1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*******************************************************************************
3  * Filename:  target_core_transport.c
4  *
5  * This file contains the Generic Target Engine Core.
6  *
7  * (c) Copyright 2002-2013 Datera, Inc.
8  *
9  * Nicholas A. Bellinger <nab@kernel.org>
10  *
11  ******************************************************************************/
12 
13 #include <linux/net.h>
14 #include <linux/delay.h>
15 #include <linux/string.h>
16 #include <linux/timer.h>
17 #include <linux/slab.h>
18 #include <linux/spinlock.h>
19 #include <linux/kthread.h>
20 #include <linux/in.h>
21 #include <linux/cdrom.h>
22 #include <linux/module.h>
23 #include <linux/ratelimit.h>
24 #include <linux/vmalloc.h>
25 #include <asm/unaligned.h>
26 #include <net/sock.h>
27 #include <net/tcp.h>
28 #include <scsi/scsi_proto.h>
29 #include <scsi/scsi_common.h>
30 
31 #include <target/target_core_base.h>
32 #include <target/target_core_backend.h>
33 #include <target/target_core_fabric.h>
34 
35 #include "target_core_internal.h"
36 #include "target_core_alua.h"
37 #include "target_core_pr.h"
38 #include "target_core_ua.h"
39 
40 #define CREATE_TRACE_POINTS
41 #include <trace/events/target.h>
42 
43 static struct workqueue_struct *target_completion_wq;
44 static struct workqueue_struct *target_submission_wq;
45 static struct kmem_cache *se_sess_cache;
46 struct kmem_cache *se_ua_cache;
47 struct kmem_cache *t10_pr_reg_cache;
48 struct kmem_cache *t10_alua_lu_gp_cache;
49 struct kmem_cache *t10_alua_lu_gp_mem_cache;
50 struct kmem_cache *t10_alua_tg_pt_gp_cache;
51 struct kmem_cache *t10_alua_lba_map_cache;
52 struct kmem_cache *t10_alua_lba_map_mem_cache;
53 
54 static void transport_complete_task_attr(struct se_cmd *cmd);
55 static void translate_sense_reason(struct se_cmd *cmd, sense_reason_t reason);
56 static void transport_handle_queue_full(struct se_cmd *cmd,
57 		struct se_device *dev, int err, bool write_pending);
58 static void target_complete_ok_work(struct work_struct *work);
59 
60 int init_se_kmem_caches(void)
61 {
62 	se_sess_cache = kmem_cache_create("se_sess_cache",
63 			sizeof(struct se_session), __alignof__(struct se_session),
64 			0, NULL);
65 	if (!se_sess_cache) {
66 		pr_err("kmem_cache_create() for struct se_session"
67 				" failed\n");
68 		goto out;
69 	}
70 	se_ua_cache = kmem_cache_create("se_ua_cache",
71 			sizeof(struct se_ua), __alignof__(struct se_ua),
72 			0, NULL);
73 	if (!se_ua_cache) {
74 		pr_err("kmem_cache_create() for struct se_ua failed\n");
75 		goto out_free_sess_cache;
76 	}
77 	t10_pr_reg_cache = kmem_cache_create("t10_pr_reg_cache",
78 			sizeof(struct t10_pr_registration),
79 			__alignof__(struct t10_pr_registration), 0, NULL);
80 	if (!t10_pr_reg_cache) {
81 		pr_err("kmem_cache_create() for struct t10_pr_registration"
82 				" failed\n");
83 		goto out_free_ua_cache;
84 	}
85 	t10_alua_lu_gp_cache = kmem_cache_create("t10_alua_lu_gp_cache",
86 			sizeof(struct t10_alua_lu_gp), __alignof__(struct t10_alua_lu_gp),
87 			0, NULL);
88 	if (!t10_alua_lu_gp_cache) {
89 		pr_err("kmem_cache_create() for t10_alua_lu_gp_cache"
90 				" failed\n");
91 		goto out_free_pr_reg_cache;
92 	}
93 	t10_alua_lu_gp_mem_cache = kmem_cache_create("t10_alua_lu_gp_mem_cache",
94 			sizeof(struct t10_alua_lu_gp_member),
95 			__alignof__(struct t10_alua_lu_gp_member), 0, NULL);
96 	if (!t10_alua_lu_gp_mem_cache) {
97 		pr_err("kmem_cache_create() for t10_alua_lu_gp_mem_"
98 				"cache failed\n");
99 		goto out_free_lu_gp_cache;
100 	}
101 	t10_alua_tg_pt_gp_cache = kmem_cache_create("t10_alua_tg_pt_gp_cache",
102 			sizeof(struct t10_alua_tg_pt_gp),
103 			__alignof__(struct t10_alua_tg_pt_gp), 0, NULL);
104 	if (!t10_alua_tg_pt_gp_cache) {
105 		pr_err("kmem_cache_create() for t10_alua_tg_pt_gp_"
106 				"cache failed\n");
107 		goto out_free_lu_gp_mem_cache;
108 	}
109 	t10_alua_lba_map_cache = kmem_cache_create(
110 			"t10_alua_lba_map_cache",
111 			sizeof(struct t10_alua_lba_map),
112 			__alignof__(struct t10_alua_lba_map), 0, NULL);
113 	if (!t10_alua_lba_map_cache) {
114 		pr_err("kmem_cache_create() for t10_alua_lba_map_"
115 				"cache failed\n");
116 		goto out_free_tg_pt_gp_cache;
117 	}
118 	t10_alua_lba_map_mem_cache = kmem_cache_create(
119 			"t10_alua_lba_map_mem_cache",
120 			sizeof(struct t10_alua_lba_map_member),
121 			__alignof__(struct t10_alua_lba_map_member), 0, NULL);
122 	if (!t10_alua_lba_map_mem_cache) {
123 		pr_err("kmem_cache_create() for t10_alua_lba_map_mem_"
124 				"cache failed\n");
125 		goto out_free_lba_map_cache;
126 	}
127 
128 	target_completion_wq = alloc_workqueue("target_completion",
129 					       WQ_MEM_RECLAIM, 0);
130 	if (!target_completion_wq)
131 		goto out_free_lba_map_mem_cache;
132 
133 	target_submission_wq = alloc_workqueue("target_submission",
134 					       WQ_MEM_RECLAIM, 0);
135 	if (!target_submission_wq)
136 		goto out_free_completion_wq;
137 
138 	return 0;
139 
140 out_free_completion_wq:
141 	destroy_workqueue(target_completion_wq);
142 out_free_lba_map_mem_cache:
143 	kmem_cache_destroy(t10_alua_lba_map_mem_cache);
144 out_free_lba_map_cache:
145 	kmem_cache_destroy(t10_alua_lba_map_cache);
146 out_free_tg_pt_gp_cache:
147 	kmem_cache_destroy(t10_alua_tg_pt_gp_cache);
148 out_free_lu_gp_mem_cache:
149 	kmem_cache_destroy(t10_alua_lu_gp_mem_cache);
150 out_free_lu_gp_cache:
151 	kmem_cache_destroy(t10_alua_lu_gp_cache);
152 out_free_pr_reg_cache:
153 	kmem_cache_destroy(t10_pr_reg_cache);
154 out_free_ua_cache:
155 	kmem_cache_destroy(se_ua_cache);
156 out_free_sess_cache:
157 	kmem_cache_destroy(se_sess_cache);
158 out:
159 	return -ENOMEM;
160 }
161 
162 void release_se_kmem_caches(void)
163 {
164 	destroy_workqueue(target_submission_wq);
165 	destroy_workqueue(target_completion_wq);
166 	kmem_cache_destroy(se_sess_cache);
167 	kmem_cache_destroy(se_ua_cache);
168 	kmem_cache_destroy(t10_pr_reg_cache);
169 	kmem_cache_destroy(t10_alua_lu_gp_cache);
170 	kmem_cache_destroy(t10_alua_lu_gp_mem_cache);
171 	kmem_cache_destroy(t10_alua_tg_pt_gp_cache);
172 	kmem_cache_destroy(t10_alua_lba_map_cache);
173 	kmem_cache_destroy(t10_alua_lba_map_mem_cache);
174 }
175 
176 /* This code ensures unique mib indexes are handed out. */
177 static DEFINE_SPINLOCK(scsi_mib_index_lock);
178 static u32 scsi_mib_index[SCSI_INDEX_TYPE_MAX];
179 
180 /*
181  * Allocate a new row index for the entry type specified
182  */
183 u32 scsi_get_new_index(scsi_index_t type)
184 {
185 	u32 new_index;
186 
187 	BUG_ON((type < 0) || (type >= SCSI_INDEX_TYPE_MAX));
188 
189 	spin_lock(&scsi_mib_index_lock);
190 	new_index = ++scsi_mib_index[type];
191 	spin_unlock(&scsi_mib_index_lock);
192 
193 	return new_index;
194 }
195 
196 void transport_subsystem_check_init(void)
197 {
198 	int ret;
199 	static int sub_api_initialized;
200 
201 	if (sub_api_initialized)
202 		return;
203 
204 	ret = IS_ENABLED(CONFIG_TCM_IBLOCK) && request_module("target_core_iblock");
205 	if (ret != 0)
206 		pr_err("Unable to load target_core_iblock\n");
207 
208 	ret = IS_ENABLED(CONFIG_TCM_FILEIO) && request_module("target_core_file");
209 	if (ret != 0)
210 		pr_err("Unable to load target_core_file\n");
211 
212 	ret = IS_ENABLED(CONFIG_TCM_PSCSI) && request_module("target_core_pscsi");
213 	if (ret != 0)
214 		pr_err("Unable to load target_core_pscsi\n");
215 
216 	ret = IS_ENABLED(CONFIG_TCM_USER2) && request_module("target_core_user");
217 	if (ret != 0)
218 		pr_err("Unable to load target_core_user\n");
219 
220 	sub_api_initialized = 1;
221 }
222 
223 static void target_release_cmd_refcnt(struct percpu_ref *ref)
224 {
225 	struct target_cmd_counter *cmd_cnt  = container_of(ref,
226 							   typeof(*cmd_cnt),
227 							   refcnt);
228 	wake_up(&cmd_cnt->refcnt_wq);
229 }
230 
231 struct target_cmd_counter *target_alloc_cmd_counter(void)
232 {
233 	struct target_cmd_counter *cmd_cnt;
234 	int rc;
235 
236 	cmd_cnt = kzalloc(sizeof(*cmd_cnt), GFP_KERNEL);
237 	if (!cmd_cnt)
238 		return NULL;
239 
240 	init_completion(&cmd_cnt->stop_done);
241 	init_waitqueue_head(&cmd_cnt->refcnt_wq);
242 	atomic_set(&cmd_cnt->stopped, 0);
243 
244 	rc = percpu_ref_init(&cmd_cnt->refcnt, target_release_cmd_refcnt, 0,
245 			     GFP_KERNEL);
246 	if (rc)
247 		goto free_cmd_cnt;
248 
249 	return cmd_cnt;
250 
251 free_cmd_cnt:
252 	kfree(cmd_cnt);
253 	return NULL;
254 }
255 EXPORT_SYMBOL_GPL(target_alloc_cmd_counter);
256 
257 void target_free_cmd_counter(struct target_cmd_counter *cmd_cnt)
258 {
259 	/*
260 	 * Drivers like loop do not call target_stop_session during session
261 	 * shutdown so we have to drop the ref taken at init time here.
262 	 */
263 	if (!atomic_read(&cmd_cnt->stopped))
264 		percpu_ref_put(&cmd_cnt->refcnt);
265 
266 	percpu_ref_exit(&cmd_cnt->refcnt);
267 	kfree(cmd_cnt);
268 }
269 EXPORT_SYMBOL_GPL(target_free_cmd_counter);
270 
271 /**
272  * transport_init_session - initialize a session object
273  * @se_sess: Session object pointer.
274  *
275  * The caller must have zero-initialized @se_sess before calling this function.
276  */
277 void transport_init_session(struct se_session *se_sess)
278 {
279 	INIT_LIST_HEAD(&se_sess->sess_list);
280 	INIT_LIST_HEAD(&se_sess->sess_acl_list);
281 	spin_lock_init(&se_sess->sess_cmd_lock);
282 }
283 EXPORT_SYMBOL(transport_init_session);
284 
285 /**
286  * transport_alloc_session - allocate a session object and initialize it
287  * @sup_prot_ops: bitmask that defines which T10-PI modes are supported.
288  */
289 struct se_session *transport_alloc_session(enum target_prot_op sup_prot_ops)
290 {
291 	struct se_session *se_sess;
292 
293 	se_sess = kmem_cache_zalloc(se_sess_cache, GFP_KERNEL);
294 	if (!se_sess) {
295 		pr_err("Unable to allocate struct se_session from"
296 				" se_sess_cache\n");
297 		return ERR_PTR(-ENOMEM);
298 	}
299 	transport_init_session(se_sess);
300 	se_sess->sup_prot_ops = sup_prot_ops;
301 
302 	return se_sess;
303 }
304 EXPORT_SYMBOL(transport_alloc_session);
305 
306 /**
307  * transport_alloc_session_tags - allocate target driver private data
308  * @se_sess:  Session pointer.
309  * @tag_num:  Maximum number of in-flight commands between initiator and target.
310  * @tag_size: Size in bytes of the private data a target driver associates with
311  *	      each command.
312  */
313 int transport_alloc_session_tags(struct se_session *se_sess,
314 			         unsigned int tag_num, unsigned int tag_size)
315 {
316 	int rc;
317 
318 	se_sess->sess_cmd_map = kvcalloc(tag_size, tag_num,
319 					 GFP_KERNEL | __GFP_RETRY_MAYFAIL);
320 	if (!se_sess->sess_cmd_map) {
321 		pr_err("Unable to allocate se_sess->sess_cmd_map\n");
322 		return -ENOMEM;
323 	}
324 
325 	rc = sbitmap_queue_init_node(&se_sess->sess_tag_pool, tag_num, -1,
326 			false, GFP_KERNEL, NUMA_NO_NODE);
327 	if (rc < 0) {
328 		pr_err("Unable to init se_sess->sess_tag_pool,"
329 			" tag_num: %u\n", tag_num);
330 		kvfree(se_sess->sess_cmd_map);
331 		se_sess->sess_cmd_map = NULL;
332 		return -ENOMEM;
333 	}
334 
335 	return 0;
336 }
337 EXPORT_SYMBOL(transport_alloc_session_tags);
338 
339 /**
340  * transport_init_session_tags - allocate a session and target driver private data
341  * @tag_num:  Maximum number of in-flight commands between initiator and target.
342  * @tag_size: Size in bytes of the private data a target driver associates with
343  *	      each command.
344  * @sup_prot_ops: bitmask that defines which T10-PI modes are supported.
345  */
346 static struct se_session *
347 transport_init_session_tags(unsigned int tag_num, unsigned int tag_size,
348 			    enum target_prot_op sup_prot_ops)
349 {
350 	struct se_session *se_sess;
351 	int rc;
352 
353 	if (tag_num != 0 && !tag_size) {
354 		pr_err("init_session_tags called with percpu-ida tag_num:"
355 		       " %u, but zero tag_size\n", tag_num);
356 		return ERR_PTR(-EINVAL);
357 	}
358 	if (!tag_num && tag_size) {
359 		pr_err("init_session_tags called with percpu-ida tag_size:"
360 		       " %u, but zero tag_num\n", tag_size);
361 		return ERR_PTR(-EINVAL);
362 	}
363 
364 	se_sess = transport_alloc_session(sup_prot_ops);
365 	if (IS_ERR(se_sess))
366 		return se_sess;
367 
368 	rc = transport_alloc_session_tags(se_sess, tag_num, tag_size);
369 	if (rc < 0) {
370 		transport_free_session(se_sess);
371 		return ERR_PTR(-ENOMEM);
372 	}
373 
374 	return se_sess;
375 }
376 
377 /*
378  * Called with spin_lock_irqsave(&struct se_portal_group->session_lock called.
379  */
380 void __transport_register_session(
381 	struct se_portal_group *se_tpg,
382 	struct se_node_acl *se_nacl,
383 	struct se_session *se_sess,
384 	void *fabric_sess_ptr)
385 {
386 	const struct target_core_fabric_ops *tfo = se_tpg->se_tpg_tfo;
387 	unsigned char buf[PR_REG_ISID_LEN];
388 	unsigned long flags;
389 
390 	se_sess->se_tpg = se_tpg;
391 	se_sess->fabric_sess_ptr = fabric_sess_ptr;
392 	/*
393 	 * Used by struct se_node_acl's under ConfigFS to locate active se_session-t
394 	 *
395 	 * Only set for struct se_session's that will actually be moving I/O.
396 	 * eg: *NOT* discovery sessions.
397 	 */
398 	if (se_nacl) {
399 		/*
400 		 *
401 		 * Determine if fabric allows for T10-PI feature bits exposed to
402 		 * initiators for device backends with !dev->dev_attrib.pi_prot_type.
403 		 *
404 		 * If so, then always save prot_type on a per se_node_acl node
405 		 * basis and re-instate the previous sess_prot_type to avoid
406 		 * disabling PI from below any previously initiator side
407 		 * registered LUNs.
408 		 */
409 		if (se_nacl->saved_prot_type)
410 			se_sess->sess_prot_type = se_nacl->saved_prot_type;
411 		else if (tfo->tpg_check_prot_fabric_only)
412 			se_sess->sess_prot_type = se_nacl->saved_prot_type =
413 					tfo->tpg_check_prot_fabric_only(se_tpg);
414 		/*
415 		 * If the fabric module supports an ISID based TransportID,
416 		 * save this value in binary from the fabric I_T Nexus now.
417 		 */
418 		if (se_tpg->se_tpg_tfo->sess_get_initiator_sid != NULL) {
419 			memset(&buf[0], 0, PR_REG_ISID_LEN);
420 			se_tpg->se_tpg_tfo->sess_get_initiator_sid(se_sess,
421 					&buf[0], PR_REG_ISID_LEN);
422 			se_sess->sess_bin_isid = get_unaligned_be64(&buf[0]);
423 		}
424 
425 		spin_lock_irqsave(&se_nacl->nacl_sess_lock, flags);
426 		/*
427 		 * The se_nacl->nacl_sess pointer will be set to the
428 		 * last active I_T Nexus for each struct se_node_acl.
