xref: /linux/drivers/target/target_core_transport.c (revision 0883c2c06fb5bcf5b9e008270827e63c09a88c1e)
1 /*******************************************************************************
2  * Filename:  target_core_transport.c
3  *
4  * This file contains the Generic Target Engine Core.
5  *
6  * (c) Copyright 2002-2013 Datera, Inc.
7  *
8  * Nicholas A. Bellinger <nab@kernel.org>
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License as published by
12  * the Free Software Foundation; either version 2 of the License, or
13  * (at your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18  * GNU General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with this program; if not, write to the Free Software
22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
23  *
24  ******************************************************************************/
25 
26 #include <linux/net.h>
27 #include <linux/delay.h>
28 #include <linux/string.h>
29 #include <linux/timer.h>
30 #include <linux/slab.h>
31 #include <linux/spinlock.h>
32 #include <linux/kthread.h>
33 #include <linux/in.h>
34 #include <linux/cdrom.h>
35 #include <linux/module.h>
36 #include <linux/ratelimit.h>
37 #include <linux/vmalloc.h>
38 #include <asm/unaligned.h>
39 #include <net/sock.h>
40 #include <net/tcp.h>
41 #include <scsi/scsi_proto.h>
42 #include <scsi/scsi_common.h>
43 
44 #include <target/target_core_base.h>
45 #include <target/target_core_backend.h>
46 #include <target/target_core_fabric.h>
47 
48 #include "target_core_internal.h"
49 #include "target_core_alua.h"
50 #include "target_core_pr.h"
51 #include "target_core_ua.h"
52 
53 #define CREATE_TRACE_POINTS
54 #include <trace/events/target.h>
55 
56 static struct workqueue_struct *target_completion_wq;
57 static struct kmem_cache *se_sess_cache;
58 struct kmem_cache *se_ua_cache;
59 struct kmem_cache *t10_pr_reg_cache;
60 struct kmem_cache *t10_alua_lu_gp_cache;
61 struct kmem_cache *t10_alua_lu_gp_mem_cache;
62 struct kmem_cache *t10_alua_tg_pt_gp_cache;
63 struct kmem_cache *t10_alua_lba_map_cache;
64 struct kmem_cache *t10_alua_lba_map_mem_cache;
65 
66 static void transport_complete_task_attr(struct se_cmd *cmd);
67 static void transport_handle_queue_full(struct se_cmd *cmd,
68 		struct se_device *dev);
69 static int transport_put_cmd(struct se_cmd *cmd);
70 static void target_complete_ok_work(struct work_struct *work);
71 
72 int init_se_kmem_caches(void)
73 {
74 	se_sess_cache = kmem_cache_create("se_sess_cache",
75 			sizeof(struct se_session), __alignof__(struct se_session),
76 			0, NULL);
77 	if (!se_sess_cache) {
78 		pr_err("kmem_cache_create() for struct se_session"
79 				" failed\n");
80 		goto out;
81 	}
82 	se_ua_cache = kmem_cache_create("se_ua_cache",
83 			sizeof(struct se_ua), __alignof__(struct se_ua),
84 			0, NULL);
85 	if (!se_ua_cache) {
86 		pr_err("kmem_cache_create() for struct se_ua failed\n");
87 		goto out_free_sess_cache;
88 	}
89 	t10_pr_reg_cache = kmem_cache_create("t10_pr_reg_cache",
90 			sizeof(struct t10_pr_registration),
91 			__alignof__(struct t10_pr_registration), 0, NULL);
92 	if (!t10_pr_reg_cache) {
93 		pr_err("kmem_cache_create() for struct t10_pr_registration"
94 				" failed\n");
95 		goto out_free_ua_cache;
96 	}
97 	t10_alua_lu_gp_cache = kmem_cache_create("t10_alua_lu_gp_cache",
98 			sizeof(struct t10_alua_lu_gp), __alignof__(struct t10_alua_lu_gp),
99 			0, NULL);
100 	if (!t10_alua_lu_gp_cache) {
101 		pr_err("kmem_cache_create() for t10_alua_lu_gp_cache"
102 				" failed\n");
103 		goto out_free_pr_reg_cache;
104 	}
105 	t10_alua_lu_gp_mem_cache = kmem_cache_create("t10_alua_lu_gp_mem_cache",
106 			sizeof(struct t10_alua_lu_gp_member),
107 			__alignof__(struct t10_alua_lu_gp_member), 0, NULL);
108 	if (!t10_alua_lu_gp_mem_cache) {
109 		pr_err("kmem_cache_create() for t10_alua_lu_gp_mem_"
110 				"cache failed\n");
111 		goto out_free_lu_gp_cache;
112 	}
113 	t10_alua_tg_pt_gp_cache = kmem_cache_create("t10_alua_tg_pt_gp_cache",
114 			sizeof(struct t10_alua_tg_pt_gp),
115 			__alignof__(struct t10_alua_tg_pt_gp), 0, NULL);
116 	if (!t10_alua_tg_pt_gp_cache) {
117 		pr_err("kmem_cache_create() for t10_alua_tg_pt_gp_"
118 				"cache failed\n");
119 		goto out_free_lu_gp_mem_cache;
120 	}
121 	t10_alua_lba_map_cache = kmem_cache_create(
122 			"t10_alua_lba_map_cache",
123 			sizeof(struct t10_alua_lba_map),
124 			__alignof__(struct t10_alua_lba_map), 0, NULL);
125 	if (!t10_alua_lba_map_cache) {
126 		pr_err("kmem_cache_create() for t10_alua_lba_map_"
127 				"cache failed\n");
128 		goto out_free_tg_pt_gp_cache;
129 	}
130 	t10_alua_lba_map_mem_cache = kmem_cache_create(
131 			"t10_alua_lba_map_mem_cache",
132 			sizeof(struct t10_alua_lba_map_member),
133 			__alignof__(struct t10_alua_lba_map_member), 0, NULL);
134 	if (!t10_alua_lba_map_mem_cache) {
135 		pr_err("kmem_cache_create() for t10_alua_lba_map_mem_"
136 				"cache failed\n");
137 		goto out_free_lba_map_cache;
138 	}
139 
140 	target_completion_wq = alloc_workqueue("target_completion",
141 					       WQ_MEM_RECLAIM, 0);
142 	if (!target_completion_wq)
143 		goto out_free_lba_map_mem_cache;
144 
145 	return 0;
146 
147 out_free_lba_map_mem_cache:
148 	kmem_cache_destroy(t10_alua_lba_map_mem_cache);
149 out_free_lba_map_cache:
150 	kmem_cache_destroy(t10_alua_lba_map_cache);
151 out_free_tg_pt_gp_cache:
152 	kmem_cache_destroy(t10_alua_tg_pt_gp_cache);
153 out_free_lu_gp_mem_cache:
154 	kmem_cache_destroy(t10_alua_lu_gp_mem_cache);
155 out_free_lu_gp_cache:
156 	kmem_cache_destroy(t10_alua_lu_gp_cache);
157 out_free_pr_reg_cache:
158 	kmem_cache_destroy(t10_pr_reg_cache);
159 out_free_ua_cache:
160 	kmem_cache_destroy(se_ua_cache);
161 out_free_sess_cache:
162 	kmem_cache_destroy(se_sess_cache);
163 out:
164 	return -ENOMEM;
165 }
166 
167 void release_se_kmem_caches(void)
168 {
169 	destroy_workqueue(target_completion_wq);
170 	kmem_cache_destroy(se_sess_cache);
171 	kmem_cache_destroy(se_ua_cache);
172 	kmem_cache_destroy(t10_pr_reg_cache);
173 	kmem_cache_destroy(t10_alua_lu_gp_cache);
174 	kmem_cache_destroy(t10_alua_lu_gp_mem_cache);
175 	kmem_cache_destroy(t10_alua_tg_pt_gp_cache);
176 	kmem_cache_destroy(t10_alua_lba_map_cache);
177 	kmem_cache_destroy(t10_alua_lba_map_mem_cache);
178 }
179 
180 /* This code ensures unique mib indexes are handed out. */
181 static DEFINE_SPINLOCK(scsi_mib_index_lock);
182 static u32 scsi_mib_index[SCSI_INDEX_TYPE_MAX];
183 
184 /*
185  * Allocate a new row index for the entry type specified
186  */
187 u32 scsi_get_new_index(scsi_index_t type)
188 {
189 	u32 new_index;
190 
191 	BUG_ON((type < 0) || (type >= SCSI_INDEX_TYPE_MAX));
192 
193 	spin_lock(&scsi_mib_index_lock);
194 	new_index = ++scsi_mib_index[type];
195 	spin_unlock(&scsi_mib_index_lock);
196 
197 	return new_index;
198 }
199 
200 void transport_subsystem_check_init(void)
201 {
202 	int ret;
203 	static int sub_api_initialized;
204 
205 	if (sub_api_initialized)
206 		return;
207 
208 	ret = request_module("target_core_iblock");
209 	if (ret != 0)
210 		pr_err("Unable to load target_core_iblock\n");
211 
212 	ret = request_module("target_core_file");
213 	if (ret != 0)
214 		pr_err("Unable to load target_core_file\n");
215 
216 	ret = request_module("target_core_pscsi");
217 	if (ret != 0)
218 		pr_err("Unable to load target_core_pscsi\n");
219 
220 	ret = request_module("target_core_user");
221 	if (ret != 0)
222 		pr_err("Unable to load target_core_user\n");
223 
224 	sub_api_initialized = 1;
225 }
226 
227 struct se_session *transport_init_session(enum target_prot_op sup_prot_ops)
228 {
229 	struct se_session *se_sess;
230 
231 	se_sess = kmem_cache_zalloc(se_sess_cache, GFP_KERNEL);
232 	if (!se_sess) {
233 		pr_err("Unable to allocate struct se_session from"
234 				" se_sess_cache\n");
235 		return ERR_PTR(-ENOMEM);
236 	}
237 	INIT_LIST_HEAD(&se_sess->sess_list);
238 	INIT_LIST_HEAD(&se_sess->sess_acl_list);
239 	INIT_LIST_HEAD(&se_sess->sess_cmd_list);
240 	INIT_LIST_HEAD(&se_sess->sess_wait_list);
241 	spin_lock_init(&se_sess->sess_cmd_lock);
242 	se_sess->sup_prot_ops = sup_prot_ops;
243 
244 	return se_sess;
245 }
246 EXPORT_SYMBOL(transport_init_session);
247 
248 int transport_alloc_session_tags(struct se_session *se_sess,
249 			         unsigned int tag_num, unsigned int tag_size)
250 {
251 	int rc;
252 
253 	se_sess->sess_cmd_map = kzalloc(tag_num * tag_size,
254 					GFP_KERNEL | __GFP_NOWARN | __GFP_REPEAT);
255 	if (!se_sess->sess_cmd_map) {
256 		se_sess->sess_cmd_map = vzalloc(tag_num * tag_size);
257 		if (!se_sess->sess_cmd_map) {
258 			pr_err("Unable to allocate se_sess->sess_cmd_map\n");
259 			return -ENOMEM;
260 		}
261 	}
262 
263 	rc = percpu_ida_init(&se_sess->sess_tag_pool, tag_num);
264 	if (rc < 0) {
265 		pr_err("Unable to init se_sess->sess_tag_pool,"
266 			" tag_num: %u\n", tag_num);
267 		kvfree(se_sess->sess_cmd_map);
268 		se_sess->sess_cmd_map = NULL;
269 		return -ENOMEM;
270 	}
271 
272 	return 0;
273 }
274 EXPORT_SYMBOL(transport_alloc_session_tags);
275 
276 struct se_session *transport_init_session_tags(unsigned int tag_num,
277 					       unsigned int tag_size,
278 					       enum target_prot_op sup_prot_ops)
279 {
280 	struct se_session *se_sess;
281 	int rc;
282 
283 	if (tag_num != 0 && !tag_size) {
284 		pr_err("init_session_tags called with percpu-ida tag_num:"
285 		       " %u, but zero tag_size\n", tag_num);
286 		return ERR_PTR(-EINVAL);
287 	}
288 	if (!tag_num && tag_size) {
289 		pr_err("init_session_tags called with percpu-ida tag_size:"
290 		       " %u, but zero tag_num\n", tag_size);
291 		return ERR_PTR(-EINVAL);
292 	}
293 
294 	se_sess = transport_init_session(sup_prot_ops);
295 	if (IS_ERR(se_sess))
296 		return se_sess;
297 
298 	rc = transport_alloc_session_tags(se_sess, tag_num, tag_size);
299 	if (rc < 0) {
300 		transport_free_session(se_sess);
301 		return ERR_PTR(-ENOMEM);
302 	}
303 
304 	return se_sess;
305 }
306 EXPORT_SYMBOL(transport_init_session_tags);
307 
308 /*
309  * Called with spin_lock_irqsave(&struct se_portal_group->session_lock called.
310  */
311 void __transport_register_session(
312 	struct se_portal_group *se_tpg,
313 	struct se_node_acl *se_nacl,
314 	struct se_session *se_sess,
315 	void *fabric_sess_ptr)
316 {
317 	const struct target_core_fabric_ops *tfo = se_tpg->se_tpg_tfo;
318 	unsigned char buf[PR_REG_ISID_LEN];
319 
320 	se_sess->se_tpg = se_tpg;
321 	se_sess->fabric_sess_ptr = fabric_sess_ptr;
322 	/*
323 	 * Used by struct se_node_acl's under ConfigFS to locate active se_session-t
324 	 *
325 	 * Only set for struct se_session's that will actually be moving I/O.
326 	 * eg: *NOT* discovery sessions.
327 	 */
328 	if (se_nacl) {
329 		/*
330 		 *
331 		 * Determine if fabric allows for T10-PI feature bits exposed to
332 		 * initiators for device backends with !dev->dev_attrib.pi_prot_type.
333 		 *
334 		 * If so, then always save prot_type on a per se_node_acl node
335 		 * basis and re-instate the previous sess_prot_type to avoid
336 		 * disabling PI from below any previously initiator side
337 		 * registered LUNs.
338 		 */
339 		if (se_nacl->saved_prot_type)
340 			se_sess->sess_prot_type = se_nacl->saved_prot_type;
341 		else if (tfo->tpg_check_prot_fabric_only)
342 			se_sess->sess_prot_type = se_nacl->saved_prot_type =
343 					tfo->tpg_check_prot_fabric_only(se_tpg);
344 		/*
345 		 * If the fabric module supports an ISID based TransportID,
346 		 * save this value in binary from the fabric I_T Nexus now.
347 		 */
348 		if (se_tpg->se_tpg_tfo->sess_get_initiator_sid != NULL) {
349 			memset(&buf[0], 0, PR_REG_ISID_LEN);
350 			se_tpg->se_tpg_tfo->sess_get_initiator_sid(se_sess,
351 					&buf[0], PR_REG_ISID_LEN);
352 			se_sess->sess_bin_isid = get_unaligned_be64(&buf[0]);
353 		}
354 
355 		spin_lock_irq(&se_nacl->nacl_sess_lock);
356 		/*
357 		 * The se_nacl->nacl_sess pointer will be set to the
358 		 * last active I_T Nexus for each struct se_node_acl.
