xref: /linux/drivers/target/target_core_transport.c (revision 55f3538c4923e9dfca132e99ebec370e8094afda)
1 /*******************************************************************************
2  * Filename:  target_core_transport.c
3  *
4  * This file contains the Generic Target Engine Core.
5  *
6  * (c) Copyright 2002-2013 Datera, Inc.
7  *
8  * Nicholas A. Bellinger <nab@kernel.org>
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License as published by
12  * the Free Software Foundation; either version 2 of the License, or
13  * (at your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18  * GNU General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with this program; if not, write to the Free Software
22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
23  *
24  ******************************************************************************/
25 
26 #include <linux/net.h>
27 #include <linux/delay.h>
28 #include <linux/string.h>
29 #include <linux/timer.h>
30 #include <linux/slab.h>
31 #include <linux/spinlock.h>
32 #include <linux/kthread.h>
33 #include <linux/in.h>
34 #include <linux/cdrom.h>
35 #include <linux/module.h>
36 #include <linux/ratelimit.h>
37 #include <linux/vmalloc.h>
38 #include <asm/unaligned.h>
39 #include <net/sock.h>
40 #include <net/tcp.h>
41 #include <scsi/scsi_proto.h>
42 #include <scsi/scsi_common.h>
43 
44 #include <target/target_core_base.h>
45 #include <target/target_core_backend.h>
46 #include <target/target_core_fabric.h>
47 
48 #include "target_core_internal.h"
49 #include "target_core_alua.h"
50 #include "target_core_pr.h"
51 #include "target_core_ua.h"
52 
53 #define CREATE_TRACE_POINTS
54 #include <trace/events/target.h>
55 
56 static struct workqueue_struct *target_completion_wq;
57 static struct kmem_cache *se_sess_cache;
58 struct kmem_cache *se_ua_cache;
59 struct kmem_cache *t10_pr_reg_cache;
60 struct kmem_cache *t10_alua_lu_gp_cache;
61 struct kmem_cache *t10_alua_lu_gp_mem_cache;
62 struct kmem_cache *t10_alua_tg_pt_gp_cache;
63 struct kmem_cache *t10_alua_lba_map_cache;
64 struct kmem_cache *t10_alua_lba_map_mem_cache;
65 
66 static void transport_complete_task_attr(struct se_cmd *cmd);
67 static int translate_sense_reason(struct se_cmd *cmd, sense_reason_t reason);
68 static void transport_handle_queue_full(struct se_cmd *cmd,
69 		struct se_device *dev, int err, bool write_pending);
70 static 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_RETRY_MAYFAIL);
255 	if (!se_sess->sess_cmd_map) {
256 		se_sess->sess_cmd_map = vzalloc(tag_num * tag_size);
257 		if (!se_sess->sess_cmd_map) {
258 			pr_err("Unable to allocate se_sess->sess_cmd_map\n");
259 			return -ENOMEM;
260 		}
261 	}
262 
263 	rc = percpu_ida_init(&se_sess->sess_tag_pool, tag_num);
264 	if (rc < 0) {
265 		pr_err("Unable to init se_sess->sess_tag_pool,"
266 			" tag_num: %u\n", tag_num);
267 		kvfree(se_sess->sess_cmd_map);
268 		se_sess->sess_cmd_map = NULL;
269 		return -ENOMEM;
270 	}
271 
272 	return 0;
273 }
274 EXPORT_SYMBOL(transport_alloc_session_tags);
275 
276 struct se_session *transport_init_session_tags(unsigned int tag_num,
277 					       unsigned int tag_size,
278 					       enum target_prot_op sup_prot_ops)
279 {
280 	struct se_session *se_sess;
281 	int rc;
282 
283 	if (tag_num != 0 && !tag_size) {
284 		pr_err("init_session_tags called with percpu-ida tag_num:"
285 		       " %u, but zero tag_size\n", tag_num);
286 		return ERR_PTR(-EINVAL);
287 	}
288 	if (!tag_num && tag_size) {
289 		pr_err("init_session_tags called with percpu-ida tag_size:"
290 		       " %u, but zero tag_num\n", tag_size);
291 		return ERR_PTR(-EINVAL);
292 	}
293 
294 	se_sess = transport_init_session(sup_prot_ops);
295 	if (IS_ERR(se_sess))
296 		return se_sess;
297 
298 	rc = transport_alloc_session_tags(se_sess, tag_num, tag_size);
299 	if (rc < 0) {
300 		transport_free_session(se_sess);
301 		return ERR_PTR(-ENOMEM);
302 	}
303 
304 	return se_sess;
305 }
306 EXPORT_SYMBOL(transport_init_session_tags);
307 
308 /*
309  * Called with spin_lock_irqsave(&struct se_portal_group->session_lock called.
310  */
311 void __transport_register_session(
312 	struct se_portal_group *se_tpg,
313 	struct se_node_acl *se_nacl,
314 	struct se_session *se_sess,
315 	void *fabric_sess_ptr)
316 {
317 	const struct target_core_fabric_ops *tfo = se_tpg->se_tpg_tfo;
318 	unsigned char buf[PR_REG_ISID_LEN];
319 
320 	se_sess->se_tpg = se_tpg;
321 	se_sess->fabric_sess_ptr = fabric_sess_ptr;
322 	/*
323 	 * Used by struct se_node_acl's under ConfigFS to locate active se_session-t
324 	 *
325 	 * Only set for struct se_session's that will actually be moving I/O.
326 	 * eg: *NOT* discovery sessions.
327 	 */
328 	if (se_nacl) {
329 		/*
330 		 *
331 		 * Determine if fabric allows for T10-PI feature bits exposed to
332 		 * initiators for device backends with !dev->dev_attrib.pi_prot_type.
333 		 *
334 		 * If so, then always save prot_type on a per se_node_acl node
335 		 * basis and re-instate the previous sess_prot_type to avoid
336 		 * disabling PI from below any previously initiator side
337 		 * registered LUNs.
338 		 */
339 		if (se_nacl->saved_prot_type)
340 			se_sess->sess_prot_type = se_nacl->saved_prot_type;
341 		else if (tfo->tpg_check_prot_fabric_only)
342 			se_sess->sess_prot_type = se_nacl->saved_prot_type =
343 					tfo->tpg_check_prot_fabric_only(se_tpg);
344 		/*
345 		 * If the fabric module supports an ISID based TransportID,
346 		 * save this value in binary from the fabric I_T Nexus now.
347 		 */
348 		if (se_tpg->se_tpg_tfo->sess_get_initiator_sid != NULL) {
349 			memset(&buf[0], 0, PR_REG_ISID_LEN);
350 			se_tpg->se_tpg_tfo->sess_get_initiator_sid(se_sess,
351 					&buf[0], PR_REG_ISID_LEN);
352 			se_sess->sess_bin_isid = get_unaligned_be64(&buf[0]);
353 		}
354 
355 		spin_lock_irq(&se_nacl->nacl_sess_lock);
356 		/*
357 		 * The se_nacl->nacl_sess pointer will be set to the
358 		 * last active I_T Nexus for each struct se_node_acl.
359 		 */
360 		se_nacl->nacl_sess = se_sess;
361 
362 		list_add_tail(&se_sess->sess_acl_list,
363 			      &se_nacl->acl_sess_list);
364 		spin_unlock_irq(&se_nacl->nacl_sess_lock);
365 	}
366 	list_add_tail(&se_sess->sess_list, &se_tpg->tpg_sess_list);
367 
368 	pr_debug("TARGET_CORE[%s]: Registered fabric_sess_ptr: %p\n",
369 		se_tpg->se_tpg_tfo->get_fabric_name(), se_sess->fabric_sess_ptr);
370 }
371 EXPORT_SYMBOL(__transport_register_session);
372 
373 void transport_register_session(
374 	struct se_portal_group *se_tpg,
375 	struct se_node_acl *se_nacl,
376 	struct se_session *se_sess,
377 	void *fabric_sess_ptr)
378 {
379 	unsigned long flags;
380 
381 	spin_lock_irqsave(&se_tpg->session_lock, flags);
382 	__transport_register_session(se_tpg, se_nacl, se_sess, fabric_sess_ptr);
383 	spin_unlock_irqrestore(&se_tpg->session_lock, flags);
384 }
385 EXPORT_SYMBOL(transport_register_session);
386 
387 struct se_session *
388 target_alloc_session(struct se_portal_group *tpg,
389 		     unsigned int tag_num, unsigned int tag_size,
390 		     enum target_prot_op prot_op,
391 		     const char *initiatorname, void *private,
392 		     int (*callback)(struct se_portal_group *,
393 				     struct se_session *, void *))
394 {
395 	struct se_session *sess;
396 
397 	/*
398 	 * If the fabric driver is using percpu-ida based pre allocation
399 	 * of I/O descriptor tags, go ahead and perform that setup now..
400 	 */
401 	if (tag_num != 0)
402 		sess = transport_init_session_tags(tag_num, tag_size, prot_op);
403 	else
404 		sess = transport_init_session(prot_op);
405 
406 	if (IS_ERR(sess))
407 		return sess;
408 
409 	sess->se_node_acl = core_tpg_check_initiator_node_acl(tpg,
410 					(unsigned char *)initiatorname);
411 	if (!sess->se_node_acl) {
412 		transport_free_session(sess);
413 		return ERR_PTR(-EACCES);
414 	}
415 	/*
416 	 * Go ahead and perform any remaining fabric setup that is
417 	 * required before transport_register_session().
418 	 */
419 	if (callback != NULL) {
420 		int rc = callback(tpg, sess, private);
421 		if (rc) {
422 			transport_free_session(sess);
423 			return ERR_PTR(rc);
424 		}
425 	}
426 
427 	transport_register_session(tpg, sess->se_node_acl, sess, private);
428 	return sess;
429 }
430 EXPORT_SYMBOL(target_alloc_session);
431 
432 ssize_t target_show_dynamic_sessions(struct se_portal_group *se_tpg, char *page)
433 {
434 	struct se_session *se_sess;
435 	ssize_t len = 0;
436 
437 	spin_lock_bh(&se_tpg->session_lock);
438 	list_for_each_entry(se_sess, &se_tpg->tpg_sess_list, sess_list) {
439 		if (!se_sess->se_node_acl)
440 			continue;
441 		if (!se_sess->se_node_acl->dynamic_node_acl)
442 			continue;
443 		if (strlen(se_sess->se_node_acl->initiatorname) + 1 + len > PAGE_SIZE)
444 			break;
445 
446 		len += snprintf(page + len, PAGE_SIZE - len, "%s\n",
447 				se_sess->se_node_acl->initiatorname);
448 		len += 1; /* Include NULL terminator */
449 	}
450 	spin_unlock_bh(&se_tpg->session_lock);
451 
452 	return len;
453 }
454 EXPORT_SYMBOL(target_show_dynamic_sessions);
455 
456 static void target_complete_nacl(struct kref *kref)
457 {
458 	struct se_node_acl *nacl = container_of(kref,
459 				struct se_node_acl, acl_kref);
460 	struct se_portal_group *se_tpg = nacl->se_tpg;
461 
462 	if (!nacl->dynamic_stop) {
463 		complete(&nacl->acl_free_comp);
464 		return;
465 	}
466 
467 	mutex_lock(&se_tpg->acl_node_mutex);
468 	list_del_init(&nacl->acl_list);
469 	mutex_unlock(&se_tpg->acl_node_mutex);
470 
471 	core_tpg_wait_for_nacl_pr_ref(nacl);
472 	core_free_device_list_for_node(nacl, se_tpg);
473 	kfree(nacl);
474 }
475 
476 void target_put_nacl(struct se_node_acl *nacl)
477 {
478 	kref_put(&nacl->acl_kref, target_complete_nacl);
479 }
480 EXPORT_SYMBOL(target_put_nacl);
481 
482 void transport_deregister_session_configfs(struct se_session *se_sess)
483 {
484 	struct se_node_acl *se_nacl;
485 	unsigned long flags;
486 	/*
487 	 * Used by struct se_node_acl's under ConfigFS to locate active struct se_session
488 	 */
489 	se_nacl = se_sess->se_node_acl;
490 	if (se_nacl) {
491 		spin_lock_irqsave(&se_nacl->nacl_sess_lock, flags);
492 		if (!list_empty(&se_sess->sess_acl_list))
493 			list_del_init(&se_sess->sess_acl_list);
494 		/*
495 		 * If the session list is empty, then clear the pointer.
496 		 * Otherwise, set the struct se_session pointer from the tail
497 		 * element of the per struct se_node_acl active session list.
498 		 */
499 		if (list_empty(&se_nacl->acl_sess_list))
500 			se_nacl->nacl_sess = NULL;
501 		else {
502 			se_nacl->nacl_sess = container_of(
503 					se_nacl->acl_sess_list.prev,
504 					struct se_session, sess_acl_list);
505 		}
506 		spin_unlock_irqrestore(&se_nacl->nacl_sess_lock, flags);
507 	}
508 }
509 EXPORT_SYMBOL(transport_deregister_session_configfs);
510 
511 void transport_free_session(struct se_session *se_sess)
512 {
513 	struct se_node_acl *se_nacl = se_sess->se_node_acl;
514 
515 	/*
516 	 * Drop the se_node_acl->nacl_kref obtained from within
517 	 * core_tpg_get_initiator_node_acl().
518 	 */
519 	if (se_nacl) {
520 		struct se_portal_group *se_tpg = se_nacl->se_tpg;
521 		const struct target_core_fabric_ops *se_tfo = se_tpg->se_tpg_tfo;
522 		unsigned long flags;
523 
524 		se_sess->se_node_acl = NULL;
525 
526 		/*
527 		 * Also determine if we need to drop the extra ->cmd_kref if
528 		 * it had been previously dynamically generated, and
529 		 * the endpoint is not caching dynamic ACLs.
530 		 */
531 		mutex_lock(&se_tpg->acl_node_mutex);
532 		if (se_nacl->dynamic_node_acl &&
533 		    !se_tfo->tpg_check_demo_mode_cache(se_tpg)) {
534 			spin_lock_irqsave(&se_nacl->nacl_sess_lock, flags);
535 			if (list_empty(&se_nacl->acl_sess_list))
536 				se_nacl->dynamic_stop = true;
537 			spin_unlock_irqrestore(&se_nacl->nacl_sess_lock, flags);
538 
539 			if (se_nacl->dynamic_stop)
540 				list_del_init(&se_nacl->acl_list);
541 		}
542 		mutex_unlock(&se_tpg->acl_node_mutex);
543 
544 		if (se_nacl->dynamic_stop)
545 			target_put_nacl(se_nacl);
546 
547 		target_put_nacl(se_nacl);
548 	}
549 	if (se_sess->sess_cmd_map) {
550 		percpu_ida_destroy(&se_sess->sess_tag_pool);
551 		kvfree(se_sess->sess_cmd_map);
552 	}
553 	kmem_cache_free(se_sess_cache, se_sess);
554 }
555 EXPORT_SYMBOL(transport_free_session);
556 
557 void transport_deregister_session(struct se_session *se_sess)
558 {
559 	struct se_portal_group *se_tpg = se_sess->se_tpg;
560 	unsigned long flags;
561 
562 	if (!se_tpg) {
563 		transport_free_session(se_sess);
564 		return;
565 	}
566 
567 	spin_lock_irqsave(&se_tpg->session_lock, flags);
568 	list_del(&se_sess->sess_list);
569 	se_sess->se_tpg = NULL;
570 	se_sess->fabric_sess_ptr = NULL;
571 	spin_unlock_irqrestore(&se_tpg->session_lock, flags);
572 
573 	pr_debug("TARGET_CORE[%s]: Deregistered fabric_sess\n",
574 		se_tpg->se_tpg_tfo->get_fabric_name());
575 	/*
576 	 * If last kref is dropping now for an explicit NodeACL, awake sleeping
577 	 * ->acl_free_comp caller to wakeup configfs se_node_acl->acl_group
578 	 * removal context from within transport_free_session() code.
579 	 *
580 	 * For dynamic ACL, target_put_nacl() uses target_complete_nacl()
581 	 * to release all remaining generate_node_acl=1 created ACL resources.
582 	 */
583 
584 	transport_free_session(se_sess);
585 }
586 EXPORT_SYMBOL(transport_deregister_session);
587 
588 static void target_remove_from_state_list(struct se_cmd *cmd)
589 {
590 	struct se_device *dev = cmd->se_dev;
591 	unsigned long flags;
592 
593 	if (!dev)
594 		return;
595 
596 	spin_lock_irqsave(&dev->execute_task_lock, flags);
597 	if (cmd->state_active) {
598 		list_del(&cmd->state_list);
599 		cmd->state_active = false;
600 	}
601 	spin_unlock_irqrestore(&dev->execute_task_lock, flags);
602 }
603 
604 static int transport_cmd_check_stop_to_fabric(struct se_cmd *cmd)
605 {
606 	unsigned long flags;
607 
608 	target_remove_from_state_list(cmd);
609 
610 	/*
611 	 * Clear struct se_cmd->se_lun before the handoff to FE.