429 		 */
430 		se_nacl->nacl_sess = se_sess;
431 
432 		list_add_tail(&se_sess->sess_acl_list,
433 			      &se_nacl->acl_sess_list);
434 		spin_unlock_irqrestore(&se_nacl->nacl_sess_lock, flags);
435 	}
436 	list_add_tail(&se_sess->sess_list, &se_tpg->tpg_sess_list);
437 
438 	pr_debug("TARGET_CORE[%s]: Registered fabric_sess_ptr: %p\n",
439 		se_tpg->se_tpg_tfo->fabric_name, se_sess->fabric_sess_ptr);
440 }
441 EXPORT_SYMBOL(__transport_register_session);
442 
443 void transport_register_session(
444 	struct se_portal_group *se_tpg,
445 	struct se_node_acl *se_nacl,
446 	struct se_session *se_sess,
447 	void *fabric_sess_ptr)
448 {
449 	unsigned long flags;
450 
451 	spin_lock_irqsave(&se_tpg->session_lock, flags);
452 	__transport_register_session(se_tpg, se_nacl, se_sess, fabric_sess_ptr);
453 	spin_unlock_irqrestore(&se_tpg->session_lock, flags);
454 }
455 EXPORT_SYMBOL(transport_register_session);
456 
457 struct se_session *
458 target_setup_session(struct se_portal_group *tpg,
459 		     unsigned int tag_num, unsigned int tag_size,
460 		     enum target_prot_op prot_op,
461 		     const char *initiatorname, void *private,
462 		     int (*callback)(struct se_portal_group *,
463 				     struct se_session *, void *))
464 {
465 	struct target_cmd_counter *cmd_cnt;
466 	struct se_session *sess;
467 	int rc;
468 
469 	cmd_cnt = target_alloc_cmd_counter();
470 	if (!cmd_cnt)
471 		return ERR_PTR(-ENOMEM);
472 	/*
473 	 * If the fabric driver is using percpu-ida based pre allocation
474 	 * of I/O descriptor tags, go ahead and perform that setup now..
475 	 */
476 	if (tag_num != 0)
477 		sess = transport_init_session_tags(tag_num, tag_size, prot_op);
478 	else
479 		sess = transport_alloc_session(prot_op);
480 
481 	if (IS_ERR(sess)) {
482 		rc = PTR_ERR(sess);
483 		goto free_cnt;
484 	}
485 	sess->cmd_cnt = cmd_cnt;
486 
487 	sess->se_node_acl = core_tpg_check_initiator_node_acl(tpg,
488 					(unsigned char *)initiatorname);
489 	if (!sess->se_node_acl) {
490 		rc = -EACCES;
491 		goto free_sess;
492 	}
493 	/*
494 	 * Go ahead and perform any remaining fabric setup that is
495 	 * required before transport_register_session().
496 	 */
497 	if (callback != NULL) {
498 		rc = callback(tpg, sess, private);
499 		if (rc)
500 			goto free_sess;
501 	}
502 
503 	transport_register_session(tpg, sess->se_node_acl, sess, private);
504 	return sess;
505 
506 free_sess:
507 	transport_free_session(sess);
508 	return ERR_PTR(rc);
509 
510 free_cnt:
511 	target_free_cmd_counter(cmd_cnt);
512 	return ERR_PTR(rc);
513 }
514 EXPORT_SYMBOL(target_setup_session);
515 
516 ssize_t target_show_dynamic_sessions(struct se_portal_group *se_tpg, char *page)
517 {
518 	struct se_session *se_sess;
519 	ssize_t len = 0;
520 
521 	spin_lock_bh(&se_tpg->session_lock);
522 	list_for_each_entry(se_sess, &se_tpg->tpg_sess_list, sess_list) {
523 		if (!se_sess->se_node_acl)
524 			continue;
525 		if (!se_sess->se_node_acl->dynamic_node_acl)
526 			continue;
527 		if (strlen(se_sess->se_node_acl->initiatorname) + 1 + len > PAGE_SIZE)
528 			break;
529 
530 		len += snprintf(page + len, PAGE_SIZE - len, "%s\n",
531 				se_sess->se_node_acl->initiatorname);
532 		len += 1; /* Include NULL terminator */
533 	}
534 	spin_unlock_bh(&se_tpg->session_lock);
535 
536 	return len;
537 }
538 EXPORT_SYMBOL(target_show_dynamic_sessions);
539 
540 static void target_complete_nacl(struct kref *kref)
541 {
542 	struct se_node_acl *nacl = container_of(kref,
543 				struct se_node_acl, acl_kref);
544 	struct se_portal_group *se_tpg = nacl->se_tpg;
545 
546 	if (!nacl->dynamic_stop) {
547 		complete(&nacl->acl_free_comp);
548 		return;
549 	}
550 
551 	mutex_lock(&se_tpg->acl_node_mutex);
552 	list_del_init(&nacl->acl_list);
553 	mutex_unlock(&se_tpg->acl_node_mutex);
554 
555 	core_tpg_wait_for_nacl_pr_ref(nacl);
556 	core_free_device_list_for_node(nacl, se_tpg);
557 	kfree(nacl);
558 }
559 
560 void target_put_nacl(struct se_node_acl *nacl)
561 {
562 	kref_put(&nacl->acl_kref, target_complete_nacl);
563 }
564 EXPORT_SYMBOL(target_put_nacl);
565 
566 void transport_deregister_session_configfs(struct se_session *se_sess)
567 {
568 	struct se_node_acl *se_nacl;
569 	unsigned long flags;
570 	/*
571 	 * Used by struct se_node_acl's under ConfigFS to locate active struct se_session
572 	 */
573 	se_nacl = se_sess->se_node_acl;
574 	if (se_nacl) {
575 		spin_lock_irqsave(&se_nacl->nacl_sess_lock, flags);
576 		if (!list_empty(&se_sess->sess_acl_list))
577 			list_del_init(&se_sess->sess_acl_list);
578 		/*
579 		 * If the session list is empty, then clear the pointer.
580 		 * Otherwise, set the struct se_session pointer from the tail
581 		 * element of the per struct se_node_acl active session list.
582 		 */
583 		if (list_empty(&se_nacl->acl_sess_list))
584 			se_nacl->nacl_sess = NULL;
585 		else {
586 			se_nacl->nacl_sess = container_of(
587 					se_nacl->acl_sess_list.prev,
588 					struct se_session, sess_acl_list);
589 		}
590 		spin_unlock_irqrestore(&se_nacl->nacl_sess_lock, flags);
591 	}
592 }
593 EXPORT_SYMBOL(transport_deregister_session_configfs);
594 
595 void transport_free_session(struct se_session *se_sess)
596 {
597 	struct se_node_acl *se_nacl = se_sess->se_node_acl;
598 
599 	/*
600 	 * Drop the se_node_acl->nacl_kref obtained from within
601 	 * core_tpg_get_initiator_node_acl().
602 	 */
603 	if (se_nacl) {
604 		struct se_portal_group *se_tpg = se_nacl->se_tpg;
605 		const struct target_core_fabric_ops *se_tfo = se_tpg->se_tpg_tfo;
606 		unsigned long flags;
607 
608 		se_sess->se_node_acl = NULL;
609 
610 		/*
611 		 * Also determine if we need to drop the extra ->cmd_kref if
612 		 * it had been previously dynamically generated, and
613 		 * the endpoint is not caching dynamic ACLs.
614 		 */
615 		mutex_lock(&se_tpg->acl_node_mutex);
616 		if (se_nacl->dynamic_node_acl &&
617 		    !se_tfo->tpg_check_demo_mode_cache(se_tpg)) {
618 			spin_lock_irqsave(&se_nacl->nacl_sess_lock, flags);
619 			if (list_empty(&se_nacl->acl_sess_list))
620 				se_nacl->dynamic_stop = true;
621 			spin_unlock_irqrestore(&se_nacl->nacl_sess_lock, flags);
622 
623 			if (se_nacl->dynamic_stop)
624 				list_del_init(&se_nacl->acl_list);
625 		}
626 		mutex_unlock(&se_tpg->acl_node_mutex);
627 
628 		if (se_nacl->dynamic_stop)
629 			target_put_nacl(se_nacl);
630 
631 		target_put_nacl(se_nacl);
632 	}
633 	if (se_sess->sess_cmd_map) {
634 		sbitmap_queue_free(&se_sess->sess_tag_pool);
635 		kvfree(se_sess->sess_cmd_map);
636 	}
637 	if (se_sess->cmd_cnt)
638 		target_free_cmd_counter(se_sess->cmd_cnt);
639 	kmem_cache_free(se_sess_cache, se_sess);
640 }
641 EXPORT_SYMBOL(transport_free_session);
642 
643 static int target_release_res(struct se_device *dev, void *data)
644 {
645 	struct se_session *sess = data;
646 
647 	if (dev->reservation_holder == sess)
648 		target_release_reservation(dev);
649 	return 0;
650 }
651 
652 void transport_deregister_session(struct se_session *se_sess)
653 {
654 	struct se_portal_group *se_tpg = se_sess->se_tpg;
655 	unsigned long flags;
656 
657 	if (!se_tpg) {
658 		transport_free_session(se_sess);
659 		return;
660 	}
661 
662 	spin_lock_irqsave(&se_tpg->session_lock, flags);
663 	list_del(&se_sess->sess_list);
664 	se_sess->se_tpg = NULL;
665 	se_sess->fabric_sess_ptr = NULL;
666 	spin_unlock_irqrestore(&se_tpg->session_lock, flags);
667 
668 	/*
669 	 * Since the session is being removed, release SPC-2
670 	 * reservations held by the session that is disappearing.
671 	 */
672 	target_for_each_device(target_release_res, se_sess);
673 
674 	pr_debug("TARGET_CORE[%s]: Deregistered fabric_sess\n",
675 		se_tpg->se_tpg_tfo->fabric_name);
676 	/*
677 	 * If last kref is dropping now for an explicit NodeACL, awake sleeping
678 	 * ->acl_free_comp caller to wakeup configfs se_node_acl->acl_group
679 	 * removal context from within transport_free_session() code.
680 	 *
681 	 * For dynamic ACL, target_put_nacl() uses target_complete_nacl()
682 	 * to release all remaining generate_node_acl=1 created ACL resources.
683 	 */
684 
685 	transport_free_session(se_sess);
686 }
687 EXPORT_SYMBOL(transport_deregister_session);
688 
689 void target_remove_session(struct se_session *se_sess)
690 {
691 	transport_deregister_session_configfs(se_sess);
692 	transport_deregister_session(se_sess);
693 }
694 EXPORT_SYMBOL(target_remove_session);
695 
696 static void target_remove_from_state_list(struct se_cmd *cmd)
697 {
698 	struct se_device *dev = cmd->se_dev;
699 	unsigned long flags;
700 
701 	if (!dev)
702 		return;
703 
704 	spin_lock_irqsave(&dev->queues[cmd->cpuid].lock, flags);
705 	if (cmd->state_active) {
706 		list_del(&cmd->state_list);
707 		cmd->state_active = false;
708 	}
709 	spin_unlock_irqrestore(&dev->queues[cmd->cpuid].lock, flags);
710 }
711 
712 static void target_remove_from_tmr_list(struct se_cmd *cmd)
713 {
714 	struct se_device *dev = NULL;
715 	unsigned long flags;
716 
717 	if (cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
718 		dev = cmd->se_tmr_req->tmr_dev;
719 
720 	if (dev) {
721 		spin_lock_irqsave(&dev->se_tmr_lock, flags);
722 		if (cmd->se_tmr_req->tmr_dev)
723 			list_del_init(&cmd->se_tmr_req->tmr_list);
724 		spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
725 	}
726 }
727 /*
728  * This function is called by the target core after the target core has
729  * finished processing a SCSI command or SCSI TMF. Both the regular command
730  * processing code and the code for aborting commands can call this
731  * function. CMD_T_STOP is set if and only if another thread is waiting
732  * inside transport_wait_for_tasks() for t_transport_stop_comp.
733  */
734 static int transport_cmd_check_stop_to_fabric(struct se_cmd *cmd)
735 {
736 	unsigned long flags;
737 
738 	spin_lock_irqsave(&cmd->t_state_lock, flags);
739 	/*
740 	 * Determine if frontend context caller is requesting the stopping of
741 	 * this command for frontend exceptions.
742 	 */
743 	if (cmd->transport_state & CMD_T_STOP) {
744 		pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08llx\n",
745 			__func__, __LINE__, cmd->tag);
746 
747 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
748 
749 		complete_all(&cmd->t_transport_stop_comp);
750 		return 1;
751 	}
752 	cmd->transport_state &= ~CMD_T_ACTIVE;
753 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
754 
755 	/*
756 	 * Some fabric modules like tcm_loop can release their internally
757 	 * allocated I/O reference and struct se_cmd now.
758 	 *
759 	 * Fabric modules are expected to return '1' here if the se_cmd being
760 	 * passed is released at this point, or zero if not being released.
761 	 */
762 	return cmd->se_tfo->check_stop_free(cmd);
763 }
764 
765 static void transport_lun_remove_cmd(struct se_cmd *cmd)
766 {
767 	struct se_lun *lun = cmd->se_lun;
768 
769 	if (!lun)
770 		return;
771 
772 	target_remove_from_state_list(cmd);
773 	target_remove_from_tmr_list(cmd);
774 
775 	if (cmpxchg(&cmd->lun_ref_active, true, false))
776 		percpu_ref_put(&lun->lun_ref);
777 
778 	/*
779 	 * Clear struct se_cmd->se_lun before the handoff to FE.
780 	 */
781 	cmd->se_lun = NULL;
782 }
783 
784 static void target_complete_failure_work(struct work_struct *work)
785 {
786 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
787 
788 	transport_generic_request_failure(cmd, cmd->sense_reason);
789 }
790 
791 /*
792  * Used when asking transport to copy Sense Data from the underlying
793  * Linux/SCSI struct scsi_cmnd
794  */
795 static unsigned char *transport_get_sense_buffer(struct se_cmd *cmd)
796 {
797 	struct se_device *dev = cmd->se_dev;
798 
799 	WARN_ON(!cmd->se_lun);
800 
801 	if (!dev)
802 		return NULL;
803 
804 	if (cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION)
805 		return NULL;
806 
807 	cmd->scsi_sense_length = TRANSPORT_SENSE_BUFFER;
808 
809 	pr_debug("HBA_[%u]_PLUG[%s]: Requesting sense for SAM STATUS: 0x%02x\n",
810 		dev->se_hba->hba_id, dev->transport->name, cmd->scsi_status);
811 	return cmd->sense_buffer;
812 }
813 
814 void transport_copy_sense_to_cmd(struct se_cmd *cmd, unsigned char *sense)
815 {
816 	unsigned char *cmd_sense_buf;
817 	unsigned long flags;
818 
819 	spin_lock_irqsave(&cmd->t_state_lock, flags);
820 	cmd_sense_buf = transport_get_sense_buffer(cmd);
821 	if (!cmd_sense_buf) {
822 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
823 		return;
824 	}
825 
826 	cmd->se_cmd_flags |= SCF_TRANSPORT_TASK_SENSE;
827 	memcpy(cmd_sense_buf, sense, cmd->scsi_sense_length);
828 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
829 }
830 EXPORT_SYMBOL(transport_copy_sense_to_cmd);
831 
832 static void target_handle_abort(struct se_cmd *cmd)
833 {
834 	bool tas = cmd->transport_state & CMD_T_TAS;
835 	bool ack_kref = cmd->se_cmd_flags & SCF_ACK_KREF;
836 	int ret;
837 
838 	pr_debug("tag %#llx: send_abort_response = %d\n", cmd->tag, tas);
839 
840 	if (tas) {
841 		if (!(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)) {
842 			cmd->scsi_status = SAM_STAT_TASK_ABORTED;
843 			pr_debug("Setting SAM_STAT_TASK_ABORTED status for CDB: 0x%02x, ITT: 0x%08llx\n",
844 				 cmd->t_task_cdb[0], cmd->tag);
845 			trace_target_cmd_complete(cmd);
846 			ret = cmd->se_tfo->queue_status(cmd);
847 			if (ret) {
848 				transport_handle_queue_full(cmd, cmd->se_dev,
849 							    ret, false);
850 				return;
851 			}
852 		} else {
853 			cmd->se_tmr_req->response = TMR_FUNCTION_REJECTED;
854 			cmd->se_tfo->queue_tm_rsp(cmd);
855 		}
856 	} else {
857 		/*
858 		 * Allow the fabric driver to unmap any resources before
859 		 * releasing the descriptor via TFO->release_cmd().
860 		 */
861 		cmd->se_tfo->aborted_task(cmd);
862 		if (ack_kref)
863 			WARN_ON_ONCE(target_put_sess_cmd(cmd) != 0);
864 		/*
865 		 * To do: establish a unit attention condition on the I_T
866 		 * nexus associated with cmd. See also the paragraph "Aborting
867 		 * commands" in SAM.
868 		 */
869 	}
870 
871 	WARN_ON_ONCE(kref_read(&cmd->cmd_kref) == 0);
872 
873 	transport_lun_remove_cmd(cmd);
874 
875 	transport_cmd_check_stop_to_fabric(cmd);
876 }
877 
878 static void target_abort_work(struct work_struct *work)
879 {
880 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
881 
882 	target_handle_abort(cmd);
883 }
884 
885 static bool target_cmd_interrupted(struct se_cmd *cmd)
886 {
887 	int post_ret;
888 
889 	if (cmd->transport_state & CMD_T_ABORTED) {
890 		if (cmd->transport_complete_callback)
891 			cmd->transport_complete_callback(cmd, false, &post_ret);
892 		INIT_WORK(&cmd->work, target_abort_work);
893 		queue_work(target_completion_wq, &cmd->work);
894 		return true;
895 	} else if (cmd->transport_state & CMD_T_STOP) {
896 		if (cmd->transport_complete_callback)
897 			cmd->transport_complete_callback(cmd, false, &post_ret);
898 		complete_all(&cmd->t_transport_stop_comp);
899 		return true;
900 	}
901 
902 	return false;
903 }
904 
905 /* May be called from interrupt context so must not sleep. */
906 void target_complete_cmd_with_sense(struct se_cmd *cmd, u8 scsi_status,
907 				    sense_reason_t sense_reason)
908 {
909 	struct se_wwn *wwn = cmd->se_sess->se_tpg->se_tpg_wwn;
910 	int success, cpu;
911 	unsigned long flags;
912 
913 	if (target_cmd_interrupted(cmd))
914 		return;
915 
916 	cmd->scsi_status = scsi_status;
917 	cmd->sense_reason = sense_reason;
918 
919 	spin_lock_irqsave(&cmd->t_state_lock, flags);
920 	switch (cmd->scsi_status) {
921 	case SAM_STAT_CHECK_CONDITION:
922 		if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE)
923 			success = 1;
924 		else
925 			success = 0;
926 		break;
927 	default:
928 		success = 1;
929 		break;
930 	}
931 
932 	cmd->t_state = TRANSPORT_COMPLETE;
933 	cmd->transport_state |= (CMD_T_COMPLETE | CMD_T_ACTIVE);
934 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
935 
936 	INIT_WORK(&cmd->work, success ? target_complete_ok_work :
937 		  target_complete_failure_work);
938 
939 	if (!wwn || wwn->cmd_compl_affinity == SE_COMPL_AFFINITY_CPUID)
940 		cpu = cmd->cpuid;
941 	else
942 		cpu = wwn->cmd_compl_affinity;
943 
944 	queue_work_on(cpu, target_completion_wq, &cmd->work);
945 }
946 EXPORT_SYMBOL(target_complete_cmd_with_sense);
947 
948 void target_complete_cmd(struct se_cmd *cmd, u8 scsi_status)
949 {
950 	target_complete_cmd_with_sense(cmd, scsi_status, scsi_status ?