359 		 */
360 		se_nacl->nacl_sess = se_sess;
361 
362 		list_add_tail(&se_sess->sess_acl_list,
363 			      &se_nacl->acl_sess_list);
364 		spin_unlock_irq(&se_nacl->nacl_sess_lock);
365 	}
366 	list_add_tail(&se_sess->sess_list, &se_tpg->tpg_sess_list);
367 
368 	pr_debug("TARGET_CORE[%s]: Registered fabric_sess_ptr: %p\n",
369 		se_tpg->se_tpg_tfo->get_fabric_name(), se_sess->fabric_sess_ptr);
370 }
371 EXPORT_SYMBOL(__transport_register_session);
372 
373 void transport_register_session(
374 	struct se_portal_group *se_tpg,
375 	struct se_node_acl *se_nacl,
376 	struct se_session *se_sess,
377 	void *fabric_sess_ptr)
378 {
379 	unsigned long flags;
380 
381 	spin_lock_irqsave(&se_tpg->session_lock, flags);
382 	__transport_register_session(se_tpg, se_nacl, se_sess, fabric_sess_ptr);
383 	spin_unlock_irqrestore(&se_tpg->session_lock, flags);
384 }
385 EXPORT_SYMBOL(transport_register_session);
386 
387 struct se_session *
388 target_alloc_session(struct se_portal_group *tpg,
389 		     unsigned int tag_num, unsigned int tag_size,
390 		     enum target_prot_op prot_op,
391 		     const char *initiatorname, void *private,
392 		     int (*callback)(struct se_portal_group *,
393 				     struct se_session *, void *))
394 {
395 	struct se_session *sess;
396 
397 	/*
398 	 * If the fabric driver is using percpu-ida based pre allocation
399 	 * of I/O descriptor tags, go ahead and perform that setup now..
400 	 */
401 	if (tag_num != 0)
402 		sess = transport_init_session_tags(tag_num, tag_size, prot_op);
403 	else
404 		sess = transport_init_session(prot_op);
405 
406 	if (IS_ERR(sess))
407 		return sess;
408 
409 	sess->se_node_acl = core_tpg_check_initiator_node_acl(tpg,
410 					(unsigned char *)initiatorname);
411 	if (!sess->se_node_acl) {
412 		transport_free_session(sess);
413 		return ERR_PTR(-EACCES);
414 	}
415 	/*
416 	 * Go ahead and perform any remaining fabric setup that is
417 	 * required before transport_register_session().
418 	 */
419 	if (callback != NULL) {
420 		int rc = callback(tpg, sess, private);
421 		if (rc) {
422 			transport_free_session(sess);
423 			return ERR_PTR(rc);
424 		}
425 	}
426 
427 	transport_register_session(tpg, sess->se_node_acl, sess, private);
428 	return sess;
429 }
430 EXPORT_SYMBOL(target_alloc_session);
431 
432 ssize_t target_show_dynamic_sessions(struct se_portal_group *se_tpg, char *page)
433 {
434 	struct se_session *se_sess;
435 	ssize_t len = 0;
436 
437 	spin_lock_bh(&se_tpg->session_lock);
438 	list_for_each_entry(se_sess, &se_tpg->tpg_sess_list, sess_list) {
439 		if (!se_sess->se_node_acl)
440 			continue;
441 		if (!se_sess->se_node_acl->dynamic_node_acl)
442 			continue;
443 		if (strlen(se_sess->se_node_acl->initiatorname) + 1 + len > PAGE_SIZE)
444 			break;
445 
446 		len += snprintf(page + len, PAGE_SIZE - len, "%s\n",
447 				se_sess->se_node_acl->initiatorname);
448 		len += 1; /* Include NULL terminator */
449 	}
450 	spin_unlock_bh(&se_tpg->session_lock);
451 
452 	return len;
453 }
454 EXPORT_SYMBOL(target_show_dynamic_sessions);
455 
456 static void target_complete_nacl(struct kref *kref)
457 {
458 	struct se_node_acl *nacl = container_of(kref,
459 				struct se_node_acl, acl_kref);
460 
461 	complete(&nacl->acl_free_comp);
462 }
463 
464 void target_put_nacl(struct se_node_acl *nacl)
465 {
466 	kref_put(&nacl->acl_kref, target_complete_nacl);
467 }
468 EXPORT_SYMBOL(target_put_nacl);
469 
470 void transport_deregister_session_configfs(struct se_session *se_sess)
471 {
472 	struct se_node_acl *se_nacl;
473 	unsigned long flags;
474 	/*
475 	 * Used by struct se_node_acl's under ConfigFS to locate active struct se_session
476 	 */
477 	se_nacl = se_sess->se_node_acl;
478 	if (se_nacl) {
479 		spin_lock_irqsave(&se_nacl->nacl_sess_lock, flags);
480 		if (!list_empty(&se_sess->sess_acl_list))
481 			list_del_init(&se_sess->sess_acl_list);
482 		/*
483 		 * If the session list is empty, then clear the pointer.
484 		 * Otherwise, set the struct se_session pointer from the tail
485 		 * element of the per struct se_node_acl active session list.
486 		 */
487 		if (list_empty(&se_nacl->acl_sess_list))
488 			se_nacl->nacl_sess = NULL;
489 		else {
490 			se_nacl->nacl_sess = container_of(
491 					se_nacl->acl_sess_list.prev,
492 					struct se_session, sess_acl_list);
493 		}
494 		spin_unlock_irqrestore(&se_nacl->nacl_sess_lock, flags);
495 	}
496 }
497 EXPORT_SYMBOL(transport_deregister_session_configfs);
498 
499 void transport_free_session(struct se_session *se_sess)
500 {
501 	struct se_node_acl *se_nacl = se_sess->se_node_acl;
502 	/*
503 	 * Drop the se_node_acl->nacl_kref obtained from within
504 	 * core_tpg_get_initiator_node_acl().
505 	 */
506 	if (se_nacl) {
507 		se_sess->se_node_acl = NULL;
508 		target_put_nacl(se_nacl);
509 	}
510 	if (se_sess->sess_cmd_map) {
511 		percpu_ida_destroy(&se_sess->sess_tag_pool);
512 		kvfree(se_sess->sess_cmd_map);
513 	}
514 	kmem_cache_free(se_sess_cache, se_sess);
515 }
516 EXPORT_SYMBOL(transport_free_session);
517 
518 void transport_deregister_session(struct se_session *se_sess)
519 {
520 	struct se_portal_group *se_tpg = se_sess->se_tpg;
521 	const struct target_core_fabric_ops *se_tfo;
522 	struct se_node_acl *se_nacl;
523 	unsigned long flags;
524 	bool drop_nacl = false;
525 
526 	if (!se_tpg) {
527 		transport_free_session(se_sess);
528 		return;
529 	}
530 	se_tfo = se_tpg->se_tpg_tfo;
531 
532 	spin_lock_irqsave(&se_tpg->session_lock, flags);
533 	list_del(&se_sess->sess_list);
534 	se_sess->se_tpg = NULL;
535 	se_sess->fabric_sess_ptr = NULL;
536 	spin_unlock_irqrestore(&se_tpg->session_lock, flags);
537 
538 	/*
539 	 * Determine if we need to do extra work for this initiator node's
540 	 * struct se_node_acl if it had been previously dynamically generated.
541 	 */
542 	se_nacl = se_sess->se_node_acl;
543 
544 	mutex_lock(&se_tpg->acl_node_mutex);
545 	if (se_nacl && se_nacl->dynamic_node_acl) {
546 		if (!se_tfo->tpg_check_demo_mode_cache(se_tpg)) {
547 			list_del(&se_nacl->acl_list);
548 			drop_nacl = true;
549 		}
550 	}
551 	mutex_unlock(&se_tpg->acl_node_mutex);
552 
553 	if (drop_nacl) {
554 		core_tpg_wait_for_nacl_pr_ref(se_nacl);
555 		core_free_device_list_for_node(se_nacl, se_tpg);
556 		se_sess->se_node_acl = NULL;
557 		kfree(se_nacl);
558 	}
559 	pr_debug("TARGET_CORE[%s]: Deregistered fabric_sess\n",
560 		se_tpg->se_tpg_tfo->get_fabric_name());
561 	/*
562 	 * If last kref is dropping now for an explicit NodeACL, awake sleeping
563 	 * ->acl_free_comp caller to wakeup configfs se_node_acl->acl_group
564 	 * removal context from within transport_free_session() code.
565 	 */
566 
567 	transport_free_session(se_sess);
568 }
569 EXPORT_SYMBOL(transport_deregister_session);
570 
571 static void target_remove_from_state_list(struct se_cmd *cmd)
572 {
573 	struct se_device *dev = cmd->se_dev;
574 	unsigned long flags;
575 
576 	if (!dev)
577 		return;
578 
579 	if (cmd->transport_state & CMD_T_BUSY)
580 		return;
581 
582 	spin_lock_irqsave(&dev->execute_task_lock, flags);
583 	if (cmd->state_active) {
584 		list_del(&cmd->state_list);
585 		cmd->state_active = false;
586 	}
587 	spin_unlock_irqrestore(&dev->execute_task_lock, flags);
588 }
589 
590 static int transport_cmd_check_stop(struct se_cmd *cmd, bool remove_from_lists,
591 				    bool write_pending)
592 {
593 	unsigned long flags;
594 
595 	if (remove_from_lists) {
596 		target_remove_from_state_list(cmd);
597 
598 		/*
599 		 * Clear struct se_cmd->se_lun before the handoff to FE.
600 		 */
601 		cmd->se_lun = NULL;
602 	}
603 
604 	spin_lock_irqsave(&cmd->t_state_lock, flags);
605 	if (write_pending)
606 		cmd->t_state = TRANSPORT_WRITE_PENDING;
607 
608 	/*
609 	 * Determine if frontend context caller is requesting the stopping of
610 	 * this command for frontend exceptions.
611 	 */
612 	if (cmd->transport_state & CMD_T_STOP) {
613 		pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08llx\n",
614 			__func__, __LINE__, cmd->tag);
615 
616 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
617 
618 		complete_all(&cmd->t_transport_stop_comp);
619 		return 1;
620 	}
621 
622 	cmd->transport_state &= ~CMD_T_ACTIVE;
623 	if (remove_from_lists) {
624 		/*
625 		 * Some fabric modules like tcm_loop can release
626 		 * their internally allocated I/O reference now and
627 		 * struct se_cmd now.
628 		 *
629 		 * Fabric modules are expected to return '1' here if the
630 		 * se_cmd being passed is released at this point,
631 		 * or zero if not being released.
632 		 */
633 		if (cmd->se_tfo->check_stop_free != NULL) {
634 			spin_unlock_irqrestore(&cmd->t_state_lock, flags);
635 			return cmd->se_tfo->check_stop_free(cmd);
636 		}
637 	}
638 
639 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
640 	return 0;
641 }
642 
643 static int transport_cmd_check_stop_to_fabric(struct se_cmd *cmd)
644 {
645 	return transport_cmd_check_stop(cmd, true, false);
646 }
647 
648 static void transport_lun_remove_cmd(struct se_cmd *cmd)
649 {
650 	struct se_lun *lun = cmd->se_lun;
651 
652 	if (!lun)
653 		return;
654 
655 	if (cmpxchg(&cmd->lun_ref_active, true, false))
656 		percpu_ref_put(&lun->lun_ref);
657 }
658 
659 void transport_cmd_finish_abort(struct se_cmd *cmd, int remove)
660 {
661 	bool ack_kref = (cmd->se_cmd_flags & SCF_ACK_KREF);
662 
663 	if (cmd->se_cmd_flags & SCF_SE_LUN_CMD)
664 		transport_lun_remove_cmd(cmd);
665 	/*
666 	 * Allow the fabric driver to unmap any resources before
667 	 * releasing the descriptor via TFO->release_cmd()
668 	 */
669 	if (remove)
670 		cmd->se_tfo->aborted_task(cmd);
671 
672 	if (transport_cmd_check_stop_to_fabric(cmd))
673 		return;
674 	if (remove && ack_kref)
675 		transport_put_cmd(cmd);
676 }
677 
678 static void target_complete_failure_work(struct work_struct *work)
679 {
680 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
681 
682 	transport_generic_request_failure(cmd,
683 			TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE);
684 }
685 
686 /*
687  * Used when asking transport to copy Sense Data from the underlying
688  * Linux/SCSI struct scsi_cmnd
689  */
690 static unsigned char *transport_get_sense_buffer(struct se_cmd *cmd)
691 {
692 	struct se_device *dev = cmd->se_dev;
693 
694 	WARN_ON(!cmd->se_lun);
695 
696 	if (!dev)
697 		return NULL;
698 
699 	if (cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION)
700 		return NULL;
701 
702 	cmd->scsi_sense_length = TRANSPORT_SENSE_BUFFER;
703 
704 	pr_debug("HBA_[%u]_PLUG[%s]: Requesting sense for SAM STATUS: 0x%02x\n",
705 		dev->se_hba->hba_id, dev->transport->name, cmd->scsi_status);
706 	return cmd->sense_buffer;
707 }
708 
709 void target_complete_cmd(struct se_cmd *cmd, u8 scsi_status)
710 {
711 	struct se_device *dev = cmd->se_dev;
712 	int success = scsi_status == GOOD;
713 	unsigned long flags;
714 
715 	cmd->scsi_status = scsi_status;
716 
717 
718 	spin_lock_irqsave(&cmd->t_state_lock, flags);
719 	cmd->transport_state &= ~CMD_T_BUSY;
720 
721 	if (dev && dev->transport->transport_complete) {
722 		dev->transport->transport_complete(cmd,
723 				cmd->t_data_sg,
724 				transport_get_sense_buffer(cmd));
725 		if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE)
726 			success = 1;
727 	}
728 
729 	/*
730 	 * Check for case where an explicit ABORT_TASK has been received
731 	 * and transport_wait_for_tasks() will be waiting for completion..
