGE_KERNEL);
2324 	kfree(pages);
2325 	if (!cmd->t_data_vmap)
2326 		return NULL;
2327 
2328 	return cmd->t_data_vmap + cmd->t_data_sg[0].offset;
2329 }
2330 EXPORT_SYMBOL(transport_kmap_data_sg);
2331 
2332 void transport_kunmap_data_sg(struct se_cmd *cmd)
2333 {
2334 	if (!cmd->t_data_nents) {
2335 		return;
2336 	} else if (cmd->t_data_nents == 1) {
2337 		kunmap(sg_page(cmd->t_data_sg));
2338 		return;
2339 	}
2340 
2341 	vunmap(cmd->t_data_vmap);
2342 	cmd->t_data_vmap = NULL;
2343 }
2344 EXPORT_SYMBOL(transport_kunmap_data_sg);
2345 
2346 int
2347 target_alloc_sgl(struct scatterlist **sgl, unsigned int *nents, u32 length,
2348 		 bool zero_page, bool chainable)
2349 {
2350 	struct scatterlist *sg;
2351 	struct page *page;
2352 	gfp_t zero_flag = (zero_page) ? __GFP_ZERO : 0;
2353 	unsigned int nalloc, nent;
2354 	int i = 0;
2355 
2356 	nalloc = nent = DIV_ROUND_UP(length, PAGE_SIZE);
2357 	if (chainable)
2358 		nalloc++;
2359 	sg = kmalloc_array(nalloc, sizeof(struct scatterlist), GFP_KERNEL);
2360 	if (!sg)
2361 		return -ENOMEM;
2362 
2363 	sg_init_table(sg, nalloc);
2364 
2365 	while (length) {
2366 		u32 page_len = min_t(u32, length, PAGE_SIZE);
2367 		page = alloc_page(GFP_KERNEL | zero_flag);
2368 		if (!page)
2369 			goto out;
2370 
2371 		sg_set_page(&sg[i], page, page_len, 0);
2372 		length -= page_len;
2373 		i++;
2374 	}
2375 	*sgl = sg;
2376 	*nents = nent;
2377 	return 0;
2378 
2379 out:
2380 	while (i > 0) {
2381 		i--;
2382 		__free_page(sg_page(&sg[i]));
2383 	}
2384 	kfree(sg);
2385 	return -ENOMEM;
2386 }
2387 EXPORT_SYMBOL(target_alloc_sgl);
2388 
2389 /*
2390  * Allocate any required resources to execute the command.  For writes we
2391  * might not have the payload yet, so notify the fabric via a call to
2392  * ->write_pending instead. Otherwise place it on the execution queue.
2393  */
2394 sense_reason_t
2395 transport_generic_new_cmd(struct se_cmd *cmd)
2396 {
2397 	unsigned long flags;
2398 	int ret = 0;
2399 	bool zero_flag = !(cmd->se_cmd_flags & SCF_SCSI_DATA_CDB);
2400 
2401 	if (cmd->prot_op != TARGET_PROT_NORMAL &&
2402 	    !(cmd->se_cmd_flags & SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC)) {
2403 		ret = target_alloc_sgl(&cmd->t_prot_sg, &cmd->t_prot_nents,
2404 				       cmd->prot_length, true, false);
2405 		if (ret < 0)
2406 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2407 	}
2408 
2409 	/*
2410 	 * Determine is the TCM fabric module has already allocated physical
2411 	 * memory, and is directly calling transport_generic_map_mem_to_cmd()
2412 	 * beforehand.
2413 	 */
2414 	if (!(cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) &&
2415 	    cmd->data_length) {
2416 
2417 		if ((cmd->se_cmd_flags & SCF_BIDI) ||
2418 		    (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE)) {
2419 			u32 bidi_length;
2420 
2421 			if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE)
2422 				bidi_length = cmd->t_task_nolb *
2423 					      cmd->se_dev->dev_attrib.block_size;
2424 			else
2425 				bidi_length = cmd->data_length;
2426 
2427 			ret = target_alloc_sgl(&cmd->t_bidi_data_sg,
2428 					       &cmd->t_bidi_data_nents,
2429 					       bidi_length, zero_flag, false);
2430 			if (ret < 0)
2431 				return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2432 		}
2433 
2434 		ret = target_alloc_sgl(&cmd->t_data_sg, &cmd->t_data_nents,
2435 				       cmd->data_length, zero_flag, false);
2436 		if (ret < 0)
2437 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2438 	} else if ((cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) &&
2439 		    cmd->data_length) {
2440 		/*
2441 		 * Special case for COMPARE_AND_WRITE with fabrics
2442 		 * using SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC.
