xref: /openbmc/linux/drivers/target/target_core_transport.c (revision bd329f028f1cd51c7623c326147af07c6d832193)
1 /*******************************************************************************
2  * Filename:  target_core_transport.c
3  *
4  * This file contains the Generic Target Engine Core.
5  *
6  * (c) Copyright 2002-2013 Datera, Inc.
7  *
8  * Nicholas A. Bellinger <nab@kernel.org>
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License as published by
12  * the Free Software Foundation; either version 2 of the License, or
13  * (at your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18  * GNU General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with this program; if not, write to the Free Software
22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
23  *
24  ******************************************************************************/
25 
26 #include <linux/net.h>
27 #include <linux/delay.h>
28 #include <linux/string.h>
29 #include <linux/timer.h>
30 #include <linux/slab.h>
31 #include <linux/spinlock.h>
32 #include <linux/kthread.h>
33 #include <linux/in.h>
34 #include <linux/cdrom.h>
35 #include <linux/module.h>
36 #include <linux/ratelimit.h>
37 #include <linux/vmalloc.h>
38 #include <asm/unaligned.h>
39 #include <net/sock.h>
40 #include <net/tcp.h>
41 #include <scsi/scsi_proto.h>
42 #include <scsi/scsi_common.h>
43 
44 #include <target/target_core_base.h>
45 #include <target/target_core_backend.h>
46 #include <target/target_core_fabric.h>
47 
48 #include "target_core_internal.h"
49 #include "target_core_alua.h"
50 #include "target_core_pr.h"
51 #include "target_core_ua.h"
52 
53 #define CREATE_TRACE_POINTS
54 #include <trace/events/target.h>
55 
56 static struct workqueue_struct *target_completion_wq;
57 static struct kmem_cache *se_sess_cache;
58 struct kmem_cache *se_ua_cache;
59 struct kmem_cache *t10_pr_reg_cache;
60 struct kmem_cache *t10_alua_lu_gp_cache;
61 struct kmem_cache *t10_alua_lu_gp_mem_cache;
62 struct kmem_cache *t10_alua_tg_pt_gp_cache;
63 struct kmem_cache *t10_alua_lba_map_cache;
64 struct kmem_cache *t10_alua_lba_map_mem_cache;
65 
66 static void transport_complete_task_attr(struct se_cmd *cmd);
67 static int translate_sense_reason(struct se_cmd *cmd, sense_reason_t reason);
68 static void transport_handle_queue_full(struct se_cmd *cmd,
69 		struct se_device *dev, int err, bool write_pending);
70 static void target_complete_ok_work(struct work_struct *work);
71 
72 int init_se_kmem_caches(void)
73 {
74 	se_sess_cache = kmem_cache_create("se_sess_cache",
75 			sizeof(struct se_session), __alignof__(struct se_session),
76 			0, NULL);
77 	if (!se_sess_cache) {
78 		pr_err("kmem_cache_create() for struct se_session"
79 				" failed\n");
80 		goto out;
81 	}
82 	se_ua_cache = kmem_cache_create("se_ua_cache",
83 			sizeof(struct se_ua), __alignof__(struct se_ua),
84 			0, NULL);
85 	if (!se_ua_cache) {
86 		pr_err("kmem_cache_create() for struct se_ua failed\n");
87 		goto out_free_sess_cache;
88 	}
89 	t10_pr_reg_cache = kmem_cache_create("t10_pr_reg_cache",
90 			sizeof(struct t10_pr_registration),
91 			__alignof__(struct t10_pr_registration), 0, NULL);
92 	if (!t10_pr_reg_cache) {
93 		pr_err("kmem_cache_create() for struct t10_pr_registration"
94 				" failed\n");
95 		goto out_free_ua_cache;
96 	}
97 	t10_alua_lu_gp_cache = kmem_cache_create("t10_alua_lu_gp_cache",
98 			sizeof(struct t10_alua_lu_gp), __alignof__(struct t10_alua_lu_gp),
99 			0, NULL);
100 	if (!t10_alua_lu_gp_cache) {
101 		pr_err("kmem_cache_create() for t10_alua_lu_gp_cache"
102 				" failed\n");
103 		goto out_free_pr_reg_cache;
104 	}
105 	t10_alua_lu_gp_mem_cache = kmem_cache_create("t10_alua_lu_gp_mem_cache",
106 			sizeof(struct t10_alua_lu_gp_member),
107 			__alignof__(struct t10_alua_lu_gp_member), 0, NULL);
108 	if (!t10_alua_lu_gp_mem_cache) {
109 		pr_err("kmem_cache_create() for t10_alua_lu_gp_mem_"
110 				"cache failed\n");
111 		goto out_free_lu_gp_cache;
112 	}
113 	t10_alua_tg_pt_gp_cache = kmem_cache_create("t10_alua_tg_pt_gp_cache",
114 			sizeof(struct t10_alua_tg_pt_gp),
115 			__alignof__(struct t10_alua_tg_pt_gp), 0, NULL);
116 	if (!t10_alua_tg_pt_gp_cache) {
117 		pr_err("kmem_cache_create() for t10_alua_tg_pt_gp_"
118 				"cache failed\n");
119 		goto out_free_lu_gp_mem_cache;
120 	}
121 	t10_alua_lba_map_cache = kmem_cache_create(
122 			"t10_alua_lba_map_cache",
123 			sizeof(struct t10_alua_lba_map),
124 			__alignof__(struct t10_alua_lba_map), 0, NULL);
125 	if (!t10_alua_lba_map_cache) {
126 		pr_err("kmem_cache_create() for t10_alua_lba_map_"
127 				"cache failed\n");
128 		goto out_free_tg_pt_gp_cache;
129 	}
130 	t10_alua_lba_map_mem_cache = kmem_cache_create(
131 			"t10_alua_lba_map_mem_cache",
132 			sizeof(struct t10_alua_lba_map_member),
133 			__alignof__(struct t10_alua_lba_map_member), 0, NULL);
134 	if (!t10_alua_lba_map_mem_cache) {
135 		pr_err("kmem_cache_create() for t10_alua_lba_map_mem_"
136 				"cache failed\n");
137 		goto out_free_lba_map_cache;
138 	}
139 
140 	target_completion_wq = alloc_workqueue("target_completion",
141 					       WQ_MEM_RECLAIM, 0);
142 	if (!target_completion_wq)
143 		goto out_free_lba_map_mem_cache;
144 
145 	return 0;
146 
147 out_free_lba_map_mem_cache:
148 	kmem_cache_destroy(t10_alua_lba_map_mem_cache);
149 out_free_lba_map_cache:
150 	kmem_cache_destroy(t10_alua_lba_map_cache);
151 out_free_tg_pt_gp_cache:
152 	kmem_cache_destroy(t10_alua_tg_pt_gp_cache);
153 out_free_lu_gp_mem_cache:
154 	kmem_cache_destroy(t10_alua_lu_gp_mem_cache);
155 out_free_lu_gp_cache:
156 	kmem_cache_destroy(t10_alua_lu_gp_cache);
157 out_free_pr_reg_cache:
158 	kmem_cache_destroy(t10_pr_reg_cache);
159 out_free_ua_cache:
160 	kmem_cache_destroy(se_ua_cache);
161 out_free_sess_cache:
162 	kmem_cache_destroy(se_sess_cache);
163 out:
164 	return -ENOMEM;
165 }
166 
167 void release_se_kmem_caches(void)
168 {
169 	destroy_workqueue(target_completion_wq);
170 	kmem_cache_destroy(se_sess_cache);
171 	kmem_cache_destroy(se_ua_cache);
172 	kmem_cache_destroy(t10_pr_reg_cache);
173 	kmem_cache_destroy(t10_alua_lu_gp_cache);
174 	kmem_cache_destroy(t10_alua_lu_gp_mem_cache);
175 	kmem_cache_destroy(t10_alua_tg_pt_gp_cache);
176 	kmem_cache_destroy(t10_alua_lba_map_cache);
177 	kmem_cache_destroy(t10_alua_lba_map_mem_cache);
178 }
179 
180 /* This code ensures unique mib indexes are handed out. */
181 static DEFINE_SPINLOCK(scsi_mib_index_lock);
182 static u32 scsi_mib_index[SCSI_INDEX_TYPE_MAX];
183 
184 /*
185  * Allocate a new row index for the entry type specified
186  */
187 u32 scsi_get_new_index(scsi_index_t type)
188 {
189 	u32 new_index;
190 
191 	BUG_ON((type < 0) || (type >= SCSI_INDEX_TYPE_MAX));
192 
193 	spin_lock(&scsi_mib_index_lock);
194 	new_index = ++scsi_mib_index[type];
195 	spin_unlock(&scsi_mib_index_lock);
196 
197 	return new_index;
198 }
199 
200 void transport_subsystem_check_init(void)
201 {
202 	int ret;
203 	static int sub_api_initialized;
204 
205 	if (sub_api_initialized)
206 		return;
207 
208 	ret = request_module("target_core_iblock");
209 	if (ret != 0)
210 		pr_err("Unable to load target_core_iblock\n");
211 
212 	ret = request_module("target_core_file");
213 	if (ret != 0)
214 		pr_err("Unable to load target_core_file\n");
215 
216 	ret = request_module("target_core_pscsi");
217 	if (ret != 0)
218 		pr_err("Unable to load target_core_pscsi\n");
219 
220 	ret = request_module("target_core_user");
221 	if (ret != 0)
222 		pr_err("Unable to load target_core_user\n");
223 
224 	sub_api_initialized = 1;
225 }
226 
227 struct se_session *transport_init_session(enum target_prot_op sup_prot_ops)
228 {
229 	struct se_session *se_sess;
230 
231 	se_sess = kmem_cache_zalloc(se_sess_cache, GFP_KERNEL);
232 	if (!se_sess) {
233 		pr_err("Unable to allocate struct se_session from"
234 				" se_sess_cache\n");
235 		return ERR_PTR(-ENOMEM);
236 	}
237 	INIT_LIST_HEAD(&se_sess->sess_list);
238 	INIT_LIST_HEAD(&se_sess->sess_acl_list);
239 	INIT_LIST_HEAD(&se_sess->sess_cmd_list);
240 	INIT_LIST_HEAD(&se_sess->sess_wait_list);
241 	spin_lock_init(&se_sess->sess_cmd_lock);
242 	se_sess->sup_prot_ops = sup_prot_ops;
243 
244 	return se_sess;
245 }
246 EXPORT_SYMBOL(transport_init_session);
247 
248 int transport_alloc_session_tags(struct se_session *se_sess,
249 			         unsigned int tag_num, unsigned int tag_size)
250 {
251 	int rc;
252 
253 	se_sess->sess_cmd_map = kzalloc(tag_num * tag_size,
254 					GFP_KERNEL | __GFP_NOWARN | __GFP_RETRY_MAYFAIL);
255 	if (!se_sess->sess_cmd_map) {
256 		se_sess->sess_cmd_map = vzalloc(tag_num * tag_size);
257 		if (!se_sess->sess_cmd_map) {
258 			pr_err("Unable to allocate se_sess->sess_cmd_map\n");
259 			return -ENOMEM;
260 		}
261 	}
262 
263 	rc = percpu_ida_init(&se_sess->sess_tag_pool, tag_num);
264 	if (rc < 0) {
265 		pr_err("Unable to init se_sess->sess_tag_pool,"
266 			" tag_num: %u\n", tag_num);
267 		kvfree(se_sess->sess_cmd_map);
268 		se_sess->sess_cmd_map = NULL;
269 		return -ENOMEM;
270 	}
271 
272 	return 0;
273 }
274 EXPORT_SYMBOL(transport_alloc_session_tags);
275 
276 struct se_session *transport_init_session_tags(unsigned int tag_num,
277 					       unsigned int tag_size,
278 					       enum target_prot_op sup_prot_ops)
279 {
280 	struct se_session *se_sess;
281 	int rc;
282 
283 	if (tag_num != 0 && !tag_size) {
284 		pr_err("init_session_tags called with percpu-ida tag_num:"
285 		       " %u, but zero tag_size\n", tag_num);
286 		return ERR_PTR(-EINVAL);
287 	}
288 	if (!tag_num && tag_size) {
289 		pr_err("init_session_tags called with percpu-ida tag_size:"
290 		       " %u, but zero tag_num\n", tag_size);
291 		return ERR_PTR(-EINVAL);
292 	}
293 
294 	se_sess = transport_init_session(sup_prot_ops);
295 	if (IS_ERR(se_sess))
296 		return se_sess;
297 
298 	rc = transport_alloc_session_tags(se_sess, tag_num, tag_size);
299 	if (rc < 0) {
300 		transport_free_session(se_sess);
301 		return ERR_PTR(-ENOMEM);
302 	}
303 
304 	return se_sess;
305 }
306 EXPORT_SYMBOL(transport_init_session_tags);
307 
308 /*
309  * Called with spin_lock_irqsave(&struct se_portal_group->session_lock called.
310  */
311 void __transport_register_session(
312 	struct se_portal_group *se_tpg,
313 	struct se_node_acl *se_nacl,
314 	struct se_session *se_sess,
315 	void *fabric_sess_ptr)
316 {
317 	const struct target_core_fabric_ops *tfo = se_tpg->se_tpg_tfo;
318 	unsigned char buf[PR_REG_ISID_LEN];
319 
320 	se_sess->se_tpg = se_tpg;
321 	se_sess->fabric_sess_ptr = fabric_sess_ptr;
322 	/*
323 	 * Used by struct se_node_acl's under ConfigFS to locate active se_session-t
324 	 *
325 	 * Only set for struct se_session's that will actually be moving I/O.
326 	 * eg: *NOT* discovery sessions.
327 	 */
328 	if (se_nacl) {
329 		/*
330 		 *
331 		 * Determine if fabric allows for T10-PI feature bits exposed to
332 		 * initiators for device backends with !dev->dev_attrib.pi_prot_type.
333 		 *
334 		 * If so, then always save prot_type on a per se_node_acl node
335 		 * basis and re-instate the previous sess_prot_type to avoid
336 		 * disabling PI from below any previously initiator side
337 		 * registered LUNs.
338 		 */
339 		if (se_nacl->saved_prot_type)
340 			se_sess->sess_prot_type = se_nacl->saved_prot_type;
341 		else if (tfo->tpg_check_prot_fabric_only)
342 			se_sess->sess_prot_type = se_nacl->saved_prot_type =
343 					tfo->tpg_check_prot_fabric_only(se_tpg);
344 		/*
345 		 * If the fabric module supports an ISID based TransportID,
346 		 * save this value in binary from the fabric I_T Nexus now.
347 		 */
348 		if (se_tpg->se_tpg_tfo->sess_get_initiator_sid != NULL) {
349 			memset(&buf[0], 0, PR_REG_ISID_LEN);
350 			se_tpg->se_tpg_tfo->sess_get_initiator_sid(se_sess,
351 					&buf[0], PR_REG_ISID_LEN);
352 			se_sess->sess_bin_isid = get_unaligned_be64(&buf[0]);
353 		}
354 
355 		spin_lock_irq(&se_nacl->nacl_sess_lock);
356 		/*
357 		 * The se_nacl->nacl_sess pointer will be set to the
358 		 * last active I_T Nexus for each struct se_node_acl.
359 		 */
360 		se_nacl->nacl_sess = se_sess;
361 
362 		list_add_tail(&se_sess->sess_acl_list,
363 			      &se_nacl->acl_sess_list);
364 		spin_unlock_irq(&se_nacl->nacl_sess_lock);
365 	}
366 	list_add_tail(&se_sess->sess_list, &se_tpg->tpg_sess_list);
367 
368 	pr_debug("TARGET_CORE[%s]: Registered fabric_sess_ptr: %p\n",
369 		se_tpg->se_tpg_tfo->get_fabric_name(), se_sess->fabric_sess_ptr);
370 }
371 EXPORT_SYMBOL(__transport_register_session);
372 
373 void transport_register_session(
374 	struct se_portal_group *se_tpg,
375 	struct se_node_acl *se_nacl,
376 	struct se_session *se_sess,
377 	void *fabric_sess_ptr)
378 {
379 	unsigned long flags;
380 
381 	spin_lock_irqsave(&se_tpg->session_lock, flags);
382 	__transport_register_session(se_tpg, se_nacl, se_sess, fabric_sess_ptr);
383 	spin_unlock_irqrestore(&se_tpg->session_lock, flags);
384 }
385 EXPORT_SYMBOL(transport_register_session);
386 
387 struct se_session *
388 target_alloc_session(struct se_portal_group *tpg,
389 		     unsigned int tag_num, unsigned int tag_size,
390 		     enum target_prot_op prot_op,
391 		     const char *initiatorname, void *private,
392 		     int (*callback)(struct se_portal_group *,
393 				     struct se_session *, void *))
394 {
395 	struct se_session *sess;
396 
397 	/*
398 	 * If the fabric driver is using percpu-ida based pre allocation
399 	 * of I/O descriptor tags, go ahead and perform that setup now..
400 	 */
401 	if (tag_num != 0)
402 		sess = transport_init_session_tags(tag_num, tag_size, prot_op);
403 	else
404 		sess = transport_init_session(prot_op);
405 
406 	if (IS_ERR(sess))
407 		return sess;
408 
409 	sess->se_node_acl = core_tpg_check_initiator_node_acl(tpg,
410 					(unsigned char *)initiatorname);
411 	if (!sess->se_node_acl) {
412 		transport_free_session(sess);
413 		return ERR_PTR(-EACCES);
414 	}
415 	/*
416 	 * Go ahead and perform any remaining fabric setup that is
417 	 * required before transport_register_session().
