xref: /linux/drivers/target/target_core_transport.c (revision bd628c1bed7902ec1f24ba0fe70758949146abbe)
1 /*******************************************************************************
2  * Filename:  target_core_transport.c
3  *
4  * This file contains the Generic Target Engine Core.
5  *
6  * (c) Copyright 2002-2013 Datera, Inc.
7  *
8  * Nicholas A. Bellinger <nab@kernel.org>
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License as published by
12  * the Free Software Foundation; either version 2 of the License, or
13  * (at your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18  * GNU General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with this program; if not, write to the Free Software
22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
23  *
24  ******************************************************************************/
25 
26 #include <linux/net.h>
27 #include <linux/delay.h>
28 #include <linux/string.h>
29 #include <linux/timer.h>
30 #include <linux/slab.h>
31 #include <linux/spinlock.h>
32 #include <linux/kthread.h>
33 #include <linux/in.h>
34 #include <linux/cdrom.h>
35 #include <linux/module.h>
36 #include <linux/ratelimit.h>
37 #include <linux/vmalloc.h>
38 #include <asm/unaligned.h>
39 #include <net/sock.h>
40 #include <net/tcp.h>
41 #include <scsi/scsi_proto.h>
42 #include <scsi/scsi_common.h>
43 
44 #include <target/target_core_base.h>
45 #include <target/target_core_backend.h>
46 #include <target/target_core_fabric.h>
47 
48 #include "target_core_internal.h"
49 #include "target_core_alua.h"
50 #include "target_core_pr.h"
51 #include "target_core_ua.h"
52 
53 #define CREATE_TRACE_POINTS
54 #include <trace/events/target.h>
55 
56 static struct workqueue_struct *target_completion_wq;
57 static struct kmem_cache *se_sess_cache;
58 struct kmem_cache *se_ua_cache;
59 struct kmem_cache *t10_pr_reg_cache;
60 struct kmem_cache *t10_alua_lu_gp_cache;
61 struct kmem_cache *t10_alua_lu_gp_mem_cache;
62 struct kmem_cache *t10_alua_tg_pt_gp_cache;
63 struct kmem_cache *t10_alua_lba_map_cache;
64 struct kmem_cache *t10_alua_lba_map_mem_cache;
65 
66 static void transport_complete_task_attr(struct se_cmd *cmd);
67 static void translate_sense_reason(struct se_cmd *cmd, sense_reason_t reason);
68 static void transport_handle_queue_full(struct se_cmd *cmd,
69 		struct se_device *dev, int err, bool write_pending);
70 static void target_complete_ok_work(struct work_struct *work);
71 
72 int init_se_kmem_caches(void)
73 {
74 	se_sess_cache = kmem_cache_create("se_sess_cache",
75 			sizeof(struct se_session), __alignof__(struct se_session),
76 			0, NULL);
77 	if (!se_sess_cache) {
78 		pr_err("kmem_cache_create() for struct se_session"
79 				" failed\n");
80 		goto out;
81 	}
82 	se_ua_cache = kmem_cache_create("se_ua_cache",
83 			sizeof(struct se_ua), __alignof__(struct se_ua),
84 			0, NULL);
85 	if (!se_ua_cache) {
86 		pr_err("kmem_cache_create() for struct se_ua failed\n");
87 		goto out_free_sess_cache;
88 	}
89 	t10_pr_reg_cache = kmem_cache_create("t10_pr_reg_cache",
90 			sizeof(struct t10_pr_registration),
91 			__alignof__(struct t10_pr_registration), 0, NULL);
92 	if (!t10_pr_reg_cache) {
93 		pr_err("kmem_cache_create() for struct t10_pr_registration"
94 				" failed\n");
95 		goto out_free_ua_cache;
96 	}
97 	t10_alua_lu_gp_cache = kmem_cache_create("t10_alua_lu_gp_cache",
98 			sizeof(struct t10_alua_lu_gp), __alignof__(struct t10_alua_lu_gp),
99 			0, NULL);
100 	if (!t10_alua_lu_gp_cache) {
101 		pr_err("kmem_cache_create() for t10_alua_lu_gp_cache"
102 				" failed\n");
103 		goto out_free_pr_reg_cache;
104 	}
105 	t10_alua_lu_gp_mem_cache = kmem_cache_create("t10_alua_lu_gp_mem_cache",
106 			sizeof(struct t10_alua_lu_gp_member),
107 			__alignof__(struct t10_alua_lu_gp_member), 0, NULL);
108 	if (!t10_alua_lu_gp_mem_cache) {
109 		pr_err("kmem_cache_create() for t10_alua_lu_gp_mem_"
110 				"cache failed\n");
111 		goto out_free_lu_gp_cache;
112 	}
113 	t10_alua_tg_pt_gp_cache = kmem_cache_create("t10_alua_tg_pt_gp_cache",
114 			sizeof(struct t10_alua_tg_pt_gp),
115 			__alignof__(struct t10_alua_tg_pt_gp), 0, NULL);
116 	if (!t10_alua_tg_pt_gp_cache) {
117 		pr_err("kmem_cache_create() for t10_alua_tg_pt_gp_"
118 				"cache failed\n");
119 		goto out_free_lu_gp_mem_cache;
120 	}
121 	t10_alua_lba_map_cache = kmem_cache_create(
122 			"t10_alua_lba_map_cache",
123 			sizeof(struct t10_alua_lba_map),
124 			__alignof__(struct t10_alua_lba_map), 0, NULL);
125 	if (!t10_alua_lba_map_cache) {
126 		pr_err("kmem_cache_create() for t10_alua_lba_map_"
127 				"cache failed\n");
128 		goto out_free_tg_pt_gp_cache;
129 	}
130 	t10_alua_lba_map_mem_cache = kmem_cache_create(
131 			"t10_alua_lba_map_mem_cache",
132 			sizeof(struct t10_alua_lba_map_member),
133 			__alignof__(struct t10_alua_lba_map_member), 0, NULL);
134 	if (!t10_alua_lba_map_mem_cache) {
135 		pr_err("kmem_cache_create() for t10_alua_lba_map_mem_"
136 				"cache failed\n");
137 		goto out_free_lba_map_cache;
138 	}
139 
140 	target_completion_wq = alloc_workqueue("target_completion",
141 					       WQ_MEM_RECLAIM, 0);
142 	if (!target_completion_wq)
143 		goto out_free_lba_map_mem_cache;
144 
145 	return 0;
146 
147 out_free_lba_map_mem_cache:
148 	kmem_cache_destroy(t10_alua_lba_map_mem_cache);
149 out_free_lba_map_cache:
150 	kmem_cache_destroy(t10_alua_lba_map_cache);
151 out_free_tg_pt_gp_cache:
152 	kmem_cache_destroy(t10_alua_tg_pt_gp_cache);
153 out_free_lu_gp_mem_cache:
154 	kmem_cache_destroy(t10_alua_lu_gp_mem_cache);
155 out_free_lu_gp_cache:
156 	kmem_cache_destroy(t10_alua_lu_gp_cache);
157 out_free_pr_reg_cache:
158 	kmem_cache_destroy(t10_pr_reg_cache);
159 out_free_ua_cache:
160 	kmem_cache_destroy(se_ua_cache);
161 out_free_sess_cache:
162 	kmem_cache_destroy(se_sess_cache);
163 out:
164 	return -ENOMEM;
165 }
166 
167 void release_se_kmem_caches(void)
168 {
169 	destroy_workqueue(target_completion_wq);
170 	kmem_cache_destroy(se_sess_cache);
171 	kmem_cache_destroy(se_ua_cache);
172 	kmem_cache_destroy(t10_pr_reg_cache);
173 	kmem_cache_destroy(t10_alua_lu_gp_cache);
174 	kmem_cache_destroy(t10_alua_lu_gp_mem_cache);
175 	kmem_cache_destroy(t10_alua_tg_pt_gp_cache);
176 	kmem_cache_destroy(t10_alua_lba_map_cache);
177 	kmem_cache_destroy(t10_alua_lba_map_mem_cache);
178 }
179 
180 /* This code ensures unique mib indexes are handed out. */
181 static DEFINE_SPINLOCK(scsi_mib_index_lock);
182 static u32 scsi_mib_index[SCSI_INDEX_TYPE_MAX];
183 
184 /*
185  * Allocate a new row index for the entry type specified
186  */
187 u32 scsi_get_new_index(scsi_index_t type)
188 {
189 	u32 new_index;
190 
191 	BUG_ON((type < 0) || (type >= SCSI_INDEX_TYPE_MAX));
192 
193 	spin_lock(&scsi_mib_index_lock);
194 	new_index = ++scsi_mib_index[type];
195 	spin_unlock(&scsi_mib_index_lock);
196 
197 	return new_index;
198 }
199 
200 void transport_subsystem_check_init(void)
201 {
202 	int ret;
203 	static int sub_api_initialized;
204 
205 	if (sub_api_initialized)
206 		return;
207 
208 	ret = IS_ENABLED(CONFIG_TCM_IBLOCK) && request_module("target_core_iblock");
209 	if (ret != 0)
210 		pr_err("Unable to load target_core_iblock\n");
211 
212 	ret = IS_ENABLED(CONFIG_TCM_FILEIO) && request_module("target_core_file");
213 	if (ret != 0)
214 		pr_err("Unable to load target_core_file\n");
215 
216 	ret = IS_ENABLED(CONFIG_TCM_PSCSI) && request_module("target_core_pscsi");
217 	if (ret != 0)
218 		pr_err("Unable to load target_core_pscsi\n");
219 
220 	ret = IS_ENABLED(CONFIG_TCM_USER2) && request_module("target_core_user");
221 	if (ret != 0)
222 		pr_err("Unable to load target_core_user\n");
223 
224 	sub_api_initialized = 1;
225 }
226 
227 static void target_release_sess_cmd_refcnt(struct percpu_ref *ref)
228 {
229 	struct se_session *sess = container_of(ref, typeof(*sess), cmd_count);
230 
231 	wake_up(&sess->cmd_list_wq);
232 }
233 
234 /**
235  * transport_init_session - initialize a session object
236  * @se_sess: Session object pointer.
237  *
238  * The caller must have zero-initialized @se_sess before calling this function.
239  */
240 int transport_init_session(struct se_session *se_sess)
241 {
242 	INIT_LIST_HEAD(&se_sess->sess_list);
243 	INIT_LIST_HEAD(&se_sess->sess_acl_list);
244 	INIT_LIST_HEAD(&se_sess->sess_cmd_list);
245 	spin_lock_init(&se_sess->sess_cmd_lock);
246 	init_waitqueue_head(&se_sess->cmd_list_wq);
247 	return percpu_ref_init(&se_sess->cmd_count,
248 			       target_release_sess_cmd_refcnt, 0, GFP_KERNEL);
249 }
250 EXPORT_SYMBOL(transport_init_session);
251 
252 /**
253  * transport_alloc_session - allocate a session object and initialize it
254  * @sup_prot_ops: bitmask that defines which T10-PI modes are supported.
255  */
256 struct se_session *transport_alloc_session(enum target_prot_op sup_prot_ops)
257 {
258 	struct se_session *se_sess;
259 	int ret;
260 
261 	se_sess = kmem_cache_zalloc(se_sess_cache, GFP_KERNEL);
262 	if (!se_sess) {
263 		pr_err("Unable to allocate struct se_session from"
264 				" se_sess_cache\n");
265 		return ERR_PTR(-ENOMEM);
266 	}
267 	ret = transport_init_session(se_sess);
268 	if (ret < 0) {
269 		kmem_cache_free(se_sess_cache, se_sess);
270 		return ERR_PTR(ret);
271 	}
272 	se_sess->sup_prot_ops = sup_prot_ops;
273 
274 	return se_sess;
275 }
276 EXPORT_SYMBOL(transport_alloc_session);
277 
278 /**
279  * transport_alloc_session_tags - allocate target driver private data
280  * @se_sess:  Session pointer.
281  * @tag_num:  Maximum number of in-flight commands between initiator and target.
282  * @tag_size: Size in bytes of the private data a target driver associates with
283  *	      each command.
284  */
285 int transport_alloc_session_tags(struct se_session *se_sess,
286 			         unsigned int tag_num, unsigned int tag_size)
287 {
288 	int rc;
289 
290 	se_sess->sess_cmd_map = kvcalloc(tag_size, tag_num,
291 					 GFP_KERNEL | __GFP_RETRY_MAYFAIL);
292 	if (!se_sess->sess_cmd_map) {
293 		pr_err("Unable to allocate se_sess->sess_cmd_map\n");
294 		return -ENOMEM;
295 	}
296 
297 	rc = sbitmap_queue_init_node(&se_sess->sess_tag_pool, tag_num, -1,
298 			false, GFP_KERNEL, NUMA_NO_NODE);
299 	if (rc < 0) {
300 		pr_err("Unable to init se_sess->sess_tag_pool,"
301 			" tag_num: %u\n", tag_num);
302 		kvfree(se_sess->sess_cmd_map);
303 		se_sess->sess_cmd_map = NULL;
304 		return -ENOMEM;
305 	}
306 
307 	return 0;
308 }
309 EXPORT_SYMBOL(transport_alloc_session_tags);
310 
311 /**
312  * transport_init_session_tags - allocate a session and target driver private data
313  * @tag_num:  Maximum number of in-flight commands between initiator and target.
314  * @tag_size: Size in bytes of the private data a target driver associates with
315  *	      each command.
316  * @sup_prot_ops: bitmask that defines which T10-PI modes are supported.
317  */
318 static struct se_session *
319 transport_init_session_tags(unsigned int tag_num, unsigned int tag_size,
320 			    enum target_prot_op sup_prot_ops)
321 {
322 	struct se_session *se_sess;
323 	int rc;
324 
325 	if (tag_num != 0 && !tag_size) {
326 		pr_err("init_session_tags called with percpu-ida tag_num:"
327 		       " %u, but zero tag_size\n", tag_num);
328 		return ERR_PTR(-EINVAL);
329 	}
330 	if (!tag_num && tag_size) {
331 		pr_err("init_session_tags called with percpu-ida tag_size:"
332 		       " %u, but zero tag_num\n", tag_size);
333 		return ERR_PTR(-EINVAL);
334 	}
335 
336 	se_sess = transport_alloc_session(sup_prot_ops);
337 	if (IS_ERR(se_sess))
338 		return se_sess;
339 
340 	rc = transport_alloc_session_tags(se_sess, tag_num, tag_size);
341 	if (rc < 0) {
342 		transport_free_session(se_sess);
343 		return ERR_PTR(-ENOMEM);
344 	}
345 
346 	return se_sess;
347 }
348 
349 /*
350  * Called with spin_lock_irqsave(&struct se_portal_group->session_lock called.
351  */
352 void __transport_register_session(
353 	struct se_portal_group *se_tpg,
354 	struct se_node_acl *se_nacl,
355 	struct se_session *se_sess,
356 	void *fabric_sess_ptr)
357 {
358 	const struct target_core_fabric_ops *tfo = se_tpg->se_tpg_tfo;
359 	unsigned char buf[PR_REG_ISID_LEN];
360 	unsigned long flags;
361 
362 	se_sess->se_tpg = se_tpg;
363 	se_sess->fabric_sess_ptr = fabric_sess_ptr;
364 	/*
365 	 * Used by struct se_node_acl's under ConfigFS to locate active se_session-t
366 	 *
367 	 * Only set for struct se_session's that will actually be moving I/O.
368 	 * eg: *NOT* discovery sessions.
369 	 */
370 	if (se_nacl) {
371 		/*
372 		 *
373 		 * Determine if fabric allows for T10-PI feature bits exposed to
374 		 * initiators for device backends with !dev->dev_attrib.pi_prot_type.
375 		 *
376 		 * If so, then always save prot_type on a per se_node_acl node
377 		 * basis and re-instate the previous sess_prot_type to avoid
378 		 * disabling PI from below any previously initiator side
379 		 * registered LUNs.
380 		 */
381 		if (se_nacl->saved_prot_type)
382 			se_sess->sess_prot_type = se_nacl->saved_prot_type;
383 		else if (tfo->tpg_check_prot_fabric_only)
384 			se_sess->sess_prot_type = se_nacl->saved_prot_type =
385 					tfo->tpg_check_prot_fabric_only(se_tpg);
386 		/*
387 		 * If the fabric module supports an ISID based TransportID,
388 		 * save this value in binary from the fabric I_T Nexus now.
389 		 */
390 		if (se_tpg->se_tpg_tfo->sess_get_initiator_sid != NULL) {
391 			memset(&buf[0], 0, PR_REG_ISID_LEN);
392 			se_tpg->se_tpg_tfo->sess_get_initiator_sid(se_sess,
393 					&buf[0], PR_REG_ISID_LEN);
394 			se_sess->sess_bin_isid = get_unaligned_be64(&buf[0]);
395 		}
396 
397 		spin_lock_irqsave(&se_nacl->nacl_sess_lock, flags);
398 		/*
399 		 * The se_nacl->nacl_sess pointer will be set to the
400 		 * last active I_T Nexus for each struct se_node_acl.