612 	 */
613 	cmd->se_lun = NULL;
614 
615 	spin_lock_irqsave(&cmd->t_state_lock, flags);
616 	/*
617 	 * Determine if frontend context caller is requesting the stopping of
618 	 * this command for frontend exceptions.
619 	 */
620 	if (cmd->transport_state & CMD_T_STOP) {
621 		pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08llx\n",
622 			__func__, __LINE__, cmd->tag);
623 
624 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
625 
626 		complete_all(&cmd->t_transport_stop_comp);
627 		return 1;
628 	}
629 	cmd->transport_state &= ~CMD_T_ACTIVE;
630 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
631 
632 	/*
633 	 * Some fabric modules like tcm_loop can release their internally
634 	 * allocated I/O reference and struct se_cmd now.
635 	 *
636 	 * Fabric modules are expected to return '1' here if the se_cmd being
637 	 * passed is released at this point, or zero if not being released.
638 	 */
639 	return cmd->se_tfo->check_stop_free(cmd);
640 }
641 
642 static void transport_lun_remove_cmd(struct se_cmd *cmd)
643 {
644 	struct se_lun *lun = cmd->se_lun;
645 
646 	if (!lun)
647 		return;
648 
649 	if (cmpxchg(&cmd->lun_ref_active, true, false))
650 		percpu_ref_put(&lun->lun_ref);
651 }
652 
653 int transport_cmd_finish_abort(struct se_cmd *cmd, int remove)
654 {
655 	bool ack_kref = (cmd->se_cmd_flags & SCF_ACK_KREF);
656 	int ret = 0;
657 
658 	if (cmd->se_cmd_flags & SCF_SE_LUN_CMD)
659 		transport_lun_remove_cmd(cmd);
660 	/*
661 	 * Allow the fabric driver to unmap any resources before
662 	 * releasing the descriptor via TFO->release_cmd()
663 	 */
664 	if (remove)
665 		cmd->se_tfo->aborted_task(cmd);
666 
667 	if (transport_cmd_check_stop_to_fabric(cmd))
668 		return 1;
669 	if (remove && ack_kref)
670 		ret = target_put_sess_cmd(cmd);
671 
672 	return ret;
673 }
674 
675 static void target_complete_failure_work(struct work_struct *work)
676 {
677 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
678 
679 	transport_generic_request_failure(cmd,
680 			TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE);
681 }
682 
683 /*
684  * Used when asking transport to copy Sense Data from the underlying
685  * Linux/SCSI struct scsi_cmnd
686  */
687 static unsigned char *transport_get_sense_buffer(struct se_cmd *cmd)
688 {
689 	struct se_device *dev = cmd->se_dev;
690 
691 	WARN_ON(!cmd->se_lun);
692 
693 	if (!dev)
694 		return NULL;
695 
696 	if (cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION)
697 		return NULL;
698 
699 	cmd->scsi_sense_length = TRANSPORT_SENSE_BUFFER;
700 
701 	pr_debug("HBA_[%u]_PLUG[%s]: Requesting sense for SAM STATUS: 0x%02x\n",
702 		dev->se_hba->hba_id, dev->transport->name, cmd->scsi_status);
703 	return cmd->sense_buffer;
704 }
705 
706 void transport_copy_sense_to_cmd(struct se_cmd *cmd, unsigned char *sense)
707 {
708 	unsigned char *cmd_sense_buf;
709 	unsigned long flags;
710 
711 	spin_lock_irqsave(&cmd->t_state_lock, flags);
712 	cmd_sense_buf = transport_get_sense_buffer(cmd);
713 	if (!cmd_sense_buf) {
714 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
715 		return;
716 	}
717 
718 	cmd->se_cmd_flags |= SCF_TRANSPORT_TASK_SENSE;
719 	memcpy(cmd_sense_buf, sense, cmd->scsi_sense_length);
720 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
721 }
722 EXPORT_SYMBOL(transport_copy_sense_to_cmd);
723 
724 void target_complete_cmd(struct se_cmd *cmd, u8 scsi_status)
725 {
726 	struct se_device *dev = cmd->se_dev;
727 	int success;
728 	unsigned long flags;
729 
730 	cmd->scsi_status = scsi_status;
731 
732 	spin_lock_irqsave(&cmd->t_state_lock, flags);
733 	switch (cmd->scsi_status) {
734 	case SAM_STAT_CHECK_CONDITION:
735 		if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE)
736 			success = 1;
737 		else
738 			success = 0;
739 		break;
740 	default:
741 		success = 1;
742 		break;
743 	}
744 
745 	/*
746 	 * Check for case where an explicit ABORT_TASK has been received
747 	 * and transport_wait_for_tasks() will be waiting for completion..
748 	 */
749 	if (cmd->transport_state & CMD_T_ABORTED ||
750 	    cmd->transport_state & CMD_T_STOP) {
751 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
752 		/*
753 		 * If COMPARE_AND_WRITE was stopped by __transport_wait_for_tasks(),
754 		 * release se_device->caw_sem obtained by sbc_compare_and_write()
755 		 * since target_complete_ok_work() or target_complete_failure_work()
756 		 * won't be called to invoke the normal CAW completion callbacks.
757 		 */
758 		if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) {
759 			up(&dev->caw_sem);
760 		}
761 		complete_all(&cmd->t_transport_stop_comp);
762 		return;
763 	} else if (!success) {
764 		INIT_WORK(&cmd->work, target_complete_failure_work);
765 	} else {
766 		INIT_WORK(&cmd->work, target_complete_ok_work);
767 	}
768 
769 	cmd->t_state = TRANSPORT_COMPLETE;
770 	cmd->transport_state |= (CMD_T_COMPLETE | CMD_T_ACTIVE);
771 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
772 
773 	if (cmd->se_cmd_flags & SCF_USE_CPUID)
774 		queue_work_on(cmd->cpuid, target_completion_wq, &cmd->work);
775 	else
776 		queue_work(target_completion_wq, &cmd->work);
777 }
778 EXPORT_SYMBOL(target_complete_cmd);
779 
780 void target_complete_cmd_with_length(struct se_cmd *cmd, u8 scsi_status, int length)
781 {
782 	if (scsi_status == SAM_STAT_GOOD && length < cmd->data_length) {
783 		if (cmd->se_cmd_flags & SCF_UNDERFLOW_BIT) {
784 			cmd->residual_count += cmd->data_length - length;
785 		} else {
786 			cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
787 			cmd->residual_count = cmd->data_length - length;
788 		}
789 
790 		cmd->data_length = length;
791 	}
792 
793 	target_complete_cmd(cmd, scsi_status);
794 }
795 EXPORT_SYMBOL(target_complete_cmd_with_length);
796 
797 static void target_add_to_state_list(struct se_cmd *cmd)
798 {
799 	struct se_device *dev = cmd->se_dev;
800 	unsigned long flags;
801 
802 	spin_lock_irqsave(&dev->execute_task_lock, flags);
803 	if (!cmd->state_active) {
804 		list_add_tail(&cmd->state_list, &dev->state_list);
805 		cmd->state_active = true;
806 	}
807 	spin_unlock_irqrestore(&dev->execute_task_lock, flags);
808 }
809 
810 /*
811  * Handle QUEUE_FULL / -EAGAIN and -ENOMEM status
812  */
813 static void transport_write_pending_qf(struct se_cmd *cmd);
814 static void transport_complete_qf(struct se_cmd *cmd);
815 
816 void target_qf_do_work(struct work_struct *work)
817 {
818 	struct se_device *dev = container_of(work, struct se_device,
819 					qf_work_queue);
820 	LIST_HEAD(qf_cmd_list);
821 	struct se_cmd *cmd, *cmd_tmp;
822 
823 	spin_lock_irq(&dev->qf_cmd_lock);
824 	list_splice_init(&dev->qf_cmd_list, &qf_cmd_list);
825 	spin_unlock_irq(&dev->qf_cmd_lock);
826 
827 	list_for_each_entry_safe(cmd, cmd_tmp, &qf_cmd_list, se_qf_node) {
828 		list_del(&cmd->se_qf_node);
829 		atomic_dec_mb(&dev->dev_qf_count);
830 
831 		pr_debug("Processing %s cmd: %p QUEUE_FULL in work queue"
832 			" context: %s\n", cmd->se_tfo->get_fabric_name(), cmd,
833 			(cmd->t_state == TRANSPORT_COMPLETE_QF_OK) ? "COMPLETE_OK" :
834 			(cmd->t_state == TRANSPORT_COMPLETE_QF_WP) ? "WRITE_PENDING"
835 			: "UNKNOWN");
836 
837 		if (cmd->t_state == TRANSPORT_COMPLETE_QF_WP)
838 			transport_write_pending_qf(cmd);
839 		else if (cmd->t_state == TRANSPORT_COMPLETE_QF_OK ||
840 			 cmd->t_state == TRANSPORT_COMPLETE_QF_ERR)
841 			transport_complete_qf(cmd);
842 	}
843 }
844 
845 unsigned char *transport_dump_cmd_direction(struct se_cmd *cmd)
846 {
847 	switch (cmd->data_direction) {
848 	case DMA_NONE:
849 		return "NONE";
850 	case DMA_FROM_DEVICE:
851 		return "READ";
852 	case DMA_TO_DEVICE:
853 		return "WRITE";
854 	case DMA_BIDIRECTIONAL:
855 		return "BIDI";
856 	default:
857 		break;
858 	}
859 
860 	return "UNKNOWN";
861 }
862 
863 void transport_dump_dev_state(
864 	struct se_device *dev,
865 	char *b,
866 	int *bl)
867 {
868 	*bl += sprintf(b + *bl, "Status: ");
869 	if (dev->export_count)
870 		*bl += sprintf(b + *bl, "ACTIVATED");
871 	else
872 		*bl += sprintf(b + *bl, "DEACTIVATED");
873 
874 	*bl += sprintf(b + *bl, "  Max Queue Depth: %d", dev->queue_depth);
875 	*bl += sprintf(b + *bl, "  SectorSize: %u  HwMaxSectors: %u\n",
876 		dev->dev_attrib.block_size,
877 		dev->dev_attrib.hw_max_sectors);
878 	*bl += sprintf(b + *bl, "        ");
879 }
880 
881 void transport_dump_vpd_proto_id(
882 	struct t10_vpd *vpd,
883 	unsigned char *p_buf,
884 	int p_buf_len)
885 {
886 	unsigned char buf[VPD_TMP_BUF_SIZE];
887 	int len;
888 
889 	memset(buf, 0, VPD_TMP_BUF_SIZE);
890 	len = sprintf(buf, "T10 VPD Protocol Identifier: ");
891 
892 	switch (vpd->protocol_identifier) {
893 	case 0x00:
894 		sprintf(buf+len, "Fibre Channel\n");
895 		break;
896 	case 0x10:
897 		sprintf(buf+len, "Parallel SCSI\n");
898 		break;
899 	case 0x20:
900 		sprintf(buf+len, "SSA\n");
901 		break;
902 	case 0x30:
903 		sprintf(buf+len, "IEEE 1394\n");
904 		break;
905 	case 0x40:
906 		sprintf(buf+len, "SCSI Remote Direct Memory Access"
907 				" Protocol\n");
908 		break;
909 	case 0x50:
910 		sprintf(buf+len, "Internet SCSI (iSCSI)\n");
911 		break;
912 	case 0x60:
913 		sprintf(buf+len, "SAS Serial SCSI Protocol\n");
914 		break;
915 	case 0x70:
916 		sprintf(buf+len, "Automation/Drive Interface Transport"
917 				" Protocol\n");
918 		break;
919 	case 0x80:
920 		sprintf(buf+len, "AT Attachment Interface ATA/ATAPI\n");
921 		break;
922 	default:
923 		sprintf(buf+len, "Unknown 0x%02x\n",
924 				vpd->protocol_identifier);
925 		break;
926 	}
927 
928 	if (p_buf)
929 		strncpy(p_buf, buf, p_buf_len);
930 	else
931 		pr_debug("%s", buf);
932 }
933 
934 void
935 transport_set_vpd_proto_id(struct t10_vpd *vpd, unsigned char *page_83)
936 {
937 	/*
938 	 * Check if the Protocol Identifier Valid (PIV) bit is set..
939 	 *
940 	 * from spc3r23.pdf section 7.5.1
941 	 */
942 	 if (page_83[1] & 0x80) {
943 		vpd->protocol_identifier = (page_83[0] & 0xf0);
944 		vpd->protocol_identifier_set = 1;
945 		transport_dump_vpd_proto_id(vpd, NULL, 0);
946 	}
947 }
948 EXPORT_SYMBOL(transport_set_vpd_proto_id);
949 
950 int transport_dump_vpd_assoc(
951 	struct t10_vpd *vpd,
952 	unsigned char *p_buf,
953 	int p_buf_len)
954 {
955 	unsigned char buf[VPD_TMP_BUF_SIZE];
956 	int ret = 0;
957 	int len;
958 
959 	memset(buf, 0, VPD_TMP_BUF_SIZE);
960 	len = sprintf(buf, "T10 VPD Identifier Association: ");
961 
962 	switch (vpd->association) {
963 	case 0x00:
964 		sprintf(buf+len, "addressed logical unit\n");
965 		break;
966 	case 0x10:
967 		sprintf(buf+len, "target port\n");
968 		break;
969 	case 0x20:
970 		sprintf(buf+len, "SCSI target device\n");
971 		break;
972 	default:
973 		sprintf(buf+len, "Unknown 0x%02x\n", vpd->association);
974 		ret = -EINVAL;
975 		break;
976 	}
977 
978 	if (p_buf)
979 		strncpy(p_buf, buf, p_buf_len);
980 	else
981 		pr_debug("%s", buf);
982 
983 	return ret;
984 }
985 
986 int transport_set_vpd_assoc(struct t10_vpd *vpd, unsigned char *page_83)
987 {
988 	/*
989 	 * The VPD identification association..
990 	 *
991 	 * from spc3r23.pdf Section 7.6.3.1 Table 297
992 	 */
993 	vpd->association = (page_83[1] & 0x30);
994 	return transport_dump_vpd_assoc(vpd, NULL, 0);
995 }
996 EXPORT_SYMBOL(transport_set_vpd_assoc);
997 
998 int transport_dump_vpd_ident_type(
999 	struct t10_vpd *vpd,
1000 	unsigned char *p_buf,
1001 	int p_buf_len)
1002 {
1003 	unsigned char buf[VPD_TMP_BUF_SIZE];
1004 	int ret = 0;
1005 	int len;
1006 
1007 	memset(buf, 0, VPD_TMP_BUF_SIZE);
1008 	len = sprintf(buf, "T10 VPD Identifier Type: ");
1009 
1010 	switch (vpd->device_identifier_type) {
1011 	case 0x00:
1012 		sprintf(buf+len, "Vendor specific\n");
1013 		break;
1014 	case 0x01:
1015 		sprintf(buf+len, "T10 Vendor ID based\n");
1016 		break;
1017 	case 0x02:
1018 		sprintf(buf+len, "EUI-64 based\n");
1019 		break;
1020 	case 0x03:
1021 		sprintf(buf+len, "NAA\n");
1022 		break;
1023 	case 0x04:
1024 		sprintf(buf+len, "Relative target port identifier\n");
1025 		break;
1026 	case 0x08:
1027 		sprintf(buf+len, "SCSI name string\n");
1028 		break;
1029 	default:
1030 		sprintf(buf+len, "Unsupported: 0x%02x\n",
1031 				vpd->device_identifier_type);
1032 		ret = -EINVAL;
1033 		break;
1034 	}
1035 
1036 	if (p_buf) {
1037 		if (p_buf_len < strlen(buf)+1)
1038 			return -EINVAL;
1039 		strncpy(p_buf, buf, p_buf_len);
1040 	} else {
1041 		pr_debug("%s", buf);
1042 	}
1043 
1044 	return ret;
1045 }
1046 
1047 int transport_set_vpd_ident_type(struct t10_vpd *vpd, unsigned char *page_83)
1048 {
1049 	/*
1050 	 * The VPD identifier type..
