xref: /openbmc/linux/drivers/target/target_core_transport.c (revision b24413180f5600bcb3bb70fbed5cf186b60864bd)
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 int transport_put_cmd(struct se_cmd *cmd);
71 static void target_complete_ok_work(struct work_struct *work);
72 
73 int init_se_kmem_caches(void)
74 {
75 	se_sess_cache = kmem_cache_create("se_sess_cache",
76 			sizeof(struct se_session), __alignof__(struct se_session),
77 			0, NULL);
78 	if (!se_sess_cache) {
79 		pr_err("kmem_cache_create() for struct se_session"
80 				" failed\n");
81 		goto out;
82 	}
83 	se_ua_cache = kmem_cache_create("se_ua_cache",
84 			sizeof(struct se_ua), __alignof__(struct se_ua),
85 			0, NULL);
86 	if (!se_ua_cache) {
87 		pr_err("kmem_cache_create() for struct se_ua failed\n");
88 		goto out_free_sess_cache;
89 	}
90 	t10_pr_reg_cache = kmem_cache_create("t10_pr_reg_cache",
91 			sizeof(struct t10_pr_registration),
92 			__alignof__(struct t10_pr_registration), 0, NULL);
93 	if (!t10_pr_reg_cache) {
94 		pr_err("kmem_cache_create() for struct t10_pr_registration"
95 				" failed\n");
96 		goto out_free_ua_cache;
97 	}
98 	t10_alua_lu_gp_cache = kmem_cache_create("t10_alua_lu_gp_cache",
99 			sizeof(struct t10_alua_lu_gp), __alignof__(struct t10_alua_lu_gp),
100 			0, NULL);
101 	if (!t10_alua_lu_gp_cache) {
102 		pr_err("kmem_cache_create() for t10_alua_lu_gp_cache"
103 				" failed\n");
104 		goto out_free_pr_reg_cache;
105 	}
106 	t10_alua_lu_gp_mem_cache = kmem_cache_create("t10_alua_lu_gp_mem_cache",
107 			sizeof(struct t10_alua_lu_gp_member),
108 			__alignof__(struct t10_alua_lu_gp_member), 0, NULL);
109 	if (!t10_alua_lu_gp_mem_cache) {
110 		pr_err("kmem_cache_create() for t10_alua_lu_gp_mem_"
111 				"cache failed\n");
112 		goto out_free_lu_gp_cache;
113 	}
114 	t10_alua_tg_pt_gp_cache = kmem_cache_create("t10_alua_tg_pt_gp_cache",
115 			sizeof(struct t10_alua_tg_pt_gp),
116 			__alignof__(struct t10_alua_tg_pt_gp), 0, NULL);
117 	if (!t10_alua_tg_pt_gp_cache) {
118 		pr_err("kmem_cache_create() for t10_alua_tg_pt_gp_"
119 				"cache failed\n");
120 		goto out_free_lu_gp_mem_cache;
121 	}
122 	t10_alua_lba_map_cache = kmem_cache_create(
123 			"t10_alua_lba_map_cache",
124 			sizeof(struct t10_alua_lba_map),
125 			__alignof__(struct t10_alua_lba_map), 0, NULL);
126 	if (!t10_alua_lba_map_cache) {
127 		pr_err("kmem_cache_create() for t10_alua_lba_map_"
128 				"cache failed\n");
129 		goto out_free_tg_pt_gp_cache;
130 	}
131 	t10_alua_lba_map_mem_cache = kmem_cache_create(
132 			"t10_alua_lba_map_mem_cache",
133 			sizeof(struct t10_alua_lba_map_member),
134 			__alignof__(struct t10_alua_lba_map_member), 0, NULL);
135 	if (!t10_alua_lba_map_mem_cache) {
136 		pr_err("kmem_cache_create() for t10_alua_lba_map_mem_"
137 				"cache failed\n");
138 		goto out_free_lba_map_cache;
139 	}
140 