951 			      TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE :
952 			      TCM_NO_SENSE);
953 }
954 EXPORT_SYMBOL(target_complete_cmd);
955 
956 void target_set_cmd_data_length(struct se_cmd *cmd, int length)
957 {
958 	if (length < cmd->data_length) {
959 		if (cmd->se_cmd_flags & SCF_UNDERFLOW_BIT) {
960 			cmd->residual_count += cmd->data_length - length;
961 		} else {
962 			cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
963 			cmd->residual_count = cmd->data_length - length;
964 		}
965 
966 		cmd->data_length = length;
967 	}
968 }
969 EXPORT_SYMBOL(target_set_cmd_data_length);
970 
971 void target_complete_cmd_with_length(struct se_cmd *cmd, u8 scsi_status, int length)
972 {
973 	if (scsi_status == SAM_STAT_GOOD ||
974 	    cmd->se_cmd_flags & SCF_TREAT_READ_AS_NORMAL) {
975 		target_set_cmd_data_length(cmd, length);
976 	}
977 
978 	target_complete_cmd(cmd, scsi_status);
979 }
980 EXPORT_SYMBOL(target_complete_cmd_with_length);
981 
982 static void target_add_to_state_list(struct se_cmd *cmd)
983 {
984 	struct se_device *dev = cmd->se_dev;
985 	unsigned long flags;
986 
987 	spin_lock_irqsave(&dev->queues[cmd->cpuid].lock, flags);
988 	if (!cmd->state_active) {
989 		list_add_tail(&cmd->state_list,
990 			      &dev->queues[cmd->cpuid].state_list);
991 		cmd->state_active = true;
992 	}
993 	spin_unlock_irqrestore(&dev->queues[cmd->cpuid].lock, flags);
994 }
995 
996 /*
997  * Handle QUEUE_FULL / -EAGAIN and -ENOMEM status
998  */
999 static void transport_write_pending_qf(struct se_cmd *cmd);
1000 static void transport_complete_qf(struct se_cmd *cmd);
1001 
1002 void target_qf_do_work(struct work_struct *work)
1003 {
1004 	struct se_device *dev = container_of(work, struct se_device,
1005 					qf_work_queue);
1006 	LIST_HEAD(qf_cmd_list);
1007 	struct se_cmd *cmd, *cmd_tmp;
1008 
1009 	spin_lock_irq(&dev->qf_cmd_lock);
1010 	list_splice_init(&dev->qf_cmd_list, &qf_cmd_list);
1011 	spin_unlock_irq(&dev->qf_cmd_lock);
1012 
1013 	list_for_each_entry_safe(cmd, cmd_tmp, &qf_cmd_list, se_qf_node) {
1014 		list_del(&cmd->se_qf_node);
1015 		atomic_dec_mb(&dev->dev_qf_count);
1016 
1017 		pr_debug("Processing %s cmd: %p QUEUE_FULL in work queue"
1018 			" context: %s\n", cmd->se_tfo->fabric_name, cmd,
1019 			(cmd->t_state == TRANSPORT_COMPLETE_QF_OK) ? "COMPLETE_OK" :
1020 			(cmd->t_state == TRANSPORT_COMPLETE_QF_WP) ? "WRITE_PENDING"
1021 			: "UNKNOWN");
1022 
1023 		if (cmd->t_state == TRANSPORT_COMPLETE_QF_WP)
1024 			transport_write_pending_qf(cmd);
1025 		else if (cmd->t_state == TRANSPORT_COMPLETE_QF_OK ||
1026 			 cmd->t_state == TRANSPORT_COMPLETE_QF_ERR)
1027 			transport_complete_qf(cmd);
1028 	}
1029 }
1030 
1031 unsigned char *transport_dump_cmd_direction(struct se_cmd *cmd)
1032 {
1033 	switch (cmd->data_direction) {
1034 	case DMA_NONE:
1035 		return "NONE";
1036 	case DMA_FROM_DEVICE:
1037 		return "READ";
1038 	case DMA_TO_DEVICE:
1039 		return "WRITE";
1040 	case DMA_BIDIRECTIONAL:
1041 		return "BIDI";
1042 	default:
1043 		break;
1044 	}
1045 
1046 	return "UNKNOWN";
1047 }
1048 
1049 void transport_dump_dev_state(
1050 	struct se_device *dev,
1051 	char *b,
1052 	int *bl)
1053 {
1054 	*bl += sprintf(b + *bl, "Status: ");
1055 	if (dev->export_count)
1056 		*bl += sprintf(b + *bl, "ACTIVATED");
1057 	else
1058 		*bl += sprintf(b + *bl, "DEACTIVATED");
1059 
1060 	*bl += sprintf(b + *bl, "  Max Queue Depth: %d", dev->queue_depth);
1061 	*bl += sprintf(b + *bl, "  SectorSize: %u  HwMaxSectors: %u\n",
1062 		dev->dev_attrib.block_size,
1063 		dev->dev_attrib.hw_max_sectors);
1064 	*bl += sprintf(b + *bl, "        ");
1065 }
1066 
1067 void transport_dump_vpd_proto_id(
1068 	struct t10_vpd *vpd,
1069 	unsigned char *p_buf,
1070 	int p_buf_len)
1071 {
1072 	unsigned char buf[VPD_TMP_BUF_SIZE];
1073 	int len;
1074 
1075 	memset(buf, 0, VPD_TMP_BUF_SIZE);
1076 	len = sprintf(buf, "T10 VPD Protocol Identifier: ");
1077 
1078 	switch (vpd->protocol_identifier) {
1079 	case 0x00:
1080 		sprintf(buf+len, "Fibre Channel\n");
1081 		break;
1082 	case 0x10:
1083 		sprintf(buf+len, "Parallel SCSI\n");
1084 		break;
1085 	case 0x20:
1086 		sprintf(buf+len, "SSA\n");
1087 		break;
1088 	case 0x30:
1089 		sprintf(buf+len, "IEEE 1394\n");
1090 		break;
1091 	case 0x40:
1092 		sprintf(buf+len, "SCSI Remote Direct Memory Access"
1093 				" Protocol\n");
1094 		break;
1095 	case 0x50:
1096 		sprintf(buf+len, "Internet SCSI (iSCSI)\n");
1097 		break;
1098 	case 0x60:
1099 		sprintf(buf+len, "SAS Serial SCSI Protocol\n");
1100 		break;
1101 	case 0x70:
1102 		sprintf(buf+len, "Automation/Drive Interface Transport"
1103 				" Protocol\n");
1104 		break;
1105 	case 0x80:
1106 		sprintf(buf+len, "AT Attachment Interface ATA/ATAPI\n");
1107 		break;
1108 	default:
1109 		sprintf(buf+len, "Unknown 0x%02x\n",
1110 				vpd->protocol_identifier);
1111 		break;
1112 	}
1113 
1114 	if (p_buf)
1115 		strncpy(p_buf, buf, p_buf_len);
1116 	else
1117 		pr_debug("%s", buf);
1118 }
1119 
1120 void
1121 transport_set_vpd_proto_id(struct t10_vpd *vpd, unsigned char *page_83)
1122 {
1123 	/*
1124 	 * Check if the Protocol Identifier Valid (PIV) bit is set..
1125 	 *
1126 	 * from spc3r23.pdf section 7.5.1
1127 	 */
1128 	 if (page_83[1] & 0x80) {
1129 		vpd->protocol_identifier = (page_83[0] & 0xf0);
1130 		vpd->protocol_identifier_set = 1;
1131 		transport_dump_vpd_proto_id(vpd, NULL, 0);
1132 	}
1133 }
1134 EXPORT_SYMBOL(transport_set_vpd_proto_id);
1135 
1136 int transport_dump_vpd_assoc(
1137 	struct t10_vpd *vpd,
1138 	unsigned char *p_buf,
1139 	int p_buf_len)
1140 {
1141 	unsigned char buf[VPD_TMP_BUF_SIZE];
1142 	int ret = 0;
1143 	int len;
1144 
1145 	memset(buf, 0, VPD_TMP_BUF_SIZE);
1146 	len = sprintf(buf, "T10 VPD Identifier Association: ");
1147 
1148 	switch (vpd->association) {
1149 	case 0x00:
1150 		sprintf(buf+len, "addressed logical unit\n");
1151 		break;
1152 	case 0x10:
1153 		sprintf(buf+len, "target port\n");
1154 		break;
1155 	case 0x20:
1156 		sprintf(buf+len, "SCSI target device\n");
1157 		break;
1158 	default:
1159 		sprintf(buf+len, "Unknown 0x%02x\n", vpd->association);
1160 		ret = -EINVAL;
1161 		break;
1162 	}
1163 
1164 	if (p_buf)
1165 		strncpy(p_buf, buf, p_buf_len);
1166 	else
1167 		pr_debug("%s", buf);
1168 
1169 	return ret;
1170 }
1171 
1172 int transport_set_vpd_assoc(struct t10_vpd *vpd, unsigned char *page_83)
1173 {
1174 	/*
1175 	 * The VPD identification association..
1176 	 *
1177 	 * from spc3r23.pdf Section 7.6.3.1 Table 297
1178 	 */
1179 	vpd->association = (page_83[1] & 0x30);
1180 	return transport_dump_vpd_assoc(vpd, NULL, 0);
1181 }
1182 EXPORT_SYMBOL(transport_set_vpd_assoc);
1183 
1184 int transport_dump_vpd_ident_type(
1185 	struct t10_vpd *vpd,
1186 	unsigned char *p_buf,
1187 	int p_buf_len)
1188 {
1189 	unsigned char buf[VPD_TMP_BUF_SIZE];
1190 	int ret = 0;
1191 	int len;
1192 
1193 	memset(buf, 0, VPD_TMP_BUF_SIZE);
1194 	len = sprintf(buf, "T10 VPD Identifier Type: ");
1195 
1196 	switch (vpd->device_identifier_type) {
1197 	case 0x00:
1198 		sprintf(buf+len, "Vendor specific\n");
1199 		break;
1200 	case 0x01:
1201 		sprintf(buf+len, "T10 Vendor ID based\n");
1202 		break;
1203 	case 0x02:
1204 		sprintf(buf+len, "EUI-64 based\n");
1205 		break;
1206 	case 0x03:
1207 		sprintf(buf+len, "NAA\n");
1208 		break;
1209 	case 0x04:
1210 		sprintf(buf+len, "Relative target port identifier\n");
1211 		break;
1212 	case 0x08:
1213 		sprintf(buf+len, "SCSI name string\n");
1214 		break;
1215 	default:
1216 		sprintf(buf+len, "Unsupported: 0x%02x\n",
1217 				vpd->device_identifier_type);
1218 		ret = -EINVAL;
1219 		break;
1220 	}
1221 
1222 	if (p_buf) {
1223 		if (p_buf_len < strlen(buf)+1)
1224 			return -EINVAL;
1225 		strncpy(p_buf, buf, p_buf_len);
1226 	} else {
1227 		pr_debug("%s", buf);
1228 	}
1229 
1230 	return ret;
1231 }
1232 
1233 int transport_set_vpd_ident_type(struct t10_vpd *vpd, unsigned char *page_83)
1234 {
1235 	/*
1236 	 * The VPD identifier type..
1237 	 *
1238 	 * from spc3r23.pdf Section 7.6.3.1 Table 298
1239 	 */
1240 	vpd->device_identifier_type = (page_83[1] & 0x0f);
1241 	return transport_dump_vpd_ident_type(vpd, NULL, 0);
1242 }
1243 EXPORT_SYMBOL(transport_set_vpd_ident_type);
1244 
1245 int transport_dump_vpd_ident(
1246 	struct t10_vpd *vpd,
1247 	unsigned char *p_buf,
1248 	int p_buf_len)
1249 {
1250 	unsigned char buf[VPD_TMP_BUF_SIZE];
1251 	int ret = 0;
1252 
1253 	memset(buf, 0, VPD_TMP_BUF_SIZE);
1254 
1255 	switch (vpd->device_identifier_code_set) {
1256 	case 0x01: /* Binary */
1257 		snprintf(buf, sizeof(buf),
1258 			"T10 VPD Binary Device Identifier: %s\n",
1259 			&vpd->device_identifier[0]);
1260 		break;
1261 	case 0x02: /* ASCII */
1262 		snprintf(buf, sizeof(buf),
1263 			"T10 VPD ASCII Device Identifier: %s\n",
1264 			&vpd->device_identifier[0]);
1265 		break;
1266 	case 0x03: /* UTF-8 */
1267 		snprintf(buf, sizeof(buf),
1268 			"T10 VPD UTF-8 Device Identifier: %s\n",
1269 			&vpd->device_identifier[0]);
1270 		break;
1271 	default:
1272 		sprintf(buf, "T10 VPD Device Identifier encoding unsupported:"
1273 			" 0x%02x", vpd->device_identifier_code_set);
1274 		ret = -EINVAL;
1275 		break;
1276 	}
1277 
1278 	if (p_buf)
1279 		strncpy(p_buf, buf, p_buf_len);
1280 	else
1281 		pr_debug("%s", buf);
1282 
1283 	return ret;
1284 }
1285 
1286 int
1287 transport_set_vpd_ident(struct t10_vpd *vpd, unsigned char *page_83)
1288 {
1289 	static const char hex_str[] = "0123456789abcdef";
1290 	int j = 0, i = 4; /* offset to start of the identifier */
1291 
1292 	/*
1293 	 * The VPD Code Set (encoding)
1294 	 *
1295 	 * from spc3r23.pdf Section 7.6.3.1 Table 296
1296 	 */
1297 	vpd->device_identifier_code_set = (page_83[0] & 0x0f);
1298 	switch (vpd->device_identifier_code_set) {
1299 	case 0x01: /* Binary */
1300 		vpd->device_identifier[j++] =
1301 				hex_str[vpd->device_identifier_type];
1302 		while (i < (4 + page_83[3])) {
1303 			vpd->device_identifier[j++] =
1304 				hex_str[(page_83[i] & 0xf0) >> 4];
1305 			vpd->device_identifier[j++] =
1306 				hex_str[page_83[i] & 0x0f];
1307 			i++;
1308 		}
1309 		break;
1310 	case 0x02: /* ASCII */
1311 	case 0x03: /* UTF-8 */
1312 		while (i < (4 + page_83[3]))
1313 			vpd->device_identifier[j++] = page_83[i++];
1314 		break;
1315 	default:
1316 		break;
1317 	}
1318 
1319 	return transport_dump_vpd_ident(vpd, NULL, 0);
1320 }
1321 EXPORT_SYMBOL(transport_set_vpd_ident);
1322 
1323 static sense_reason_t
1324 target_check_max_data_sg_nents(struct se_cmd *cmd, struct se_device *dev,
1325 			       unsigned int size)
1326 {
1327 	u32 mtl;
1328 
1329 	if (!cmd->se_tfo->max_data_sg_nents)
1330 		return TCM_NO_SENSE;
1331 	/*
1332 	 * Check if fabric enforced maximum SGL entries per I/O descriptor
1333 	 * exceeds se_cmd->data_length.  If true, set SCF_UNDERFLOW_BIT +
1334 	 * residual_count and reduce original cmd->data_length to maximum
1335 	 * length based on single PAGE_SIZE entry scatter-lists.
1336 	 */
1337 	mtl = (cmd->se_tfo->max_data_sg_nents * PAGE_SIZE);
1338 	if (cmd->data_length > mtl) {
1339 		/*
1340 		 * If an existing CDB overflow is present, calculate new residual
1341 		 * based on CDB size minus fabric maximum transfer length.
1342 		 *
1343 		 * If an existing CDB underflow is present, calculate new residual
1344 		 * based on original cmd->data_length minus fabric maximum transfer
1345 		 * length.
1346 		 *
1347 		 * Otherwise, set the underflow residual based on cmd->data_length
1348 		 * minus fabric maximum transfer length.
1349 		 */
1350 		if (cmd->se_cmd_flags & SCF_OVERFLOW_BIT) {
1351 			cmd->residual_count = (size - mtl);
1352 		} else if (cmd->se_cmd_flags & SCF_UNDERFLOW_BIT) {
1353 			u32 orig_dl = size + cmd->residual_count;
1354 			cmd->residual_count = (orig_dl - mtl);
1355 		} else {
1356 			cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
1357 			cmd->residual_count = (cmd->data_length - mtl);
1358 		}
1359 		cmd->data_length = mtl;
1360 		/*
1361 		 * Reset sbc_check_prot() calculated protection payload
1362 		 * length based upon the new smaller MTL.
1363 		 */
1364 		if (cmd->prot_length) {
1365 			u32 sectors = (mtl / dev->dev_attrib.block_size);
1366 			cmd->prot_length = dev->prot_length * sectors;
1367 		}
1368 	}
1369 	return TCM_NO_SENSE;
1370 }
1371 
1372 /**
1373  * target_cmd_size_check - Check whether there will be a residual.
1374  * @cmd: SCSI command.
1375  * @size: Data buffer size derived from CDB. The data buffer size provided by
1376  *   the SCSI transport driver is available in @cmd->data_length.
1377  *
1378  * Compare the data buffer size from the CDB with the data buffer limit from the transport
1379  * header. Set @cmd->residual_count and SCF_OVERFLOW_BIT or SCF_UNDERFLOW_BIT if necessary.
1380  *
1381  * Note: target drivers set @cmd->data_length by calling __target_init_cmd().
1382  *
1383  * Return: TCM_NO_SENSE
1384  */
1385 sense_reason_t
1386 target_cmd_size_check(struct se_cmd *cmd, unsigned int size)
1387 {
1388 	struct se_device *dev = cmd->se_dev;
1389 
1390 	if (cmd->unknown_data_length) {
1391 		cmd->data_length = size;
1392 	} else if (size != cmd->data_length) {
1393 		pr_warn_ratelimited("TARGET_CORE[%s]: Expected Transfer Length:"
1394 			" %u does not match SCSI CDB Length: %u for SAM Opcode:"
1395 			" 0x%02x\n", cmd->se_tfo->fabric_name,
1396 				cmd->data_length, size, cmd->t_task_cdb[0]);
1397 		/*
1398 		 * For READ command for the overflow case keep the existing
1399 		 * fabric provided ->data_length. Otherwise for the underflow
1400 		 * case, reset ->data_length to the smaller SCSI expected data
1401 		 * transfer length.
1402 		 */
1403 		if (size > cmd->data_length) {
1404 			cmd->se_cmd_flags |= SCF_OVERFLOW_BIT;
1405 			cmd->residual_count = (size - cmd->data_length);
1406 		} else {
1407 			cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
1408 			cmd->residual_count = (cmd->data_length - size);
1409 			/*
1410 			 * Do not truncate ->data_length for WRITE command to
1411 			 * dump all payload
1412 			 */
1413 			if (cmd->data_direction == DMA_FROM_DEVICE) {
1414 				cmd->data_length = size;
1415 			}
1416 		}
1417 
1418 		if (cmd->data_direction == DMA_TO_DEVICE) {
1419 			if (cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) {
1420 				pr_err_ratelimited("Rejecting underflow/overflow"
1421 						   " for WRITE data CDB\n");
1422 				return TCM_INVALID_FIELD_IN_COMMAND_IU;
1423 			}
1424 			/*
1425 			 * Some fabric drivers like iscsi-target still expect to
1426 			 * always reject overflow writes.  Reject this case until
1427 			 * full fabric driver level support for overflow writes
1428 			 * is introduced tree-wide.