2443 		 */
2444 		u32 caw_length = cmd->t_task_nolb *
2445 				 cmd->se_dev->dev_attrib.block_size;
2446 
2447 		ret = target_alloc_sgl(&cmd->t_bidi_data_sg,
2448 				       &cmd->t_bidi_data_nents,
2449 				       caw_length, zero_flag, false);
2450 		if (ret < 0)
2451 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2452 	}
2453 	/*
2454 	 * If this command is not a write we can execute it right here,
2455 	 * for write buffers we need to notify the fabric driver first
2456 	 * and let it call back once the write buffers are ready.
2457 	 */
2458 	target_add_to_state_list(cmd);
2459 	if (cmd->data_direction != DMA_TO_DEVICE || cmd->data_length == 0) {
2460 		target_execute_cmd(cmd);
2461 		return 0;
2462 	}
2463 
2464 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2465 	cmd->t_state = TRANSPORT_WRITE_PENDING;
2466 	/*
2467 	 * Determine if frontend context caller is requesting the stopping of
2468 	 * this command for frontend exceptions.
2469 	 */
2470 	if (cmd->transport_state & CMD_T_STOP) {
2471 		pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08llx\n",
2472 			 __func__, __LINE__, cmd->tag);
2473 
2474 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2475 
2476 		complete_all(&cmd->t_transport_stop_comp);
2477 		return 0;
2478 	}
2479 	cmd->transport_state &= ~CMD_T_ACTIVE;
2480 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2481 
2482 	ret = cmd->se_tfo->write_pending(cmd);
2483 	if (ret)
2484 		goto queue_full;
2485 
2486 	return 0;
2487 
2488 queue_full:
2489 	pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n", cmd);
2490 	transport_handle_queue_full(cmd, cmd->se_dev, ret, true);
2491 	return 0;
2492 }
2493 EXPORT_SYMBOL(transport_generic_new_cmd);
2494 
2495 static void transport_write_pending_qf(struct se_cmd *cmd)
2496 {
2497 	int ret;
2498 
2499 	ret = cmd->se_tfo->write_pending(cmd);
2500 	if (ret) {
2501 		pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n",
2502 			 cmd);
2503 		transport_handle_queue_full(cmd, cmd->se_dev, ret, true);
2504 	}
2505 }
2506 
2507 static bool
2508 __transport_wait_for_tasks(struct se_cmd *, bool, bool *, bool *,
2509 			   unsigned long *flags);
2510 
2511 static void target_wait_free_cmd(struct se_cmd *cmd, bool *aborted, bool *tas)
2512 {
2513 	unsigned long flags;
2514 
2515 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2516 	__transport_wait_for_tasks(cmd, true, aborted, tas, &flags);
2517 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2518 }
2519 
2520 int transport_generic_free_cmd(struct se_cmd *cmd, int wait_for_tasks)
2521 {
2522 	int ret = 0;
2523 	bool aborted = false, tas = false;
2524 
2525 	if (!(cmd->se_cmd_flags & SCF_SE_LUN_CMD)) {
2526 		if (wait_for_tasks && (cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
2527 			target_wait_free_cmd(cmd, &aborted, &tas);
2528 
2529 		if (!aborted || tas)
2530 			ret = transport_put_cmd(cmd);
2531 	} else {
2532 		if (wait_for_tasks)
2533 			target_wait_free_cmd(cmd, &aborted, &tas);
2534 		/*
2535 		 * Handle WRITE failure case where transport_generic_new_cmd()
2536 		 * has already added se_cmd to state_list, but fabric has
2537 		 * failed command before I/O submission.
2538 		 */
2539 		if (cmd->state_active)
2540 			target_remove_from_state_list(cmd);
2541 
2542 		if (cmd->se_lun)
2543 			transport_lun_remove_cmd(cmd);
2544 
2545 		if (!aborted || tas)
2546 			ret = transport_put_cmd(cmd);
2547 	}
2548 	/*
2549 	 * If the task has been internally aborted due to TMR ABORT_TASK
2550 	 * or LUN_RESET, target_core_tmr.c is responsible for performing
2551 	 * the remaining calls to target_put_sess_cmd(), and not the
2552 	 * callers of this function.
2553 	 */
2554 	if (aborted) {
2555 		pr_debug("Detected CMD_T_ABORTED for ITT: %llu\n", cmd->tag);
2556 		wait_for_completion(&cmd->cmd_wait_comp);
2557 		cmd->se_tfo->release_cmd(cmd);
2558 		ret = 1;
2559 	}
2560 	return ret;
2561 }
2562 EXPORT_SYMBOL(transport_generic_free_cmd);
2563 
2564 /* target_get_sess_cmd - Add command to active ->sess_cmd_list
2565  * @se_cmd:	command descriptor to add
2566  * @ack_kref:	Signal that fabric will perform an ack target_put_sess_cmd()
2567  */
2568 int target_get_sess_cmd(struct se_cmd *se_cmd, bool ack_kref)
2569 {
2570 	struct se_session *se_sess = se_cmd->se_sess;
2571 	unsigned long flags;
2572 	int ret = 0;
2573 
2574 	/*
2575 	 * Add a second kref if the fabric caller is expecting to handle
2576 	 * fabric acknowledgement that requires two target_put_sess_cmd()
2577 	 * invocations before se_cmd descriptor release.