141 	target_completion_wq = alloc_workqueue("target_completion",
142 					       WQ_MEM_RECLAIM, 0);
143 	if (!target_completion_wq)
144 		goto out_free_lba_map_mem_cache;
145 
146 	return 0;
147 
148 out_free_lba_map_mem_cache:
149 	kmem_cache_destroy(t10_alua_lba_map_mem_cache);
150 out_free_lba_map_cache:
151 	kmem_cache_destroy(t10_alua_lba_map_cache);
152 out_free_tg_pt_gp_cache:
153 	kmem_cache_destroy(t10_alua_tg_pt_gp_cache);
154 out_free_lu_gp_mem_cache:
155 	kmem_cache_destroy(t10_alua_lu_gp_mem_cache);
156 out_free_lu_gp_cache:
157 	kmem_cache_destroy(t10_alua_lu_gp_cache);
158 out_free_pr_reg_cache:
159 	kmem_cache_destroy(t10_pr_reg_cache);
160 out_free_ua_cache:
161 	kmem_cache_destroy(se_ua_cache);
162 out_free_sess_cache:
163 	kmem_cache_destroy(se_sess_cache);
164 out:
165 	return -ENOMEM;
166 }
167 
168 void release_se_kmem_caches(void)
169 {
170 	destroy_workqueue(target_completion_wq);
171 	kmem_cache_destroy(se_sess_cache);
172 	kmem_cache_destroy(se_ua_cache);
173 	kmem_cache_destroy(t10_pr_reg_cache);
174 	kmem_cache_destroy(t10_alua_lu_gp_cache);
175 	kmem_cache_destroy(t10_alua_lu_gp_mem_cache);
176 	kmem_cache_destroy(t10_alua_tg_pt_gp_cache);
177 	kmem_cache_destroy(t10_alua_lba_map_cache);
178 	kmem_cache_destroy(t10_alua_lba_map_mem_cache);
179 }
180 
181 /* This code ensures unique mib indexes are handed out. */
182 static DEFINE_SPINLOCK(scsi_mib_index_lock);
183 static u32 scsi_mib_index[SCSI_INDEX_TYPE_MAX];
184 
185 /*
186  * Allocate a new row index for the entry type specified
187  */
188 u32 scsi_get_new_index(scsi_index_t type)
189 {
190 	u32 new_index;
191 
192 	BUG_ON((type < 0) || (type >= SCSI_INDEX_TYPE_MAX));
193 
194 	spin_lock(&scsi_mib_index_lock);
195 	new_index = ++scsi_mib_index[type];
196 	spin_unlock(&scsi_mib_index_lock);
197 
198 	return new_index;
199 }
200 
201 void transport_subsystem_check_init(void)
202 {
203 	int ret;
204 	static int sub_api_initialized;
205 
206 	if (sub_api_initialized)
207 		return;
208 
209 	ret = request_module("target_core_iblock");
210 	if (ret != 0)
211 		pr_err("Unable to load target_core_iblock\n");
212 
213 	ret = request_module("target_core_file");
214 	if (ret != 0)
215 		pr_err("Unable to load target_core_file\n");
216 
217 	ret = request_module("target_core_pscsi");
218 	if (ret != 0)
219 		pr_err("Unable to load target_core_pscsi\n");
220 
221 	ret = request_module("target_core_user");
222 	if (ret != 0)
223 		pr_err("Unable to load target_core_user\n");
224 
225 	sub_api_initialized = 1;
226 }
227 
228 struct se_session *transport_init_session(enum target_prot_op sup_prot_ops)
229 {
230 	struct se_session *se_sess;
231 
232 	se_sess = kmem_cache_zalloc(se_sess_cache, GFP_KERNEL);
233 	if (!se_sess) {
234 		pr_err("Unable to allocate struct se_session from"
235 				" se_sess_cache\n");
236 		return ERR_PTR(-ENOMEM);