732 	 */
733 	if (cmd->transport_state & CMD_T_ABORTED ||
734 	    cmd->transport_state & CMD_T_STOP) {
735 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
736 		complete_all(&cmd->t_transport_stop_comp);
737 		return;
738 	} else if (!success) {
739 		INIT_WORK(&cmd->work, target_complete_failure_work);
740 	} else {
741 		INIT_WORK(&cmd->work, target_complete_ok_work);
742 	}
743 
744 	cmd->t_state = TRANSPORT_COMPLETE;
745 	cmd->transport_state |= (CMD_T_COMPLETE | CMD_T_ACTIVE);
746 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
747 
748 	if (cmd->se_cmd_flags & SCF_USE_CPUID)
749 		queue_work_on(cmd->cpuid, target_completion_wq, &cmd->work);
750 	else
751 		queue_work(target_completion_wq, &cmd->work);
752 }
753 EXPORT_SYMBOL(target_complete_cmd);
754 
755 void target_complete_cmd_with_length(struct se_cmd *cmd, u8 scsi_status, int length)
756 {
757 	if (scsi_status == SAM_STAT_GOOD && length < cmd->data_length) {
758 		if (cmd->se_cmd_flags & SCF_UNDERFLOW_BIT) {
759 			cmd->residual_count += cmd->data_length - length;
760 		} else {
761 			cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
762 			cmd->residual_count = cmd->data_length - length;
763 		}
764 
765 		cmd->data_length = length;
766 	}
767 
768 	target_complete_cmd(cmd, scsi_status);
769 }
770 EXPORT_SYMBOL(target_complete_cmd_with_length);
771 
772 static void target_add_to_state_list(struct se_cmd *cmd)
773 {
774 	struct se_device *dev = cmd->se_dev;
775 	unsigned long flags;
776 
777 	spin_lock_irqsave(&dev->execute_task_lock, flags);
778 	if (!cmd->state_active) {
779 		list_add_tail(&cmd->state_list, &dev->state_list);
780 		cmd->state_active = true;
781 	}
782 	spin_unlock_irqrestore(&dev->execute_task_lock, flags);
783 }
784 
785 /*
786  * Handle QUEUE_FULL / -EAGAIN and -ENOMEM status
787  */
788 static void transport_write_pending_qf(struct se_cmd *cmd);
789 static void transport_complete_qf(struct se_cmd *cmd);
790 
791 void target_qf_do_work(struct work_struct *work)
792 {
793 	struct se_device *dev = container_of(work, struct se_device,
794 					qf_work_queue);
795 	LIST_HEAD(qf_cmd_list);
796 	struct se_cmd *cmd, *cmd_tmp;
797 
798 	spin_lock_irq(&dev->qf_cmd_lock);
799 	list_splice_init(&dev->qf_cmd_list, &qf_cmd_list);
800 	spin_unlock_irq(&dev->qf_cmd_lock);
801 
802 	list_for_each_entry_safe(cmd, cmd_tmp, &qf_cmd_list, se_qf_node) {
803 		list_del(&cmd->se_qf_node);
804 		atomic_dec_mb(&dev->dev_qf_count);
805 
806 		pr_debug("Processing %s cmd: %p QUEUE_FULL in work queue"
807 			" context: %s\n", cmd->se_tfo->get_fabric_name(), cmd,
808 			(cmd->t_state == TRANSPORT_COMPLETE_QF_OK) ? "COMPLETE_OK" :
809 			(cmd->t_state == TRANSPORT_COMPLETE_QF_WP) ? "WRITE_PENDING"
810 			: "UNKNOWN");
811 
812 		if (cmd->t_state == TRANSPORT_COMPLETE_QF_WP)
813 			transport_write_pending_qf(cmd);
814 		else if (cmd->t_state == TRANSPORT_COMPLETE_QF_OK)
815 			transport_complete_qf(cmd);
816 	}
817 }
818 
819 unsigned char *transport_dump_cmd_direction(struct se_cmd *cmd)
820 {
821 	switch (cmd->data_direction) {
822 	case DMA_NONE:
823 		return "NONE";
824 	case DMA_FROM_DEVICE:
825 		return "READ";
826 	case DMA_TO_DEVICE:
827 		return "WRITE";
828 	case DMA_BIDIRECTIONAL:
829 		return "BIDI";
830 	default:
831 		break;
832 	}
833 
834 	return "UNKNOWN";
835 }
836 
837 void transport_dump_dev_state(
838 	struct se_device *dev,
839 	char *b,
840 	int *bl)
841 {
842 	*bl += sprintf(b + *bl, "Status: ");
843 	if (dev->export_count)
844 		*bl += sprintf(b + *bl, "ACTIVATED");
845 	else
846 		*bl += sprintf(b + *bl, "DEACTIVATED");
847 
848 	*bl += sprintf(b + *bl, "  Max Queue Depth: %d", dev->queue_depth);
849 	*bl += sprintf(b + *bl, "  SectorSize: %u  HwMaxSectors: %u\n",
850 		dev->dev_attrib.block_size,
851 		dev->dev_attrib.hw_max_sectors);
852 	*bl += sprintf(b + *bl, "        ");
853 }
854 
855 void transport_dump_vpd_proto_id(
856 	struct t10_vpd *vpd,
857 	unsigned char *p_buf,
858 	int p_buf_len)
859 {
860 	unsigned char buf[VPD_TMP_BUF_SIZE];
861 	int len;
862 
863 	memset(buf, 0, VPD_TMP_BUF_SIZE);
864 	len = sprintf(buf, "T10 VPD Protocol Identifier: ");
865 
866 	switch (vpd->protocol_identifier) {
867 	case 0x00:
868 		sprintf(buf+len, "Fibre Channel\n");
869 		break;
870 	case 0x10:
871 		sprintf(buf+len, "Parallel SCSI\n");
872 		break;
873 	case 0x20:
874 		sprintf(buf+len, "SSA\n");
875 		break;
876 	case 0x30:
877 		sprintf(buf+len, "IEEE 1394\n");
878 		break;
879 	case 0x40:
880 		sprintf(buf+len, "SCSI Remote Direct Memory Access"
881 				" Protocol\n");
882 		break;
883 	case 0x50:
884 		sprintf(buf+len, "Internet SCSI (iSCSI)\n");
885 		break;
886 	case 0x60:
887 		sprintf(buf+len, "SAS Serial SCSI Protocol\n");
888 		break;
889 	case 0x70:
890 		sprintf(buf+len, "Automation/Drive Interface Transport"
891 				" Protocol\n");
892 		break;
893 	case 0x80:
894 		sprintf(buf+len, "AT Attachment Interface ATA/ATAPI\n");
895 		break;
896 	default:
897 		sprintf(buf+len, "Unknown 0x%02x\n",
898 				vpd->protocol_identifier);
899 		break;
900 	}
901 
902 	if (p_buf)
903 		strncpy(p_buf, buf, p_buf_len);
904 	else
905 		pr_debug("%s", buf);
906 }
907 
908 void
909 transport_set_vpd_proto_id(struct t10_vpd *vpd, unsigned char *page_83)
910 {
911 	/*
912 	 * Check if the Protocol Identifier Valid (PIV) bit is set..
913 	 *
914 	 * from spc3r23.pdf section 7.5.1
915 	 */
916 	 if (page_83[1] & 0x80) {
917 		vpd->protocol_identifier = (page_83[0] & 0xf0);
918 		vpd->protocol_identifier_set = 1;
919 		transport_dump_vpd_proto_id(vpd, NULL, 0);
920 	}
921 }
922 EXPORT_SYMBOL(transport_set_vpd_proto_id);
923 
924 int transport_dump_vpd_assoc(
925 	struct t10_vpd *vpd,
926 	unsigned char *p_buf,
927 	int p_buf_len)
928 {
929 	unsigned char buf[VPD_TMP_BUF_SIZE];
930 	int ret = 0;
931 	int len;
932 
933 	memset(buf, 0, VPD_TMP_BUF_SIZE);
934 	len = sprintf(buf, "T10 VPD Identifier Association: ");
935 
936 	switch (vpd->association) {
937 	case 0x00:
938 		sprintf(buf+len, "addressed logical unit\n");
939 		break;
940 	case 0x10:
941 		sprintf(buf+len, "target port\n");
942 		break;
943 	case 0x20:
944 		sprintf(buf+len, "SCSI target device\n");
945 		break;
946 	default:
947 		sprintf(buf+len, "Unknown 0x%02x\n", vpd->association);
948 		ret = -EINVAL;
949 		break;
950 	}
951 
952 	if (p_buf)
953 		strncpy(p_buf, buf, p_buf_len);
954 	else
955 		pr_debug("%s", buf);
956 
957 	return ret;
958 }
959 
960 int transport_set_vpd_assoc(struct t10_vpd *vpd, unsigned char *page_83)
961 {
962 	/*
963 	 * The VPD identification association..
964 	 *
965 	 * from spc3r23.pdf Section 7.6.3.1 Table 297
966 	 */
967 	vpd->association = (page_83[1] & 0x30);
968 	return transport_dump_vpd_assoc(vpd, NULL, 0);
969 }
970 EXPORT_SYMBOL(transport_set_vpd_assoc);
971 
972 int transport_dump_vpd_ident_type(
973 	struct t10_vpd *vpd,
974 	unsigned char *p_buf,
975 	int p_buf_len)
976 {
977 	unsigned char buf[VPD_TMP_BUF_SIZE];
978 	int ret = 0;
979 	int len;
980 
981 	memset(buf, 0, VPD_TMP_BUF_SIZE);
982 	len = sprintf(buf, "T10 VPD Identifier Type: ");
983 
984 	switch (vpd->device_identifier_type) {
985 	case 0x00:
986 		sprintf(buf+len, "Vendor specific\n");
987 		break;
988 	case 0x01:
989 		sprintf(buf+len, "T10 Vendor ID based\n");
990 		break;
991 	case 0x02:
992 		sprintf(buf+len, "EUI-64 based\n");
993 		break;
994 	case 0x03:
995 		sprintf(buf+len, "NAA\n");
996 		break;
997 	case 0x04:
998 		sprintf(buf+len, "Relative target port identifier\n");
999 		break;
1000 	case 0x08:
1001 		sprintf(buf+len, "SCSI name string\n");
1002 		break;
1003 	default:
1004 		sprintf(buf+len, "Unsupported: 0x%02x\n",
1005 				vpd->device_identifier_type);
1006 		ret = -EINVAL;
1007 		break;
1008 	}
1009 
1010 	if (p_buf) {
1011 		if (p_buf_len < strlen(buf)+1)
1012 			return -EINVAL;
1013 		strncpy(p_buf, buf, p_buf_len);
1014 	} else {
1015 		pr_debug("%s", buf);
1016 	}
1017 
1018 	return ret;
1019 }
1020 
1021 int transport_set_vpd_ident_type(struct t10_vpd *vpd, unsigned char *page_83)
1022 {
1023 	/*
1024 	 * The VPD identifier type..
1025 	 *
1026 	 * from spc3r23.pdf Section 7.6.3.1 Table 298
1027 	 */
1028 	vpd->device_identifier_type = (page_83[1] & 0x0f);
1029 	return transport_dump_vpd_ident_type(vpd, NULL, 0);
1030 }
1031 EXPORT_SYMBOL(transport_set_vpd_ident_type);
1032 
1033 int transport_dump_vpd_ident(
1034 	struct t10_vpd *vpd,
1035 	unsigned char *p_buf,
1036 	int p_buf_len)
1037 {
1038 	unsigned char buf[VPD_TMP_BUF_SIZE];
1039 	int ret = 0;
1040 
1041 	memset(buf, 0, VPD_TMP_BUF_SIZE);
1042 
1043 	switch (vpd->device_identifier_code_set) {
1044 	case 0x01: /* Binary */
1045 		snprintf(buf, sizeof(buf),
1046 			"T10 VPD Binary Device Identifier: %s\n",
1047 			&vpd->device_identifier[0]);
1048 		break;
1049 	case 0x02: /* ASCII */
1050 		snprintf(buf, sizeof(buf),
1051 			"T10 VPD ASCII Device Identifier: %s\n",
1052 			&vpd->device_identifier[0]);
1053 		break;
1054 	case 0x03: /* UTF-8 */
1055 		snprintf(buf, sizeof(buf),
1056 			"T10 VPD UTF-8 Device Identifier: %s\n",
1057 			&vpd->device_identifier[0]);
1058 		break;
1059 	default:
1060 		sprintf(buf, "T10 VPD Device Identifier encoding unsupported:"
1061 			" 0x%02x", vpd->device_identifier_code_set);
1062 		ret = -EINVAL;
1063 		break;
1064 	}
1065 
1066 	if (p_buf)
1067 		strncpy(p_buf, buf, p_buf_len);
1068 	else
1069 		pr_debug("%s", buf);
1070 
1071 	return ret;
1072 }
1073 
1074 int
1075 transport_set_vpd_ident(struct t10_vpd *vpd, unsigned char *page_83)
1076 {
1077 	static const char hex_str[] = "0123456789abcdef";
1078 	int j = 0, i = 4; /* offset to start of the identifier */
1079 
1080 	/*
1081 	 * The VPD Code Set (encoding)
1082 	 *
1083 	 * from spc3r23.pdf Section 7.6.3.1 Table 296
1084 	 */
1085 	vpd->device_identifier_code_set = (page_83[0] & 0x0f);
1086 	switch (vpd->device_identifier_code_set) {
1087 	case 0x01: /* Binary */
1088 		vpd->device_identifier[j++] =
1089 				hex_str[vpd->device_identifier_type];
1090 		while (i < (4 + page_83[3])) {
1091 			vpd->device_identifier[j++] =
1092 				hex_str[(page_83[i] & 0xf0) >> 4];
1093 			vpd->device_identifier[j++] =
1094 				hex_str[page_83[i] & 0x0f];
1095 			i++;
1096 		}
1097 		break;
1098 	case 0x02: /* ASCII */
1099 	case 0x03: /* UTF-8 */
1100 		while (i < (4 + page_83[3]))
1101 			vpd->device_identifier[j++] = page_83[i++];
1102 		break;
1103 	default:
1104 		break;
1105 	}
1106 
1107 	return transport_dump_vpd_ident(vpd, NULL, 0);
1108 }
1109 EXPORT_SYMBOL(transport_set_vpd_ident);
1110 
1111 static sense_reason_t
1112 target_check_max_data_sg_nents(struct se_cmd *cmd, struct se_device *dev,
1113 			       unsigned int size)
1114 {
1115 	u32 mtl;
1116 
1117 	if (!cmd->se_tfo->max_data_sg_nents)
1118 		return TCM_NO_SENSE;
1119 	/*
1120 	 * Check if fabric enforced maximum SGL entries per I/O descriptor
1121 	 * exceeds se_cmd->data_length.  If true, set SCF_UNDERFLOW_BIT +
1122 	 * residual_count and reduce original cmd->data_length to maximum
1123 	 * length based on single PAGE_SIZE entry scatter-lists.
1124 	 */
1125 	mtl = (cmd->se_tfo->max_data_sg_nents * PAGE_SIZE);
1126 	if (cmd->data_length > mtl) {
1127 		/*
1128 		 * If an existing CDB overflow is present, calculate new residual
1129 		 * based on CDB size minus fabric maximum transfer length.
1130 		 *
1131 		 * If an existing CDB underflow is present, calculate new residual
1132 		 * based on original cmd->data_length minus fabric maximum transfer
1133 		 * length.
1134 		 *
1135 		 * Otherwise, set the underflow residual based on cmd->data_length
1136 		 * minus fabric maximum transfer length.
1137 		 */
1138 		if (cmd->se_cmd_flags & SCF_OVERFLOW_BIT) {
1139 			cmd->residual_count = (size - mtl);
1140 		} else if (cmd->se_cmd_flags & SCF_UNDERFLOW_BIT) {
1141 			u32 orig_dl = size + cmd->residual_count;
1142 			cmd->residual_count = (orig_dl - mtl);
1143 		} else {
1144 			cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
1145 			cmd->residual_count = (cmd->data_length - mtl);
1146 		}
1147 		cmd->data_length = mtl;
1148 		/*
1149 		 * Reset sbc_check_prot() calculated protection payload
1150 		 * length based upon the new smaller MTL.
1151 		 */
1152 		if (cmd->prot_length) {
1153 			u32 sectors = (mtl / dev->dev_attrib.block_size);
1154 			cmd->prot_length = dev->prot_length * sectors;
1155 		}
1156 	}
1157 	return TCM_NO_SENSE;
1158 }
1159 
1160 sense_reason_t
1161 target_cmd_size_check(struct se_cmd *cmd, unsigned int size)
1162 {
1163 	struct se_device *dev = cmd->se_dev;
1164 
1165 	if (cmd->unknown_data_length) {
1166 		cmd->data_length = size;
1167 	} else if (size != cmd->data_length) {
1168 		pr_warn("TARGET_CORE[%s]: Expected Transfer Length:"
1169 			" %u does not match SCSI CDB Length: %u for SAM Opcode:"
1170 			" 0x%02x\n", cmd->se_tfo->get_fabric_name(),
1171 				cmd->data_length, size, cmd->t_task_cdb[0]);
1172 
1173 		if (cmd->data_direction == DMA_TO_DEVICE &&
1174 		    cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) {
1175 			pr_err("Rejecting underflow/overflow WRITE data\n");
1176 			return TCM_INVALID_CDB_FIELD;
1177 		}
1178 		/*
1179 		 * Reject READ_* or WRITE_* with overflow/underflow for
1180 		 * type SCF_SCSI_DATA_CDB.
1181 		 */
1182 		if (dev->dev_attrib.block_size != 512)  {
1183 			pr_err("Failing OVERFLOW/UNDERFLOW for LBA op"
1184 				" CDB on non 512-byte sector setup subsystem"
1185 				" plugin: %s\n", dev->transport->name);
1186 			/* Returns CHECK_CONDITION + INVALID_CDB_FIELD */
1187 			return TCM_INVALID_CDB_FIELD;
1188 		}
1189 		/*
1190 		 * For the overflow case keep the existing fabric provided
1191 		 * ->data_length.  Otherwise for the underflow case, reset
1192 		 * ->data_length to the smaller SCSI expected data transfer
1193 		 * length.
1194 		 */
1195 		if (size > cmd->data_length) {
1196 			cmd->se_cmd_flags |= SCF_OVERFLOW_BIT;
1197 			cmd->residual_count = (size - cmd->data_length);
1198 		} else {
1199 			cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
1200 			cmd->residual_count = (cmd->data_length - size);
1201 			cmd->data_length = size;
1202 		}
1203 	}
1204 
1205 	return target_check_max_data_sg_nents(cmd, dev, size);
1206 
1207 }
1208 
1209 /*
1210  * Used by fabric modules containing a local struct se_cmd within their
1211  * fabric dependent per I/O descriptor.