2578 	 */
2579 	if (ack_kref) {
2580 		if (!kref_get_unless_zero(&se_cmd->cmd_kref))
2581 			return -EINVAL;
2582 
2583 		se_cmd->se_cmd_flags |= SCF_ACK_KREF;
2584 	}
2585 
2586 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2587 	if (se_sess->sess_tearing_down) {
2588 		ret = -ESHUTDOWN;
2589 		goto out;
2590 	}
2591 	list_add_tail(&se_cmd->se_cmd_list, &se_sess->sess_cmd_list);
2592 out:
2593 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2594 
2595 	if (ret && ack_kref)
2596 		target_put_sess_cmd(se_cmd);
2597 
2598 	return ret;
2599 }
2600 EXPORT_SYMBOL(target_get_sess_cmd);
2601 
2602 static void target_free_cmd_mem(struct se_cmd *cmd)
2603 {
2604 	transport_free_pages(cmd);
2605 
2606 	if (cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
2607 		core_tmr_release_req(cmd->se_tmr_req);
2608 	if (cmd->t_task_cdb != cmd->__t_task_cdb)
2609 		kfree(cmd->t_task_cdb);
2610 }
2611 
2612 static void target_release_cmd_kref(struct kref *kref)
2613 {
2614 	struct se_cmd *se_cmd = container_of(kref, struct se_cmd, cmd_kref);
2615 	struct se_session *se_sess = se_cmd->se_sess;
2616 	unsigned long flags;
2617 	bool fabric_stop;
2618 
2619 	if (se_sess) {
2620 		spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2621 
2622 		spin_lock(&se_cmd->t_state_lock);
2623 		fabric_stop = (se_cmd->transport_state & CMD_T_FABRIC_STOP) &&
2624 			      (se_cmd->transport_state & CMD_T_ABORTED);
2625 		spin_unlock(&se_cmd->t_state_lock);
2626 
2627 		if (se_cmd->cmd_wait_set || fabric_stop) {
2628 			list_del_init(&se_cmd->se_cmd_list);
2629 			spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2630 			target_free_cmd_mem(se_cmd);
2631 			complete(&se_cmd->cmd_wait_comp);
2632 			return;
2633 		}
2634 		list_del_init(&se_cmd->se_cmd_list);
2635 		spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2636 	}
2637 
2638 	target_free_cmd_mem(se_cmd);
2639 	se_cmd->se_tfo->release_cmd(se_cmd);
2640 }
2641 
2642 /**
2643  * target_put_sess_cmd - decrease the command reference count
2644  * @se_cmd:	command to drop a reference from
2645  *
2646  * Returns 1 if and only if this target_put_sess_cmd() call caused the
2647  * refcount to drop to zero. Returns zero otherwise.
2648  */
2649 int target_put_sess_cmd(struct se_cmd *se_cmd)
2650 {
2651 	return kref_put(&se_cmd->cmd_kref, target_release_cmd_kref);
2652 }
2653 EXPORT_SYMBOL(target_put_sess_cmd);
2654 
2655 /* target_sess_cmd_list_set_waiting - Flag all commands in
2656  *         sess_cmd_list to complete cmd_wait_comp.  Set
2657  *         sess_tearing_down so no more commands are queued.
