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