1051 	 *
1052 	 * from spc3r23.pdf Section 7.6.3.1 Table 298
1053 	 */
1054 	vpd->device_identifier_type = (page_83[1] & 0x0f);
1055 	return transport_dump_vpd_ident_type(vpd, NULL, 0);
1056 }
1057 EXPORT_SYMBOL(transport_set_vpd_ident_type);
1058 
1059 int transport_dump_vpd_ident(
1060 	struct t10_vpd *vpd,
1061 	unsigned char *p_buf,
1062 	int p_buf_len)
1063 {
1064 	unsigned char buf[VPD_TMP_BUF_SIZE];
1065 	int ret = 0;
1066 
1067 	memset(buf, 0, VPD_TMP_BUF_SIZE);
1068 
1069 	switch (vpd->device_identifier_code_set) {
1070 	case 0x01: /* Binary */
1071 		snprintf(buf, sizeof(buf),
1072 			"T10 VPD Binary Device Identifier: %s\n",
1073 			&vpd->device_identifier[0]);
1074 		break;
1075 	case 0x02: /* ASCII */
1076 		snprintf(buf, sizeof(buf),
1077 			"T10 VPD ASCII Device Identifier: %s\n",
1078 			&vpd->device_identifier[0]);
1079 		break;
1080 	case 0x03: /* UTF-8 */
1081 		snprintf(buf, sizeof(buf),
1082 			"T10 VPD UTF-8 Device Identifier: %s\n",
1083 			&vpd->device_identifier[0]);
1084 		break;
1085 	default:
1086 		sprintf(buf, "T10 VPD Device Identifier encoding unsupported:"
1087 			" 0x%02x", vpd->device_identifier_code_set);
1088 		ret = -EINVAL;
1089 		break;
1090 	}
1091 
1092 	if (p_buf)
1093 		strncpy(p_buf, buf, p_buf_len);
1094 	else
1095 		pr_debug("%s", buf);
1096 
1097 	return ret;
1098 }
1099 
1100 int
1101 transport_set_vpd_ident(struct t10_vpd *vpd, unsigned char *page_83)
1102 {
1103 	static const char hex_str[] = "0123456789abcdef";
1104 	int j = 0, i = 4; /* offset to start of the identifier */
1105 
1106 	/*
1107 	 * The VPD Code Set (encoding)
1108 	 *
1109 	 * from spc3r23.pdf Section 7.6.3.1 Table 296
1110 	 */
1111 	vpd->device_identifier_code_set = (page_83[0] & 0x0f);
1112 	switch (vpd->device_identifier_code_set) {
1113 	case 0x01: /* Binary */
1114 		vpd->device_identifier[j++] =
1115 				hex_str[vpd->device_identifier_type];
1116 		while (i < (4 + page_83[3])) {
1117 			vpd->device_identifier[j++] =
1118 				hex_str[(page_83[i] & 0xf0) >> 4];
1119 			vpd->device_identifier[j++] =
1120 				hex_str[page_83[i] & 0x0f];
1121 			i++;
1122 		}
1123 		break;
1124 	case 0x02: /* ASCII */
1125 	case 0x03: /* UTF-8 */
1126 		while (i < (4 + page_83[3]))
1127 			vpd->device_identifier[j++] = page_83[i++];
1128 		break;
1129 	default:
1130 		break;
1131 	}
1132 
1133 	return transport_dump_vpd_ident(vpd, NULL, 0);
1134 }
1135 EXPORT_SYMBOL(transport_set_vpd_ident);
1136 
1137 static sense_reason_t
1138 target_check_max_data_sg_nents(struct se_cmd *cmd, struct se_device *dev,
1139 			       unsigned int size)
1140 {
1141 	u32 mtl;
1142 
1143 	if (!cmd->se_tfo->max_data_sg_nents)
1144 		return TCM_NO_SENSE;
1145 	/*
1146 	 * Check if fabric enforced maximum SGL entries per I/O descriptor
1147 	 * exceeds se_cmd->data_length.  If true, set SCF_UNDERFLOW_BIT +
1148 	 * residual_count and reduce original cmd->data_length to maximum
1149 	 * length based on single PAGE_SIZE entry scatter-lists.
1150 	 */
1151 	mtl = (cmd->se_tfo->max_data_sg_nents * PAGE_SIZE);
1152 	if (cmd->data_length > mtl) {
1153 		/*
1154 		 * If an existing CDB overflow is present, calculate new residual
1155 		 * based on CDB size minus fabric maximum transfer length.
1156 		 *
1157 		 * If an existing CDB underflow is present, calculate new residual
1158 		 * based on original cmd->data_length minus fabric maximum transfer
1159 		 * length.
1160 		 *
1161 		 * Otherwise, set the underflow residual based on cmd->data_length
1162 		 * minus fabric maximum transfer length.
1163 		 */
1164 		if (cmd->se_cmd_flags & SCF_OVERFLOW_BIT) {
1165 			cmd->residual_count = (size - mtl);
1166 		} else if (cmd->se_cmd_flags & SCF_UNDERFLOW_BIT) {
1167 			u32 orig_dl = size + cmd->residual_count;
1168 			cmd->residual_count = (orig_dl - mtl);
1169 		} else {
1170 			cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
1171 			cmd->residual_count = (cmd->data_length - mtl);
1172 		}
1173 		cmd->data_length = mtl;
1174 		/*
1175 		 * Reset sbc_check_prot() calculated protection payload
1176 		 * length based upon the new smaller MTL.
1177 		 */
1178 		if (cmd->prot_length) {
1179 			u32 sectors = (mtl / dev->dev_attrib.block_size);
1180 			cmd->prot_length = dev->prot_length * sectors;
1181 		}
1182 	}
1183 	return TCM_NO_SENSE;
1184 }
1185 
1186 sense_reason_t
1187 target_cmd_size_check(struct se_cmd *cmd, unsigned int size)
1188 {
1189 	struct se_device *dev = cmd->se_dev;
1190 
1191 	if (cmd->unknown_data_length) {
1192 		cmd->data_length = size;
1193 	} else if (size != cmd->data_length) {
1194 		pr_warn_ratelimited("TARGET_CORE[%s]: Expected Transfer Length:"
1195 			" %u does not match SCSI CDB Length: %u for SAM Opcode:"
1196 			" 0x%02x\n", cmd->se_tfo->get_fabric_name(),
1197 				cmd->data_length, size, cmd->t_task_cdb[0]);
1198 
1199 		if (cmd->data_direction == DMA_TO_DEVICE) {
1200 			if (cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) {
1201 				pr_err_ratelimited("Rejecting underflow/overflow"
1202 						   " for WRITE data CDB\n");
1203 				return TCM_INVALID_CDB_FIELD;
1204 			}
1205 			/*
1206 			 * Some fabric drivers like iscsi-target still expect to
1207 			 * always reject overflow writes.  Reject this case until
1208 			 * full fabric driver level support for overflow writes
1209 			 * is introduced tree-wide.
1210 			 */
1211 			if (size > cmd->data_length) {
1212 				pr_err_ratelimited("Rejecting overflow for"
1213 						   " WRITE control CDB\n");
1214 				return TCM_INVALID_CDB_FIELD;
1215 			}
1216 		}
1217 		/*
1218 		 * Reject READ_* or WRITE_* with overflow/underflow for
1219 		 * type SCF_SCSI_DATA_CDB.
1220 		 */
1221 		if (dev->dev_attrib.block_size != 512)  {
1222 			pr_err("Failing OVERFLOW/UNDERFLOW for LBA op"
1223 				" CDB on non 512-byte sector setup subsystem"
1224 				" plugin: %s\n", dev->transport->name);
1225 			/* Returns CHECK_CONDITION + INVALID_CDB_FIELD */
1226 			return TCM_INVALID_CDB_FIELD;
1227 		}
1228 		/*
1229 		 * For the overflow case keep the existing fabric provided
1230 		 * ->data_length.  Otherwise for the underflow case, reset
1231 		 * ->data_length to the smaller SCSI expected data transfer
1232 		 * length.
1233 		 */
1234 		if (size > cmd->data_length) {
1235 			cmd->se_cmd_flags |= SCF_OVERFLOW_BIT;
1236 			cmd->residual_count = (size - cmd->data_length);
1237 		} else {
1238 			cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
1239 			cmd->residual_count = (cmd->data_length - size);
1240 			cmd->data_length = size;
1241 		}
1242 	}
1243 
1244 	return target_check_max_data_sg_nents(cmd, dev, size);
1245 
1246 }
1247 
1248 /*
1249  * Used by fabric modules containing a local struct se_cmd within their
1250  * fabric dependent per I/O descriptor.
1251  *
1252  * Preserves the value of @cmd->tag.
1253  */
1254 void transport_init_se_cmd(
1255 	struct se_cmd *cmd,
1256 	const struct target_core_fabric_ops *tfo,
1257 	struct se_session *se_sess,
1258 	u32 data_length,
1259 	int data_direction,
1260 	int task_attr,
1261 	unsigned char *sense_buffer)
1262 {
1263 	INIT_LIST_HEAD(&cmd->se_delayed_node);
1264 	INIT_LIST_HEAD(&cmd->se_qf_node);
1265 	INIT_LIST_HEAD(&cmd->se_cmd_list);
1266 	INIT_LIST_HEAD(&cmd->state_list);
1267 	init_completion(&cmd->t_transport_stop_comp);
1268 	init_completion(&cmd->cmd_wait_comp);
1269 	spin_lock_init(&cmd->t_state_lock);
1270 	INIT_WORK(&cmd->work, NULL);
1271 	kref_init(&cmd->cmd_kref);
1272 
1273 	cmd->se_tfo = tfo;
1274 	cmd->se_sess = se_sess;
1275 	cmd->data_length = data_length;
1276 	cmd->data_direction = data_direction;
1277 	cmd->sam_task_attr = task_attr;
1278 	cmd->sense_buffer = sense_buffer;
1279 
1280 	cmd->state_active = false;
1281 }
1282 EXPORT_SYMBOL(transport_init_se_cmd);
1283 
1284 static sense_reason_t
1285 transport_check_alloc_task_attr(struct se_cmd *cmd)
1286 {
1287 	struct se_device *dev = cmd->se_dev;
1288 
1289 	/*
1290 	 * Check if SAM Task Attribute emulation is enabled for this
1291 	 * struct se_device storage object
1292 	 */
1293 	if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
1294 		return 0;
1295 
1296 	if (cmd->sam_task_attr == TCM_ACA_TAG) {
1297 		pr_debug("SAM Task Attribute ACA"
1298 			" emulation is not supported\n");
1299 		return TCM_INVALID_CDB_FIELD;
1300 	}
1301 
1302 	return 0;
1303 }
1304 
1305 sense_reason_t
1306 target_setup_cmd_from_cdb(struct se_cmd *cmd, unsigned char *cdb)
1307 {
1308 	struct se_device *dev = cmd->se_dev;
1309 	sense_reason_t ret;
1310 
1311 	/*
1312 	 * Ensure that the received CDB is less than the max (252 + 8) bytes
1313 	 * for VARIABLE_LENGTH_CMD
1314 	 */
1315 	if (scsi_command_size(cdb) > SCSI_MAX_VARLEN_CDB_SIZE) {
1316 		pr_err("Received SCSI CDB with command_size: %d that"
1317 			" exceeds SCSI_MAX_VARLEN_CDB_SIZE: %d\n",
1318 			scsi_command_size(cdb), SCSI_MAX_VARLEN_CDB_SIZE);
1319 		return TCM_INVALID_CDB_FIELD;
1320 	}
1321 	/*
1322 	 * If the received CDB is larger than TCM_MAX_COMMAND_SIZE,
1323 	 * allocate the additional extended CDB buffer now..  Otherwise
1324 	 * setup the pointer from __t_task_cdb to t_task_cdb.
1325 	 */
1326 	if (scsi_command_size(cdb) > sizeof(cmd->__t_task_cdb)) {
1327 		cmd->t_task_cdb = kzalloc(scsi_command_size(cdb),
1328 						GFP_KERNEL);
1329 		if (!cmd->t_task_cdb) {
1330 			pr_err("Unable to allocate cmd->t_task_cdb"
1331 				" %u > sizeof(cmd->__t_task_cdb): %lu ops\n",
1332 				scsi_command_size(cdb),
1333 				(unsigned long)sizeof(cmd->__t_task_cdb));
1334 			return TCM_OUT_OF_RESOURCES;
1335 		}
1336 	} else
1337 		cmd->t_task_cdb = &cmd->__t_task_cdb[0];
1338 	/*
1339 	 * Copy the original CDB into cmd->
1340 	 */
1341 	memcpy(cmd->t_task_cdb, cdb, scsi_command_size(cdb));
1342 
1343 	trace_target_sequencer_start(cmd);
1344 
1345 	ret = dev->transport->parse_cdb(cmd);
1346 	if (ret == TCM_UNSUPPORTED_SCSI_OPCODE)
1347 		pr_warn_ratelimited("%s/%s: Unsupported SCSI Opcode 0x%02x, sending CHECK_CONDITION.\n",
1348 				    cmd->se_tfo->get_fabric_name(),
1349 				    cmd->se_sess->se_node_acl->initiatorname,
1350 				    cmd->t_task_cdb[0]);
1351 	if (ret)
1352 		return ret;
1353 
1354 	ret = transport_check_alloc_task_attr(cmd);
1355 	if (ret)
1356 		return ret;
1357 
1358 	cmd->se_cmd_flags |= SCF_SUPPORTED_SAM_OPCODE;
1359 	atomic_long_inc(&cmd->se_lun->lun_stats.cmd_pdus);
1360 	return 0;
1361 }
1362 EXPORT_SYMBOL(target_setup_cmd_from_cdb);
1363 
1364 /*
1365  * Used by fabric module frontends to queue tasks directly.
1366  * May only be used from process context.
1367  */
1368 int transport_handle_cdb_direct(
1369 	struct se_cmd *cmd)
1370 {
1371 	sense_reason_t ret;
1372 
1373 	if (!cmd->se_lun) {
1374 		dump_stack();
1375 		pr_err("cmd->se_lun is NULL\n");
1376 		return -EINVAL;
1377 	}
1378 	if (in_interrupt()) {
1379 		dump_stack();
1380 		pr_err("transport_generic_handle_cdb cannot be called"
1381 				" from interrupt context\n");
1382 		return -EINVAL;
1383 	}
1384 	/*
1385 	 * Set TRANSPORT_NEW_CMD state and CMD_T_ACTIVE to ensure that
1386 	 * outstanding descriptors are handled correctly during shutdown via
1387 	 * transport_wait_for_tasks()
1388 	 *
1389 	 * Also, we don't take cmd->t_state_lock here as we only expect
1390 	 * this to be called for initial descriptor submission.
1391 	 */
1392 	cmd->t_state = TRANSPORT_NEW_CMD;
1393 	cmd->transport_state |= CMD_T_ACTIVE;
1394 
1395 	/*
1396 	 * transport_generic_new_cmd() is already handling QUEUE_FULL,
1397 	 * so follow TRANSPORT_NEW_CMD processing thread context usage
1398 	 * and call transport_generic_request_failure() if necessary..
1399 	 */
1400 	ret = transport_generic_new_cmd(cmd);
1401 	if (ret)
1402 		transport_generic_request_failure(cmd, ret);
1403 	return 0;
1404 }
1405 EXPORT_SYMBOL(transport_handle_cdb_direct);
1406 
1407 sense_reason_t
1408 transport_generic_map_mem_to_cmd(struct se_cmd *cmd, struct scatterlist *sgl,
1409 		u32 sgl_count, struct scatterlist *sgl_bidi, u32 sgl_bidi_count)
1410 {
1411 	if (!sgl || !sgl_count)
1412 		return 0;
1413 
1414 	/*
1415 	 * Reject SCSI data overflow with map_mem_to_cmd() as incoming
1416 	 * scatterlists already have been set to follow what the fabric
1417 	 * passes for the original expected data transfer length.
1418 	 */
1419 	if (cmd->se_cmd_flags & SCF_OVERFLOW_BIT) {
1420 		pr_warn("Rejecting SCSI DATA overflow for fabric using"
1421 			" SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC\n");
1422 		return TCM_INVALID_CDB_FIELD;
1423 	}
1424 
1425 	cmd->t_data_sg = sgl;
1426 	cmd->t_data_nents = sgl_count;
1427 	cmd->t_bidi_data_sg = sgl_bidi;
1428 	cmd->t_bidi_data_nents = sgl_bidi_count;
1429 
1430 	cmd->se_cmd_flags |= SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC;
1431 	return 0;
1432 }
1433 
1434 /*
1435  * target_submit_cmd_map_sgls - lookup unpacked lun and submit uninitialized
1436  * 			 se_cmd + use pre-allocated SGL memory.