418 	 */
419 	if (callback != NULL) {
420 		int rc = callback(tpg, sess, private);
421 		if (rc) {
422 			transport_free_session(sess);
423 			return ERR_PTR(rc);
424 		}
425 	}
426 
427 	transport_register_session(tpg, sess->se_node_acl, sess, private);
428 	return sess;
429 }
430 EXPORT_SYMBOL(target_alloc_session);
431 
432 ssize_t target_show_dynamic_sessions(struct se_portal_group *se_tpg, char *page)
433 {
434 	struct se_session *se_sess;
435 	ssize_t len = 0;
436 
437 	spin_lock_bh(&se_tpg->session_lock);
438 	list_for_each_entry(se_sess, &se_tpg->tpg_sess_list, sess_list) {
439 		if (!se_sess->se_node_acl)
440 			continue;
441 		if (!se_sess->se_node_acl->dynamic_node_acl)
442 			continue;
443 		if (strlen(se_sess->se_node_acl->initiatorname) + 1 + len > PAGE_SIZE)
444 			break;
445 
446 		len += snprintf(page + len, PAGE_SIZE - len, "%s\n",
447 				se_sess->se_node_acl->initiatorname);
448 		len += 1; /* Include NULL terminator */
449 	}
450 	spin_unlock_bh(&se_tpg->session_lock);
451 
452 	return len;
453 }
454 EXPORT_SYMBOL(target_show_dynamic_sessions);
455 
456 static void target_complete_nacl(struct kref *kref)
457 {
458 	struct se_node_acl *nacl = container_of(kref,
459 				struct se_node_acl, acl_kref);
460 	struct se_portal_group *se_tpg = nacl->se_tpg;
461 
462 	if (!nacl->dynamic_stop) {
463 		complete(&nacl->acl_free_comp);
464 		return;
465 	}
466 
467 	mutex_lock(&se_tpg->acl_node_mutex);
468 	list_del_init(&nacl->acl_list);
469 	mutex_unlock(&se_tpg->acl_node_mutex);
470 
471 	core_tpg_wait_for_nacl_pr_ref(nacl);
472 	core_free_device_list_for_node(nacl, se_tpg);
473 	kfree(nacl);
474 }
475 
476 void target_put_nacl(struct se_node_acl *nacl)
477 {
478 	kref_put(&nacl->acl_kref, target_complete_nacl);
479 }
480 EXPORT_SYMBOL(target_put_nacl);
481 
482 void transport_deregister_session_configfs(struct se_session *se_sess)
483 {
484 	struct se_node_acl *se_nacl;
485 	unsigned long flags;
486 	/*
487 	 * Used by struct se_node_acl's under ConfigFS to locate active struct se_session
488 	 */
489 	se_nacl = se_sess->se_node_acl;
490 	if (se_nacl) {
491 		spin_lock_irqsave(&se_nacl->nacl_sess_lock, flags);
492 		if (!list_empty(&se_sess->sess_acl_list))
493 			list_del_init(&se_sess->sess_acl_list);
494 		/*
495 		 * If the session list is empty, then clear the pointer.
496 		 * Otherwise, set the struct se_session pointer from the tail
497 		 * element of the per struct se_node_acl active session list.
498 		 */
499 		if (list_empty(&se_nacl->acl_sess_list))
500 			se_nacl->nacl_sess = NULL;
501 		else {
502 			se_nacl->nacl_sess = container_of(
503 					se_nacl->acl_sess_list.prev,
504 					struct se_session, sess_acl_list);
505 		}
506 		spin_unlock_irqrestore(&se_nacl->nacl_sess_lock, flags);
507 	}
508 }
509 EXPORT_SYMBOL(transport_deregister_session_configfs);
510 
511 void transport_free_session(struct se_session *se_sess)
512 {
513 	struct se_node_acl *se_nacl = se_sess->se_node_acl;
514 
515 	/*
516 	 * Drop the se_node_acl->nacl_kref obtained from within
517 	 * core_tpg_get_initiator_node_acl().
518 	 */
519 	if (se_nacl) {
520 		struct se_portal_group *se_tpg = se_nacl->se_tpg;
521 		const struct target_core_fabric_ops *se_tfo = se_tpg->se_tpg_tfo;
522 		unsigned long flags;
523 
524 		se_sess->se_node_acl = NULL;
525 
526 		/*
527 		 * Also determine if we need to drop the extra ->cmd_kref if
528 		 * it had been previously dynamically generated, and
529 		 * the endpoint is not caching dynamic ACLs.
530 		 */
531 		mutex_lock(&se_tpg->acl_node_mutex);
532 		if (se_nacl->dynamic_node_acl &&
533 		    !se_tfo->tpg_check_demo_mode_cache(se_tpg)) {
534 			spin_lock_irqsave(&se_nacl->nacl_sess_lock, flags);
535 			if (list_empty(&se_nacl->acl_sess_list))
536 				se_nacl->dynamic_stop = true;
537 			spin_unlock_irqrestore(&se_nacl->nacl_sess_lock, flags);
538 
539 			if (se_nacl->dynamic_stop)
540 				list_del_init(&se_nacl->acl_list);
541 		}
542 		mutex_unlock(&se_tpg->acl_node_mutex);
543 
544 		if (se_nacl->dynamic_stop)
545 			target_put_nacl(se_nacl);
546 
547 		target_put_nacl(se_nacl);
548 	}
549 	if (se_sess->sess_cmd_map) {
550 		percpu_ida_destroy(&se_sess->sess_tag_pool);
551 		kvfree(se_sess->sess_cmd_map);
552 	}
553 	kmem_cache_free(se_sess_cache, se_sess);
554 }
555 EXPORT_SYMBOL(transport_free_session);
556 
557 void transport_deregister_session(struct se_session *se_sess)
558 {
559 	struct se_portal_group *se_tpg = se_sess->se_tpg;
560 	unsigned long flags;
561 
562 	if (!se_tpg) {
563 		transport_free_session(se_sess);
564 		return;
565 	}
566 
567 	spin_lock_irqsave(&se_tpg->session_lock, flags);
568 	list_del(&se_sess->sess_list);
569 	se_sess->se_tpg = NULL;
570 	se_sess->fabric_sess_ptr = NULL;
571 	spin_unlock_irqrestore(&se_tpg->session_lock, flags);
572 
573 	pr_debug("TARGET_CORE[%s]: Deregistered fabric_sess\n",
574 		se_tpg->se_tpg_tfo->get_fabric_name());
575 	/*
576 	 * If last kref is dropping now for an explicit NodeACL, awake sleeping
577 	 * ->acl_free_comp caller to wakeup configfs se_node_acl->acl_group
578 	 * removal context from within transport_free_session() code.
579 	 *
580 	 * For dynamic ACL, target_put_nacl() uses target_complete_nacl()
581 	 * to release all remaining generate_node_acl=1 created ACL resources.
582 	 */
583 
584 	transport_free_session(se_sess);
585 }
586 EXPORT_SYMBOL(transport_deregister_session);
587 
588 static void target_remove_from_state_list(struct se_cmd *cmd)
589 {
590 	struct se_device *dev = cmd->se_dev;
591 	unsigned long flags;
592 
593 	if (!dev)
594 		return;
595 
596 	spin_lock_irqsave(&dev->execute_task_lock, flags);
597 	if (cmd->state_active) {
598 		list_del(&cmd->state_list);
599 		cmd->state_active = false;
600 	}
601 	spin_unlock_irqrestore(&dev->execute_task_lock, flags);
602 }
603 
604 static int transport_cmd_check_stop_to_fabric(struct se_cmd *cmd)
605 {
606 	unsigned long flags;
607 
608 	target_remove_from_state_list(cmd);
609 
610 	/*
611 	 * Clear struct se_cmd->se_lun before the handoff to FE.
612 	 */
613 	cmd->se_lun = NULL;
614 
615 	spin_lock_irqsave(&cmd->t_state_lock, flags);
616 	/*
617 	 * Determine if frontend context caller is requesting the stopping of
618 	 * this command for frontend exceptions.
619 	 */
620 	if (cmd->transport_state & CMD_T_STOP) {
621 		pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08llx\n",
622 			__func__, __LINE__, cmd->tag);
623 
624 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
625 
626 		complete_all(&cmd->t_transport_stop_comp);
627 		return 1;
628 	}
629 	cmd->transport_state &= ~CMD_T_ACTIVE;
630 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
631 
632 	/*
633 	 * Some fabric modules like tcm_loop can release their internally
634 	 * allocated I/O reference and struct se_cmd now.
635 	 *
636 	 * Fabric modules are expected to return '1' here if the se_cmd being
637 	 * passed is released at this point, or zero if not being released.
638 	 */
639 	return cmd->se_tfo->check_stop_free(cmd);
640 }
641 
642 static void transport_lun_remove_cmd(struct se_cmd *cmd)
643 {
644 	struct se_lun *lun = cmd->se_lun;
645 
646 	if (!lun)
647 		return;
648 
649 	if (cmpxchg(&cmd->lun_ref_active, true, false))
650 		percpu_ref_put(&lun->lun_ref);
651 }
652 
653 int transport_cmd_finish_abort(struct se_cmd *cmd, int remove)
654 {
655 	bool ack_kref = (cmd->se_cmd_flags & SCF_ACK_KREF);
656 	int ret = 0;
657 
658 	if (cmd->se_cmd_flags & SCF_SE_LUN_CMD)
659 		transport_lun_remove_cmd(cmd);
660 	/*
661 	 * Allow the fabric driver to unmap any resources before
662 	 * releasing the descriptor via TFO->release_cmd()
663 	 */
664 	if (remove)
665 		cmd->se_tfo->aborted_task(cmd);
666 
667 	if (transport_cmd_check_stop_to_fabric(cmd))
668 		return 1;
669 	if (remove && ack_kref)
670 		ret = target_put_sess_cmd(cmd);
671 
672 	return ret;
673 }
674 
675 static void target_complete_failure_work(struct work_struct *work)
676 {
677 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
678 
679 	transport_generic_request_failure(cmd,
680 			TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE);
681 }
682 
683 /*
684  * Used when asking transport to copy Sense Data from the underlying
685  * Linux/SCSI struct scsi_cmnd
686  */
687 static unsigned char *transport_get_sense_buffer(struct se_cmd *cmd)
688 {
689 	struct se_device *dev = cmd->se_dev;
690 
691 	WARN_ON(!cmd->se_lun);
692 
693 	if (!dev)
694 		return NULL;
695 
696 	if (cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION)
697 		return NULL;
698 
699 	cmd->scsi_sense_length = TRANSPORT_SENSE_BUFFER;
700 
701 	pr_debug("HBA_[%u]_PLUG[%s]: Requesting sense for SAM STATUS: 0x%02x\n",
702 		dev->se_hba->hba_id, dev->transport->name, cmd->scsi_status);
703 	return cmd->sense_buffer;
704 }
705 
706 void transport_copy_sense_to_cmd(struct se_cmd *cmd, unsigned char *sense)
707 {
708 	unsigned char *cmd_sense_buf;
709 	unsigned long flags;
710 
711 	spin_lock_irqsave(&cmd->t_state_lock, flags);
712 	cmd_sense_buf = transport_get_sense_buffer(cmd);
713 	if (!cmd_sense_buf) {
714 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
715 		return;
716 	}
717 
718 	cmd->se_cmd_flags |= SCF_TRANSPORT_TASK_SENSE;
719 	memcpy(cmd_sense_buf, sense, cmd->scsi_sense_length);
720 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
721 }
722 EXPORT_SYMBOL(transport_copy_sense_to_cmd);
723 
724 void target_complete_cmd(struct se_cmd *cmd, u8 scsi_status)
725 {
726 	struct se_device *dev = cmd->se_dev;
727 	int success;
728 	unsigned long flags;
729 
730 	cmd->scsi_status = scsi_status;
731 
732 	spin_lock_irqsave(&cmd->t_state_lock, flags);
733 	switch (cmd->scsi_status) {
734 	case SAM_STAT_CHECK_CONDITION:
735 		if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE)
736 			success = 1;
737 		else
738 			success = 0;
739 		break;
740 	default:
741 		success = 1;
742 		break;
743 	}
744 
745 	/*
746 	 * Check for case where an explicit ABORT_TASK has been received
747 	 * and transport_wait_for_tasks() will be waiting for completion..
748 	 */
749 	if (cmd->transport_state & CMD_T_ABORTED ||
750 	    cmd->transport_state & CMD_T_STOP) {
751 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
752 		/*
753 		 * If COMPARE_AND_WRITE was stopped by __transport_wait_for_tasks(),
754 		 * release se_device->caw_sem obtained by sbc_compare_and_write()
755 		 * since target_complete_ok_work() or target_complete_failure_work()
756 		 * won't be called to invoke the normal CAW completion callbacks.
757 		 */
758 		if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) {
759 			up(&dev->caw_sem);
760 		}
761 		complete_all(&cmd->t_transport_stop_comp);
762 		return;
763 	} else if (!success) {
764 		INIT_WORK(&cmd->work, target_complete_failure_work);
765 	} else {
766 		INIT_WORK(&cmd->work, target_complete_ok_work);
767 	}
768 
769 	cmd->t_state = TRANSPORT_COMPLETE;
770 	cmd->transport_state |= (CMD_T_COMPLETE | CMD_T_ACTIVE);
771 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
772 
773 	if (cmd->se_cmd_flags & SCF_USE_CPUID)
774 		queue_work_on(cmd->cpuid, target_completion_wq, &cmd->work);
775 	else
776 		queue_work(target_completion_wq, &cmd->work);
777 }
778 EXPORT_SYMBOL(target_complete_cmd);
779 
780 void target_complete_cmd_with_length(struct se_cmd *cmd, u8 scsi_status, int length)
781 {
782 	if (scsi_status == SAM_STAT_GOOD && length < cmd->data_length) {
783 		if (cmd->se_cmd_flags & SCF_UNDERFLOW_BIT) {
784 			cmd->residual_count += cmd->data_length - length;
785 		} else {
786 			cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
787 			cmd->residual_count = cmd->data_length - length;
788 		}
789 
790 		cmd->data_length = length;
791 	}
792 
793 	target_complete_cmd(cmd, scsi_status);
794 }
795 EXPORT_SYMBOL(target_complete_cmd_with_length);
796 
797 static void target_add_to_state_list(struct se_cmd *cmd)
798 {
799 	struct se_device *dev = cmd->se_dev;
800 	unsigned long flags;
801 
802 	spin_lock_irqsave(&dev->execute_task_lock, flags);
803 	if (!cmd->state_active) {
804 		list_add_tail(&cmd->state_list, &dev->state_list);
805 		cmd->state_active = true;
806 	}
807 	spin_unlock_irqrestore(&dev->execute_task_lock, flags);
808 }
809 
810 /*
811  * Handle QUEUE_FULL / -EAGAIN and -ENOMEM status
812  */
813 static void transport_write_pending_qf(struct se_cmd *cmd);
814 static void transport_complete_qf(struct se_cmd *cmd);
815 
816 void target_qf_do_work(struct work_struct *work)
817 {
818 	struct se_device *dev = container_of(work, struct se_device,
819 					qf_work_queue);
820 	LIST_HEAD(qf_cmd_list);
821 	struct se_cmd *cmd, *cmd_tmp;
822 
823 	spin_lock_irq(&dev->qf_cmd_lock);
824 	list_splice_init(&dev->qf_cmd_list, &qf_cmd_list);
825 	spin_unlock_irq(&dev->qf_cmd_lock);
826 
827 	list_for_each_entry_safe(cmd, cmd_tmp, &qf_cmd_list, se_qf_node) {
828 		list_del(&cmd->se_qf_node);
829 		atomic_dec_mb(&dev->dev_qf_count);
830 
831 		pr_debug("Processing %s cmd: %p QUEUE_FULL in work queue"
832 			" context: %s\n", cmd->se_tfo->get_fabric_name(), cmd,
833 			(cmd->t_state == TRANSPORT_COMPLETE_QF_OK) ? "COMPLETE_OK" :
834 			(cmd->t_state == TRANSPORT_COMPLETE_QF_WP) ? "WRITE_PENDING"
835 			: "UNKNOWN");
836 
837 		if (cmd->t_state == TRANSPORT_COMPLETE_QF_WP)
838 			transport_write_pending_qf(cmd);
839 		else if (cmd->t_state == TRANSPORT_COMPLETE_QF_OK ||
840 			 cmd->t_state == TRANSPORT_COMPLETE_QF_ERR)
841 			transport_complete_qf(cmd);
842 	}
843 }
844 
845 unsigned char *transport_dump_cmd_direction(struct se_cmd *cmd)
846 {
847 	switch (cmd->data_direction) {
848 	case DMA_NONE:
849 		return "NONE";
850 	case DMA_FROM_DEVICE:
851 		return "READ";
852 	case DMA_TO_DEVICE:
853 		return "WRITE";
854 	case DMA_BIDIRECTIONAL:
855 		return "BIDI";
856 	default:
857 		break;
858 	}
859 
860 	return "UNKNOWN";
861 }
862 
863 void transport_dump_dev_state(
864 	struct se_device *dev,
865 	char *b,
866 	int *bl)
867 {
868 	*bl += sprintf(b + *bl, "Status: ");
869 	if (dev->export_count)
870 		*bl += sprintf(b + *bl, "ACTIVATED");
871 	else
872 		*bl += sprintf(b + *bl, "DEACTIVATED");
873 
874 	*bl += sprintf(b + *bl, "  Max Queue Depth: %d", dev->queue_depth);
875 	*bl += sprintf(b + *bl, "  SectorSize: %u  HwMaxSectors: %u\n",
876 		dev->dev_attrib.block_size,
877 		dev->dev_attrib.hw_max_sectors);
878 	*bl += sprintf(b + *bl, "        ");
879 }
880 
881 void transport_dump_vpd_proto_id(
882 	struct t10_vpd *vpd,
883 	unsigned char *p_buf,
884 	int p_buf_len)
885 {
886 	unsigned char buf[VPD_TMP_BUF_SIZE];
887 	int len;
888 
889 	memset(buf, 0, VPD_TMP_BUF_SIZE);
890 	len = sprintf(buf, "T10 VPD Protocol Identifier: ");
891 
892 	switch (vpd->protocol_identifier) {
893 	case 0x00:
894 		sprintf(buf+len, "Fibre Channel\n");
895 		break;
896 	case 0x10:
897 		sprintf(buf+len, "Parallel SCSI\n");
898 		break;
899 	case 0x20:
900 		sprintf(buf+len, "SSA\n");
901 		break;
902 	case 0x30:
903 		sprintf(buf+len, "IEEE 1394\n");
904 		break;
905 	case 0x40:
906 		sprintf(buf+len, "SCSI Remote Direct Memory Access"
907 				" Protocol\n");
908 		break;
909 	case 0x50:
910 		sprintf(buf+len, "Internet SCSI (iSCSI)\n");
911 		break;
912 	case 0x60:
913 		sprintf(buf+len, "SAS Serial SCSI Protocol\n");
914 		break;
915 	case 0x70:
916 		sprintf(buf+len, "Automation/Drive Interface Transport"
917 				" Protocol\n");
918 		break;
919 	case 0x80:
920 		sprintf(buf+len, "AT Attachment Interface ATA/ATAPI\n");
921 		break;
922 	default:
923 		sprintf(buf+len, "Unknown 0x%02x\n",
924 				vpd->protocol_identifier);
925 		break;
926 	}
927 
928 	if (p_buf)
929 		strncpy(p_buf, buf, p_buf_len);
930 	else
931 		pr_debug("%s", buf);
932 }
933 
934 void
935 transport_set_vpd_proto_id(struct t10_vpd *vpd, unsigned char *page_83)
936 {
937 	/*
938 	 * Check if the Protocol Identifier Valid (PIV) bit is set..