1429 			 */
1430 			if (size > cmd->data_length) {
1431 				pr_err_ratelimited("Rejecting overflow for"
1432 						   " WRITE control CDB\n");
1433 				return TCM_INVALID_CDB_FIELD;
1434 			}
1435 		}
1436 	}
1437 
1438 	return target_check_max_data_sg_nents(cmd, dev, size);
1439 
1440 }
1441 
1442 /*
1443  * Used by fabric modules containing a local struct se_cmd within their
1444  * fabric dependent per I/O descriptor.
1445  *
1446  * Preserves the value of @cmd->tag.
1447  */
1448 void __target_init_cmd(struct se_cmd *cmd,
1449 		       const struct target_core_fabric_ops *tfo,
1450 		       struct se_session *se_sess, u32 data_length,
1451 		       int data_direction, int task_attr,
1452 		       unsigned char *sense_buffer, u64 unpacked_lun,
1453 		       struct target_cmd_counter *cmd_cnt)
1454 {
1455 	INIT_LIST_HEAD(&cmd->se_delayed_node);
1456 	INIT_LIST_HEAD(&cmd->se_qf_node);
1457 	INIT_LIST_HEAD(&cmd->state_list);
1458 	init_completion(&cmd->t_transport_stop_comp);
1459 	cmd->free_compl = NULL;
1460 	cmd->abrt_compl = NULL;
1461 	spin_lock_init(&cmd->t_state_lock);
1462 	INIT_WORK(&cmd->work, NULL);
1463 	kref_init(&cmd->cmd_kref);
1464 
1465 	cmd->t_task_cdb = &cmd->__t_task_cdb[0];
1466 	cmd->se_tfo = tfo;
1467 	cmd->se_sess = se_sess;
1468 	cmd->data_length = data_length;
1469 	cmd->data_direction = data_direction;
1470 	cmd->sam_task_attr = task_attr;
1471 	cmd->sense_buffer = sense_buffer;
1472 	cmd->orig_fe_lun = unpacked_lun;
1473 	cmd->cmd_cnt = cmd_cnt;
1474 
1475 	if (!(cmd->se_cmd_flags & SCF_USE_CPUID))
1476 		cmd->cpuid = raw_smp_processor_id();
1477 
1478 	cmd->state_active = false;
1479 }
1480 EXPORT_SYMBOL(__target_init_cmd);
1481 
1482 static sense_reason_t
1483 transport_check_alloc_task_attr(struct se_cmd *cmd)
1484 {
1485 	struct se_device *dev = cmd->se_dev;
1486 
1487 	/*
1488 	 * Check if SAM Task Attribute emulation is enabled for this
1489 	 * struct se_device storage object
1490 	 */
1491 	if (dev->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
1492 		return 0;
1493 
1494 	if (cmd->sam_task_attr == TCM_ACA_TAG) {
1495 		pr_debug("SAM Task Attribute ACA"
1496 			" emulation is not supported\n");
1497 		return TCM_INVALID_CDB_FIELD;
1498 	}
1499 
1500 	return 0;
1501 }
1502 
1503 sense_reason_t
1504 target_cmd_init_cdb(struct se_cmd *cmd, unsigned char *cdb, gfp_t gfp)
1505 {
1506 	sense_reason_t ret;
1507 
1508 	/*
1509 	 * Ensure that the received CDB is less than the max (252 + 8) bytes
1510 	 * for VARIABLE_LENGTH_CMD
1511 	 */
1512 	if (scsi_command_size(cdb) > SCSI_MAX_VARLEN_CDB_SIZE) {
1513 		pr_err("Received SCSI CDB with command_size: %d that"
1514 			" exceeds SCSI_MAX_VARLEN_CDB_SIZE: %d\n",
1515 			scsi_command_size(cdb), SCSI_MAX_VARLEN_CDB_SIZE);
1516 		ret = TCM_INVALID_CDB_FIELD;
1517 		goto err;
1518 	}
1519 	/*
1520 	 * If the received CDB is larger than TCM_MAX_COMMAND_SIZE,
1521 	 * allocate the additional extended CDB buffer now..  Otherwise
1522 	 * setup the pointer from __t_task_cdb to t_task_cdb.
1523 	 */
1524 	if (scsi_command_size(cdb) > sizeof(cmd->__t_task_cdb)) {
1525 		cmd->t_task_cdb = kzalloc(scsi_command_size(cdb), gfp);
1526 		if (!cmd->t_task_cdb) {
1527 			pr_err("Unable to allocate cmd->t_task_cdb"
1528 				" %u > sizeof(cmd->__t_task_cdb): %lu ops\n",
1529 				scsi_command_size(cdb),
1530 				(unsigned long)sizeof(cmd->__t_task_cdb));
1531 			ret = TCM_OUT_OF_RESOURCES;
1532 			goto err;
1533 		}
1534 	}
1535 	/*
1536 	 * Copy the original CDB into cmd->
1537 	 */
1538 	memcpy(cmd->t_task_cdb, cdb, scsi_command_size(cdb));
1539 
1540 	trace_target_sequencer_start(cmd);
1541 	return 0;
1542 
1543 err:
1544 	/*
1545 	 * Copy the CDB here to allow trace_target_cmd_complete() to
1546 	 * print the cdb to the trace buffers.
1547 	 */
1548 	memcpy(cmd->t_task_cdb, cdb, min(scsi_command_size(cdb),
1549 					 (unsigned int)TCM_MAX_COMMAND_SIZE));
1550 	return ret;
1551 }
1552 EXPORT_SYMBOL(target_cmd_init_cdb);
1553 
1554 sense_reason_t
1555 target_cmd_parse_cdb(struct se_cmd *cmd)
1556 {
1557 	struct se_device *dev = cmd->se_dev;
1558 	sense_reason_t ret;
1559 
1560 	ret = dev->transport->parse_cdb(cmd);
1561 	if (ret == TCM_UNSUPPORTED_SCSI_OPCODE)
1562 		pr_debug_ratelimited("%s/%s: Unsupported SCSI Opcode 0x%02x, sending CHECK_CONDITION.\n",
1563 				     cmd->se_tfo->fabric_name,
1564 				     cmd->se_sess->se_node_acl->initiatorname,
1565 				     cmd->t_task_cdb[0]);
1566 	if (ret)
1567 		return ret;
1568 
1569 	ret = transport_check_alloc_task_attr(cmd);
1570 	if (ret)
1571 		return ret;
1572 
1573 	cmd->se_cmd_flags |= SCF_SUPPORTED_SAM_OPCODE;
1574 	atomic_long_inc(&cmd->se_lun->lun_stats.cmd_pdus);
1575 	return 0;
1576 }
1577 EXPORT_SYMBOL(target_cmd_parse_cdb);
1578 
1579 /*
1580  * Used by fabric module frontends to queue tasks directly.
1581  * May only be used from process context.
1582  */
1583 int transport_handle_cdb_direct(
1584 	struct se_cmd *cmd)
1585 {
1586 	sense_reason_t ret;
1587 
1588 	might_sleep();
1589 
1590 	if (!cmd->se_lun) {
1591 		dump_stack();
1592 		pr_err("cmd->se_lun is NULL\n");
1593 		return -EINVAL;
1594 	}
1595 
1596 	/*
1597 	 * Set TRANSPORT_NEW_CMD state and CMD_T_ACTIVE to ensure that
1598 	 * outstanding descriptors are handled correctly during shutdown via
1599 	 * transport_wait_for_tasks()
1600 	 *
1601 	 * Also, we don't take cmd->t_state_lock here as we only expect
1602 	 * this to be called for initial descriptor submission.
1603 	 */
1604 	cmd->t_state = TRANSPORT_NEW_CMD;
1605 	cmd->transport_state |= CMD_T_ACTIVE;
1606 
1607 	/*
1608 	 * transport_generic_new_cmd() is already handling QUEUE_FULL,
1609 	 * so follow TRANSPORT_NEW_CMD processing thread context usage
1610 	 * and call transport_generic_request_failure() if necessary..
1611 	 */
1612 	ret = transport_generic_new_cmd(cmd);
1613 	if (ret)
1614 		transport_generic_request_failure(cmd, ret);
1615 	return 0;
1616 }
1617 EXPORT_SYMBOL(transport_handle_cdb_direct);
1618 
1619 sense_reason_t
1620 transport_generic_map_mem_to_cmd(struct se_cmd *cmd, struct scatterlist *sgl,
1621 		u32 sgl_count, struct scatterlist *sgl_bidi, u32 sgl_bidi_count)
1622 {
1623 	if (!sgl || !sgl_count)
1624 		return 0;
1625 
1626 	/*
1627 	 * Reject SCSI data overflow with map_mem_to_cmd() as incoming
1628 	 * scatterlists already have been set to follow what the fabric
1629 	 * passes for the original expected data transfer length.
1630 	 */
1631 	if (cmd->se_cmd_flags & SCF_OVERFLOW_BIT) {
1632 		pr_warn("Rejecting SCSI DATA overflow for fabric using"
1633 			" SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC\n");
1634 		return TCM_INVALID_CDB_FIELD;
1635 	}
1636 
1637 	cmd->t_data_sg = sgl;
1638 	cmd->t_data_nents = sgl_count;
1639 	cmd->t_bidi_data_sg = sgl_bidi;
1640 	cmd->t_bidi_data_nents = sgl_bidi_count;
1641 
1642 	cmd->se_cmd_flags |= SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC;
1643 	return 0;
1644 }
1645 
1646 /**
1647  * target_init_cmd - initialize se_cmd
1648  * @se_cmd: command descriptor to init
1649  * @se_sess: associated se_sess for endpoint
1650  * @sense: pointer to SCSI sense buffer
1651  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1652  * @data_length: fabric expected data transfer length
1653  * @task_attr: SAM task attribute
1654  * @data_dir: DMA data direction
1655  * @flags: flags for command submission from target_sc_flags_tables
1656  *
1657  * Task tags are supported if the caller has set @se_cmd->tag.
1658  *
1659  * Returns:
1660  *	- less than zero to signal active I/O shutdown failure.
1661  *	- zero on success.
1662  *
1663  * If the fabric driver calls target_stop_session, then it must check the
1664  * return code and handle failures. This will never fail for other drivers,
1665  * and the return code can be ignored.
1666  */
1667 int target_init_cmd(struct se_cmd *se_cmd, struct se_session *se_sess,
1668 		    unsigned char *sense, u64 unpacked_lun,
1669 		    u32 data_length, int task_attr, int data_dir, int flags)
1670 {
1671 	struct se_portal_group *se_tpg;
1672 
1673 	se_tpg = se_sess->se_tpg;
1674 	BUG_ON(!se_tpg);
1675 	BUG_ON(se_cmd->se_tfo || se_cmd->se_sess);
1676 
1677 	if (flags & TARGET_SCF_USE_CPUID)
1678 		se_cmd->se_cmd_flags |= SCF_USE_CPUID;
1679 	/*
1680 	 * Signal bidirectional data payloads to target-core
1681 	 */
1682 	if (flags & TARGET_SCF_BIDI_OP)
1683 		se_cmd->se_cmd_flags |= SCF_BIDI;
1684 
1685 	if (flags & TARGET_SCF_UNKNOWN_SIZE)
1686 		se_cmd->unknown_data_length = 1;
1687 	/*
1688 	 * Initialize se_cmd for target operation.  From this point
1689 	 * exceptions are handled by sending exception status via
1690 	 * target_core_fabric_ops->queue_status() callback
1691 	 */
1692 	__target_init_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess, data_length,
1693 			  data_dir, task_attr, sense, unpacked_lun,
1694 			  se_sess->cmd_cnt);
1695 
1696 	/*
1697 	 * Obtain struct se_cmd->cmd_kref reference. A second kref_get here is
1698 	 * necessary for fabrics using TARGET_SCF_ACK_KREF that expect a second
1699 	 * kref_put() to happen during fabric packet acknowledgement.
1700 	 */
1701 	return target_get_sess_cmd(se_cmd, flags & TARGET_SCF_ACK_KREF);
1702 }
1703 EXPORT_SYMBOL_GPL(target_init_cmd);
1704 
1705 /**
1706  * target_submit_prep - prepare cmd for submission
1707  * @se_cmd: command descriptor to prep
1708  * @cdb: pointer to SCSI CDB
1709  * @sgl: struct scatterlist memory for unidirectional mapping
1710  * @sgl_count: scatterlist count for unidirectional mapping
1711  * @sgl_bidi: struct scatterlist memory for bidirectional READ mapping
1712  * @sgl_bidi_count: scatterlist count for bidirectional READ mapping
1713  * @sgl_prot: struct scatterlist memory protection information
1714  * @sgl_prot_count: scatterlist count for protection information
1715  * @gfp: gfp allocation type
1716  *
1717  * Returns:
1718  *	- less than zero to signal failure.
1719  *	- zero on success.
1720  *
1721  * If failure is returned, lio will the callers queue_status to complete
1722  * the cmd.
1723  */
1724 int target_submit_prep(struct se_cmd *se_cmd, unsigned char *cdb,
1725 		       struct scatterlist *sgl, u32 sgl_count,
1726 		       struct scatterlist *sgl_bidi, u32 sgl_bidi_count,
1727 		       struct scatterlist *sgl_prot, u32 sgl_prot_count,
1728 		       gfp_t gfp)
1729 {
1730 	sense_reason_t rc;
1731 
1732 	rc = target_cmd_init_cdb(se_cmd, cdb, gfp);
1733 	if (rc)
1734 		goto send_cc_direct;
1735 
1736 	/*
1737 	 * Locate se_lun pointer and attach it to struct se_cmd
1738 	 */
1739 	rc = transport_lookup_cmd_lun(se_cmd);
1740 	if (rc)
1741 		goto send_cc_direct;
1742 
1743 	rc = target_cmd_parse_cdb(se_cmd);
1744 	if (rc != 0)
1745 		goto generic_fail;
1746 
1747 	/*
1748 	 * Save pointers for SGLs containing protection information,
1749 	 * if present.
1750 	 */
1751 	if (sgl_prot_count) {
1752 		se_cmd->t_prot_sg = sgl_prot;
1753 		se_cmd->t_prot_nents = sgl_prot_count;
1754 		se_cmd->se_cmd_flags |= SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC;
1755 	}
1756 
1757 	/*
1758 	 * When a non zero sgl_count has been passed perform SGL passthrough
1759 	 * mapping for pre-allocated fabric memory instead of having target
1760 	 * core perform an internal SGL allocation..
1761 	 */
1762 	if (sgl_count != 0) {
1763 		BUG_ON(!sgl);
1764 
1765 		rc = transport_generic_map_mem_to_cmd(se_cmd, sgl, sgl_count,
1766 				sgl_bidi, sgl_bidi_count);
1767 		if (rc != 0)
1768 			goto generic_fail;
1769 	}
1770 
1771 	return 0;
1772 
1773 send_cc_direct:
1774 	transport_send_check_condition_and_sense(se_cmd, rc, 0);
1775 	target_put_sess_cmd(se_cmd);
1776 	return -EIO;
1777 
1778 generic_fail:
1779 	transport_generic_request_failure(se_cmd, rc);
1780 	return -EIO;
1781 }
1782 EXPORT_SYMBOL_GPL(target_submit_prep);
1783 
1784 /**
1785  * target_submit - perform final initialization and submit cmd to LIO core
1786  * @se_cmd: command descriptor to submit
1787  *
1788  * target_submit_prep must have been called on the cmd, and this must be
1789  * called from process context.
1790  */
1791 void target_submit(struct se_cmd *se_cmd)
1792 {
1793 	struct scatterlist *sgl = se_cmd->t_data_sg;
1794 	unsigned char *buf = NULL;
1795 
1796 	might_sleep();
1797 
1798 	if (se_cmd->t_data_nents != 0) {
1799 		BUG_ON(!sgl);
1800 		/*
1801 		 * A work-around for tcm_loop as some userspace code via
1802 		 * scsi-generic do not memset their associated read buffers,
1803 		 * so go ahead and do that here for type non-data CDBs.  Also
1804 		 * note that this is currently guaranteed to be a single SGL
1805 		 * for this case by target core in target_setup_cmd_from_cdb()
1806 		 * -> transport_generic_cmd_sequencer().
1807 		 */
1808 		if (!(se_cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) &&
1809 		     se_cmd->data_direction == DMA_FROM_DEVICE) {
1810 			if (sgl)
1811 				buf = kmap(sg_page(sgl)) + sgl->offset;
1812 
1813 			if (buf) {
1814 				memset(buf, 0, sgl->length);
1815 				kunmap(sg_page(sgl));
1816 			}
1817 		}
1818 
1819 	}
1820 
1821 	/*
1822 	 * Check if we need to delay processing because of ALUA
1823 	 * Active/NonOptimized primary access state..
1824 	 */
1825 	core_alua_check_nonop_delay(se_cmd);
1826 
1827 	transport_handle_cdb_direct(se_cmd);
1828 }
1829 EXPORT_SYMBOL_GPL(target_submit);
1830 
1831 /**
1832  * target_submit_cmd - lookup unpacked lun and submit uninitialized se_cmd
1833  *
1834  * @se_cmd: command descriptor to submit
1835  * @se_sess: associated se_sess for endpoint
1836  * @cdb: pointer to SCSI CDB
1837  * @sense: pointer to SCSI sense buffer
1838  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1839  * @data_length: fabric expected data transfer length
1840  * @task_attr: SAM task attribute
1841  * @data_dir: DMA data direction
1842  * @flags: flags for command submission from target_sc_flags_tables
1843  *
1844  * Task tags are supported if the caller has set @se_cmd->tag.
1845  *
1846  * This may only be called from process context, and also currently
1847  * assumes internal allocation of fabric payload buffer by target-core.
1848  *
1849  * It also assumes interal target core SGL memory allocation.
1850  *
1851  * This function must only be used by drivers that do their own
1852  * sync during shutdown and does not use target_stop_session. If there
1853  * is a failure this function will call into the fabric driver's
1854  * queue_status with a CHECK_CONDITION.
1855  */
1856 void target_submit_cmd(struct se_cmd *se_cmd, struct se_session *se_sess,
1857 		unsigned char *cdb, unsigned char *sense, u64 unpacked_lun,
1858 		u32 data_length, int task_attr, int data_dir, int flags)
1859 {
1860 	int rc;
1861 
1862 	rc = target_init_cmd(se_cmd, se_sess, sense, unpacked_lun, data_length,
1863 			     task_attr, data_dir, flags);
1864 	WARN(rc, "Invalid target_submit_cmd use. Driver must not use target_stop_session or call target_init_cmd directly.\n");
1865 	if (rc)
1866 		return;
1867 
1868 	if (target_submit_prep(se_cmd, cdb, NULL, 0, NULL, 0, NULL, 0,
1869 			       GFP_KERNEL))
1870 		return;
1871 
1872 	target_submit(se_cmd);
1873 }
1874 EXPORT_SYMBOL(target_submit_cmd);
1875 
1876 
1877 static struct se_dev_plug *target_plug_device(struct se_device *se_dev)
1878 {
1879 	struct se_dev_plug *se_plug;
1880 
1881 	if (!se_dev->transport->plug_device)
1882 		return NULL;
1883 
1884 	se_plug = se_dev->transport->plug_device(se_dev);
1885 	if (!se_plug)
1886 		return NULL;
1887 
1888 	se_plug->se_dev = se_dev;
1889 	/*
1890 	 * We have a ref to the lun at this point, but the cmds could
1891 	 * complete before we unplug, so grab a ref to the se_device so we
1892 	 * can call back into the backend.