1437  *
1438  * @se_cmd: command descriptor to submit
1439  * @se_sess: associated se_sess for endpoint
1440  * @cdb: pointer to SCSI CDB
1441  * @sense: pointer to SCSI sense buffer
1442  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1443  * @data_length: fabric expected data transfer length
1444  * @task_addr: SAM task attribute
1445  * @data_dir: DMA data direction
1446  * @flags: flags for command submission from target_sc_flags_tables
1447  * @sgl: struct scatterlist memory for unidirectional mapping
1448  * @sgl_count: scatterlist count for unidirectional mapping
1449  * @sgl_bidi: struct scatterlist memory for bidirectional READ mapping
1450  * @sgl_bidi_count: scatterlist count for bidirectional READ mapping
1451  * @sgl_prot: struct scatterlist memory protection information
1452  * @sgl_prot_count: scatterlist count for protection information
1453  *
1454  * Task tags are supported if the caller has set @se_cmd->tag.
1455  *
1456  * Returns non zero to signal active I/O shutdown failure.  All other
1457  * setup exceptions will be returned as a SCSI CHECK_CONDITION response,
1458  * but still return zero here.
1459  *
1460  * This may only be called from process context, and also currently
1461  * assumes internal allocation of fabric payload buffer by target-core.
1462  */
1463 int target_submit_cmd_map_sgls(struct se_cmd *se_cmd, struct se_session *se_sess,
1464 		unsigned char *cdb, unsigned char *sense, u64 unpacked_lun,
1465 		u32 data_length, int task_attr, int data_dir, int flags,
1466 		struct scatterlist *sgl, u32 sgl_count,
1467 		struct scatterlist *sgl_bidi, u32 sgl_bidi_count,
1468 		struct scatterlist *sgl_prot, u32 sgl_prot_count)
1469 {
1470 	struct se_portal_group *se_tpg;
1471 	sense_reason_t rc;
1472 	int ret;
1473 
1474 	se_tpg = se_sess->se_tpg;
1475 	BUG_ON(!se_tpg);
1476 	BUG_ON(se_cmd->se_tfo || se_cmd->se_sess);
1477 	BUG_ON(in_interrupt());
1478 	/*
1479 	 * Initialize se_cmd for target operation.  From this point
1480 	 * exceptions are handled by sending exception status via
1481 	 * target_core_fabric_ops->queue_status() callback
1482 	 */
1483 	transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess,
1484 				data_length, data_dir, task_attr, sense);
1485 
1486 	if (flags & TARGET_SCF_USE_CPUID)
1487 		se_cmd->se_cmd_flags |= SCF_USE_CPUID;
1488 	else
1489 		se_cmd->cpuid = WORK_CPU_UNBOUND;
1490 
1491 	if (flags & TARGET_SCF_UNKNOWN_SIZE)
1492 		se_cmd->unknown_data_length = 1;
1493 	/*
1494 	 * Obtain struct se_cmd->cmd_kref reference and add new cmd to
1495 	 * se_sess->sess_cmd_list.  A second kref_get here is necessary
1496 	 * for fabrics using TARGET_SCF_ACK_KREF that expect a second
1497 	 * kref_put() to happen during fabric packet acknowledgement.
1498 	 */
1499 	ret = target_get_sess_cmd(se_cmd, flags & TARGET_SCF_ACK_KREF);
1500 	if (ret)
1501 		return ret;
1502 	/*
1503 	 * Signal bidirectional data payloads to target-core
1504 	 */
1505 	if (flags & TARGET_SCF_BIDI_OP)
1506 		se_cmd->se_cmd_flags |= SCF_BIDI;
1507 	/*
1508 	 * Locate se_lun pointer and attach it to struct se_cmd
1509 	 */
1510 	rc = transport_lookup_cmd_lun(se_cmd, unpacked_lun);
1511 	if (rc) {
1512 		transport_send_check_condition_and_sense(se_cmd, rc, 0);
1513 		target_put_sess_cmd(se_cmd);
1514 		return 0;
1515 	}
1516 
1517 	rc = target_setup_cmd_from_cdb(se_cmd, cdb);
1518 	if (rc != 0) {
1519 		transport_generic_request_failure(se_cmd, rc);
1520 		return 0;
1521 	}
1522 
1523 	/*
1524 	 * Save pointers for SGLs containing protection information,
1525 	 * if present.
1526 	 */
1527 	if (sgl_prot_count) {
1528 		se_cmd->t_prot_sg = sgl_prot;
1529 		se_cmd->t_prot_nents = sgl_prot_count;
1530 		se_cmd->se_cmd_flags |= SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC;
1531 	}
1532 
1533 	/*
1534 	 * When a non zero sgl_count has been passed perform SGL passthrough
1535 	 * mapping for pre-allocated fabric memory instead of having target
1536 	 * core perform an internal SGL allocation..
1537 	 */
1538 	if (sgl_count != 0) {
1539 		BUG_ON(!sgl);
1540 
1541 		/*
1542 		 * A work-around for tcm_loop as some userspace code via
1543 		 * scsi-generic do not memset their associated read buffers,
1544 		 * so go ahead and do that here for type non-data CDBs.  Also
1545 		 * note that this is currently guaranteed to be a single SGL
1546 		 * for this case by target core in target_setup_cmd_from_cdb()
1547 		 * -> transport_generic_cmd_sequencer().
1548 		 */
1549 		if (!(se_cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) &&
1550 		     se_cmd->data_direction == DMA_FROM_DEVICE) {
1551 			unsigned char *buf = NULL;
1552 
1553 			if (sgl)
1554 				buf = kmap(sg_page(sgl)) + sgl->offset;
1555 
1556 			if (buf) {
1557 				memset(buf, 0, sgl->length);
1558 				kunmap(sg_page(sgl));
1559 			}
1560 		}
1561 
1562 		rc = transport_generic_map_mem_to_cmd(se_cmd, sgl, sgl_count,
1563 				sgl_bidi, sgl_bidi_count);
1564 		if (rc != 0) {
1565 			transport_generic_request_failure(se_cmd, rc);
1566 			return 0;
1567 		}
1568 	}
1569 
1570 	/*
1571 	 * Check if we need to delay processing because of ALUA
1572 	 * Active/NonOptimized primary access state..
1573 	 */
1574 	core_alua_check_nonop_delay(se_cmd);
1575 
1576 	transport_handle_cdb_direct(se_cmd);
1577 	return 0;
1578 }
1579 EXPORT_SYMBOL(target_submit_cmd_map_sgls);
1580 
1581 /*
1582  * target_submit_cmd - lookup unpacked lun and submit uninitialized se_cmd
1583  *
1584  * @se_cmd: command descriptor to submit
1585  * @se_sess: associated se_sess for endpoint
1586  * @cdb: pointer to SCSI CDB
1587  * @sense: pointer to SCSI sense buffer
1588  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1589  * @data_length: fabric expected data transfer length
1590  * @task_addr: SAM task attribute
1591  * @data_dir: DMA data direction
1592  * @flags: flags for command submission from target_sc_flags_tables
1593  *
1594  * Task tags are supported if the caller has set @se_cmd->tag.
1595  *
1596  * Returns non zero to signal active I/O shutdown failure.  All other
1597  * setup exceptions will be returned as a SCSI CHECK_CONDITION response,
1598  * but still return zero here.
1599  *
1600  * This may only be called from process context, and also currently
1601  * assumes internal allocation of fabric payload buffer by target-core.
1602  *
1603  * It also assumes interal target core SGL memory allocation.
1604  */
1605 int target_submit_cmd(struct se_cmd *se_cmd, struct se_session *se_sess,
1606 		unsigned char *cdb, unsigned char *sense, u64 unpacked_lun,
1607 		u32 data_length, int task_attr, int data_dir, int flags)
1608 {
1609 	return target_submit_cmd_map_sgls(se_cmd, se_sess, cdb, sense,
1610 			unpacked_lun, data_length, task_attr, data_dir,
1611 			flags, NULL, 0, NULL, 0, NULL, 0);
1612 }
1613 EXPORT_SYMBOL(target_submit_cmd);
1614 
1615 static void target_complete_tmr_failure(struct work_struct *work)
1616 {
1617 	struct se_cmd *se_cmd = container_of(work, struct se_cmd, work);
1618 
1619 	se_cmd->se_tmr_req->response = TMR_LUN_DOES_NOT_EXIST;
1620 	se_cmd->se_tfo->queue_tm_rsp(se_cmd);
1621 
1622 	transport_lun_remove_cmd(se_cmd);
1623 	transport_cmd_check_stop_to_fabric(se_cmd);
1624 }
1625 
1626 static bool target_lookup_lun_from_tag(struct se_session *se_sess, u64 tag,
1627 				       u64 *unpacked_lun)
1628 {
1629 	struct se_cmd *se_cmd;
1630 	unsigned long flags;
1631 	bool ret = false;
1632 
1633 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
1634 	list_for_each_entry(se_cmd, &se_sess->sess_cmd_list, se_cmd_list) {
1635 		if (se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
1636 			continue;
1637 
1638 		if (se_cmd->tag == tag) {
1639 			*unpacked_lun = se_cmd->orig_fe_lun;
1640 			ret = true;
1641 			break;
1642 		}
1643 	}
1644 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
1645 
1646 	return ret;
1647 }
1648 
1649 /**
1650  * target_submit_tmr - lookup unpacked lun and submit uninitialized se_cmd
1651  *                     for TMR CDBs
1652  *
1653  * @se_cmd: command descriptor to submit
1654  * @se_sess: associated se_sess for endpoint
1655  * @sense: pointer to SCSI sense buffer
1656  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1657  * @fabric_context: fabric context for TMR req
1658  * @tm_type: Type of TM request
1659  * @gfp: gfp type for caller
1660  * @tag: referenced task tag for TMR_ABORT_TASK
1661  * @flags: submit cmd flags
1662  *
1663  * Callable from all contexts.
1664  **/
1665 
1666 int target_submit_tmr(struct se_cmd *se_cmd, struct se_session *se_sess,
1667 		unsigned char *sense, u64 unpacked_lun,
1668 		void *fabric_tmr_ptr, unsigned char tm_type,
1669 		gfp_t gfp, u64 tag, int flags)
1670 {
1671 	struct se_portal_group *se_tpg;
1672 	int ret;
1673 
1674 	se_tpg = se_sess->se_tpg;
1675 	BUG_ON(!se_tpg);
1676 
1677 	transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess,
1678 			      0, DMA_NONE, TCM_SIMPLE_TAG, sense);
1679 	/*
1680 	 * FIXME: Currently expect caller to handle se_cmd->se_tmr_req
1681 	 * allocation failure.
1682 	 */
1683 	ret = core_tmr_alloc_req(se_cmd, fabric_tmr_ptr, tm_type, gfp);
1684 	if (ret < 0)
1685 		return -ENOMEM;
1686 
1687 	if (tm_type == TMR_ABORT_TASK)
1688 		se_cmd->se_tmr_req->ref_task_tag = tag;
1689 
1690 	/* See target_submit_cmd for commentary */
1691 	ret = target_get_sess_cmd(se_cmd, flags & TARGET_SCF_ACK_KREF);
1692 	if (ret) {
1693 		core_tmr_release_req(se_cmd->se_tmr_req);
1694 		return ret;
1695 	}
1696 	/*
1697 	 * If this is ABORT_TASK with no explicit fabric provided LUN,
1698 	 * go ahead and search active session tags for a match to figure
1699 	 * out unpacked_lun for the original se_cmd.
1700 	 */
1701 	if (tm_type == TMR_ABORT_TASK && (flags & TARGET_SCF_LOOKUP_LUN_FROM_TAG)) {
1702 		if (!target_lookup_lun_from_tag(se_sess, tag, &unpacked_lun))
1703 			goto failure;
1704 	}
1705 
1706 	ret = transport_lookup_tmr_lun(se_cmd, unpacked_lun);
1707 	if (ret)
1708 		goto failure;
1709 
1710 	transport_generic_handle_tmr(se_cmd);
1711 	return 0;
1712 
1713 	/*
1714 	 * For callback during failure handling, push this work off
1715 	 * to process context with TMR_LUN_DOES_NOT_EXIST status.
1716 	 */
1717 failure:
1718 	INIT_WORK(&se_cmd->work, target_complete_tmr_failure);
1719 	schedule_work(&se_cmd->work);
1720 	return 0;
1721 }
1722 EXPORT_SYMBOL(target_submit_tmr);
1723 
1724 /*
1725  * Handle SAM-esque emulation for generic transport request failures.
1726  */
1727 void transport_generic_request_failure(struct se_cmd *cmd,
1728 		sense_reason_t sense_reason)
1729 {
1730 	int ret = 0, post_ret = 0;
1731 
1732 	pr_debug("-----[ Storage Engine Exception; sense_reason %d\n",
1733 		 sense_reason);
1734 	target_show_cmd("-----[ ", cmd);
1735 
1736 	/*
1737 	 * For SAM Task Attribute emulation for failed struct se_cmd
1738 	 */
1739 	transport_complete_task_attr(cmd);
1740 
1741 	/*
1742 	 * Handle special case for COMPARE_AND_WRITE failure, where the
1743 	 * callback is expected to drop the per device ->caw_sem.
1744 	 */
1745 	if ((cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) &&
1746 	     cmd->transport_complete_callback)
1747 		cmd->transport_complete_callback(cmd, false, &post_ret);
1748 
1749 	if (transport_check_aborted_status(cmd, 1))
1750 		return;
1751 
1752 	switch (sense_reason) {
1753 	case TCM_NON_EXISTENT_LUN:
1754 	case TCM_UNSUPPORTED_SCSI_OPCODE:
1755 	case TCM_INVALID_CDB_FIELD:
1756 	case TCM_INVALID_PARAMETER_LIST:
1757 	case TCM_PARAMETER_LIST_LENGTH_ERROR:
1758 	case TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE:
1759 	case TCM_UNKNOWN_MODE_PAGE:
1760 	case TCM_WRITE_PROTECTED:
1761 	case TCM_ADDRESS_OUT_OF_RANGE:
1762 	case TCM_CHECK_CONDITION_ABORT_CMD:
1763 	case TCM_CHECK_CONDITION_UNIT_ATTENTION:
1764 	case TCM_CHECK_CONDITION_NOT_READY:
1765 	case TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED:
1766 	case TCM_LOGICAL_BLOCK_APP_TAG_CHECK_FAILED:
1767 	case TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED:
1768 	case TCM_COPY_TARGET_DEVICE_NOT_REACHABLE:
1769 	case TCM_TOO_MANY_TARGET_DESCS:
1770 	case TCM_UNSUPPORTED_TARGET_DESC_TYPE_CODE:
1771 	case TCM_TOO_MANY_SEGMENT_DESCS:
1772 	case TCM_UNSUPPORTED_SEGMENT_DESC_TYPE_CODE:
1773 		break;
1774 	case TCM_OUT_OF_RESOURCES:
1775 		cmd->scsi_status = SAM_STAT_TASK_SET_FULL;
1776 		goto queue_status;
1777 	case TCM_RESERVATION_CONFLICT:
1778 		/*
1779 		 * No SENSE Data payload for this case, set SCSI Status
1780 		 * and queue the response to $FABRIC_MOD.
1781 		 *
1782 		 * Uses linux/include/scsi/scsi.h SAM status codes defs
1783 		 */
1784 		cmd->scsi_status = SAM_STAT_RESERVATION_CONFLICT;
1785 		/*
1786 		 * For UA Interlock Code 11b, a RESERVATION CONFLICT will
1787 		 * establish a UNIT ATTENTION with PREVIOUS RESERVATION
1788 		 * CONFLICT STATUS.
1789 		 *
1790 		 * See spc4r17, section 7.4.6 Control Mode Page, Table 349
1791 		 */
1792 		if (cmd->se_sess &&
1793 		    cmd->se_dev->dev_attrib.emulate_ua_intlck_ctrl == 2) {
1794 			target_ua_allocate_lun(cmd->se_sess->se_node_acl,
1795 					       cmd->orig_fe_lun, 0x2C,
1796 					ASCQ_2CH_PREVIOUS_RESERVATION_CONFLICT_STATUS);
1797 		}
1798 
1799 		goto queue_status;
1800 	default:
1801 		pr_err("Unknown transport error for CDB 0x%02x: %d\n",
1802 			cmd->t_task_cdb[0], sense_reason);
1803 		sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
1804 		break;
1805 	}
1806 
1807 	ret = transport_send_check_condition_and_sense(cmd, sense_reason, 0);
1808 	if (ret)
1809 		goto queue_full;
1810 
1811 check_stop:
1812 	transport_lun_remove_cmd(cmd);
1813 	transport_cmd_check_stop_to_fabric(cmd);
1814 	return;
1815 
1816 queue_status:
1817 	trace_target_cmd_complete(cmd);
1818 	ret = cmd->se_tfo->queue_status(cmd);
1819 	if (!ret)
1820 		goto check_stop;
1821 queue_full:
1822 	transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
1823 }
1824 EXPORT_SYMBOL(transport_generic_request_failure);
1825 
1826 void __target_execute_cmd(struct se_cmd *cmd, bool do_checks)
1827 {
1828 	sense_reason_t ret;
1829 
1830 	if (!cmd->execute_cmd) {
1831 		ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
1832 		goto err;
1833 	}
1834 	if (do_checks) {
1835 		/*
1836 		 * Check for an existing UNIT ATTENTION condition after
1837 		 * target_handle_task_attr() has done SAM task attr
1838 		 * checking, and possibly have already defered execution
1839 		 * out to target_restart_delayed_cmds() context.