2658  * @se_sess:	session to flag
2659  */
2660 void target_sess_cmd_list_set_waiting(struct se_session *se_sess)
2661 {
2662 	struct se_cmd *se_cmd, *tmp_cmd;
2663 	unsigned long flags;
2664 	int rc;
2665 
2666 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2667 	if (se_sess->sess_tearing_down) {
2668 		spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2669 		return;
2670 	}
2671 	se_sess->sess_tearing_down = 1;
2672 	list_splice_init(&se_sess->sess_cmd_list, &se_sess->sess_wait_list);
2673 
2674 	list_for_each_entry_safe(se_cmd, tmp_cmd,
2675 				 &se_sess->sess_wait_list, se_cmd_list) {
2676 		rc = kref_get_unless_zero(&se_cmd->cmd_kref);
2677 		if (rc) {
2678 			se_cmd->cmd_wait_set = 1;
2679 			spin_lock(&se_cmd->t_state_lock);
2680 			se_cmd->transport_state |= CMD_T_FABRIC_STOP;
2681 			spin_unlock(&se_cmd->t_state_lock);
2682 		} else
2683 			list_del_init(&se_cmd->se_cmd_list);
2684 	}
2685 
2686 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2687 }
2688 EXPORT_SYMBOL(target_sess_cmd_list_set_waiting);
2689 
2690 /* target_wait_for_sess_cmds - Wait for outstanding descriptors
2691  * @se_sess:    session to wait for active I/O
2692  */
2693 void target_wait_for_sess_cmds(struct se_session *se_sess)
2694 {
2695 	struct se_cmd *se_cmd, *tmp_cmd;
2696 	unsigned long flags;
2697 	bool tas;
2698 
2699 	list_for_each_entry_safe(se_cmd, tmp_cmd,
2700 				&se_sess->sess_wait_list, se_cmd_list) {
2701 		pr_debug("Waiting for se_cmd: %p t_state: %d, fabric state:"
2702 			" %d\n", se_cmd, se_cmd->t_state,
2703 			se_cmd->se_tfo->get_cmd_state(se_cmd));
2704 
2705 		spin_lock_irqsave(&se_cmd->t_state_lock, flags);
2706 		tas = (se_cmd->transport_state & CMD_T_TAS);
2707 		spin_unlock_irqrestore(&se_cmd->t_state_lock, flags);
2708 
2709 		if (!target_put_sess_cmd(se_cmd)) {
2710 			if (tas)
2711 				target_put_sess_cmd(se_cmd);
2712 		}
2713 
2714 		wait_for_completion(&se_cmd->cmd_wait_comp);
2715 		pr_debug("After cmd_wait_comp: se_cmd: %p t_state: %d"
2716 			" fabric state: %d\n", se_cmd, se_cmd->t_state,
2717 			se_cmd->se_tfo->get_cmd_state(se_cmd));
2718 
2719 		se_cmd->se_tfo->release_cmd(se_cmd);
2720 	}
2721 
2722 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2723 	WARN_ON(!list_empty(&se_sess->sess_cmd_list));
2724 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2725 
2726 }
2727 EXPORT_SYMBOL(target_wait_for_sess_cmds);
2728 
2729 static void target_lun_confirm(struct percpu_ref *ref)
2730 {
2731 	struct se_lun *lun = container_of(ref, struct se_lun, lun_ref);
2732 
2733 	complete(&lun->lun_ref_comp);
2734 }
2735 
2736 void transport_clear_lun_ref(struct se_lun *lun)
2737 {
2738 	/*
2739 	 * Mark the percpu-ref as DEAD, switch to atomic_t mode, drop
2740 	 * the initial reference and schedule confirm kill to be
2741 	 * executed after one full RCU grace period has completed.
2742 	 */
2743 	percpu_ref_kill_and_confirm(&lun->lun_ref, target_lun_confirm);
2744 	/*
2745 	 * The first completion waits for percpu_ref_switch_to_atomic_rcu()
2746 	 * to call target_lun_confirm after lun->lun_ref has been marked
2747 	 * as __PERCPU_REF_DEAD on all CPUs, and switches to atomic_t
2748 	 * mode so that percpu_ref_tryget_live() lookup of lun->lun_ref
2749 	 * fails for all new incoming I/O.
2750 	 */
2751 	wait_for_completion(&lun->lun_ref_comp);
2752 	/*
2753 	 * The second completion waits for percpu_ref_put_many() to
2754 	 * invoke ->release() after lun->lun_ref has switched to