939 	 *
940 	 * from spc3r23.pdf section 7.5.1
941 	 */
942 	 if (page_83[1] & 0x80) {
943 		vpd->protocol_identifier = (page_83[0] & 0xf0);
944 		vpd->protocol_identifier_set = 1;
945 		transport_dump_vpd_proto_id(vpd, NULL, 0);
946 	}
947 }
948 EXPORT_SYMBOL(transport_set_vpd_proto_id);
949 
950 int transport_dump_vpd_assoc(
951 	struct t10_vpd *vpd,
952 	unsigned char *p_buf,
953 	int p_buf_len)
954 {
955 	unsigned char buf[VPD_TMP_BUF_SIZE];
956 	int ret = 0;
957 	int len;
958 
959 	memset(buf, 0, VPD_TMP_BUF_SIZE);
960 	len = sprintf(buf, "T10 VPD Identifier Association: ");
961 
962 	switch (vpd->association) {
963 	case 0x00:
964 		sprintf(buf+len, "addressed logical unit\n");
965 		break;
966 	case 0x10:
967 		sprintf(buf+len, "target port\n");
968 		break;
969 	case 0x20:
970 		sprintf(buf+len, "SCSI target device\n");
971 		break;
972 	default:
973 		sprintf(buf+len, "Unknown 0x%02x\n", vpd->association);
974 		ret = -EINVAL;
975 		break;
976 	}
977 
978 	if (p_buf)
979 		strncpy(p_buf, buf, p_buf_len);
980 	else
981 		pr_debug("%s", buf);
982 
983 	return ret;
984 }
985 
986 int transport_set_vpd_assoc(struct t10_vpd *vpd, unsigned char *page_83)
987 {
988 	/*
989 	 * The VPD identification association..
990 	 *
991 	 * from spc3r23.pdf Section 7.6.3.1 Table 297
992 	 */
993 	vpd->association = (page_83[1] & 0x30);
994 	return transport_dump_vpd_assoc(vpd, NULL, 0);
995 }
996 EXPORT_SYMBOL(transport_set_vpd_assoc);
997 
998 int transport_dump_vpd_ident_type(
999 	struct t10_vpd *vpd,
1000 	unsigned char *p_buf,
1001 	int p_buf_len)
1002 {
1003 	unsigned char buf[VPD_TMP_BUF_SIZE];
1004 	int ret = 0;
1005 	int len;
1006 
1007 	memset(buf, 0, VPD_TMP_BUF_SIZE);
1008 	len = sprintf(buf, "T10 VPD Identifier Type: ");
1009 
1010 	switch (vpd->device_identifier_type) {
1011 	case 0x00:
1012 		sprintf(buf+len, "Vendor specific\n");
1013 		break;
1014 	case 0x01:
1015 		sprintf(buf+len, "T10 Vendor ID based\n");
1016 		break;
1017 	case 0x02:
1018 		sprintf(buf+len, "EUI-64 based\n");
1019 		break;
1020 	case 0x03:
1021 		sprintf(buf+len, "NAA\n");
1022 		break;
1023 	case 0x04:
1024 		sprintf(buf+len, "Relative target port identifier\n");
1025 		break;
1026 	case 0x08:
1027 		sprintf(buf+len, "SCSI name string\n");
1028 		break;
1029 	default:
1030 		sprintf(buf+len, "Unsupported: 0x%02x\n",
1031 				vpd->device_identifier_type);
1032 		ret = -EINVAL;
1033 		break;
1034 	}
1035 
1036 	if (p_buf) {
1037 		if (p_buf_len < strlen(buf)+1)
1038 			return -EINVAL;
1039 		strncpy(p_buf, buf, p_buf_len);
1040 	} else {
1041 		pr_debug("%s", buf);
1042 	}
1043 
1044 	return ret;
1045 }
1046 
1047 int transport_set_vpd_ident_type(struct t10_vpd *vpd, unsigned char *page_83)
1048 {
1049 	/*
1050 	 * The VPD identifier type..
1051 	 *
1052 	 * from spc3r23.pdf Section 7.6.3.1 Table 298
1053 	 */
1054 	vpd->device_identifier_type = (page_83[1] & 0x0f);
1055 	return transport_dump_vpd_ident_type(vpd, NULL, 0);
1056 }
1057 EXPORT_SYMBOL(transport_set_vpd_ident_type);
1058 
1059 int transport_dump_vpd_ident(
1060 	struct t10_vpd *vpd,
1061 	unsigned char *p_buf,
1062 	int p_buf_len)
1063 {
1064 	unsigned char buf[VPD_TMP_BUF_SIZE];
1065 	int ret = 0;
1066 
1067 	memset(buf, 0, VPD_TMP_BUF_SIZE);
1068 
1069 	switch (vpd->device_identifier_code_set) {
1070 	case 0x01: /* Binary */
1071 		snprintf(buf, sizeof(buf),
1072 			"T10 VPD Binary Device Identifier: %s\n",
1073 			&vpd->device_identifier[0]);
1074 		break;
1075 	case 0x02: /* ASCII */
1076 		snprintf(buf, sizeof(buf),
1077 			"T10 VPD ASCII Device Identifier: %s\n",
1078 			&vpd->device_identifier[0]);
1079 		break;
1080 	case 0x03: /* UTF-8 */
1081 		snprintf(buf, sizeof(buf),
1082 			"T10 VPD UTF-8 Device Identifier: %s\n",
1083 			&vpd->device_identifier[0]);
1084 		break;
1085 	default:
1086 		sprintf(buf, "T10 VPD Device Identifier encoding unsupported:"
1087 			" 0x%02x", vpd->device_identifier_code_set);
1088 		ret = -EINVAL;
1089 		break;
1090 	}
1091 
1092 	if (p_buf)
1093 		strncpy(p_buf, buf, p_buf_len);
1094 	else
1095 		pr_debug("%s", buf);
1096 
1097 	return ret;
1098 }
1099 
1100 int
1101 transport_set_vpd_ident(struct t10_vpd *vpd, unsigned char *page_83)
1102 {
1103 	static const char hex_str[] = "0123456789abcdef";
1104 	int j = 0, i = 4; /* offset to start of the identifier */
1105 
1106 	/*
1107 	 * The VPD Code Set (encoding)
1108 	 *
1109 	 * from spc3r23.pdf Section 7.6.3.1 Table 296
1110 	 */
1111 	vpd->device_identifier_code_set = (page_83[0] & 0x0f);
1112 	switch (vpd->device_identifier_code_set) {
1113 	case 0x01: /* Binary */
1114 		vpd->device_identifier[j++] =
1115 				hex_str[vpd->device_identifier_type];
1116 		while (i < (4 + page_83[3])) {
1117 			vpd->device_identifier[j++] =
1118 				hex_str[(page_83[i] & 0xf0) >> 4];
1119 			vpd->device_identifier[j++] =
1120 				hex_str[page_83[i] & 0x0f];
1121 			i++;
1122 		}
1123 		break;
1124 	case 0x02: /* ASCII */
1125 	case 0x03: /* UTF-8 */
1126 		while (i < (4 + page_83[3]))
1127 			vpd->device_identifier[j++] = page_83[i++];
1128 		break;
1129 	default:
1130 		break;
1131 	}
1132 
1133 	return transport_dump_vpd_ident(vpd, NULL, 0);
1134 }
1135 EXPORT_SYMBOL(transport_set_vpd_ident);
1136 
1137 static sense_reason_t
1138 target_check_max_data_sg_nents(struct se_cmd *cmd, struct se_device *dev,
1139 			       unsigned int size)
1140 {
1141 	u32 mtl;
1142 
1143 	if (!cmd->se_tfo->max_data_sg_nents)
1144 		return TCM_NO_SENSE;
1145 	/*
1146 	 * Check if fabric enforced maximum SGL entries per I/O descriptor
1147 	 * exceeds se_cmd->data_length.  If true, set SCF_UNDERFLOW_BIT +
1148 	 * residual_count and reduce original cmd->data_length to maximum
1149 	 * length based on single PAGE_SIZE entry scatter-lists.
1150 	 */
1151 	mtl = (cmd->se_tfo->max_data_sg_nents * PAGE_SIZE);
1152 	if (cmd->data_length > mtl) {
1153 		/*
1154 		 * If an existing CDB overflow is present, calculate new residual
1155 		 * based on CDB size minus fabric maximum transfer length.
1156 		 *
1157 		 * If an existing CDB underflow is present, calculate new residual
1158 		 * based on original cmd->data_length minus fabric maximum transfer
1159 		 * length.
1160 		 *
1161 		 * Otherwise, set the underflow residual based on cmd->data_length
1162 		 * minus fabric maximum transfer length.
1163 		 */
1164 		if (cmd->se_cmd_flags & SCF_OVERFLOW_BIT) {
1165 			cmd->residual_count = (size - mtl);
1166 		} else if (cmd->se_cmd_flags & SCF_UNDERFLOW_BIT) {
1167 			u32 orig_dl = size + cmd->residual_count;
1168 			cmd->residual_count = (orig_dl - mtl);
1169 		} else {
1170 			cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
1171 			cmd->residual_count = (cmd->data_length - mtl);
1172 		}
1173 		cmd->data_length = mtl;
1174 		/*
1175 		 * Reset sbc_check_prot() calculated protection payload
1176 		 * length based upon the new smaller MTL.
1177 		 */
1178 		if (cmd->prot_length) {
1179 			u32 sectors = (mtl / dev->dev_attrib.block_size);
1180 			cmd->prot_length = dev->prot_length * sectors;
1181 		}
1182 	}
1183 	return TCM_NO_SENSE;
1184 }
1185 
1186 sense_reason_t
1187 target_cmd_size_check(struct se_cmd *cmd, unsigned int size)
1188 {
1189 	struct se_device *dev = cmd->se_dev;
1190 
1191 	if (cmd->unknown_data_length) {
1192 		cmd->data_length = size;
1193 	} else if (size != cmd->data_length) {
1194 		pr_warn_ratelimited("TARGET_CORE[%s]: Expected Transfer Length:"
1195 			" %u does not match SCSI CDB Length: %u for SAM Opcode:"
1196 			" 0x%02x\n", cmd->se_tfo->get_fabric_name(),
1197 				cmd->data_length, size, cmd->t_task_cdb[0]);
1198 
1199 		if (cmd->data_direction == DMA_TO_DEVICE) {
1200 			if (cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) {
1201 				pr_err_ratelimited("Rejecting underflow/overflow"
1202 						   " for WRITE data CDB\n");
1203 				return TCM_INVALID_CDB_FIELD;
1204 			}
1205 			/*
1206 			 * Some fabric drivers like iscsi-target still expect to
1207 			 * always reject overflow writes.  Reject this case until
1208 			 * full fabric driver level support for overflow writes
1209 			 * is introduced tree-wide.
1210 			 */
1211 			if (size > cmd->data_length) {
1212 				pr_err_ratelimited("Rejecting overflow for"
1213 						   " WRITE control CDB\n");
1214 				return TCM_INVALID_CDB_FIELD;
1215 			}
1216 		}
1217 		/*
1218 		 * Reject READ_* or WRITE_* with overflow/underflow for
1219 		 * type SCF_SCSI_DATA_CDB.
1220 		 */
1221 		if (dev->dev_attrib.block_size != 512)  {
1222 			pr_err("Failing OVERFLOW/UNDERFLOW for LBA op"
1223 				" CDB on non 512-byte sector setup subsystem"
1224 				" plugin: %s\n", dev->transport->name);
1225 			/* Returns CHECK_CONDITION + INVALID_CDB_FIELD */
1226 			return TCM_INVALID_CDB_FIELD;
1227 		}
1228 		/*
1229 		 * For the overflow case keep the existing fabric provided
1230 		 * ->data_length.  Otherwise for the underflow case, reset
1231 		 * ->data_length to the smaller SCSI expected data transfer
1232 		 * length.
1233 		 */
1234 		if (size > cmd->data_length) {
1235 			cmd->se_cmd_flags |= SCF_OVERFLOW_BIT;
1236 			cmd->residual_count = (size - cmd->data_length);
1237 		} else {
1238 			cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
1239 			cmd->residual_count = (cmd->data_length - size);
1240 			cmd->data_length = size;
1241 		}
1242 	}
1243 
1244 	return target_check_max_data_sg_nents(cmd, dev, size);
1245 
1246 }
1247 
1248 /*
1249  * Used by fabric modules containing a local struct se_cmd within their
1250  * fabric dependent per I/O descriptor.
1251  *
1252  * Preserves the value of @cmd->tag.
1253  */
1254 void transport_init_se_cmd(
1255 	struct se_cmd *cmd,
1256 	const struct target_core_fabric_ops *tfo,
1257 	struct se_session *se_sess,
1258 	u32 data_length,
1259 	int data_direction,
1260 	int task_attr,
1261 	unsigned char *sense_buffer)
1262 {
1263 	INIT_LIST_HEAD(&cmd->se_delayed_node);
1264 	INIT_LIST_HEAD(&cmd->se_qf_node);
1265 	INIT_LIST_HEAD(&cmd->se_cmd_list);
1266 	INIT_LIST_HEAD(&cmd->state_list);
1267 	init_completion(&cmd->t_transport_stop_comp);
1268 	init_completion(&cmd->cmd_wait_comp);
1269 	spin_lock_init(&cmd->t_state_lock);
1270 	INIT_WORK(&cmd->work, NULL);
1271 	kref_init(&cmd->cmd_kref);
1272 
1273 	cmd->se_tfo = tfo;
1274 	cmd->se_sess = se_sess;
1275 	cmd->data_length = data_length;
1276 	cmd->data_direction = data_direction;
1277 	cmd->sam_task_attr = task_attr;
1278 	cmd->sense_buffer = sense_buffer;
1279 
1280 	cmd->state_active = false;
1281 }
1282 EXPORT_SYMBOL(transport_init_se_cmd);
1283 
1284 static sense_reason_t
1285 transport_check_alloc_task_attr(struct se_cmd *cmd)
1286 {
1287 	struct se_device *dev = cmd->se_dev;
1288 
1289 	/*
1290 	 * Check if SAM Task Attribute emulation is enabled for this
1291 	 * struct se_device storage object
1292 	 */
1293 	if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
1294 		return 0;
1295 
1296 	if (cmd->sam_task_attr == TCM_ACA_TAG) {
1297 		pr_debug("SAM Task Attribute ACA"
1298 			" emulation is not supported\n");
1299 		return TCM_INVALID_CDB_FIELD;
1300 	}
1301 
1302 	return 0;
1303 }
1304 
1305 sense_reason_t
1306 target_setup_cmd_from_cdb(struct se_cmd *cmd, unsigned char *cdb)
1307 {
1308 	struct se_device *dev = cmd->se_dev;
1309 	sense_reason_t ret;
1310 
1311 	/*
1312 	 * Ensure that the received CDB is less than the max (252 + 8) bytes
1313 	 * for VARIABLE_LENGTH_CMD
1314 	 */
1315 	if (scsi_command_size(cdb) > SCSI_MAX_VARLEN_CDB_SIZE) {
1316 		pr_err("Received SCSI CDB with command_size: %d that"
1317 			" exceeds SCSI_MAX_VARLEN_CDB_SIZE: %d\n",
1318 			scsi_command_size(cdb), SCSI_MAX_VARLEN_CDB_SIZE);
1319 		return TCM_INVALID_CDB_FIELD;
1320 	}
1321 	/*
1322 	 * If the received CDB is larger than TCM_MAX_COMMAND_SIZE,
1323 	 * allocate the additional extended CDB buffer now..  Otherwise
1324 	 * setup the pointer from __t_task_cdb to t_task_cdb.