1840 		 */
1841 		ret = target_scsi3_ua_check(cmd);
1842 		if (ret)
1843 			goto err;
1844 
1845 		ret = target_alua_state_check(cmd);
1846 		if (ret)
1847 			goto err;
1848 
1849 		ret = target_check_reservation(cmd);
1850 		if (ret) {
1851 			cmd->scsi_status = SAM_STAT_RESERVATION_CONFLICT;
1852 			goto err;
1853 		}
1854 	}
1855 
1856 	ret = cmd->execute_cmd(cmd);
1857 	if (!ret)
1858 		return;
1859 err:
1860 	spin_lock_irq(&cmd->t_state_lock);
1861 	cmd->transport_state &= ~CMD_T_SENT;
1862 	spin_unlock_irq(&cmd->t_state_lock);
1863 
1864 	transport_generic_request_failure(cmd, ret);
1865 }
1866 
1867 static int target_write_prot_action(struct se_cmd *cmd)
1868 {
1869 	u32 sectors;
1870 	/*
1871 	 * Perform WRITE_INSERT of PI using software emulation when backend
1872 	 * device has PI enabled, if the transport has not already generated
1873 	 * PI using hardware WRITE_INSERT offload.
1874 	 */
1875 	switch (cmd->prot_op) {
1876 	case TARGET_PROT_DOUT_INSERT:
1877 		if (!(cmd->se_sess->sup_prot_ops & TARGET_PROT_DOUT_INSERT))
1878 			sbc_dif_generate(cmd);
1879 		break;
1880 	case TARGET_PROT_DOUT_STRIP:
1881 		if (cmd->se_sess->sup_prot_ops & TARGET_PROT_DOUT_STRIP)
1882 			break;
1883 
1884 		sectors = cmd->data_length >> ilog2(cmd->se_dev->dev_attrib.block_size);
1885 		cmd->pi_err = sbc_dif_verify(cmd, cmd->t_task_lba,
1886 					     sectors, 0, cmd->t_prot_sg, 0);
1887 		if (unlikely(cmd->pi_err)) {
1888 			spin_lock_irq(&cmd->t_state_lock);
1889 			cmd->transport_state &= ~CMD_T_SENT;
1890 			spin_unlock_irq(&cmd->t_state_lock);
1891 			transport_generic_request_failure(cmd, cmd->pi_err);
1892 			return -1;
1893 		}
1894 		break;
1895 	default:
1896 		break;
1897 	}
1898 
1899 	return 0;
1900 }
1901 
1902 static bool target_handle_task_attr(struct se_cmd *cmd)
1903 {
1904 	struct se_device *dev = cmd->se_dev;
1905 
1906 	if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
1907 		return false;
1908 
1909 	cmd->se_cmd_flags |= SCF_TASK_ATTR_SET;
1910 
1911 	/*
1912 	 * Check for the existence of HEAD_OF_QUEUE, and if true return 1
1913 	 * to allow the passed struct se_cmd list of tasks to the front of the list.
1914 	 */
1915 	switch (cmd->sam_task_attr) {
1916 	case TCM_HEAD_TAG:
1917 		pr_debug("Added HEAD_OF_QUEUE for CDB: 0x%02x\n",
1918 			 cmd->t_task_cdb[0]);
1919 		return false;
1920 	case TCM_ORDERED_TAG:
1921 		atomic_inc_mb(&dev->dev_ordered_sync);
1922 
1923 		pr_debug("Added ORDERED for CDB: 0x%02x to ordered list\n",
1924 			 cmd->t_task_cdb[0]);
1925 
1926 		/*
1927 		 * Execute an ORDERED command if no other older commands
1928 		 * exist that need to be completed first.
1929 		 */
1930 		if (!atomic_read(&dev->simple_cmds))
1931 			return false;
1932 		break;
1933 	default:
1934 		/*
1935 		 * For SIMPLE and UNTAGGED Task Attribute commands
1936 		 */
1937 		atomic_inc_mb(&dev->simple_cmds);
1938 		break;
1939 	}
1940 
1941 	if (atomic_read(&dev->dev_ordered_sync) == 0)
1942 		return false;
1943 
1944 	spin_lock(&dev->delayed_cmd_lock);
1945 	list_add_tail(&cmd->se_delayed_node, &dev->delayed_cmd_list);
1946 	spin_unlock(&dev->delayed_cmd_lock);
1947 
1948 	pr_debug("Added CDB: 0x%02x Task Attr: 0x%02x to delayed CMD listn",
1949 		cmd->t_task_cdb[0], cmd->sam_task_attr);
1950 	return true;
1951 }
1952 
1953 static int __transport_check_aborted_status(struct se_cmd *, int);
1954 
1955 void target_execute_cmd(struct se_cmd *cmd)
1956 {
1957 	/*
1958 	 * Determine if frontend context caller is requesting the stopping of
1959 	 * this command for frontend exceptions.
1960 	 *
1961 	 * If the received CDB has aleady been aborted stop processing it here.
1962 	 */
1963 	spin_lock_irq(&cmd->t_state_lock);
1964 	if (__transport_check_aborted_status(cmd, 1)) {
1965 		spin_unlock_irq(&cmd->t_state_lock);
1966 		return;
1967 	}
1968 	if (cmd->transport_state & CMD_T_STOP) {
1969 		pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08llx\n",
1970 			__func__, __LINE__, cmd->tag);
1971 
1972 		spin_unlock_irq(&cmd->t_state_lock);
1973 		complete_all(&cmd->t_transport_stop_comp);
1974 		return;
1975 	}
1976 
1977 	cmd->t_state = TRANSPORT_PROCESSING;
1978 	cmd->transport_state &= ~CMD_T_PRE_EXECUTE;
1979 	cmd->transport_state |= CMD_T_ACTIVE | CMD_T_SENT;
1980 	spin_unlock_irq(&cmd->t_state_lock);
1981 
1982 	if (target_write_prot_action(cmd))
1983 		return;
1984 
1985 	if (target_handle_task_attr(cmd)) {
1986 		spin_lock_irq(&cmd->t_state_lock);
1987 		cmd->transport_state &= ~CMD_T_SENT;
1988 		spin_unlock_irq(&cmd->t_state_lock);
1989 		return;
1990 	}
1991 
1992 	__target_execute_cmd(cmd, true);
1993 }
1994 EXPORT_SYMBOL(target_execute_cmd);
1995 
1996 /*
1997  * Process all commands up to the last received ORDERED task attribute which
1998  * requires another blocking boundary
1999  */
2000 static void target_restart_delayed_cmds(struct se_device *dev)
2001 {
2002 	for (;;) {
2003 		struct se_cmd *cmd;
2004 
2005 		spin_lock(&dev->delayed_cmd_lock);
2006 		if (list_empty(&dev->delayed_cmd_list)) {
2007 			spin_unlock(&dev->delayed_cmd_lock);
2008 			break;
2009 		}
2010 
2011 		cmd = list_entry(dev->delayed_cmd_list.next,
2012 				 struct se_cmd, se_delayed_node);
2013 		list_del(&cmd->se_delayed_node);
2014 		spin_unlock(&dev->delayed_cmd_lock);
2015 
2016 		cmd->transport_state |= CMD_T_SENT;
2017 
2018 		__target_execute_cmd(cmd, true);
2019 
2020 		if (cmd->sam_task_attr == TCM_ORDERED_TAG)
2021 			break;
2022 	}
2023 }
2024 
2025 /*
2026  * Called from I/O completion to determine which dormant/delayed
2027  * and ordered cmds need to have their tasks added to the execution queue.
2028  */
2029 static void transport_complete_task_attr(struct se_cmd *cmd)
2030 {
2031 	struct se_device *dev = cmd->se_dev;
2032 
2033 	if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
2034 		return;
2035 
2036 	if (!(cmd->se_cmd_flags & SCF_TASK_ATTR_SET))
2037 		goto restart;
2038 
2039 	if (cmd->sam_task_attr == TCM_SIMPLE_TAG) {
2040 		atomic_dec_mb(&dev->simple_cmds);
2041 		dev->dev_cur_ordered_id++;
2042 	} else if (cmd->sam_task_attr == TCM_HEAD_TAG) {
2043 		dev->dev_cur_ordered_id++;
2044 		pr_debug("Incremented dev_cur_ordered_id: %u for HEAD_OF_QUEUE\n",
2045 			 dev->dev_cur_ordered_id);
2046 	} else if (cmd->sam_task_attr == TCM_ORDERED_TAG) {
2047 		atomic_dec_mb(&dev->dev_ordered_sync);
2048 
2049 		dev->dev_cur_ordered_id++;
2050 		pr_debug("Incremented dev_cur_ordered_id: %u for ORDERED\n",
2051 			 dev->dev_cur_ordered_id);
2052 	}
2053 	cmd->se_cmd_flags &= ~SCF_TASK_ATTR_SET;
2054 
2055 restart:
2056 	target_restart_delayed_cmds(dev);
2057 }
2058 
2059 static void transport_complete_qf(struct se_cmd *cmd)
2060 {
2061 	int ret = 0;
2062 
2063 	transport_complete_task_attr(cmd);
2064 	/*
2065 	 * If a fabric driver ->write_pending() or ->queue_data_in() callback
2066 	 * has returned neither -ENOMEM or -EAGAIN, assume it's fatal and
2067 	 * the same callbacks should not be retried.  Return CHECK_CONDITION
2068 	 * if a scsi_status is not already set.
2069 	 *
2070 	 * If a fabric driver ->queue_status() has returned non zero, always
2071 	 * keep retrying no matter what..
2072 	 */
2073 	if (cmd->t_state == TRANSPORT_COMPLETE_QF_ERR) {
2074 		if (cmd->scsi_status)
2075 			goto queue_status;
2076 
2077 		cmd->se_cmd_flags |= SCF_EMULATED_TASK_SENSE;
2078 		cmd->scsi_status = SAM_STAT_CHECK_CONDITION;
2079 		cmd->scsi_sense_length  = TRANSPORT_SENSE_BUFFER;
2080 		translate_sense_reason(cmd, TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE);
2081 		goto queue_status;
2082 	}
2083 
2084 	if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE)
2085 		goto queue_status;
2086 
2087 	switch (cmd->data_direction) {
2088 	case DMA_FROM_DEVICE:
2089 		if (cmd->scsi_status)
2090 			goto queue_status;
2091 
2092 		trace_target_cmd_complete(cmd);
2093 		ret = cmd->se_tfo->queue_data_in(cmd);
2094 		break;
2095 	case DMA_TO_DEVICE:
2096 		if (cmd->se_cmd_flags & SCF_BIDI) {
2097 			ret = cmd->se_tfo->queue_data_in(cmd);
2098 			break;
2099 		}
2100 		/* fall through */
2101 	case DMA_NONE:
2102 queue_status:
2103 		trace_target_cmd_complete(cmd);
2104 		ret = cmd->se_tfo->queue_status(cmd);
2105 		break;
2106 	default:
2107 		break;
2108 	}
2109 
2110 	if (ret < 0) {
2111 		transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
2112 		return;
2113 	}
2114 	transport_lun_remove_cmd(cmd);
2115 	transport_cmd_check_stop_to_fabric(cmd);
2116 }
2117 
2118 static void transport_handle_queue_full(struct se_cmd *cmd, struct se_device *dev,
2119 					int err, bool write_pending)
2120 {
2121 	/*
2122 	 * -EAGAIN or -ENOMEM signals retry of ->write_pending() and/or
2123 	 * ->queue_data_in() callbacks from new process context.
2124 	 *
2125 	 * Otherwise for other errors, transport_complete_qf() will send
2126 	 * CHECK_CONDITION via ->queue_status() instead of attempting to
2127 	 * retry associated fabric driver data-transfer callbacks.
2128 	 */
2129 	if (err == -EAGAIN || err == -ENOMEM) {
2130 		cmd->t_state = (write_pending) ? TRANSPORT_COMPLETE_QF_WP :
2131 						 TRANSPORT_COMPLETE_QF_OK;
2132 	} else {
2133 		pr_warn_ratelimited("Got unknown fabric queue status: %d\n", err);
2134 		cmd->t_state = TRANSPORT_COMPLETE_QF_ERR;
2135 	}
2136 
2137 	spin_lock_irq(&dev->qf_cmd_lock);
2138 	list_add_tail(&cmd->se_qf_node, &cmd->se_dev->qf_cmd_list);
2139 	atomic_inc_mb(&dev->dev_qf_count);
2140 	spin_unlock_irq(&cmd->se_dev->qf_cmd_lock);
2141 
2142 	schedule_work(&cmd->se_dev->qf_work_queue);
2143 }
2144 
2145 static bool target_read_prot_action(struct se_cmd *cmd)
2146 {
2147 	switch (cmd->prot_op) {
2148 	case TARGET_PROT_DIN_STRIP:
2149 		if (!(cmd->se_sess->sup_prot_ops & TARGET_PROT_DIN_STRIP)) {
2150 			u32 sectors = cmd->data_length >>
2151 				  ilog2(cmd->se_dev->dev_attrib.block_size);
2152 
2153 			cmd->pi_err = sbc_dif_verify(cmd, cmd->t_task_lba,
2154 						     sectors, 0, cmd->t_prot_sg,
2155 						     0);
2156 			if (cmd->pi_err)
2157 				return true;
2158 		}
2159 		break;
2160 	case TARGET_PROT_DIN_INSERT:
2161 		if (cmd->se_sess->sup_prot_ops & TARGET_PROT_DIN_INSERT)
2162 			break;
2163 
2164 		sbc_dif_generate(cmd);
2165 		break;
2166 	default:
2167 		break;
2168 	}
2169 
2170 	return false;
2171 }
2172 
2173 static void target_complete_ok_work(struct work_struct *work)
2174 {
2175 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
2176 	int ret;
2177 
2178 	/*
2179 	 * Check if we need to move delayed/dormant tasks from cmds on the
2180 	 * delayed execution list after a HEAD_OF_QUEUE or ORDERED Task
2181 	 * Attribute.
2182 	 */
2183 	transport_complete_task_attr(cmd);
2184 
2185 	/*
2186 	 * Check to schedule QUEUE_FULL work, or execute an existing
2187 	 * cmd->transport_qf_callback()
2188 	 */
2189 	if (atomic_read(&cmd->se_dev->dev_qf_count) != 0)
2190 		schedule_work(&cmd->se_dev->qf_work_queue);
2191 
2192 	/*
2193 	 * Check if we need to send a sense buffer from
2194 	 * the struct se_cmd in question.
2195 	 */
2196 	if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) {
2197 		WARN_ON(!cmd->scsi_status);
2198 		ret = transport_send_check_condition_and_sense(
2199 					cmd, 0, 1);
2200 		if (ret)
2201 			goto queue_full;
2202 
2203 		transport_lun_remove_cmd(cmd);
2204 		transport_cmd_check_stop_to_fabric(cmd);
2205 		return;
2206 	}
2207 	/*
2208 	 * Check for a callback, used by amongst other things
2209 	 * XDWRITE_READ_10 and COMPARE_AND_WRITE emulation.