2755 	 * atomic_t mode, and lun->lun_ref.count has reached zero.
2756 	 *
2757 	 * At this point all target-core lun->lun_ref references have
2758 	 * been dropped via transport_lun_remove_cmd(), and it's safe
2759 	 * to proceed with the remaining LUN shutdown.
2760 	 */
2761 	wait_for_completion(&lun->lun_shutdown_comp);
2762 }
2763 
2764 static bool
2765 __transport_wait_for_tasks(struct se_cmd *cmd, bool fabric_stop,
2766 			   bool *aborted, bool *tas, unsigned long *flags)
2767 	__releases(&cmd->t_state_lock)
2768 	__acquires(&cmd->t_state_lock)
2769 {
2770 
2771 	assert_spin_locked(&cmd->t_state_lock);
2772 	WARN_ON_ONCE(!irqs_disabled());
2773 
2774 	if (fabric_stop)
2775 		cmd->transport_state |= CMD_T_FABRIC_STOP;
2776 
2777 	if (cmd->transport_state & CMD_T_ABORTED)
2778 		*aborted = true;
2779 
2780 	if (cmd->transport_state & CMD_T_TAS)
2781 		*tas = true;
2782 
2783 	if (!(cmd->se_cmd_flags & SCF_SE_LUN_CMD) &&
2784 	    !(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
2785 		return false;
2786 
2787 	if (!(cmd->se_cmd_flags & SCF_SUPPORTED_SAM_OPCODE) &&
2788 	    !(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
2789 		return false;
2790 
2791 	if (!(cmd->transport_state & CMD_T_ACTIVE))
2792 		return false;
2793 
2794 	if (fabric_stop && *aborted)
2795 		return false;
2796 
2797 	cmd->transport_state |= CMD_T_STOP;
2798 
2799 	pr_debug("wait_for_tasks: Stopping %p ITT: 0x%08llx i_state: %d,"
2800 		 " t_state: %d, CMD_T_STOP\n", cmd, cmd->tag,
2801 		 cmd->se_tfo->get_cmd_state(cmd), cmd->t_state);
2802 
2803 	spin_unlock_irqrestore(&cmd->t_state_lock, *flags);
2804 
2805 	wait_for_completion(&cmd->t_transport_stop_comp);
2806 
2807 	spin_lock_irqsave(&cmd->t_state_lock, *flags);
2808 	cmd->transport_state &= ~(CMD_T_ACTIVE | CMD_T_STOP);
2809 
2810 	pr_debug("wait_for_tasks: Stopped wait_for_completion(&cmd->"
2811 		 "t_transport_stop_comp) for ITT: 0x%08llx\n", cmd->tag);
2812 
2813 	return true;
2814 }
2815 
2816 /**
2817  * transport_wait_for_tasks - set CMD_T_STOP and wait for t_transport_stop_comp
2818  * @cmd: command to wait on
2819  */
2820 bool transport_wait_for_tasks(struct se_cmd *cmd)
2821 {
2822 	unsigned long flags;
2823 	bool ret, aborted = false, tas = false;
2824 
2825 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2826 	ret = __transport_wait_for_tasks(cmd, false, &aborted, &tas, &flags);
2827 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2828 
2829 	return ret;
2830 }
2831 EXPORT_SYMBOL(transport_wait_for_tasks);
2832 
2833 struct sense_info {
2834 	u8 key;
2835 	u8 asc;
2836 	u8 ascq;
2837 	bool add_sector_info;
2838 };
2839 
2840 static const struct sense_info sense_info_table[] = {
2841 	[TCM_NO_SENSE] = {
2842 		.key = NOT_READY
2843 	},
2844 	[TCM_NON_EXISTENT_LUN] = {
2845 		.key = ILLEGAL_REQUEST,
2846 		.asc = 0x25 /* LOGICAL UNIT NOT SUPPORTED */
2847 	},
2848 	[TCM_UNSUPPORTED_SCSI_OPCODE] = {
2849 		.key = ILLEGAL_REQUEST,
2850 		.asc = 0x20, /* INVALID COMMAND OPERATION CODE */
2851 	},
2852 	[TCM_SECTOR_COUNT_TOO_MANY] = {
2853 		.key = ILLEGAL_REQUEST,
2854 		.asc = 0x20, /* INVALID COMMAND OPERATION CODE */
2855 	},
2856 	[TCM_UNKNOWN_MODE_PAGE] = {
2857 		.key = ILLEGAL_REQUEST,
2858 		.asc = 0x24, /* INVALID FIELD IN CDB */
2859 	},
2860 	[TCM_CHECK_CONDITION_ABORT_CMD] = {
2861 		.key = ABORTED_COMMAND,
2862 		.asc = 0x29, /* BUS DEVICE RESET FUNCTION OCCURRED */
2863 		.ascq = 0x03,
2864 	},