401 		 */
402 		se_nacl->nacl_sess = se_sess;
403 
404 		list_add_tail(&se_sess->sess_acl_list,
405 			      &se_nacl->acl_sess_list);
406 		spin_unlock_irqrestore(&se_nacl->nacl_sess_lock, flags);
407 	}
408 	list_add_tail(&se_sess->sess_list, &se_tpg->tpg_sess_list);
409 
410 	pr_debug("TARGET_CORE[%s]: Registered fabric_sess_ptr: %p\n",
411 		se_tpg->se_tpg_tfo->fabric_name, se_sess->fabric_sess_ptr);
412 }
413 EXPORT_SYMBOL(__transport_register_session);
414 
415 void transport_register_session(
416 	struct se_portal_group *se_tpg,
417 	struct se_node_acl *se_nacl,
418 	struct se_session *se_sess,
419 	void *fabric_sess_ptr)
420 {
421 	unsigned long flags;
422 
423 	spin_lock_irqsave(&se_tpg->session_lock, flags);
424 	__transport_register_session(se_tpg, se_nacl, se_sess, fabric_sess_ptr);
425 	spin_unlock_irqrestore(&se_tpg->session_lock, flags);
426 }
427 EXPORT_SYMBOL(transport_register_session);
428 
429 struct se_session *
430 target_setup_session(struct se_portal_group *tpg,
431 		     unsigned int tag_num, unsigned int tag_size,
432 		     enum target_prot_op prot_op,
433 		     const char *initiatorname, void *private,
434 		     int (*callback)(struct se_portal_group *,
435 				     struct se_session *, void *))
436 {
437 	struct se_session *sess;
438 
439 	/*
440 	 * If the fabric driver is using percpu-ida based pre allocation
441 	 * of I/O descriptor tags, go ahead and perform that setup now..
442 	 */
443 	if (tag_num != 0)
444 		sess = transport_init_session_tags(tag_num, tag_size, prot_op);
445 	else
446 		sess = transport_alloc_session(prot_op);
447 
448 	if (IS_ERR(sess))
449 		return sess;
450 
451 	sess->se_node_acl = core_tpg_check_initiator_node_acl(tpg,
452 					(unsigned char *)initiatorname);
453 	if (!sess->se_node_acl) {
454 		transport_free_session(sess);
455 		return ERR_PTR(-EACCES);
456 	}
457 	/*
458 	 * Go ahead and perform any remaining fabric setup that is
459 	 * required before transport_register_session().
460 	 */
461 	if (callback != NULL) {
462 		int rc = callback(tpg, sess, private);
463 		if (rc) {
464 			transport_free_session(sess);
465 			return ERR_PTR(rc);
466 		}
467 	}
468 
469 	transport_register_session(tpg, sess->se_node_acl, sess, private);
470 	return sess;
471 }
472 EXPORT_SYMBOL(target_setup_session);
473 
474 ssize_t target_show_dynamic_sessions(struct se_portal_group *se_tpg, char *page)
475 {
476 	struct se_session *se_sess;
477 	ssize_t len = 0;
478 
479 	spin_lock_bh(&se_tpg->session_lock);
480 	list_for_each_entry(se_sess, &se_tpg->tpg_sess_list, sess_list) {
481 		if (!se_sess->se_node_acl)
482 			continue;
483 		if (!se_sess->se_node_acl->dynamic_node_acl)
484 			continue;
485 		if (strlen(se_sess->se_node_acl->initiatorname) + 1 + len > PAGE_SIZE)
486 			break;
487 
488 		len += snprintf(page + len, PAGE_SIZE - len, "%s\n",
489 				se_sess->se_node_acl->initiatorname);
490 		len += 1; /* Include NULL terminator */
491 	}
492 	spin_unlock_bh(&se_tpg->session_lock);
493 
494 	return len;
495 }
496 EXPORT_SYMBOL(target_show_dynamic_sessions);
497 
498 static void target_complete_nacl(struct kref *kref)
499 {
500 	struct se_node_acl *nacl = container_of(kref,
501 				struct se_node_acl, acl_kref);
502 	struct se_portal_group *se_tpg = nacl->se_tpg;
503 
504 	if (!nacl->dynamic_stop) {
505 		complete(&nacl->acl_free_comp);
506 		return;
507 	}
508 
509 	mutex_lock(&se_tpg->acl_node_mutex);
510 	list_del_init(&nacl->acl_list);
511 	mutex_unlock(&se_tpg->acl_node_mutex);
512 
513 	core_tpg_wait_for_nacl_pr_ref(nacl);
514 	core_free_device_list_for_node(nacl, se_tpg);
515 	kfree(nacl);
516 }
517 
518 void target_put_nacl(struct se_node_acl *nacl)
519 {
520 	kref_put(&nacl->acl_kref, target_complete_nacl);
521 }
522 EXPORT_SYMBOL(target_put_nacl);
523 
524 void transport_deregister_session_configfs(struct se_session *se_sess)
525 {
526 	struct se_node_acl *se_nacl;
527 	unsigned long flags;
528 	/*
529 	 * Used by struct se_node_acl's under ConfigFS to locate active struct se_session
530 	 */
531 	se_nacl = se_sess->se_node_acl;
532 	if (se_nacl) {
533 		spin_lock_irqsave(&se_nacl->nacl_sess_lock, flags);
534 		if (!list_empty(&se_sess->sess_acl_list))
535 			list_del_init(&se_sess->sess_acl_list);
536 		/*
537 		 * If the session list is empty, then clear the pointer.
538 		 * Otherwise, set the struct se_session pointer from the tail
539 		 * element of the per struct se_node_acl active session list.
540 		 */
541 		if (list_empty(&se_nacl->acl_sess_list))
542 			se_nacl->nacl_sess = NULL;
543 		else {
544 			se_nacl->nacl_sess = container_of(
545 					se_nacl->acl_sess_list.prev,
546 					struct se_session, sess_acl_list);
547 		}
548 		spin_unlock_irqrestore(&se_nacl->nacl_sess_lock, flags);
549 	}
550 }
551 EXPORT_SYMBOL(transport_deregister_session_configfs);
552 
553 void transport_free_session(struct se_session *se_sess)
554 {
555 	struct se_node_acl *se_nacl = se_sess->se_node_acl;
556 
557 	/*
558 	 * Drop the se_node_acl->nacl_kref obtained from within
559 	 * core_tpg_get_initiator_node_acl().
560 	 */
561 	if (se_nacl) {
562 		struct se_portal_group *se_tpg = se_nacl->se_tpg;
563 		const struct target_core_fabric_ops *se_tfo = se_tpg->se_tpg_tfo;
564 		unsigned long flags;
565 
566 		se_sess->se_node_acl = NULL;
567 
568 		/*
569 		 * Also determine if we need to drop the extra ->cmd_kref if
570 		 * it had been previously dynamically generated, and
571 		 * the endpoint is not caching dynamic ACLs.
572 		 */
573 		mutex_lock(&se_tpg->acl_node_mutex);
574 		if (se_nacl->dynamic_node_acl &&
575 		    !se_tfo->tpg_check_demo_mode_cache(se_tpg)) {
576 			spin_lock_irqsave(&se_nacl->nacl_sess_lock, flags);
577 			if (list_empty(&se_nacl->acl_sess_list))
578 				se_nacl->dynamic_stop = true;
579 			spin_unlock_irqrestore(&se_nacl->nacl_sess_lock, flags);
580 
581 			if (se_nacl->dynamic_stop)
582 				list_del_init(&se_nacl->acl_list);
583 		}
584 		mutex_unlock(&se_tpg->acl_node_mutex);
585 
586 		if (se_nacl->dynamic_stop)
587 			target_put_nacl(se_nacl);
588 
589 		target_put_nacl(se_nacl);
590 	}
591 	if (se_sess->sess_cmd_map) {
592 		sbitmap_queue_free(&se_sess->sess_tag_pool);
593 		kvfree(se_sess->sess_cmd_map);
594 	}
595 	percpu_ref_exit(&se_sess->cmd_count);
596 	kmem_cache_free(se_sess_cache, se_sess);
597 }
598 EXPORT_SYMBOL(transport_free_session);
599 
600 void transport_deregister_session(struct se_session *se_sess)
601 {
602 	struct se_portal_group *se_tpg = se_sess->se_tpg;
603 	unsigned long flags;
604 
605 	if (!se_tpg) {
606 		transport_free_session(se_sess);
607 		return;
608 	}
609 
610 	spin_lock_irqsave(&se_tpg->session_lock, flags);
611 	list_del(&se_sess->sess_list);
612 	se_sess->se_tpg = NULL;
613 	se_sess->fabric_sess_ptr = NULL;
614 	spin_unlock_irqrestore(&se_tpg->session_lock, flags);
615 
616 	pr_debug("TARGET_CORE[%s]: Deregistered fabric_sess\n",
617 		se_tpg->se_tpg_tfo->fabric_name);
618 	/*
619 	 * If last kref is dropping now for an explicit NodeACL, awake sleeping
620 	 * ->acl_free_comp caller to wakeup configfs se_node_acl->acl_group
621 	 * removal context from within transport_free_session() code.
622 	 *
623 	 * For dynamic ACL, target_put_nacl() uses target_complete_nacl()
624 	 * to release all remaining generate_node_acl=1 created ACL resources.
625 	 */
626 
627 	transport_free_session(se_sess);
628 }
629 EXPORT_SYMBOL(transport_deregister_session);
630 
631 void target_remove_session(struct se_session *se_sess)
632 {
633 	transport_deregister_session_configfs(se_sess);
634 	transport_deregister_session(se_sess);
635 }
636 EXPORT_SYMBOL(target_remove_session);
637 
638 static void target_remove_from_state_list(struct se_cmd *cmd)
639 {
640 	struct se_device *dev = cmd->se_dev;
641 	unsigned long flags;
642 
643 	if (!dev)
644 		return;
645 
646 	spin_lock_irqsave(&dev->execute_task_lock, flags);
647 	if (cmd->state_active) {
648 		list_del(&cmd->state_list);
649 		cmd->state_active = false;
650 	}
651 	spin_unlock_irqrestore(&dev->execute_task_lock, flags);
652 }
653 
654 /*
655  * This function is called by the target core after the target core has
656  * finished processing a SCSI command or SCSI TMF. Both the regular command
657  * processing code and the code for aborting commands can call this
658  * function. CMD_T_STOP is set if and only if another thread is waiting
659  * inside transport_wait_for_tasks() for t_transport_stop_comp.
660  */
661 static int transport_cmd_check_stop_to_fabric(struct se_cmd *cmd)
662 {
663 	unsigned long flags;
664 
665 	target_remove_from_state_list(cmd);
666 
667 	/*
668 	 * Clear struct se_cmd->se_lun before the handoff to FE.
669 	 */
670 	cmd->se_lun = NULL;
671 
672 	spin_lock_irqsave(&cmd->t_state_lock, flags);
673 	/*
674 	 * Determine if frontend context caller is requesting the stopping of
675 	 * this command for frontend exceptions.
676 	 */
677 	if (cmd->transport_state & CMD_T_STOP) {
678 		pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08llx\n",
679 			__func__, __LINE__, cmd->tag);
680 
681 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
682 
683 		complete_all(&cmd->t_transport_stop_comp);
684 		return 1;
685 	}
686 	cmd->transport_state &= ~CMD_T_ACTIVE;
687 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
688 
689 	/*
690 	 * Some fabric modules like tcm_loop can release their internally
691 	 * allocated I/O reference and struct se_cmd now.
692 	 *
693 	 * Fabric modules are expected to return '1' here if the se_cmd being
694 	 * passed is released at this point, or zero if not being released.
695 	 */
696 	return cmd->se_tfo->check_stop_free(cmd);
697 }
698 
699 static void transport_lun_remove_cmd(struct se_cmd *cmd)
700 {
701 	struct se_lun *lun = cmd->se_lun;
702 
703 	if (!lun)
704 		return;
705 
706 	if (cmpxchg(&cmd->lun_ref_active, true, false))
707 		percpu_ref_put(&lun->lun_ref);
708 }
709 
710 static void target_complete_failure_work(struct work_struct *work)
711 {
712 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
713 
714 	transport_generic_request_failure(cmd,
715 			TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE);
716 }
717 
718 /*
719  * Used when asking transport to copy Sense Data from the underlying
720  * Linux/SCSI struct scsi_cmnd
721  */
722 static unsigned char *transport_get_sense_buffer(struct se_cmd *cmd)
723 {
724 	struct se_device *dev = cmd->se_dev;
725 
726 	WARN_ON(!cmd->se_lun);
727 
728 	if (!dev)
729 		return NULL;
730 
731 	if (cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION)
732 		return NULL;
733 
734 	cmd->scsi_sense_length = TRANSPORT_SENSE_BUFFER;
735 
736 	pr_debug("HBA_[%u]_PLUG[%s]: Requesting sense for SAM STATUS: 0x%02x\n",
737 		dev->se_hba->hba_id, dev->transport->name, cmd->scsi_status);
738 	return cmd->sense_buffer;
739 }
740 
741 void transport_copy_sense_to_cmd(struct se_cmd *cmd, unsigned char *sense)
742 {
743 	unsigned char *cmd_sense_buf;
744 	unsigned long flags;
745 
746 	spin_lock_irqsave(&cmd->t_state_lock, flags);
747 	cmd_sense_buf = transport_get_sense_buffer(cmd);
748 	if (!cmd_sense_buf) {
749 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
750 		return;
751 	}
752 
753 	cmd->se_cmd_flags |= SCF_TRANSPORT_TASK_SENSE;
754 	memcpy(cmd_sense_buf, sense, cmd->scsi_sense_length);
755 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
756 }
757 EXPORT_SYMBOL(transport_copy_sense_to_cmd);
758 
759 static void target_handle_abort(struct se_cmd *cmd)
760 {
761 	bool tas = cmd->transport_state & CMD_T_TAS;
762 	bool ack_kref = cmd->se_cmd_flags & SCF_ACK_KREF;
763 	int ret;
764 
765 	pr_debug("tag %#llx: send_abort_response = %d\n", cmd->tag, tas);
766 
767 	if (tas) {
768 		if (!(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)) {
769 			cmd->scsi_status = SAM_STAT_TASK_ABORTED;
770 			pr_debug("Setting SAM_STAT_TASK_ABORTED status for CDB: 0x%02x, ITT: 0x%08llx\n",
771 				 cmd->t_task_cdb[0], cmd->tag);
772 			trace_target_cmd_complete(cmd);
773 			ret = cmd->se_tfo->queue_status(cmd);
774 			if (ret) {
775 				transport_handle_queue_full(cmd, cmd->se_dev,
776 							    ret, false);
777 				return;
778 			}
779 		} else {
780 			cmd->se_tmr_req->response = TMR_FUNCTION_REJECTED;
781 			cmd->se_tfo->queue_tm_rsp(cmd);
782 		}
783 	} else {
784 		/*
785 		 * Allow the fabric driver to unmap any resources before
786 		 * releasing the descriptor via TFO->release_cmd().
787 		 */
788 		cmd->se_tfo->aborted_task(cmd);
789 		if (ack_kref)
790 			WARN_ON_ONCE(target_put_sess_cmd(cmd) != 0);
791 		/*
792 		 * To do: establish a unit attention condition on the I_T
793 		 * nexus associated with cmd. See also the paragraph "Aborting
794 		 * commands" in SAM.