1325 	 */
1326 	if (scsi_command_size(cdb) > sizeof(cmd->__t_task_cdb)) {
1327 		cmd->t_task_cdb = kzalloc(scsi_command_size(cdb),
1328 						GFP_KERNEL);
1329 		if (!cmd->t_task_cdb) {
1330 			pr_err("Unable to allocate cmd->t_task_cdb"
1331 				" %u > sizeof(cmd->__t_task_cdb): %lu ops\n",
1332 				scsi_command_size(cdb),
1333 				(unsigned long)sizeof(cmd->__t_task_cdb));
1334 			return TCM_OUT_OF_RESOURCES;
1335 		}
1336 	} else
1337 		cmd->t_task_cdb = &cmd->__t_task_cdb[0];
1338 	/*
1339 	 * Copy the original CDB into cmd->
1340 	 */
1341 	memcpy(cmd->t_task_cdb, cdb, scsi_command_size(cdb));
1342 
1343 	trace_target_sequencer_start(cmd);
1344 
1345 	ret = dev->transport->parse_cdb(cmd);
1346 	if (ret == TCM_UNSUPPORTED_SCSI_OPCODE)
1347 		pr_warn_ratelimited("%s/%s: Unsupported SCSI Opcode 0x%02x, sending CHECK_CONDITION.\n",
1348 				    cmd->se_tfo->get_fabric_name(),
1349 				    cmd->se_sess->se_node_acl->initiatorname,
1350 				    cmd->t_task_cdb[0]);
1351 	if (ret)
1352 		return ret;
1353 
1354 	ret = transport_check_alloc_task_attr(cmd);
1355 	if (ret)
1356 		return ret;
1357 
1358 	cmd->se_cmd_flags |= SCF_SUPPORTED_SAM_OPCODE;
1359 	atomic_long_inc(&cmd->se_lun->lun_stats.cmd_pdus);
1360 	return 0;
1361 }
1362 EXPORT_SYMBOL(target_setup_cmd_from_cdb);
1363 
1364 /*
1365  * Used by fabric module frontends to queue tasks directly.
1366  * May only be used from process context.
1367  */
1368 int transport_handle_cdb_direct(
1369 	struct se_cmd *cmd)
1370 {
1371 	sense_reason_t ret;
1372 
1373 	if (!cmd->se_lun) {
1374 		dump_stack();
1375 		pr_err("cmd->se_lun is NULL\n");
1376 		return -EINVAL;
1377 	}
1378 	if (in_interrupt()) {
1379 		dump_stack();
1380 		pr_err("transport_generic_handle_cdb cannot be called"
1381 				" from interrupt context\n");
1382 		return -EINVAL;
1383 	}
1384 	/*
1385 	 * Set TRANSPORT_NEW_CMD state and CMD_T_ACTIVE to ensure that
1386 	 * outstanding descriptors are handled correctly during shutdown via
1387 	 * transport_wait_for_tasks()
1388 	 *
1389 	 * Also, we don't take cmd->t_state_lock here as we only expect
1390 	 * this to be called for initial descriptor submission.
1391 	 */
1392 	cmd->t_state = TRANSPORT_NEW_CMD;
1393 	cmd->transport_state |= CMD_T_ACTIVE;
1394 
1395 	/*
1396 	 * transport_generic_new_cmd() is already handling QUEUE_FULL,
1397 	 * so follow TRANSPORT_NEW_CMD processing thread context usage
1398 	 * and call transport_generic_request_failure() if necessary..
1399 	 */
1400 	ret = transport_generic_new_cmd(cmd);
1401 	if (ret)
1402 		transport_generic_request_failure(cmd, ret);
1403 	return 0;
1404 }
1405 EXPORT_SYMBOL(transport_handle_cdb_direct);
1406 
1407 sense_reason_t
1408 transport_generic_map_mem_to_cmd(struct se_cmd *cmd, struct scatterlist *sgl,
1409 		u32 sgl_count, struct scatterlist *sgl_bidi, u32 sgl_bidi_count)
1410 {
1411 	if (!sgl || !sgl_count)
1412 		return 0;
1413 
1414 	/*
1415 	 * Reject SCSI data overflow with map_mem_to_cmd() as incoming
1416 	 * scatterlists already have been set to follow what the fabric
1417 	 * passes for the original expected data transfer length.
1418 	 */
1419 	if (cmd->se_cmd_flags & SCF_OVERFLOW_BIT) {
1420 		pr_warn("Rejecting SCSI DATA overflow for fabric using"
1421 			" SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC\n");
1422 		return TCM_INVALID_CDB_FIELD;
1423 	}
1424 
1425 	cmd->t_data_sg = sgl;
1426 	cmd->t_data_nents = sgl_count;
1427 	cmd->t_bidi_data_sg = sgl_bidi;
1428 	cmd->t_bidi_data_nents = sgl_bidi_count;
1429 
1430 	cmd->se_cmd_flags |= SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC;
1431 	return 0;
1432 }
1433 
1434 /*
1435  * target_submit_cmd_map_sgls - lookup unpacked lun and submit uninitialized
1436  * 			 se_cmd + use pre-allocated SGL memory.
1437  *
1438  * @se_cmd: command descriptor to submit
1439  * @se_sess: associated se_sess for endpoint
1440  * @cdb: pointer to SCSI CDB
1441  * @sense: pointer to SCSI sense buffer
1442  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1443  * @data_length: fabric expected data transfer length
1444  * @task_addr: SAM task attribute
1445  * @data_dir: DMA data direction
1446  * @flags: flags for command submission from target_sc_flags_tables
1447  * @sgl: struct scatterlist memory for unidirectional mapping
1448  * @sgl_count: scatterlist count for unidirectional mapping
1449  * @sgl_bidi: struct scatterlist memory for bidirectional READ mapping
1450  * @sgl_bidi_count: scatterlist count for bidirectional READ mapping
1451  * @sgl_prot: struct scatterlist memory protection information
1452  * @sgl_prot_count: scatterlist count for protection information
1453  *
1454  * Task tags are supported if the caller has set @se_cmd->tag.
1455  *
1456  * Returns non zero to signal active I/O shutdown failure.  All other
1457  * setup exceptions will be returned as a SCSI CHECK_CONDITION response,
1458  * but still return zero here.
1459  *
1460  * This may only be called from process context, and also currently
1461  * assumes internal allocation of fabric payload buffer by target-core.
1462  */
1463 int target_submit_cmd_map_sgls(struct se_cmd *se_cmd, struct se_session *se_sess,
1464 		unsigned char *cdb, unsigned char *sense, u64 unpacked_lun,
1465 		u32 data_length, int task_attr, int data_dir, int flags,
1466 		struct scatterlist *sgl, u32 sgl_count,
1467 		struct scatterlist *sgl_bidi, u32 sgl_bidi_count,
1468 		struct scatterlist *sgl_prot, u32 sgl_prot_count)
1469 {
1470 	struct se_portal_group *se_tpg;
1471 	sense_reason_t rc;
1472 	int ret;
1473 
1474 	se_tpg = se_sess->se_tpg;
1475 	BUG_ON(!se_tpg);
1476 	BUG_ON(se_cmd->se_tfo || se_cmd->se_sess);
1477 	BUG_ON(in_interrupt());
1478 	/*
1479 	 * Initialize se_cmd for target operation.  From this point
1480 	 * exceptions are handled by sending exception status via
1481 	 * target_core_fabric_ops->queue_status() callback
1482 	 */
1483 	transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess,
1484 				data_length, data_dir, task_attr, sense);
1485 
1486 	if (flags & TARGET_SCF_USE_CPUID)
1487 		se_cmd->se_cmd_flags |= SCF_USE_CPUID;
1488 	else
1489 		se_cmd->cpuid = WORK_CPU_UNBOUND;
1490 
1491 	if (flags & TARGET_SCF_UNKNOWN_SIZE)
1492 		se_cmd->unknown_data_length = 1;
1493 	/*
1494 	 * Obtain struct se_cmd->cmd_kref reference and add new cmd to
1495 	 * se_sess->sess_cmd_list.  A second kref_get here is necessary
1496 	 * for fabrics using TARGET_SCF_ACK_KREF that expect a second
1497 	 * kref_put() to happen during fabric packet acknowledgement.
1498 	 */
1499 	ret = target_get_sess_cmd(se_cmd, flags & TARGET_SCF_ACK_KREF);
1500 	if (ret)
1501 		return ret;
1502 	/*
1503 	 * Signal bidirectional data payloads to target-core
1504 	 */
1505 	if (flags & TARGET_SCF_BIDI_OP)
1506 		se_cmd->se_cmd_flags |= SCF_BIDI;
1507 	/*
1508 	 * Locate se_lun pointer and attach it to struct se_cmd
1509 	 */
1510 	rc = transport_lookup_cmd_lun(se_cmd, unpacked_lun);
1511 	if (rc) {
1512 		transport_send_check_condition_and_sense(se_cmd, rc, 0);
1513 		target_put_sess_cmd(se_cmd);
1514 		return 0;
1515 	}
1516 
1517 	rc = target_setup_cmd_from_cdb(se_cmd, cdb);
1518 	if (rc != 0) {
1519 		transport_generic_request_failure(se_cmd, rc);
1520 		return 0;
1521 	}
1522 
1523 	/*
1524 	 * Save pointers for SGLs containing protection information,
1525 	 * if present.
1526 	 */
1527 	if (sgl_prot_count) {
1528 		se_cmd->t_prot_sg = sgl_prot;
1529 		se_cmd->t_prot_nents = sgl_prot_count;
1530 		se_cmd->se_cmd_flags |= SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC;
1531 	}
1532 
1533 	/*
1534 	 * When a non zero sgl_count has been passed perform SGL passthrough
1535 	 * mapping for pre-allocated fabric memory instead of having target
1536 	 * core perform an internal SGL allocation..
1537 	 */
1538 	if (sgl_count != 0) {
1539 		BUG_ON(!sgl);
1540 
1541 		/*
1542 		 * A work-around for tcm_loop as some userspace code via
1543 		 * scsi-generic do not memset their associated read buffers,
1544 		 * so go ahead and do that here for type non-data CDBs.  Also
1545 		 * note that this is currently guaranteed to be a single SGL
1546 		 * for this case by target core in target_setup_cmd_from_cdb()
1547 		 * -> transport_generic_cmd_sequencer().
1548 		 */
1549 		if (!(se_cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) &&
1550 		     se_cmd->data_direction == DMA_FROM_DEVICE) {
1551 			unsigned char *buf = NULL;
1552 
1553 			if (sgl)
1554 				buf = kmap(sg_page(sgl)) + sgl->offset;
1555 
1556 			if (buf) {
1557 				memset(buf, 0, sgl->length);
1558 				kunmap(sg_page(sgl));
1559 			}
1560 		}
1561 
1562 		rc = transport_generic_map_mem_to_cmd(se_cmd, sgl, sgl_count,
1563 				sgl_bidi, sgl_bidi_count);
1564 		if (rc != 0) {
1565 			transport_generic_request_failure(se_cmd, rc);
1566 			return 0;
1567 		}
1568 	}
1569 
1570 	/*
1571 	 * Check if we need to delay processing because of ALUA
1572 	 * Active/NonOptimized primary access state..
1573 	 */
1574 	core_alua_check_nonop_delay(se_cmd);
1575 
1576 	transport_handle_cdb_direct(se_cmd);
1577 	return 0;
1578 }
1579 EXPORT_SYMBOL(target_submit_cmd_map_sgls);
1580 
1581 /*
1582  * target_submit_cmd - lookup unpacked lun and submit uninitialized se_cmd
1583  *
1584  * @se_cmd: command descriptor to submit
1585  * @se_sess: associated se_sess for endpoint
1586  * @cdb: pointer to SCSI CDB
1587  * @sense: pointer to SCSI sense buffer
1588  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1589  * @data_length: fabric expected data transfer length
1590  * @task_addr: SAM task attribute
1591  * @data_dir: DMA data direction
1592  * @flags: flags for command submission from target_sc_flags_tables
1593  *
1594  * Task tags are supported if the caller has set @se_cmd->tag.
1595  *
1596  * Returns non zero to signal active I/O shutdown failure.  All other
1597  * setup exceptions will be returned as a SCSI CHECK_CONDITION response,
1598  * but still return zero here.
1599  *
1600  * This may only be called from process context, and also currently
1601  * assumes internal allocation of fabric payload buffer by target-core.
1602  *
1603  * It also assumes interal target core SGL memory allocation.
1604  */
1605 int target_submit_cmd(struct se_cmd *se_cmd, struct se_session *se_sess,
1606 		unsigned char *cdb, unsigned char *sense, u64 unpacked_lun,
1607 		u32 data_length, int task_attr, int data_dir, int flags)
1608 {
1609 	return target_submit_cmd_map_sgls(se_cmd, se_sess, cdb, sense,
1610 			unpacked_lun, data_length, task_attr, data_dir,
1611 			flags, NULL, 0, NULL, 0, NULL, 0);
1612 }
1613 EXPORT_SYMBOL(target_submit_cmd);
1614 
1615 static void target_complete_tmr_failure(struct work_struct *work)
1616 {
1617 	struct se_cmd *se_cmd = container_of(work, struct se_cmd, work);
1618 
1619 	se_cmd->se_tmr_req->response = TMR_LUN_DOES_NOT_EXIST;
1620 	se_cmd->se_tfo->queue_tm_rsp(se_cmd);
1621 
1622 	transport_lun_remove_cmd(se_cmd);
1623 	transport_cmd_check_stop_to_fabric(se_cmd);
1624 }
1625 
1626 static bool target_lookup_lun_from_tag(struct se_session *se_sess, u64 tag,
1627 				       u64 *unpacked_lun)
1628 {
1629 	struct se_cmd *se_cmd;
1630 	unsigned long flags;
1631 	bool ret = false;
1632 
1633 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
1634 	list_for_each_entry(se_cmd, &se_sess->sess_cmd_list, se_cmd_list) {
1635 		if (se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
1636 			continue;
1637 
1638 		if (se_cmd->tag == tag) {
1639 			*unpacked_lun = se_cmd->orig_fe_lun;
1640 			ret = true;
1641 			break;
1642 		}
1643 	}
1644 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
1645 
1646 	return ret;
1647 }
1648 
1649 /**
1650  * target_submit_tmr - lookup unpacked lun and submit uninitialized se_cmd
1651  *                     for TMR CDBs
1652  *
1653  * @se_cmd: command descriptor to submit
1654  * @se_sess: associated se_sess for endpoint
1655  * @sense: pointer to SCSI sense buffer
1656  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1657  * @fabric_context: fabric context for TMR req
1658  * @tm_type: Type of TM request
1659  * @gfp: gfp type for caller
1660  * @tag: referenced task tag for TMR_ABORT_TASK
1661  * @flags: submit cmd flags
1662  *
1663  * Callable from all contexts.
1664  **/
1665 
1666 int target_submit_tmr(struct se_cmd *se_cmd, struct se_session *se_sess,
1667 		unsigned char *sense, u64 unpacked_lun,
1668 		void *fabric_tmr_ptr, unsigned char tm_type,
1669 		gfp_t gfp, u64 tag, int flags)
1670 {
1671 	struct se_portal_group *se_tpg;
1672 	int ret;
1673 
1674 	se_tpg = se_sess->se_tpg;
1675 	BUG_ON(!se_tpg);
1676 
1677 	transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess,
1678 			      0, DMA_NONE, TCM_SIMPLE_TAG, sense);
1679 	/*
1680 	 * FIXME: Currently expect caller to handle se_cmd->se_tmr_req
1681 	 * allocation failure.
1682 	 */
1683 	ret = core_tmr_alloc_req(se_cmd, fabric_tmr_ptr, tm_type, gfp);
1684 	if (ret < 0)
1685 		return -ENOMEM;
1686 
1687 	if (tm_type == TMR_ABORT_TASK)
1688 		se_cmd->se_tmr_req->ref_task_tag = tag;
1689 
1690 	/* See target_submit_cmd for commentary */
1691 	ret = target_get_sess_cmd(se_cmd, flags & TARGET_SCF_ACK_KREF);
1692 	if (ret) {
1693 		core_tmr_release_req(se_cmd->se_tmr_req);
1694 		return ret;
1695 	}
1696 	/*
1697 	 * If this is ABORT_TASK with no explicit fabric provided LUN,
1698 	 * go ahead and search active session tags for a match to figure
1699 	 * out unpacked_lun for the original se_cmd.
1700 	 */
1701 	if (tm_type == TMR_ABORT_TASK && (flags & TARGET_SCF_LOOKUP_LUN_FROM_TAG)) {
1702 		if (!target_lookup_lun_from_tag(se_sess, tag, &unpacked_lun))
1703 			goto failure;
1704 	}
1705 
1706 	ret = transport_lookup_tmr_lun(se_cmd, unpacked_lun);
1707 	if (ret)
1708 		goto failure;
1709 
1710 	transport_generic_handle_tmr(se_cmd);
1711 	return 0;
1712 
1713 	/*
1714 	 * For callback during failure handling, push this work off
1715 	 * to process context with TMR_LUN_DOES_NOT_EXIST status.
1716 	 */
1717 failure:
1718 	INIT_WORK(&se_cmd->work, target_complete_tmr_failure);
1719 	schedule_work(&se_cmd->work);
1720 	return 0;
1721 }
1722 EXPORT_SYMBOL(target_submit_tmr);
1723 
1724 /*
1725  * Handle SAM-esque emulation for generic transport request failures.