237 	}
238 	INIT_LIST_HEAD(&se_sess->sess_list);
239 	INIT_LIST_HEAD(&se_sess->sess_acl_list);
240 	INIT_LIST_HEAD(&se_sess->sess_cmd_list);
241 	INIT_LIST_HEAD(&se_sess->sess_wait_list);
242 	spin_lock_init(&se_sess->sess_cmd_lock);
243 	se_sess->sup_prot_ops = sup_prot_ops;
244 
245 	return se_sess;
246 }
247 EXPORT_SYMBOL(transport_init_session);
248 
249 int transport_alloc_session_tags(struct se_session *se_sess,
250 			         unsigned int tag_num, unsigned int tag_size)
251 {
252 	int rc;
253 
254 	se_sess->sess_cmd_map = kzalloc(tag_num * tag_size,
255 					GFP_KERNEL | __GFP_NOWARN | __GFP_RETRY_MAYFAIL);
256 	if (!se_sess->sess_cmd_map) {
257 		se_sess->sess_cmd_map = vzalloc(tag_num * tag_size);
258 		if (!se_sess->sess_cmd_map) {
259 			pr_err("Unable to allocate se_sess->sess_cmd_map\n");
260 			return -ENOMEM;
261 		}
262 	}
263 
264 	rc = percpu_ida_init(&se_sess->sess_tag_pool, tag_num);
265 	if (rc < 0) {
266 		pr_err("Unable to init se_sess->sess_tag_pool,"
267 			" tag_num: %u\n", tag_num);
268 		kvfree(se_sess->sess_cmd_map);
269 		se_sess->sess_cmd_map = NULL;
270 		return -ENOMEM;
271 	}
272 
273 	return 0;
274 }
275 EXPORT_SYMBOL(transport_alloc_session_tags);
276 
277 struct se_session *transport_init_session_tags(unsigned int tag_num,
278 					       unsigned int tag_size,
279 					       enum target_prot_op sup_prot_ops)
280 {
281 	struct se_session *se_sess;
282 	int rc;
283 
284 	if (tag_num != 0 && !tag_size) {
285 		pr_err("init_session_tags called with percpu-ida tag_num:"
286 		       " %u, but zero tag_size\n", tag_num);
287 		return ERR_PTR(-EINVAL);
288 	}
289 	if (!tag_num && tag_size) {
290 		pr_err("init_session_tags called with percpu-ida tag_size:"
291 		       " %u, but zero tag_num\n", tag_size);
292 		return ERR_PTR(-EINVAL);
293 	}
294 
295 	se_sess = transport_init_session(sup_prot_ops);
296 	if (IS_ERR(se_sess))
297 		return se_sess;
298 
299 	rc = transport_alloc_session_tags(se_sess, tag_num, tag_size);
300 	if (rc < 0) {
301 		transport_free_session(se_sess);
302 		return ERR_PTR(-ENOMEM);
303 	}
304 
305 	return se_sess;
306 }
307 EXPORT_SYMBOL(transport_init_session_tags);
308 
309 /*
310  * Called with spin_lock_irqsave(&struct se_portal_group->session_lock called.
311  */
312 void __transport_register_session(
313 	struct se_portal_group *se_tpg,
314 	struct se_node_acl *se_nacl,
315 	struct se_session *se_sess,
316 	void *fabric_sess_ptr)
317 {
318 	const struct target_core_fabric_ops *tfo = se_tpg->se_tpg_tfo;
319 	unsigned char buf[PR_REG_ISID_LEN];
320 
321 	se_sess->se_tpg = se_tpg;
322 	se_sess->fabric_sess_ptr = fabric_sess_ptr;
323 	/*
324 	 * Used by struct se_node_acl's under ConfigFS to locate active se_session-t
325 	 *
326 	 * Only set for struct se_session's that will actually be moving I/O.
327 	 * eg: *NOT* discovery sessions.