795 		 */
796 	}
797 
798 	WARN_ON_ONCE(kref_read(&cmd->cmd_kref) == 0);
799 
800 	transport_lun_remove_cmd(cmd);
801 
802 	transport_cmd_check_stop_to_fabric(cmd);
803 }
804 
805 static void target_abort_work(struct work_struct *work)
806 {
807 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
808 
809 	target_handle_abort(cmd);
810 }
811 
812 static bool target_cmd_interrupted(struct se_cmd *cmd)
813 {
814 	int post_ret;
815 
816 	if (cmd->transport_state & CMD_T_ABORTED) {
817 		if (cmd->transport_complete_callback)
818 			cmd->transport_complete_callback(cmd, false, &post_ret);
819 		INIT_WORK(&cmd->work, target_abort_work);
820 		queue_work(target_completion_wq, &cmd->work);
821 		return true;
822 	} else if (cmd->transport_state & CMD_T_STOP) {
823 		if (cmd->transport_complete_callback)
824 			cmd->transport_complete_callback(cmd, false, &post_ret);
825 		complete_all(&cmd->t_transport_stop_comp);
826 		return true;
827 	}
828 
829 	return false;
830 }
831 
832 /* May be called from interrupt context so must not sleep. */
833 void target_complete_cmd(struct se_cmd *cmd, u8 scsi_status)
834 {
835 	int success;
836 	unsigned long flags;
837 
838 	if (target_cmd_interrupted(cmd))
839 		return;
840 
841 	cmd->scsi_status = scsi_status;
842 
843 	spin_lock_irqsave(&cmd->t_state_lock, flags);
844 	switch (cmd->scsi_status) {
845 	case SAM_STAT_CHECK_CONDITION:
846 		if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE)
847 			success = 1;
848 		else
849 			success = 0;
850 		break;
851 	default:
852 		success = 1;
853 		break;
854 	}
855 
856 	cmd->t_state = TRANSPORT_COMPLETE;
857 	cmd->transport_state |= (CMD_T_COMPLETE | CMD_T_ACTIVE);
858 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
859 
860 	INIT_WORK(&cmd->work, success ? target_complete_ok_work :
861 		  target_complete_failure_work);
862 	if (cmd->se_cmd_flags & SCF_USE_CPUID)
863 		queue_work_on(cmd->cpuid, target_completion_wq, &cmd->work);
864 	else
865 		queue_work(target_completion_wq, &cmd->work);
866 }
867 EXPORT_SYMBOL(target_complete_cmd);
868 
869 void target_complete_cmd_with_length(struct se_cmd *cmd, u8 scsi_status, int length)
870 {
871 	if ((scsi_status == SAM_STAT_GOOD ||
872 	     cmd->se_cmd_flags & SCF_TREAT_READ_AS_NORMAL) &&
873 	    length < cmd->data_length) {
874 		if (cmd->se_cmd_flags & SCF_UNDERFLOW_BIT) {
875 			cmd->residual_count += cmd->data_length - length;
876 		} else {
877 			cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
878 			cmd->residual_count = cmd->data_length - length;
879 		}
880 
881 		cmd->data_length = length;
882 	}
883 
884 	target_complete_cmd(cmd, scsi_status);
885 }
886 EXPORT_SYMBOL(target_complete_cmd_with_length);
887 
888 static void target_add_to_state_list(struct se_cmd *cmd)
889 {
890 	struct se_device *dev = cmd->se_dev;
891 	unsigned long flags;
892 
893 	spin_lock_irqsave(&dev->execute_task_lock, flags);
894 	if (!cmd->state_active) {
895 		list_add_tail(&cmd->state_list, &dev->state_list);
896 		cmd->state_active = true;
897 	}
898 	spin_unlock_irqrestore(&dev->execute_task_lock, flags);
899 }
900 
901 /*
902  * Handle QUEUE_FULL / -EAGAIN and -ENOMEM status
903  */
904 static void transport_write_pending_qf(struct se_cmd *cmd);
905 static void transport_complete_qf(struct se_cmd *cmd);
906 
907 void target_qf_do_work(struct work_struct *work)
908 {
909 	struct se_device *dev = container_of(work, struct se_device,
910 					qf_work_queue);
911 	LIST_HEAD(qf_cmd_list);
912 	struct se_cmd *cmd, *cmd_tmp;
913 
914 	spin_lock_irq(&dev->qf_cmd_lock);
915 	list_splice_init(&dev->qf_cmd_list, &qf_cmd_list);
916 	spin_unlock_irq(&dev->qf_cmd_lock);
917 
918 	list_for_each_entry_safe(cmd, cmd_tmp, &qf_cmd_list, se_qf_node) {
919 		list_del(&cmd->se_qf_node);
920 		atomic_dec_mb(&dev->dev_qf_count);
921 
922 		pr_debug("Processing %s cmd: %p QUEUE_FULL in work queue"
923 			" context: %s\n", cmd->se_tfo->fabric_name, cmd,
924 			(cmd->t_state == TRANSPORT_COMPLETE_QF_OK) ? "COMPLETE_OK" :
925 			(cmd->t_state == TRANSPORT_COMPLETE_QF_WP) ? "WRITE_PENDING"
926 			: "UNKNOWN");
927 
928 		if (cmd->t_state == TRANSPORT_COMPLETE_QF_WP)
929 			transport_write_pending_qf(cmd);
930 		else if (cmd->t_state == TRANSPORT_COMPLETE_QF_OK ||
931 			 cmd->t_state == TRANSPORT_COMPLETE_QF_ERR)
932 			transport_complete_qf(cmd);
933 	}
934 }
935 
936 unsigned char *transport_dump_cmd_direction(struct se_cmd *cmd)
937 {
938 	switch (cmd->data_direction) {
939 	case DMA_NONE:
940 		return "NONE";
941 	case DMA_FROM_DEVICE:
942 		return "READ";
943 	case DMA_TO_DEVICE:
944 		return "WRITE";
945 	case DMA_BIDIRECTIONAL:
946 		return "BIDI";
947 	default:
948 		break;
949 	}
950 
951 	return "UNKNOWN";
952 }
953 
954 void transport_dump_dev_state(
955 	struct se_device *dev,
956 	char *b,
957 	int *bl)
958 {
959 	*bl += sprintf(b + *bl, "Status: ");
960 	if (dev->export_count)
961 		*bl += sprintf(b + *bl, "ACTIVATED");
962 	else
963 		*bl += sprintf(b + *bl, "DEACTIVATED");
964 
965 	*bl += sprintf(b + *bl, "  Max Queue Depth: %d", dev->queue_depth);
966 	*bl += sprintf(b + *bl, "  SectorSize: %u  HwMaxSectors: %u\n",
967 		dev->dev_attrib.block_size,
968 		dev->dev_attrib.hw_max_sectors);
969 	*bl += sprintf(b + *bl, "        ");
970 }
971 
972 void transport_dump_vpd_proto_id(
973 	struct t10_vpd *vpd,
974 	unsigned char *p_buf,
975 	int p_buf_len)
976 {
977 	unsigned char buf[VPD_TMP_BUF_SIZE];
978 	int len;
979 
980 	memset(buf, 0, VPD_TMP_BUF_SIZE);
981 	len = sprintf(buf, "T10 VPD Protocol Identifier: ");
982 
983 	switch (vpd->protocol_identifier) {
984 	case 0x00:
985 		sprintf(buf+len, "Fibre Channel\n");
986 		break;
987 	case 0x10:
988 		sprintf(buf+len, "Parallel SCSI\n");
989 		break;
990 	case 0x20:
991 		sprintf(buf+len, "SSA\n");
992 		break;
993 	case 0x30:
994 		sprintf(buf+len, "IEEE 1394\n");
995 		break;
996 	case 0x40:
997 		sprintf(buf+len, "SCSI Remote Direct Memory Access"
998 				" Protocol\n");
999 		break;
1000 	case 0x50:
1001 		sprintf(buf+len, "Internet SCSI (iSCSI)\n");
1002 		break;
1003 	case 0x60:
1004 		sprintf(buf+len, "SAS Serial SCSI Protocol\n");
1005 		break;
1006 	case 0x70:
1007 		sprintf(buf+len, "Automation/Drive Interface Transport"
1008 				" Protocol\n");
1009 		break;
1010 	case 0x80:
1011 		sprintf(buf+len, "AT Attachment Interface ATA/ATAPI\n");
1012 		break;
1013 	default:
1014 		sprintf(buf+len, "Unknown 0x%02x\n",
1015 				vpd->protocol_identifier);
1016 		break;
1017 	}
1018 
1019 	if (p_buf)
1020 		strncpy(p_buf, buf, p_buf_len);
1021 	else
1022 		pr_debug("%s", buf);
1023 }
1024 
1025 void
1026 transport_set_vpd_proto_id(struct t10_vpd *vpd, unsigned char *page_83)
1027 {
1028 	/*
1029 	 * Check if the Protocol Identifier Valid (PIV) bit is set..
1030 	 *
1031 	 * from spc3r23.pdf section 7.5.1
1032 	 */
1033 	 if (page_83[1] & 0x80) {
1034 		vpd->protocol_identifier = (page_83[0] & 0xf0);
1035 		vpd->protocol_identifier_set = 1;
1036 		transport_dump_vpd_proto_id(vpd, NULL, 0);
1037 	}
1038 }
1039 EXPORT_SYMBOL(transport_set_vpd_proto_id);
1040 
1041 int transport_dump_vpd_assoc(
1042 	struct t10_vpd *vpd,
1043 	unsigned char *p_buf,
1044 	int p_buf_len)
1045 {
1046 	unsigned char buf[VPD_TMP_BUF_SIZE];
1047 	int ret = 0;
1048 	int len;
1049 
1050 	memset(buf, 0, VPD_TMP_BUF_SIZE);
1051 	len = sprintf(buf, "T10 VPD Identifier Association: ");
1052 
1053 	switch (vpd->association) {
1054 	case 0x00:
1055 		sprintf(buf+len, "addressed logical unit\n");
1056 		break;
1057 	case 0x10:
1058 		sprintf(buf+len, "target port\n");
1059 		break;
1060 	case 0x20:
1061 		sprintf(buf+len, "SCSI target device\n");
1062 		break;
1063 	default:
1064 		sprintf(buf+len, "Unknown 0x%02x\n", vpd->association);
1065 		ret = -EINVAL;
1066 		break;
1067 	}
1068 
1069 	if (p_buf)
1070 		strncpy(p_buf, buf, p_buf_len);
1071 	else
1072 		pr_debug("%s", buf);
1073 
1074 	return ret;
1075 }
1076 
1077 int transport_set_vpd_assoc(struct t10_vpd *vpd, unsigned char *page_83)
1078 {
1079 	/*
1080 	 * The VPD identification association..
1081 	 *
1082 	 * from spc3r23.pdf Section 7.6.3.1 Table 297
1083 	 */
1084 	vpd->association = (page_83[1] & 0x30);
1085 	return transport_dump_vpd_assoc(vpd, NULL, 0);
1086 }
1087 EXPORT_SYMBOL(transport_set_vpd_assoc);
1088 
1089 int transport_dump_vpd_ident_type(
1090 	struct t10_vpd *vpd,
1091 	unsigned char *p_buf,
1092 	int p_buf_len)
1093 {
1094 	unsigned char buf[VPD_TMP_BUF_SIZE];
1095 	int ret = 0;
1096 	int len;
1097 
1098 	memset(buf, 0, VPD_TMP_BUF_SIZE);
1099 	len = sprintf(buf, "T10 VPD Identifier Type: ");
1100 
1101 	switch (vpd->device_identifier_type) {
1102 	case 0x00:
1103 		sprintf(buf+len, "Vendor specific\n");
1104 		break;
1105 	case 0x01:
1106 		sprintf(buf+len, "T10 Vendor ID based\n");
1107 		break;
1108 	case 0x02:
1109 		sprintf(buf+len, "EUI-64 based\n");
1110 		break;
1111 	case 0x03:
1112 		sprintf(buf+len, "NAA\n");
1113 		break;
1114 	case 0x04:
1115 		sprintf(buf+len, "Relative target port identifier\n");
1116 		break;
1117 	case 0x08:
1118 		sprintf(buf+len, "SCSI name string\n");
1119 		break;
1120 	default:
1121 		sprintf(buf+len, "Unsupported: 0x%02x\n",
1122 				vpd->device_identifier_type);
1123 		ret = -EINVAL;
1124 		break;
1125 	}
1126 
1127 	if (p_buf) {
1128 		if (p_buf_len < strlen(buf)+1)
1129 			return -EINVAL;
1130 		strncpy(p_buf, buf, p_buf_len);
1131 	} else {
1132 		pr_debug("%s", buf);
1133 	}
1134 
1135 	return ret;
1136 }
1137 
1138 int transport_set_vpd_ident_type(struct t10_vpd *vpd, unsigned char *page_83)
1139 {
1140 	/*
1141 	 * The VPD identifier type..
1142 	 *
1143 	 * from spc3r23.pdf Section 7.6.3.1 Table 298
1144 	 */
1145 	vpd->device_identifier_type = (page_83[1] & 0x0f);
1146 	return transport_dump_vpd_ident_type(vpd, NULL, 0);
1147 }
1148 EXPORT_SYMBOL(transport_set_vpd_ident_type);
1149 
1150 int transport_dump_vpd_ident(
1151 	struct t10_vpd *vpd,
1152 	unsigned char *p_buf,
1153 	int p_buf_len)
1154 {
1155 	unsigned char buf[VPD_TMP_BUF_SIZE];
1156 	int ret = 0;
1157 
1158 	memset(buf, 0, VPD_TMP_BUF_SIZE);
1159 
1160 	switch (vpd->device_identifier_code_set) {
1161 	case 0x01: /* Binary */
1162 		snprintf(buf, sizeof(buf),
1163 			"T10 VPD Binary Device Identifier: %s\n",
1164 			&vpd->device_identifier[0]);
1165 		break;
1166 	case 0x02: /* ASCII */
1167 		snprintf(buf, sizeof(buf),
1168 			"T10 VPD ASCII Device Identifier: %s\n",
1169 			&vpd->device_identifier[0]);
1170 		break;
1171 	case 0x03: /* UTF-8 */
1172 		snprintf(buf, sizeof(buf),
1173 			"T10 VPD UTF-8 Device Identifier: %s\n",
1174 			&vpd->device_identifier[0]);
1175 		break;
1176 	default:
1177 		sprintf(buf, "T10 VPD Device Identifier encoding unsupported:"
1178 			" 0x%02x", vpd->device_identifier_code_set);
1179 		ret = -EINVAL;
1180 		break;
1181 	}
1182 
1183 	if (p_buf)
1184 		strncpy(p_buf, buf, p_buf_len);
1185 	else
1186 		pr_debug("%s", buf);
1187 
1188 	return ret;
1189 }
1190 
1191 int
1192 transport_set_vpd_ident(struct t10_vpd *vpd, unsigned char *page_83)
1193 {
1194 	static const char hex_str[] = "0123456789abcdef";
1195 	int j = 0, i = 4; /* offset to start of the identifier */
1196 
1197 	/*
1198 	 * The VPD Code Set (encoding)
1199 	 *
1200 	 * from spc3r23.pdf Section 7.6.3.1 Table 296
1201 	 */
1202 	vpd->device_identifier_code_set = (page_83[0] & 0x0f);
1203 	switch (vpd->device_identifier_code_set) {
1204 	case 0x01: /* Binary */
1205 		vpd->device_identifier[j++] =
1206 				hex_str[vpd->device_identifier_type];
1207 		while (i < (4 + page_83[3])) {
1208 			vpd->device_identifier[j++] =
1209 				hex_str[(page_83[i] & 0xf0) >> 4];
1210 			vpd->device_identifier[j++] =
1211 				hex_str[page_83[i] & 0x0f];
1212 			i++;
1213 		}
1214 		break;
1215 	case 0x02: /* ASCII */
1216 	case 0x03: /* UTF-8 */
1217 		while (i < (4 + page_83[3]))
1218 			vpd->device_identifier[j++] = page_83[i++];
1219 		break;
1220 	default:
1221 		break;
1222 	}
1223 
1224 	return transport_dump_vpd_ident(vpd, NULL, 0);
1225 }
1226 EXPORT_SYMBOL(transport_set_vpd_ident);
1227 
1228 static sense_reason_t
1229 target_check_max_data_sg_nents(struct se_cmd *cmd, struct se_device *dev,
1230 			       unsigned int size)
1231 {
1232 	u32 mtl;
1233 
1234 	if (!cmd->se_tfo->max_data_sg_nents)
1235 		return TCM_NO_SENSE;
1236 	/*
1237 	 * Check if fabric enforced maximum SGL entries per I/O descriptor
1238 	 * exceeds se_cmd->data_length.  If true, set SCF_UNDERFLOW_BIT +
1239 	 * residual_count and reduce original cmd->data_length to maximum
1240 	 * length based on single PAGE_SIZE entry scatter-lists.
1241 	 */
1242 	mtl = (cmd->se_tfo->max_data_sg_nents * PAGE_SIZE);
1243 	if (cmd->data_length > mtl) {
1244 		/*
1245 		 * If an existing CDB overflow is present, calculate new residual
1246 		 * based on CDB size minus fabric maximum transfer length.
1247 		 *
1248 		 * If an existing CDB underflow is present, calculate new residual
1249 		 * based on original cmd->data_length minus fabric maximum transfer
1250 		 * length.
1251 		 *
1252 		 * Otherwise, set the underflow residual based on cmd->data_length
1253 		 * minus fabric maximum transfer length.
1254 		 */
1255 		if (cmd->se_cmd_flags & SCF_OVERFLOW_BIT) {
1256 			cmd->residual_count = (size - mtl);
1257 		} else if (cmd->se_cmd_flags & SCF_UNDERFLOW_BIT) {
1258 			u32 orig_dl = size + cmd->residual_count;
1259 			cmd->residual_count = (orig_dl - mtl);
1260 		} else {
1261 			cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
1262 			cmd->residual_count = (cmd->data_length - mtl);
1263 		}
1264 		cmd->data_length = mtl;
1265 		/*
1266 		 * Reset sbc_check_prot() calculated protection payload
1267 		 * length based upon the new smaller MTL.
1268 		 */
1269 		if (cmd->prot_length) {
1270 			u32 sectors = (mtl / dev->dev_attrib.block_size);
1271 			cmd->prot_length = dev->prot_length * sectors;
1272 		}
1273 	}
1274 	return TCM_NO_SENSE;
1275 }
1276 
1277 sense_reason_t
1278 target_cmd_size_check(struct se_cmd *cmd, unsigned int size)
1279 {
1280 	struct se_device *dev = cmd->se_dev;
1281 
1282 	if (cmd->unknown_data_length) {
1283 		cmd->data_length = size;
1284 	} else if (size != cmd->data_length) {
1285 		pr_warn_ratelimited("TARGET_CORE[%s]: Expected Transfer Length:"
1286 			" %u does not match SCSI CDB Length: %u for SAM Opcode:"
1287 			" 0x%02x\n", cmd->se_tfo->fabric_name,
1288 				cmd->data_length, size, cmd->t_task_cdb[0]);
1289 
1290 		if (cmd->data_direction == DMA_TO_DEVICE) {
1291 			if (cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) {
1292 				pr_err_ratelimited("Rejecting underflow/overflow"
1293 						   " for WRITE data CDB\n");
1294 				return TCM_INVALID_CDB_FIELD;
1295 			}
1296 			/*
1297 			 * Some fabric drivers like iscsi-target still expect to
1298 			 * always reject overflow writes.  Reject this case until
1299 			 * full fabric driver level support for overflow writes
1300 			 * is introduced tree-wide.
1301 			 */
1302 			if (size > cmd->data_length) {
1303 				pr_err_ratelimited("Rejecting overflow for"
1304 						   " WRITE control CDB\n");
1305 				return TCM_INVALID_CDB_FIELD;
1306 			}
1307 		}
1308 		/*
1309 		 * Reject READ_* or WRITE_* with overflow/underflow for
1310 		 * type SCF_SCSI_DATA_CDB.