1893 	 */
1894 	config_group_get(&se_dev->dev_group);
1895 	return se_plug;
1896 }
1897 
1898 static void target_unplug_device(struct se_dev_plug *se_plug)
1899 {
1900 	struct se_device *se_dev = se_plug->se_dev;
1901 
1902 	se_dev->transport->unplug_device(se_plug);
1903 	config_group_put(&se_dev->dev_group);
1904 }
1905 
1906 void target_queued_submit_work(struct work_struct *work)
1907 {
1908 	struct se_cmd_queue *sq = container_of(work, struct se_cmd_queue, work);
1909 	struct se_cmd *se_cmd, *next_cmd;
1910 	struct se_dev_plug *se_plug = NULL;
1911 	struct se_device *se_dev = NULL;
1912 	struct llist_node *cmd_list;
1913 
1914 	cmd_list = llist_del_all(&sq->cmd_list);
1915 	if (!cmd_list)
1916 		/* Previous call took what we were queued to submit */
1917 		return;
1918 
1919 	cmd_list = llist_reverse_order(cmd_list);
1920 	llist_for_each_entry_safe(se_cmd, next_cmd, cmd_list, se_cmd_list) {
1921 		if (!se_dev) {
1922 			se_dev = se_cmd->se_dev;
1923 			se_plug = target_plug_device(se_dev);
1924 		}
1925 
1926 		target_submit(se_cmd);
1927 	}
1928 
1929 	if (se_plug)
1930 		target_unplug_device(se_plug);
1931 }
1932 
1933 /**
1934  * target_queue_submission - queue the cmd to run on the LIO workqueue
1935  * @se_cmd: command descriptor to submit
1936  */
1937 void target_queue_submission(struct se_cmd *se_cmd)
1938 {
1939 	struct se_device *se_dev = se_cmd->se_dev;
1940 	int cpu = se_cmd->cpuid;
1941 	struct se_cmd_queue *sq;
1942 
1943 	sq = &se_dev->queues[cpu].sq;
1944 	llist_add(&se_cmd->se_cmd_list, &sq->cmd_list);
1945 	queue_work_on(cpu, target_submission_wq, &sq->work);
1946 }
1947 EXPORT_SYMBOL_GPL(target_queue_submission);
1948 
1949 static void target_complete_tmr_failure(struct work_struct *work)
1950 {
1951 	struct se_cmd *se_cmd = container_of(work, struct se_cmd, work);
1952 
1953 	se_cmd->se_tmr_req->response = TMR_LUN_DOES_NOT_EXIST;
1954 	se_cmd->se_tfo->queue_tm_rsp(se_cmd);
1955 
1956 	transport_lun_remove_cmd(se_cmd);
1957 	transport_cmd_check_stop_to_fabric(se_cmd);
1958 }
1959 
1960 /**
1961  * target_submit_tmr - lookup unpacked lun and submit uninitialized se_cmd
1962  *                     for TMR CDBs
1963  *
1964  * @se_cmd: command descriptor to submit
1965  * @se_sess: associated se_sess for endpoint
1966  * @sense: pointer to SCSI sense buffer
1967  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1968  * @fabric_tmr_ptr: fabric context for TMR req
1969  * @tm_type: Type of TM request
1970  * @gfp: gfp type for caller
1971  * @tag: referenced task tag for TMR_ABORT_TASK
1972  * @flags: submit cmd flags
1973  *
1974  * Callable from all contexts.
1975  **/
1976 
1977 int target_submit_tmr(struct se_cmd *se_cmd, struct se_session *se_sess,
1978 		unsigned char *sense, u64 unpacked_lun,
1979 		void *fabric_tmr_ptr, unsigned char tm_type,
1980 		gfp_t gfp, u64 tag, int flags)
1981 {
1982 	struct se_portal_group *se_tpg;
1983 	int ret;
1984 
1985 	se_tpg = se_sess->se_tpg;
1986 	BUG_ON(!se_tpg);
1987 
1988 	__target_init_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess,
1989 			  0, DMA_NONE, TCM_SIMPLE_TAG, sense, unpacked_lun,
1990 			  se_sess->cmd_cnt);
1991 	/*
1992 	 * FIXME: Currently expect caller to handle se_cmd->se_tmr_req
1993 	 * allocation failure.
1994 	 */
1995 	ret = core_tmr_alloc_req(se_cmd, fabric_tmr_ptr, tm_type, gfp);
1996 	if (ret < 0)
1997 		return -ENOMEM;
1998 
1999 	if (tm_type == TMR_ABORT_TASK)
2000 		se_cmd->se_tmr_req->ref_task_tag = tag;
2001 
2002 	/* See target_submit_cmd for commentary */
2003 	ret = target_get_sess_cmd(se_cmd, flags & TARGET_SCF_ACK_KREF);
2004 	if (ret) {
2005 		core_tmr_release_req(se_cmd->se_tmr_req);
2006 		return ret;
2007 	}
2008 
2009 	ret = transport_lookup_tmr_lun(se_cmd);
2010 	if (ret)
2011 		goto failure;
2012 
2013 	transport_generic_handle_tmr(se_cmd);
2014 	return 0;
2015 
2016 	/*
2017 	 * For callback during failure handling, push this work off
2018 	 * to process context with TMR_LUN_DOES_NOT_EXIST status.
2019 	 */
2020 failure:
2021 	INIT_WORK(&se_cmd->work, target_complete_tmr_failure);
2022 	schedule_work(&se_cmd->work);
2023 	return 0;
2024 }
2025 EXPORT_SYMBOL(target_submit_tmr);
2026 
2027 /*
2028  * Handle SAM-esque emulation for generic transport request failures.
2029  */
2030 void transport_generic_request_failure(struct se_cmd *cmd,
2031 		sense_reason_t sense_reason)
2032 {
2033 	int ret = 0, post_ret;
2034 
2035 	pr_debug("-----[ Storage Engine Exception; sense_reason %d\n",
2036 		 sense_reason);
2037 	target_show_cmd("-----[ ", cmd);
2038 
2039 	/*
2040 	 * For SAM Task Attribute emulation for failed struct se_cmd
2041 	 */
2042 	transport_complete_task_attr(cmd);
2043 
2044 	if (cmd->transport_complete_callback)
2045 		cmd->transport_complete_callback(cmd, false, &post_ret);
2046 
2047 	if (cmd->transport_state & CMD_T_ABORTED) {
2048 		INIT_WORK(&cmd->work, target_abort_work);
2049 		queue_work(target_completion_wq, &cmd->work);
2050 		return;
2051 	}
2052 
2053 	switch (sense_reason) {
2054 	case TCM_NON_EXISTENT_LUN:
2055 	case TCM_UNSUPPORTED_SCSI_OPCODE:
2056 	case TCM_INVALID_CDB_FIELD:
2057 	case TCM_INVALID_PARAMETER_LIST:
2058 	case TCM_PARAMETER_LIST_LENGTH_ERROR:
2059 	case TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE:
2060 	case TCM_UNKNOWN_MODE_PAGE:
2061 	case TCM_WRITE_PROTECTED:
2062 	case TCM_ADDRESS_OUT_OF_RANGE:
2063 	case TCM_CHECK_CONDITION_ABORT_CMD:
2064 	case TCM_CHECK_CONDITION_UNIT_ATTENTION:
2065 	case TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED:
2066 	case TCM_LOGICAL_BLOCK_APP_TAG_CHECK_FAILED:
2067 	case TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED:
2068 	case TCM_COPY_TARGET_DEVICE_NOT_REACHABLE:
2069 	case TCM_TOO_MANY_TARGET_DESCS:
2070 	case TCM_UNSUPPORTED_TARGET_DESC_TYPE_CODE:
2071 	case TCM_TOO_MANY_SEGMENT_DESCS:
2072 	case TCM_UNSUPPORTED_SEGMENT_DESC_TYPE_CODE:
2073 	case TCM_INVALID_FIELD_IN_COMMAND_IU:
2074 	case TCM_ALUA_TG_PT_STANDBY:
2075 	case TCM_ALUA_TG_PT_UNAVAILABLE:
2076 	case TCM_ALUA_STATE_TRANSITION:
2077 	case TCM_ALUA_OFFLINE:
2078 		break;
2079 	case TCM_OUT_OF_RESOURCES:
2080 		cmd->scsi_status = SAM_STAT_TASK_SET_FULL;
2081 		goto queue_status;
2082 	case TCM_LUN_BUSY:
2083 		cmd->scsi_status = SAM_STAT_BUSY;
2084 		goto queue_status;
2085 	case TCM_RESERVATION_CONFLICT:
2086 		/*
2087 		 * No SENSE Data payload for this case, set SCSI Status
2088 		 * and queue the response to $FABRIC_MOD.
2089 		 *
2090 		 * Uses linux/include/scsi/scsi.h SAM status codes defs
2091 		 */
2092 		cmd->scsi_status = SAM_STAT_RESERVATION_CONFLICT;
2093 		/*
2094 		 * For UA Interlock Code 11b, a RESERVATION CONFLICT will
2095 		 * establish a UNIT ATTENTION with PREVIOUS RESERVATION
2096 		 * CONFLICT STATUS.
2097 		 *
2098 		 * See spc4r17, section 7.4.6 Control Mode Page, Table 349
2099 		 */
2100 		if (cmd->se_sess &&
2101 		    cmd->se_dev->dev_attrib.emulate_ua_intlck_ctrl
2102 					== TARGET_UA_INTLCK_CTRL_ESTABLISH_UA) {
2103 			target_ua_allocate_lun(cmd->se_sess->se_node_acl,
2104 					       cmd->orig_fe_lun, 0x2C,
2105 					ASCQ_2CH_PREVIOUS_RESERVATION_CONFLICT_STATUS);
2106 		}
2107 
2108 		goto queue_status;
2109 	default:
2110 		pr_err("Unknown transport error for CDB 0x%02x: %d\n",
2111 			cmd->t_task_cdb[0], sense_reason);
2112 		sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
2113 		break;
2114 	}
2115 
2116 	ret = transport_send_check_condition_and_sense(cmd, sense_reason, 0);
2117 	if (ret)
2118 		goto queue_full;
2119 
2120 check_stop:
2121 	transport_lun_remove_cmd(cmd);
2122 	transport_cmd_check_stop_to_fabric(cmd);
2123 	return;
2124 
2125 queue_status:
2126 	trace_target_cmd_complete(cmd);
2127 	ret = cmd->se_tfo->queue_status(cmd);
2128 	if (!ret)
2129 		goto check_stop;
2130 queue_full:
2131 	transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
2132 }
2133 EXPORT_SYMBOL(transport_generic_request_failure);
2134 
2135 void __target_execute_cmd(struct se_cmd *cmd, bool do_checks)
2136 {
2137 	sense_reason_t ret;
2138 
2139 	if (!cmd->execute_cmd) {
2140 		ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2141 		goto err;
2142 	}
2143 	if (do_checks) {
2144 		/*
2145 		 * Check for an existing UNIT ATTENTION condition after
2146 		 * target_handle_task_attr() has done SAM task attr
2147 		 * checking, and possibly have already defered execution
2148 		 * out to target_restart_delayed_cmds() context.
2149 		 */
2150 		ret = target_scsi3_ua_check(cmd);
2151 		if (ret)
2152 			goto err;
2153 
2154 		ret = target_alua_state_check(cmd);
2155 		if (ret)
2156 			goto err;
2157 
2158 		ret = target_check_reservation(cmd);
2159 		if (ret) {
2160 			cmd->scsi_status = SAM_STAT_RESERVATION_CONFLICT;
2161 			goto err;
2162 		}
2163 	}
2164 
2165 	ret = cmd->execute_cmd(cmd);
2166 	if (!ret)
2167 		return;
2168 err:
2169 	spin_lock_irq(&cmd->t_state_lock);
2170 	cmd->transport_state &= ~CMD_T_SENT;
2171 	spin_unlock_irq(&cmd->t_state_lock);
2172 
2173 	transport_generic_request_failure(cmd, ret);
2174 }
2175 
2176 static int target_write_prot_action(struct se_cmd *cmd)
2177 {
2178 	u32 sectors;
2179 	/*
2180 	 * Perform WRITE_INSERT of PI using software emulation when backend
2181 	 * device has PI enabled, if the transport has not already generated
2182 	 * PI using hardware WRITE_INSERT offload.
2183 	 */
2184 	switch (cmd->prot_op) {
2185 	case TARGET_PROT_DOUT_INSERT:
2186 		if (!(cmd->se_sess->sup_prot_ops & TARGET_PROT_DOUT_INSERT))
2187 			sbc_dif_generate(cmd);
2188 		break;
2189 	case TARGET_PROT_DOUT_STRIP:
2190 		if (cmd->se_sess->sup_prot_ops & TARGET_PROT_DOUT_STRIP)
2191 			break;
2192 
2193 		sectors = cmd->data_length >> ilog2(cmd->se_dev->dev_attrib.block_size);
2194 		cmd->pi_err = sbc_dif_verify(cmd, cmd->t_task_lba,
2195 					     sectors, 0, cmd->t_prot_sg, 0);
2196 		if (unlikely(cmd->pi_err)) {
2197 			spin_lock_irq(&cmd->t_state_lock);
2198 			cmd->transport_state &= ~CMD_T_SENT;
2199 			spin_unlock_irq(&cmd->t_state_lock);
2200 			transport_generic_request_failure(cmd, cmd->pi_err);
2201 			return -1;
2202 		}
2203 		break;
2204 	default:
2205 		break;
2206 	}
2207 
2208 	return 0;
2209 }
2210 
2211 static bool target_handle_task_attr(struct se_cmd *cmd)
2212 {
2213 	struct se_device *dev = cmd->se_dev;
2214 
2215 	if (dev->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
2216 		return false;
2217 
2218 	cmd->se_cmd_flags |= SCF_TASK_ATTR_SET;
2219 
2220 	/*
2221 	 * Check for the existence of HEAD_OF_QUEUE, and if true return 1
2222 	 * to allow the passed struct se_cmd list of tasks to the front of the list.
2223 	 */
2224 	switch (cmd->sam_task_attr) {
2225 	case TCM_HEAD_TAG:
2226 		atomic_inc_mb(&dev->non_ordered);
2227 		pr_debug("Added HEAD_OF_QUEUE for CDB: 0x%02x\n",
2228 			 cmd->t_task_cdb[0]);
2229 		return false;
2230 	case TCM_ORDERED_TAG:
2231 		atomic_inc_mb(&dev->delayed_cmd_count);
2232 
2233 		pr_debug("Added ORDERED for CDB: 0x%02x to ordered list\n",
2234 			 cmd->t_task_cdb[0]);
2235 		break;
2236 	default:
2237 		/*
2238 		 * For SIMPLE and UNTAGGED Task Attribute commands
2239 		 */
2240 		atomic_inc_mb(&dev->non_ordered);
2241 
2242 		if (atomic_read(&dev->delayed_cmd_count) == 0)
2243 			return false;
2244 		break;
2245 	}
2246 
2247 	if (cmd->sam_task_attr != TCM_ORDERED_TAG) {
2248 		atomic_inc_mb(&dev->delayed_cmd_count);
2249 		/*
2250 		 * We will account for this when we dequeue from the delayed
2251 		 * list.
2252 		 */
2253 		atomic_dec_mb(&dev->non_ordered);
2254 	}
2255 
2256 	spin_lock_irq(&cmd->t_state_lock);
2257 	cmd->transport_state &= ~CMD_T_SENT;
2258 	spin_unlock_irq(&cmd->t_state_lock);
2259 
2260 	spin_lock(&dev->delayed_cmd_lock);
2261 	list_add_tail(&cmd->se_delayed_node, &dev->delayed_cmd_list);
2262 	spin_unlock(&dev->delayed_cmd_lock);
2263 
2264 	pr_debug("Added CDB: 0x%02x Task Attr: 0x%02x to delayed CMD listn",
2265 		cmd->t_task_cdb[0], cmd->sam_task_attr);
2266 	/*
2267 	 * We may have no non ordered cmds when this function started or we
2268 	 * could have raced with the last simple/head cmd completing, so kick
2269 	 * the delayed handler here.
2270 	 */
2271 	schedule_work(&dev->delayed_cmd_work);
2272 	return true;
2273 }
2274 
2275 void target_execute_cmd(struct se_cmd *cmd)
2276 {
2277 	/*
2278 	 * Determine if frontend context caller is requesting the stopping of
2279 	 * this command for frontend exceptions.
2280 	 *
2281 	 * If the received CDB has already been aborted stop processing it here.
2282 	 */
2283 	if (target_cmd_interrupted(cmd))
2284 		return;
2285 
2286 	spin_lock_irq(&cmd->t_state_lock);
2287 	cmd->t_state = TRANSPORT_PROCESSING;
2288 	cmd->transport_state |= CMD_T_ACTIVE | CMD_T_SENT;
2289 	spin_unlock_irq(&cmd->t_state_lock);
2290 
2291 	if (target_write_prot_action(cmd))
2292 		return;
2293 
2294 	if (target_handle_task_attr(cmd))
2295 		return;
2296 
2297 	__target_execute_cmd(cmd, true);
2298 }
2299 EXPORT_SYMBOL(target_execute_cmd);
2300 
2301 /*
2302  * Process all commands up to the last received ORDERED task attribute which
2303  * requires another blocking boundary
2304  */
2305 void target_do_delayed_work(struct work_struct *work)
2306 {
2307 	struct se_device *dev = container_of(work, struct se_device,
2308 					     delayed_cmd_work);
2309 
2310 	spin_lock(&dev->delayed_cmd_lock);
2311 	while (!dev->ordered_sync_in_progress) {
2312 		struct se_cmd *cmd;
2313 
2314 		if (list_empty(&dev->delayed_cmd_list))
2315 			break;
2316 
2317 		cmd = list_entry(dev->delayed_cmd_list.next,
2318 				 struct se_cmd, se_delayed_node);
2319 
2320 		if (cmd->sam_task_attr == TCM_ORDERED_TAG) {
2321 			/*
2322 			 * Check if we started with:
2323 			 * [ordered] [simple] [ordered]
2324 			 * and we are now at the last ordered so we have to wait
2325 			 * for the simple cmd.