2210 	 */
2211 	if (cmd->transport_complete_callback) {
2212 		sense_reason_t rc;
2213 		bool caw = (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE);
2214 		bool zero_dl = !(cmd->data_length);
2215 		int post_ret = 0;
2216 
2217 		rc = cmd->transport_complete_callback(cmd, true, &post_ret);
2218 		if (!rc && !post_ret) {
2219 			if (caw && zero_dl)
2220 				goto queue_rsp;
2221 
2222 			return;
2223 		} else if (rc) {
2224 			ret = transport_send_check_condition_and_sense(cmd,
2225 						rc, 0);
2226 			if (ret)
2227 				goto queue_full;
2228 
2229 			transport_lun_remove_cmd(cmd);
2230 			transport_cmd_check_stop_to_fabric(cmd);
2231 			return;
2232 		}
2233 	}
2234 
2235 queue_rsp:
2236 	switch (cmd->data_direction) {
2237 	case DMA_FROM_DEVICE:
2238 		if (cmd->scsi_status)
2239 			goto queue_status;
2240 
2241 		atomic_long_add(cmd->data_length,
2242 				&cmd->se_lun->lun_stats.tx_data_octets);
2243 		/*
2244 		 * Perform READ_STRIP of PI using software emulation when
2245 		 * backend had PI enabled, if the transport will not be
2246 		 * performing hardware READ_STRIP offload.
2247 		 */
2248 		if (target_read_prot_action(cmd)) {
2249 			ret = transport_send_check_condition_and_sense(cmd,
2250 						cmd->pi_err, 0);
2251 			if (ret)
2252 				goto queue_full;
2253 
2254 			transport_lun_remove_cmd(cmd);
2255 			transport_cmd_check_stop_to_fabric(cmd);
2256 			return;
2257 		}
2258 
2259 		trace_target_cmd_complete(cmd);
2260 		ret = cmd->se_tfo->queue_data_in(cmd);
2261 		if (ret)
2262 			goto queue_full;
2263 		break;
2264 	case DMA_TO_DEVICE:
2265 		atomic_long_add(cmd->data_length,
2266 				&cmd->se_lun->lun_stats.rx_data_octets);
2267 		/*
2268 		 * Check if we need to send READ payload for BIDI-COMMAND
2269 		 */
2270 		if (cmd->se_cmd_flags & SCF_BIDI) {
2271 			atomic_long_add(cmd->data_length,
2272 					&cmd->se_lun->lun_stats.tx_data_octets);
2273 			ret = cmd->se_tfo->queue_data_in(cmd);
2274 			if (ret)
2275 				goto queue_full;
2276 			break;
2277 		}
2278 		/* fall through */
2279 	case DMA_NONE:
2280 queue_status:
2281 		trace_target_cmd_complete(cmd);
2282 		ret = cmd->se_tfo->queue_status(cmd);
2283 		if (ret)
2284 			goto queue_full;
2285 		break;
2286 	default:
2287 		break;
2288 	}
2289 
2290 	transport_lun_remove_cmd(cmd);
2291 	transport_cmd_check_stop_to_fabric(cmd);
2292 	return;
2293 
2294 queue_full:
2295 	pr_debug("Handling complete_ok QUEUE_FULL: se_cmd: %p,"
2296 		" data_direction: %d\n", cmd, cmd->data_direction);
2297 
2298 	transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
2299 }
2300 
2301 void target_free_sgl(struct scatterlist *sgl, int nents)
2302 {
2303 	sgl_free_n_order(sgl, nents, 0);
2304 }
2305 EXPORT_SYMBOL(target_free_sgl);
2306 
2307 static inline void transport_reset_sgl_orig(struct se_cmd *cmd)
2308 {
2309 	/*
2310 	 * Check for saved t_data_sg that may be used for COMPARE_AND_WRITE
2311 	 * emulation, and free + reset pointers if necessary..
2312 	 */
2313 	if (!cmd->t_data_sg_orig)
2314 		return;
2315 
2316 	kfree(cmd->t_data_sg);
2317 	cmd->t_data_sg = cmd->t_data_sg_orig;
2318 	cmd->t_data_sg_orig = NULL;
2319 	cmd->t_data_nents = cmd->t_data_nents_orig;
2320 	cmd->t_data_nents_orig = 0;
2321 }
2322 
2323 static inline void transport_free_pages(struct se_cmd *cmd)
2324 {
2325 	if (!(cmd->se_cmd_flags & SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC)) {
2326 		target_free_sgl(cmd->t_prot_sg, cmd->t_prot_nents);
2327 		cmd->t_prot_sg = NULL;
2328 		cmd->t_prot_nents = 0;
2329 	}
2330 
2331 	if (cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) {
2332 		/*
2333 		 * Release special case READ buffer payload required for
2334 		 * SG_TO_MEM_NOALLOC to function with COMPARE_AND_WRITE
2335 		 */
2336 		if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) {
2337 			target_free_sgl(cmd->t_bidi_data_sg,
2338 					   cmd->t_bidi_data_nents);
2339 			cmd->t_bidi_data_sg = NULL;
2340 			cmd->t_bidi_data_nents = 0;
2341 		}
2342 		transport_reset_sgl_orig(cmd);
2343 		return;
2344 	}
2345 	transport_reset_sgl_orig(cmd);
2346 
2347 	target_free_sgl(cmd->t_data_sg, cmd->t_data_nents);
2348 	cmd->t_data_sg = NULL;
2349 	cmd->t_data_nents = 0;
2350 
2351 	target_free_sgl(cmd->t_bidi_data_sg, cmd->t_bidi_data_nents);
2352 	cmd->t_bidi_data_sg = NULL;
2353 	cmd->t_bidi_data_nents = 0;
2354 }
2355 
2356 void *transport_kmap_data_sg(struct se_cmd *cmd)
2357 {
2358 	struct scatterlist *sg = cmd->t_data_sg;
2359 	struct page **pages;
2360 	int i;
2361 
2362 	/*
2363 	 * We need to take into account a possible offset here for fabrics like
2364 	 * tcm_loop who may be using a contig buffer from the SCSI midlayer for
2365 	 * control CDBs passed as SGLs via transport_generic_map_mem_to_cmd()
2366 	 */
2367 	if (!cmd->t_data_nents)
2368 		return NULL;
2369 
2370 	BUG_ON(!sg);
2371 	if (cmd->t_data_nents == 1)
2372 		return kmap(sg_page(sg)) + sg->offset;
2373 
2374 	/* >1 page. use vmap */
2375 	pages = kmalloc_array(cmd->t_data_nents, sizeof(*pages), GFP_KERNEL);
2376 	if (!pages)
2377 		return NULL;
2378 
2379 	/* convert sg[] to pages[] */
2380 	for_each_sg(cmd->t_data_sg, sg, cmd->t_data_nents, i) {
2381 		pages[i] = sg_page(sg);
2382 	}
2383 
2384 	cmd->t_data_vmap = vmap(pages, cmd->t_data_nents,  VM_MAP, PAGE_KERNEL);
2385 	kfree(pages);
2386 	if (!cmd->t_data_vmap)
2387 		return NULL;
2388 
2389 	return cmd->t_data_vmap + cmd->t_data_sg[0].offset;
2390 }
2391 EXPORT_SYMBOL(transport_kmap_data_sg);
2392 
2393 void transport_kunmap_data_sg(struct se_cmd *cmd)
2394 {
2395 	if (!cmd->t_data_nents) {
2396 		return;
2397 	} else if (cmd->t_data_nents == 1) {
2398 		kunmap(sg_page(cmd->t_data_sg));
2399 		return;
2400 	}
2401 
2402 	vunmap(cmd->t_data_vmap);
2403 	cmd->t_data_vmap = NULL;
2404 }
2405 EXPORT_SYMBOL(transport_kunmap_data_sg);
2406 
2407 int
2408 target_alloc_sgl(struct scatterlist **sgl, unsigned int *nents, u32 length,
2409 		 bool zero_page, bool chainable)
2410 {
2411 	gfp_t gfp = GFP_KERNEL | (zero_page ? __GFP_ZERO : 0);
2412 
2413 	*sgl = sgl_alloc_order(length, 0, chainable, gfp, nents);
2414 	return *sgl ? 0 : -ENOMEM;
2415 }
2416 EXPORT_SYMBOL(target_alloc_sgl);
2417 
2418 /*
2419  * Allocate any required resources to execute the command.  For writes we
2420  * might not have the payload yet, so notify the fabric via a call to
2421  * ->write_pending instead. Otherwise place it on the execution queue.
2422  */
2423 sense_reason_t
2424 transport_generic_new_cmd(struct se_cmd *cmd)
2425 {
2426 	unsigned long flags;
2427 	int ret = 0;
2428 	bool zero_flag = !(cmd->se_cmd_flags & SCF_SCSI_DATA_CDB);
2429 
2430 	if (cmd->prot_op != TARGET_PROT_NORMAL &&
2431 	    !(cmd->se_cmd_flags & SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC)) {
2432 		ret = target_alloc_sgl(&cmd->t_prot_sg, &cmd->t_prot_nents,
2433 				       cmd->prot_length, true, false);
2434 		if (ret < 0)
2435 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2436 	}
2437 
2438 	/*
2439 	 * Determine is the TCM fabric module has already allocated physical
2440 	 * memory, and is directly calling transport_generic_map_mem_to_cmd()
2441 	 * beforehand.
2442 	 */
2443 	if (!(cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) &&
2444 	    cmd->data_length) {
2445 
2446 		if ((cmd->se_cmd_flags & SCF_BIDI) ||
2447 		    (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE)) {
2448 			u32 bidi_length;
2449 
2450 			if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE)
2451 				bidi_length = cmd->t_task_nolb *
2452 					      cmd->se_dev->dev_attrib.block_size;
2453 			else
2454 				bidi_length = cmd->data_length;
2455 
2456 			ret = target_alloc_sgl(&cmd->t_bidi_data_sg,
2457 					       &cmd->t_bidi_data_nents,
2458 					       bidi_length, zero_flag, false);
2459 			if (ret < 0)
2460 				return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2461 		}
2462 
2463 		ret = target_alloc_sgl(&cmd->t_data_sg, &cmd->t_data_nents,
2464 				       cmd->data_length, zero_flag, false);
2465 		if (ret < 0)
2466 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2467 	} else if ((cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) &&
2468 		    cmd->data_length) {
2469 		/*
2470 		 * Special case for COMPARE_AND_WRITE with fabrics
2471 		 * using SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC.
2472 		 */
2473 		u32 caw_length = cmd->t_task_nolb *
2474 				 cmd->se_dev->dev_attrib.block_size;
2475 
2476 		ret = target_alloc_sgl(&cmd->t_bidi_data_sg,
2477 				       &cmd->t_bidi_data_nents,
2478 				       caw_length, zero_flag, false);
2479 		if (ret < 0)
2480 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2481 	}
2482 	/*
2483 	 * If this command is not a write we can execute it right here,
2484 	 * for write buffers we need to notify the fabric driver first
2485 	 * and let it call back once the write buffers are ready.
2486 	 */
2487 	target_add_to_state_list(cmd);
2488 	if (cmd->data_direction != DMA_TO_DEVICE || cmd->data_length == 0) {
2489 		target_execute_cmd(cmd);
2490 		return 0;
2491 	}
2492 
2493 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2494 	cmd->t_state = TRANSPORT_WRITE_PENDING;
2495 	/*
2496 	 * Determine if frontend context caller is requesting the stopping of
2497 	 * this command for frontend exceptions.
2498 	 */
2499 	if (cmd->transport_state & CMD_T_STOP) {
2500 		pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08llx\n",
2501 			 __func__, __LINE__, cmd->tag);
2502 
2503 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2504 
2505 		complete_all(&cmd->t_transport_stop_comp);
2506 		return 0;
2507 	}
2508 	cmd->transport_state &= ~CMD_T_ACTIVE;
2509 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2510 
2511 	ret = cmd->se_tfo->write_pending(cmd);
2512 	if (ret)
2513 		goto queue_full;
2514 
2515 	return 0;
2516 
2517 queue_full:
2518 	pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n", cmd);
2519 	transport_handle_queue_full(cmd, cmd->se_dev, ret, true);
2520 	return 0;
2521 }
2522 EXPORT_SYMBOL(transport_generic_new_cmd);
2523 
2524 static void transport_write_pending_qf(struct se_cmd *cmd)
2525 {
2526 	unsigned long flags;
2527 	int ret;
2528 	bool stop;
2529 
2530 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2531 	stop = (cmd->transport_state & (CMD_T_STOP | CMD_T_ABORTED));
2532 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2533 
2534 	if (stop) {
2535 		pr_debug("%s:%d CMD_T_STOP|CMD_T_ABORTED for ITT: 0x%08llx\n",
2536 			__func__, __LINE__, cmd->tag);
2537 		complete_all(&cmd->t_transport_stop_comp);
2538 		return;
2539 	}
2540 
2541 	ret = cmd->se_tfo->write_pending(cmd);
2542 	if (ret) {
2543 		pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n",
2544 			 cmd);
2545 		transport_handle_queue_full(cmd, cmd->se_dev, ret, true);
2546 	}
2547 }
2548 
2549 static bool
2550 __transport_wait_for_tasks(struct se_cmd *, bool, bool *, bool *,
2551 			   unsigned long *flags);
2552 
2553 static void target_wait_free_cmd(struct se_cmd *cmd, bool *aborted, bool *tas)
2554 {
2555 	unsigned long flags;
2556 
2557 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2558 	__transport_wait_for_tasks(cmd, true, aborted, tas, &flags);
2559 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2560 }
2561 
2562 int transport_generic_free_cmd(struct se_cmd *cmd, int wait_for_tasks)
2563 {
2564 	int ret = 0;
2565 	bool aborted = false, tas = false;
2566 
2567 	if (!(cmd->se_cmd_flags & SCF_SE_LUN_CMD)) {
2568 		if (wait_for_tasks && (cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
2569 			target_wait_free_cmd(cmd, &aborted, &tas);
2570 
2571 		if (!aborted || tas)
2572 			ret = target_put_sess_cmd(cmd);
2573 	} else {
2574 		if (wait_for_tasks)
2575 			target_wait_free_cmd(cmd, &aborted, &tas);
2576 		/*
2577 		 * Handle WRITE failure case where transport_generic_new_cmd()
2578 		 * has already added se_cmd to state_list, but fabric has
2579 		 * failed command before I/O submission.
2580 		 */
2581 		if (cmd->state_active)
2582 			target_remove_from_state_list(cmd);
2583 
2584 		if (cmd->se_lun)
2585 			transport_lun_remove_cmd(cmd);
2586 
2587 		if (!aborted || tas)
2588 			ret = target_put_sess_cmd(cmd);
2589 	}
2590 	/*
2591 	 * If the task has been internally aborted due to TMR ABORT_TASK
2592 	 * or LUN_RESET, target_core_tmr.c is responsible for performing
2593 	 * the remaining calls to target_put_sess_cmd(), and not the
2594 	 * callers of this function.
2595 	 */
2596 	if (aborted) {
2597 		pr_debug("Detected CMD_T_ABORTED for ITT: %llu\n", cmd->tag);
2598 		wait_for_completion(&cmd->cmd_wait_comp);
2599 		cmd->se_tfo->release_cmd(cmd);
2600 		ret = 1;
2601 	}
2602 	return ret;
2603 }
2604 EXPORT_SYMBOL(transport_generic_free_cmd);
2605 
2606 /* target_get_sess_cmd - Add command to active ->sess_cmd_list
2607  * @se_cmd:	command descriptor to add
2608  * @ack_kref:	Signal that fabric will perform an ack target_put_sess_cmd()
2609  */
2610 int target_get_sess_cmd(struct se_cmd *se_cmd, bool ack_kref)
2611 {
2612 	struct se_session *se_sess = se_cmd->se_sess;
2613 	unsigned long flags;
2614 	int ret = 0;
2615 
2616 	/*
2617 	 * Add a second kref if the fabric caller is expecting to handle
2618 	 * fabric acknowledgement that requires two target_put_sess_cmd()
2619 	 * invocations before se_cmd descriptor release.