1726  */
1727 void transport_generic_request_failure(struct se_cmd *cmd,
1728 		sense_reason_t sense_reason)
1729 {
1730 	int ret = 0, post_ret = 0;
1731 
1732 	pr_debug("-----[ Storage Engine Exception; sense_reason %d\n",
1733 		 sense_reason);
1734 	target_show_cmd("-----[ ", cmd);
1735 
1736 	/*
1737 	 * For SAM Task Attribute emulation for failed struct se_cmd
1738 	 */
1739 	transport_complete_task_attr(cmd);
1740 
1741 	/*
1742 	 * Handle special case for COMPARE_AND_WRITE failure, where the
1743 	 * callback is expected to drop the per device ->caw_sem.
1744 	 */
1745 	if ((cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) &&
1746 	     cmd->transport_complete_callback)
1747 		cmd->transport_complete_callback(cmd, false, &post_ret);
1748 
1749 	if (transport_check_aborted_status(cmd, 1))
1750 		return;
1751 
1752 	switch (sense_reason) {
1753 	case TCM_NON_EXISTENT_LUN:
1754 	case TCM_UNSUPPORTED_SCSI_OPCODE:
1755 	case TCM_INVALID_CDB_FIELD:
1756 	case TCM_INVALID_PARAMETER_LIST:
1757 	case TCM_PARAMETER_LIST_LENGTH_ERROR:
1758 	case TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE:
1759 	case TCM_UNKNOWN_MODE_PAGE:
1760 	case TCM_WRITE_PROTECTED:
1761 	case TCM_ADDRESS_OUT_OF_RANGE:
1762 	case TCM_CHECK_CONDITION_ABORT_CMD:
1763 	case TCM_CHECK_CONDITION_UNIT_ATTENTION:
1764 	case TCM_CHECK_CONDITION_NOT_READY:
1765 	case TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED:
1766 	case TCM_LOGICAL_BLOCK_APP_TAG_CHECK_FAILED:
1767 	case TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED:
1768 	case TCM_COPY_TARGET_DEVICE_NOT_REACHABLE:
1769 	case TCM_TOO_MANY_TARGET_DESCS:
1770 	case TCM_UNSUPPORTED_TARGET_DESC_TYPE_CODE:
1771 	case TCM_TOO_MANY_SEGMENT_DESCS:
1772 	case TCM_UNSUPPORTED_SEGMENT_DESC_TYPE_CODE:
1773 		break;
1774 	case TCM_OUT_OF_RESOURCES:
1775 		cmd->scsi_status = SAM_STAT_TASK_SET_FULL;
1776 		goto queue_status;
1777 	case TCM_LUN_BUSY:
1778 		cmd->scsi_status = SAM_STAT_BUSY;
1779 		goto queue_status;
1780 	case TCM_RESERVATION_CONFLICT:
1781 		/*
1782 		 * No SENSE Data payload for this case, set SCSI Status
1783 		 * and queue the response to $FABRIC_MOD.
1784 		 *
1785 		 * Uses linux/include/scsi/scsi.h SAM status codes defs
1786 		 */
1787 		cmd->scsi_status = SAM_STAT_RESERVATION_CONFLICT;
1788 		/*
1789 		 * For UA Interlock Code 11b, a RESERVATION CONFLICT will
1790 		 * establish a UNIT ATTENTION with PREVIOUS RESERVATION
1791 		 * CONFLICT STATUS.
1792 		 *
1793 		 * See spc4r17, section 7.4.6 Control Mode Page, Table 349
1794 		 */
1795 		if (cmd->se_sess &&
1796 		    cmd->se_dev->dev_attrib.emulate_ua_intlck_ctrl == 2) {
1797 			target_ua_allocate_lun(cmd->se_sess->se_node_acl,
1798 					       cmd->orig_fe_lun, 0x2C,
1799 					ASCQ_2CH_PREVIOUS_RESERVATION_CONFLICT_STATUS);
1800 		}
1801 
1802 		goto queue_status;
1803 	default:
1804 		pr_err("Unknown transport error for CDB 0x%02x: %d\n",
1805 			cmd->t_task_cdb[0], sense_reason);
1806 		sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
1807 		break;
1808 	}
1809 
1810 	ret = transport_send_check_condition_and_sense(cmd, sense_reason, 0);
1811 	if (ret)
1812 		goto queue_full;
1813 
1814 check_stop:
1815 	transport_lun_remove_cmd(cmd);
1816 	transport_cmd_check_stop_to_fabric(cmd);
1817 	return;
1818 
1819 queue_status:
1820 	trace_target_cmd_complete(cmd);
1821 	ret = cmd->se_tfo->queue_status(cmd);
1822 	if (!ret)
1823 		goto check_stop;
1824 queue_full:
1825 	transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
1826 }
1827 EXPORT_SYMBOL(transport_generic_request_failure);
1828 
1829 void __target_execute_cmd(struct se_cmd *cmd, bool do_checks)
1830 {
1831 	sense_reason_t ret;
1832 
1833 	if (!cmd->execute_cmd) {
1834 		ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
1835 		goto err;
1836 	}
1837 	if (do_checks) {
1838 		/*
1839 		 * Check for an existing UNIT ATTENTION condition after
1840 		 * target_handle_task_attr() has done SAM task attr
1841 		 * checking, and possibly have already defered execution
1842 		 * out to target_restart_delayed_cmds() context.
1843 		 */
1844 		ret = target_scsi3_ua_check(cmd);
1845 		if (ret)
1846 			goto err;
1847 
1848 		ret = target_alua_state_check(cmd);
1849 		if (ret)
1850 			goto err;
1851 
1852 		ret = target_check_reservation(cmd);
1853 		if (ret) {
1854 			cmd->scsi_status = SAM_STAT_RESERVATION_CONFLICT;
1855 			goto err;
1856 		}
1857 	}
1858 
1859 	ret = cmd->execute_cmd(cmd);
1860 	if (!ret)
1861 		return;
1862 err:
1863 	spin_lock_irq(&cmd->t_state_lock);
1864 	cmd->transport_state &= ~CMD_T_SENT;
1865 	spin_unlock_irq(&cmd->t_state_lock);
1866 
1867 	transport_generic_request_failure(cmd, ret);
1868 }
1869 
1870 static int target_write_prot_action(struct se_cmd *cmd)
1871 {
1872 	u32 sectors;
1873 	/*
1874 	 * Perform WRITE_INSERT of PI using software emulation when backend
1875 	 * device has PI enabled, if the transport has not already generated
1876 	 * PI using hardware WRITE_INSERT offload.
1877 	 */
1878 	switch (cmd->prot_op) {
1879 	case TARGET_PROT_DOUT_INSERT:
1880 		if (!(cmd->se_sess->sup_prot_ops & TARGET_PROT_DOUT_INSERT))
1881 			sbc_dif_generate(cmd);
1882 		break;
1883 	case TARGET_PROT_DOUT_STRIP:
1884 		if (cmd->se_sess->sup_prot_ops & TARGET_PROT_DOUT_STRIP)
1885 			break;
1886 
1887 		sectors = cmd->data_length >> ilog2(cmd->se_dev->dev_attrib.block_size);
1888 		cmd->pi_err = sbc_dif_verify(cmd, cmd->t_task_lba,
1889 					     sectors, 0, cmd->t_prot_sg, 0);
1890 		if (unlikely(cmd->pi_err)) {
1891 			spin_lock_irq(&cmd->t_state_lock);
1892 			cmd->transport_state &= ~CMD_T_SENT;
1893 			spin_unlock_irq(&cmd->t_state_lock);
1894 			transport_generic_request_failure(cmd, cmd->pi_err);
1895 			return -1;
1896 		}
1897 		break;
1898 	default:
1899 		break;
1900 	}
1901 
1902 	return 0;
1903 }
1904 
1905 static bool target_handle_task_attr(struct se_cmd *cmd)
1906 {
1907 	struct se_device *dev = cmd->se_dev;
1908 
1909 	if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
1910 		return false;
1911 
1912 	cmd->se_cmd_flags |= SCF_TASK_ATTR_SET;
1913 
1914 	/*
1915 	 * Check for the existence of HEAD_OF_QUEUE, and if true return 1
1916 	 * to allow the passed struct se_cmd list of tasks to the front of the list.
1917 	 */
1918 	switch (cmd->sam_task_attr) {
1919 	case TCM_HEAD_TAG:
1920 		pr_debug("Added HEAD_OF_QUEUE for CDB: 0x%02x\n",
1921 			 cmd->t_task_cdb[0]);
1922 		return false;
1923 	case TCM_ORDERED_TAG:
1924 		atomic_inc_mb(&dev->dev_ordered_sync);
1925 
1926 		pr_debug("Added ORDERED for CDB: 0x%02x to ordered list\n",
1927 			 cmd->t_task_cdb[0]);
1928 
1929 		/*
1930 		 * Execute an ORDERED command if no other older commands
1931 		 * exist that need to be completed first.
1932 		 */
1933 		if (!atomic_read(&dev->simple_cmds))
1934 			return false;
1935 		break;
1936 	default:
1937 		/*
1938 		 * For SIMPLE and UNTAGGED Task Attribute commands
1939 		 */
1940 		atomic_inc_mb(&dev->simple_cmds);
1941 		break;
1942 	}
1943 
1944 	if (atomic_read(&dev->dev_ordered_sync) == 0)
1945 		return false;
1946 
1947 	spin_lock(&dev->delayed_cmd_lock);
1948 	list_add_tail(&cmd->se_delayed_node, &dev->delayed_cmd_list);
1949 	spin_unlock(&dev->delayed_cmd_lock);
1950 
1951 	pr_debug("Added CDB: 0x%02x Task Attr: 0x%02x to delayed CMD listn",
1952 		cmd->t_task_cdb[0], cmd->sam_task_attr);
1953 	return true;
1954 }
1955 
1956 static int __transport_check_aborted_status(struct se_cmd *, int);
1957 
1958 void target_execute_cmd(struct se_cmd *cmd)
1959 {
1960 	/*
1961 	 * Determine if frontend context caller is requesting the stopping of
1962 	 * this command for frontend exceptions.
1963 	 *
1964 	 * If the received CDB has aleady been aborted stop processing it here.
1965 	 */
1966 	spin_lock_irq(&cmd->t_state_lock);
1967 	if (__transport_check_aborted_status(cmd, 1)) {
1968 		spin_unlock_irq(&cmd->t_state_lock);
1969 		return;
1970 	}
1971 	if (cmd->transport_state & CMD_T_STOP) {
1972 		pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08llx\n",
1973 			__func__, __LINE__, cmd->tag);
1974 
1975 		spin_unlock_irq(&cmd->t_state_lock);
1976 		complete_all(&cmd->t_transport_stop_comp);
1977 		return;
1978 	}
1979 
1980 	cmd->t_state = TRANSPORT_PROCESSING;
1981 	cmd->transport_state &= ~CMD_T_PRE_EXECUTE;
1982 	cmd->transport_state |= CMD_T_ACTIVE | CMD_T_SENT;
1983 	spin_unlock_irq(&cmd->t_state_lock);
1984 
1985 	if (target_write_prot_action(cmd))
1986 		return;
1987 
1988 	if (target_handle_task_attr(cmd)) {
1989 		spin_lock_irq(&cmd->t_state_lock);
1990 		cmd->transport_state &= ~CMD_T_SENT;
1991 		spin_unlock_irq(&cmd->t_state_lock);
1992 		return;
1993 	}
1994 
1995 	__target_execute_cmd(cmd, true);
1996 }
1997 EXPORT_SYMBOL(target_execute_cmd);
1998 
1999 /*
2000  * Process all commands up to the last received ORDERED task attribute which
2001  * requires another blocking boundary
2002  */
2003 static void target_restart_delayed_cmds(struct se_device *dev)
2004 {
2005 	for (;;) {
2006 		struct se_cmd *cmd;
2007 
2008 		spin_lock(&dev->delayed_cmd_lock);
2009 		if (list_empty(&dev->delayed_cmd_list)) {
2010 			spin_unlock(&dev->delayed_cmd_lock);
2011 			break;
2012 		}
2013 
2014 		cmd = list_entry(dev->delayed_cmd_list.next,
2015 				 struct se_cmd, se_delayed_node);
2016 		list_del(&cmd->se_delayed_node);
2017 		spin_unlock(&dev->delayed_cmd_lock);
2018 
2019 		cmd->transport_state |= CMD_T_SENT;
2020 
2021 		__target_execute_cmd(cmd, true);
2022 
2023 		if (cmd->sam_task_attr == TCM_ORDERED_TAG)
2024 			break;
2025 	}
2026 }
2027 
2028 /*
2029  * Called from I/O completion to determine which dormant/delayed
2030  * and ordered cmds need to have their tasks added to the execution queue.
2031  */
2032 static void transport_complete_task_attr(struct se_cmd *cmd)
2033 {
2034 	struct se_device *dev = cmd->se_dev;
2035 
2036 	if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
2037 		return;
2038 
2039 	if (!(cmd->se_cmd_flags & SCF_TASK_ATTR_SET))
2040 		goto restart;
2041 
2042 	if (cmd->sam_task_attr == TCM_SIMPLE_TAG) {
2043 		atomic_dec_mb(&dev->simple_cmds);
2044 		dev->dev_cur_ordered_id++;
2045 	} else if (cmd->sam_task_attr == TCM_HEAD_TAG) {
2046 		dev->dev_cur_ordered_id++;
2047 		pr_debug("Incremented dev_cur_ordered_id: %u for HEAD_OF_QUEUE\n",
2048 			 dev->dev_cur_ordered_id);
2049 	} else if (cmd->sam_task_attr == TCM_ORDERED_TAG) {
2050 		atomic_dec_mb(&dev->dev_ordered_sync);
2051 
2052 		dev->dev_cur_ordered_id++;
2053 		pr_debug("Incremented dev_cur_ordered_id: %u for ORDERED\n",
2054 			 dev->dev_cur_ordered_id);
2055 	}
2056 	cmd->se_cmd_flags &= ~SCF_TASK_ATTR_SET;
2057 
2058 restart:
2059 	target_restart_delayed_cmds(dev);
2060 }
2061 
2062 static void transport_complete_qf(struct se_cmd *cmd)
2063 {
2064 	int ret = 0;
2065 
2066 	transport_complete_task_attr(cmd);
2067 	/*
2068 	 * If a fabric driver ->write_pending() or ->queue_data_in() callback
2069 	 * has returned neither -ENOMEM or -EAGAIN, assume it's fatal and
2070 	 * the same callbacks should not be retried.  Return CHECK_CONDITION
2071 	 * if a scsi_status is not already set.
2072 	 *
2073 	 * If a fabric driver ->queue_status() has returned non zero, always
2074 	 * keep retrying no matter what..
2075 	 */
2076 	if (cmd->t_state == TRANSPORT_COMPLETE_QF_ERR) {
2077 		if (cmd->scsi_status)
2078 			goto queue_status;
2079 
2080 		cmd->se_cmd_flags |= SCF_EMULATED_TASK_SENSE;
2081 		cmd->scsi_status = SAM_STAT_CHECK_CONDITION;
2082 		cmd->scsi_sense_length  = TRANSPORT_SENSE_BUFFER;
2083 		translate_sense_reason(cmd, TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE);
2084 		goto queue_status;
2085 	}
2086 
2087 	if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE)
2088 		goto queue_status;
2089 
2090 	switch (cmd->data_direction) {
2091 	case DMA_FROM_DEVICE:
2092 		if (cmd->scsi_status)
2093 			goto queue_status;
2094 
2095 		trace_target_cmd_complete(cmd);
2096 		ret = cmd->se_tfo->queue_data_in(cmd);
2097 		break;
2098 	case DMA_TO_DEVICE:
2099 		if (cmd->se_cmd_flags & SCF_BIDI) {
2100 			ret = cmd->se_tfo->queue_data_in(cmd);
2101 			break;
2102 		}
2103 		/* fall through */
2104 	case DMA_NONE:
2105 queue_status:
2106 		trace_target_cmd_complete(cmd);
2107 		ret = cmd->se_tfo->queue_status(cmd);
2108 		break;
2109 	default:
2110 		break;
2111 	}
2112 
2113 	if (ret < 0) {
2114 		transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
2115 		return;
2116 	}
2117 	transport_lun_remove_cmd(cmd);
2118 	transport_cmd_check_stop_to_fabric(cmd);
2119 }
2120 
2121 static void transport_handle_queue_full(struct se_cmd *cmd, struct se_device *dev,
2122 					int err, bool write_pending)
2123 {
2124 	/*
2125 	 * -EAGAIN or -ENOMEM signals retry of ->write_pending() and/or
2126 	 * ->queue_data_in() callbacks from new process context.
2127 	 *
2128 	 * Otherwise for other errors, transport_complete_qf() will send
2129 	 * CHECK_CONDITION via ->queue_status() instead of attempting to
2130 	 * retry associated fabric driver data-transfer callbacks.