1212  *
1213  * Preserves the value of @cmd->tag.
1214  */
1215 void transport_init_se_cmd(
1216 	struct se_cmd *cmd,
1217 	const struct target_core_fabric_ops *tfo,
1218 	struct se_session *se_sess,
1219 	u32 data_length,
1220 	int data_direction,
1221 	int task_attr,
1222 	unsigned char *sense_buffer)
1223 {
1224 	INIT_LIST_HEAD(&cmd->se_delayed_node);
1225 	INIT_LIST_HEAD(&cmd->se_qf_node);
1226 	INIT_LIST_HEAD(&cmd->se_cmd_list);
1227 	INIT_LIST_HEAD(&cmd->state_list);
1228 	init_completion(&cmd->t_transport_stop_comp);
1229 	init_completion(&cmd->cmd_wait_comp);
1230 	spin_lock_init(&cmd->t_state_lock);
1231 	kref_init(&cmd->cmd_kref);
1232 	cmd->transport_state = CMD_T_DEV_ACTIVE;
1233 
1234 	cmd->se_tfo = tfo;
1235 	cmd->se_sess = se_sess;
1236 	cmd->data_length = data_length;
1237 	cmd->data_direction = data_direction;
1238 	cmd->sam_task_attr = task_attr;
1239 	cmd->sense_buffer = sense_buffer;
1240 
1241 	cmd->state_active = false;
1242 }
1243 EXPORT_SYMBOL(transport_init_se_cmd);
1244 
1245 static sense_reason_t
1246 transport_check_alloc_task_attr(struct se_cmd *cmd)
1247 {
1248 	struct se_device *dev = cmd->se_dev;
1249 
1250 	/*
1251 	 * Check if SAM Task Attribute emulation is enabled for this
1252 	 * struct se_device storage object
1253 	 */
1254 	if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
1255 		return 0;
1256 
1257 	if (cmd->sam_task_attr == TCM_ACA_TAG) {
1258 		pr_debug("SAM Task Attribute ACA"
1259 			" emulation is not supported\n");
1260 		return TCM_INVALID_CDB_FIELD;
1261 	}
1262 
1263 	return 0;
1264 }
1265 
1266 sense_reason_t
1267 target_setup_cmd_from_cdb(struct se_cmd *cmd, unsigned char *cdb)
1268 {
1269 	struct se_device *dev = cmd->se_dev;
1270 	sense_reason_t ret;
1271 
1272 	/*
1273 	 * Ensure that the received CDB is less than the max (252 + 8) bytes
1274 	 * for VARIABLE_LENGTH_CMD
1275 	 */
1276 	if (scsi_command_size(cdb) > SCSI_MAX_VARLEN_CDB_SIZE) {
1277 		pr_err("Received SCSI CDB with command_size: %d that"
1278 			" exceeds SCSI_MAX_VARLEN_CDB_SIZE: %d\n",
1279 			scsi_command_size(cdb), SCSI_MAX_VARLEN_CDB_SIZE);
1280 		return TCM_INVALID_CDB_FIELD;
1281 	}
1282 	/*
1283 	 * If the received CDB is larger than TCM_MAX_COMMAND_SIZE,
1284 	 * allocate the additional extended CDB buffer now..  Otherwise
1285 	 * setup the pointer from __t_task_cdb to t_task_cdb.
1286 	 */
1287 	if (scsi_command_size(cdb) > sizeof(cmd->__t_task_cdb)) {
1288 		cmd->t_task_cdb = kzalloc(scsi_command_size(cdb),
1289 						GFP_KERNEL);
1290 		if (!cmd->t_task_cdb) {
1291 			pr_err("Unable to allocate cmd->t_task_cdb"
1292 				" %u > sizeof(cmd->__t_task_cdb): %lu ops\n",
1293 				scsi_command_size(cdb),
1294 				(unsigned long)sizeof(cmd->__t_task_cdb));
1295 			return TCM_OUT_OF_RESOURCES;
1296 		}
1297 	} else
1298 		cmd->t_task_cdb = &cmd->__t_task_cdb[0];
1299 	/*
1300 	 * Copy the original CDB into cmd->
1301 	 */
1302 	memcpy(cmd->t_task_cdb, cdb, scsi_command_size(cdb));
1303 
1304 	trace_target_sequencer_start(cmd);
1305 
1306 	/*
1307 	 * Check for an existing UNIT ATTENTION condition
1308 	 */
1309 	ret = target_scsi3_ua_check(cmd);
1310 	if (ret)
1311 		return ret;
1312 
1313 	ret = target_alua_state_check(cmd);
1314 	if (ret)
1315 		return ret;
1316 
1317 	ret = target_check_reservation(cmd);
1318 	if (ret) {
1319 		cmd->scsi_status = SAM_STAT_RESERVATION_CONFLICT;
1320 		return ret;
1321 	}
1322 
1323 	ret = dev->transport->parse_cdb(cmd);
1324 	if (ret == TCM_UNSUPPORTED_SCSI_OPCODE)
1325 		pr_warn_ratelimited("%s/%s: Unsupported SCSI Opcode 0x%02x, sending CHECK_CONDITION.\n",
1326 				    cmd->se_tfo->get_fabric_name(),
1327 				    cmd->se_sess->se_node_acl->initiatorname,
1328 				    cmd->t_task_cdb[0]);
1329 	if (ret)
1330 		return ret;
1331 
1332 	ret = transport_check_alloc_task_attr(cmd);
1333 	if (ret)
1334 		return ret;
1335 
1336 	cmd->se_cmd_flags |= SCF_SUPPORTED_SAM_OPCODE;
1337 	atomic_long_inc(&cmd->se_lun->lun_stats.cmd_pdus);
1338 	return 0;
1339 }
1340 EXPORT_SYMBOL(target_setup_cmd_from_cdb);
1341 
1342 /*
1343  * Used by fabric module frontends to queue tasks directly.
1344  * May only be used from process context.
1345  */
1346 int transport_handle_cdb_direct(
1347 	struct se_cmd *cmd)
1348 {
1349 	sense_reason_t ret;
1350 
1351 	if (!cmd->se_lun) {
1352 		dump_stack();
1353 		pr_err("cmd->se_lun is NULL\n");
1354 		return -EINVAL;
1355 	}
1356 	if (in_interrupt()) {
1357 		dump_stack();
1358 		pr_err("transport_generic_handle_cdb cannot be called"
1359 				" from interrupt context\n");
1360 		return -EINVAL;
1361 	}
1362 	/*
1363 	 * Set TRANSPORT_NEW_CMD state and CMD_T_ACTIVE to ensure that
1364 	 * outstanding descriptors are handled correctly during shutdown via
1365 	 * transport_wait_for_tasks()
1366 	 *
1367 	 * Also, we don't take cmd->t_state_lock here as we only expect
1368 	 * this to be called for initial descriptor submission.
1369 	 */
1370 	cmd->t_state = TRANSPORT_NEW_CMD;
1371 	cmd->transport_state |= CMD_T_ACTIVE;
1372 
1373 	/*
1374 	 * transport_generic_new_cmd() is already handling QUEUE_FULL,
1375 	 * so follow TRANSPORT_NEW_CMD processing thread context usage
1376 	 * and call transport_generic_request_failure() if necessary..
1377 	 */
1378 	ret = transport_generic_new_cmd(cmd);
1379 	if (ret)
1380 		transport_generic_request_failure(cmd, ret);
1381 	return 0;
1382 }
1383 EXPORT_SYMBOL(transport_handle_cdb_direct);
1384 
1385 sense_reason_t
1386 transport_generic_map_mem_to_cmd(struct se_cmd *cmd, struct scatterlist *sgl,
1387 		u32 sgl_count, struct scatterlist *sgl_bidi, u32 sgl_bidi_count)
1388 {
1389 	if (!sgl || !sgl_count)
1390 		return 0;
1391 
1392 	/*
1393 	 * Reject SCSI data overflow with map_mem_to_cmd() as incoming
1394 	 * scatterlists already have been set to follow what the fabric
1395 	 * passes for the original expected data transfer length.
1396 	 */
1397 	if (cmd->se_cmd_flags & SCF_OVERFLOW_BIT) {
1398 		pr_warn("Rejecting SCSI DATA overflow for fabric using"
1399 			" SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC\n");
1400 		return TCM_INVALID_CDB_FIELD;
1401 	}
1402 
1403 	cmd->t_data_sg = sgl;
1404 	cmd->t_data_nents = sgl_count;
1405 	cmd->t_bidi_data_sg = sgl_bidi;
1406 	cmd->t_bidi_data_nents = sgl_bidi_count;
1407 
1408 	cmd->se_cmd_flags |= SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC;
1409 	return 0;
1410 }
1411 
1412 /*
1413  * target_submit_cmd_map_sgls - lookup unpacked lun and submit uninitialized
1414  * 			 se_cmd + use pre-allocated SGL memory.
1415  *
1416  * @se_cmd: command descriptor to submit
1417  * @se_sess: associated se_sess for endpoint
1418  * @cdb: pointer to SCSI CDB
1419  * @sense: pointer to SCSI sense buffer
1420  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1421  * @data_length: fabric expected data transfer length
1422  * @task_addr: SAM task attribute
1423  * @data_dir: DMA data direction
1424  * @flags: flags for command submission from target_sc_flags_tables
1425  * @sgl: struct scatterlist memory for unidirectional mapping
1426  * @sgl_count: scatterlist count for unidirectional mapping
1427  * @sgl_bidi: struct scatterlist memory for bidirectional READ mapping
1428  * @sgl_bidi_count: scatterlist count for bidirectional READ mapping
1429  * @sgl_prot: struct scatterlist memory protection information
1430  * @sgl_prot_count: scatterlist count for protection information
1431  *
1432  * Task tags are supported if the caller has set @se_cmd->tag.
1433  *
1434  * Returns non zero to signal active I/O shutdown failure.  All other
1435  * setup exceptions will be returned as a SCSI CHECK_CONDITION response,
1436  * but still return zero here.
1437  *
1438  * This may only be called from process context, and also currently
1439  * assumes internal allocation of fabric payload buffer by target-core.
1440  */
1441 int target_submit_cmd_map_sgls(struct se_cmd *se_cmd, struct se_session *se_sess,
1442 		unsigned char *cdb, unsigned char *sense, u64 unpacked_lun,
1443 		u32 data_length, int task_attr, int data_dir, int flags,
1444 		struct scatterlist *sgl, u32 sgl_count,
1445 		struct scatterlist *sgl_bidi, u32 sgl_bidi_count,
1446 		struct scatterlist *sgl_prot, u32 sgl_prot_count)
1447 {
1448 	struct se_portal_group *se_tpg;
1449 	sense_reason_t rc;
1450 	int ret;
1451 
1452 	se_tpg = se_sess->se_tpg;
1453 	BUG_ON(!se_tpg);
1454 	BUG_ON(se_cmd->se_tfo || se_cmd->se_sess);
1455 	BUG_ON(in_interrupt());
1456 	/*
1457 	 * Initialize se_cmd for target operation.  From this point
1458 	 * exceptions are handled by sending exception status via
1459 	 * target_core_fabric_ops->queue_status() callback
1460 	 */
1461 	transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess,
1462 				data_length, data_dir, task_attr, sense);
1463 
1464 	if (flags & TARGET_SCF_USE_CPUID)
1465 		se_cmd->se_cmd_flags |= SCF_USE_CPUID;
1466 	else
1467 		se_cmd->cpuid = WORK_CPU_UNBOUND;
1468 
1469 	if (flags & TARGET_SCF_UNKNOWN_SIZE)
1470 		se_cmd->unknown_data_length = 1;
1471 	/*
1472 	 * Obtain struct se_cmd->cmd_kref reference and add new cmd to
1473 	 * se_sess->sess_cmd_list.  A second kref_get here is necessary
1474 	 * for fabrics using TARGET_SCF_ACK_KREF that expect a second
1475 	 * kref_put() to happen during fabric packet acknowledgement.
1476 	 */
1477 	ret = target_get_sess_cmd(se_cmd, flags & TARGET_SCF_ACK_KREF);
1478 	if (ret)
1479 		return ret;
1480 	/*
1481 	 * Signal bidirectional data payloads to target-core
1482 	 */
1483 	if (flags & TARGET_SCF_BIDI_OP)
1484 		se_cmd->se_cmd_flags |= SCF_BIDI;
1485 	/*
1486 	 * Locate se_lun pointer and attach it to struct se_cmd
1487 	 */
1488 	rc = transport_lookup_cmd_lun(se_cmd, unpacked_lun);
1489 	if (rc) {
1490 		transport_send_check_condition_and_sense(se_cmd, rc, 0);
1491 		target_put_sess_cmd(se_cmd);
1492 		return 0;
1493 	}
1494 
1495 	rc = target_setup_cmd_from_cdb(se_cmd, cdb);
1496 	if (rc != 0) {
1497 		transport_generic_request_failure(se_cmd, rc);
1498 		return 0;
1499 	}
1500 
1501 	/*
1502 	 * Save pointers for SGLs containing protection information,
1503 	 * if present.
1504 	 */
1505 	if (sgl_prot_count) {
1506 		se_cmd->t_prot_sg = sgl_prot;
1507 		se_cmd->t_prot_nents = sgl_prot_count;
1508 		se_cmd->se_cmd_flags |= SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC;
1509 	}
1510 
1511 	/*
1512 	 * When a non zero sgl_count has been passed perform SGL passthrough
1513 	 * mapping for pre-allocated fabric memory instead of having target
1514 	 * core perform an internal SGL allocation..
1515 	 */
1516 	if (sgl_count != 0) {
1517 		BUG_ON(!sgl);
1518 
1519 		/*
1520 		 * A work-around for tcm_loop as some userspace code via
1521 		 * scsi-generic do not memset their associated read buffers,
1522 		 * so go ahead and do that here for type non-data CDBs.  Also
1523 		 * note that this is currently guaranteed to be a single SGL
1524 		 * for this case by target core in target_setup_cmd_from_cdb()
1525 		 * -> transport_generic_cmd_sequencer().
1526 		 */
1527 		if (!(se_cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) &&
1528 		     se_cmd->data_direction == DMA_FROM_DEVICE) {
1529 			unsigned char *buf = NULL;
1530 
1531 			if (sgl)
1532 				buf = kmap(sg_page(sgl)) + sgl->offset;
1533 
1534 			if (buf) {
1535 				memset(buf, 0, sgl->length);
1536 				kunmap(sg_page(sgl));
1537 			}
1538 		}
1539 
1540 		rc = transport_generic_map_mem_to_cmd(se_cmd, sgl, sgl_count,
1541 				sgl_bidi, sgl_bidi_count);
1542 		if (rc != 0) {
1543 			transport_generic_request_failure(se_cmd, rc);
1544 			return 0;
1545 		}
1546 	}
1547 
1548 	/*
1549 	 * Check if we need to delay processing because of ALUA
1550 	 * Active/NonOptimized primary access state..
1551 	 */
1552 	core_alua_check_nonop_delay(se_cmd);
1553 
1554 	transport_handle_cdb_direct(se_cmd);
1555 	return 0;
1556 }
1557 EXPORT_SYMBOL(target_submit_cmd_map_sgls);
1558 
1559 /*
1560  * target_submit_cmd - lookup unpacked lun and submit uninitialized se_cmd
1561  *
1562  * @se_cmd: command descriptor to submit
1563  * @se_sess: associated se_sess for endpoint
1564  * @cdb: pointer to SCSI CDB
1565  * @sense: pointer to SCSI sense buffer
1566  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1567  * @data_length: fabric expected data transfer length
1568  * @task_addr: SAM task attribute
1569  * @data_dir: DMA data direction
1570  * @flags: flags for command submission from target_sc_flags_tables
1571  *
1572  * Task tags are supported if the caller has set @se_cmd->tag.
1573  *
1574  * Returns non zero to signal active I/O shutdown failure.  All other
1575  * setup exceptions will be returned as a SCSI CHECK_CONDITION response,
1576  * but still return zero here.