2620 	 */
2621 	if (ack_kref) {
2622 		if (!kref_get_unless_zero(&se_cmd->cmd_kref))
2623 			return -EINVAL;
2624 
2625 		se_cmd->se_cmd_flags |= SCF_ACK_KREF;
2626 	}
2627 
2628 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2629 	if (se_sess->sess_tearing_down) {
2630 		ret = -ESHUTDOWN;
2631 		goto out;
2632 	}
2633 	se_cmd->transport_state |= CMD_T_PRE_EXECUTE;
2634 	list_add_tail(&se_cmd->se_cmd_list, &se_sess->sess_cmd_list);
2635 out:
2636 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2637 
2638 	if (ret && ack_kref)
2639 		target_put_sess_cmd(se_cmd);
2640 
2641 	return ret;
2642 }
2643 EXPORT_SYMBOL(target_get_sess_cmd);
2644 
2645 static void target_free_cmd_mem(struct se_cmd *cmd)
2646 {
2647 	transport_free_pages(cmd);
2648 
2649 	if (cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
2650 		core_tmr_release_req(cmd->se_tmr_req);
2651 	if (cmd->t_task_cdb != cmd->__t_task_cdb)
2652 		kfree(cmd->t_task_cdb);
2653 }
2654 
2655 static void target_release_cmd_kref(struct kref *kref)
2656 {
2657 	struct se_cmd *se_cmd = container_of(kref, struct se_cmd, cmd_kref);
2658 	struct se_session *se_sess = se_cmd->se_sess;
2659 	unsigned long flags;
2660 	bool fabric_stop;
2661 
2662 	if (se_sess) {
2663 		spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2664 
2665 		spin_lock(&se_cmd->t_state_lock);
2666 		fabric_stop = (se_cmd->transport_state & CMD_T_FABRIC_STOP) &&
2667 			      (se_cmd->transport_state & CMD_T_ABORTED);
2668 		spin_unlock(&se_cmd->t_state_lock);
2669 
2670 		if (se_cmd->cmd_wait_set || fabric_stop) {
2671 			list_del_init(&se_cmd->se_cmd_list);
2672 			spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2673 			target_free_cmd_mem(se_cmd);
2674 			complete(&se_cmd->cmd_wait_comp);
2675 			return;
2676 		}
2677 		list_del_init(&se_cmd->se_cmd_list);
2678 		spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2679 	}
2680 
2681 	target_free_cmd_mem(se_cmd);
2682 	se_cmd->se_tfo->release_cmd(se_cmd);
2683 }
2684 
2685 /**
2686  * target_put_sess_cmd - decrease the command reference count
2687  * @se_cmd:	command to drop a reference from
2688  *
2689  * Returns 1 if and only if this target_put_sess_cmd() call caused the
2690  * refcount to drop to zero. Returns zero otherwise.
2691  */
2692 int target_put_sess_cmd(struct se_cmd *se_cmd)
2693 {
2694 	return kref_put(&se_cmd->cmd_kref, target_release_cmd_kref);
2695 }
2696 EXPORT_SYMBOL(target_put_sess_cmd);
2697 
2698 static const char *data_dir_name(enum dma_data_direction d)
2699 {
2700 	switch (d) {
2701 	case DMA_BIDIRECTIONAL:	return "BIDI";
2702 	case DMA_TO_DEVICE:	return "WRITE";
2703 	case DMA_FROM_DEVICE:	return "READ";
2704 	case DMA_NONE:		return "NONE";
2705 	}
2706 
2707 	return "(?)";
2708 }
2709 
2710 static const char *cmd_state_name(enum transport_state_table t)
2711 {
2712 	switch (t) {
2713 	case TRANSPORT_NO_STATE:	return "NO_STATE";
2714 	case TRANSPORT_NEW_CMD:		return "NEW_CMD";
2715 	case TRANSPORT_WRITE_PENDING:	return "WRITE_PENDING";
2716 	case TRANSPORT_PROCESSING:	return "PROCESSING";
2717 	case TRANSPORT_COMPLETE:	return "COMPLETE";
2718 	case TRANSPORT_ISTATE_PROCESSING:
2719 					return "ISTATE_PROCESSING";
2720 	case TRANSPORT_COMPLETE_QF_WP:	return "COMPLETE_QF_WP";
2721 	case TRANSPORT_COMPLETE_QF_OK:	return "COMPLETE_QF_OK";
2722 	case TRANSPORT_COMPLETE_QF_ERR:	return "COMPLETE_QF_ERR";
2723 	}
2724 
2725 	return "(?)";
2726 }
2727 
2728 static void target_append_str(char **str, const char *txt)
2729 {
2730 	char *prev = *str;
2731 
2732 	*str = *str ? kasprintf(GFP_ATOMIC, "%s,%s", *str, txt) :
2733 		kstrdup(txt, GFP_ATOMIC);
2734 	kfree(prev);
2735 }
2736 
2737 /*
2738  * Convert a transport state bitmask into a string. The caller is
2739  * responsible for freeing the returned pointer.
2740  */
2741 static char *target_ts_to_str(u32 ts)
2742 {
2743 	char *str = NULL;
2744 
2745 	if (ts & CMD_T_ABORTED)
2746 		target_append_str(&str, "aborted");
2747 	if (ts & CMD_T_ACTIVE)
2748 		target_append_str(&str, "active");
2749 	if (ts & CMD_T_COMPLETE)
2750 		target_append_str(&str, "complete");
2751 	if (ts & CMD_T_SENT)
2752 		target_append_str(&str, "sent");
2753 	if (ts & CMD_T_STOP)
2754 		target_append_str(&str, "stop");
2755 	if (ts & CMD_T_FABRIC_STOP)
2756 		target_append_str(&str, "fabric_stop");
2757 
2758 	return str;
2759 }
2760 
2761 static const char *target_tmf_name(enum tcm_tmreq_table tmf)
2762 {
2763 	switch (tmf) {
2764 	case TMR_ABORT_TASK:		return "ABORT_TASK";
2765 	case TMR_ABORT_TASK_SET:	return "ABORT_TASK_SET";
2766 	case TMR_CLEAR_ACA:		return "CLEAR_ACA";
2767 	case TMR_CLEAR_TASK_SET:	return "CLEAR_TASK_SET";
2768 	case TMR_LUN_RESET:		return "LUN_RESET";
2769 	case TMR_TARGET_WARM_RESET:	return "TARGET_WARM_RESET";
2770 	case TMR_TARGET_COLD_RESET:	return "TARGET_COLD_RESET";
2771 	case TMR_UNKNOWN:		break;
2772 	}
2773 	return "(?)";
2774 }
2775 
2776 void target_show_cmd(const char *pfx, struct se_cmd *cmd)
2777 {
2778 	char *ts_str = target_ts_to_str(cmd->transport_state);
2779 	const u8 *cdb = cmd->t_task_cdb;
2780 	struct se_tmr_req *tmf = cmd->se_tmr_req;
2781 
2782 	if (!(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)) {
2783 		pr_debug("%scmd %#02x:%#02x with tag %#llx dir %s i_state %d t_state %s len %d refcnt %d transport_state %s\n",
2784 			 pfx, cdb[0], cdb[1], cmd->tag,
2785 			 data_dir_name(cmd->data_direction),
2786 			 cmd->se_tfo->get_cmd_state(cmd),
2787 			 cmd_state_name(cmd->t_state), cmd->data_length,
2788 			 kref_read(&cmd->cmd_kref), ts_str);
2789 	} else {
2790 		pr_debug("%stmf %s with tag %#llx ref_task_tag %#llx i_state %d t_state %s refcnt %d transport_state %s\n",
2791 			 pfx, target_tmf_name(tmf->function), cmd->tag,
2792 			 tmf->ref_task_tag, cmd->se_tfo->get_cmd_state(cmd),
2793 			 cmd_state_name(cmd->t_state),
2794 			 kref_read(&cmd->cmd_kref), ts_str);
2795 	}
2796 	kfree(ts_str);
2797 }
2798 EXPORT_SYMBOL(target_show_cmd);
2799 
2800 /* target_sess_cmd_list_set_waiting - Flag all commands in
2801  *         sess_cmd_list to complete cmd_wait_comp.  Set
2802  *         sess_tearing_down so no more commands are queued.
2803  * @se_sess:	session to flag
2804  */
2805 void target_sess_cmd_list_set_waiting(struct se_session *se_sess)
2806 {
2807 	struct se_cmd *se_cmd, *tmp_cmd;
2808 	unsigned long flags;
2809 	int rc;
2810 
2811 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2812 	if (se_sess->sess_tearing_down) {
2813 		spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2814 		return;
2815 	}
2816 	se_sess->sess_tearing_down = 1;
2817 	list_splice_init(&se_sess->sess_cmd_list, &se_sess->sess_wait_list);
2818 
2819 	list_for_each_entry_safe(se_cmd, tmp_cmd,
2820 				 &se_sess->sess_wait_list, se_cmd_list) {
2821 		rc = kref_get_unless_zero(&se_cmd->cmd_kref);
2822 		if (rc) {
2823 			se_cmd->cmd_wait_set = 1;
2824 			spin_lock(&se_cmd->t_state_lock);
2825 			se_cmd->transport_state |= CMD_T_FABRIC_STOP;
2826 			spin_unlock(&se_cmd->t_state_lock);
2827 		} else
2828 			list_del_init(&se_cmd->se_cmd_list);
2829 	}
2830 
2831 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2832 }
2833 EXPORT_SYMBOL(target_sess_cmd_list_set_waiting);
2834 
2835 /* target_wait_for_sess_cmds - Wait for outstanding descriptors
2836  * @se_sess:    session to wait for active I/O
2837  */
2838 void target_wait_for_sess_cmds(struct se_session *se_sess)
2839 {
2840 	struct se_cmd *se_cmd, *tmp_cmd;
2841 	unsigned long flags;
2842 	bool tas;
2843 
2844 	list_for_each_entry_safe(se_cmd, tmp_cmd,
2845 				&se_sess->sess_wait_list, se_cmd_list) {
2846 		pr_debug("Waiting for se_cmd: %p t_state: %d, fabric state:"
2847 			" %d\n", se_cmd, se_cmd->t_state,
2848 			se_cmd->se_tfo->get_cmd_state(se_cmd));
2849 
2850 		spin_lock_irqsave(&se_cmd->t_state_lock, flags);
2851 		tas = (se_cmd->transport_state & CMD_T_TAS);
2852 		spin_unlock_irqrestore(&se_cmd->t_state_lock, flags);
2853 
2854 		if (!target_put_sess_cmd(se_cmd)) {
2855 			if (tas)
2856 				target_put_sess_cmd(se_cmd);
2857 		}
2858 
2859 		wait_for_completion(&se_cmd->cmd_wait_comp);
2860 		pr_debug("After cmd_wait_comp: se_cmd: %p t_state: %d"
2861 			" fabric state: %d\n", se_cmd, se_cmd->t_state,
2862 			se_cmd->se_tfo->get_cmd_state(se_cmd));
2863 
2864 		se_cmd->se_tfo->release_cmd(se_cmd);
2865 	}
2866 
2867 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2868 	WARN_ON(!list_empty(&se_sess->sess_cmd_list));
2869 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2870 
2871 }
2872 EXPORT_SYMBOL(target_wait_for_sess_cmds);
2873 
2874 static void target_lun_confirm(struct percpu_ref *ref)
2875 {
2876 	struct se_lun *lun = container_of(ref, struct se_lun, lun_ref);
2877 
2878 	complete(&lun->lun_ref_comp);
2879 }
2880 
2881 void transport_clear_lun_ref(struct se_lun *lun)
2882 {
2883 	/*
2884 	 * Mark the percpu-ref as DEAD, switch to atomic_t mode, drop
2885 	 * the initial reference and schedule confirm kill to be
2886 	 * executed after one full RCU grace period has completed.
2887 	 */
2888 	percpu_ref_kill_and_confirm(&lun->lun_ref, target_lun_confirm);
2889 	/*
2890 	 * The first completion waits for percpu_ref_switch_to_atomic_rcu()
2891 	 * to call target_lun_confirm after lun->lun_ref has been marked
2892 	 * as __PERCPU_REF_DEAD on all CPUs, and switches to atomic_t
2893 	 * mode so that percpu_ref_tryget_live() lookup of lun->lun_ref
2894 	 * fails for all new incoming I/O.
2895 	 */
2896 	wait_for_completion(&lun->lun_ref_comp);
2897 	/*
2898 	 * The second completion waits for percpu_ref_put_many() to
2899 	 * invoke ->release() after lun->lun_ref has switched to
2900 	 * atomic_t mode, and lun->lun_ref.count has reached zero.
2901 	 *
2902 	 * At this point all target-core lun->lun_ref references have
2903 	 * been dropped via transport_lun_remove_cmd(), and it's safe
2904 	 * to proceed with the remaining LUN shutdown.
2905 	 */
2906 	wait_for_completion(&lun->lun_shutdown_comp);
2907 }
2908 
2909 static bool
2910 __transport_wait_for_tasks(struct se_cmd *cmd, bool fabric_stop,
2911 			   bool *aborted, bool *tas, unsigned long *flags)
2912 	__releases(&cmd->t_state_lock)
2913 	__acquires(&cmd->t_state_lock)
2914 {
2915 
2916 	assert_spin_locked(&cmd->t_state_lock);
2917 	WARN_ON_ONCE(!irqs_disabled());
2918 
2919 	if (fabric_stop)
2920 		cmd->transport_state |= CMD_T_FABRIC_STOP;
2921 
2922 	if (cmd->transport_state & CMD_T_ABORTED)
2923 		*aborted = true;
2924 
2925 	if (cmd->transport_state & CMD_T_TAS)
2926 		*tas = true;
2927 
2928 	if (!(cmd->se_cmd_flags & SCF_SE_LUN_CMD) &&
2929 	    !(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
2930 		return false;
2931 
2932 	if (!(cmd->se_cmd_flags & SCF_SUPPORTED_SAM_OPCODE) &&
2933 	    !(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
2934 		return false;
2935 
2936 	if (!(cmd->transport_state & CMD_T_ACTIVE))
2937 		return false;
2938 
2939 	if (fabric_stop && *aborted)
2940 		return false;
2941 
2942 	cmd->transport_state |= CMD_T_STOP;
2943 
2944 	target_show_cmd("wait_for_tasks: Stopping ", cmd);
2945 
2946 	spin_unlock_irqrestore(&cmd->t_state_lock, *flags);
2947 
2948 	while (!wait_for_completion_timeout(&cmd->t_transport_stop_comp,
2949 					    180 * HZ))
2950 		target_show_cmd("wait for tasks: ", cmd);
2951 
2952 	spin_lock_irqsave(&cmd->t_state_lock, *flags);
2953 	cmd->transport_state &= ~(CMD_T_ACTIVE | CMD_T_STOP);
2954 
2955 	pr_debug("wait_for_tasks: Stopped wait_for_completion(&cmd->"
2956 		 "t_transport_stop_comp) for ITT: 0x%08llx\n", cmd->tag);
2957 
2958 	return true;
2959 }
2960 
2961 /**
2962  * transport_wait_for_tasks - set CMD_T_STOP and wait for t_transport_stop_comp
2963  * @cmd: command to wait on
2964  */
2965 bool transport_wait_for_tasks(struct se_cmd *cmd)
2966 {
2967 	unsigned long flags;
2968 	bool ret, aborted = false, tas = false;
2969 
2970 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2971 	ret = __transport_wait_for_tasks(cmd, false, &aborted, &tas, &flags);
2972 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2973 
2974 	return ret;
2975 }
2976 EXPORT_SYMBOL(transport_wait_for_tasks);
2977 
2978 struct sense_info {
2979 	u8 key;
2980 	u8 asc;
2981 	u8 ascq;
2982 	bool add_sector_info;
2983 };
2984 
2985 static const struct sense_info sense_info_table[] = {
2986 	[TCM_NO_SENSE] = {
2987 		.key = NOT_READY
2988 	},
2989 	[TCM_NON_EXISTENT_LUN] = {
2990 		.key = ILLEGAL_REQUEST,
2991 		.asc = 0x25 /* LOGICAL UNIT NOT SUPPORTED */
2992 	},
2993 	[TCM_UNSUPPORTED_SCSI_OPCODE] = {
2994 		.key = ILLEGAL_REQUEST,
2995 		.asc = 0x20, /* INVALID COMMAND OPERATION CODE */
2996 	},
2997 	[TCM_SECTOR_COUNT_TOO_MANY] = {
2998 		.key = ILLEGAL_REQUEST,
2999 		.asc = 0x20, /* INVALID COMMAND OPERATION CODE */
3000 	},
3001 	[TCM_UNKNOWN_MODE_PAGE] = {
3002 		.key = ILLEGAL_REQUEST,
3003 		.asc = 0x24, /* INVALID FIELD IN CDB */
3004 	},
3005 	[TCM_CHECK_CONDITION_ABORT_CMD] = {
3006 		.key = ABORTED_COMMAND,
3007 		.asc = 0x29, /* BUS DEVICE RESET FUNCTION OCCURRED */
3008 		.ascq = 0x03,
3009 	},
3010 	[TCM_INCORRECT_AMOUNT_OF_DATA] = {
3011 		.key = ABORTED_COMMAND,
3012 		.asc = 0x0c, /* WRITE ERROR */
3013 		.ascq = 0x0d, /* NOT ENOUGH UNSOLICITED DATA */
3014 	},
3015 	[TCM_INVALID_CDB_FIELD] = {
3016 		.key = ILLEGAL_REQUEST,
3017 		.asc = 0x24, /* INVALID FIELD IN CDB */
3018 	},
3019 	[TCM_INVALID_PARAMETER_LIST] = {
3020 		.key = ILLEGAL_REQUEST,
3021 		.asc = 0x26, /* INVALID FIELD IN PARAMETER LIST */
3022 	},
3023 	[TCM_TOO_MANY_TARGET_DESCS] = {
3024 		.key = ILLEGAL_REQUEST,
3025 		.asc = 0x26,
3026 		.ascq = 0x06, /* TOO MANY TARGET DESCRIPTORS */
3027 	},
3028 	[TCM_UNSUPPORTED_TARGET_DESC_TYPE_CODE] = {
3029 		.key = ILLEGAL_REQUEST,
3030 		.asc = 0x26,
3031 		.ascq = 0x07, /* UNSUPPORTED TARGET DESCRIPTOR TYPE CODE */
3032 	},
3033 	[TCM_TOO_MANY_SEGMENT_DESCS] = {
3034 		.key = ILLEGAL_REQUEST,
3035 		.asc = 0x26,
3036 		.ascq = 0x08, /* TOO MANY SEGMENT DESCRIPTORS */
3037 	},
3038 	[TCM_UNSUPPORTED_SEGMENT_DESC_TYPE_CODE] = {
3039 		.key = ILLEGAL_REQUEST,
3040 		.asc = 0x26,
3041 		.ascq = 0x09, /* UNSUPPORTED SEGMENT DESCRIPTOR TYPE CODE */
3042 	},
3043 	[TCM_PARAMETER_LIST_LENGTH_ERROR] = {
3044 		.key = ILLEGAL_REQUEST,
3045 		.asc = 0x1a, /* PARAMETER LIST LENGTH ERROR */
3046 	},
3047 	[TCM_UNEXPECTED_UNSOLICITED_DATA] = {
3048 		.key = ILLEGAL_REQUEST,
3049 		.asc = 0x0c, /* WRITE ERROR */
3050 		.ascq = 0x0c, /* UNEXPECTED_UNSOLICITED_DATA */
3051 	},
3052 	[TCM_SERVICE_CRC_ERROR] = {
3053 		.key = ABORTED_COMMAND,
3054 		.asc = 0x47, /* PROTOCOL SERVICE CRC ERROR */
3055 		.ascq = 0x05, /* N/A */
3056 	},
3057 	[TCM_SNACK_REJECTED] = {
3058 		.key = ABORTED_COMMAND,
3059 		.asc = 0x11, /* READ ERROR */
3060 		.ascq = 0x13, /* FAILED RETRANSMISSION REQUEST */
3061 	},
3062 	[TCM_WRITE_PROTECTED] = {
3063 		.key = DATA_PROTECT,
3064 		.asc = 0x27, /* WRITE PROTECTED */
3065 	},
3066 	[TCM_ADDRESS_OUT_OF_RANGE] = {
3067 		.key = ILLEGAL_REQUEST,
3068 		.asc = 0x21, /* LOGICAL BLOCK ADDRESS OUT OF RANGE */
3069 	},
3070 	[TCM_CHECK_CONDITION_UNIT_ATTENTION] = {
3071 		.key = UNIT_ATTENTION,
3072 	},
3073 	[TCM_CHECK_CONDITION_NOT_READY] = {
3074 		.key = NOT_READY,
3075 	},
3076 	[TCM_MISCOMPARE_VERIFY] = {
3077 		.key = MISCOMPARE,
3078 		.asc = 0x1d, /* MISCOMPARE DURING VERIFY OPERATION */
3079 		.ascq = 0x00,
3080 	},
3081 	[TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED] = {
3082 		.key = ABORTED_COMMAND,
3083 		.asc = 0x10,
3084 		.ascq = 0x01, /* LOGICAL BLOCK GUARD CHECK FAILED */
3085 		.add_sector_info = true,
3086 	},
3087 	[TCM_LOGICAL_BLOCK_APP_TAG_CHECK_FAILED] = {
3088 		.key = ABORTED_COMMAND,
3089 		.asc = 0x10,
3090 		.ascq = 0x02, /* LOGICAL BLOCK APPLICATION TAG CHECK FAILED */
3091 		.add_sector_info = true,
3092 	},
3093 	[TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED] = {
3094 		.key = ABORTED_COMMAND,
3095 		.asc = 0x10,
3096 		.ascq = 0x03, /* LOGICAL BLOCK REFERENCE TAG CHECK FAILED */
3097 		.add_sector_info = true,
3098 	},
3099 	[TCM_COPY_TARGET_DEVICE_NOT_REACHABLE] = {
3100 		.key = COPY_ABORTED,
3101 		.asc = 0x0d,
3102 		.ascq = 0x02, /* COPY TARGET DEVICE NOT REACHABLE */
3103 
3104 	},
3105 	[TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE] = {
3106 		/*
3107 		 * Returning ILLEGAL REQUEST would cause immediate IO errors on
3108 		 * Solaris initiators.  Returning NOT READY instead means the
3109 		 * operations will be retried a finite number of times and we
3110 		 * can survive intermittent errors.