328 	 */
329 	if (se_nacl) {
330 		/*
331 		 *
332 		 * Determine if fabric allows for T10-PI feature bits exposed to
333 		 * initiators for device backends with !dev->dev_attrib.pi_prot_type.
334 		 *
335 		 * If so, then always save prot_type on a per se_node_acl node
336 		 * basis and re-instate the previous sess_prot_type to avoid
337 		 * disabling PI from below any previously initiator side
338 		 * registered LUNs.
339 		 */
340 		if (se_nacl->saved_prot_type)
341 			se_sess->sess_prot_type = se_nacl->saved_prot_type;
342 		else if (tfo->tpg_check_prot_fabric_only)
343 			se_sess->sess_prot_type = se_nacl->saved_prot_type =
344 					tfo->tpg_check_prot_fabric_only(se_tpg);
345 		/*
346 		 * If the fabric module supports an ISID based TransportID,
347 		 * save this value in binary from the fabric I_T Nexus now.
348 		 */
349 		if (se_tpg->se_tpg_tfo->sess_get_initiator_sid != NULL) {
350 			memset(&buf[0], 0, PR_REG_ISID_LEN);
351 			se_tpg->se_tpg_tfo->sess_get_initiator_sid(se_sess,
352 					&buf[0], PR_REG_ISID_LEN);
353 			se_sess->sess_bin_isid = get_unaligned_be64(&buf[0]);
354 		}
355 
356 		spin_lock_irq(&se_nacl->nacl_sess_lock);
357 		/*
358 		 * The se_nacl->nacl_sess pointer will be set to the
359 		 * last active I_T Nexus for each struct se_node_acl.
360 		 */
361 		se_nacl->nacl_sess = se_sess;
362 
363 		list_add_tail(&se_sess->sess_acl_list,
364 			      &se_nacl->acl_sess_list);
365 		spin_unlock_irq(&se_nacl->nacl_sess_lock);
366 	}
367 	list_add_tail(&se_sess->sess_list, &se_tpg->tpg_sess_list);
368 
369 	pr_debug("TARGET_CORE[%s]: Registered fabric_sess_ptr: %p\n",
370 		se_tpg->se_tpg_tfo->get_fabric_name(), se_sess->fabric_sess_ptr);
371 }
372 EXPORT_SYMBOL(__transport_register_session);
373 
374 void transport_register_session(
375 	struct se_portal_group *se_tpg,
376 	struct se_node_acl *se_nacl,
377 	struct se_session *se_sess,
378 	void *fabric_sess_ptr)
379 {
380 	unsigned long flags;
381 
382 	spin_lock_irqsave(&se_tpg->session_lock, flags);
383 	__transport_register_session(se_tpg, se_nacl, se_sess, fabric_sess_ptr);
384 	spin_unlock_irqrestore(&se_tpg->session_lock, flags);
385 }
386 EXPORT_SYMBOL(transport_register_session);
387 
388 struct se_session *
389 target_alloc_session(struct se_portal_group *tpg,
390 		     unsigned int tag_num, unsigned int tag_size,
391 		     enum target_prot_op prot_op,
392 		     const char *initiatorname, void *private,
393 		     int (*callback)(struct se_portal_group *,
394 				     struct se_session *, void *))
395 {
396 	struct se_session *sess;
397 
398 	/*
399 	 * If the fabric driver is using percpu-ida based pre allocation
400 	 * of I/O descriptor tags, go ahead and perform that setup now..
401 	 */
402 	if (tag_num != 0)
403 		sess = transport_init_session_tags(tag_num, tag_size, prot_op);
404 	else
405 		sess = transport_init_session(prot_op);
406 
407 	if (IS_ERR(sess))
408 		return sess;
409 
410 	sess->se_node_acl = core_tpg_check_initiator_node_acl(tpg,
411 					(unsigned char *)initiatorname);
412 	if (!sess->se_node_acl) {
413 		transport_free_session(sess);
414 		return ERR_PTR(-EACCES);
415 	}
416 	/*
417 	 * Go ahead and perform any remaining fabric setup that is
418 	 * required before transport_register_session().