2131 	 */
2132 	if (err == -EAGAIN || err == -ENOMEM) {
2133 		cmd->t_state = (write_pending) ? TRANSPORT_COMPLETE_QF_WP :
2134 						 TRANSPORT_COMPLETE_QF_OK;
2135 	} else {
2136 		pr_warn_ratelimited("Got unknown fabric queue status: %d\n", err);
2137 		cmd->t_state = TRANSPORT_COMPLETE_QF_ERR;
2138 	}
2139 
2140 	spin_lock_irq(&dev->qf_cmd_lock);
2141 	list_add_tail(&cmd->se_qf_node, &cmd->se_dev->qf_cmd_list);
2142 	atomic_inc_mb(&dev->dev_qf_count);
2143 	spin_unlock_irq(&cmd->se_dev->qf_cmd_lock);
2144 
2145 	schedule_work(&cmd->se_dev->qf_work_queue);
2146 }
2147 
2148 static bool target_read_prot_action(struct se_cmd *cmd)
2149 {
2150 	switch (cmd->prot_op) {
2151 	case TARGET_PROT_DIN_STRIP:
2152 		if (!(cmd->se_sess->sup_prot_ops & TARGET_PROT_DIN_STRIP)) {
2153 			u32 sectors = cmd->data_length >>
2154 				  ilog2(cmd->se_dev->dev_attrib.block_size);
2155 
2156 			cmd->pi_err = sbc_dif_verify(cmd, cmd->t_task_lba,
2157 						     sectors, 0, cmd->t_prot_sg,
2158 						     0);
2159 			if (cmd->pi_err)
2160 				return true;
2161 		}
2162 		break;
2163 	case TARGET_PROT_DIN_INSERT:
2164 		if (cmd->se_sess->sup_prot_ops & TARGET_PROT_DIN_INSERT)
2165 			break;
2166 
2167 		sbc_dif_generate(cmd);
2168 		break;
2169 	default:
2170 		break;
2171 	}
2172 
2173 	return false;
2174 }
2175 
2176 static void target_complete_ok_work(struct work_struct *work)
2177 {
2178 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
2179 	int ret;
2180 
2181 	/*
2182 	 * Check if we need to move delayed/dormant tasks from cmds on the
2183 	 * delayed execution list after a HEAD_OF_QUEUE or ORDERED Task
2184 	 * Attribute.
2185 	 */
2186 	transport_complete_task_attr(cmd);
2187 
2188 	/*
2189 	 * Check to schedule QUEUE_FULL work, or execute an existing
2190 	 * cmd->transport_qf_callback()
2191 	 */
2192 	if (atomic_read(&cmd->se_dev->dev_qf_count) != 0)
2193 		schedule_work(&cmd->se_dev->qf_work_queue);
2194 
2195 	/*
2196 	 * Check if we need to send a sense buffer from
2197 	 * the struct se_cmd in question.
2198 	 */
2199 	if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) {
2200 		WARN_ON(!cmd->scsi_status);
2201 		ret = transport_send_check_condition_and_sense(
2202 					cmd, 0, 1);
2203 		if (ret)
2204 			goto queue_full;
2205 
2206 		transport_lun_remove_cmd(cmd);
2207 		transport_cmd_check_stop_to_fabric(cmd);
2208 		return;
2209 	}
2210 	/*
2211 	 * Check for a callback, used by amongst other things
2212 	 * XDWRITE_READ_10 and COMPARE_AND_WRITE emulation.
2213 	 */
2214 	if (cmd->transport_complete_callback) {
2215 		sense_reason_t rc;
2216 		bool caw = (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE);
2217 		bool zero_dl = !(cmd->data_length);
2218 		int post_ret = 0;
2219 
2220 		rc = cmd->transport_complete_callback(cmd, true, &post_ret);
2221 		if (!rc && !post_ret) {
2222 			if (caw && zero_dl)
2223 				goto queue_rsp;
2224 
2225 			return;
2226 		} else if (rc) {
2227 			ret = transport_send_check_condition_and_sense(cmd,
2228 						rc, 0);
2229 			if (ret)
2230 				goto queue_full;
2231 
2232 			transport_lun_remove_cmd(cmd);
2233 			transport_cmd_check_stop_to_fabric(cmd);
2234 			return;
2235 		}
2236 	}
2237 
2238 queue_rsp:
2239 	switch (cmd->data_direction) {
2240 	case DMA_FROM_DEVICE:
2241 		if (cmd->scsi_status)
2242 			goto queue_status;
2243 
2244 		atomic_long_add(cmd->data_length,
2245 				&cmd->se_lun->lun_stats.tx_data_octets);
2246 		/*
2247 		 * Perform READ_STRIP of PI using software emulation when
2248 		 * backend had PI enabled, if the transport will not be
2249 		 * performing hardware READ_STRIP offload.
2250 		 */
2251 		if (target_read_prot_action(cmd)) {
2252 			ret = transport_send_check_condition_and_sense(cmd,
2253 						cmd->pi_err, 0);
2254 			if (ret)
2255 				goto queue_full;
2256 
2257 			transport_lun_remove_cmd(cmd);
2258 			transport_cmd_check_stop_to_fabric(cmd);
2259 			return;
2260 		}
2261 
2262 		trace_target_cmd_complete(cmd);
2263 		ret = cmd->se_tfo->queue_data_in(cmd);
2264 		if (ret)
2265 			goto queue_full;
2266 		break;
2267 	case DMA_TO_DEVICE:
2268 		atomic_long_add(cmd->data_length,
2269 				&cmd->se_lun->lun_stats.rx_data_octets);
2270 		/*
2271 		 * Check if we need to send READ payload for BIDI-COMMAND
2272 		 */
2273 		if (cmd->se_cmd_flags & SCF_BIDI) {
2274 			atomic_long_add(cmd->data_length,
2275 					&cmd->se_lun->lun_stats.tx_data_octets);
2276 			ret = cmd->se_tfo->queue_data_in(cmd);
2277 			if (ret)
2278 				goto queue_full;
2279 			break;
2280 		}
2281 		/* fall through */
2282 	case DMA_NONE:
2283 queue_status:
2284 		trace_target_cmd_complete(cmd);
2285 		ret = cmd->se_tfo->queue_status(cmd);
2286 		if (ret)
2287 			goto queue_full;
2288 		break;
2289 	default:
2290 		break;
2291 	}
2292 
2293 	transport_lun_remove_cmd(cmd);
2294 	transport_cmd_check_stop_to_fabric(cmd);
2295 	return;
2296 
2297 queue_full:
2298 	pr_debug("Handling complete_ok QUEUE_FULL: se_cmd: %p,"
2299 		" data_direction: %d\n", cmd, cmd->data_direction);
2300 
2301 	transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
2302 }
2303 
2304 void target_free_sgl(struct scatterlist *sgl, int nents)
2305 {
2306 	sgl_free_n_order(sgl, nents, 0);
2307 }
2308 EXPORT_SYMBOL(target_free_sgl);
2309 
2310 static inline void transport_reset_sgl_orig(struct se_cmd *cmd)
2311 {
2312 	/*
2313 	 * Check for saved t_data_sg that may be used for COMPARE_AND_WRITE
2314 	 * emulation, and free + reset pointers if necessary..
2315 	 */
2316 	if (!cmd->t_data_sg_orig)
2317 		return;
2318 
2319 	kfree(cmd->t_data_sg);
2320 	cmd->t_data_sg = cmd->t_data_sg_orig;
2321 	cmd->t_data_sg_orig = NULL;
2322 	cmd->t_data_nents = cmd->t_data_nents_orig;
2323 	cmd->t_data_nents_orig = 0;
2324 }
2325 
2326 static inline void transport_free_pages(struct se_cmd *cmd)
2327 {
2328 	if (!(cmd->se_cmd_flags & SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC)) {
2329 		target_free_sgl(cmd->t_prot_sg, cmd->t_prot_nents);
2330 		cmd->t_prot_sg = NULL;
2331 		cmd->t_prot_nents = 0;
2332 	}
2333 
2334 	if (cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) {
2335 		/*
2336 		 * Release special case READ buffer payload required for
2337 		 * SG_TO_MEM_NOALLOC to function with COMPARE_AND_WRITE
2338 		 */
2339 		if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) {
2340 			target_free_sgl(cmd->t_bidi_data_sg,
2341 					   cmd->t_bidi_data_nents);
2342 			cmd->t_bidi_data_sg = NULL;
2343 			cmd->t_bidi_data_nents = 0;
2344 		}
2345 		transport_reset_sgl_orig(cmd);
2346 		return;
2347 	}
2348 	transport_reset_sgl_orig(cmd);
2349 
2350 	target_free_sgl(cmd->t_data_sg, cmd->t_data_nents);
2351 	cmd->t_data_sg = NULL;
2352 	cmd->t_data_nents = 0;
2353 
2354 	target_free_sgl(cmd->t_bidi_data_sg, cmd->t_bidi_data_nents);
2355 	cmd->t_bidi_data_sg = NULL;
2356 	cmd->t_bidi_data_nents = 0;
2357 }
2358 
2359 void *transport_kmap_data_sg(struct se_cmd *cmd)
2360 {
2361 	struct scatterlist *sg = cmd->t_data_sg;
2362 	struct page **pages;
2363 	int i;
2364 
2365 	/*
2366 	 * We need to take into account a possible offset here for fabrics like
2367 	 * tcm_loop who may be using a contig buffer from the SCSI midlayer for
2368 	 * control CDBs passed as SGLs via transport_generic_map_mem_to_cmd()
2369 	 */
2370 	if (!cmd->t_data_nents)
2371 		return NULL;
2372 
2373 	BUG_ON(!sg);
2374 	if (cmd->t_data_nents == 1)
2375 		return kmap(sg_page(sg)) + sg->offset;
2376 
2377 	/* >1 page. use vmap */
2378 	pages = kmalloc_array(cmd->t_data_nents, sizeof(*pages), GFP_KERNEL);
2379 	if (!pages)
2380 		return NULL;
2381 
2382 	/* convert sg[] to pages[] */
2383 	for_each_sg(cmd->t_data_sg, sg, cmd->t_data_nents, i) {
2384 		pages[i] = sg_page(sg);
2385 	}
2386 
2387 	cmd->t_data_vmap = vmap(pages, cmd->t_data_nents,  VM_MAP, PAGE_KERNEL);
2388 	kfree(pages);
2389 	if (!cmd->t_data_vmap)
2390 		return NULL;
2391 
2392 	return cmd->t_data_vmap + cmd->t_data_sg[0].offset;
2393 }
2394 EXPORT_SYMBOL(transport_kmap_data_sg);
2395 
2396 void transport_kunmap_data_sg(struct se_cmd *cmd)
2397 {
2398 	if (!cmd->t_data_nents) {
2399 		return;
2400 	} else if (cmd->t_data_nents == 1) {
2401 		kunmap(sg_page(cmd->t_data_sg));
2402 		return;
2403 	}
2404 
2405 	vunmap(cmd->t_data_vmap);
2406 	cmd->t_data_vmap = NULL;
2407 }
2408 EXPORT_SYMBOL(transport_kunmap_data_sg);
2409 
2410 int
2411 target_alloc_sgl(struct scatterlist **sgl, unsigned int *nents, u32 length,
2412 		 bool zero_page, bool chainable)
2413 {
2414 	gfp_t gfp = GFP_KERNEL | (zero_page ? __GFP_ZERO : 0);
2415 
2416 	*sgl = sgl_alloc_order(length, 0, chainable, gfp, nents);
2417 	return *sgl ? 0 : -ENOMEM;
2418 }
2419 EXPORT_SYMBOL(target_alloc_sgl);
2420 
2421 /*
2422  * Allocate any required resources to execute the command.  For writes we
2423  * might not have the payload yet, so notify the fabric via a call to
2424  * ->write_pending instead. Otherwise place it on the execution queue.
2425  */
2426 sense_reason_t
2427 transport_generic_new_cmd(struct se_cmd *cmd)
2428 {
2429 	unsigned long flags;
2430 	int ret = 0;
2431 	bool zero_flag = !(cmd->se_cmd_flags & SCF_SCSI_DATA_CDB);
2432 
2433 	if (cmd->prot_op != TARGET_PROT_NORMAL &&
2434 	    !(cmd->se_cmd_flags & SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC)) {
2435 		ret = target_alloc_sgl(&cmd->t_prot_sg, &cmd->t_prot_nents,
2436 				       cmd->prot_length, true, false);
2437 		if (ret < 0)
2438 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2439 	}
2440 
2441 	/*
2442 	 * Determine is the TCM fabric module has already allocated physical
2443 	 * memory, and is directly calling transport_generic_map_mem_to_cmd()
2444 	 * beforehand.
2445 	 */
2446 	if (!(cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) &&
2447 	    cmd->data_length) {
2448 
2449 		if ((cmd->se_cmd_flags & SCF_BIDI) ||
2450 		    (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE)) {
2451 			u32 bidi_length;
2452 
2453 			if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE)
2454 				bidi_length = cmd->t_task_nolb *
2455 					      cmd->se_dev->dev_attrib.block_size;
2456 			else
2457 				bidi_length = cmd->data_length;
2458 
2459 			ret = target_alloc_sgl(&cmd->t_bidi_data_sg,
2460 					       &cmd->t_bidi_data_nents,
2461 					       bidi_length, zero_flag, false);
2462 			if (ret < 0)
2463 				return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2464 		}
2465 
2466 		ret = target_alloc_sgl(&cmd->t_data_sg, &cmd->t_data_nents,
2467 				       cmd->data_length, zero_flag, false);
2468 		if (ret < 0)
2469 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2470 	} else if ((cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) &&
2471 		    cmd->data_length) {
2472 		/*
2473 		 * Special case for COMPARE_AND_WRITE with fabrics
2474 		 * using SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC.
2475 		 */
2476 		u32 caw_length = cmd->t_task_nolb *
2477 				 cmd->se_dev->dev_attrib.block_size;
2478 
2479 		ret = target_alloc_sgl(&cmd->t_bidi_data_sg,
2480 				       &cmd->t_bidi_data_nents,
2481 				       caw_length, zero_flag, false);
2482 		if (ret < 0)
2483 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2484 	}
2485 	/*
2486 	 * If this command is not a write we can execute it right here,
2487 	 * for write buffers we need to notify the fabric driver first
2488 	 * and let it call back once the write buffers are ready.
2489 	 */
2490 	target_add_to_state_list(cmd);
2491 	if (cmd->data_direction != DMA_TO_DEVICE || cmd->data_length == 0) {
2492 		target_execute_cmd(cmd);
2493 		return 0;
2494 	}
2495 
2496 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2497 	cmd->t_state = TRANSPORT_WRITE_PENDING;
2498 	/*
2499 	 * Determine if frontend context caller is requesting the stopping of
2500 	 * this command for frontend exceptions.
2501 	 */
2502 	if (cmd->transport_state & CMD_T_STOP) {
2503 		pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08llx\n",
2504 			 __func__, __LINE__, cmd->tag);
2505 
2506 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2507 
2508 		complete_all(&cmd->t_transport_stop_comp);
2509 		return 0;
2510 	}
2511 	cmd->transport_state &= ~CMD_T_ACTIVE;
2512 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2513 
2514 	ret = cmd->se_tfo->write_pending(cmd);
2515 	if (ret)
2516 		goto queue_full;
2517 
2518 	return 0;
2519 
2520 queue_full:
2521 	pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n", cmd);
2522 	transport_handle_queue_full(cmd, cmd->se_dev, ret, true);
2523 	return 0;
2524 }
2525 EXPORT_SYMBOL(transport_generic_new_cmd);
2526 
2527 static void transport_write_pending_qf(struct se_cmd *cmd)
2528 {
2529 	unsigned long flags;
2530 	int ret;
2531 	bool stop;
2532 
2533 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2534 	stop = (cmd->transport_state & (CMD_T_STOP | CMD_T_ABORTED));
2535 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2536 
2537 	if (stop) {
2538 		pr_debug("%s:%d CMD_T_STOP|CMD_T_ABORTED for ITT: 0x%08llx\n",
2539 			__func__, __LINE__, cmd->tag);
2540 		complete_all(&cmd->t_transport_stop_comp);
2541 		return;
2542 	}
2543 
2544 	ret = cmd->se_tfo->write_pending(cmd);
2545 	if (ret) {
2546 		pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n",
2547 			 cmd);
2548 		transport_handle_queue_full(cmd, cmd->se_dev, ret, true);
2549 	}
2550 }
2551 
2552 static bool
2553 __transport_wait_for_tasks(struct se_cmd *, bool, bool *, bool *,
2554 			   unsigned long *flags);
2555 
2556 static void target_wait_free_cmd(struct se_cmd *cmd, bool *aborted, bool *tas)
2557 {
2558 	unsigned long flags;
2559 
2560 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2561 	__transport_wait_for_tasks(cmd, true, aborted, tas, &flags);
2562 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2563 }
2564 
2565 int transport_generic_free_cmd(struct se_cmd *cmd, int wait_for_tasks)
2566 {
2567 	int ret = 0;
2568 	bool aborted = false, tas = false;
2569 
2570 	if (!(cmd->se_cmd_flags & SCF_SE_LUN_CMD)) {
2571 		if (wait_for_tasks && (cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
2572 			target_wait_free_cmd(cmd, &aborted, &tas);
2573 
2574 		if (!aborted || tas)
2575 			ret = target_put_sess_cmd(cmd);
2576 	} else {
2577 		if (wait_for_tasks)
2578 			target_wait_free_cmd(cmd, &aborted, &tas);
2579 		/*
2580 		 * Handle WRITE failure case where transport_generic_new_cmd()
2581 		 * has already added se_cmd to state_list, but fabric has
2582 		 * failed command before I/O submission.
2583 		 */
2584 		if (cmd->state_active)
2585 			target_remove_from_state_list(cmd);
2586 
2587 		if (cmd->se_lun)
2588 			transport_lun_remove_cmd(cmd);
2589 
2590 		if (!aborted || tas)
2591 			ret = target_put_sess_cmd(cmd);
2592 	}
2593 	/*
2594 	 * If the task has been internally aborted due to TMR ABORT_TASK
2595 	 * or LUN_RESET, target_core_tmr.c is responsible for performing
2596 	 * the remaining calls to target_put_sess_cmd(), and not the
2597 	 * callers of this function.