1577  *
1578  * This may only be called from process context, and also currently
1579  * assumes internal allocation of fabric payload buffer by target-core.
1580  *
1581  * It also assumes interal target core SGL memory allocation.
1582  */
1583 int target_submit_cmd(struct se_cmd *se_cmd, struct se_session *se_sess,
1584 		unsigned char *cdb, unsigned char *sense, u64 unpacked_lun,
1585 		u32 data_length, int task_attr, int data_dir, int flags)
1586 {
1587 	return target_submit_cmd_map_sgls(se_cmd, se_sess, cdb, sense,
1588 			unpacked_lun, data_length, task_attr, data_dir,
1589 			flags, NULL, 0, NULL, 0, NULL, 0);
1590 }
1591 EXPORT_SYMBOL(target_submit_cmd);
1592 
1593 static void target_complete_tmr_failure(struct work_struct *work)
1594 {
1595 	struct se_cmd *se_cmd = container_of(work, struct se_cmd, work);
1596 
1597 	se_cmd->se_tmr_req->response = TMR_LUN_DOES_NOT_EXIST;
1598 	se_cmd->se_tfo->queue_tm_rsp(se_cmd);
1599 
1600 	transport_cmd_check_stop_to_fabric(se_cmd);
1601 }
1602 
1603 /**
1604  * target_submit_tmr - lookup unpacked lun and submit uninitialized se_cmd
1605  *                     for TMR CDBs
1606  *
1607  * @se_cmd: command descriptor to submit
1608  * @se_sess: associated se_sess for endpoint
1609  * @sense: pointer to SCSI sense buffer
1610  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1611  * @fabric_context: fabric context for TMR req
1612  * @tm_type: Type of TM request
1613  * @gfp: gfp type for caller
1614  * @tag: referenced task tag for TMR_ABORT_TASK
1615  * @flags: submit cmd flags
1616  *
1617  * Callable from all contexts.
1618  **/
1619 
1620 int target_submit_tmr(struct se_cmd *se_cmd, struct se_session *se_sess,
1621 		unsigned char *sense, u64 unpacked_lun,
1622 		void *fabric_tmr_ptr, unsigned char tm_type,
1623 		gfp_t gfp, u64 tag, int flags)
1624 {
1625 	struct se_portal_group *se_tpg;
1626 	int ret;
1627 
1628 	se_tpg = se_sess->se_tpg;
1629 	BUG_ON(!se_tpg);
1630 
1631 	transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess,
1632 			      0, DMA_NONE, TCM_SIMPLE_TAG, sense);
1633 	/*
1634 	 * FIXME: Currently expect caller to handle se_cmd->se_tmr_req
1635 	 * allocation failure.
1636 	 */
1637 	ret = core_tmr_alloc_req(se_cmd, fabric_tmr_ptr, tm_type, gfp);
1638 	if (ret < 0)
1639 		return -ENOMEM;
1640 
1641 	if (tm_type == TMR_ABORT_TASK)
1642 		se_cmd->se_tmr_req->ref_task_tag = tag;
1643 
1644 	/* See target_submit_cmd for commentary */
1645 	ret = target_get_sess_cmd(se_cmd, flags & TARGET_SCF_ACK_KREF);
1646 	if (ret) {
1647 		core_tmr_release_req(se_cmd->se_tmr_req);
1648 		return ret;
1649 	}
1650 
1651 	ret = transport_lookup_tmr_lun(se_cmd, unpacked_lun);
1652 	if (ret) {
1653 		/*
1654 		 * For callback during failure handling, push this work off
1655 		 * to process context with TMR_LUN_DOES_NOT_EXIST status.
1656 		 */
1657 		INIT_WORK(&se_cmd->work, target_complete_tmr_failure);
1658 		schedule_work(&se_cmd->work);
1659 		return 0;
1660 	}
1661 	transport_generic_handle_tmr(se_cmd);
1662 	return 0;
1663 }
1664 EXPORT_SYMBOL(target_submit_tmr);
1665 
1666 /*
1667  * Handle SAM-esque emulation for generic transport request failures.
1668  */
1669 void transport_generic_request_failure(struct se_cmd *cmd,
1670 		sense_reason_t sense_reason)
1671 {
1672 	int ret = 0, post_ret = 0;
1673 
1674 	pr_debug("-----[ Storage Engine Exception for cmd: %p ITT: 0x%08llx"
1675 		" CDB: 0x%02x\n", cmd, cmd->tag, cmd->t_task_cdb[0]);
1676 	pr_debug("-----[ i_state: %d t_state: %d sense_reason: %d\n",
1677 		cmd->se_tfo->get_cmd_state(cmd),
1678 		cmd->t_state, sense_reason);
1679 	pr_debug("-----[ CMD_T_ACTIVE: %d CMD_T_STOP: %d CMD_T_SENT: %d\n",
1680 		(cmd->transport_state & CMD_T_ACTIVE) != 0,
1681 		(cmd->transport_state & CMD_T_STOP) != 0,
1682 		(cmd->transport_state & CMD_T_SENT) != 0);
1683 
1684 	/*
1685 	 * For SAM Task Attribute emulation for failed struct se_cmd
1686 	 */
1687 	transport_complete_task_attr(cmd);
1688 	/*
1689 	 * Handle special case for COMPARE_AND_WRITE failure, where the
1690 	 * callback is expected to drop the per device ->caw_sem.
1691 	 */
1692 	if ((cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) &&
1693 	     cmd->transport_complete_callback)
1694 		cmd->transport_complete_callback(cmd, false, &post_ret);
1695 
1696 	switch (sense_reason) {
1697 	case TCM_NON_EXISTENT_LUN:
1698 	case TCM_UNSUPPORTED_SCSI_OPCODE:
1699 	case TCM_INVALID_CDB_FIELD:
1700 	case TCM_INVALID_PARAMETER_LIST:
1701 	case TCM_PARAMETER_LIST_LENGTH_ERROR:
1702 	case TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE:
1703 	case TCM_UNKNOWN_MODE_PAGE:
1704 	case TCM_WRITE_PROTECTED:
1705 	case TCM_ADDRESS_OUT_OF_RANGE:
1706 	case TCM_CHECK_CONDITION_ABORT_CMD:
1707 	case TCM_CHECK_CONDITION_UNIT_ATTENTION:
1708 	case TCM_CHECK_CONDITION_NOT_READY:
1709 	case TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED:
1710 	case TCM_LOGICAL_BLOCK_APP_TAG_CHECK_FAILED:
1711 	case TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED:
1712 		break;
1713 	case TCM_OUT_OF_RESOURCES:
1714 		sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
1715 		break;
1716 	case TCM_RESERVATION_CONFLICT:
1717 		/*
1718 		 * No SENSE Data payload for this case, set SCSI Status
1719 		 * and queue the response to $FABRIC_MOD.
1720 		 *
1721 		 * Uses linux/include/scsi/scsi.h SAM status codes defs
1722 		 */
1723 		cmd->scsi_status = SAM_STAT_RESERVATION_CONFLICT;
1724 		/*
1725 		 * For UA Interlock Code 11b, a RESERVATION CONFLICT will
1726 		 * establish a UNIT ATTENTION with PREVIOUS RESERVATION
1727 		 * CONFLICT STATUS.
1728 		 *
1729 		 * See spc4r17, section 7.4.6 Control Mode Page, Table 349
1730 		 */
1731 		if (cmd->se_sess &&
1732 		    cmd->se_dev->dev_attrib.emulate_ua_intlck_ctrl == 2) {
1733 			target_ua_allocate_lun(cmd->se_sess->se_node_acl,
1734 					       cmd->orig_fe_lun, 0x2C,
1735 					ASCQ_2CH_PREVIOUS_RESERVATION_CONFLICT_STATUS);
1736 		}
1737 		trace_target_cmd_complete(cmd);
1738 		ret = cmd->se_tfo->queue_status(cmd);
1739 		if (ret == -EAGAIN || ret == -ENOMEM)
1740 			goto queue_full;
1741 		goto check_stop;
1742 	default:
1743 		pr_err("Unknown transport error for CDB 0x%02x: %d\n",
1744 			cmd->t_task_cdb[0], sense_reason);
1745 		sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
1746 		break;
1747 	}
1748 
1749 	ret = transport_send_check_condition_and_sense(cmd, sense_reason, 0);
1750 	if (ret == -EAGAIN || ret == -ENOMEM)
1751 		goto queue_full;
1752 
1753 check_stop:
1754 	transport_lun_remove_cmd(cmd);
1755 	transport_cmd_check_stop_to_fabric(cmd);
1756 	return;
1757 
1758 queue_full:
1759 	cmd->t_state = TRANSPORT_COMPLETE_QF_OK;
1760 	transport_handle_queue_full(cmd, cmd->se_dev);
1761 }
1762 EXPORT_SYMBOL(transport_generic_request_failure);
1763 
1764 void __target_execute_cmd(struct se_cmd *cmd)
1765 {
1766 	sense_reason_t ret;
1767 
1768 	if (cmd->execute_cmd) {
1769 		ret = cmd->execute_cmd(cmd);
1770 		if (ret) {
1771 			spin_lock_irq(&cmd->t_state_lock);
1772 			cmd->transport_state &= ~(CMD_T_BUSY|CMD_T_SENT);
1773 			spin_unlock_irq(&cmd->t_state_lock);
1774 
1775 			transport_generic_request_failure(cmd, ret);
1776 		}
1777 	}
1778 }
1779 
1780 static int target_write_prot_action(struct se_cmd *cmd)
1781 {
1782 	u32 sectors;
1783 	/*
1784 	 * Perform WRITE_INSERT of PI using software emulation when backend
1785 	 * device has PI enabled, if the transport has not already generated
1786 	 * PI using hardware WRITE_INSERT offload.
1787 	 */
1788 	switch (cmd->prot_op) {
1789 	case TARGET_PROT_DOUT_INSERT:
1790 		if (!(cmd->se_sess->sup_prot_ops & TARGET_PROT_DOUT_INSERT))
1791 			sbc_dif_generate(cmd);
1792 		break;
1793 	case TARGET_PROT_DOUT_STRIP:
1794 		if (cmd->se_sess->sup_prot_ops & TARGET_PROT_DOUT_STRIP)
1795 			break;
1796 
1797 		sectors = cmd->data_length >> ilog2(cmd->se_dev->dev_attrib.block_size);
1798 		cmd->pi_err = sbc_dif_verify(cmd, cmd->t_task_lba,
1799 					     sectors, 0, cmd->t_prot_sg, 0);
1800 		if (unlikely(cmd->pi_err)) {
1801 			spin_lock_irq(&cmd->t_state_lock);
1802 			cmd->transport_state &= ~(CMD_T_BUSY|CMD_T_SENT);
1803 			spin_unlock_irq(&cmd->t_state_lock);
1804 			transport_generic_request_failure(cmd, cmd->pi_err);
1805 			return -1;
1806 		}
1807 		break;
1808 	default:
1809 		break;
1810 	}
1811 
1812 	return 0;
1813 }
1814 
1815 static bool target_handle_task_attr(struct se_cmd *cmd)
1816 {
1817 	struct se_device *dev = cmd->se_dev;
1818 
1819 	if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
1820 		return false;
1821 
1822 	/*
1823 	 * Check for the existence of HEAD_OF_QUEUE, and if true return 1
1824 	 * to allow the passed struct se_cmd list of tasks to the front of the list.
1825 	 */
1826 	switch (cmd->sam_task_attr) {
1827 	case TCM_HEAD_TAG:
1828 		pr_debug("Added HEAD_OF_QUEUE for CDB: 0x%02x\n",
1829 			 cmd->t_task_cdb[0]);
1830 		return false;
1831 	case TCM_ORDERED_TAG:
1832 		atomic_inc_mb(&dev->dev_ordered_sync);
1833 
1834 		pr_debug("Added ORDERED for CDB: 0x%02x to ordered list\n",
1835 			 cmd->t_task_cdb[0]);
1836 
1837 		/*
1838 		 * Execute an ORDERED command if no other older commands
1839 		 * exist that need to be completed first.
1840 		 */
1841 		if (!atomic_read(&dev->simple_cmds))
1842 			return false;
1843 		break;
1844 	default:
1845 		/*
1846 		 * For SIMPLE and UNTAGGED Task Attribute commands
1847 		 */
1848 		atomic_inc_mb(&dev->simple_cmds);
1849 		break;
1850 	}
1851 
1852 	if (atomic_read(&dev->dev_ordered_sync) == 0)
1853 		return false;
1854 
1855 	spin_lock(&dev->delayed_cmd_lock);
1856 	list_add_tail(&cmd->se_delayed_node, &dev->delayed_cmd_list);
1857 	spin_unlock(&dev->delayed_cmd_lock);
1858 
1859 	pr_debug("Added CDB: 0x%02x Task Attr: 0x%02x to delayed CMD listn",
1860 		cmd->t_task_cdb[0], cmd->sam_task_attr);
1861 	return true;
1862 }
1863 
1864 static int __transport_check_aborted_status(struct se_cmd *, int);
1865 
1866 void target_execute_cmd(struct se_cmd *cmd)
1867 {
1868 	/*
1869 	 * Determine if frontend context caller is requesting the stopping of
1870 	 * this command for frontend exceptions.
1871 	 *
1872 	 * If the received CDB has aleady been aborted stop processing it here.
1873 	 */
1874 	spin_lock_irq(&cmd->t_state_lock);
1875 	if (__transport_check_aborted_status(cmd, 1)) {
1876 		spin_unlock_irq(&cmd->t_state_lock);
1877 		return;
1878 	}
1879 	if (cmd->transport_state & CMD_T_STOP) {
1880 		pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08llx\n",
1881 			__func__, __LINE__, cmd->tag);
1882 
1883 		spin_unlock_irq(&cmd->t_state_lock);
1884 		complete_all(&cmd->t_transport_stop_comp);
1885 		return;
1886 	}
1887 
1888 	cmd->t_state = TRANSPORT_PROCESSING;
1889 	cmd->transport_state |= CMD_T_ACTIVE|CMD_T_BUSY|CMD_T_SENT;
1890 	spin_unlock_irq(&cmd->t_state_lock);
1891 
1892 	if (target_write_prot_action(cmd))
1893 		return;
1894 
1895 	if (target_handle_task_attr(cmd)) {
1896 		spin_lock_irq(&cmd->t_state_lock);
1897 		cmd->transport_state &= ~(CMD_T_BUSY | CMD_T_SENT);
1898 		spin_unlock_irq(&cmd->t_state_lock);
1899 		return;
1900 	}
1901 
1902 	__target_execute_cmd(cmd);
1903 }
1904 EXPORT_SYMBOL(target_execute_cmd);
1905 
1906 /*
1907  * Process all commands up to the last received ORDERED task attribute which
1908  * requires another blocking boundary
1909  */
1910 static void target_restart_delayed_cmds(struct se_device *dev)
1911 {
1912 	for (;;) {
1913 		struct se_cmd *cmd;
1914 
1915 		spin_lock(&dev->delayed_cmd_lock);
1916 		if (list_empty(&dev->delayed_cmd_list)) {
1917 			spin_unlock(&dev->delayed_cmd_lock);
1918 			break;
1919 		}
1920 
1921 		cmd = list_entry(dev->delayed_cmd_list.next,
1922 				 struct se_cmd, se_delayed_node);
1923 		list_del(&cmd->se_delayed_node);
1924 		spin_unlock(&dev->delayed_cmd_lock);
1925 
1926 		__target_execute_cmd(cmd);
1927 
1928 		if (cmd->sam_task_attr == TCM_ORDERED_TAG)
1929 			break;
1930 	}
1931 }
1932 
1933 /*
1934  * Called from I/O completion to determine which dormant/delayed
1935  * and ordered cmds need to have their tasks added to the execution queue.