2865 	[TCM_INCORRECT_AMOUNT_OF_DATA] = {
2866 		.key = ABORTED_COMMAND,
2867 		.asc = 0x0c, /* WRITE ERROR */
2868 		.ascq = 0x0d, /* NOT ENOUGH UNSOLICITED DATA */
2869 	},
2870 	[TCM_INVALID_CDB_FIELD] = {
2871 		.key = ILLEGAL_REQUEST,
2872 		.asc = 0x24, /* INVALID FIELD IN CDB */
2873 	},
2874 	[TCM_INVALID_PARAMETER_LIST] = {
2875 		.key = ILLEGAL_REQUEST,
2876 		.asc = 0x26, /* INVALID FIELD IN PARAMETER LIST */
2877 	},
2878 	[TCM_TOO_MANY_TARGET_DESCS] = {
2879 		.key = ILLEGAL_REQUEST,
2880 		.asc = 0x26,
2881 		.ascq = 0x06, /* TOO MANY TARGET DESCRIPTORS */
2882 	},
2883 	[TCM_UNSUPPORTED_TARGET_DESC_TYPE_CODE] = {
2884 		.key = ILLEGAL_REQUEST,
2885 		.asc = 0x26,
2886 		.ascq = 0x07, /* UNSUPPORTED TARGET DESCRIPTOR TYPE CODE */
2887 	},
2888 	[TCM_TOO_MANY_SEGMENT_DESCS] = {
2889 		.key = ILLEGAL_REQUEST,
2890 		.asc = 0x26,
2891 		.ascq = 0x08, /* TOO MANY SEGMENT DESCRIPTORS */
2892 	},
2893 	[TCM_UNSUPPORTED_SEGMENT_DESC_TYPE_CODE] = {
2894 		.key = ILLEGAL_REQUEST,
2895 		.asc = 0x26,
2896 		.ascq = 0x09, /* UNSUPPORTED SEGMENT DESCRIPTOR TYPE CODE */
2897 	},
2898 	[TCM_PARAMETER_LIST_LENGTH_ERROR] = {
2899 		.key = ILLEGAL_REQUEST,
2900 		.asc = 0x1a, /* PARAMETER LIST LENGTH ERROR */
2901 	},
2902 	[TCM_UNEXPECTED_UNSOLICITED_DATA] = {
2903 		.key = ILLEGAL_REQUEST,
2904 		.asc = 0x0c, /* WRITE ERROR */
2905 		.ascq = 0x0c, /* UNEXPECTED_UNSOLICITED_DATA */
2906 	},
2907 	[TCM_SERVICE_CRC_ERROR] = {
2908 		.key = ABORTED_COMMAND,
2909 		.asc = 0x47, /* PROTOCOL SERVICE CRC ERROR */
2910 		.ascq = 0x05, /* N/A */
2911 	},
2912 	[TCM_SNACK_REJECTED] = {
2913 		.key = ABORTED_COMMAND,
2914 		.asc = 0x11, /* READ ERROR */
2915 		.ascq = 0x13, /* FAILED RETRANSMISSION REQUEST */
2916 	},
2917 	[TCM_WRITE_PROTECTED] = {
2918 		.key = DATA_PROTECT,
2919 		.asc = 0x27, /* WRITE PROTECTED */
2920 	},
2921 	[TCM_ADDRESS_OUT_OF_RANGE] = {
2922 		.key = ILLEGAL_REQUEST,
2923 		.asc = 0x21, /* LOGICAL BLOCK ADDRESS OUT OF RANGE */
2924 	},
2925 	[TCM_CHECK_CONDITION_UNIT_ATTENTION] = {
2926 		.key = UNIT_ATTENTION,
2927 	},
2928 	[TCM_CHECK_CONDITION_NOT_READY] = {
2929 		.key = NOT_READY,
2930 	},
2931 	[TCM_MISCOMPARE_VERIFY] = {
2932 		.key = MISCOMPARE,
2933 		.asc = 0x1d, /* MISCOMPARE DURING VERIFY OPERATION */
2934 		.ascq = 0x00,
2935 	},
2936 	[TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED] = {
2937 		.key = ABORTED_COMMAND,
2938 		.asc = 0x10,
2939 		.ascq = 0x01, /* LOGICAL BLOCK GUARD CHECK FAILED */
2940 		.add_sector_info = true,
2941 	},
2942 	[TCM_LOGICAL_BLOCK_APP_TAG_CHECK_FAILED] = {
2943 		.key = ABORTED_COMMAND,
2944 		.asc = 0x10,
2945 		.ascq = 0x02, /* LOGICAL BLOCK APPLICATION TAG CHECK FAILED */
2946 		.add_sector_info = true,
2947 	},
2948 	[TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED] = {
2949 		.key = ABORTED_COMMAND,
2950 		.asc = 0x10,
2951 		.ascq = 0x03, /* LOGICAL BLOCK REFERENCE TAG CHECK FAILED */
2952 		.add_sector_info = true,
2953 	},
2954 	[TCM_COPY_TARGET_DEVICE_NOT_REACHABLE] = {
2955 		.key = COPY_ABORTED,
2956 		.asc = 0x0d,
2957 		.ascq = 0x02, /* COPY TARGET DEVICE NOT REACHABLE */
2958 
2959 	},
2960 	[TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE] = {
2961 		/*
2962 		 * Returning ILLEGAL REQUEST would cause immediate IO errors on
2963 		 * Solaris initiators.  Returning NOT READY instead means the
2964 		 * operations will be retried a finite number of times and we
2965 		 * can survive intermittent errors.