1311 		 */
1312 		if (dev->dev_attrib.block_size != 512)  {
1313 			pr_err("Failing OVERFLOW/UNDERFLOW for LBA op"
1314 				" CDB on non 512-byte sector setup subsystem"
1315 				" plugin: %s\n", dev->transport->name);
1316 			/* Returns CHECK_CONDITION + INVALID_CDB_FIELD */
1317 			return TCM_INVALID_CDB_FIELD;
1318 		}
1319 		/*
1320 		 * For the overflow case keep the existing fabric provided
1321 		 * ->data_length.  Otherwise for the underflow case, reset
1322 		 * ->data_length to the smaller SCSI expected data transfer
1323 		 * length.
1324 		 */
1325 		if (size > cmd->data_length) {
1326 			cmd->se_cmd_flags |= SCF_OVERFLOW_BIT;
1327 			cmd->residual_count = (size - cmd->data_length);
1328 		} else {
1329 			cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
1330 			cmd->residual_count = (cmd->data_length - size);
1331 			cmd->data_length = size;
1332 		}
1333 	}
1334 
1335 	return target_check_max_data_sg_nents(cmd, dev, size);
1336 
1337 }
1338 
1339 /*
1340  * Used by fabric modules containing a local struct se_cmd within their
1341  * fabric dependent per I/O descriptor.
1342  *
1343  * Preserves the value of @cmd->tag.
1344  */
1345 void transport_init_se_cmd(
1346 	struct se_cmd *cmd,
1347 	const struct target_core_fabric_ops *tfo,
1348 	struct se_session *se_sess,
1349 	u32 data_length,
1350 	int data_direction,
1351 	int task_attr,
1352 	unsigned char *sense_buffer)
1353 {
1354 	INIT_LIST_HEAD(&cmd->se_delayed_node);
1355 	INIT_LIST_HEAD(&cmd->se_qf_node);
1356 	INIT_LIST_HEAD(&cmd->se_cmd_list);
1357 	INIT_LIST_HEAD(&cmd->state_list);
1358 	init_completion(&cmd->t_transport_stop_comp);
1359 	cmd->free_compl = NULL;
1360 	cmd->abrt_compl = NULL;
1361 	spin_lock_init(&cmd->t_state_lock);
1362 	INIT_WORK(&cmd->work, NULL);
1363 	kref_init(&cmd->cmd_kref);
1364 
1365 	cmd->se_tfo = tfo;
1366 	cmd->se_sess = se_sess;
1367 	cmd->data_length = data_length;
1368 	cmd->data_direction = data_direction;
1369 	cmd->sam_task_attr = task_attr;
1370 	cmd->sense_buffer = sense_buffer;
1371 
1372 	cmd->state_active = false;
1373 }
1374 EXPORT_SYMBOL(transport_init_se_cmd);
1375 
1376 static sense_reason_t
1377 transport_check_alloc_task_attr(struct se_cmd *cmd)
1378 {
1379 	struct se_device *dev = cmd->se_dev;
1380 
1381 	/*
1382 	 * Check if SAM Task Attribute emulation is enabled for this
1383 	 * struct se_device storage object
1384 	 */
1385 	if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
1386 		return 0;
1387 
1388 	if (cmd->sam_task_attr == TCM_ACA_TAG) {
1389 		pr_debug("SAM Task Attribute ACA"
1390 			" emulation is not supported\n");
1391 		return TCM_INVALID_CDB_FIELD;
1392 	}
1393 
1394 	return 0;
1395 }
1396 
1397 sense_reason_t
1398 target_setup_cmd_from_cdb(struct se_cmd *cmd, unsigned char *cdb)
1399 {
1400 	struct se_device *dev = cmd->se_dev;
1401 	sense_reason_t ret;
1402 
1403 	/*
1404 	 * Ensure that the received CDB is less than the max (252 + 8) bytes
1405 	 * for VARIABLE_LENGTH_CMD
1406 	 */
1407 	if (scsi_command_size(cdb) > SCSI_MAX_VARLEN_CDB_SIZE) {
1408 		pr_err("Received SCSI CDB with command_size: %d that"
1409 			" exceeds SCSI_MAX_VARLEN_CDB_SIZE: %d\n",
1410 			scsi_command_size(cdb), SCSI_MAX_VARLEN_CDB_SIZE);
1411 		return TCM_INVALID_CDB_FIELD;
1412 	}
1413 	/*
1414 	 * If the received CDB is larger than TCM_MAX_COMMAND_SIZE,
1415 	 * allocate the additional extended CDB buffer now..  Otherwise
1416 	 * setup the pointer from __t_task_cdb to t_task_cdb.
1417 	 */
1418 	if (scsi_command_size(cdb) > sizeof(cmd->__t_task_cdb)) {
1419 		cmd->t_task_cdb = kzalloc(scsi_command_size(cdb),
1420 						GFP_KERNEL);
1421 		if (!cmd->t_task_cdb) {
1422 			pr_err("Unable to allocate cmd->t_task_cdb"
1423 				" %u > sizeof(cmd->__t_task_cdb): %lu ops\n",
1424 				scsi_command_size(cdb),
1425 				(unsigned long)sizeof(cmd->__t_task_cdb));
1426 			return TCM_OUT_OF_RESOURCES;
1427 		}
1428 	} else
1429 		cmd->t_task_cdb = &cmd->__t_task_cdb[0];
1430 	/*
1431 	 * Copy the original CDB into cmd->
1432 	 */
1433 	memcpy(cmd->t_task_cdb, cdb, scsi_command_size(cdb));
1434 
1435 	trace_target_sequencer_start(cmd);
1436 
1437 	ret = dev->transport->parse_cdb(cmd);
1438 	if (ret == TCM_UNSUPPORTED_SCSI_OPCODE)
1439 		pr_warn_ratelimited("%s/%s: Unsupported SCSI Opcode 0x%02x, sending CHECK_CONDITION.\n",
1440 				    cmd->se_tfo->fabric_name,
1441 				    cmd->se_sess->se_node_acl->initiatorname,
1442 				    cmd->t_task_cdb[0]);
1443 	if (ret)
1444 		return ret;
1445 
1446 	ret = transport_check_alloc_task_attr(cmd);
1447 	if (ret)
1448 		return ret;
1449 
1450 	cmd->se_cmd_flags |= SCF_SUPPORTED_SAM_OPCODE;
1451 	atomic_long_inc(&cmd->se_lun->lun_stats.cmd_pdus);
1452 	return 0;
1453 }
1454 EXPORT_SYMBOL(target_setup_cmd_from_cdb);
1455 
1456 /*
1457  * Used by fabric module frontends to queue tasks directly.
1458  * May only be used from process context.
1459  */
1460 int transport_handle_cdb_direct(
1461 	struct se_cmd *cmd)
1462 {
1463 	sense_reason_t ret;
1464 
1465 	if (!cmd->se_lun) {
1466 		dump_stack();
1467 		pr_err("cmd->se_lun is NULL\n");
1468 		return -EINVAL;
1469 	}
1470 	if (in_interrupt()) {
1471 		dump_stack();
1472 		pr_err("transport_generic_handle_cdb cannot be called"
1473 				" from interrupt context\n");
1474 		return -EINVAL;
1475 	}
1476 	/*
1477 	 * Set TRANSPORT_NEW_CMD state and CMD_T_ACTIVE to ensure that
1478 	 * outstanding descriptors are handled correctly during shutdown via
1479 	 * transport_wait_for_tasks()
1480 	 *
1481 	 * Also, we don't take cmd->t_state_lock here as we only expect
1482 	 * this to be called for initial descriptor submission.
1483 	 */
1484 	cmd->t_state = TRANSPORT_NEW_CMD;
1485 	cmd->transport_state |= CMD_T_ACTIVE;
1486 
1487 	/*
1488 	 * transport_generic_new_cmd() is already handling QUEUE_FULL,
1489 	 * so follow TRANSPORT_NEW_CMD processing thread context usage
1490 	 * and call transport_generic_request_failure() if necessary..
1491 	 */
1492 	ret = transport_generic_new_cmd(cmd);
1493 	if (ret)
1494 		transport_generic_request_failure(cmd, ret);
1495 	return 0;
1496 }
1497 EXPORT_SYMBOL(transport_handle_cdb_direct);
1498 
1499 sense_reason_t
1500 transport_generic_map_mem_to_cmd(struct se_cmd *cmd, struct scatterlist *sgl,
1501 		u32 sgl_count, struct scatterlist *sgl_bidi, u32 sgl_bidi_count)
1502 {
1503 	if (!sgl || !sgl_count)
1504 		return 0;
1505 
1506 	/*
1507 	 * Reject SCSI data overflow with map_mem_to_cmd() as incoming
1508 	 * scatterlists already have been set to follow what the fabric
1509 	 * passes for the original expected data transfer length.
1510 	 */
1511 	if (cmd->se_cmd_flags & SCF_OVERFLOW_BIT) {
1512 		pr_warn("Rejecting SCSI DATA overflow for fabric using"
1513 			" SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC\n");
1514 		return TCM_INVALID_CDB_FIELD;
1515 	}
1516 
1517 	cmd->t_data_sg = sgl;
1518 	cmd->t_data_nents = sgl_count;
1519 	cmd->t_bidi_data_sg = sgl_bidi;
1520 	cmd->t_bidi_data_nents = sgl_bidi_count;
1521 
1522 	cmd->se_cmd_flags |= SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC;
1523 	return 0;
1524 }
1525 
1526 /**
1527  * target_submit_cmd_map_sgls - lookup unpacked lun and submit uninitialized
1528  * 			 se_cmd + use pre-allocated SGL memory.
1529  *
1530  * @se_cmd: command descriptor to submit
1531  * @se_sess: associated se_sess for endpoint
1532  * @cdb: pointer to SCSI CDB
1533  * @sense: pointer to SCSI sense buffer
1534  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1535  * @data_length: fabric expected data transfer length
1536  * @task_attr: SAM task attribute
1537  * @data_dir: DMA data direction
1538  * @flags: flags for command submission from target_sc_flags_tables
1539  * @sgl: struct scatterlist memory for unidirectional mapping
1540  * @sgl_count: scatterlist count for unidirectional mapping
1541  * @sgl_bidi: struct scatterlist memory for bidirectional READ mapping
1542  * @sgl_bidi_count: scatterlist count for bidirectional READ mapping
1543  * @sgl_prot: struct scatterlist memory protection information
1544  * @sgl_prot_count: scatterlist count for protection information
1545  *
1546  * Task tags are supported if the caller has set @se_cmd->tag.
1547  *
1548  * Returns non zero to signal active I/O shutdown failure.  All other
1549  * setup exceptions will be returned as a SCSI CHECK_CONDITION response,
1550  * but still return zero here.
1551  *
1552  * This may only be called from process context, and also currently
1553  * assumes internal allocation of fabric payload buffer by target-core.
1554  */
1555 int target_submit_cmd_map_sgls(struct se_cmd *se_cmd, struct se_session *se_sess,
1556 		unsigned char *cdb, unsigned char *sense, u64 unpacked_lun,
1557 		u32 data_length, int task_attr, int data_dir, int flags,
1558 		struct scatterlist *sgl, u32 sgl_count,
1559 		struct scatterlist *sgl_bidi, u32 sgl_bidi_count,
1560 		struct scatterlist *sgl_prot, u32 sgl_prot_count)
1561 {
1562 	struct se_portal_group *se_tpg;
1563 	sense_reason_t rc;
1564 	int ret;
1565 
1566 	se_tpg = se_sess->se_tpg;
1567 	BUG_ON(!se_tpg);
1568 	BUG_ON(se_cmd->se_tfo || se_cmd->se_sess);
1569 	BUG_ON(in_interrupt());
1570 	/*
1571 	 * Initialize se_cmd for target operation.  From this point
1572 	 * exceptions are handled by sending exception status via
1573 	 * target_core_fabric_ops->queue_status() callback
1574 	 */
1575 	transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess,
1576 				data_length, data_dir, task_attr, sense);
1577 
1578 	if (flags & TARGET_SCF_USE_CPUID)
1579 		se_cmd->se_cmd_flags |= SCF_USE_CPUID;
1580 	else
1581 		se_cmd->cpuid = WORK_CPU_UNBOUND;
1582 
1583 	if (flags & TARGET_SCF_UNKNOWN_SIZE)
1584 		se_cmd->unknown_data_length = 1;
1585 	/*
1586 	 * Obtain struct se_cmd->cmd_kref reference and add new cmd to
1587 	 * se_sess->sess_cmd_list.  A second kref_get here is necessary
1588 	 * for fabrics using TARGET_SCF_ACK_KREF that expect a second
1589 	 * kref_put() to happen during fabric packet acknowledgement.
1590 	 */
1591 	ret = target_get_sess_cmd(se_cmd, flags & TARGET_SCF_ACK_KREF);
1592 	if (ret)
1593 		return ret;
1594 	/*
1595 	 * Signal bidirectional data payloads to target-core
1596 	 */
1597 	if (flags & TARGET_SCF_BIDI_OP)
1598 		se_cmd->se_cmd_flags |= SCF_BIDI;
1599 	/*
1600 	 * Locate se_lun pointer and attach it to struct se_cmd
1601 	 */
1602 	rc = transport_lookup_cmd_lun(se_cmd, unpacked_lun);
1603 	if (rc) {
1604 		transport_send_check_condition_and_sense(se_cmd, rc, 0);
1605 		target_put_sess_cmd(se_cmd);
1606 		return 0;
1607 	}
1608 
1609 	rc = target_setup_cmd_from_cdb(se_cmd, cdb);
1610 	if (rc != 0) {
1611 		transport_generic_request_failure(se_cmd, rc);
1612 		return 0;
1613 	}
1614 
1615 	/*
1616 	 * Save pointers for SGLs containing protection information,
1617 	 * if present.
1618 	 */
1619 	if (sgl_prot_count) {
1620 		se_cmd->t_prot_sg = sgl_prot;
1621 		se_cmd->t_prot_nents = sgl_prot_count;
1622 		se_cmd->se_cmd_flags |= SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC;
1623 	}
1624 
1625 	/*
1626 	 * When a non zero sgl_count has been passed perform SGL passthrough
1627 	 * mapping for pre-allocated fabric memory instead of having target
1628 	 * core perform an internal SGL allocation..
1629 	 */
1630 	if (sgl_count != 0) {
1631 		BUG_ON(!sgl);
1632 
1633 		/*
1634 		 * A work-around for tcm_loop as some userspace code via
1635 		 * scsi-generic do not memset their associated read buffers,
1636 		 * so go ahead and do that here for type non-data CDBs.  Also
1637 		 * note that this is currently guaranteed to be a single SGL
1638 		 * for this case by target core in target_setup_cmd_from_cdb()
1639 		 * -> transport_generic_cmd_sequencer().
1640 		 */
1641 		if (!(se_cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) &&
1642 		     se_cmd->data_direction == DMA_FROM_DEVICE) {
1643 			unsigned char *buf = NULL;
1644 
1645 			if (sgl)
1646 				buf = kmap(sg_page(sgl)) + sgl->offset;
1647 
1648 			if (buf) {
1649 				memset(buf, 0, sgl->length);
1650 				kunmap(sg_page(sgl));
1651 			}
1652 		}
1653 
1654 		rc = transport_generic_map_mem_to_cmd(se_cmd, sgl, sgl_count,
1655 				sgl_bidi, sgl_bidi_count);
1656 		if (rc != 0) {
1657 			transport_generic_request_failure(se_cmd, rc);
1658 			return 0;
1659 		}
1660 	}
1661 
1662 	/*
1663 	 * Check if we need to delay processing because of ALUA
1664 	 * Active/NonOptimized primary access state..
1665 	 */
1666 	core_alua_check_nonop_delay(se_cmd);
1667 
1668 	transport_handle_cdb_direct(se_cmd);
1669 	return 0;
1670 }
1671 EXPORT_SYMBOL(target_submit_cmd_map_sgls);
1672 
1673 /**
1674  * target_submit_cmd - lookup unpacked lun and submit uninitialized se_cmd
1675  *
1676  * @se_cmd: command descriptor to submit
1677  * @se_sess: associated se_sess for endpoint
1678  * @cdb: pointer to SCSI CDB
1679  * @sense: pointer to SCSI sense buffer
1680  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1681  * @data_length: fabric expected data transfer length
1682  * @task_attr: SAM task attribute
1683  * @data_dir: DMA data direction
1684  * @flags: flags for command submission from target_sc_flags_tables
1685  *
1686  * Task tags are supported if the caller has set @se_cmd->tag.
1687  *
1688  * Returns non zero to signal active I/O shutdown failure.  All other
1689  * setup exceptions will be returned as a SCSI CHECK_CONDITION response,
1690  * but still return zero here.
1691  *
1692  * This may only be called from process context, and also currently
1693  * assumes internal allocation of fabric payload buffer by target-core.
1694  *
1695  * It also assumes interal target core SGL memory allocation.