2598 	 */
2599 	if (aborted) {
2600 		pr_debug("Detected CMD_T_ABORTED for ITT: %llu\n", cmd->tag);
2601 		wait_for_completion(&cmd->cmd_wait_comp);
2602 		cmd->se_tfo->release_cmd(cmd);
2603 		ret = 1;
2604 	}
2605 	return ret;
2606 }
2607 EXPORT_SYMBOL(transport_generic_free_cmd);
2608 
2609 /* target_get_sess_cmd - Add command to active ->sess_cmd_list
2610  * @se_cmd:	command descriptor to add
2611  * @ack_kref:	Signal that fabric will perform an ack target_put_sess_cmd()
2612  */
2613 int target_get_sess_cmd(struct se_cmd *se_cmd, bool ack_kref)
2614 {
2615 	struct se_session *se_sess = se_cmd->se_sess;
2616 	unsigned long flags;
2617 	int ret = 0;
2618 
2619 	/*
2620 	 * Add a second kref if the fabric caller is expecting to handle
2621 	 * fabric acknowledgement that requires two target_put_sess_cmd()
2622 	 * invocations before se_cmd descriptor release.
2623 	 */
2624 	if (ack_kref) {
2625 		if (!kref_get_unless_zero(&se_cmd->cmd_kref))
2626 			return -EINVAL;
2627 
2628 		se_cmd->se_cmd_flags |= SCF_ACK_KREF;
2629 	}
2630 
2631 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2632 	if (se_sess->sess_tearing_down) {
2633 		ret = -ESHUTDOWN;
2634 		goto out;
2635 	}
2636 	se_cmd->transport_state |= CMD_T_PRE_EXECUTE;
2637 	list_add_tail(&se_cmd->se_cmd_list, &se_sess->sess_cmd_list);
2638 out:
2639 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2640 
2641 	if (ret && ack_kref)
2642 		target_put_sess_cmd(se_cmd);
2643 
2644 	return ret;
2645 }
2646 EXPORT_SYMBOL(target_get_sess_cmd);
2647 
2648 static void target_free_cmd_mem(struct se_cmd *cmd)
2649 {
2650 	transport_free_pages(cmd);
2651 
2652 	if (cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
2653 		core_tmr_release_req(cmd->se_tmr_req);
2654 	if (cmd->t_task_cdb != cmd->__t_task_cdb)
2655 		kfree(cmd->t_task_cdb);
2656 }
2657 
2658 static void target_release_cmd_kref(struct kref *kref)
2659 {
2660 	struct se_cmd *se_cmd = container_of(kref, struct se_cmd, cmd_kref);
2661 	struct se_session *se_sess = se_cmd->se_sess;
2662 	unsigned long flags;
2663 	bool fabric_stop;
2664 
2665 	if (se_sess) {
2666 		spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2667 
2668 		spin_lock(&se_cmd->t_state_lock);
2669 		fabric_stop = (se_cmd->transport_state & CMD_T_FABRIC_STOP) &&
2670 			      (se_cmd->transport_state & CMD_T_ABORTED);
2671 		spin_unlock(&se_cmd->t_state_lock);
2672 
2673 		if (se_cmd->cmd_wait_set || fabric_stop) {
2674 			list_del_init(&se_cmd->se_cmd_list);
2675 			spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2676 			target_free_cmd_mem(se_cmd);
2677 			complete(&se_cmd->cmd_wait_comp);
2678 			return;
2679 		}
2680 		list_del_init(&se_cmd->se_cmd_list);
2681 		spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2682 	}
2683 
2684 	target_free_cmd_mem(se_cmd);
2685 	se_cmd->se_tfo->release_cmd(se_cmd);
2686 }
2687 
2688 /**
2689  * target_put_sess_cmd - decrease the command reference count
2690  * @se_cmd:	command to drop a reference from
2691  *
2692  * Returns 1 if and only if this target_put_sess_cmd() call caused the
2693  * refcount to drop to zero. Returns zero otherwise.
2694  */
2695 int target_put_sess_cmd(struct se_cmd *se_cmd)
2696 {
2697 	return kref_put(&se_cmd->cmd_kref, target_release_cmd_kref);
2698 }
2699 EXPORT_SYMBOL(target_put_sess_cmd);
2700 
2701 static const char *data_dir_name(enum dma_data_direction d)
2702 {
2703 	switch (d) {
2704 	case DMA_BIDIRECTIONAL:	return "BIDI";
2705 	case DMA_TO_DEVICE:	return "WRITE";
2706 	case DMA_FROM_DEVICE:	return "READ";
2707 	case DMA_NONE:		return "NONE";
2708 	}
2709 
2710 	return "(?)";
2711 }
2712 
2713 static const char *cmd_state_name(enum transport_state_table t)
2714 {
2715 	switch (t) {
2716 	case TRANSPORT_NO_STATE:	return "NO_STATE";
2717 	case TRANSPORT_NEW_CMD:		return "NEW_CMD";
2718 	case TRANSPORT_WRITE_PENDING:	return "WRITE_PENDING";
2719 	case TRANSPORT_PROCESSING:	return "PROCESSING";
2720 	case TRANSPORT_COMPLETE:	return "COMPLETE";
2721 	case TRANSPORT_ISTATE_PROCESSING:
2722 					return "ISTATE_PROCESSING";
2723 	case TRANSPORT_COMPLETE_QF_WP:	return "COMPLETE_QF_WP";
2724 	case TRANSPORT_COMPLETE_QF_OK:	return "COMPLETE_QF_OK";
2725 	case TRANSPORT_COMPLETE_QF_ERR:	return "COMPLETE_QF_ERR";
2726 	}
2727 
2728 	return "(?)";
2729 }
2730 
2731 static void target_append_str(char **str, const char *txt)
2732 {
2733 	char *prev = *str;
2734 
2735 	*str = *str ? kasprintf(GFP_ATOMIC, "%s,%s", *str, txt) :
2736 		kstrdup(txt, GFP_ATOMIC);
2737 	kfree(prev);
2738 }
2739 
2740 /*
2741  * Convert a transport state bitmask into a string. The caller is
2742  * responsible for freeing the returned pointer.
2743  */
2744 static char *target_ts_to_str(u32 ts)
2745 {
2746 	char *str = NULL;
2747 
2748 	if (ts & CMD_T_ABORTED)
2749 		target_append_str(&str, "aborted");
2750 	if (ts & CMD_T_ACTIVE)
2751 		target_append_str(&str, "active");
2752 	if (ts & CMD_T_COMPLETE)
2753 		target_append_str(&str, "complete");
2754 	if (ts & CMD_T_SENT)
2755 		target_append_str(&str, "sent");
2756 	if (ts & CMD_T_STOP)
2757 		target_append_str(&str, "stop");
2758 	if (ts & CMD_T_FABRIC_STOP)
2759 		target_append_str(&str, "fabric_stop");
2760 
2761 	return str;
2762 }
2763 
2764 static const char *target_tmf_name(enum tcm_tmreq_table tmf)
2765 {
2766 	switch (tmf) {
2767 	case TMR_ABORT_TASK:		return "ABORT_TASK";
2768 	case TMR_ABORT_TASK_SET:	return "ABORT_TASK_SET";
2769 	case TMR_CLEAR_ACA:		return "CLEAR_ACA";
2770 	case TMR_CLEAR_TASK_SET:	return "CLEAR_TASK_SET";
2771 	case TMR_LUN_RESET:		return "LUN_RESET";
2772 	case TMR_TARGET_WARM_RESET:	return "TARGET_WARM_RESET";
2773 	case TMR_TARGET_COLD_RESET:	return "TARGET_COLD_RESET";
2774 	case TMR_UNKNOWN:		break;
2775 	}
2776 	return "(?)";
2777 }
2778 
2779 void target_show_cmd(const char *pfx, struct se_cmd *cmd)
2780 {
2781 	char *ts_str = target_ts_to_str(cmd->transport_state);
2782 	const u8 *cdb = cmd->t_task_cdb;
2783 	struct se_tmr_req *tmf = cmd->se_tmr_req;
2784 
2785 	if (!(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)) {
2786 		pr_debug("%scmd %#02x:%#02x with tag %#llx dir %s i_state %d t_state %s len %d refcnt %d transport_state %s\n",
2787 			 pfx, cdb[0], cdb[1], cmd->tag,
2788 			 data_dir_name(cmd->data_direction),
2789 			 cmd->se_tfo->get_cmd_state(cmd),
2790 			 cmd_state_name(cmd->t_state), cmd->data_length,
2791 			 kref_read(&cmd->cmd_kref), ts_str);
2792 	} else {
2793 		pr_debug("%stmf %s with tag %#llx ref_task_tag %#llx i_state %d t_state %s refcnt %d transport_state %s\n",
2794 			 pfx, target_tmf_name(tmf->function), cmd->tag,
2795 			 tmf->ref_task_tag, cmd->se_tfo->get_cmd_state(cmd),
2796 			 cmd_state_name(cmd->t_state),
2797 			 kref_read(&cmd->cmd_kref), ts_str);
2798 	}
2799 	kfree(ts_str);
2800 }
2801 EXPORT_SYMBOL(target_show_cmd);
2802 
2803 /* target_sess_cmd_list_set_waiting - Flag all commands in
2804  *         sess_cmd_list to complete cmd_wait_comp.  Set
2805  *         sess_tearing_down so no more commands are queued.
2806  * @se_sess:	session to flag
2807  */
2808 void target_sess_cmd_list_set_waiting(struct se_session *se_sess)
2809 {
2810 	struct se_cmd *se_cmd, *tmp_cmd;
2811 	unsigned long flags;
2812 	int rc;
2813 
2814 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2815 	if (se_sess->sess_tearing_down) {
2816 		spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2817 		return;
2818 	}
2819 	se_sess->sess_tearing_down = 1;
2820 	list_splice_init(&se_sess->sess_cmd_list, &se_sess->sess_wait_list);
2821 
2822 	list_for_each_entry_safe(se_cmd, tmp_cmd,
2823 				 &se_sess->sess_wait_list, se_cmd_list) {
2824 		rc = kref_get_unless_zero(&se_cmd->cmd_kref);
2825 		if (rc) {
2826 			se_cmd->cmd_wait_set = 1;
2827 			spin_lock(&se_cmd->t_state_lock);
2828 			se_cmd->transport_state |= CMD_T_FABRIC_STOP;
2829 			spin_unlock(&se_cmd->t_state_lock);
2830 		} else
2831 			list_del_init(&se_cmd->se_cmd_list);
2832 	}
2833 
2834 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2835 }
2836 EXPORT_SYMBOL(target_sess_cmd_list_set_waiting);
2837 
2838 /* target_wait_for_sess_cmds - Wait for outstanding descriptors
2839  * @se_sess:    session to wait for active I/O
2840  */
2841 void target_wait_for_sess_cmds(struct se_session *se_sess)
2842 {
2843 	struct se_cmd *se_cmd, *tmp_cmd;
2844 	unsigned long flags;
2845 	bool tas;
2846 
2847 	list_for_each_entry_safe(se_cmd, tmp_cmd,
2848 				&se_sess->sess_wait_list, se_cmd_list) {
2849 		pr_debug("Waiting for se_cmd: %p t_state: %d, fabric state:"
2850 			" %d\n", se_cmd, se_cmd->t_state,
2851 			se_cmd->se_tfo->get_cmd_state(se_cmd));
2852 
2853 		spin_lock_irqsave(&se_cmd->t_state_lock, flags);
2854 		tas = (se_cmd->transport_state & CMD_T_TAS);
2855 		spin_unlock_irqrestore(&se_cmd->t_state_lock, flags);
2856 
2857 		if (!target_put_sess_cmd(se_cmd)) {
2858 			if (tas)
2859 				target_put_sess_cmd(se_cmd);
2860 		}
2861 
2862 		wait_for_completion(&se_cmd->cmd_wait_comp);
2863 		pr_debug("After cmd_wait_comp: se_cmd: %p t_state: %d"
2864 			" fabric state: %d\n", se_cmd, se_cmd->t_state,
2865 			se_cmd->se_tfo->get_cmd_state(se_cmd));
2866 
2867 		se_cmd->se_tfo->release_cmd(se_cmd);
2868 	}
2869 
2870 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2871 	WARN_ON(!list_empty(&se_sess->sess_cmd_list));
2872 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2873 
2874 }
2875 EXPORT_SYMBOL(target_wait_for_sess_cmds);
2876 
2877 static void target_lun_confirm(struct percpu_ref *ref)
2878 {
2879 	struct se_lun *lun = container_of(ref, struct se_lun, lun_ref);
2880 
2881 	complete(&lun->lun_ref_comp);
2882 }
2883 
2884 void transport_clear_lun_ref(struct se_lun *lun)
2885 {
2886 	/*
2887 	 * Mark the percpu-ref as DEAD, switch to atomic_t mode, drop
2888 	 * the initial reference and schedule confirm kill to be
2889 	 * executed after one full RCU grace period has completed.
2890 	 */
2891 	percpu_ref_kill_and_confirm(&lun->lun_ref, target_lun_confirm);
2892 	/*
2893 	 * The first completion waits for percpu_ref_switch_to_atomic_rcu()
2894 	 * to call target_lun_confirm after lun->lun_ref has been marked
2895 	 * as __PERCPU_REF_DEAD on all CPUs, and switches to atomic_t
2896 	 * mode so that percpu_ref_tryget_live() lookup of lun->lun_ref
2897 	 * fails for all new incoming I/O.
2898 	 */
2899 	wait_for_completion(&lun->lun_ref_comp);
2900 	/*
2901 	 * The second completion waits for percpu_ref_put_many() to
2902 	 * invoke ->release() after lun->lun_ref has switched to
2903 	 * atomic_t mode, and lun->lun_ref.count has reached zero.
2904 	 *
2905 	 * At this point all target-core lun->lun_ref references have
2906 	 * been dropped via transport_lun_remove_cmd(), and it's safe
2907 	 * to proceed with the remaining LUN shutdown.