419 	 */
420 	if (callback != NULL) {
421 		int rc = callback(tpg, sess, private);
422 		if (rc) {
423 			transport_free_session(sess);
424 			return ERR_PTR(rc);
425 		}
426 	}
427 
428 	transport_register_session(tpg, sess->se_node_acl, sess, private);
429 	return sess;
430 }
431 EXPORT_SYMBOL(target_alloc_session);
432 
433 ssize_t target_show_dynamic_sessions(struct se_portal_group *se_tpg, char *page)
434 {
435 	struct se_session *se_sess;
436 	ssize_t len = 0;
437 
438 	spin_lock_bh(&se_tpg->session_lock);
439 	list_for_each_entry(se_sess, &se_tpg->tpg_sess_list, sess_list) {
440 		if (!se_sess->se_node_acl)
441 			continue;
442 		if (!se_sess->se_node_acl->dynamic_node_acl)
443 			continue;
444 		if (strlen(se_sess->se_node_acl->initiatorname) + 1 + len > PAGE_SIZE)
445 			break;
446 
447 		len += snprintf(page + len, PAGE_SIZE - len, "%s\n",
448 				se_sess->se_node_acl->initiatorname);
449 		len += 1; /* Include NULL terminator */
450 	}
451 	spin_unlock_bh(&se_tpg->session_lock);
452 
453 	return len;
454 }
455 EXPORT_SYMBOL(target_show_dynamic_sessions);
456 
457 static void target_complete_nacl(struct kref *kref)
458 {
459 	struct se_node_acl *nacl = container_of(kref,
460 				struct se_node_acl, acl_kref);
461 	struct se_portal_group *se_tpg = nacl->se_tpg;
462 
463 	if (!nacl->dynamic_stop) {
464 		complete(&nacl->acl_free_comp);
465 		return;
466 	}
467 
468 	mutex_lock(&se_tpg->acl_node_mutex);
469 	list_del_init(&nacl->acl_list);
470 	mutex_unlock(&se_tpg->acl_node_mutex);
471 
472 	core_tpg_wait_for_nacl_pr_ref(nacl);
473 	core_free_device_list_for_node(nacl, se_tpg);
474 	kfree(nacl);
475 }
476 
477 void target_put_nacl(struct se_node_acl *nacl)
478 {
479 	kref_put(&nacl->acl_kref, target_complete_nacl);
480 }
481 EXPORT_SYMBOL(target_put_nacl);
482 
483 void transport_deregister_session_configfs(struct se_session *se_sess)
484 {
485 	struct se_node_acl *se_nacl;
486 	unsigned long flags;
487 	/*
488 	 * Used by struct se_node_acl's under ConfigFS to locate active struct se_session
489 	 */
490 	se_nacl = se_sess->se_node_acl;
491 	if (se_nacl) {
492 		spin_lock_irqsave(&se_nacl->nacl_sess_lock, flags);
493 		if (!list_empty(&se_sess->sess_acl_list))
494 			list_del_init(&se_sess->sess_acl_list);
495 		/*
496 		 * If the session list is empty, then clear the pointer.
497 		 * Otherwise, set the struct se_session pointer from the tail
498 		 * element of the per struct se_node_acl active session list.
499 		 */
500 		if (list_empty(&se_nacl->acl_sess_list))
501 			se_nacl->nacl_sess = NULL;
502 		else {
503 			se_nacl->nacl_sess = container_of(
504 					se_nacl->acl_sess_list.prev,
505 					struct se_session, sess_acl_list);
506 		}
507 		spin_unlock_irqrestore(&se_nacl->nacl_sess_lock, flags);
508 	}
509 }
510 EXPORT_SYMBOL(transport_deregister_session_configfs);
511 
512 void transport_free_session(struct se_session *se_sess)
513 {
514 	struct se_node_acl *se_nacl = se_sess->se_node_acl;
515 
516 	/*
517 	 * Drop the se_node_acl->nacl_kref obtained from within
518 	 * core_tpg_get_initiator_node_acl().