1696  */
1697 int target_submit_cmd(struct se_cmd *se_cmd, struct se_session *se_sess,
1698 		unsigned char *cdb, unsigned char *sense, u64 unpacked_lun,
1699 		u32 data_length, int task_attr, int data_dir, int flags)
1700 {
1701 	return target_submit_cmd_map_sgls(se_cmd, se_sess, cdb, sense,
1702 			unpacked_lun, data_length, task_attr, data_dir,
1703 			flags, NULL, 0, NULL, 0, NULL, 0);
1704 }
1705 EXPORT_SYMBOL(target_submit_cmd);
1706 
1707 static void target_complete_tmr_failure(struct work_struct *work)
1708 {
1709 	struct se_cmd *se_cmd = container_of(work, struct se_cmd, work);
1710 
1711 	se_cmd->se_tmr_req->response = TMR_LUN_DOES_NOT_EXIST;
1712 	se_cmd->se_tfo->queue_tm_rsp(se_cmd);
1713 
1714 	transport_lun_remove_cmd(se_cmd);
1715 	transport_cmd_check_stop_to_fabric(se_cmd);
1716 }
1717 
1718 static bool target_lookup_lun_from_tag(struct se_session *se_sess, u64 tag,
1719 				       u64 *unpacked_lun)
1720 {
1721 	struct se_cmd *se_cmd;
1722 	unsigned long flags;
1723 	bool ret = false;
1724 
1725 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
1726 	list_for_each_entry(se_cmd, &se_sess->sess_cmd_list, se_cmd_list) {
1727 		if (se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
1728 			continue;
1729 
1730 		if (se_cmd->tag == tag) {
1731 			*unpacked_lun = se_cmd->orig_fe_lun;
1732 			ret = true;
1733 			break;
1734 		}
1735 	}
1736 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
1737 
1738 	return ret;
1739 }
1740 
1741 /**
1742  * target_submit_tmr - lookup unpacked lun and submit uninitialized se_cmd
1743  *                     for TMR CDBs
1744  *
1745  * @se_cmd: command descriptor to submit
1746  * @se_sess: associated se_sess for endpoint
1747  * @sense: pointer to SCSI sense buffer
1748  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1749  * @fabric_tmr_ptr: fabric context for TMR req
1750  * @tm_type: Type of TM request
1751  * @gfp: gfp type for caller
1752  * @tag: referenced task tag for TMR_ABORT_TASK
1753  * @flags: submit cmd flags
1754  *
1755  * Callable from all contexts.
1756  **/
1757 
1758 int target_submit_tmr(struct se_cmd *se_cmd, struct se_session *se_sess,
1759 		unsigned char *sense, u64 unpacked_lun,
1760 		void *fabric_tmr_ptr, unsigned char tm_type,
1761 		gfp_t gfp, u64 tag, int flags)
1762 {
1763 	struct se_portal_group *se_tpg;
1764 	int ret;
1765 
1766 	se_tpg = se_sess->se_tpg;
1767 	BUG_ON(!se_tpg);
1768 
1769 	transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess,
1770 			      0, DMA_NONE, TCM_SIMPLE_TAG, sense);
1771 	/*
1772 	 * FIXME: Currently expect caller to handle se_cmd->se_tmr_req
1773 	 * allocation failure.
1774 	 */
1775 	ret = core_tmr_alloc_req(se_cmd, fabric_tmr_ptr, tm_type, gfp);
1776 	if (ret < 0)
1777 		return -ENOMEM;
1778 
1779 	if (tm_type == TMR_ABORT_TASK)
1780 		se_cmd->se_tmr_req->ref_task_tag = tag;
1781 
1782 	/* See target_submit_cmd for commentary */
1783 	ret = target_get_sess_cmd(se_cmd, flags & TARGET_SCF_ACK_KREF);
1784 	if (ret) {
1785 		core_tmr_release_req(se_cmd->se_tmr_req);
1786 		return ret;
1787 	}
1788 	/*
1789 	 * If this is ABORT_TASK with no explicit fabric provided LUN,
1790 	 * go ahead and search active session tags for a match to figure
1791 	 * out unpacked_lun for the original se_cmd.
1792 	 */
1793 	if (tm_type == TMR_ABORT_TASK && (flags & TARGET_SCF_LOOKUP_LUN_FROM_TAG)) {
1794 		if (!target_lookup_lun_from_tag(se_sess, tag, &unpacked_lun))
1795 			goto failure;
1796 	}
1797 
1798 	ret = transport_lookup_tmr_lun(se_cmd, unpacked_lun);
1799 	if (ret)
1800 		goto failure;
1801 
1802 	transport_generic_handle_tmr(se_cmd);
1803 	return 0;
1804 
1805 	/*
1806 	 * For callback during failure handling, push this work off
1807 	 * to process context with TMR_LUN_DOES_NOT_EXIST status.
1808 	 */
1809 failure:
1810 	INIT_WORK(&se_cmd->work, target_complete_tmr_failure);
1811 	schedule_work(&se_cmd->work);
1812 	return 0;
1813 }
1814 EXPORT_SYMBOL(target_submit_tmr);
1815 
1816 /*
1817  * Handle SAM-esque emulation for generic transport request failures.
1818  */
1819 void transport_generic_request_failure(struct se_cmd *cmd,
1820 		sense_reason_t sense_reason)
1821 {
1822 	int ret = 0, post_ret;
1823 
1824 	pr_debug("-----[ Storage Engine Exception; sense_reason %d\n",
1825 		 sense_reason);
1826 	target_show_cmd("-----[ ", cmd);
1827 
1828 	/*
1829 	 * For SAM Task Attribute emulation for failed struct se_cmd
1830 	 */
1831 	transport_complete_task_attr(cmd);
1832 
1833 	if (cmd->transport_complete_callback)
1834 		cmd->transport_complete_callback(cmd, false, &post_ret);
1835 
1836 	if (cmd->transport_state & CMD_T_ABORTED) {
1837 		INIT_WORK(&cmd->work, target_abort_work);
1838 		queue_work(target_completion_wq, &cmd->work);
1839 		return;
1840 	}
1841 
1842 	switch (sense_reason) {
1843 	case TCM_NON_EXISTENT_LUN:
1844 	case TCM_UNSUPPORTED_SCSI_OPCODE:
1845 	case TCM_INVALID_CDB_FIELD:
1846 	case TCM_INVALID_PARAMETER_LIST:
1847 	case TCM_PARAMETER_LIST_LENGTH_ERROR:
1848 	case TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE:
1849 	case TCM_UNKNOWN_MODE_PAGE:
1850 	case TCM_WRITE_PROTECTED:
1851 	case TCM_ADDRESS_OUT_OF_RANGE:
1852 	case TCM_CHECK_CONDITION_ABORT_CMD:
1853 	case TCM_CHECK_CONDITION_UNIT_ATTENTION:
1854 	case TCM_CHECK_CONDITION_NOT_READY:
1855 	case TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED:
1856 	case TCM_LOGICAL_BLOCK_APP_TAG_CHECK_FAILED:
1857 	case TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED:
1858 	case TCM_COPY_TARGET_DEVICE_NOT_REACHABLE:
1859 	case TCM_TOO_MANY_TARGET_DESCS:
1860 	case TCM_UNSUPPORTED_TARGET_DESC_TYPE_CODE:
1861 	case TCM_TOO_MANY_SEGMENT_DESCS:
1862 	case TCM_UNSUPPORTED_SEGMENT_DESC_TYPE_CODE:
1863 		break;
1864 	case TCM_OUT_OF_RESOURCES:
1865 		cmd->scsi_status = SAM_STAT_TASK_SET_FULL;
1866 		goto queue_status;
1867 	case TCM_LUN_BUSY:
1868 		cmd->scsi_status = SAM_STAT_BUSY;
1869 		goto queue_status;
1870 	case TCM_RESERVATION_CONFLICT:
1871 		/*
1872 		 * No SENSE Data payload for this case, set SCSI Status
1873 		 * and queue the response to $FABRIC_MOD.
1874 		 *
1875 		 * Uses linux/include/scsi/scsi.h SAM status codes defs
1876 		 */
1877 		cmd->scsi_status = SAM_STAT_RESERVATION_CONFLICT;
1878 		/*
1879 		 * For UA Interlock Code 11b, a RESERVATION CONFLICT will
1880 		 * establish a UNIT ATTENTION with PREVIOUS RESERVATION
1881 		 * CONFLICT STATUS.
1882 		 *
1883 		 * See spc4r17, section 7.4.6 Control Mode Page, Table 349
1884 		 */
1885 		if (cmd->se_sess &&
1886 		    cmd->se_dev->dev_attrib.emulate_ua_intlck_ctrl == 2) {
1887 			target_ua_allocate_lun(cmd->se_sess->se_node_acl,
1888 					       cmd->orig_fe_lun, 0x2C,
1889 					ASCQ_2CH_PREVIOUS_RESERVATION_CONFLICT_STATUS);
1890 		}
1891 
1892 		goto queue_status;
1893 	default:
1894 		pr_err("Unknown transport error for CDB 0x%02x: %d\n",
1895 			cmd->t_task_cdb[0], sense_reason);
1896 		sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
1897 		break;
1898 	}
1899 
1900 	ret = transport_send_check_condition_and_sense(cmd, sense_reason, 0);
1901 	if (ret)
1902 		goto queue_full;
1903 
1904 check_stop:
1905 	transport_lun_remove_cmd(cmd);
1906 	transport_cmd_check_stop_to_fabric(cmd);
1907 	return;
1908 
1909 queue_status:
1910 	trace_target_cmd_complete(cmd);
1911 	ret = cmd->se_tfo->queue_status(cmd);
1912 	if (!ret)
1913 		goto check_stop;
1914 queue_full:
1915 	transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
1916 }
1917 EXPORT_SYMBOL(transport_generic_request_failure);
1918 
1919 void __target_execute_cmd(struct se_cmd *cmd, bool do_checks)
1920 {
1921 	sense_reason_t ret;
1922 
1923 	if (!cmd->execute_cmd) {
1924 		ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
1925 		goto err;
1926 	}
1927 	if (do_checks) {
1928 		/*
1929 		 * Check for an existing UNIT ATTENTION condition after
1930 		 * target_handle_task_attr() has done SAM task attr
1931 		 * checking, and possibly have already defered execution
1932 		 * out to target_restart_delayed_cmds() context.
1933 		 */
1934 		ret = target_scsi3_ua_check(cmd);
1935 		if (ret)
1936 			goto err;
1937 
1938 		ret = target_alua_state_check(cmd);
1939 		if (ret)
1940 			goto err;
1941 
1942 		ret = target_check_reservation(cmd);
1943 		if (ret) {
1944 			cmd->scsi_status = SAM_STAT_RESERVATION_CONFLICT;
1945 			goto err;
1946 		}
1947 	}
1948 
1949 	ret = cmd->execute_cmd(cmd);
1950 	if (!ret)
1951 		return;
1952 err:
1953 	spin_lock_irq(&cmd->t_state_lock);
1954 	cmd->transport_state &= ~CMD_T_SENT;
1955 	spin_unlock_irq(&cmd->t_state_lock);
1956 
1957 	transport_generic_request_failure(cmd, ret);
1958 }
1959 
1960 static int target_write_prot_action(struct se_cmd *cmd)
1961 {
1962 	u32 sectors;
1963 	/*
1964 	 * Perform WRITE_INSERT of PI using software emulation when backend
1965 	 * device has PI enabled, if the transport has not already generated
1966 	 * PI using hardware WRITE_INSERT offload.
1967 	 */
1968 	switch (cmd->prot_op) {
1969 	case TARGET_PROT_DOUT_INSERT:
1970 		if (!(cmd->se_sess->sup_prot_ops & TARGET_PROT_DOUT_INSERT))
1971 			sbc_dif_generate(cmd);
1972 		break;
1973 	case TARGET_PROT_DOUT_STRIP:
1974 		if (cmd->se_sess->sup_prot_ops & TARGET_PROT_DOUT_STRIP)
1975 			break;
1976 
1977 		sectors = cmd->data_length >> ilog2(cmd->se_dev->dev_attrib.block_size);
1978 		cmd->pi_err = sbc_dif_verify(cmd, cmd->t_task_lba,
1979 					     sectors, 0, cmd->t_prot_sg, 0);
1980 		if (unlikely(cmd->pi_err)) {
1981 			spin_lock_irq(&cmd->t_state_lock);
1982 			cmd->transport_state &= ~CMD_T_SENT;
1983 			spin_unlock_irq(&cmd->t_state_lock);
1984 			transport_generic_request_failure(cmd, cmd->pi_err);
1985 			return -1;
1986 		}
1987 		break;
1988 	default:
1989 		break;
1990 	}
1991 
1992 	return 0;
1993 }
1994 
1995 static bool target_handle_task_attr(struct se_cmd *cmd)
1996 {
1997 	struct se_device *dev = cmd->se_dev;
1998 
1999 	if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
2000 		return false;
2001 
2002 	cmd->se_cmd_flags |= SCF_TASK_ATTR_SET;
2003 
2004 	/*
2005 	 * Check for the existence of HEAD_OF_QUEUE, and if true return 1
2006 	 * to allow the passed struct se_cmd list of tasks to the front of the list.
2007 	 */
2008 	switch (cmd->sam_task_attr) {
2009 	case TCM_HEAD_TAG:
2010 		pr_debug("Added HEAD_OF_QUEUE for CDB: 0x%02x\n",
2011 			 cmd->t_task_cdb[0]);
2012 		return false;
2013 	case TCM_ORDERED_TAG:
2014 		atomic_inc_mb(&dev->dev_ordered_sync);
2015 
2016 		pr_debug("Added ORDERED for CDB: 0x%02x to ordered list\n",
2017 			 cmd->t_task_cdb[0]);
2018 
2019 		/*
2020 		 * Execute an ORDERED command if no other older commands
2021 		 * exist that need to be completed first.
2022 		 */
2023 		if (!atomic_read(&dev->simple_cmds))
2024 			return false;
2025 		break;
2026 	default:
2027 		/*
2028 		 * For SIMPLE and UNTAGGED Task Attribute commands
2029 		 */
2030 		atomic_inc_mb(&dev->simple_cmds);
2031 		break;
2032 	}
2033 
2034 	if (atomic_read(&dev->dev_ordered_sync) == 0)
2035 		return false;
2036 
2037 	spin_lock(&dev->delayed_cmd_lock);
2038 	list_add_tail(&cmd->se_delayed_node, &dev->delayed_cmd_list);
2039 	spin_unlock(&dev->delayed_cmd_lock);
2040 
2041 	pr_debug("Added CDB: 0x%02x Task Attr: 0x%02x to delayed CMD listn",
2042 		cmd->t_task_cdb[0], cmd->sam_task_attr);
2043 	return true;
2044 }
2045 
2046 void target_execute_cmd(struct se_cmd *cmd)
2047 {
2048 	/*
2049 	 * Determine if frontend context caller is requesting the stopping of
2050 	 * this command for frontend exceptions.
2051 	 *
2052 	 * If the received CDB has already been aborted stop processing it here.
2053 	 */
2054 	if (target_cmd_interrupted(cmd))
2055 		return;
2056 
2057 	spin_lock_irq(&cmd->t_state_lock);
2058 	cmd->t_state = TRANSPORT_PROCESSING;
2059 	cmd->transport_state &= ~CMD_T_PRE_EXECUTE;
2060 	cmd->transport_state |= CMD_T_ACTIVE | CMD_T_SENT;
2061 	spin_unlock_irq(&cmd->t_state_lock);
2062 
2063 	if (target_write_prot_action(cmd))
2064 		return;
2065 
2066 	if (target_handle_task_attr(cmd)) {
2067 		spin_lock_irq(&cmd->t_state_lock);
2068 		cmd->transport_state &= ~CMD_T_SENT;
2069 		spin_unlock_irq(&cmd->t_state_lock);
2070 		return;
2071 	}
2072 
2073 	__target_execute_cmd(cmd, true);
2074 }
2075 EXPORT_SYMBOL(target_execute_cmd);
2076 
2077 /*
2078  * Process all commands up to the last received ORDERED task attribute which
2079  * requires another blocking boundary
2080  */
2081 static void target_restart_delayed_cmds(struct se_device *dev)
2082 {
2083 	for (;;) {
2084 		struct se_cmd *cmd;
2085 
2086 		spin_lock(&dev->delayed_cmd_lock);
2087 		if (list_empty(&dev->delayed_cmd_list)) {
2088 			spin_unlock(&dev->delayed_cmd_lock);
2089 			break;
2090 		}
2091 
2092 		cmd = list_entry(dev->delayed_cmd_list.next,
2093 				 struct se_cmd, se_delayed_node);
2094 		list_del(&cmd->se_delayed_node);
2095 		spin_unlock(&dev->delayed_cmd_lock);
2096 
2097 		cmd->transport_state |= CMD_T_SENT;
2098 
2099 		__target_execute_cmd(cmd, true);
2100 
2101 		if (cmd->sam_task_attr == TCM_ORDERED_TAG)
2102 			break;
2103 	}
2104 }
2105 
2106 /*
2107  * Called from I/O completion to determine which dormant/delayed
2108  * and ordered cmds need to have their tasks added to the execution queue.
2109  */
2110 static void transport_complete_task_attr(struct se_cmd *cmd)
2111 {
2112 	struct se_device *dev = cmd->se_dev;
2113 
2114 	if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
2115 		return;
2116 
2117 	if (!(cmd->se_cmd_flags & SCF_TASK_ATTR_SET))
2118 		goto restart;
2119 
2120 	if (cmd->sam_task_attr == TCM_SIMPLE_TAG) {
2121 		atomic_dec_mb(&dev->simple_cmds);
2122 		dev->dev_cur_ordered_id++;
2123 	} else if (cmd->sam_task_attr == TCM_HEAD_TAG) {
2124 		dev->dev_cur_ordered_id++;
2125 		pr_debug("Incremented dev_cur_ordered_id: %u for HEAD_OF_QUEUE\n",
2126 			 dev->dev_cur_ordered_id);
2127 	} else if (cmd->sam_task_attr == TCM_ORDERED_TAG) {
2128 		atomic_dec_mb(&dev->dev_ordered_sync);
2129 
2130 		dev->dev_cur_ordered_id++;
2131 		pr_debug("Incremented dev_cur_ordered_id: %u for ORDERED\n",
2132 			 dev->dev_cur_ordered_id);
2133 	}
2134 	cmd->se_cmd_flags &= ~SCF_TASK_ATTR_SET;
2135 
2136 restart:
2137 	target_restart_delayed_cmds(dev);
2138 }
2139 
2140 static void transport_complete_qf(struct se_cmd *cmd)
2141 {
2142 	int ret = 0;
2143 
2144 	transport_complete_task_attr(cmd);
2145 	/*
2146 	 * If a fabric driver ->write_pending() or ->queue_data_in() callback
2147 	 * has returned neither -ENOMEM or -EAGAIN, assume it's fatal and
2148 	 * the same callbacks should not be retried.  Return CHECK_CONDITION
2149 	 * if a scsi_status is not already set.