1936  */
1937 static void transport_complete_task_attr(struct se_cmd *cmd)
1938 {
1939 	struct se_device *dev = cmd->se_dev;
1940 
1941 	if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
1942 		return;
1943 
1944 	if (cmd->sam_task_attr == TCM_SIMPLE_TAG) {
1945 		atomic_dec_mb(&dev->simple_cmds);
1946 		dev->dev_cur_ordered_id++;
1947 		pr_debug("Incremented dev->dev_cur_ordered_id: %u for SIMPLE\n",
1948 			 dev->dev_cur_ordered_id);
1949 	} else if (cmd->sam_task_attr == TCM_HEAD_TAG) {
1950 		dev->dev_cur_ordered_id++;
1951 		pr_debug("Incremented dev_cur_ordered_id: %u for HEAD_OF_QUEUE\n",
1952 			 dev->dev_cur_ordered_id);
1953 	} else if (cmd->sam_task_attr == TCM_ORDERED_TAG) {
1954 		atomic_dec_mb(&dev->dev_ordered_sync);
1955 
1956 		dev->dev_cur_ordered_id++;
1957 		pr_debug("Incremented dev_cur_ordered_id: %u for ORDERED\n",
1958 			 dev->dev_cur_ordered_id);
1959 	}
1960 
1961 	target_restart_delayed_cmds(dev);
1962 }
1963 
1964 static void transport_complete_qf(struct se_cmd *cmd)
1965 {
1966 	int ret = 0;
1967 
1968 	transport_complete_task_attr(cmd);
1969 
1970 	if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) {
1971 		trace_target_cmd_complete(cmd);
1972 		ret = cmd->se_tfo->queue_status(cmd);
1973 		goto out;
1974 	}
1975 
1976 	switch (cmd->data_direction) {
1977 	case DMA_FROM_DEVICE:
1978 		if (cmd->scsi_status)
1979 			goto queue_status;
1980 
1981 		trace_target_cmd_complete(cmd);
1982 		ret = cmd->se_tfo->queue_data_in(cmd);
1983 		break;
1984 	case DMA_TO_DEVICE:
1985 		if (cmd->se_cmd_flags & SCF_BIDI) {
1986 			ret = cmd->se_tfo->queue_data_in(cmd);
1987 			break;
1988 		}
1989 		/* Fall through for DMA_TO_DEVICE */
1990 	case DMA_NONE:
1991 queue_status:
1992 		trace_target_cmd_complete(cmd);
1993 		ret = cmd->se_tfo->queue_status(cmd);
1994 		break;
1995 	default:
1996 		break;
1997 	}
1998 
1999 out:
2000 	if (ret < 0) {
2001 		transport_handle_queue_full(cmd, cmd->se_dev);
2002 		return;
2003 	}
2004 	transport_lun_remove_cmd(cmd);
2005 	transport_cmd_check_stop_to_fabric(cmd);
2006 }
2007 
2008 static void transport_handle_queue_full(
2009 	struct se_cmd *cmd,
2010 	struct se_device *dev)
2011 {
2012 	spin_lock_irq(&dev->qf_cmd_lock);
2013 	list_add_tail(&cmd->se_qf_node, &cmd->se_dev->qf_cmd_list);
2014 	atomic_inc_mb(&dev->dev_qf_count);
2015 	spin_unlock_irq(&cmd->se_dev->qf_cmd_lock);
2016 
2017 	schedule_work(&cmd->se_dev->qf_work_queue);
2018 }
2019 
2020 static bool target_read_prot_action(struct se_cmd *cmd)
2021 {
2022 	switch (cmd->prot_op) {
2023 	case TARGET_PROT_DIN_STRIP:
2024 		if (!(cmd->se_sess->sup_prot_ops & TARGET_PROT_DIN_STRIP)) {
2025 			u32 sectors = cmd->data_length >>
2026 				  ilog2(cmd->se_dev->dev_attrib.block_size);
2027 
2028 			cmd->pi_err = sbc_dif_verify(cmd, cmd->t_task_lba,
2029 						     sectors, 0, cmd->t_prot_sg,
2030 						     0);
2031 			if (cmd->pi_err)
2032 				return true;
2033 		}
2034 		break;
2035 	case TARGET_PROT_DIN_INSERT:
2036 		if (cmd->se_sess->sup_prot_ops & TARGET_PROT_DIN_INSERT)
2037 			break;
2038 
2039 		sbc_dif_generate(cmd);
2040 		break;
2041 	default:
2042 		break;
2043 	}
2044 
2045 	return false;
2046 }
2047 
2048 static void target_complete_ok_work(struct work_struct *work)
2049 {
2050 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
2051 	int ret;
2052 
2053 	/*
2054 	 * Check if we need to move delayed/dormant tasks from cmds on the
2055 	 * delayed execution list after a HEAD_OF_QUEUE or ORDERED Task
2056 	 * Attribute.
2057 	 */
2058 	transport_complete_task_attr(cmd);
2059 
2060 	/*
2061 	 * Check to schedule QUEUE_FULL work, or execute an existing
2062 	 * cmd->transport_qf_callback()
2063 	 */
2064 	if (atomic_read(&cmd->se_dev->dev_qf_count) != 0)
2065 		schedule_work(&cmd->se_dev->qf_work_queue);
2066 
2067 	/*
2068 	 * Check if we need to send a sense buffer from
2069 	 * the struct se_cmd in question.
2070 	 */
2071 	if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) {
2072 		WARN_ON(!cmd->scsi_status);
2073 		ret = transport_send_check_condition_and_sense(
2074 					cmd, 0, 1);
2075 		if (ret == -EAGAIN || ret == -ENOMEM)
2076 			goto queue_full;
2077 
2078 		transport_lun_remove_cmd(cmd);
2079 		transport_cmd_check_stop_to_fabric(cmd);
2080 		return;
2081 	}
2082 	/*
2083 	 * Check for a callback, used by amongst other things
2084 	 * XDWRITE_READ_10 and COMPARE_AND_WRITE emulation.
2085 	 */
2086 	if (cmd->transport_complete_callback) {
2087 		sense_reason_t rc;
2088 		bool caw = (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE);
2089 		bool zero_dl = !(cmd->data_length);
2090 		int post_ret = 0;
2091 
2092 		rc = cmd->transport_complete_callback(cmd, true, &post_ret);
2093 		if (!rc && !post_ret) {
2094 			if (caw && zero_dl)
2095 				goto queue_rsp;
2096 
2097 			return;
2098 		} else if (rc) {
2099 			ret = transport_send_check_condition_and_sense(cmd,
2100 						rc, 0);
2101 			if (ret == -EAGAIN || ret == -ENOMEM)
2102 				goto queue_full;
2103 
2104 			transport_lun_remove_cmd(cmd);
2105 			transport_cmd_check_stop_to_fabric(cmd);
2106 			return;
2107 		}
2108 	}
2109 
2110 queue_rsp:
2111 	switch (cmd->data_direction) {
2112 	case DMA_FROM_DEVICE:
2113 		if (cmd->scsi_status)
2114 			goto queue_status;
2115 
2116 		atomic_long_add(cmd->data_length,
2117 				&cmd->se_lun->lun_stats.tx_data_octets);
2118 		/*
2119 		 * Perform READ_STRIP of PI using software emulation when
2120 		 * backend had PI enabled, if the transport will not be
2121 		 * performing hardware READ_STRIP offload.
2122 		 */
2123 		if (target_read_prot_action(cmd)) {
2124 			ret = transport_send_check_condition_and_sense(cmd,
2125 						cmd->pi_err, 0);
2126 			if (ret == -EAGAIN || ret == -ENOMEM)
2127 				goto queue_full;
2128 
2129 			transport_lun_remove_cmd(cmd);
2130 			transport_cmd_check_stop_to_fabric(cmd);
2131 			return;
2132 		}
2133 
2134 		trace_target_cmd_complete(cmd);
2135 		ret = cmd->se_tfo->queue_data_in(cmd);
2136 		if (ret == -EAGAIN || ret == -ENOMEM)
2137 			goto queue_full;
2138 		break;
2139 	case DMA_TO_DEVICE:
2140 		atomic_long_add(cmd->data_length,
2141 				&cmd->se_lun->lun_stats.rx_data_octets);
2142 		/*
2143 		 * Check if we need to send READ payload for BIDI-COMMAND
2144 		 */
2145 		if (cmd->se_cmd_flags & SCF_BIDI) {
2146 			atomic_long_add(cmd->data_length,
2147 					&cmd->se_lun->lun_stats.tx_data_octets);
2148 			ret = cmd->se_tfo->queue_data_in(cmd);
2149 			if (ret == -EAGAIN || ret == -ENOMEM)
2150 				goto queue_full;
2151 			break;
2152 		}
2153 		/* Fall through for DMA_TO_DEVICE */
2154 	case DMA_NONE:
2155 queue_status:
2156 		trace_target_cmd_complete(cmd);
2157 		ret = cmd->se_tfo->queue_status(cmd);
2158 		if (ret == -EAGAIN || ret == -ENOMEM)
2159 			goto queue_full;
2160 		break;
2161 	default:
2162 		break;
2163 	}
2164 
2165 	transport_lun_remove_cmd(cmd);
2166 	transport_cmd_check_stop_to_fabric(cmd);
2167 	return;
2168 
2169 queue_full:
2170 	pr_debug("Handling complete_ok QUEUE_FULL: se_cmd: %p,"
2171 		" data_direction: %d\n", cmd, cmd->data_direction);
2172 	cmd->t_state = TRANSPORT_COMPLETE_QF_OK;
2173 	transport_handle_queue_full(cmd, cmd->se_dev);
2174 }
2175 
2176 void target_free_sgl(struct scatterlist *sgl, int nents)
2177 {
2178 	struct scatterlist *sg;
2179 	int count;
2180 
2181 	for_each_sg(sgl, sg, nents, count)
2182 		__free_page(sg_page(sg));
2183 
2184 	kfree(sgl);
2185 }
2186 EXPORT_SYMBOL(target_free_sgl);
2187 
2188 static inline void transport_reset_sgl_orig(struct se_cmd *cmd)
2189 {
2190 	/*
2191 	 * Check for saved t_data_sg that may be used for COMPARE_AND_WRITE
2192 	 * emulation, and free + reset pointers if necessary..
2193 	 */
2194 	if (!cmd->t_data_sg_orig)
2195 		return;
2196 
2197 	kfree(cmd->t_data_sg);
2198 	cmd->t_data_sg = cmd->t_data_sg_orig;
2199 	cmd->t_data_sg_orig = NULL;
2200 	cmd->t_data_nents = cmd->t_data_nents_orig;
2201 	cmd->t_data_nents_orig = 0;
2202 }
2203 
2204 static inline void transport_free_pages(struct se_cmd *cmd)
2205 {
2206 	if (!(cmd->se_cmd_flags & SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC)) {
2207 		target_free_sgl(cmd->t_prot_sg, cmd->t_prot_nents);
2208 		cmd->t_prot_sg = NULL;
2209 		cmd->t_prot_nents = 0;
2210 	}
2211 
2212 	if (cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) {
2213 		/*
2214 		 * Release special case READ buffer payload required for
2215 		 * SG_TO_MEM_NOALLOC to function with COMPARE_AND_WRITE
2216 		 */
2217 		if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) {
2218 			target_free_sgl(cmd->t_bidi_data_sg,
2219 					   cmd->t_bidi_data_nents);
2220 			cmd->t_bidi_data_sg = NULL;
2221 			cmd->t_bidi_data_nents = 0;
2222 		}
2223 		transport_reset_sgl_orig(cmd);
2224 		return;
2225 	}
2226 	transport_reset_sgl_orig(cmd);
2227 
2228 	target_free_sgl(cmd->t_data_sg, cmd->t_data_nents);
2229 	cmd->t_data_sg = NULL;
2230 	cmd->t_data_nents = 0;
2231 
2232 	target_free_sgl(cmd->t_bidi_data_sg, cmd->t_bidi_data_nents);
2233 	cmd->t_bidi_data_sg = NULL;
2234 	cmd->t_bidi_data_nents = 0;
2235 }
2236 
2237 /**
2238  * transport_put_cmd - release a reference to a command
2239  * @cmd:       command to release
2240  *
2241  * This routine releases our reference to the command and frees it if possible.
2242  */
2243 static int transport_put_cmd(struct se_cmd *cmd)
2244 {
2245 	BUG_ON(!cmd->se_tfo);
2246 	/*
2247 	 * If this cmd has been setup with target_get_sess_cmd(), drop
2248 	 * the kref and call ->release_cmd() in kref callback.
2249 	 */
2250 	return target_put_sess_cmd(cmd);
2251 }
2252 
2253 void *transport_kmap_data_sg(struct se_cmd *cmd)
2254 {
2255 	struct scatterlist *sg = cmd->t_data_sg;
2256 	struct page **pages;
2257 	int i;
2258 
2259 	/*
2260 	 * We need to take into account a possible offset here for fabrics like
2261 	 * tcm_loop who may be using a contig buffer from the SCSI midlayer for
2262 	 * control CDBs passed as SGLs via transport_generic_map_mem_to_cmd()
2263 	 */
2264 	if (!cmd->t_data_nents)
2265 		return NULL;
2266 
2267 	BUG_ON(!sg);
2268 	if (cmd->t_data_nents == 1)
2269 		return kmap(sg_page(sg)) + sg->offset;
2270 
2271 	/* >1 page. use vmap */
2272 	pages = kmalloc(sizeof(*pages) * cmd->t_data_nents, GFP_KERNEL);
2273 	if (!pages)
2274 		return NULL;
2275 
2276 	/* convert sg[] to pages[] */
2277 	for_each_sg(cmd->t_data_sg, sg, cmd->t_data_nents, i) {
2278 		pages[i] = sg_page(sg);
2279 	}
2280 
2281 	cmd->t_data_vmap = vmap(pages, cmd->t_data_nents,  VM_MAP, PAGE_KERNEL);
2282 	kfree(pages);
2283 	if (!cmd->t_data_vmap)
2284 		return NULL;
2285 
2286 	return cmd->t_data_vmap + cmd->t_data_sg[0].offset;
2287 }
2288 EXPORT_SYMBOL(transport_kmap_data_sg);
2289 
2290 void transport_kunmap_data_sg(struct se_cmd *cmd)
2291 {
2292 	if (!cmd->t_data_nents) {
2293 		return;
2294 	} else if (cmd->t_data_nents == 1) {
2295 		kunmap(sg_page(cmd->t_data_sg));
2296 		return;
2297 	}
2298 
2299 	vunmap(cmd->t_data_vmap);
2300 	cmd->t_data_vmap = NULL;
2301 }
2302 EXPORT_SYMBOL(transport_kunmap_data_sg);
2303 
2304 int
2305 target_alloc_sgl(struct scatterlist **sgl, unsigned int *nents, u32 length,
2306 		 bool zero_page, bool chainable)
2307 {
2308 	struct scatterlist *sg;
2309 	struct page *page;
2310 	gfp_t zero_flag = (zero_page) ? __GFP_ZERO : 0;
2311 	unsigned int nalloc, nent;
2312 	int i = 0;
2313 
2314 	nalloc = nent = DIV_ROUND_UP(length, PAGE_SIZE);
2315 	if (chainable)
2316 		nalloc++;
2317 	sg = kmalloc_array(nalloc, sizeof(struct scatterlist), GFP_KERNEL);
2318 	if (!sg)
2319 		return -ENOMEM;
2320 
2321 	sg_init_table(sg, nalloc);
2322 
2323 	while (length) {
2324 		u32 page_len = min_t(u32, length, PAGE_SIZE);
2325 		page = alloc_page(GFP_KERNEL | zero_flag);
2326 		if (!page)
2327 			goto out;
2328 
2329 		sg_set_page(&sg[i], page, page_len, 0);
2330 		length -= page_len;
2331 		i++;
2332 	}
2333 	*sgl = sg;
2334 	*nents = nent;
2335 	return 0;
2336 
2337 out:
2338 	while (i > 0) {
2339 		i--;
2340 		__free_page(sg_page(&sg[i]));
2341 	}
2342 	kfree(sg);
2343 	return -ENOMEM;
2344 }
2345 EXPORT_SYMBOL(target_alloc_sgl);
2346 
2347 /*
2348  * Allocate any required resources to execute the command.  For writes we
2349  * might not have the payload yet, so notify the fabric via a call to
2350  * ->write_pending instead. Otherwise place it on the execution queue.