2908 	 */
2909 	wait_for_completion(&lun->lun_shutdown_comp);
2910 }
2911 
2912 static bool
2913 __transport_wait_for_tasks(struct se_cmd *cmd, bool fabric_stop,
2914 			   bool *aborted, bool *tas, unsigned long *flags)
2915 	__releases(&cmd->t_state_lock)
2916 	__acquires(&cmd->t_state_lock)
2917 {
2918 
2919 	assert_spin_locked(&cmd->t_state_lock);
2920 	WARN_ON_ONCE(!irqs_disabled());
2921 
2922 	if (fabric_stop)
2923 		cmd->transport_state |= CMD_T_FABRIC_STOP;
2924 
2925 	if (cmd->transport_state & CMD_T_ABORTED)
2926 		*aborted = true;
2927 
2928 	if (cmd->transport_state & CMD_T_TAS)
2929 		*tas = true;
2930 
2931 	if (!(cmd->se_cmd_flags & SCF_SE_LUN_CMD) &&
2932 	    !(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
2933 		return false;
2934 
2935 	if (!(cmd->se_cmd_flags & SCF_SUPPORTED_SAM_OPCODE) &&
2936 	    !(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
2937 		return false;
2938 
2939 	if (!(cmd->transport_state & CMD_T_ACTIVE))
2940 		return false;
2941 
2942 	if (fabric_stop && *aborted)
2943 		return false;
2944 
2945 	cmd->transport_state |= CMD_T_STOP;
2946 
2947 	target_show_cmd("wait_for_tasks: Stopping ", cmd);
2948 
2949 	spin_unlock_irqrestore(&cmd->t_state_lock, *flags);
2950 
2951 	while (!wait_for_completion_timeout(&cmd->t_transport_stop_comp,
2952 					    180 * HZ))
2953 		target_show_cmd("wait for tasks: ", cmd);
2954 
2955 	spin_lock_irqsave(&cmd->t_state_lock, *flags);
2956 	cmd->transport_state &= ~(CMD_T_ACTIVE | CMD_T_STOP);
2957 
2958 	pr_debug("wait_for_tasks: Stopped wait_for_completion(&cmd->"
2959 		 "t_transport_stop_comp) for ITT: 0x%08llx\n", cmd->tag);
2960 
2961 	return true;
2962 }
2963 
2964 /**
2965  * transport_wait_for_tasks - set CMD_T_STOP and wait for t_transport_stop_comp
2966  * @cmd: command to wait on
2967  */
2968 bool transport_wait_for_tasks(struct se_cmd *cmd)
2969 {
2970 	unsigned long flags;
2971 	bool ret, aborted = false, tas = false;
2972 
2973 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2974 	ret = __transport_wait_for_tasks(cmd, false, &aborted, &tas, &flags);
2975 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2976 
2977 	return ret;
2978 }
2979 EXPORT_SYMBOL(transport_wait_for_tasks);
2980 
2981 struct sense_info {
2982 	u8 key;
2983 	u8 asc;
2984 	u8 ascq;
2985 	bool add_sector_info;
2986 };
2987 
2988 static const struct sense_info sense_info_table[] = {
2989 	[TCM_NO_SENSE] = {
2990 		.key = NOT_READY
2991 	},
2992 	[TCM_NON_EXISTENT_LUN] = {
2993 		.key = ILLEGAL_REQUEST,
2994 		.asc = 0x25 /* LOGICAL UNIT NOT SUPPORTED */
2995 	},
2996 	[TCM_UNSUPPORTED_SCSI_OPCODE] = {
2997 		.key = ILLEGAL_REQUEST,
2998 		.asc = 0x20, /* INVALID COMMAND OPERATION CODE */
2999 	},
3000 	[TCM_SECTOR_COUNT_TOO_MANY] = {
3001 		.key = ILLEGAL_REQUEST,
3002 		.asc = 0x20, /* INVALID COMMAND OPERATION CODE */
3003 	},
3004 	[TCM_UNKNOWN_MODE_PAGE] = {
3005 		.key = ILLEGAL_REQUEST,
3006 		.asc = 0x24, /* INVALID FIELD IN CDB */
3007 	},
3008 	[TCM_CHECK_CONDITION_ABORT_CMD] = {
3009 		.key = ABORTED_COMMAND,
3010 		.asc = 0x29, /* BUS DEVICE RESET FUNCTION OCCURRED */
3011 		.ascq = 0x03,
3012 	},
3013 	[TCM_INCORRECT_AMOUNT_OF_DATA] = {
3014 		.key = ABORTED_COMMAND,
3015 		.asc = 0x0c, /* WRITE ERROR */
3016 		.ascq = 0x0d, /* NOT ENOUGH UNSOLICITED DATA */
3017 	},
3018 	[TCM_INVALID_CDB_FIELD] = {
3019 		.key = ILLEGAL_REQUEST,
3020 		.asc = 0x24, /* INVALID FIELD IN CDB */
3021 	},
3022 	[TCM_INVALID_PARAMETER_LIST] = {
3023 		.key = ILLEGAL_REQUEST,
3024 		.asc = 0x26, /* INVALID FIELD IN PARAMETER LIST */
3025 	},
3026 	[TCM_TOO_MANY_TARGET_DESCS] = {
3027 		.key = ILLEGAL_REQUEST,
3028 		.asc = 0x26,
3029 		.ascq = 0x06, /* TOO MANY TARGET DESCRIPTORS */
3030 	},
3031 	[TCM_UNSUPPORTED_TARGET_DESC_TYPE_CODE] = {
3032 		.key = ILLEGAL_REQUEST,
3033 		.asc = 0x26,
3034 		.ascq = 0x07, /* UNSUPPORTED TARGET DESCRIPTOR TYPE CODE */
3035 	},
3036 	[TCM_TOO_MANY_SEGMENT_DESCS] = {
3037 		.key = ILLEGAL_REQUEST,
3038 		.asc = 0x26,
3039 		.ascq = 0x08, /* TOO MANY SEGMENT DESCRIPTORS */
3040 	},
3041 	[TCM_UNSUPPORTED_SEGMENT_DESC_TYPE_CODE] = {
3042 		.key = ILLEGAL_REQUEST,
3043 		.asc = 0x26,
3044 		.ascq = 0x09, /* UNSUPPORTED SEGMENT DESCRIPTOR TYPE CODE */
3045 	},
3046 	[TCM_PARAMETER_LIST_LENGTH_ERROR] = {
3047 		.key = ILLEGAL_REQUEST,
3048 		.asc = 0x1a, /* PARAMETER LIST LENGTH ERROR */
3049 	},
3050 	[TCM_UNEXPECTED_UNSOLICITED_DATA] = {
3051 		.key = ILLEGAL_REQUEST,
3052 		.asc = 0x0c, /* WRITE ERROR */
3053 		.ascq = 0x0c, /* UNEXPECTED_UNSOLICITED_DATA */
3054 	},
3055 	[TCM_SERVICE_CRC_ERROR] = {
3056 		.key = ABORTED_COMMAND,
3057 		.asc = 0x47, /* PROTOCOL SERVICE CRC ERROR */
3058 		.ascq = 0x05, /* N/A */
3059 	},
3060 	[TCM_SNACK_REJECTED] = {
3061 		.key = ABORTED_COMMAND,
3062 		.asc = 0x11, /* READ ERROR */
3063 		.ascq = 0x13, /* FAILED RETRANSMISSION REQUEST */
3064 	},
3065 	[TCM_WRITE_PROTECTED] = {
3066 		.key = DATA_PROTECT,
3067 		.asc = 0x27, /* WRITE PROTECTED */
3068 	},
3069 	[TCM_ADDRESS_OUT_OF_RANGE] = {
3070 		.key = ILLEGAL_REQUEST,
3071 		.asc = 0x21, /* LOGICAL BLOCK ADDRESS OUT OF RANGE */
3072 	},
3073 	[TCM_CHECK_CONDITION_UNIT_ATTENTION] = {
3074 		.key = UNIT_ATTENTION,
3075 	},
3076 	[TCM_CHECK_CONDITION_NOT_READY] = {
3077 		.key = NOT_READY,
3078 	},
3079 	[TCM_MISCOMPARE_VERIFY] = {
3080 		.key = MISCOMPARE,
3081 		.asc = 0x1d, /* MISCOMPARE DURING VERIFY OPERATION */
3082 		.ascq = 0x00,
3083 	},
3084 	[TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED] = {
3085 		.key = ABORTED_COMMAND,
3086 		.asc = 0x10,
3087 		.ascq = 0x01, /* LOGICAL BLOCK GUARD CHECK FAILED */
3088 		.add_sector_info = true,
3089 	},
3090 	[TCM_LOGICAL_BLOCK_APP_TAG_CHECK_FAILED] = {
3091 		.key = ABORTED_COMMAND,
3092 		.asc = 0x10,
3093 		.ascq = 0x02, /* LOGICAL BLOCK APPLICATION TAG CHECK FAILED */
3094 		.add_sector_info = true,
3095 	},
3096 	[TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED] = {
3097 		.key = ABORTED_COMMAND,
3098 		.asc = 0x10,
3099 		.ascq = 0x03, /* LOGICAL BLOCK REFERENCE TAG CHECK FAILED */
3100 		.add_sector_info = true,
3101 	},
3102 	[TCM_COPY_TARGET_DEVICE_NOT_REACHABLE] = {
3103 		.key = COPY_ABORTED,
3104 		.asc = 0x0d,
3105 		.ascq = 0x02, /* COPY TARGET DEVICE NOT REACHABLE */
3106 
3107 	},
3108 	[TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE] = {
3109 		/*
3110 		 * Returning ILLEGAL REQUEST would cause immediate IO errors on
3111 		 * Solaris initiators.  Returning NOT READY instead means the
3112 		 * operations will be retried a finite number of times and we
3113 		 * can survive intermittent errors.
3114 		 */
3115 		.key = NOT_READY,
3116 		.asc = 0x08, /* LOGICAL UNIT COMMUNICATION FAILURE */
3117 	},
3118 	[TCM_INSUFFICIENT_REGISTRATION_RESOURCES] = {
3119 		/*
3120 		 * From spc4r22 section5.7.7,5.7.8
3121 		 * If a PERSISTENT RESERVE OUT command with a REGISTER service action
3122 		 * or a REGISTER AND IGNORE EXISTING KEY service action or
3123 		 * REGISTER AND MOVE service actionis attempted,
3124 		 * but there are insufficient device server resources to complete the
3125 		 * operation, then the command shall be terminated with CHECK CONDITION
3126 		 * status, with the sense key set to ILLEGAL REQUEST,and the additonal
3127 		 * sense code set to INSUFFICIENT REGISTRATION RESOURCES.
3128 		 */
3129 		.key = ILLEGAL_REQUEST,
3130 		.asc = 0x55,
3131 		.ascq = 0x04, /* INSUFFICIENT REGISTRATION RESOURCES */
3132 	},
3133 };
3134 
3135 static int translate_sense_reason(struct se_cmd *cmd, sense_reason_t reason)
3136 {
3137 	const struct sense_info *si;
3138 	u8 *buffer = cmd->sense_buffer;
3139 	int r = (__force int)reason;
3140 	u8 asc, ascq;
3141 	bool desc_format = target_sense_desc_format(cmd->se_dev);
3142 
3143 	if (r < ARRAY_SIZE(sense_info_table) && sense_info_table[r].key)
3144 		si = &sense_info_table[r];
3145 	else
3146 		si = &sense_info_table[(__force int)
3147 				       TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE];
3148 
3149 	if (reason == TCM_CHECK_CONDITION_UNIT_ATTENTION) {
3150 		core_scsi3_ua_for_check_condition(cmd, &asc, &ascq);
3151 		WARN_ON_ONCE(asc == 0);
3152 	} else if (si->asc == 0) {
3153 		WARN_ON_ONCE(cmd->scsi_asc == 0);
3154 		asc = cmd->scsi_asc;
3155 		ascq = cmd->scsi_ascq;
3156 	} else {
3157 		asc = si->asc;
3158 		ascq = si->ascq;
3159 	}
3160 
3161 	scsi_build_sense_buffer(desc_format, buffer, si->key, asc, ascq);
3162 	if (si->add_sector_info)
3163 		return scsi_set_sense_information(buffer,
3164 						  cmd->scsi_sense_length,
3165 						  cmd->bad_sector);
3166 
3167 	return 0;
3168 }
3169 
3170 int
3171 transport_send_check_condition_and_sense(struct se_cmd *cmd,
3172 		sense_reason_t reason, int from_transport)
3173 {
3174 	unsigned long flags;
3175 
3176 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3177 	if (cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION) {
3178 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3179 		return 0;
3180 	}
3181 	cmd->se_cmd_flags |= SCF_SENT_CHECK_CONDITION;
3182 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3183 
3184 	if (!from_transport) {
3185 		int rc;
3186 
3187 		cmd->se_cmd_flags |= SCF_EMULATED_TASK_SENSE;
3188 		cmd->scsi_status = SAM_STAT_CHECK_CONDITION;
3189 		cmd->scsi_sense_length  = TRANSPORT_SENSE_BUFFER;
3190 		rc = translate_sense_reason(cmd, reason);
3191 		if (rc)
3192 			return rc;
3193 	}
3194 
3195 	trace_target_cmd_complete(cmd);
3196 	return cmd->se_tfo->queue_status(cmd);
3197 }
3198 EXPORT_SYMBOL(transport_send_check_condition_and_sense);
3199 
3200 static int __transport_check_aborted_status(struct se_cmd *cmd, int send_status)
3201 	__releases(&cmd->t_state_lock)
3202 	__acquires(&cmd->t_state_lock)
3203 {
3204 	int ret;
3205 
3206 	assert_spin_locked(&cmd->t_state_lock);
3207 	WARN_ON_ONCE(!irqs_disabled());
3208 
3209 	if (!(cmd->transport_state & CMD_T_ABORTED))
3210 		return 0;
3211 	/*
3212 	 * If cmd has been aborted but either no status is to be sent or it has
3213 	 * already been sent, just return
3214 	 */
3215 	if (!send_status || !(cmd->se_cmd_flags & SCF_SEND_DELAYED_TAS)) {
3216 		if (send_status)
3217 			cmd->se_cmd_flags |= SCF_SEND_DELAYED_TAS;
3218 		return 1;
3219 	}
3220 
3221 	pr_debug("Sending delayed SAM_STAT_TASK_ABORTED status for CDB:"
3222 		" 0x%02x ITT: 0x%08llx\n", cmd->t_task_cdb[0], cmd->tag);
3223 
3224 	cmd->se_cmd_flags &= ~SCF_SEND_DELAYED_TAS;
3225 	cmd->scsi_status = SAM_STAT_TASK_ABORTED;
3226 	trace_target_cmd_complete(cmd);
3227 
3228 	spin_unlock_irq(&cmd->t_state_lock);
3229 	ret = cmd->se_tfo->queue_status(cmd);
3230 	if (ret)
3231 		transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
3232 	spin_lock_irq(&cmd->t_state_lock);
3233 
3234 	return 1;
3235 }
3236 
3237 int transport_check_aborted_status(struct se_cmd *cmd, int send_status)
3238 {
3239 	int ret;
3240 
3241 	spin_lock_irq(&cmd->t_state_lock);
3242 	ret = __transport_check_aborted_status(cmd, send_status);
3243 	spin_unlock_irq(&cmd->t_state_lock);
3244 
3245 	return ret;
3246 }
3247 EXPORT_SYMBOL(transport_check_aborted_status);
3248 
3249 void transport_send_task_abort(struct se_cmd *cmd)
3250 {
3251 	unsigned long flags;
3252 	int ret;
3253 
3254 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3255 	if (cmd->se_cmd_flags & (SCF_SENT_CHECK_CONDITION)) {
3256 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3257 		return;
3258 	}
3259 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3260 
3261 	/*
3262 	 * If there are still expected incoming fabric WRITEs, we wait
3263 	 * until until they have completed before sending a TASK_ABORTED
3264 	 * response.  This response with TASK_ABORTED status will be
3265 	 * queued back to fabric module by transport_check_aborted_status().
3266 	 */
3267 	if (cmd->data_direction == DMA_TO_DEVICE) {
3268 		if (cmd->se_tfo->write_pending_status(cmd) != 0) {
3269 			spin_lock_irqsave(&cmd->t_state_lock, flags);
3270 			if (cmd->se_cmd_flags & SCF_SEND_DELAYED_TAS) {
3271 				spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3272 				goto send_abort;
3273 			}
3274 			cmd->se_cmd_flags |= SCF_SEND_DELAYED_TAS;
3275 			spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3276 			return;
3277 		}
3278 	}
3279 send_abort:
3280 	cmd->scsi_status = SAM_STAT_TASK_ABORTED;
3281 
3282 	transport_lun_remove_cmd(cmd);
3283 
3284 	pr_debug("Setting SAM_STAT_TASK_ABORTED status for CDB: 0x%02x, ITT: 0x%08llx\n",
3285 		 cmd->t_task_cdb[0], cmd->tag);
3286 
3287 	trace_target_cmd_complete(cmd);
3288 	ret = cmd->se_tfo->queue_status(cmd);
3289 	if (ret)
3290 		transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
3291 }
3292 
3293 static void target_tmr_work(struct work_struct *work)
3294 {
3295 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
3296 	struct se_device *dev = cmd->se_dev;
3297 	struct se_tmr_req *tmr = cmd->se_tmr_req;
3298 	unsigned long flags;
3299 	int ret;
3300 
3301 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3302 	if (cmd->transport_state & CMD_T_ABORTED) {
3303 		tmr->response = TMR_FUNCTION_REJECTED;
3304 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3305 		goto check_stop;
3306 	}
3307 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3308 
3309 	switch (tmr->function) {
3310 	case TMR_ABORT_TASK:
3311 		core_tmr_abort_task(dev, tmr, cmd->se_sess);
3312 		break;
3313 	case TMR_ABORT_TASK_SET:
3314 	case TMR_CLEAR_ACA:
3315 	case TMR_CLEAR_TASK_SET:
3316 		tmr->response = TMR_TASK_MGMT_FUNCTION_NOT_SUPPORTED;
3317 		break;
3318 	case TMR_LUN_RESET:
3319 		ret = core_tmr_lun_reset(dev, tmr, NULL, NULL);
3320 		tmr->response = (!ret) ? TMR_FUNCTION_COMPLETE :
3321 					 TMR_FUNCTION_REJECTED;
3322 		if (tmr->response == TMR_FUNCTION_COMPLETE) {
3323 			target_ua_allocate_lun(cmd->se_sess->se_node_acl,
3324 					       cmd->orig_fe_lun, 0x29,
3325 					       ASCQ_29H_BUS_DEVICE_RESET_FUNCTION_OCCURRED);
3326 		}
3327 		break;
3328 	case TMR_TARGET_WARM_RESET:
3329 		tmr->response = TMR_FUNCTION_REJECTED;
3330 		break;
3331 	case TMR_TARGET_COLD_RESET:
3332 		tmr->response = TMR_FUNCTION_REJECTED;
3333 		break;
3334 	default:
3335 		pr_err("Uknown TMR function: 0x%02x.\n",
3336 				tmr->function);
3337 		tmr->response = TMR_FUNCTION_REJECTED;
3338 		break;
3339 	}
3340 
3341 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3342 	if (cmd->transport_state & CMD_T_ABORTED) {
3343 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3344 		goto check_stop;
3345 	}
3346 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3347 
3348 	cmd->se_tfo->queue_tm_rsp(cmd);
3349 
3350 check_stop:
3351 	transport_lun_remove_cmd(cmd);
3352 	transport_cmd_check_stop_to_fabric(cmd);
3353 }
3354 
3355 int transport_generic_handle_tmr(
3356 	struct se_cmd *cmd)
3357 {
3358 	unsigned long flags;
3359 	bool aborted = false;
3360 
3361 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3362 	if (cmd->transport_state & CMD_T_ABORTED) {
3363 		aborted = true;
3364 	} else {
3365 		cmd->t_state = TRANSPORT_ISTATE_PROCESSING;
3366 		cmd->transport_state |= CMD_T_ACTIVE;
3367 	}
3368 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3369 
3370 	if (aborted) {
3371 		pr_warn_ratelimited("handle_tmr caught CMD_T_ABORTED TMR %d"
3372 			"ref_tag: %llu tag: %llu\n", cmd->se_tmr_req->function,
3373 			cmd->se_tmr_req->ref_task_tag, cmd->tag);
3374 		transport_lun_remove_cmd(cmd);
3375 		transport_cmd_check_stop_to_fabric(cmd);
3376 		return 0;
3377 	}
3378 
3379 	INIT_WORK(&cmd->work, target_tmr_work);
3380 	queue_work(cmd->se_dev->tmr_wq, &cmd->work);
3381 	return 0;
3382 }
3383 EXPORT_SYMBOL(transport_generic_handle_tmr);
3384 
3385 bool
3386 target_check_wce(struct se_device *dev)
3387 {
3388 	bool wce = false;
3389 
3390 	if (dev->transport->get_write_cache)
3391 		wce = dev->transport->get_write_cache(dev);
3392 	else if (dev->dev_attrib.emulate_write_cache > 0)
3393 		wce = true;
3394 
3395 	return wce;
3396 }
3397 
3398 bool
3399 target_check_fua(struct se_device *dev)
3400 {
3401 	return target_check_wce(dev) && dev->dev_attrib.emulate_fua_write > 0;
3402 }
3403