2150 	 *
2151 	 * If a fabric driver ->queue_status() has returned non zero, always
2152 	 * keep retrying no matter what..
2153 	 */
2154 	if (cmd->t_state == TRANSPORT_COMPLETE_QF_ERR) {
2155 		if (cmd->scsi_status)
2156 			goto queue_status;
2157 
2158 		translate_sense_reason(cmd, TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE);
2159 		goto queue_status;
2160 	}
2161 
2162 	/*
2163 	 * Check if we need to send a sense buffer from
2164 	 * the struct se_cmd in question. We do NOT want
2165 	 * to take this path of the IO has been marked as
2166 	 * needing to be treated like a "normal read". This
2167 	 * is the case if it's a tape read, and either the
2168 	 * FM, EOM, or ILI bits are set, but there is no
2169 	 * sense data.
2170 	 */
2171 	if (!(cmd->se_cmd_flags & SCF_TREAT_READ_AS_NORMAL) &&
2172 	    cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE)
2173 		goto queue_status;
2174 
2175 	switch (cmd->data_direction) {
2176 	case DMA_FROM_DEVICE:
2177 		/* queue status if not treating this as a normal read */
2178 		if (cmd->scsi_status &&
2179 		    !(cmd->se_cmd_flags & SCF_TREAT_READ_AS_NORMAL))
2180 			goto queue_status;
2181 
2182 		trace_target_cmd_complete(cmd);
2183 		ret = cmd->se_tfo->queue_data_in(cmd);
2184 		break;
2185 	case DMA_TO_DEVICE:
2186 		if (cmd->se_cmd_flags & SCF_BIDI) {
2187 			ret = cmd->se_tfo->queue_data_in(cmd);
2188 			break;
2189 		}
2190 		/* fall through */
2191 	case DMA_NONE:
2192 queue_status:
2193 		trace_target_cmd_complete(cmd);
2194 		ret = cmd->se_tfo->queue_status(cmd);
2195 		break;
2196 	default:
2197 		break;
2198 	}
2199 
2200 	if (ret < 0) {
2201 		transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
2202 		return;
2203 	}
2204 	transport_lun_remove_cmd(cmd);
2205 	transport_cmd_check_stop_to_fabric(cmd);
2206 }
2207 
2208 static void transport_handle_queue_full(struct se_cmd *cmd, struct se_device *dev,
2209 					int err, bool write_pending)
2210 {
2211 	/*
2212 	 * -EAGAIN or -ENOMEM signals retry of ->write_pending() and/or
2213 	 * ->queue_data_in() callbacks from new process context.
2214 	 *
2215 	 * Otherwise for other errors, transport_complete_qf() will send
2216 	 * CHECK_CONDITION via ->queue_status() instead of attempting to
2217 	 * retry associated fabric driver data-transfer callbacks.
2218 	 */
2219 	if (err == -EAGAIN || err == -ENOMEM) {
2220 		cmd->t_state = (write_pending) ? TRANSPORT_COMPLETE_QF_WP :
2221 						 TRANSPORT_COMPLETE_QF_OK;
2222 	} else {
2223 		pr_warn_ratelimited("Got unknown fabric queue status: %d\n", err);
2224 		cmd->t_state = TRANSPORT_COMPLETE_QF_ERR;
2225 	}
2226 
2227 	spin_lock_irq(&dev->qf_cmd_lock);
2228 	list_add_tail(&cmd->se_qf_node, &cmd->se_dev->qf_cmd_list);
2229 	atomic_inc_mb(&dev->dev_qf_count);
2230 	spin_unlock_irq(&cmd->se_dev->qf_cmd_lock);
2231 
2232 	schedule_work(&cmd->se_dev->qf_work_queue);
2233 }
2234 
2235 static bool target_read_prot_action(struct se_cmd *cmd)
2236 {
2237 	switch (cmd->prot_op) {
2238 	case TARGET_PROT_DIN_STRIP:
2239 		if (!(cmd->se_sess->sup_prot_ops & TARGET_PROT_DIN_STRIP)) {
2240 			u32 sectors = cmd->data_length >>
2241 				  ilog2(cmd->se_dev->dev_attrib.block_size);
2242 
2243 			cmd->pi_err = sbc_dif_verify(cmd, cmd->t_task_lba,
2244 						     sectors, 0, cmd->t_prot_sg,
2245 						     0);
2246 			if (cmd->pi_err)
2247 				return true;
2248 		}
2249 		break;
2250 	case TARGET_PROT_DIN_INSERT:
2251 		if (cmd->se_sess->sup_prot_ops & TARGET_PROT_DIN_INSERT)
2252 			break;
2253 
2254 		sbc_dif_generate(cmd);
2255 		break;
2256 	default:
2257 		break;
2258 	}
2259 
2260 	return false;
2261 }
2262 
2263 static void target_complete_ok_work(struct work_struct *work)
2264 {
2265 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
2266 	int ret;
2267 
2268 	/*
2269 	 * Check if we need to move delayed/dormant tasks from cmds on the
2270 	 * delayed execution list after a HEAD_OF_QUEUE or ORDERED Task
2271 	 * Attribute.
2272 	 */
2273 	transport_complete_task_attr(cmd);
2274 
2275 	/*
2276 	 * Check to schedule QUEUE_FULL work, or execute an existing
2277 	 * cmd->transport_qf_callback()
2278 	 */
2279 	if (atomic_read(&cmd->se_dev->dev_qf_count) != 0)
2280 		schedule_work(&cmd->se_dev->qf_work_queue);
2281 
2282 	/*
2283 	 * Check if we need to send a sense buffer from
2284 	 * the struct se_cmd in question. We do NOT want
2285 	 * to take this path of the IO has been marked as
2286 	 * needing to be treated like a "normal read". This
2287 	 * is the case if it's a tape read, and either the
2288 	 * FM, EOM, or ILI bits are set, but there is no
2289 	 * sense data.
2290 	 */
2291 	if (!(cmd->se_cmd_flags & SCF_TREAT_READ_AS_NORMAL) &&
2292 	    cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) {
2293 		WARN_ON(!cmd->scsi_status);
2294 		ret = transport_send_check_condition_and_sense(
2295 					cmd, 0, 1);
2296 		if (ret)
2297 			goto queue_full;
2298 
2299 		transport_lun_remove_cmd(cmd);
2300 		transport_cmd_check_stop_to_fabric(cmd);
2301 		return;
2302 	}
2303 	/*
2304 	 * Check for a callback, used by amongst other things
2305 	 * XDWRITE_READ_10 and COMPARE_AND_WRITE emulation.
2306 	 */
2307 	if (cmd->transport_complete_callback) {
2308 		sense_reason_t rc;
2309 		bool caw = (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE);
2310 		bool zero_dl = !(cmd->data_length);
2311 		int post_ret = 0;
2312 
2313 		rc = cmd->transport_complete_callback(cmd, true, &post_ret);
2314 		if (!rc && !post_ret) {
2315 			if (caw && zero_dl)
2316 				goto queue_rsp;
2317 
2318 			return;
2319 		} else if (rc) {
2320 			ret = transport_send_check_condition_and_sense(cmd,
2321 						rc, 0);
2322 			if (ret)
2323 				goto queue_full;
2324 
2325 			transport_lun_remove_cmd(cmd);
2326 			transport_cmd_check_stop_to_fabric(cmd);
2327 			return;
2328 		}
2329 	}
2330 
2331 queue_rsp:
2332 	switch (cmd->data_direction) {
2333 	case DMA_FROM_DEVICE:
2334 		/*
2335 		 * if this is a READ-type IO, but SCSI status
2336 		 * is set, then skip returning data and just
2337 		 * return the status -- unless this IO is marked
2338 		 * as needing to be treated as a normal read,
2339 		 * in which case we want to go ahead and return
2340 		 * the data. This happens, for example, for tape
2341 		 * reads with the FM, EOM, or ILI bits set, with
2342 		 * no sense data.
2343 		 */
2344 		if (cmd->scsi_status &&
2345 		    !(cmd->se_cmd_flags & SCF_TREAT_READ_AS_NORMAL))
2346 			goto queue_status;
2347 
2348 		atomic_long_add(cmd->data_length,
2349 				&cmd->se_lun->lun_stats.tx_data_octets);
2350 		/*
2351 		 * Perform READ_STRIP of PI using software emulation when
2352 		 * backend had PI enabled, if the transport will not be
2353 		 * performing hardware READ_STRIP offload.
2354 		 */
2355 		if (target_read_prot_action(cmd)) {
2356 			ret = transport_send_check_condition_and_sense(cmd,
2357 						cmd->pi_err, 0);
2358 			if (ret)
2359 				goto queue_full;
2360 
2361 			transport_lun_remove_cmd(cmd);
2362 			transport_cmd_check_stop_to_fabric(cmd);
2363 			return;
2364 		}
2365 
2366 		trace_target_cmd_complete(cmd);
2367 		ret = cmd->se_tfo->queue_data_in(cmd);
2368 		if (ret)
2369 			goto queue_full;
2370 		break;
2371 	case DMA_TO_DEVICE:
2372 		atomic_long_add(cmd->data_length,
2373 				&cmd->se_lun->lun_stats.rx_data_octets);
2374 		/*
2375 		 * Check if we need to send READ payload for BIDI-COMMAND
2376 		 */
2377 		if (cmd->se_cmd_flags & SCF_BIDI) {
2378 			atomic_long_add(cmd->data_length,
2379 					&cmd->se_lun->lun_stats.tx_data_octets);
2380 			ret = cmd->se_tfo->queue_data_in(cmd);
2381 			if (ret)
2382 				goto queue_full;
2383 			break;
2384 		}
2385 		/* fall through */
2386 	case DMA_NONE:
2387 queue_status:
2388 		trace_target_cmd_complete(cmd);
2389 		ret = cmd->se_tfo->queue_status(cmd);
2390 		if (ret)
2391 			goto queue_full;
2392 		break;
2393 	default:
2394 		break;
2395 	}
2396 
2397 	transport_lun_remove_cmd(cmd);
2398 	transport_cmd_check_stop_to_fabric(cmd);
2399 	return;
2400 
2401 queue_full:
2402 	pr_debug("Handling complete_ok QUEUE_FULL: se_cmd: %p,"
2403 		" data_direction: %d\n", cmd, cmd->data_direction);
2404 
2405 	transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
2406 }
2407 
2408 void target_free_sgl(struct scatterlist *sgl, int nents)
2409 {
2410 	sgl_free_n_order(sgl, nents, 0);
2411 }
2412 EXPORT_SYMBOL(target_free_sgl);
2413 
2414 static inline void transport_reset_sgl_orig(struct se_cmd *cmd)
2415 {
2416 	/*
2417 	 * Check for saved t_data_sg that may be used for COMPARE_AND_WRITE
2418 	 * emulation, and free + reset pointers if necessary..
2419 	 */
2420 	if (!cmd->t_data_sg_orig)
2421 		return;
2422 
2423 	kfree(cmd->t_data_sg);
2424 	cmd->t_data_sg = cmd->t_data_sg_orig;
2425 	cmd->t_data_sg_orig = NULL;
2426 	cmd->t_data_nents = cmd->t_data_nents_orig;
2427 	cmd->t_data_nents_orig = 0;
2428 }
2429 
2430 static inline void transport_free_pages(struct se_cmd *cmd)
2431 {
2432 	if (!(cmd->se_cmd_flags & SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC)) {
2433 		target_free_sgl(cmd->t_prot_sg, cmd->t_prot_nents);
2434 		cmd->t_prot_sg = NULL;
2435 		cmd->t_prot_nents = 0;
2436 	}
2437 
2438 	if (cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) {
2439 		/*
2440 		 * Release special case READ buffer payload required for
2441 		 * SG_TO_MEM_NOALLOC to function with COMPARE_AND_WRITE
2442 		 */
2443 		if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) {
2444 			target_free_sgl(cmd->t_bidi_data_sg,
2445 					   cmd->t_bidi_data_nents);
2446 			cmd->t_bidi_data_sg = NULL;
2447 			cmd->t_bidi_data_nents = 0;
2448 		}
2449 		transport_reset_sgl_orig(cmd);
2450 		return;
2451 	}
2452 	transport_reset_sgl_orig(cmd);
2453 
2454 	target_free_sgl(cmd->t_data_sg, cmd->t_data_nents);
2455 	cmd->t_data_sg = NULL;
2456 	cmd->t_data_nents = 0;
2457 
2458 	target_free_sgl(cmd->t_bidi_data_sg, cmd->t_bidi_data_nents);
2459 	cmd->t_bidi_data_sg = NULL;
2460 	cmd->t_bidi_data_nents = 0;
2461 }
2462 
2463 void *transport_kmap_data_sg(struct se_cmd *cmd)
2464 {
2465 	struct scatterlist *sg = cmd->t_data_sg;
2466 	struct page **pages;
2467 	int i;
2468 
2469 	/*
2470 	 * We need to take into account a possible offset here for fabrics like
2471 	 * tcm_loop who may be using a contig buffer from the SCSI midlayer for
2472 	 * control CDBs passed as SGLs via transport_generic_map_mem_to_cmd()
2473 	 */
2474 	if (!cmd->t_data_nents)
2475 		return NULL;
2476 
2477 	BUG_ON(!sg);
2478 	if (cmd->t_data_nents == 1)
2479 		return kmap(sg_page(sg)) + sg->offset;
2480 
2481 	/* >1 page. use vmap */
2482 	pages = kmalloc_array(cmd->t_data_nents, sizeof(*pages), GFP_KERNEL);
2483 	if (!pages)
2484 		return NULL;
2485 
2486 	/* convert sg[] to pages[] */
2487 	for_each_sg(cmd->t_data_sg, sg, cmd->t_data_nents, i) {
2488 		pages[i] = sg_page(sg);
2489 	}
2490 
2491 	cmd->t_data_vmap = vmap(pages, cmd->t_data_nents,  VM_MAP, PAGE_KERNEL);
2492 	kfree(pages);
2493 	if (!cmd->t_data_vmap)
2494 		return NULL;
2495 
2496 	return cmd->t_data_vmap + cmd->t_data_sg[0].offset;
2497 }
2498 EXPORT_SYMBOL(transport_kmap_data_sg);
2499 
2500 void transport_kunmap_data_sg(struct se_cmd *cmd)
2501 {
2502 	if (!cmd->t_data_nents) {
2503 		return;
2504 	} else if (cmd->t_data_nents == 1) {
2505 		kunmap(sg_page(cmd->t_data_sg));
2506 		return;
2507 	}
2508 
2509 	vunmap(cmd->t_data_vmap);
2510 	cmd->t_data_vmap = NULL;
2511 }
2512 EXPORT_SYMBOL(transport_kunmap_data_sg);
2513 
2514 int
2515 target_alloc_sgl(struct scatterlist **sgl, unsigned int *nents, u32 length,
2516 		 bool zero_page, bool chainable)
2517 {
2518 	gfp_t gfp = GFP_KERNEL | (zero_page ? __GFP_ZERO : 0);
2519 
2520 	*sgl = sgl_alloc_order(length, 0, chainable, gfp, nents);
2521 	return *sgl ? 0 : -ENOMEM;
2522 }
2523 EXPORT_SYMBOL(target_alloc_sgl);
2524 
2525 /*
2526  * Allocate any required resources to execute the command.  For writes we
2527  * might not have the payload yet, so notify the fabric via a call to
2528  * ->write_pending instead. Otherwise place it on the execution queue.
2529  */
2530 sense_reason_t
2531 transport_generic_new_cmd(struct se_cmd *cmd)
2532 {
2533 	unsigned long flags;
2534 	int ret = 0;
2535 	bool zero_flag = !(cmd->se_cmd_flags & SCF_SCSI_DATA_CDB);
2536 
2537 	if (cmd->prot_op != TARGET_PROT_NORMAL &&
2538 	    !(cmd->se_cmd_flags & SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC)) {
2539 		ret = target_alloc_sgl(&cmd->t_prot_sg, &cmd->t_prot_nents,
2540 				       cmd->prot_length, true, false);
2541 		if (ret < 0)
2542 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2543 	}
2544 
2545 	/*
2546 	 * Determine if the TCM fabric module has already allocated physical
2547 	 * memory, and is directly calling transport_generic_map_mem_to_cmd()
2548 	 * beforehand.
2549 	 */
2550 	if (!(cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) &&
2551 	    cmd->data_length) {
2552 
2553 		if ((cmd->se_cmd_flags & SCF_BIDI) ||
2554 		    (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE)) {
2555 			u32 bidi_length;
2556 
2557 			if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE)
2558 				bidi_length = cmd->t_task_nolb *
2559 					      cmd->se_dev->dev_attrib.block_size;
2560 			else
2561 				bidi_length = cmd->data_length;
2562 
2563 			ret = target_alloc_sgl(&cmd->t_bidi_data_sg,
2564 					       &cmd->t_bidi_data_nents,
2565 					       bidi_length, zero_flag, false);
2566 			if (ret < 0)
2567 				return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2568 		}
2569 
2570 		ret = target_alloc_sgl(&cmd->t_data_sg, &cmd->t_data_nents,
2571 				       cmd->data_length, zero_flag, false);
2572 		if (ret < 0)
2573 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2574 	} else if ((cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) &&
2575 		    cmd->data_length) {
2576 		/*
2577 		 * Special case for COMPARE_AND_WRITE with fabrics
2578 		 * using SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC.