2326 			 */
2327 			if (atomic_read(&dev->non_ordered) > 0)
2328 				break;
2329 
2330 			dev->ordered_sync_in_progress = true;
2331 		}
2332 
2333 		list_del(&cmd->se_delayed_node);
2334 		atomic_dec_mb(&dev->delayed_cmd_count);
2335 		spin_unlock(&dev->delayed_cmd_lock);
2336 
2337 		if (cmd->sam_task_attr != TCM_ORDERED_TAG)
2338 			atomic_inc_mb(&dev->non_ordered);
2339 
2340 		cmd->transport_state |= CMD_T_SENT;
2341 
2342 		__target_execute_cmd(cmd, true);
2343 
2344 		spin_lock(&dev->delayed_cmd_lock);
2345 	}
2346 	spin_unlock(&dev->delayed_cmd_lock);
2347 }
2348 
2349 /*
2350  * Called from I/O completion to determine which dormant/delayed
2351  * and ordered cmds need to have their tasks added to the execution queue.
2352  */
2353 static void transport_complete_task_attr(struct se_cmd *cmd)
2354 {
2355 	struct se_device *dev = cmd->se_dev;
2356 
2357 	if (dev->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
2358 		return;
2359 
2360 	if (!(cmd->se_cmd_flags & SCF_TASK_ATTR_SET))
2361 		goto restart;
2362 
2363 	if (cmd->sam_task_attr == TCM_SIMPLE_TAG) {
2364 		atomic_dec_mb(&dev->non_ordered);
2365 		dev->dev_cur_ordered_id++;
2366 	} else if (cmd->sam_task_attr == TCM_HEAD_TAG) {
2367 		atomic_dec_mb(&dev->non_ordered);
2368 		dev->dev_cur_ordered_id++;
2369 		pr_debug("Incremented dev_cur_ordered_id: %u for HEAD_OF_QUEUE\n",
2370 			 dev->dev_cur_ordered_id);
2371 	} else if (cmd->sam_task_attr == TCM_ORDERED_TAG) {
2372 		spin_lock(&dev->delayed_cmd_lock);
2373 		dev->ordered_sync_in_progress = false;
2374 		spin_unlock(&dev->delayed_cmd_lock);
2375 
2376 		dev->dev_cur_ordered_id++;
2377 		pr_debug("Incremented dev_cur_ordered_id: %u for ORDERED\n",
2378 			 dev->dev_cur_ordered_id);
2379 	}
2380 	cmd->se_cmd_flags &= ~SCF_TASK_ATTR_SET;
2381 
2382 restart:
2383 	if (atomic_read(&dev->delayed_cmd_count) > 0)
2384 		schedule_work(&dev->delayed_cmd_work);
2385 }
2386 
2387 static void transport_complete_qf(struct se_cmd *cmd)
2388 {
2389 	int ret = 0;
2390 
2391 	transport_complete_task_attr(cmd);
2392 	/*
2393 	 * If a fabric driver ->write_pending() or ->queue_data_in() callback
2394 	 * has returned neither -ENOMEM or -EAGAIN, assume it's fatal and
2395 	 * the same callbacks should not be retried.  Return CHECK_CONDITION
2396 	 * if a scsi_status is not already set.
2397 	 *
2398 	 * If a fabric driver ->queue_status() has returned non zero, always
2399 	 * keep retrying no matter what..
2400 	 */
2401 	if (cmd->t_state == TRANSPORT_COMPLETE_QF_ERR) {
2402 		if (cmd->scsi_status)
2403 			goto queue_status;
2404 
2405 		translate_sense_reason(cmd, TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE);
2406 		goto queue_status;
2407 	}
2408 
2409 	/*
2410 	 * Check if we need to send a sense buffer from
2411 	 * the struct se_cmd in question. We do NOT want
2412 	 * to take this path of the IO has been marked as
2413 	 * needing to be treated like a "normal read". This
2414 	 * is the case if it's a tape read, and either the
2415 	 * FM, EOM, or ILI bits are set, but there is no
2416 	 * sense data.
2417 	 */
2418 	if (!(cmd->se_cmd_flags & SCF_TREAT_READ_AS_NORMAL) &&
2419 	    cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE)
2420 		goto queue_status;
2421 
2422 	switch (cmd->data_direction) {
2423 	case DMA_FROM_DEVICE:
2424 		/* queue status if not treating this as a normal read */
2425 		if (cmd->scsi_status &&
2426 		    !(cmd->se_cmd_flags & SCF_TREAT_READ_AS_NORMAL))
2427 			goto queue_status;
2428 
2429 		trace_target_cmd_complete(cmd);
2430 		ret = cmd->se_tfo->queue_data_in(cmd);
2431 		break;
2432 	case DMA_TO_DEVICE:
2433 		if (cmd->se_cmd_flags & SCF_BIDI) {
2434 			ret = cmd->se_tfo->queue_data_in(cmd);
2435 			break;
2436 		}
2437 		fallthrough;
2438 	case DMA_NONE:
2439 queue_status:
2440 		trace_target_cmd_complete(cmd);
2441 		ret = cmd->se_tfo->queue_status(cmd);
2442 		break;
2443 	default:
2444 		break;
2445 	}
2446 
2447 	if (ret < 0) {
2448 		transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
2449 		return;
2450 	}
2451 	transport_lun_remove_cmd(cmd);
2452 	transport_cmd_check_stop_to_fabric(cmd);
2453 }
2454 
2455 static void transport_handle_queue_full(struct se_cmd *cmd, struct se_device *dev,
2456 					int err, bool write_pending)
2457 {
2458 	/*
2459 	 * -EAGAIN or -ENOMEM signals retry of ->write_pending() and/or
2460 	 * ->queue_data_in() callbacks from new process context.
2461 	 *
2462 	 * Otherwise for other errors, transport_complete_qf() will send
2463 	 * CHECK_CONDITION via ->queue_status() instead of attempting to
2464 	 * retry associated fabric driver data-transfer callbacks.
2465 	 */
2466 	if (err == -EAGAIN || err == -ENOMEM) {
2467 		cmd->t_state = (write_pending) ? TRANSPORT_COMPLETE_QF_WP :
2468 						 TRANSPORT_COMPLETE_QF_OK;
2469 	} else {
2470 		pr_warn_ratelimited("Got unknown fabric queue status: %d\n", err);
2471 		cmd->t_state = TRANSPORT_COMPLETE_QF_ERR;
2472 	}
2473 
2474 	spin_lock_irq(&dev->qf_cmd_lock);
2475 	list_add_tail(&cmd->se_qf_node, &cmd->se_dev->qf_cmd_list);
2476 	atomic_inc_mb(&dev->dev_qf_count);
2477 	spin_unlock_irq(&cmd->se_dev->qf_cmd_lock);
2478 
2479 	schedule_work(&cmd->se_dev->qf_work_queue);
2480 }
2481 
2482 static bool target_read_prot_action(struct se_cmd *cmd)
2483 {
2484 	switch (cmd->prot_op) {
2485 	case TARGET_PROT_DIN_STRIP:
2486 		if (!(cmd->se_sess->sup_prot_ops & TARGET_PROT_DIN_STRIP)) {
2487 			u32 sectors = cmd->data_length >>
2488 				  ilog2(cmd->se_dev->dev_attrib.block_size);
2489 
2490 			cmd->pi_err = sbc_dif_verify(cmd, cmd->t_task_lba,
2491 						     sectors, 0, cmd->t_prot_sg,
2492 						     0);
2493 			if (cmd->pi_err)
2494 				return true;
2495 		}
2496 		break;
2497 	case TARGET_PROT_DIN_INSERT:
2498 		if (cmd->se_sess->sup_prot_ops & TARGET_PROT_DIN_INSERT)
2499 			break;
2500 
2501 		sbc_dif_generate(cmd);
2502 		break;
2503 	default:
2504 		break;
2505 	}
2506 
2507 	return false;
2508 }
2509 
2510 static void target_complete_ok_work(struct work_struct *work)
2511 {
2512 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
2513 	int ret;
2514 
2515 	/*
2516 	 * Check if we need to move delayed/dormant tasks from cmds on the
2517 	 * delayed execution list after a HEAD_OF_QUEUE or ORDERED Task
2518 	 * Attribute.
2519 	 */
2520 	transport_complete_task_attr(cmd);
2521 
2522 	/*
2523 	 * Check to schedule QUEUE_FULL work, or execute an existing
2524 	 * cmd->transport_qf_callback()
2525 	 */
2526 	if (atomic_read(&cmd->se_dev->dev_qf_count) != 0)
2527 		schedule_work(&cmd->se_dev->qf_work_queue);
2528 
2529 	/*
2530 	 * Check if we need to send a sense buffer from
2531 	 * the struct se_cmd in question. We do NOT want
2532 	 * to take this path of the IO has been marked as
2533 	 * needing to be treated like a "normal read". This
2534 	 * is the case if it's a tape read, and either the
2535 	 * FM, EOM, or ILI bits are set, but there is no
2536 	 * sense data.
2537 	 */
2538 	if (!(cmd->se_cmd_flags & SCF_TREAT_READ_AS_NORMAL) &&
2539 	    cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) {
2540 		WARN_ON(!cmd->scsi_status);
2541 		ret = transport_send_check_condition_and_sense(
2542 					cmd, 0, 1);
2543 		if (ret)
2544 			goto queue_full;
2545 
2546 		transport_lun_remove_cmd(cmd);
2547 		transport_cmd_check_stop_to_fabric(cmd);
2548 		return;
2549 	}
2550 	/*
2551 	 * Check for a callback, used by amongst other things
2552 	 * XDWRITE_READ_10 and COMPARE_AND_WRITE emulation.
2553 	 */
2554 	if (cmd->transport_complete_callback) {
2555 		sense_reason_t rc;
2556 		bool caw = (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE);
2557 		bool zero_dl = !(cmd->data_length);
2558 		int post_ret = 0;
2559 
2560 		rc = cmd->transport_complete_callback(cmd, true, &post_ret);
2561 		if (!rc && !post_ret) {
2562 			if (caw && zero_dl)
2563 				goto queue_rsp;
2564 
2565 			return;
2566 		} else if (rc) {
2567 			ret = transport_send_check_condition_and_sense(cmd,
2568 						rc, 0);
2569 			if (ret)
2570 				goto queue_full;
2571 
2572 			transport_lun_remove_cmd(cmd);
2573 			transport_cmd_check_stop_to_fabric(cmd);
2574 			return;
2575 		}
2576 	}
2577 
2578 queue_rsp:
2579 	switch (cmd->data_direction) {
2580 	case DMA_FROM_DEVICE:
2581 		/*
2582 		 * if this is a READ-type IO, but SCSI status
2583 		 * is set, then skip returning data and just
2584 		 * return the status -- unless this IO is marked
2585 		 * as needing to be treated as a normal read,
2586 		 * in which case we want to go ahead and return
2587 		 * the data. This happens, for example, for tape
2588 		 * reads with the FM, EOM, or ILI bits set, with
2589 		 * no sense data.
2590 		 */
2591 		if (cmd->scsi_status &&
2592 		    !(cmd->se_cmd_flags & SCF_TREAT_READ_AS_NORMAL))
2593 			goto queue_status;
2594 
2595 		atomic_long_add(cmd->data_length,
2596 				&cmd->se_lun->lun_stats.tx_data_octets);
2597 		/*
2598 		 * Perform READ_STRIP of PI using software emulation when
2599 		 * backend had PI enabled, if the transport will not be
2600 		 * performing hardware READ_STRIP offload.
2601 		 */
2602 		if (target_read_prot_action(cmd)) {
2603 			ret = transport_send_check_condition_and_sense(cmd,
2604 						cmd->pi_err, 0);
2605 			if (ret)
2606 				goto queue_full;
2607 
2608 			transport_lun_remove_cmd(cmd);
2609 			transport_cmd_check_stop_to_fabric(cmd);
2610 			return;
2611 		}
2612 
2613 		trace_target_cmd_complete(cmd);
2614 		ret = cmd->se_tfo->queue_data_in(cmd);
2615 		if (ret)
2616 			goto queue_full;
2617 		break;
2618 	case DMA_TO_DEVICE:
2619 		atomic_long_add(cmd->data_length,
2620 				&cmd->se_lun->lun_stats.rx_data_octets);
2621 		/*
2622 		 * Check if we need to send READ payload for BIDI-COMMAND
2623 		 */
2624 		if (cmd->se_cmd_flags & SCF_BIDI) {
2625 			atomic_long_add(cmd->data_length,
2626 					&cmd->se_lun->lun_stats.tx_data_octets);
2627 			ret = cmd->se_tfo->queue_data_in(cmd);
2628 			if (ret)
2629 				goto queue_full;
2630 			break;
2631 		}
2632 		fallthrough;
2633 	case DMA_NONE:
2634 queue_status:
2635 		trace_target_cmd_complete(cmd);
2636 		ret = cmd->se_tfo->queue_status(cmd);
2637 		if (ret)
2638 			goto queue_full;
2639 		break;
2640 	default:
2641 		break;
2642 	}
2643 
2644 	transport_lun_remove_cmd(cmd);
2645 	transport_cmd_check_stop_to_fabric(cmd);
2646 	return;
2647 
2648 queue_full:
2649 	pr_debug("Handling complete_ok QUEUE_FULL: se_cmd: %p,"
2650 		" data_direction: %d\n", cmd, cmd->data_direction);
2651 
2652 	transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
2653 }
2654 
2655 void target_free_sgl(struct scatterlist *sgl, int nents)
2656 {
2657 	sgl_free_n_order(sgl, nents, 0);
2658 }
2659 EXPORT_SYMBOL(target_free_sgl);
2660 
2661 static inline void transport_reset_sgl_orig(struct se_cmd *cmd)
2662 {
2663 	/*
2664 	 * Check for saved t_data_sg that may be used for COMPARE_AND_WRITE
2665 	 * emulation, and free + reset pointers if necessary..
2666 	 */
2667 	if (!cmd->t_data_sg_orig)
2668 		return;
2669 
2670 	kfree(cmd->t_data_sg);
2671 	cmd->t_data_sg = cmd->t_data_sg_orig;
2672 	cmd->t_data_sg_orig = NULL;
2673 	cmd->t_data_nents = cmd->t_data_nents_orig;
2674 	cmd->t_data_nents_orig = 0;
2675 }
2676 
2677 static inline void transport_free_pages(struct se_cmd *cmd)
2678 {
2679 	if (!(cmd->se_cmd_flags & SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC)) {
2680 		target_free_sgl(cmd->t_prot_sg, cmd->t_prot_nents);
2681 		cmd->t_prot_sg = NULL;
2682 		cmd->t_prot_nents = 0;
2683 	}
2684 
2685 	if (cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) {
2686 		/*
2687 		 * Release special case READ buffer payload required for
2688 		 * SG_TO_MEM_NOALLOC to function with COMPARE_AND_WRITE
2689 		 */
2690 		if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) {
2691 			target_free_sgl(cmd->t_bidi_data_sg,
2692 					   cmd->t_bidi_data_nents);
2693 			cmd->t_bidi_data_sg = NULL;
2694 			cmd->t_bidi_data_nents = 0;
2695 		}
2696 		transport_reset_sgl_orig(cmd);
2697 		return;
2698 	}
2699 	transport_reset_sgl_orig(cmd);
2700 
2701 	target_free_sgl(cmd->t_data_sg, cmd->t_data_nents);
2702 	cmd->t_data_sg = NULL;
2703 	cmd->t_data_nents = 0;
2704 
2705 	target_free_sgl(cmd->t_bidi_data_sg, cmd->t_bidi_data_nents);
2706 	cmd->t_bidi_data_sg = NULL;
2707 	cmd->t_bidi_data_nents = 0;
2708 }
2709 
2710 void *transport_kmap_data_sg(struct se_cmd *cmd)
2711 {
2712 	struct scatterlist *sg = cmd->t_data_sg;
2713 	struct page **pages;
2714 	int i;
2715 
2716 	/*
2717 	 * We need to take into account a possible offset here for fabrics like
2718 	 * tcm_loop who may be using a contig buffer from the SCSI midlayer for
2719 	 * control CDBs passed as SGLs via transport_generic_map_mem_to_cmd()
2720 	 */
2721 	if (!cmd->t_data_nents)
2722 		return NULL;
2723 
2724 	BUG_ON(!sg);
2725 	if (cmd->t_data_nents == 1)
2726 		return kmap(sg_page(sg)) + sg->offset;
2727 
2728 	/* >1 page. use vmap */
2729 	pages = kmalloc_array(cmd->t_data_nents, sizeof(*pages), GFP_KERNEL);
2730 	if (!pages)
2731 		return NULL;
2732 
2733 	/* convert sg[] to pages[] */
2734 	for_each_sg(cmd->t_data_sg, sg, cmd->t_data_nents, i) {
2735 		pages[i] = sg_page(sg);
2736 	}
2737 
2738 	cmd->t_data_vmap = vmap(pages, cmd->t_data_nents,  VM_MAP, PAGE_KERNEL);
2739 	kfree(pages);
2740 	if (!cmd->t_data_vmap)
2741 		return NULL;
2742 
2743 	return cmd->t_data_vmap + cmd->t_data_sg[0].offset;
2744 }
2745 EXPORT_SYMBOL(transport_kmap_data_sg);
2746 
2747 void transport_kunmap_data_sg(struct se_cmd *cmd)
2748 {
2749 	if (!cmd->t_data_nents) {
2750 		return;
2751 	} else if (cmd->t_data_nents == 1) {
2752 		kunmap(sg_page(cmd->t_data_sg));
2753 		return;
2754 	}
2755 
2756 	vunmap(cmd->t_data_vmap);
2757 	cmd->t_data_vmap = NULL;
2758 }
2759 EXPORT_SYMBOL(transport_kunmap_data_sg);
2760 
2761 int
2762 target_alloc_sgl(struct scatterlist **sgl, unsigned int *nents, u32 length,
2763 		 bool zero_page, bool chainable)
2764 {
2765 	gfp_t gfp = GFP_KERNEL | (zero_page ? __GFP_ZERO : 0);
2766 
2767 	*sgl = sgl_alloc_order(length, 0, chainable, gfp, nents);
2768 	return *sgl ? 0 : -ENOMEM;
2769 }
2770 EXPORT_SYMBOL(target_alloc_sgl);
2771 
2772 /*
2773  * Allocate any required resources to execute the command.  For writes we
2774  * might not have the payload yet, so notify the fabric via a call to
2775  * ->write_pending instead. Otherwise place it on the execution queue.
2776  */
2777 sense_reason_t
2778 transport_generic_new_cmd(struct se_cmd *cmd)
2779 {
2780 	unsigned long flags;
2781 	int ret = 0;
2782 	bool zero_flag = !(cmd->se_cmd_flags & SCF_SCSI_DATA_CDB);
2783 
2784 	if (cmd->prot_op != TARGET_PROT_NORMAL &&
2785 	    !(cmd->se_cmd_flags & SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC)) {
2786 		ret = target_alloc_sgl(&cmd->t_prot_sg, &cmd->t_prot_nents,
2787 				       cmd->prot_length, true, false);
2788 		if (ret < 0)
2789 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2790 	}
2791 
2792 	/*
2793 	 * Determine if the TCM fabric module has already allocated physical
2794 	 * memory, and is directly calling transport_generic_map_mem_to_cmd()
2795 	 * beforehand.