3111 		 */
3112 		.key = NOT_READY,
3113 		.asc = 0x08, /* LOGICAL UNIT COMMUNICATION FAILURE */
3114 	},
3115 	[TCM_INSUFFICIENT_REGISTRATION_RESOURCES] = {
3116 		/*
3117 		 * From spc4r22 section5.7.7,5.7.8
3118 		 * If a PERSISTENT RESERVE OUT command with a REGISTER service action
3119 		 * or a REGISTER AND IGNORE EXISTING KEY service action or
3120 		 * REGISTER AND MOVE service actionis attempted,
3121 		 * but there are insufficient device server resources to complete the
3122 		 * operation, then the command shall be terminated with CHECK CONDITION
3123 		 * status, with the sense key set to ILLEGAL REQUEST,and the additonal
3124 		 * sense code set to INSUFFICIENT REGISTRATION RESOURCES.
3125 		 */
3126 		.key = ILLEGAL_REQUEST,
3127 		.asc = 0x55,
3128 		.ascq = 0x04, /* INSUFFICIENT REGISTRATION RESOURCES */
3129 	},
3130 };
3131 
3132 static int translate_sense_reason(struct se_cmd *cmd, sense_reason_t reason)
3133 {
3134 	const struct sense_info *si;
3135 	u8 *buffer = cmd->sense_buffer;
3136 	int r = (__force int)reason;
3137 	u8 asc, ascq;
3138 	bool desc_format = target_sense_desc_format(cmd->se_dev);
3139 
3140 	if (r < ARRAY_SIZE(sense_info_table) && sense_info_table[r].key)
3141 		si = &sense_info_table[r];
3142 	else
3143 		si = &sense_info_table[(__force int)
3144 				       TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE];
3145 
3146 	if (reason == TCM_CHECK_CONDITION_UNIT_ATTENTION) {
3147 		core_scsi3_ua_for_check_condition(cmd, &asc, &ascq);
3148 		WARN_ON_ONCE(asc == 0);
3149 	} else if (si->asc == 0) {
3150 		WARN_ON_ONCE(cmd->scsi_asc == 0);
3151 		asc = cmd->scsi_asc;
3152 		ascq = cmd->scsi_ascq;
3153 	} else {
3154 		asc = si->asc;
3155 		ascq = si->ascq;
3156 	}
3157 
3158 	scsi_build_sense_buffer(desc_format, buffer, si->key, asc, ascq);
3159 	if (si->add_sector_info)
3160 		return scsi_set_sense_information(buffer,
3161 						  cmd->scsi_sense_length,
3162 						  cmd->bad_sector);
3163 
3164 	return 0;
3165 }
3166 
3167 int
3168 transport_send_check_condition_and_sense(struct se_cmd *cmd,
3169 		sense_reason_t reason, int from_transport)
3170 {
3171 	unsigned long flags;
3172 
3173 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3174 	if (cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION) {
3175 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3176 		return 0;
3177 	}
3178 	cmd->se_cmd_flags |= SCF_SENT_CHECK_CONDITION;
3179 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3180 
3181 	if (!from_transport) {
3182 		int rc;
3183 
3184 		cmd->se_cmd_flags |= SCF_EMULATED_TASK_SENSE;
3185 		cmd->scsi_status = SAM_STAT_CHECK_CONDITION;
3186 		cmd->scsi_sense_length  = TRANSPORT_SENSE_BUFFER;
3187 		rc = translate_sense_reason(cmd, reason);
3188 		if (rc)
3189 			return rc;
3190 	}
3191 
3192 	trace_target_cmd_complete(cmd);
3193 	return cmd->se_tfo->queue_status(cmd);
3194 }
3195 EXPORT_SYMBOL(transport_send_check_condition_and_sense);
3196 
3197 static int __transport_check_aborted_status(struct se_cmd *cmd, int send_status)
3198 	__releases(&cmd->t_state_lock)
3199 	__acquires(&cmd->t_state_lock)
3200 {
3201 	int ret;
3202 
3203 	assert_spin_locked(&cmd->t_state_lock);
3204 	WARN_ON_ONCE(!irqs_disabled());
3205 
3206 	if (!(cmd->transport_state & CMD_T_ABORTED))
3207 		return 0;
3208 	/*
3209 	 * If cmd has been aborted but either no status is to be sent or it has
3210 	 * already been sent, just return
3211 	 */
3212 	if (!send_status || !(cmd->se_cmd_flags & SCF_SEND_DELAYED_TAS)) {
3213 		if (send_status)
3214 			cmd->se_cmd_flags |= SCF_SEND_DELAYED_TAS;
3215 		return 1;
3216 	}
3217 
3218 	pr_debug("Sending delayed SAM_STAT_TASK_ABORTED status for CDB:"
3219 		" 0x%02x ITT: 0x%08llx\n", cmd->t_task_cdb[0], cmd->tag);
3220 
3221 	cmd->se_cmd_flags &= ~SCF_SEND_DELAYED_TAS;
3222 	cmd->scsi_status = SAM_STAT_TASK_ABORTED;
3223 	trace_target_cmd_complete(cmd);
3224 
3225 	spin_unlock_irq(&cmd->t_state_lock);
3226 	ret = cmd->se_tfo->queue_status(cmd);
3227 	if (ret)
3228 		transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
3229 	spin_lock_irq(&cmd->t_state_lock);
3230 
3231 	return 1;
3232 }
3233 
3234 int transport_check_aborted_status(struct se_cmd *cmd, int send_status)
3235 {
3236 	int ret;
3237 
3238 	spin_lock_irq(&cmd->t_state_lock);
3239 	ret = __transport_check_aborted_status(cmd, send_status);
3240 	spin_unlock_irq(&cmd->t_state_lock);
3241 
3242 	return ret;
3243 }
3244 EXPORT_SYMBOL(transport_check_aborted_status);
3245 
3246 void transport_send_task_abort(struct se_cmd *cmd)
3247 {
3248 	unsigned long flags;
3249 	int ret;
3250 
3251 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3252 	if (cmd->se_cmd_flags & (SCF_SENT_CHECK_CONDITION)) {
3253 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3254 		return;
3255 	}
3256 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3257 
3258 	/*
3259 	 * If there are still expected incoming fabric WRITEs, we wait
3260 	 * until until they have completed before sending a TASK_ABORTED
3261 	 * response.  This response with TASK_ABORTED status will be
3262 	 * queued back to fabric module by transport_check_aborted_status().
3263 	 */
3264 	if (cmd->data_direction == DMA_TO_DEVICE) {
3265 		if (cmd->se_tfo->write_pending_status(cmd) != 0) {
3266 			spin_lock_irqsave(&cmd->t_state_lock, flags);
3267 			if (cmd->se_cmd_flags & SCF_SEND_DELAYED_TAS) {
3268 				spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3269 				goto send_abort;
3270 			}
3271 			cmd->se_cmd_flags |= SCF_SEND_DELAYED_TAS;
3272 			spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3273 			return;
3274 		}
3275 	}
3276 send_abort:
3277 	cmd->scsi_status = SAM_STAT_TASK_ABORTED;
3278 
3279 	transport_lun_remove_cmd(cmd);
3280 
3281 	pr_debug("Setting SAM_STAT_TASK_ABORTED status for CDB: 0x%02x, ITT: 0x%08llx\n",
3282 		 cmd->t_task_cdb[0], cmd->tag);
3283 
3284 	trace_target_cmd_complete(cmd);
3285 	ret = cmd->se_tfo->queue_status(cmd);
3286 	if (ret)
3287 		transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
3288 }
3289 
3290 static void target_tmr_work(struct work_struct *work)
3291 {
3292 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
3293 	struct se_device *dev = cmd->se_dev;
3294 	struct se_tmr_req *tmr = cmd->se_tmr_req;
3295 	unsigned long flags;
3296 	int ret;
3297 
3298 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3299 	if (cmd->transport_state & CMD_T_ABORTED) {
3300 		tmr->response = TMR_FUNCTION_REJECTED;
3301 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3302 		goto check_stop;
3303 	}
3304 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3305 
3306 	switch (tmr->function) {
3307 	case TMR_ABORT_TASK:
3308 		core_tmr_abort_task(dev, tmr, cmd->se_sess);
3309 		break;
3310 	case TMR_ABORT_TASK_SET:
3311 	case TMR_CLEAR_ACA:
3312 	case TMR_CLEAR_TASK_SET:
3313 		tmr->response = TMR_TASK_MGMT_FUNCTION_NOT_SUPPORTED;
3314 		break;
3315 	case TMR_LUN_RESET:
3316 		ret = core_tmr_lun_reset(dev, tmr, NULL, NULL);
3317 		tmr->response = (!ret) ? TMR_FUNCTION_COMPLETE :
3318 					 TMR_FUNCTION_REJECTED;
3319 		if (tmr->response == TMR_FUNCTION_COMPLETE) {
3320 			target_ua_allocate_lun(cmd->se_sess->se_node_acl,
3321 					       cmd->orig_fe_lun, 0x29,
3322 					       ASCQ_29H_BUS_DEVICE_RESET_FUNCTION_OCCURRED);
3323 		}
3324 		break;
3325 	case TMR_TARGET_WARM_RESET:
3326 		tmr->response = TMR_FUNCTION_REJECTED;
3327 		break;
3328 	case TMR_TARGET_COLD_RESET:
3329 		tmr->response = TMR_FUNCTION_REJECTED;
3330 		break;
3331 	default:
3332 		pr_err("Uknown TMR function: 0x%02x.\n",
3333 				tmr->function);
3334 		tmr->response = TMR_FUNCTION_REJECTED;
3335 		break;
3336 	}
3337 
3338 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3339 	if (cmd->transport_state & CMD_T_ABORTED) {
3340 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3341 		goto check_stop;
3342 	}
3343 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3344 
3345 	cmd->se_tfo->queue_tm_rsp(cmd);
3346 
3347 check_stop:
3348 	transport_lun_remove_cmd(cmd);
3349 	transport_cmd_check_stop_to_fabric(cmd);
3350 }
3351 
3352 int transport_generic_handle_tmr(
3353 	struct se_cmd *cmd)
3354 {
3355 	unsigned long flags;
3356 	bool aborted = false;
3357 
3358 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3359 	if (cmd->transport_state & CMD_T_ABORTED) {
3360 		aborted = true;
3361 	} else {
3362 		cmd->t_state = TRANSPORT_ISTATE_PROCESSING;
3363 		cmd->transport_state |= CMD_T_ACTIVE;
3364 	}
3365 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3366 
3367 	if (aborted) {
3368 		pr_warn_ratelimited("handle_tmr caught CMD_T_ABORTED TMR %d"
3369 			"ref_tag: %llu tag: %llu\n", cmd->se_tmr_req->function,
3370 			cmd->se_tmr_req->ref_task_tag, cmd->tag);
3371 		transport_lun_remove_cmd(cmd);
3372 		transport_cmd_check_stop_to_fabric(cmd);
3373 		return 0;
3374 	}
3375 
3376 	INIT_WORK(&cmd->work, target_tmr_work);
3377 	queue_work(cmd->se_dev->tmr_wq, &cmd->work);
3378 	return 0;
3379 }
3380 EXPORT_SYMBOL(transport_generic_handle_tmr);
3381 
3382 bool
3383 target_check_wce(struct se_device *dev)
3384 {
3385 	bool wce = false;
3386 
3387 	if (dev->transport->get_write_cache)
3388 		wce = dev->transport->get_write_cache(dev);
3389 	else if (dev->dev_attrib.emulate_write_cache > 0)
3390 		wce = true;
3391 
3392 	return wce;
3393 }
3394 
3395 bool
3396 target_check_fua(struct se_device *dev)
3397 {
3398 	return target_check_wce(dev) && dev->dev_attrib.emulate_fua_write > 0;
3399 }
3400