2579 		 */
2580 		u32 caw_length = cmd->t_task_nolb *
2581 				 cmd->se_dev->dev_attrib.block_size;
2582 
2583 		ret = target_alloc_sgl(&cmd->t_bidi_data_sg,
2584 				       &cmd->t_bidi_data_nents,
2585 				       caw_length, zero_flag, false);
2586 		if (ret < 0)
2587 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2588 	}
2589 	/*
2590 	 * If this command is not a write we can execute it right here,
2591 	 * for write buffers we need to notify the fabric driver first
2592 	 * and let it call back once the write buffers are ready.
2593 	 */
2594 	target_add_to_state_list(cmd);
2595 	if (cmd->data_direction != DMA_TO_DEVICE || cmd->data_length == 0) {
2596 		target_execute_cmd(cmd);
2597 		return 0;
2598 	}
2599 
2600 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2601 	cmd->t_state = TRANSPORT_WRITE_PENDING;
2602 	/*
2603 	 * Determine if frontend context caller is requesting the stopping of
2604 	 * this command for frontend exceptions.
2605 	 */
2606 	if (cmd->transport_state & CMD_T_STOP &&
2607 	    !cmd->se_tfo->write_pending_must_be_called) {
2608 		pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08llx\n",
2609 			 __func__, __LINE__, cmd->tag);
2610 
2611 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2612 
2613 		complete_all(&cmd->t_transport_stop_comp);
2614 		return 0;
2615 	}
2616 	cmd->transport_state &= ~CMD_T_ACTIVE;
2617 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2618 
2619 	ret = cmd->se_tfo->write_pending(cmd);
2620 	if (ret)
2621 		goto queue_full;
2622 
2623 	return 0;
2624 
2625 queue_full:
2626 	pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n", cmd);
2627 	transport_handle_queue_full(cmd, cmd->se_dev, ret, true);
2628 	return 0;
2629 }
2630 EXPORT_SYMBOL(transport_generic_new_cmd);
2631 
2632 static void transport_write_pending_qf(struct se_cmd *cmd)
2633 {
2634 	unsigned long flags;
2635 	int ret;
2636 	bool stop;
2637 
2638 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2639 	stop = (cmd->transport_state & (CMD_T_STOP | CMD_T_ABORTED));
2640 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2641 
2642 	if (stop) {
2643 		pr_debug("%s:%d CMD_T_STOP|CMD_T_ABORTED for ITT: 0x%08llx\n",
2644 			__func__, __LINE__, cmd->tag);
2645 		complete_all(&cmd->t_transport_stop_comp);
2646 		return;
2647 	}
2648 
2649 	ret = cmd->se_tfo->write_pending(cmd);
2650 	if (ret) {
2651 		pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n",
2652 			 cmd);
2653 		transport_handle_queue_full(cmd, cmd->se_dev, ret, true);
2654 	}
2655 }
2656 
2657 static bool
2658 __transport_wait_for_tasks(struct se_cmd *, bool, bool *, bool *,
2659 			   unsigned long *flags);
2660 
2661 static void target_wait_free_cmd(struct se_cmd *cmd, bool *aborted, bool *tas)
2662 {
2663 	unsigned long flags;
2664 
2665 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2666 	__transport_wait_for_tasks(cmd, true, aborted, tas, &flags);
2667 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2668 }
2669 
2670 /*
2671  * Call target_put_sess_cmd() and wait until target_release_cmd_kref(@cmd) has
2672  * finished.
2673  */
2674 void target_put_cmd_and_wait(struct se_cmd *cmd)
2675 {
2676 	DECLARE_COMPLETION_ONSTACK(compl);
2677 
2678 	WARN_ON_ONCE(cmd->abrt_compl);
2679 	cmd->abrt_compl = &compl;
2680 	target_put_sess_cmd(cmd);
2681 	wait_for_completion(&compl);
2682 }
2683 
2684 /*
2685  * This function is called by frontend drivers after processing of a command
2686  * has finished.
2687  *
2688  * The protocol for ensuring that either the regular frontend command
2689  * processing flow or target_handle_abort() code drops one reference is as
2690  * follows:
2691  * - Calling .queue_data_in(), .queue_status() or queue_tm_rsp() will cause
2692  *   the frontend driver to call this function synchronously or asynchronously.
2693  *   That will cause one reference to be dropped.
2694  * - During regular command processing the target core sets CMD_T_COMPLETE
2695  *   before invoking one of the .queue_*() functions.
2696  * - The code that aborts commands skips commands and TMFs for which
2697  *   CMD_T_COMPLETE has been set.
2698  * - CMD_T_ABORTED is set atomically after the CMD_T_COMPLETE check for
2699  *   commands that will be aborted.
2700  * - If the CMD_T_ABORTED flag is set but CMD_T_TAS has not been set
2701  *   transport_generic_free_cmd() skips its call to target_put_sess_cmd().
2702  * - For aborted commands for which CMD_T_TAS has been set .queue_status() will
2703  *   be called and will drop a reference.
2704  * - For aborted commands for which CMD_T_TAS has not been set .aborted_task()
2705  *   will be called. target_handle_abort() will drop the final reference.
2706  */
2707 int transport_generic_free_cmd(struct se_cmd *cmd, int wait_for_tasks)
2708 {
2709 	DECLARE_COMPLETION_ONSTACK(compl);
2710 	int ret = 0;
2711 	bool aborted = false, tas = false;
2712 
2713 	if (wait_for_tasks)
2714 		target_wait_free_cmd(cmd, &aborted, &tas);
2715 
2716 	if (cmd->se_cmd_flags & SCF_SE_LUN_CMD) {
2717 		/*
2718 		 * Handle WRITE failure case where transport_generic_new_cmd()
2719 		 * has already added se_cmd to state_list, but fabric has
2720 		 * failed command before I/O submission.
2721 		 */
2722 		if (cmd->state_active)
2723 			target_remove_from_state_list(cmd);
2724 
2725 		if (cmd->se_lun)
2726 			transport_lun_remove_cmd(cmd);
2727 	}
2728 	if (aborted)
2729 		cmd->free_compl = &compl;
2730 	ret = target_put_sess_cmd(cmd);
2731 	if (aborted) {
2732 		pr_debug("Detected CMD_T_ABORTED for ITT: %llu\n", cmd->tag);
2733 		wait_for_completion(&compl);
2734 		ret = 1;
2735 	}
2736 	return ret;
2737 }
2738 EXPORT_SYMBOL(transport_generic_free_cmd);
2739 
2740 /**
2741  * target_get_sess_cmd - Add command to active ->sess_cmd_list
2742  * @se_cmd:	command descriptor to add
2743  * @ack_kref:	Signal that fabric will perform an ack target_put_sess_cmd()
2744  */
2745 int target_get_sess_cmd(struct se_cmd *se_cmd, bool ack_kref)
2746 {
2747 	struct se_session *se_sess = se_cmd->se_sess;
2748 	unsigned long flags;
2749 	int ret = 0;
2750 
2751 	/*
2752 	 * Add a second kref if the fabric caller is expecting to handle
2753 	 * fabric acknowledgement that requires two target_put_sess_cmd()
2754 	 * invocations before se_cmd descriptor release.
2755 	 */
2756 	if (ack_kref) {
2757 		if (!kref_get_unless_zero(&se_cmd->cmd_kref))
2758 			return -EINVAL;
2759 
2760 		se_cmd->se_cmd_flags |= SCF_ACK_KREF;
2761 	}
2762 
2763 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2764 	if (se_sess->sess_tearing_down) {
2765 		ret = -ESHUTDOWN;
2766 		goto out;
2767 	}
2768 	se_cmd->transport_state |= CMD_T_PRE_EXECUTE;
2769 	list_add_tail(&se_cmd->se_cmd_list, &se_sess->sess_cmd_list);
2770 	percpu_ref_get(&se_sess->cmd_count);
2771 out:
2772 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2773 
2774 	if (ret && ack_kref)
2775 		target_put_sess_cmd(se_cmd);
2776 
2777 	return ret;
2778 }
2779 EXPORT_SYMBOL(target_get_sess_cmd);
2780 
2781 static void target_free_cmd_mem(struct se_cmd *cmd)
2782 {
2783 	transport_free_pages(cmd);
2784 
2785 	if (cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
2786 		core_tmr_release_req(cmd->se_tmr_req);
2787 	if (cmd->t_task_cdb != cmd->__t_task_cdb)
2788 		kfree(cmd->t_task_cdb);
2789 }
2790 
2791 static void target_release_cmd_kref(struct kref *kref)
2792 {
2793 	struct se_cmd *se_cmd = container_of(kref, struct se_cmd, cmd_kref);
2794 	struct se_session *se_sess = se_cmd->se_sess;
2795 	struct completion *free_compl = se_cmd->free_compl;
2796 	struct completion *abrt_compl = se_cmd->abrt_compl;
2797 	unsigned long flags;
2798 
2799 	if (se_sess) {
2800 		spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2801 		list_del_init(&se_cmd->se_cmd_list);
2802 		spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2803 	}
2804 
2805 	target_free_cmd_mem(se_cmd);
2806 	se_cmd->se_tfo->release_cmd(se_cmd);
2807 	if (free_compl)
2808 		complete(free_compl);
2809 	if (abrt_compl)
2810 		complete(abrt_compl);
2811 
2812 	percpu_ref_put(&se_sess->cmd_count);
2813 }
2814 
2815 /**
2816  * target_put_sess_cmd - decrease the command reference count
2817  * @se_cmd:	command to drop a reference from
2818  *
2819  * Returns 1 if and only if this target_put_sess_cmd() call caused the
2820  * refcount to drop to zero. Returns zero otherwise.
2821  */
2822 int target_put_sess_cmd(struct se_cmd *se_cmd)
2823 {
2824 	return kref_put(&se_cmd->cmd_kref, target_release_cmd_kref);
2825 }
2826 EXPORT_SYMBOL(target_put_sess_cmd);
2827 
2828 static const char *data_dir_name(enum dma_data_direction d)
2829 {
2830 	switch (d) {
2831 	case DMA_BIDIRECTIONAL:	return "BIDI";
2832 	case DMA_TO_DEVICE:	return "WRITE";
2833 	case DMA_FROM_DEVICE:	return "READ";
2834 	case DMA_NONE:		return "NONE";
2835 	}
2836 
2837 	return "(?)";
2838 }
2839 
2840 static const char *cmd_state_name(enum transport_state_table t)
2841 {
2842 	switch (t) {
2843 	case TRANSPORT_NO_STATE:	return "NO_STATE";
2844 	case TRANSPORT_NEW_CMD:		return "NEW_CMD";
2845 	case TRANSPORT_WRITE_PENDING:	return "WRITE_PENDING";
2846 	case TRANSPORT_PROCESSING:	return "PROCESSING";
2847 	case TRANSPORT_COMPLETE:	return "COMPLETE";
2848 	case TRANSPORT_ISTATE_PROCESSING:
2849 					return "ISTATE_PROCESSING";
2850 	case TRANSPORT_COMPLETE_QF_WP:	return "COMPLETE_QF_WP";
2851 	case TRANSPORT_COMPLETE_QF_OK:	return "COMPLETE_QF_OK";
2852 	case TRANSPORT_COMPLETE_QF_ERR:	return "COMPLETE_QF_ERR";
2853 	}
2854 
2855 	return "(?)";
2856 }
2857 
2858 static void target_append_str(char **str, const char *txt)
2859 {
2860 	char *prev = *str;
2861 
2862 	*str = *str ? kasprintf(GFP_ATOMIC, "%s,%s", *str, txt) :
2863 		kstrdup(txt, GFP_ATOMIC);
2864 	kfree(prev);
2865 }
2866 
2867 /*
2868  * Convert a transport state bitmask into a string. The caller is
2869  * responsible for freeing the returned pointer.
2870  */
2871 static char *target_ts_to_str(u32 ts)
2872 {
2873 	char *str = NULL;
2874 
2875 	if (ts & CMD_T_ABORTED)
2876 		target_append_str(&str, "aborted");
2877 	if (ts & CMD_T_ACTIVE)
2878 		target_append_str(&str, "active");
2879 	if (ts & CMD_T_COMPLETE)
2880 		target_append_str(&str, "complete");
2881 	if (ts & CMD_T_SENT)
2882 		target_append_str(&str, "sent");
2883 	if (ts & CMD_T_STOP)
2884 		target_append_str(&str, "stop");
2885 	if (ts & CMD_T_FABRIC_STOP)
2886 		target_append_str(&str, "fabric_stop");
2887 
2888 	return str;
2889 }
2890 
2891 static const char *target_tmf_name(enum tcm_tmreq_table tmf)
2892 {
2893 	switch (tmf) {
2894 	case TMR_ABORT_TASK:		return "ABORT_TASK";
2895 	case TMR_ABORT_TASK_SET:	return "ABORT_TASK_SET";
2896 	case TMR_CLEAR_ACA:		return "CLEAR_ACA";
2897 	case TMR_CLEAR_TASK_SET:	return "CLEAR_TASK_SET";
2898 	case TMR_LUN_RESET:		return "LUN_RESET";
2899 	case TMR_TARGET_WARM_RESET:	return "TARGET_WARM_RESET";
2900 	case TMR_TARGET_COLD_RESET:	return "TARGET_COLD_RESET";
2901 	case TMR_UNKNOWN:		break;
2902 	}
2903 	return "(?)";
2904 }
2905 
2906 void target_show_cmd(const char *pfx, struct se_cmd *cmd)
2907 {
2908 	char *ts_str = target_ts_to_str(cmd->transport_state);
2909 	const u8 *cdb = cmd->t_task_cdb;
2910 	struct se_tmr_req *tmf = cmd->se_tmr_req;
2911 
2912 	if (!(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)) {
2913 		pr_debug("%scmd %#02x:%#02x with tag %#llx dir %s i_state %d t_state %s len %d refcnt %d transport_state %s\n",
2914 			 pfx, cdb[0], cdb[1], cmd->tag,
2915 			 data_dir_name(cmd->data_direction),
2916 			 cmd->se_tfo->get_cmd_state(cmd),
2917 			 cmd_state_name(cmd->t_state), cmd->data_length,
2918 			 kref_read(&cmd->cmd_kref), ts_str);
2919 	} else {
2920 		pr_debug("%stmf %s with tag %#llx ref_task_tag %#llx i_state %d t_state %s refcnt %d transport_state %s\n",
2921 			 pfx, target_tmf_name(tmf->function), cmd->tag,
2922 			 tmf->ref_task_tag, cmd->se_tfo->get_cmd_state(cmd),
2923 			 cmd_state_name(cmd->t_state),
2924 			 kref_read(&cmd->cmd_kref), ts_str);
2925 	}
2926 	kfree(ts_str);
2927 }
2928 EXPORT_SYMBOL(target_show_cmd);
2929 
2930 /**
2931  * target_sess_cmd_list_set_waiting - Set sess_tearing_down so no new commands are queued.
2932  * @se_sess:	session to flag
2933  */
2934 void target_sess_cmd_list_set_waiting(struct se_session *se_sess)
2935 {
2936 	unsigned long flags;
2937 
2938 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2939 	se_sess->sess_tearing_down = 1;
2940 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2941 
2942 	percpu_ref_kill(&se_sess->cmd_count);
2943 }
2944 EXPORT_SYMBOL(target_sess_cmd_list_set_waiting);
2945 
2946 /**
2947  * target_wait_for_sess_cmds - Wait for outstanding commands
2948  * @se_sess:    session to wait for active I/O
2949  */
2950 void target_wait_for_sess_cmds(struct se_session *se_sess)
2951 {
2952 	struct se_cmd *cmd;
2953 	int ret;
2954 
2955 	WARN_ON_ONCE(!se_sess->sess_tearing_down);
2956 
2957 	do {
2958 		ret = wait_event_timeout(se_sess->cmd_list_wq,
2959 				percpu_ref_is_zero(&se_sess->cmd_count),
2960 				180 * HZ);
2961 		list_for_each_entry(cmd, &se_sess->sess_cmd_list, se_cmd_list)
2962 			target_show_cmd("session shutdown: still waiting for ",
2963 					cmd);
2964 	} while (ret <= 0);
2965 }
2966 EXPORT_SYMBOL(target_wait_for_sess_cmds);
2967 
2968 /*
2969  * Prevent that new percpu_ref_tryget_live() calls succeed and wait until
2970  * all references to the LUN have been released. Called during LUN shutdown.