2351  */
2352 sense_reason_t
2353 transport_generic_new_cmd(struct se_cmd *cmd)
2354 {
2355 	int ret = 0;
2356 	bool zero_flag = !(cmd->se_cmd_flags & SCF_SCSI_DATA_CDB);
2357 
2358 	if (cmd->prot_op != TARGET_PROT_NORMAL &&
2359 	    !(cmd->se_cmd_flags & SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC)) {
2360 		ret = target_alloc_sgl(&cmd->t_prot_sg, &cmd->t_prot_nents,
2361 				       cmd->prot_length, true, false);
2362 		if (ret < 0)
2363 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2364 	}
2365 
2366 	/*
2367 	 * Determine is the TCM fabric module has already allocated physical
2368 	 * memory, and is directly calling transport_generic_map_mem_to_cmd()
2369 	 * beforehand.
2370 	 */
2371 	if (!(cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) &&
2372 	    cmd->data_length) {
2373 
2374 		if ((cmd->se_cmd_flags & SCF_BIDI) ||
2375 		    (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE)) {
2376 			u32 bidi_length;
2377 
2378 			if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE)
2379 				bidi_length = cmd->t_task_nolb *
2380 					      cmd->se_dev->dev_attrib.block_size;
2381 			else
2382 				bidi_length = cmd->data_length;
2383 
2384 			ret = target_alloc_sgl(&cmd->t_bidi_data_sg,
2385 					       &cmd->t_bidi_data_nents,
2386 					       bidi_length, zero_flag, false);
2387 			if (ret < 0)
2388 				return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2389 		}
2390 
2391 		ret = target_alloc_sgl(&cmd->t_data_sg, &cmd->t_data_nents,
2392 				       cmd->data_length, zero_flag, false);
2393 		if (ret < 0)
2394 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2395 	} else if ((cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) &&
2396 		    cmd->data_length) {
2397 		/*
2398 		 * Special case for COMPARE_AND_WRITE with fabrics
2399 		 * using SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC.
2400 		 */
2401 		u32 caw_length = cmd->t_task_nolb *
2402 				 cmd->se_dev->dev_attrib.block_size;
2403 
2404 		ret = target_alloc_sgl(&cmd->t_bidi_data_sg,
2405 				       &cmd->t_bidi_data_nents,
2406 				       caw_length, zero_flag, false);
2407 		if (ret < 0)
2408 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2409 	}
2410 	/*
2411 	 * If this command is not a write we can execute it right here,
2412 	 * for write buffers we need to notify the fabric driver first
2413 	 * and let it call back once the write buffers are ready.
2414 	 */
2415 	target_add_to_state_list(cmd);
2416 	if (cmd->data_direction != DMA_TO_DEVICE || cmd->data_length == 0) {
2417 		target_execute_cmd(cmd);
2418 		return 0;
2419 	}
2420 	transport_cmd_check_stop(cmd, false, true);
2421 
2422 	ret = cmd->se_tfo->write_pending(cmd);
2423 	if (ret == -EAGAIN || ret == -ENOMEM)
2424 		goto queue_full;
2425 
2426 	/* fabric drivers should only return -EAGAIN or -ENOMEM as error */
2427 	WARN_ON(ret);
2428 
2429 	return (!ret) ? 0 : TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2430 
2431 queue_full:
2432 	pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n", cmd);
2433 	cmd->t_state = TRANSPORT_COMPLETE_QF_WP;
2434 	transport_handle_queue_full(cmd, cmd->se_dev);
2435 	return 0;
2436 }
2437 EXPORT_SYMBOL(transport_generic_new_cmd);
2438 
2439 static void transport_write_pending_qf(struct se_cmd *cmd)
2440 {
2441 	int ret;
2442 
2443 	ret = cmd->se_tfo->write_pending(cmd);
2444 	if (ret == -EAGAIN || ret == -ENOMEM) {
2445 		pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n",
2446 			 cmd);
2447 		transport_handle_queue_full(cmd, cmd->se_dev);
2448 	}
2449 }
2450 
2451 static bool
2452 __transport_wait_for_tasks(struct se_cmd *, bool, bool *, bool *,
2453 			   unsigned long *flags);
2454 
2455 static void target_wait_free_cmd(struct se_cmd *cmd, bool *aborted, bool *tas)
2456 {
2457 	unsigned long flags;
2458 
2459 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2460 	__transport_wait_for_tasks(cmd, true, aborted, tas, &flags);
2461 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2462 }
2463 
2464 int transport_generic_free_cmd(struct se_cmd *cmd, int wait_for_tasks)
2465 {
2466 	int ret = 0;
2467 	bool aborted = false, tas = false;
2468 
2469 	if (!(cmd->se_cmd_flags & SCF_SE_LUN_CMD)) {
2470 		if (wait_for_tasks && (cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
2471 			target_wait_free_cmd(cmd, &aborted, &tas);
2472 
2473 		if (!aborted || tas)
2474 			ret = transport_put_cmd(cmd);
2475 	} else {
2476 		if (wait_for_tasks)
2477 			target_wait_free_cmd(cmd, &aborted, &tas);
2478 		/*
2479 		 * Handle WRITE failure case where transport_generic_new_cmd()
2480 		 * has already added se_cmd to state_list, but fabric has
2481 		 * failed command before I/O submission.
2482 		 */
2483 		if (cmd->state_active)
2484 			target_remove_from_state_list(cmd);
2485 
2486 		if (cmd->se_lun)
2487 			transport_lun_remove_cmd(cmd);
2488 
2489 		if (!aborted || tas)
2490 			ret = transport_put_cmd(cmd);
2491 	}
2492 	/*
2493 	 * If the task has been internally aborted due to TMR ABORT_TASK
2494 	 * or LUN_RESET, target_core_tmr.c is responsible for performing
2495 	 * the remaining calls to target_put_sess_cmd(), and not the
2496 	 * callers of this function.
2497 	 */
2498 	if (aborted) {
2499 		pr_debug("Detected CMD_T_ABORTED for ITT: %llu\n", cmd->tag);
2500 		wait_for_completion(&cmd->cmd_wait_comp);
2501 		cmd->se_tfo->release_cmd(cmd);
2502 		ret = 1;
2503 	}
2504 	return ret;
2505 }
2506 EXPORT_SYMBOL(transport_generic_free_cmd);
2507 
2508 /* target_get_sess_cmd - Add command to active ->sess_cmd_list
2509  * @se_cmd:	command descriptor to add
2510  * @ack_kref:	Signal that fabric will perform an ack target_put_sess_cmd()
2511  */
2512 int target_get_sess_cmd(struct se_cmd *se_cmd, bool ack_kref)
2513 {
2514 	struct se_session *se_sess = se_cmd->se_sess;
2515 	unsigned long flags;
2516 	int ret = 0;
2517 
2518 	/*
2519 	 * Add a second kref if the fabric caller is expecting to handle
2520 	 * fabric acknowledgement that requires two target_put_sess_cmd()
2521 	 * invocations before se_cmd descriptor release.
2522 	 */
2523 	if (ack_kref)
2524 		kref_get(&se_cmd->cmd_kref);
2525 
2526 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2527 	if (se_sess->sess_tearing_down) {
2528 		ret = -ESHUTDOWN;
2529 		goto out;
2530 	}
2531 	list_add_tail(&se_cmd->se_cmd_list, &se_sess->sess_cmd_list);
2532 out:
2533 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2534 
2535 	if (ret && ack_kref)
2536 		target_put_sess_cmd(se_cmd);
2537 
2538 	return ret;
2539 }
2540 EXPORT_SYMBOL(target_get_sess_cmd);
2541 
2542 static void target_free_cmd_mem(struct se_cmd *cmd)
2543 {
2544 	transport_free_pages(cmd);
2545 
2546 	if (cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
2547 		core_tmr_release_req(cmd->se_tmr_req);
2548 	if (cmd->t_task_cdb != cmd->__t_task_cdb)
2549 		kfree(cmd->t_task_cdb);
2550 }
2551 
2552 static void target_release_cmd_kref(struct kref *kref)
2553 {
2554 	struct se_cmd *se_cmd = container_of(kref, struct se_cmd, cmd_kref);
2555 	struct se_session *se_sess = se_cmd->se_sess;
2556 	unsigned long flags;
2557 	bool fabric_stop;
2558 
2559 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2560 	if (list_empty(&se_cmd->se_cmd_list)) {
2561 		spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2562 		target_free_cmd_mem(se_cmd);
2563 		se_cmd->se_tfo->release_cmd(se_cmd);
2564 		return;
2565 	}
2566 
2567 	spin_lock(&se_cmd->t_state_lock);
2568 	fabric_stop = (se_cmd->transport_state & CMD_T_FABRIC_STOP);
2569 	spin_unlock(&se_cmd->t_state_lock);
2570 
2571 	if (se_cmd->cmd_wait_set || fabric_stop) {
2572 		list_del_init(&se_cmd->se_cmd_list);
2573 		spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2574 		target_free_cmd_mem(se_cmd);
2575 		complete(&se_cmd->cmd_wait_comp);
2576 		return;
2577 	}
2578 	list_del_init(&se_cmd->se_cmd_list);
2579 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2580 
2581 	target_free_cmd_mem(se_cmd);
2582 	se_cmd->se_tfo->release_cmd(se_cmd);
2583 }
2584 
2585 /* target_put_sess_cmd - Check for active I/O shutdown via kref_put
2586  * @se_cmd:	command descriptor to drop
2587  */
2588 int target_put_sess_cmd(struct se_cmd *se_cmd)
2589 {
2590 	struct se_session *se_sess = se_cmd->se_sess;
2591 
2592 	if (!se_sess) {
2593 		target_free_cmd_mem(se_cmd);
2594 		se_cmd->se_tfo->release_cmd(se_cmd);
2595 		return 1;
2596 	}
2597 	return kref_put(&se_cmd->cmd_kref, target_release_cmd_kref);
2598 }
2599 EXPORT_SYMBOL(target_put_sess_cmd);
2600 
2601 /* target_sess_cmd_list_set_waiting - Flag all commands in
2602  *         sess_cmd_list to complete cmd_wait_comp.  Set
2603  *         sess_tearing_down so no more commands are queued.
2604  * @se_sess:	session to flag
2605  */
2606 void target_sess_cmd_list_set_waiting(struct se_session *se_sess)
2607 {
2608 	struct se_cmd *se_cmd;
2609 	unsigned long flags;
2610 	int rc;
2611 
2612 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2613 	if (se_sess->sess_tearing_down) {
2614 		spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2615 		return;
2616 	}
2617 	se_sess->sess_tearing_down = 1;
2618 	list_splice_init(&se_sess->sess_cmd_list, &se_sess->sess_wait_list);
2619 
2620 	list_for_each_entry(se_cmd, &se_sess->sess_wait_list, se_cmd_list) {
2621 		rc = kref_get_unless_zero(&se_cmd->cmd_kref);
2622 		if (rc) {
2623 			se_cmd->cmd_wait_set = 1;
2624 			spin_lock(&se_cmd->t_state_lock);
2625 			se_cmd->transport_state |= CMD_T_FABRIC_STOP;
2626 			spin_unlock(&se_cmd->t_state_lock);
2627 		}
2628 	}
2629 
2630 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2631 }
2632 EXPORT_SYMBOL(target_sess_cmd_list_set_waiting);
2633 
2634 /* target_wait_for_sess_cmds - Wait for outstanding descriptors
2635  * @se_sess:    session to wait for active I/O
2636  */
2637 void target_wait_for_sess_cmds(struct se_session *se_sess)
2638 {
2639 	struct se_cmd *se_cmd, *tmp_cmd;
2640 	unsigned long flags;
2641 	bool tas;
2642 
2643 	list_for_each_entry_safe(se_cmd, tmp_cmd,
2644 				&se_sess->sess_wait_list, se_cmd_list) {
2645 		pr_debug("Waiting for se_cmd: %p t_state: %d, fabric state:"
2646 			" %d\n", se_cmd, se_cmd->t_state,
2647 			se_cmd->se_tfo->get_cmd_state(se_cmd));
2648 
2649 		spin_lock_irqsave(&se_cmd->t_state_lock, flags);
2650 		tas = (se_cmd->transport_state & CMD_T_TAS);
2651 		spin_unlock_irqrestore(&se_cmd->t_state_lock, flags);
2652 
2653 		if (!target_put_sess_cmd(se_cmd)) {
2654 			if (tas)
2655 				target_put_sess_cmd(se_cmd);
2656 		}
2657 
2658 		wait_for_completion(&se_cmd->cmd_wait_comp);
2659 		pr_debug("After cmd_wait_comp: se_cmd: %p t_state: %d"
2660 			" fabric state: %d\n", se_cmd, se_cmd->t_state,
2661 			se_cmd->se_tfo->get_cmd_state(se_cmd));
2662 
2663 		se_cmd->se_tfo->release_cmd(se_cmd);
2664 	}
2665 
2666 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2667 	WARN_ON(!list_empty(&se_sess->sess_cmd_list));
2668 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2669 
2670 }
2671 EXPORT_SYMBOL(target_wait_for_sess_cmds);
2672 
2673 void transport_clear_lun_ref(struct se_lun *lun)
2674 {
2675 	percpu_ref_kill(&lun->lun_ref);
2676 	wait_for_completion(&lun->lun_ref_comp);
2677 }
2678 
2679 static bool
2680 __transport_wait_for_tasks(struct se_cmd *cmd, bool fabric_stop,
2681 			   bool *aborted, bool *tas, unsigned long *flags)
2682 	__releases(&cmd->t_state_lock)
2683 	__acquires(&cmd->t_state_lock)
2684 {
2685 
2686 	assert_spin_locked(&cmd->t_state_lock);
2687 	WARN_ON_ONCE(!irqs_disabled());
2688 
2689 	if (fabric_stop)
2690 		cmd->transport_state |= CMD_T_FABRIC_STOP;
2691 
2692 	if (cmd->transport_state & CMD_T_ABORTED)
2693 		*aborted = true;
2694 
2695 	if (cmd->transport_state & CMD_T_TAS)
2696 		*tas = true;
2697 
2698 	if (!(cmd->se_cmd_flags & SCF_SE_LUN_CMD) &&
2699 	    !(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
2700 		return false;
2701 
2702 	if (!(cmd->se_cmd_flags & SCF_SUPPORTED_SAM_OPCODE) &&
2703 	    !(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
2704 		return false;
2705 
2706 	if (!(cmd->transport_state & CMD_T_ACTIVE))
2707 		return false;
2708 
2709 	if (fabric_stop && *aborted)
2710 		return false;
2711 
2712 	cmd->transport_state |= CMD_T_STOP;
2713 
2714 	pr_debug("wait_for_tasks: Stopping %p ITT: 0x%08llx i_state: %d,"
2715 		 " t_state: %d, CMD_T_STOP\n", cmd, cmd->tag,
2716 		 cmd->se_tfo->get_cmd_state(cmd), cmd->t_state);
2717 
2718 	spin_unlock_irqrestore(&cmd->t_state_lock, *flags);
2719 
2720 	wait_for_completion(&cmd->t_transport_stop_comp);
2721 
2722 	spin_lock_irqsave(&cmd->t_state_lock, *flags);
2723 	cmd->transport_state &= ~(CMD_T_ACTIVE | CMD_T_STOP);
2724 
2725 	pr_debug("wait_for_tasks: Stopped wait_for_completion(&cmd->"
2726 		 "t_transport_stop_comp) for ITT: 0x%08llx\n", cmd->tag);
2727 
2728 	return true;
2729 }
2730 
2731 /**
2732  * transport_wait_for_tasks - wait for completion to occur
2733  * @cmd:	command to wait
2734  *
2735  * Called from frontend fabric context to wait for storage engine
2736  * to pause and/or release frontend generated struct se_cmd.