519 	 */
520 	if (se_nacl) {
521 		struct se_portal_group *se_tpg = se_nacl->se_tpg;
522 		const struct target_core_fabric_ops *se_tfo = se_tpg->se_tpg_tfo;
523 		unsigned long flags;
524 
525 		se_sess->se_node_acl = NULL;
526 
527 		/*
528 		 * Also determine if we need to drop the extra ->cmd_kref if
529 		 * it had been previously dynamically generated, and
530 		 * the endpoint is not caching dynamic ACLs.
531 		 */
532 		mutex_lock(&se_tpg->acl_node_mutex);
533 		if (se_nacl->dynamic_node_acl &&
534 		    !se_tfo->tpg_check_demo_mode_cache(se_tpg)) {
535 			spin_lock_irqsave(&se_nacl->nacl_sess_lock, flags);
536 			if (list_empty(&se_nacl->acl_sess_list))
537 				se_nacl->dynamic_stop = true;
538 			spin_unlock_irqrestore(&se_nacl->nacl_sess_lock, flags);
539 
540 			if (se_nacl->dynamic_stop)
541 				list_del_init(&se_nacl->acl_list);
542 		}
543 		mutex_unlock(&se_tpg->acl_node_mutex);
544 
545 		if (se_nacl->dynamic_stop)
546 			target_put_nacl(se_nacl);
547 
548 		target_put_nacl(se_nacl);
549 	}
550 	if (se_sess->sess_cmd_map) {
551 		percpu_ida_destroy(&se_sess->sess_tag_pool);
552 		kvfree(se_sess->sess_cmd_map);
553 	}
554 	kmem_cache_free(se_sess_cache, se_sess);
555 }
556 EXPORT_SYMBOL(transport_free_session);
557 
558 void transport_deregister_session(struct se_session *se_sess)
559 {
560 	struct se_portal_group *se_tpg = se_sess->se_tpg;
561 	unsigned long flags;
562 
563 	if (!se_tpg) {
564 		transport_free_session(se_sess);
565 		return;
566 	}
567 
568 	spin_lock_irqsave(&se_tpg->session_lock, flags);
569 	list_del(&se_sess->sess_list);
570 	se_sess->se_tpg = NULL;
571 	se_sess->fabric_sess_ptr = NULL;
572 	spin_unlock_irqrestore(&se_tpg->session_lock, flags);
573 
574 	pr_debug("TARGET_CORE[%s]: Deregistered fabric_sess\n",
575 		se_tpg->se_tpg_tfo->get_fabric_name());
576 	/*
577 	 * If last kref is dropping now for an explicit NodeACL, awake sleeping
578 	 * ->acl_free_comp caller to wakeup configfs se_node_acl->acl_group
579 	 * removal context from within transport_free_session() code.
580 	 *
581 	 * For dynamic ACL, target_put_nacl() uses target_complete_nacl()
582 	 * to release all remaining generate_node_acl=1 created ACL resources.
583 	 */
584 
585 	transport_free_session(se_sess);
586 }
587 EXPORT_SYMBOL(transport_deregister_session);
588 
589 static void target_remove_from_state_list(struct se_cmd *cmd)
590 {
591 	struct se_device *dev = cmd->se_dev;
592 	unsigned long flags;
593 
594 	if (!dev)
595 		return;
596 
597 	spin_lock_irqsave(&dev->execute_task_lock, flags);
598 	if (cmd->state_active) {
599 		list_del(&cmd->state_list);
600 		cmd->state_active = false;
601 	}
602 	spin_unlock_irqrestore(&dev->execute_task_lock, flags);
603 }
604 
605 static int transport_cmd_check_stop_to_fabric(struct se_cmd *cmd)
606 {
607 	unsigned long flags;
608 
609 	target_remove_from_state_list(cmd);
610 
611 	/*
612 	 * Clear struct se_cmd->se_lun before the handoff to FE.