2966 		 */
2967 		.key = NOT_READY,
2968 		.asc = 0x08, /* LOGICAL UNIT COMMUNICATION FAILURE */
2969 	},
2970 };
2971 
2972 static int translate_sense_reason(struct se_cmd *cmd, sense_reason_t reason)
2973 {
2974 	const struct sense_info *si;
2975 	u8 *buffer = cmd->sense_buffer;
2976 	int r = (__force int)reason;
2977 	u8 asc, ascq;
2978 	bool desc_format = target_sense_desc_format(cmd->se_dev);
2979 
2980 	if (r < ARRAY_SIZE(sense_info_table) && sense_info_table[r].key)
2981 		si = &sense_info_table[r];
2982 	else
2983 		si = &sense_info_table[(__force int)
2984 				       TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE];
2985 
2986 	if (reason == TCM_CHECK_CONDITION_UNIT_ATTENTION) {
2987 		core_scsi3_ua_for_check_condition(cmd, &asc, &ascq);
2988 		WARN_ON_ONCE(asc == 0);
2989 	} else if (si->asc == 0) {
2990 		WARN_ON_ONCE(cmd->scsi_asc == 0);
2991 		asc = cmd->scsi_asc;
2992 		ascq = cmd->scsi_ascq;
2993 	} else {
2994 		asc = si->asc;
2995 		ascq = si->ascq;
2996 	}
2997 
2998 	scsi_build_sense_buffer(desc_format, buffer, si->key, asc, ascq);
2999 	if (si->add_sector_info)
3000 		return scsi_set_sense_information(buffer,
3001 						  cmd->scsi_sense_length,
3002 						  cmd->bad_sector);
3003 
3004 	return 0;
3005 }
3006 
3007 int
3008 transport_send_check_condition_and_sense(struct se_cmd *cmd,
3009 		sense_reason_t reason, int from_transport)
3010 {
3011 	unsigned long flags;
3012 
3013 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3014 	if (cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION) {
3015 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3016 		return 0;
3017 	}
3018 	cmd->se_cmd_flags |= SCF_SENT_CHECK_CONDITION;
3019 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3020 
3021 	if (!from_transport) {
3022 		int rc;
3023 
3024 		cmd->se_cmd_flags |= SCF_EMULATED_TASK_SENSE;
3025 		cmd->scsi_status = SAM_STAT_CHECK_CONDITION;
3026 		cmd->scsi_sense_length  = TRANSPORT_SENSE_BUFFER;
3027 		rc = translate_sense_reason(cmd, reason);
3028 		if (rc)
3029 			return rc;
3030 	}
3031 
3032 	trace_target_cmd_complete(cmd);
3033 	return cmd->se_tfo->queue_status(cmd);
3034 }
3035 EXPORT_SYMBOL(transport_send_check_condition_and_sense);
3036 
3037 static int __transport_check_aborted_status(struct se_cmd *cmd, int send_status)
3038 	__releases(&cmd->t_state_lock)
3039 	__acquires(&cmd->t_state_lock)
3040 {
3041 	int ret;
3042 
3043 	assert_spin_locked(&cmd->t_state_lock);
3044 	WARN_ON_ONCE(!irqs_disabled());
3045 
3046 	if (!(cmd->transport_state & CMD_T_ABORTED))
3047 		return 0;
3048 	/*
3049 	 * If cmd has been aborted but either no status is to be sent or it has
3050 	 * already been sent, just return
3051 	 */
3052 	if (!send_status || !(cmd->se_cmd_flags & SCF_SEND_DELAYED_TAS)) {
3053 		if (send_status)
3054 			cmd->se_cmd_flags |= SCF_SEND_DELAYED_TAS;
3055 		return 1;
3056 	}
3057 
3058 	pr_debug("Sending delayed SAM_STAT_TASK_ABORTED status for CDB:"
3059 		" 0x%02x ITT: 0x%08llx\n", cmd->t_task_cdb[0], cmd->tag);
3060 
3061 	cmd->se_cmd_flags &= ~SCF_SEND_DELAYED_TAS;
3062 	cmd->scsi_status = SAM_STAT_TASK_ABORTED;
3063 	trace_target_cmd_complete(cmd);
3064 
3065 	spin_unlock_irq(&cmd->t_state_lock);
3066 	ret = cmd->se_tfo->queue_status(cmd);
3067 	if (ret)
3068 		transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
3069 	spin_lock_irq(&cmd->t_state_lock);
3070 
3071 	return 1;
3072 }
3073 
3074 int transport_check_aborted_status(struct se_cmd *cmd, int send_status)
3075 {
3076 	int ret;
3077 
3078 	spin_lock_irq(&cmd->t_state_lock);
3079 	ret = __transport_check_aborted_status(cmd, send_status);
3080 	spin_unlock_irq(&cmd->t_state_lock);
3081 
3082 	return ret;
3083 }
3084 EXPORT_SYMBOL(transport_check_aborted_status);
3085 
3086 void transport_send_task_abort(struct se_cmd *cmd)
3087 {
3088 	unsigned long flags;
3089 	int ret;
3090 
3091 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3092 	if (cmd->se_cmd_flags & (SCF_SENT_CHECK_CONDITION)) {
3093 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3094 		return;
3095 	}
3096 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3097 
3098 	/*
3099 	 * If there are still expected incoming fabric WRITEs, we wait
3100 	 * until until they have completed before sending a TASK_ABORTED
3101 	 * response.  This response with TASK_ABORTED status will be
3102 	 * queued back to fabric module by transport_check_aborted_status().