2971  */
2972 void transport_clear_lun_ref(struct se_lun *lun)
2973 {
2974 	percpu_ref_kill(&lun->lun_ref);
2975 	wait_for_completion(&lun->lun_shutdown_comp);
2976 }
2977 
2978 static bool
2979 __transport_wait_for_tasks(struct se_cmd *cmd, bool fabric_stop,
2980 			   bool *aborted, bool *tas, unsigned long *flags)
2981 	__releases(&cmd->t_state_lock)
2982 	__acquires(&cmd->t_state_lock)
2983 {
2984 
2985 	assert_spin_locked(&cmd->t_state_lock);
2986 	WARN_ON_ONCE(!irqs_disabled());
2987 
2988 	if (fabric_stop)
2989 		cmd->transport_state |= CMD_T_FABRIC_STOP;
2990 
2991 	if (cmd->transport_state & CMD_T_ABORTED)
2992 		*aborted = true;
2993 
2994 	if (cmd->transport_state & CMD_T_TAS)
2995 		*tas = true;
2996 
2997 	if (!(cmd->se_cmd_flags & SCF_SE_LUN_CMD) &&
2998 	    !(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
2999 		return false;
3000 
3001 	if (!(cmd->se_cmd_flags & SCF_SUPPORTED_SAM_OPCODE) &&
3002 	    !(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
3003 		return false;
3004 
3005 	if (!(cmd->transport_state & CMD_T_ACTIVE))
3006 		return false;
3007 
3008 	if (fabric_stop && *aborted)
3009 		return false;
3010 
3011 	cmd->transport_state |= CMD_T_STOP;
3012 
3013 	target_show_cmd("wait_for_tasks: Stopping ", cmd);
3014 
3015 	spin_unlock_irqrestore(&cmd->t_state_lock, *flags);
3016 
3017 	while (!wait_for_completion_timeout(&cmd->t_transport_stop_comp,
3018 					    180 * HZ))
3019 		target_show_cmd("wait for tasks: ", cmd);
3020 
3021 	spin_lock_irqsave(&cmd->t_state_lock, *flags);
3022 	cmd->transport_state &= ~(CMD_T_ACTIVE | CMD_T_STOP);
3023 
3024 	pr_debug("wait_for_tasks: Stopped wait_for_completion(&cmd->"
3025 		 "t_transport_stop_comp) for ITT: 0x%08llx\n", cmd->tag);
3026 
3027 	return true;
3028 }
3029 
3030 /**
3031  * transport_wait_for_tasks - set CMD_T_STOP and wait for t_transport_stop_comp
3032  * @cmd: command to wait on
3033  */
3034 bool transport_wait_for_tasks(struct se_cmd *cmd)
3035 {
3036 	unsigned long flags;
3037 	bool ret, aborted = false, tas = false;
3038 
3039 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3040 	ret = __transport_wait_for_tasks(cmd, false, &aborted, &tas, &flags);
3041 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3042 
3043 	return ret;
3044 }
3045 EXPORT_SYMBOL(transport_wait_for_tasks);
3046 
3047 struct sense_info {
3048 	u8 key;
3049 	u8 asc;
3050 	u8 ascq;
3051 	bool add_sector_info;
3052 };
3053 
3054 static const struct sense_info sense_info_table[] = {
3055 	[TCM_NO_SENSE] = {
3056 		.key = NOT_READY
3057 	},
3058 	[TCM_NON_EXISTENT_LUN] = {
3059 		.key = ILLEGAL_REQUEST,
3060 		.asc = 0x25 /* LOGICAL UNIT NOT SUPPORTED */
3061 	},
3062 	[TCM_UNSUPPORTED_SCSI_OPCODE] = {
3063 		.key = ILLEGAL_REQUEST,
3064 		.asc = 0x20, /* INVALID COMMAND OPERATION CODE */
3065 	},
3066 	[TCM_SECTOR_COUNT_TOO_MANY] = {
3067 		.key = ILLEGAL_REQUEST,
3068 		.asc = 0x20, /* INVALID COMMAND OPERATION CODE */
3069 	},
3070 	[TCM_UNKNOWN_MODE_PAGE] = {
3071 		.key = ILLEGAL_REQUEST,
3072 		.asc = 0x24, /* INVALID FIELD IN CDB */
3073 	},
3074 	[TCM_CHECK_CONDITION_ABORT_CMD] = {
3075 		.key = ABORTED_COMMAND,
3076 		.asc = 0x29, /* BUS DEVICE RESET FUNCTION OCCURRED */
3077 		.ascq = 0x03,
3078 	},
3079 	[TCM_INCORRECT_AMOUNT_OF_DATA] = {
3080 		.key = ABORTED_COMMAND,
3081 		.asc = 0x0c, /* WRITE ERROR */
3082 		.ascq = 0x0d, /* NOT ENOUGH UNSOLICITED DATA */
3083 	},
3084 	[TCM_INVALID_CDB_FIELD] = {
3085 		.key = ILLEGAL_REQUEST,
3086 		.asc = 0x24, /* INVALID FIELD IN CDB */
3087 	},
3088 	[TCM_INVALID_PARAMETER_LIST] = {
3089 		.key = ILLEGAL_REQUEST,
3090 		.asc = 0x26, /* INVALID FIELD IN PARAMETER LIST */
3091 	},
3092 	[TCM_TOO_MANY_TARGET_DESCS] = {
3093 		.key = ILLEGAL_REQUEST,
3094 		.asc = 0x26,
3095 		.ascq = 0x06, /* TOO MANY TARGET DESCRIPTORS */
3096 	},
3097 	[TCM_UNSUPPORTED_TARGET_DESC_TYPE_CODE] = {
3098 		.key = ILLEGAL_REQUEST,
3099 		.asc = 0x26,
3100 		.ascq = 0x07, /* UNSUPPORTED TARGET DESCRIPTOR TYPE CODE */
3101 	},
3102 	[TCM_TOO_MANY_SEGMENT_DESCS] = {
3103 		.key = ILLEGAL_REQUEST,
3104 		.asc = 0x26,
3105 		.ascq = 0x08, /* TOO MANY SEGMENT DESCRIPTORS */
3106 	},
3107 	[TCM_UNSUPPORTED_SEGMENT_DESC_TYPE_CODE] = {
3108 		.key = ILLEGAL_REQUEST,
3109 		.asc = 0x26,
3110 		.ascq = 0x09, /* UNSUPPORTED SEGMENT DESCRIPTOR TYPE CODE */
3111 	},
3112 	[TCM_PARAMETER_LIST_LENGTH_ERROR] = {
3113 		.key = ILLEGAL_REQUEST,
3114 		.asc = 0x1a, /* PARAMETER LIST LENGTH ERROR */
3115 	},
3116 	[TCM_UNEXPECTED_UNSOLICITED_DATA] = {
3117 		.key = ILLEGAL_REQUEST,
3118 		.asc = 0x0c, /* WRITE ERROR */
3119 		.ascq = 0x0c, /* UNEXPECTED_UNSOLICITED_DATA */
3120 	},
3121 	[TCM_SERVICE_CRC_ERROR] = {
3122 		.key = ABORTED_COMMAND,
3123 		.asc = 0x47, /* PROTOCOL SERVICE CRC ERROR */
3124 		.ascq = 0x05, /* N/A */
3125 	},
3126 	[TCM_SNACK_REJECTED] = {
3127 		.key = ABORTED_COMMAND,
3128 		.asc = 0x11, /* READ ERROR */
3129 		.ascq = 0x13, /* FAILED RETRANSMISSION REQUEST */
3130 	},
3131 	[TCM_WRITE_PROTECTED] = {
3132 		.key = DATA_PROTECT,
3133 		.asc = 0x27, /* WRITE PROTECTED */
3134 	},
3135 	[TCM_ADDRESS_OUT_OF_RANGE] = {
3136 		.key = ILLEGAL_REQUEST,
3137 		.asc = 0x21, /* LOGICAL BLOCK ADDRESS OUT OF RANGE */
3138 	},
3139 	[TCM_CHECK_CONDITION_UNIT_ATTENTION] = {
3140 		.key = UNIT_ATTENTION,
3141 	},
3142 	[TCM_CHECK_CONDITION_NOT_READY] = {
3143 		.key = NOT_READY,
3144 	},
3145 	[TCM_MISCOMPARE_VERIFY] = {
3146 		.key = MISCOMPARE,
3147 		.asc = 0x1d, /* MISCOMPARE DURING VERIFY OPERATION */
3148 		.ascq = 0x00,
3149 	},
3150 	[TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED] = {
3151 		.key = ABORTED_COMMAND,
3152 		.asc = 0x10,
3153 		.ascq = 0x01, /* LOGICAL BLOCK GUARD CHECK FAILED */
3154 		.add_sector_info = true,
3155 	},
3156 	[TCM_LOGICAL_BLOCK_APP_TAG_CHECK_FAILED] = {
3157 		.key = ABORTED_COMMAND,
3158 		.asc = 0x10,
3159 		.ascq = 0x02, /* LOGICAL BLOCK APPLICATION TAG CHECK FAILED */
3160 		.add_sector_info = true,
3161 	},
3162 	[TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED] = {
3163 		.key = ABORTED_COMMAND,
3164 		.asc = 0x10,
3165 		.ascq = 0x03, /* LOGICAL BLOCK REFERENCE TAG CHECK FAILED */
3166 		.add_sector_info = true,
3167 	},
3168 	[TCM_COPY_TARGET_DEVICE_NOT_REACHABLE] = {
3169 		.key = COPY_ABORTED,
3170 		.asc = 0x0d,
3171 		.ascq = 0x02, /* COPY TARGET DEVICE NOT REACHABLE */
3172 
3173 	},
3174 	[TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE] = {
3175 		/*
3176 		 * Returning ILLEGAL REQUEST would cause immediate IO errors on
3177 		 * Solaris initiators.  Returning NOT READY instead means the
3178 		 * operations will be retried a finite number of times and we
3179 		 * can survive intermittent errors.
3180 		 */
3181 		.key = NOT_READY,
3182 		.asc = 0x08, /* LOGICAL UNIT COMMUNICATION FAILURE */
3183 	},
3184 	[TCM_INSUFFICIENT_REGISTRATION_RESOURCES] = {
3185 		/*
3186 		 * From spc4r22 section5.7.7,5.7.8
3187 		 * If a PERSISTENT RESERVE OUT command with a REGISTER service action
3188 		 * or a REGISTER AND IGNORE EXISTING KEY service action or
3189 		 * REGISTER AND MOVE service actionis attempted,
3190 		 * but there are insufficient device server resources to complete the
3191 		 * operation, then the command shall be terminated with CHECK CONDITION
3192 		 * status, with the sense key set to ILLEGAL REQUEST,and the additonal
3193 		 * sense code set to INSUFFICIENT REGISTRATION RESOURCES.
3194 		 */
3195 		.key = ILLEGAL_REQUEST,
3196 		.asc = 0x55,
3197 		.ascq = 0x04, /* INSUFFICIENT REGISTRATION RESOURCES */
3198 	},
3199 };
3200 
3201 /**
3202  * translate_sense_reason - translate a sense reason into T10 key, asc and ascq
3203  * @cmd: SCSI command in which the resulting sense buffer or SCSI status will
3204  *   be stored.
3205  * @reason: LIO sense reason code. If this argument has the value
3206  *   TCM_CHECK_CONDITION_UNIT_ATTENTION, try to dequeue a unit attention. If
3207  *   dequeuing a unit attention fails due to multiple commands being processed
3208  *   concurrently, set the command status to BUSY.
3209  *
3210  * Return: 0 upon success or -EINVAL if the sense buffer is too small.
3211  */
3212 static void translate_sense_reason(struct se_cmd *cmd, sense_reason_t reason)
3213 {
3214 	const struct sense_info *si;
3215 	u8 *buffer = cmd->sense_buffer;
3216 	int r = (__force int)reason;
3217 	u8 key, asc, ascq;
3218 	bool desc_format = target_sense_desc_format(cmd->se_dev);
3219 
3220 	if (r < ARRAY_SIZE(sense_info_table) && sense_info_table[r].key)
3221 		si = &sense_info_table[r];
3222 	else
3223 		si = &sense_info_table[(__force int)
3224 				       TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE];
3225 
3226 	key = si->key;
3227 	if (reason == TCM_CHECK_CONDITION_UNIT_ATTENTION) {
3228 		if (!core_scsi3_ua_for_check_condition(cmd, &key, &asc,
3229 						       &ascq)) {
3230 			cmd->scsi_status = SAM_STAT_BUSY;
3231 			return;
3232 		}
3233 	} else if (si->asc == 0) {
3234 		WARN_ON_ONCE(cmd->scsi_asc == 0);
3235 		asc = cmd->scsi_asc;
3236 		ascq = cmd->scsi_ascq;
3237 	} else {
3238 		asc = si->asc;
3239 		ascq = si->ascq;
3240 	}
3241 
3242 	cmd->se_cmd_flags |= SCF_EMULATED_TASK_SENSE;
3243 	cmd->scsi_status = SAM_STAT_CHECK_CONDITION;
3244 	cmd->scsi_sense_length  = TRANSPORT_SENSE_BUFFER;
3245 	scsi_build_sense_buffer(desc_format, buffer, key, asc, ascq);
3246 	if (si->add_sector_info)
3247 		WARN_ON_ONCE(scsi_set_sense_information(buffer,
3248 							cmd->scsi_sense_length,
3249 							cmd->bad_sector) < 0);
3250 }
3251 
3252 int
3253 transport_send_check_condition_and_sense(struct se_cmd *cmd,
3254 		sense_reason_t reason, int from_transport)
3255 {
3256 	unsigned long flags;
3257 
3258 	WARN_ON_ONCE(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB);
3259 
3260 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3261 	if (cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION) {
3262 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3263 		return 0;
3264 	}
3265 	cmd->se_cmd_flags |= SCF_SENT_CHECK_CONDITION;
3266 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3267 
3268 	if (!from_transport)
3269 		translate_sense_reason(cmd, reason);
3270 
3271 	trace_target_cmd_complete(cmd);
3272 	return cmd->se_tfo->queue_status(cmd);
3273 }
3274 EXPORT_SYMBOL(transport_send_check_condition_and_sense);
3275 
3276 static void target_tmr_work(struct work_struct *work)
3277 {
3278 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
3279 	struct se_device *dev = cmd->se_dev;
3280 	struct se_tmr_req *tmr = cmd->se_tmr_req;
3281 	int ret;
3282 
3283 	if (cmd->transport_state & CMD_T_ABORTED)
3284 		goto aborted;
3285 
3286 	switch (tmr->function) {
3287 	case TMR_ABORT_TASK:
3288 		core_tmr_abort_task(dev, tmr, cmd->se_sess);
3289 		break;
3290 	case TMR_ABORT_TASK_SET:
3291 	case TMR_CLEAR_ACA:
3292 	case TMR_CLEAR_TASK_SET:
3293 		tmr->response = TMR_TASK_MGMT_FUNCTION_NOT_SUPPORTED;
3294 		break;
3295 	case TMR_LUN_RESET:
3296 		ret = core_tmr_lun_reset(dev, tmr, NULL, NULL);
3297 		tmr->response = (!ret) ? TMR_FUNCTION_COMPLETE :
3298 					 TMR_FUNCTION_REJECTED;
3299 		if (tmr->response == TMR_FUNCTION_COMPLETE) {
3300 			target_ua_allocate_lun(cmd->se_sess->se_node_acl,
3301 					       cmd->orig_fe_lun, 0x29,
3302 					       ASCQ_29H_BUS_DEVICE_RESET_FUNCTION_OCCURRED);
3303 		}
3304 		break;
3305 	case TMR_TARGET_WARM_RESET:
3306 		tmr->response = TMR_FUNCTION_REJECTED;
3307 		break;
3308 	case TMR_TARGET_COLD_RESET:
3309 		tmr->response = TMR_FUNCTION_REJECTED;
3310 		break;
3311 	default:
3312 		pr_err("Unknown TMR function: 0x%02x.\n",
3313 				tmr->function);
3314 		tmr->response = TMR_FUNCTION_REJECTED;
3315 		break;
3316 	}
3317 
3318 	if (cmd->transport_state & CMD_T_ABORTED)
3319 		goto aborted;
3320 
3321 	cmd->se_tfo->queue_tm_rsp(cmd);
3322 
3323 	transport_cmd_check_stop_to_fabric(cmd);
3324 	return;
3325 
3326 aborted:
3327 	target_handle_abort(cmd);
3328 }
3329 
3330 int transport_generic_handle_tmr(
3331 	struct se_cmd *cmd)
3332 {
3333 	unsigned long flags;
3334 	bool aborted = false;
3335 
3336 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3337 	if (cmd->transport_state & CMD_T_ABORTED) {
3338 		aborted = true;
3339 	} else {
3340 		cmd->t_state = TRANSPORT_ISTATE_PROCESSING;
3341 		cmd->transport_state |= CMD_T_ACTIVE;
3342 	}
3343 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3344 
3345 	if (aborted) {
3346 		pr_warn_ratelimited("handle_tmr caught CMD_T_ABORTED TMR %d ref_tag: %llu tag: %llu\n",
3347 				    cmd->se_tmr_req->function,
3348 				    cmd->se_tmr_req->ref_task_tag, cmd->tag);
3349 		target_handle_abort(cmd);
3350 		return 0;
3351 	}
3352 
3353 	INIT_WORK(&cmd->work, target_tmr_work);
3354 	schedule_work(&cmd->work);
3355 	return 0;
3356 }
3357 EXPORT_SYMBOL(transport_generic_handle_tmr);
3358 
3359 bool
3360 target_check_wce(struct se_device *dev)
3361 {
3362 	bool wce = false;
3363 
3364 	if (dev->transport->get_write_cache)
3365 		wce = dev->transport->get_write_cache(dev);
3366 	else if (dev->dev_attrib.emulate_write_cache > 0)
3367 		wce = true;
3368 
3369 	return wce;
3370 }
3371 
3372 bool
3373 target_check_fua(struct se_device *dev)
3374 {
3375 	return target_check_wce(dev) && dev->dev_attrib.emulate_fua_write > 0;
3376 }
3377