2796 	 */
2797 	if (!(cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) &&
2798 	    cmd->data_length) {
2799 
2800 		if ((cmd->se_cmd_flags & SCF_BIDI) ||
2801 		    (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE)) {
2802 			u32 bidi_length;
2803 
2804 			if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE)
2805 				bidi_length = cmd->t_task_nolb *
2806 					      cmd->se_dev->dev_attrib.block_size;
2807 			else
2808 				bidi_length = cmd->data_length;
2809 
2810 			ret = target_alloc_sgl(&cmd->t_bidi_data_sg,
2811 					       &cmd->t_bidi_data_nents,
2812 					       bidi_length, zero_flag, false);
2813 			if (ret < 0)
2814 				return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2815 		}
2816 
2817 		ret = target_alloc_sgl(&cmd->t_data_sg, &cmd->t_data_nents,
2818 				       cmd->data_length, zero_flag, false);
2819 		if (ret < 0)
2820 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2821 	} else if ((cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) &&
2822 		    cmd->data_length) {
2823 		/*
2824 		 * Special case for COMPARE_AND_WRITE with fabrics
2825 		 * using SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC.
2826 		 */
2827 		u32 caw_length = cmd->t_task_nolb *
2828 				 cmd->se_dev->dev_attrib.block_size;
2829 
2830 		ret = target_alloc_sgl(&cmd->t_bidi_data_sg,
2831 				       &cmd->t_bidi_data_nents,
2832 				       caw_length, zero_flag, false);
2833 		if (ret < 0)
2834 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2835 	}
2836 	/*
2837 	 * If this command is not a write we can execute it right here,
2838 	 * for write buffers we need to notify the fabric driver first
2839 	 * and let it call back once the write buffers are ready.
2840 	 */
2841 	target_add_to_state_list(cmd);
2842 	if (cmd->data_direction != DMA_TO_DEVICE || cmd->data_length == 0) {
2843 		target_execute_cmd(cmd);
2844 		return 0;
2845 	}
2846 
2847 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2848 	cmd->t_state = TRANSPORT_WRITE_PENDING;
2849 	/*
2850 	 * Determine if frontend context caller is requesting the stopping of
2851 	 * this command for frontend exceptions.
2852 	 */
2853 	if (cmd->transport_state & CMD_T_STOP &&
2854 	    !cmd->se_tfo->write_pending_must_be_called) {
2855 		pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08llx\n",
2856 			 __func__, __LINE__, cmd->tag);
2857 
2858 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2859 
2860 		complete_all(&cmd->t_transport_stop_comp);
2861 		return 0;
2862 	}
2863 	cmd->transport_state &= ~CMD_T_ACTIVE;
2864 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2865 
2866 	ret = cmd->se_tfo->write_pending(cmd);
2867 	if (ret)
2868 		goto queue_full;
2869 
2870 	return 0;
2871 
2872 queue_full:
2873 	pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n", cmd);
2874 	transport_handle_queue_full(cmd, cmd->se_dev, ret, true);
2875 	return 0;
2876 }
2877 EXPORT_SYMBOL(transport_generic_new_cmd);
2878 
2879 static void transport_write_pending_qf(struct se_cmd *cmd)
2880 {
2881 	unsigned long flags;
2882 	int ret;
2883 	bool stop;
2884 
2885 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2886 	stop = (cmd->transport_state & (CMD_T_STOP | CMD_T_ABORTED));
2887 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2888 
2889 	if (stop) {
2890 		pr_debug("%s:%d CMD_T_STOP|CMD_T_ABORTED for ITT: 0x%08llx\n",
2891 			__func__, __LINE__, cmd->tag);
2892 		complete_all(&cmd->t_transport_stop_comp);
2893 		return;
2894 	}
2895 
2896 	ret = cmd->se_tfo->write_pending(cmd);
2897 	if (ret) {
2898 		pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n",
2899 			 cmd);
2900 		transport_handle_queue_full(cmd, cmd->se_dev, ret, true);
2901 	}
2902 }
2903 
2904 static bool
2905 __transport_wait_for_tasks(struct se_cmd *, bool, bool *, bool *,
2906 			   unsigned long *flags);
2907 
2908 static void target_wait_free_cmd(struct se_cmd *cmd, bool *aborted, bool *tas)
2909 {
2910 	unsigned long flags;
2911 
2912 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2913 	__transport_wait_for_tasks(cmd, true, aborted, tas, &flags);
2914 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2915 }
2916 
2917 /*
2918  * Call target_put_sess_cmd() and wait until target_release_cmd_kref(@cmd) has
2919  * finished.
2920  */
2921 void target_put_cmd_and_wait(struct se_cmd *cmd)
2922 {
2923 	DECLARE_COMPLETION_ONSTACK(compl);
2924 
2925 	WARN_ON_ONCE(cmd->abrt_compl);
2926 	cmd->abrt_compl = &compl;
2927 	target_put_sess_cmd(cmd);
2928 	wait_for_completion(&compl);
2929 }
2930 
2931 /*
2932  * This function is called by frontend drivers after processing of a command
2933  * has finished.
2934  *
2935  * The protocol for ensuring that either the regular frontend command
2936  * processing flow or target_handle_abort() code drops one reference is as
2937  * follows:
2938  * - Calling .queue_data_in(), .queue_status() or queue_tm_rsp() will cause
2939  *   the frontend driver to call this function synchronously or asynchronously.
2940  *   That will cause one reference to be dropped.
2941  * - During regular command processing the target core sets CMD_T_COMPLETE
2942  *   before invoking one of the .queue_*() functions.
2943  * - The code that aborts commands skips commands and TMFs for which
2944  *   CMD_T_COMPLETE has been set.
2945  * - CMD_T_ABORTED is set atomically after the CMD_T_COMPLETE check for
2946  *   commands that will be aborted.
2947  * - If the CMD_T_ABORTED flag is set but CMD_T_TAS has not been set
2948  *   transport_generic_free_cmd() skips its call to target_put_sess_cmd().
2949  * - For aborted commands for which CMD_T_TAS has been set .queue_status() will
2950  *   be called and will drop a reference.
2951  * - For aborted commands for which CMD_T_TAS has not been set .aborted_task()
2952  *   will be called. target_handle_abort() will drop the final reference.
2953  */
2954 int transport_generic_free_cmd(struct se_cmd *cmd, int wait_for_tasks)
2955 {
2956 	DECLARE_COMPLETION_ONSTACK(compl);
2957 	int ret = 0;
2958 	bool aborted = false, tas = false;
2959 
2960 	if (wait_for_tasks)
2961 		target_wait_free_cmd(cmd, &aborted, &tas);
2962 
2963 	if (cmd->se_cmd_flags & SCF_SE_LUN_CMD) {
2964 		/*
2965 		 * Handle WRITE failure case where transport_generic_new_cmd()
2966 		 * has already added se_cmd to state_list, but fabric has
2967 		 * failed command before I/O submission.
2968 		 */
2969 		if (cmd->state_active)
2970 			target_remove_from_state_list(cmd);
2971 
2972 		if (cmd->se_lun)
2973 			transport_lun_remove_cmd(cmd);
2974 	}
2975 	if (aborted)
2976 		cmd->free_compl = &compl;
2977 	ret = target_put_sess_cmd(cmd);
2978 	if (aborted) {
2979 		pr_debug("Detected CMD_T_ABORTED for ITT: %llu\n", cmd->tag);
2980 		wait_for_completion(&compl);
2981 		ret = 1;
2982 	}
2983 	return ret;
2984 }
2985 EXPORT_SYMBOL(transport_generic_free_cmd);
2986 
2987 /**
2988  * target_get_sess_cmd - Verify the session is accepting cmds and take ref
2989  * @se_cmd:	command descriptor to add
2990  * @ack_kref:	Signal that fabric will perform an ack target_put_sess_cmd()
2991  */
2992 int target_get_sess_cmd(struct se_cmd *se_cmd, bool ack_kref)
2993 {
2994 	int ret = 0;
2995 
2996 	/*
2997 	 * Add a second kref if the fabric caller is expecting to handle
2998 	 * fabric acknowledgement that requires two target_put_sess_cmd()
2999 	 * invocations before se_cmd descriptor release.
3000 	 */
3001 	if (ack_kref) {
3002 		kref_get(&se_cmd->cmd_kref);
3003 		se_cmd->se_cmd_flags |= SCF_ACK_KREF;
3004 	}
3005 
3006 	/*
3007 	 * Users like xcopy do not use counters since they never do a stop
3008 	 * and wait.
3009 	 */
3010 	if (se_cmd->cmd_cnt) {
3011 		if (!percpu_ref_tryget_live(&se_cmd->cmd_cnt->refcnt))
3012 			ret = -ESHUTDOWN;
3013 	}
3014 	if (ret && ack_kref)
3015 		target_put_sess_cmd(se_cmd);
3016 
3017 	return ret;
3018 }
3019 EXPORT_SYMBOL(target_get_sess_cmd);
3020 
3021 static void target_free_cmd_mem(struct se_cmd *cmd)
3022 {
3023 	transport_free_pages(cmd);
3024 
3025 	if (cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
3026 		core_tmr_release_req(cmd->se_tmr_req);
3027 	if (cmd->t_task_cdb != cmd->__t_task_cdb)
3028 		kfree(cmd->t_task_cdb);
3029 }
3030 
3031 static void target_release_cmd_kref(struct kref *kref)
3032 {
3033 	struct se_cmd *se_cmd = container_of(kref, struct se_cmd, cmd_kref);
3034 	struct target_cmd_counter *cmd_cnt = se_cmd->cmd_cnt;
3035 	struct completion *free_compl = se_cmd->free_compl;
3036 	struct completion *abrt_compl = se_cmd->abrt_compl;
3037 
3038 	target_free_cmd_mem(se_cmd);
3039 	se_cmd->se_tfo->release_cmd(se_cmd);
3040 	if (free_compl)
3041 		complete(free_compl);
3042 	if (abrt_compl)
3043 		complete(abrt_compl);
3044 
3045 	if (cmd_cnt)
3046 		percpu_ref_put(&cmd_cnt->refcnt);
3047 }
3048 
3049 /**
3050  * target_put_sess_cmd - decrease the command reference count
3051  * @se_cmd:	command to drop a reference from
3052  *
3053  * Returns 1 if and only if this target_put_sess_cmd() call caused the
3054  * refcount to drop to zero. Returns zero otherwise.
3055  */
3056 int target_put_sess_cmd(struct se_cmd *se_cmd)
3057 {
3058 	return kref_put(&se_cmd->cmd_kref, target_release_cmd_kref);
3059 }
3060 EXPORT_SYMBOL(target_put_sess_cmd);
3061 
3062 static const char *data_dir_name(enum dma_data_direction d)
3063 {
3064 	switch (d) {
3065 	case DMA_BIDIRECTIONAL:	return "BIDI";
3066 	case DMA_TO_DEVICE:	return "WRITE";
3067 	case DMA_FROM_DEVICE:	return "READ";
3068 	case DMA_NONE:		return "NONE";
3069 	}
3070 
3071 	return "(?)";
3072 }
3073 
3074 static const char *cmd_state_name(enum transport_state_table t)
3075 {
3076 	switch (t) {
3077 	case TRANSPORT_NO_STATE:	return "NO_STATE";
3078 	case TRANSPORT_NEW_CMD:		return "NEW_CMD";
3079 	case TRANSPORT_WRITE_PENDING:	return "WRITE_PENDING";
3080 	case TRANSPORT_PROCESSING:	return "PROCESSING";
3081 	case TRANSPORT_COMPLETE:	return "COMPLETE";
3082 	case TRANSPORT_ISTATE_PROCESSING:
3083 					return "ISTATE_PROCESSING";
3084 	case TRANSPORT_COMPLETE_QF_WP:	return "COMPLETE_QF_WP";
3085 	case TRANSPORT_COMPLETE_QF_OK:	return "COMPLETE_QF_OK";
3086 	case TRANSPORT_COMPLETE_QF_ERR:	return "COMPLETE_QF_ERR";
3087 	}
3088 
3089 	return "(?)";
3090 }
3091 
3092 static void target_append_str(char **str, const char *txt)
3093 {
3094 	char *prev = *str;
3095 
3096 	*str = *str ? kasprintf(GFP_ATOMIC, "%s,%s", *str, txt) :
3097 		kstrdup(txt, GFP_ATOMIC);
3098 	kfree(prev);
3099 }
3100 
3101 /*
3102  * Convert a transport state bitmask into a string. The caller is
3103  * responsible for freeing the returned pointer.
3104  */
3105 static char *target_ts_to_str(u32 ts)
3106 {
3107 	char *str = NULL;
3108 
3109 	if (ts & CMD_T_ABORTED)
3110 		target_append_str(&str, "aborted");
3111 	if (ts & CMD_T_ACTIVE)
3112 		target_append_str(&str, "active");
3113 	if (ts & CMD_T_COMPLETE)
3114 		target_append_str(&str, "complete");
3115 	if (ts & CMD_T_SENT)
3116 		target_append_str(&str, "sent");
3117 	if (ts & CMD_T_STOP)
3118 		target_append_str(&str, "stop");
3119 	if (ts & CMD_T_FABRIC_STOP)
3120 		target_append_str(&str, "fabric_stop");
3121 
3122 	return str;
3123 }
3124 
3125 static const char *target_tmf_name(enum tcm_tmreq_table tmf)
3126 {
3127 	switch (tmf) {
3128 	case TMR_ABORT_TASK:		return "ABORT_TASK";
3129 	case TMR_ABORT_TASK_SET:	return "ABORT_TASK_SET";
3130 	case TMR_CLEAR_ACA:		return "CLEAR_ACA";
3131 	case TMR_CLEAR_TASK_SET:	return "CLEAR_TASK_SET";
3132 	case TMR_LUN_RESET:		return "LUN_RESET";
3133 	case TMR_TARGET_WARM_RESET:	return "TARGET_WARM_RESET";
3134 	case TMR_TARGET_COLD_RESET:	return "TARGET_COLD_RESET";
3135 	case TMR_LUN_RESET_PRO:		return "LUN_RESET_PRO";
3136 	case TMR_UNKNOWN:		break;
3137 	}
3138 	return "(?)";
3139 }
3140 
3141 void target_show_cmd(const char *pfx, struct se_cmd *cmd)
3142 {
3143 	char *ts_str = target_ts_to_str(cmd->transport_state);
3144 	const u8 *cdb = cmd->t_task_cdb;
3145 	struct se_tmr_req *tmf = cmd->se_tmr_req;
3146 
3147 	if (!(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)) {
3148 		pr_debug("%scmd %#02x:%#02x with tag %#llx dir %s i_state %d t_state %s len %d refcnt %d transport_state %s\n",
3149 			 pfx, cdb[0], cdb[1], cmd->tag,
3150 			 data_dir_name(cmd->data_direction),
3151 			 cmd->se_tfo->get_cmd_state(cmd),
3152 			 cmd_state_name(cmd->t_state), cmd->data_length,
3153 			 kref_read(&cmd->cmd_kref), ts_str);
3154 	} else {
3155 		pr_debug("%stmf %s with tag %#llx ref_task_tag %#llx i_state %d t_state %s refcnt %d transport_state %s\n",
3156 			 pfx, target_tmf_name(tmf->function), cmd->tag,
3157 			 tmf->ref_task_tag, cmd->se_tfo->get_cmd_state(cmd),
3158 			 cmd_state_name(cmd->t_state),
3159 			 kref_read(&cmd->cmd_kref), ts_str);
3160 	}
3161 	kfree(ts_str);
3162 }
3163 EXPORT_SYMBOL(target_show_cmd);
3164 
3165 static void target_stop_cmd_counter_confirm(struct percpu_ref *ref)
3166 {
3167 	struct target_cmd_counter *cmd_cnt = container_of(ref,
3168 						struct target_cmd_counter,
3169 						refcnt);
3170 	complete_all(&cmd_cnt->stop_done);
3171 }
3172 
3173 /**
3174  * target_stop_cmd_counter - Stop new IO from being added to the counter.
3175  * @cmd_cnt: counter to stop
3176  */
3177 void target_stop_cmd_counter(struct target_cmd_counter *cmd_cnt)
3178 {
3179 	pr_debug("Stopping command counter.\n");
3180 	if (!atomic_cmpxchg(&cmd_cnt->stopped, 0, 1))
3181 		percpu_ref_kill_and_confirm(&cmd_cnt->refcnt,
3182 					    target_stop_cmd_counter_confirm);
3183 }
3184 EXPORT_SYMBOL_GPL(target_stop_cmd_counter);
3185 
3186 /**
3187  * target_stop_session - Stop new IO from being queued on the session.
3188  * @se_sess: session to stop
3189  */
3190 void target_stop_session(struct se_session *se_sess)
3191 {
3192 	target_stop_cmd_counter(se_sess->cmd_cnt);
3193 }
3194 EXPORT_SYMBOL(target_stop_session);
3195 
3196 /**
3197  * target_wait_for_cmds - Wait for outstanding cmds.
3198  * @cmd_cnt: counter to wait for active I/O for.
3199  */
3200 void target_wait_for_cmds(struct target_cmd_counter *cmd_cnt)
3201 {
3202 	int ret;
3203 
3204 	WARN_ON_ONCE(!atomic_read(&cmd_cnt->stopped));
3205 
3206 	do {
3207 		pr_debug("Waiting for running cmds to complete.\n");
3208 		ret = wait_event_timeout(cmd_cnt->refcnt_wq,
3209 					 percpu_ref_is_zero(&cmd_cnt->refcnt),
3210 					 180 * HZ);
3211 	} while (ret <= 0);
3212 
3213 	wait_for_completion(&cmd_cnt->stop_done);
3214 	pr_debug("Waiting for cmds done.\n");
3215 }
3216 EXPORT_SYMBOL_GPL(target_wait_for_cmds);
3217 
3218 /**
3219  * target_wait_for_sess_cmds - Wait for outstanding commands
3220  * @se_sess: session to wait for active I/O
3221  */
3222 void target_wait_for_sess_cmds(struct se_session *se_sess)
3223 {
3224 	target_wait_for_cmds(se_sess->cmd_cnt);
3225 }
3226 EXPORT_SYMBOL(target_wait_for_sess_cmds);
3227 
3228 /*
3229  * Prevent that new percpu_ref_tryget_live() calls succeed and wait until
3230  * all references to the LUN have been released. Called during LUN shutdown.