3103 	 */
3104 	if (cmd->data_direction == DMA_TO_DEVICE) {
3105 		if (cmd->se_tfo->write_pending_status(cmd) != 0) {
3106 			spin_lock_irqsave(&cmd->t_state_lock, flags);
3107 			if (cmd->se_cmd_flags & SCF_SEND_DELAYED_TAS) {
3108 				spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3109 				goto send_abort;
3110 			}
3111 			cmd->se_cmd_flags |= SCF_SEND_DELAYED_TAS;
3112 			spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3113 			return;
3114 		}
3115 	}
3116 send_abort:
3117 	cmd->scsi_status = SAM_STAT_TASK_ABORTED;
3118 
3119 	transport_lun_remove_cmd(cmd);
3120 
3121 	pr_debug("Setting SAM_STAT_TASK_ABORTED status for CDB: 0x%02x, ITT: 0x%08llx\n",
3122 		 cmd->t_task_cdb[0], cmd->tag);
3123 
3124 	trace_target_cmd_complete(cmd);
3125 	ret = cmd->se_tfo->queue_status(cmd);
3126 	if (ret)
3127 		transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
3128 }
3129 
3130 static void target_tmr_work(struct work_struct *work)
3131 {
3132 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
3133 	struct se_device *dev = cmd->se_dev;
3134 	struct se_tmr_req *tmr = cmd->se_tmr_req;
3135 	unsigned long flags;
3136 	int ret;
3137 
3138 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3139 	if (cmd->transport_state & CMD_T_ABORTED) {
3140 		tmr->response = TMR_FUNCTION_REJECTED;
3141 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3142 		goto check_stop;
3143 	}
3144 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3145 
3146 	switch (tmr->function) {
3147 	case TMR_ABORT_TASK:
3148 		core_tmr_abort_task(dev, tmr, cmd->se_sess);
3149 		break;
3150 	case TMR_ABORT_TASK_SET:
3151 	case TMR_CLEAR_ACA:
3152 	case TMR_CLEAR_TASK_SET:
3153 		tmr->response = TMR_TASK_MGMT_FUNCTION_NOT_SUPPORTED;
3154 		break;
3155 	case TMR_LUN_RESET:
3156 		ret = core_tmr_lun_reset(dev, tmr, NULL, NULL);
3157 		tmr->response = (!ret) ? TMR_FUNCTION_COMPLETE :
3158 					 TMR_FUNCTION_REJECTED;
3159 		if (tmr->response == TMR_FUNCTION_COMPLETE) {
3160 			target_ua_allocate_lun(cmd->se_sess->se_node_acl,
3161 					       cmd->orig_fe_lun, 0x29,
3162 					       ASCQ_29H_BUS_DEVICE_RESET_FUNCTION_OCCURRED);
3163 		}
3164 		break;
3165 	case TMR_TARGET_WARM_RESET:
3166 		tmr->response = TMR_FUNCTION_REJECTED;
3167 		break;
3168 	case TMR_TARGET_COLD_RESET:
3169 		tmr->response = TMR_FUNCTION_REJECTED;
3170 		break;
3171 	default:
3172 		pr_err("Uknown TMR function: 0x%02x.\n",
3173 				tmr->function);
3174 		tmr->response = TMR_FUNCTION_REJECTED;
3175 		break;
3176 	}
3177 
3178 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3179 	if (cmd->transport_state & CMD_T_ABORTED) {
3180 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3181 		goto check_stop;
3182 	}
3183 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3184 
3185 	cmd->se_tfo->queue_tm_rsp(cmd);
3186 
3187 check_stop:
3188 	transport_cmd_check_stop_to_fabric(cmd);
3189 }
3190 
3191 int transport_generic_handle_tmr(
3192 	struct se_cmd *cmd)
3193 {
3194 	unsigned long flags;
3195 	bool aborted = false;
3196 
3197 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3198 	if (cmd->transport_state & CMD_T_ABORTED) {
3199 		aborted = true;
3200 	} else {
3201 		cmd->t_state = TRANSPORT_ISTATE_PROCESSING;
3202 		cmd->transport_state |= CMD_T_ACTIVE;
3203 	}
3204 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3205 
3206 	if (aborted) {
3207 		pr_warn_ratelimited("handle_tmr caught CMD_T_ABORTED TMR %d"
3208 			"ref_tag: %llu tag: %llu\n", cmd->se_tmr_req->function,
3209 			cmd->se_tmr_req->ref_task_tag, cmd->tag);
3210 		transport_cmd_check_stop_to_fabric(cmd);
3211 		return 0;
3212 	}
3213 
3214 	INIT_WORK(&cmd->work, target_tmr_work);
3215 	queue_work(cmd->se_dev->tmr_wq, &cmd->work);
3216 	return 0;
3217 }
3218 EXPORT_SYMBOL(transport_generic_handle_tmr);
3219 
3220 bool
3221 target_check_wce(struct se_device *dev)
3222 {
3223 	bool wce = false;
3224 
3225 	if (dev->transport->get_write_cache)
3226 		wce = dev->transport->get_write_cache(dev);
3227 	else if (dev->dev_attrib.emulate_write_cache > 0)
3228 		wce = true;
3229 
3230 	return wce;
3231 }
3232 
3233 bool
3234 target_check_fua(struct se_device *dev)
3235 {
3236 	return target_check_wce(dev) && dev->dev_attrib.emulate_fua_write > 0;
3237 }
3238