2737  */
2738 bool transport_wait_for_tasks(struct se_cmd *cmd)
2739 {
2740 	unsigned long flags;
2741 	bool ret, aborted = false, tas = false;
2742 
2743 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2744 	ret = __transport_wait_for_tasks(cmd, false, &aborted, &tas, &flags);
2745 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2746 
2747 	return ret;
2748 }
2749 EXPORT_SYMBOL(transport_wait_for_tasks);
2750 
2751 struct sense_info {
2752 	u8 key;
2753 	u8 asc;
2754 	u8 ascq;
2755 	bool add_sector_info;
2756 };
2757 
2758 static const struct sense_info sense_info_table[] = {
2759 	[TCM_NO_SENSE] = {
2760 		.key = NOT_READY
2761 	},
2762 	[TCM_NON_EXISTENT_LUN] = {
2763 		.key = ILLEGAL_REQUEST,
2764 		.asc = 0x25 /* LOGICAL UNIT NOT SUPPORTED */
2765 	},
2766 	[TCM_UNSUPPORTED_SCSI_OPCODE] = {
2767 		.key = ILLEGAL_REQUEST,
2768 		.asc = 0x20, /* INVALID COMMAND OPERATION CODE */
2769 	},
2770 	[TCM_SECTOR_COUNT_TOO_MANY] = {
2771 		.key = ILLEGAL_REQUEST,
2772 		.asc = 0x20, /* INVALID COMMAND OPERATION CODE */
2773 	},
2774 	[TCM_UNKNOWN_MODE_PAGE] = {
2775 		.key = ILLEGAL_REQUEST,
2776 		.asc = 0x24, /* INVALID FIELD IN CDB */
2777 	},
2778 	[TCM_CHECK_CONDITION_ABORT_CMD] = {
2779 		.key = ABORTED_COMMAND,
2780 		.asc = 0x29, /* BUS DEVICE RESET FUNCTION OCCURRED */
2781 		.ascq = 0x03,
2782 	},
2783 	[TCM_INCORRECT_AMOUNT_OF_DATA] = {
2784 		.key = ABORTED_COMMAND,
2785 		.asc = 0x0c, /* WRITE ERROR */
2786 		.ascq = 0x0d, /* NOT ENOUGH UNSOLICITED DATA */
2787 	},
2788 	[TCM_INVALID_CDB_FIELD] = {
2789 		.key = ILLEGAL_REQUEST,
2790 		.asc = 0x24, /* INVALID FIELD IN CDB */
2791 	},
2792 	[TCM_INVALID_PARAMETER_LIST] = {
2793 		.key = ILLEGAL_REQUEST,
2794 		.asc = 0x26, /* INVALID FIELD IN PARAMETER LIST */
2795 	},
2796 	[TCM_PARAMETER_LIST_LENGTH_ERROR] = {
2797 		.key = ILLEGAL_REQUEST,
2798 		.asc = 0x1a, /* PARAMETER LIST LENGTH ERROR */
2799 	},
2800 	[TCM_UNEXPECTED_UNSOLICITED_DATA] = {
2801 		.key = ILLEGAL_REQUEST,
2802 		.asc = 0x0c, /* WRITE ERROR */
2803 		.ascq = 0x0c, /* UNEXPECTED_UNSOLICITED_DATA */
2804 	},
2805 	[TCM_SERVICE_CRC_ERROR] = {
2806 		.key = ABORTED_COMMAND,
2807 		.asc = 0x47, /* PROTOCOL SERVICE CRC ERROR */
2808 		.ascq = 0x05, /* N/A */
2809 	},
2810 	[TCM_SNACK_REJECTED] = {
2811 		.key = ABORTED_COMMAND,
2812 		.asc = 0x11, /* READ ERROR */
2813 		.ascq = 0x13, /* FAILED RETRANSMISSION REQUEST */
2814 	},
2815 	[TCM_WRITE_PROTECTED] = {
2816 		.key = DATA_PROTECT,
2817 		.asc = 0x27, /* WRITE PROTECTED */
2818 	},
2819 	[TCM_ADDRESS_OUT_OF_RANGE] = {
2820 		.key = ILLEGAL_REQUEST,
2821 		.asc = 0x21, /* LOGICAL BLOCK ADDRESS OUT OF RANGE */
2822 	},
2823 	[TCM_CHECK_CONDITION_UNIT_ATTENTION] = {
2824 		.key = UNIT_ATTENTION,
2825 	},
2826 	[TCM_CHECK_CONDITION_NOT_READY] = {
2827 		.key = NOT_READY,
2828 	},
2829 	[TCM_MISCOMPARE_VERIFY] = {
2830 		.key = MISCOMPARE,
2831 		.asc = 0x1d, /* MISCOMPARE DURING VERIFY OPERATION */
2832 		.ascq = 0x00,
2833 	},
2834 	[TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED] = {
2835 		.key = ABORTED_COMMAND,
2836 		.asc = 0x10,
2837 		.ascq = 0x01, /* LOGICAL BLOCK GUARD CHECK FAILED */
2838 		.add_sector_info = true,
2839 	},
2840 	[TCM_LOGICAL_BLOCK_APP_TAG_CHECK_FAILED] = {
2841 		.key = ABORTED_COMMAND,
2842 		.asc = 0x10,
2843 		.ascq = 0x02, /* LOGICAL BLOCK APPLICATION TAG CHECK FAILED */
2844 		.add_sector_info = true,
2845 	},
2846 	[TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED] = {
2847 		.key = ABORTED_COMMAND,
2848 		.asc = 0x10,
2849 		.ascq = 0x03, /* LOGICAL BLOCK REFERENCE TAG CHECK FAILED */
2850 		.add_sector_info = true,
2851 	},
2852 	[TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE] = {
2853 		/*
2854 		 * Returning ILLEGAL REQUEST would cause immediate IO errors on
2855 		 * Solaris initiators.  Returning NOT READY instead means the
2856 		 * operations will be retried a finite number of times and we
2857 		 * can survive intermittent errors.
2858 		 */
2859 		.key = NOT_READY,
2860 		.asc = 0x08, /* LOGICAL UNIT COMMUNICATION FAILURE */
2861 	},
2862 };
2863 
2864 static int translate_sense_reason(struct se_cmd *cmd, sense_reason_t reason)
2865 {
2866 	const struct sense_info *si;
2867 	u8 *buffer = cmd->sense_buffer;
2868 	int r = (__force int)reason;
2869 	u8 asc, ascq;
2870 	bool desc_format = target_sense_desc_format(cmd->se_dev);
2871 
2872 	if (r < ARRAY_SIZE(sense_info_table) && sense_info_table[r].key)
2873 		si = &sense_info_table[r];
2874 	else
2875 		si = &sense_info_table[(__force int)
2876 				       TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE];
2877 
2878 	if (reason == TCM_CHECK_CONDITION_UNIT_ATTENTION) {
2879 		core_scsi3_ua_for_check_condition(cmd, &asc, &ascq);
2880 		WARN_ON_ONCE(asc == 0);
2881 	} else if (si->asc == 0) {
2882 		WARN_ON_ONCE(cmd->scsi_asc == 0);
2883 		asc = cmd->scsi_asc;
2884 		ascq = cmd->scsi_ascq;
2885 	} else {
2886 		asc = si->asc;
2887 		ascq = si->ascq;
2888 	}
2889 
2890 	scsi_build_sense_buffer(desc_format, buffer, si->key, asc, ascq);
2891 	if (si->add_sector_info)
2892 		return scsi_set_sense_information(buffer,
2893 						  cmd->scsi_sense_length,
2894 						  cmd->bad_sector);
2895 
2896 	return 0;
2897 }
2898 
2899 int
2900 transport_send_check_condition_and_sense(struct se_cmd *cmd,
2901 		sense_reason_t reason, int from_transport)
2902 {
2903 	unsigned long flags;
2904 
2905 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2906 	if (cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION) {
2907 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2908 		return 0;
2909 	}
2910 	cmd->se_cmd_flags |= SCF_SENT_CHECK_CONDITION;
2911 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2912 
2913 	if (!from_transport) {
2914 		int rc;
2915 
2916 		cmd->se_cmd_flags |= SCF_EMULATED_TASK_SENSE;
2917 		cmd->scsi_status = SAM_STAT_CHECK_CONDITION;
2918 		cmd->scsi_sense_length  = TRANSPORT_SENSE_BUFFER;
2919 		rc = translate_sense_reason(cmd, reason);
2920 		if (rc)
2921 			return rc;
2922 	}
2923 
2924 	trace_target_cmd_complete(cmd);
2925 	return cmd->se_tfo->queue_status(cmd);
2926 }
2927 EXPORT_SYMBOL(transport_send_check_condition_and_sense);
2928 
2929 static int __transport_check_aborted_status(struct se_cmd *cmd, int send_status)
2930 	__releases(&cmd->t_state_lock)
2931 	__acquires(&cmd->t_state_lock)
2932 {
2933 	assert_spin_locked(&cmd->t_state_lock);
2934 	WARN_ON_ONCE(!irqs_disabled());
2935 
2936 	if (!(cmd->transport_state & CMD_T_ABORTED))
2937 		return 0;
2938 	/*
2939 	 * If cmd has been aborted but either no status is to be sent or it has
2940 	 * already been sent, just return
2941 	 */
2942 	if (!send_status || !(cmd->se_cmd_flags & SCF_SEND_DELAYED_TAS)) {
2943 		if (send_status)
2944 			cmd->se_cmd_flags |= SCF_SEND_DELAYED_TAS;
2945 		return 1;
2946 	}
2947 
2948 	pr_debug("Sending delayed SAM_STAT_TASK_ABORTED status for CDB:"
2949 		" 0x%02x ITT: 0x%08llx\n", cmd->t_task_cdb[0], cmd->tag);
2950 
2951 	cmd->se_cmd_flags &= ~SCF_SEND_DELAYED_TAS;
2952 	cmd->scsi_status = SAM_STAT_TASK_ABORTED;
2953 	trace_target_cmd_complete(cmd);
2954 
2955 	spin_unlock_irq(&cmd->t_state_lock);
2956 	cmd->se_tfo->queue_status(cmd);
2957 	spin_lock_irq(&cmd->t_state_lock);
2958 
2959 	return 1;
2960 }
2961 
2962 int transport_check_aborted_status(struct se_cmd *cmd, int send_status)
2963 {
2964 	int ret;
2965 
2966 	spin_lock_irq(&cmd->t_state_lock);
2967 	ret = __transport_check_aborted_status(cmd, send_status);
2968 	spin_unlock_irq(&cmd->t_state_lock);
2969 
2970 	return ret;
2971 }
2972 EXPORT_SYMBOL(transport_check_aborted_status);
2973 
2974 void transport_send_task_abort(struct se_cmd *cmd)
2975 {
2976 	unsigned long flags;
2977 
2978 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2979 	if (cmd->se_cmd_flags & (SCF_SENT_CHECK_CONDITION)) {
2980 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2981 		return;
2982 	}
2983 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2984 
2985 	/*
2986 	 * If there are still expected incoming fabric WRITEs, we wait
2987 	 * until until they have completed before sending a TASK_ABORTED
2988 	 * response.  This response with TASK_ABORTED status will be
2989 	 * queued back to fabric module by transport_check_aborted_status().
2990 	 */
2991 	if (cmd->data_direction == DMA_TO_DEVICE) {
2992 		if (cmd->se_tfo->write_pending_status(cmd) != 0) {
2993 			spin_lock_irqsave(&cmd->t_state_lock, flags);
2994 			if (cmd->se_cmd_flags & SCF_SEND_DELAYED_TAS) {
2995 				spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2996 				goto send_abort;
2997 			}
2998 			cmd->se_cmd_flags |= SCF_SEND_DELAYED_TAS;
2999 			spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3000 			return;
3001 		}
3002 	}
3003 send_abort:
3004 	cmd->scsi_status = SAM_STAT_TASK_ABORTED;
3005 
3006 	transport_lun_remove_cmd(cmd);
3007 
3008 	pr_debug("Setting SAM_STAT_TASK_ABORTED status for CDB: 0x%02x, ITT: 0x%08llx\n",
3009 		 cmd->t_task_cdb[0], cmd->tag);
3010 
3011 	trace_target_cmd_complete(cmd);
3012 	cmd->se_tfo->queue_status(cmd);
3013 }
3014 
3015 static void target_tmr_work(struct work_struct *work)
3016 {
3017 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
3018 	struct se_device *dev = cmd->se_dev;
3019 	struct se_tmr_req *tmr = cmd->se_tmr_req;
3020 	unsigned long flags;
3021 	int ret;
3022 
3023 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3024 	if (cmd->transport_state & CMD_T_ABORTED) {
3025 		tmr->response = TMR_FUNCTION_REJECTED;
3026 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3027 		goto check_stop;
3028 	}
3029 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3030 
3031 	switch (tmr->function) {
3032 	case TMR_ABORT_TASK:
3033 		core_tmr_abort_task(dev, tmr, cmd->se_sess);
3034 		break;
3035 	case TMR_ABORT_TASK_SET:
3036 	case TMR_CLEAR_ACA:
3037 	case TMR_CLEAR_TASK_SET:
3038 		tmr->response = TMR_TASK_MGMT_FUNCTION_NOT_SUPPORTED;
3039 		break;
3040 	case TMR_LUN_RESET:
3041 		ret = core_tmr_lun_reset(dev, tmr, NULL, NULL);
3042 		tmr->response = (!ret) ? TMR_FUNCTION_COMPLETE :
3043 					 TMR_FUNCTION_REJECTED;
3044 		if (tmr->response == TMR_FUNCTION_COMPLETE) {
3045 			target_ua_allocate_lun(cmd->se_sess->se_node_acl,
3046 					       cmd->orig_fe_lun, 0x29,
3047 					       ASCQ_29H_BUS_DEVICE_RESET_FUNCTION_OCCURRED);
3048 		}
3049 		break;
3050 	case TMR_TARGET_WARM_RESET:
3051 		tmr->response = TMR_FUNCTION_REJECTED;
3052 		break;
3053 	case TMR_TARGET_COLD_RESET:
3054 		tmr->response = TMR_FUNCTION_REJECTED;
3055 		break;
3056 	default:
3057 		pr_err("Uknown TMR function: 0x%02x.\n",
3058 				tmr->function);
3059 		tmr->response = TMR_FUNCTION_REJECTED;
3060 		break;
3061 	}
3062 
3063 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3064 	if (cmd->transport_state & CMD_T_ABORTED) {
3065 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3066 		goto check_stop;
3067 	}
3068 	cmd->t_state = TRANSPORT_ISTATE_PROCESSING;
3069 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3070 
3071 	cmd->se_tfo->queue_tm_rsp(cmd);
3072 
3073 check_stop:
3074 	transport_cmd_check_stop_to_fabric(cmd);
3075 }
3076 
3077 int transport_generic_handle_tmr(
3078 	struct se_cmd *cmd)
3079 {
3080 	unsigned long flags;
3081 
3082 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3083 	cmd->transport_state |= CMD_T_ACTIVE;
3084 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3085 
3086 	INIT_WORK(&cmd->work, target_tmr_work);
3087 	queue_work(cmd->se_dev->tmr_wq, &cmd->work);
3088 	return 0;
3089 }
3090 EXPORT_SYMBOL(transport_generic_handle_tmr);
3091 
3092 bool
3093 target_check_wce(struct se_device *dev)
3094 {
3095 	bool wce = false;
3096 
3097 	if (dev->transport->get_write_cache)
3098 		wce = dev->transport->get_write_cache(dev);
3099 	else if (dev->dev_attrib.emulate_write_cache > 0)
3100 		wce = true;
3101 
3102 	return wce;
3103 }
3104 
3105 bool
3106 target_check_fua(struct se_device *dev)
3107 {
3108 	return target_check_wce(dev) && dev->dev_attrib.emulate_fua_write > 0;
3109 }
3110