3231  */
3232 void transport_clear_lun_ref(struct se_lun *lun)
3233 {
3234 	percpu_ref_kill(&lun->lun_ref);
3235 	wait_for_completion(&lun->lun_shutdown_comp);
3236 }
3237 
3238 static bool
3239 __transport_wait_for_tasks(struct se_cmd *cmd, bool fabric_stop,
3240 			   bool *aborted, bool *tas, unsigned long *flags)
3241 	__releases(&cmd->t_state_lock)
3242 	__acquires(&cmd->t_state_lock)
3243 {
3244 	lockdep_assert_held(&cmd->t_state_lock);
3245 
3246 	if (fabric_stop)
3247 		cmd->transport_state |= CMD_T_FABRIC_STOP;
3248 
3249 	if (cmd->transport_state & CMD_T_ABORTED)
3250 		*aborted = true;
3251 
3252 	if (cmd->transport_state & CMD_T_TAS)
3253 		*tas = true;
3254 
3255 	if (!(cmd->se_cmd_flags & SCF_SE_LUN_CMD) &&
3256 	    !(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
3257 		return false;
3258 
3259 	if (!(cmd->se_cmd_flags & SCF_SUPPORTED_SAM_OPCODE) &&
3260 	    !(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
3261 		return false;
3262 
3263 	if (!(cmd->transport_state & CMD_T_ACTIVE))
3264 		return false;
3265 
3266 	if (fabric_stop && *aborted)
3267 		return false;
3268 
3269 	cmd->transport_state |= CMD_T_STOP;
3270 
3271 	target_show_cmd("wait_for_tasks: Stopping ", cmd);
3272 
3273 	spin_unlock_irqrestore(&cmd->t_state_lock, *flags);
3274 
3275 	while (!wait_for_completion_timeout(&cmd->t_transport_stop_comp,
3276 					    180 * HZ))
3277 		target_show_cmd("wait for tasks: ", cmd);
3278 
3279 	spin_lock_irqsave(&cmd->t_state_lock, *flags);
3280 	cmd->transport_state &= ~(CMD_T_ACTIVE | CMD_T_STOP);
3281 
3282 	pr_debug("wait_for_tasks: Stopped wait_for_completion(&cmd->"
3283 		 "t_transport_stop_comp) for ITT: 0x%08llx\n", cmd->tag);
3284 
3285 	return true;
3286 }
3287 
3288 /**
3289  * transport_wait_for_tasks - set CMD_T_STOP and wait for t_transport_stop_comp
3290  * @cmd: command to wait on
3291  */
3292 bool transport_wait_for_tasks(struct se_cmd *cmd)
3293 {
3294 	unsigned long flags;
3295 	bool ret, aborted = false, tas = false;
3296 
3297 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3298 	ret = __transport_wait_for_tasks(cmd, false, &aborted, &tas, &flags);
3299 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3300 
3301 	return ret;
3302 }
3303 EXPORT_SYMBOL(transport_wait_for_tasks);
3304 
3305 struct sense_detail {
3306 	u8 key;
3307 	u8 asc;
3308 	u8 ascq;
3309 	bool add_sense_info;
3310 };
3311 
3312 static const struct sense_detail sense_detail_table[] = {
3313 	[TCM_NO_SENSE] = {
3314 		.key = NOT_READY
3315 	},
3316 	[TCM_NON_EXISTENT_LUN] = {
3317 		.key = ILLEGAL_REQUEST,
3318 		.asc = 0x25 /* LOGICAL UNIT NOT SUPPORTED */
3319 	},
3320 	[TCM_UNSUPPORTED_SCSI_OPCODE] = {
3321 		.key = ILLEGAL_REQUEST,
3322 		.asc = 0x20, /* INVALID COMMAND OPERATION CODE */
3323 	},
3324 	[TCM_SECTOR_COUNT_TOO_MANY] = {
3325 		.key = ILLEGAL_REQUEST,
3326 		.asc = 0x20, /* INVALID COMMAND OPERATION CODE */
3327 	},
3328 	[TCM_UNKNOWN_MODE_PAGE] = {
3329 		.key = ILLEGAL_REQUEST,
3330 		.asc = 0x24, /* INVALID FIELD IN CDB */
3331 	},
3332 	[TCM_CHECK_CONDITION_ABORT_CMD] = {
3333 		.key = ABORTED_COMMAND,
3334 		.asc = 0x29, /* BUS DEVICE RESET FUNCTION OCCURRED */
3335 		.ascq = 0x03,
3336 	},
3337 	[TCM_INCORRECT_AMOUNT_OF_DATA] = {
3338 		.key = ABORTED_COMMAND,
3339 		.asc = 0x0c, /* WRITE ERROR */
3340 		.ascq = 0x0d, /* NOT ENOUGH UNSOLICITED DATA */
3341 	},
3342 	[TCM_INVALID_CDB_FIELD] = {
3343 		.key = ILLEGAL_REQUEST,
3344 		.asc = 0x24, /* INVALID FIELD IN CDB */
3345 	},
3346 	[TCM_INVALID_PARAMETER_LIST] = {
3347 		.key = ILLEGAL_REQUEST,
3348 		.asc = 0x26, /* INVALID FIELD IN PARAMETER LIST */
3349 	},
3350 	[TCM_TOO_MANY_TARGET_DESCS] = {
3351 		.key = ILLEGAL_REQUEST,
3352 		.asc = 0x26,
3353 		.ascq = 0x06, /* TOO MANY TARGET DESCRIPTORS */
3354 	},
3355 	[TCM_UNSUPPORTED_TARGET_DESC_TYPE_CODE] = {
3356 		.key = ILLEGAL_REQUEST,
3357 		.asc = 0x26,
3358 		.ascq = 0x07, /* UNSUPPORTED TARGET DESCRIPTOR TYPE CODE */
3359 	},
3360 	[TCM_TOO_MANY_SEGMENT_DESCS] = {
3361 		.key = ILLEGAL_REQUEST,
3362 		.asc = 0x26,
3363 		.ascq = 0x08, /* TOO MANY SEGMENT DESCRIPTORS */
3364 	},
3365 	[TCM_UNSUPPORTED_SEGMENT_DESC_TYPE_CODE] = {
3366 		.key = ILLEGAL_REQUEST,
3367 		.asc = 0x26,
3368 		.ascq = 0x09, /* UNSUPPORTED SEGMENT DESCRIPTOR TYPE CODE */
3369 	},
3370 	[TCM_PARAMETER_LIST_LENGTH_ERROR] = {
3371 		.key = ILLEGAL_REQUEST,
3372 		.asc = 0x1a, /* PARAMETER LIST LENGTH ERROR */
3373 	},
3374 	[TCM_UNEXPECTED_UNSOLICITED_DATA] = {
3375 		.key = ILLEGAL_REQUEST,
3376 		.asc = 0x0c, /* WRITE ERROR */
3377 		.ascq = 0x0c, /* UNEXPECTED_UNSOLICITED_DATA */
3378 	},
3379 	[TCM_SERVICE_CRC_ERROR] = {
3380 		.key = ABORTED_COMMAND,
3381 		.asc = 0x47, /* PROTOCOL SERVICE CRC ERROR */
3382 		.ascq = 0x05, /* N/A */
3383 	},
3384 	[TCM_SNACK_REJECTED] = {
3385 		.key = ABORTED_COMMAND,
3386 		.asc = 0x11, /* READ ERROR */
3387 		.ascq = 0x13, /* FAILED RETRANSMISSION REQUEST */
3388 	},
3389 	[TCM_WRITE_PROTECTED] = {
3390 		.key = DATA_PROTECT,
3391 		.asc = 0x27, /* WRITE PROTECTED */
3392 	},
3393 	[TCM_ADDRESS_OUT_OF_RANGE] = {
3394 		.key = ILLEGAL_REQUEST,
3395 		.asc = 0x21, /* LOGICAL BLOCK ADDRESS OUT OF RANGE */
3396 	},
3397 	[TCM_CHECK_CONDITION_UNIT_ATTENTION] = {
3398 		.key = UNIT_ATTENTION,
3399 	},
3400 	[TCM_MISCOMPARE_VERIFY] = {
3401 		.key = MISCOMPARE,
3402 		.asc = 0x1d, /* MISCOMPARE DURING VERIFY OPERATION */
3403 		.ascq = 0x00,
3404 		.add_sense_info = true,
3405 	},
3406 	[TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED] = {
3407 		.key = ABORTED_COMMAND,
3408 		.asc = 0x10,
3409 		.ascq = 0x01, /* LOGICAL BLOCK GUARD CHECK FAILED */
3410 		.add_sense_info = true,
3411 	},
3412 	[TCM_LOGICAL_BLOCK_APP_TAG_CHECK_FAILED] = {
3413 		.key = ABORTED_COMMAND,
3414 		.asc = 0x10,
3415 		.ascq = 0x02, /* LOGICAL BLOCK APPLICATION TAG CHECK FAILED */
3416 		.add_sense_info = true,
3417 	},
3418 	[TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED] = {
3419 		.key = ABORTED_COMMAND,
3420 		.asc = 0x10,
3421 		.ascq = 0x03, /* LOGICAL BLOCK REFERENCE TAG CHECK FAILED */
3422 		.add_sense_info = true,
3423 	},
3424 	[TCM_COPY_TARGET_DEVICE_NOT_REACHABLE] = {
3425 		.key = COPY_ABORTED,
3426 		.asc = 0x0d,
3427 		.ascq = 0x02, /* COPY TARGET DEVICE NOT REACHABLE */
3428 
3429 	},
3430 	[TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE] = {
3431 		/*
3432 		 * Returning ILLEGAL REQUEST would cause immediate IO errors on
3433 		 * Solaris initiators.  Returning NOT READY instead means the
3434 		 * operations will be retried a finite number of times and we
3435 		 * can survive intermittent errors.
3436 		 */
3437 		.key = NOT_READY,
3438 		.asc = 0x08, /* LOGICAL UNIT COMMUNICATION FAILURE */
3439 	},
3440 	[TCM_INSUFFICIENT_REGISTRATION_RESOURCES] = {
3441 		/*
3442 		 * From spc4r22 section5.7.7,5.7.8
3443 		 * If a PERSISTENT RESERVE OUT command with a REGISTER service action
3444 		 * or a REGISTER AND IGNORE EXISTING KEY service action or
3445 		 * REGISTER AND MOVE service actionis attempted,
3446 		 * but there are insufficient device server resources to complete the
3447 		 * operation, then the command shall be terminated with CHECK CONDITION
3448 		 * status, with the sense key set to ILLEGAL REQUEST,and the additonal
3449 		 * sense code set to INSUFFICIENT REGISTRATION RESOURCES.
3450 		 */
3451 		.key = ILLEGAL_REQUEST,
3452 		.asc = 0x55,
3453 		.ascq = 0x04, /* INSUFFICIENT REGISTRATION RESOURCES */
3454 	},
3455 	[TCM_INVALID_FIELD_IN_COMMAND_IU] = {
3456 		.key = ILLEGAL_REQUEST,
3457 		.asc = 0x0e,
3458 		.ascq = 0x03, /* INVALID FIELD IN COMMAND INFORMATION UNIT */
3459 	},
3460 	[TCM_ALUA_TG_PT_STANDBY] = {
3461 		.key = NOT_READY,
3462 		.asc = 0x04,
3463 		.ascq = ASCQ_04H_ALUA_TG_PT_STANDBY,
3464 	},
3465 	[TCM_ALUA_TG_PT_UNAVAILABLE] = {
3466 		.key = NOT_READY,
3467 		.asc = 0x04,
3468 		.ascq = ASCQ_04H_ALUA_TG_PT_UNAVAILABLE,
3469 	},
3470 	[TCM_ALUA_STATE_TRANSITION] = {
3471 		.key = NOT_READY,
3472 		.asc = 0x04,
3473 		.ascq = ASCQ_04H_ALUA_STATE_TRANSITION,
3474 	},
3475 	[TCM_ALUA_OFFLINE] = {
3476 		.key = NOT_READY,
3477 		.asc = 0x04,
3478 		.ascq = ASCQ_04H_ALUA_OFFLINE,
3479 	},
3480 };
3481 
3482 /**
3483  * translate_sense_reason - translate a sense reason into T10 key, asc and ascq
3484  * @cmd: SCSI command in which the resulting sense buffer or SCSI status will
3485  *   be stored.
3486  * @reason: LIO sense reason code. If this argument has the value
3487  *   TCM_CHECK_CONDITION_UNIT_ATTENTION, try to dequeue a unit attention. If
3488  *   dequeuing a unit attention fails due to multiple commands being processed
3489  *   concurrently, set the command status to BUSY.
3490  *
3491  * Return: 0 upon success or -EINVAL if the sense buffer is too small.
3492  */
3493 static void translate_sense_reason(struct se_cmd *cmd, sense_reason_t reason)
3494 {
3495 	const struct sense_detail *sd;
3496 	u8 *buffer = cmd->sense_buffer;
3497 	int r = (__force int)reason;
3498 	u8 key, asc, ascq;
3499 	bool desc_format = target_sense_desc_format(cmd->se_dev);
3500 
3501 	if (r < ARRAY_SIZE(sense_detail_table) && sense_detail_table[r].key)
3502 		sd = &sense_detail_table[r];
3503 	else
3504 		sd = &sense_detail_table[(__force int)
3505 				       TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE];
3506 
3507 	key = sd->key;
3508 	if (reason == TCM_CHECK_CONDITION_UNIT_ATTENTION) {
3509 		if (!core_scsi3_ua_for_check_condition(cmd, &key, &asc,
3510 						       &ascq)) {
3511 			cmd->scsi_status = SAM_STAT_BUSY;
3512 			return;
3513 		}
3514 	} else {
3515 		WARN_ON_ONCE(sd->asc == 0);
3516 		asc = sd->asc;
3517 		ascq = sd->ascq;
3518 	}
3519 
3520 	cmd->se_cmd_flags |= SCF_EMULATED_TASK_SENSE;
3521 	cmd->scsi_status = SAM_STAT_CHECK_CONDITION;
3522 	cmd->scsi_sense_length  = TRANSPORT_SENSE_BUFFER;
3523 	scsi_build_sense_buffer(desc_format, buffer, key, asc, ascq);
3524 	if (sd->add_sense_info)
3525 		WARN_ON_ONCE(scsi_set_sense_information(buffer,
3526 							cmd->scsi_sense_length,
3527 							cmd->sense_info) < 0);
3528 }
3529 
3530 int
3531 transport_send_check_condition_and_sense(struct se_cmd *cmd,
3532 		sense_reason_t reason, int from_transport)
3533 {
3534 	unsigned long flags;
3535 
3536 	WARN_ON_ONCE(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB);
3537 
3538 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3539 	if (cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION) {
3540 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3541 		return 0;
3542 	}
3543 	cmd->se_cmd_flags |= SCF_SENT_CHECK_CONDITION;
3544 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3545 
3546 	if (!from_transport)
3547 		translate_sense_reason(cmd, reason);
3548 
3549 	trace_target_cmd_complete(cmd);
3550 	return cmd->se_tfo->queue_status(cmd);
3551 }
3552 EXPORT_SYMBOL(transport_send_check_condition_and_sense);
3553 
3554 /**
3555  * target_send_busy - Send SCSI BUSY status back to the initiator
3556  * @cmd: SCSI command for which to send a BUSY reply.
3557  *
3558  * Note: Only call this function if target_submit_cmd*() failed.
3559  */
3560 int target_send_busy(struct se_cmd *cmd)
3561 {
3562 	WARN_ON_ONCE(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB);
3563 
3564 	cmd->scsi_status = SAM_STAT_BUSY;
3565 	trace_target_cmd_complete(cmd);
3566 	return cmd->se_tfo->queue_status(cmd);
3567 }
3568 EXPORT_SYMBOL(target_send_busy);
3569 
3570 static void target_tmr_work(struct work_struct *work)
3571 {
3572 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
3573 	struct se_device *dev = cmd->se_dev;
3574 	struct se_tmr_req *tmr = cmd->se_tmr_req;
3575 	int ret;
3576 
3577 	if (cmd->transport_state & CMD_T_ABORTED)
3578 		goto aborted;
3579 
3580 	switch (tmr->function) {
3581 	case TMR_ABORT_TASK:
3582 		core_tmr_abort_task(dev, tmr, cmd->se_sess);
3583 		break;
3584 	case TMR_ABORT_TASK_SET:
3585 	case TMR_CLEAR_ACA:
3586 	case TMR_CLEAR_TASK_SET:
3587 		tmr->response = TMR_TASK_MGMT_FUNCTION_NOT_SUPPORTED;
3588 		break;
3589 	case TMR_LUN_RESET:
3590 		ret = core_tmr_lun_reset(dev, tmr, NULL, NULL);
3591 		tmr->response = (!ret) ? TMR_FUNCTION_COMPLETE :
3592 					 TMR_FUNCTION_REJECTED;
3593 		if (tmr->response == TMR_FUNCTION_COMPLETE) {
3594 			target_dev_ua_allocate(dev, 0x29,
3595 					       ASCQ_29H_BUS_DEVICE_RESET_FUNCTION_OCCURRED);
3596 		}
3597 		break;
3598 	case TMR_TARGET_WARM_RESET:
3599 		tmr->response = TMR_FUNCTION_REJECTED;
3600 		break;
3601 	case TMR_TARGET_COLD_RESET:
3602 		tmr->response = TMR_FUNCTION_REJECTED;
3603 		break;
3604 	default:
3605 		pr_err("Unknown TMR function: 0x%02x.\n",
3606 				tmr->function);
3607 		tmr->response = TMR_FUNCTION_REJECTED;
3608 		break;
3609 	}
3610 
3611 	if (cmd->transport_state & CMD_T_ABORTED)
3612 		goto aborted;
3613 
3614 	cmd->se_tfo->queue_tm_rsp(cmd);
3615 
3616 	transport_lun_remove_cmd(cmd);
3617 	transport_cmd_check_stop_to_fabric(cmd);
3618 	return;
3619 
3620 aborted:
3621 	target_handle_abort(cmd);
3622 }
3623 
3624 int transport_generic_handle_tmr(
3625 	struct se_cmd *cmd)
3626 {
3627 	unsigned long flags;
3628 	bool aborted = false;
3629 
3630 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3631 	if (cmd->transport_state & CMD_T_ABORTED) {
3632 		aborted = true;
3633 	} else {
3634 		cmd->t_state = TRANSPORT_ISTATE_PROCESSING;
3635 		cmd->transport_state |= CMD_T_ACTIVE;
3636 	}
3637 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3638 
3639 	if (aborted) {
3640 		pr_warn_ratelimited("handle_tmr caught CMD_T_ABORTED TMR %d ref_tag: %llu tag: %llu\n",
3641 				    cmd->se_tmr_req->function,
3642 				    cmd->se_tmr_req->ref_task_tag, cmd->tag);
3643 		target_handle_abort(cmd);
3644 		return 0;
3645 	}
3646 
3647 	INIT_WORK(&cmd->work, target_tmr_work);
3648 	schedule_work(&cmd->work);
3649 	return 0;
3650 }
3651 EXPORT_SYMBOL(transport_generic_handle_tmr);
3652 
3653 bool
3654 target_check_wce(struct se_device *dev)
3655 {
3656 	bool wce = false;
3657 
3658 	if (dev->transport->get_write_cache)
3659 		wce = dev->transport->get_write_cache(dev);
3660 	else if (dev->dev_attrib.emulate_write_cache > 0)
3661 		wce = true;
3662 
3663 	return wce;
3664 }
3665 
3666 bool
3667 target_check_fua(struct se_device *dev)
3668 {
3669 	return target_check_wce(dev) && dev->dev_attrib.emulate_fua_write > 0;
3670 }
3671