613 	 */
614 	cmd->se_lun = NULL;
615 
616 	spin_lock_irqsave(&cmd->t_state_lock, flags);
617 	/*
618 	 * Determine if frontend context caller is requesting the stopping of
619 	 * this command for frontend exceptions.
620 	 */
621 	if (cmd->transport_state & CMD_T_STOP) {
622 		pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08llx\n",
623 			__func__, __LINE__, cmd->tag);
624 
625 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
626 
627 		complete_all(&cmd->t_transport_stop_comp);
628 		return 1;
629 	}
630 	cmd->transport_state &= ~CMD_T_ACTIVE;
631 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
632 
633 	/*
634 	 * Some fabric modules like tcm_loop can release their internally
635 	 * allocated I/O reference and struct se_cmd now.
636 	 *
637 	 * Fabric modules are expected to return '1' here if the se_cmd being
638 	 * passed is released at this point, or zero if not being released.
639 	 */
640 	return cmd->se_tfo->check_stop_free(cmd);
641 }
642 
643 static void transport_lun_remove_cmd(struct se_cmd *cmd)
644 {
645 	struct se_lun *lun = cmd->se_lun;
646 
647 	if (!lun)
648 		return;
649 
650 	if (cmpxchg(&cmd->lun_ref_active, true, false))
651 		percpu_ref_put(&lun->lun_ref);
652 }
653 
654 int transport_cmd_finish_abort(struct se_cmd *cmd, int remove)
655 {
656 	bool ack_kref = (cmd->se_cmd_flags & SCF_ACK_KREF);
657 	int ret = 0;
658 
659 	if (cmd->se_cmd_flags & SCF_SE_LUN_CMD)
660 		transport_lun_remove_cmd(cmd);
661 	/*
662 	 * Allow the fabric driver to unmap any resources before
663 	 * releasing the descriptor via TFO->release_cmd()
664 	 */
665 	if (remove)
666 		cmd->se_tfo->aborted_task(cmd);
667 
668 	if (transport_cmd_check_stop_to_fabric(cmd))
669 		return 1;
670 	if (remove && ack_kref)
671 		ret = transport_put_cmd(cmd);
672 
673 	return ret;
674 }
675 
676 static void target_complete_failure_work(struct work_struct *work)
677 {
678 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
679 
680 	transport_generic_request_failure(cmd,
681 			TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE);
682 }
683 
684 /*
685  * Used when asking transport to copy Sense Data from the underlying
686  * Linux/SCSI struct scsi_cmnd
687  */
688 static unsigned char *transport_get_sense_buffer(struct se_cmd *cmd)
689 {
690 	struct se_device *dev = cmd->se_dev;
691 
692 	WARN_ON(!cmd->se_lun);
693 
694 	if (!dev)
695 		return NULL;
696 
697 	if (cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION)
698 		return NULL;
699 
700 	cmd->scsi_sense_length = TRANSPORT_SENSE_BUFFER;
701 
702 	pr_debug("HBA_[%u]_PLUG[%s]: Requesting sense for SAM STATUS: 0x%02x\n",
703 		dev->se_hba->hba_id, dev->transport->name, cmd->scsi_status);
704 	return cmd->sense_buffer;
705 }
706 
707 void transport_copy_sense_to_cmd(struct se_cmd *cmd, unsigned char *sense)
708 {
709 	unsigned char *cmd_sense_buf;
710 	unsigned long flags;
711 
712 	spin_lock_irqsave(&cmd->t_state_lock, flags);
713 	cmd_sense_buf = transport_get_sense_buffer(cmd);
714 	if (!cmd_sense_buf) {
715 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
716 		return;
717 	}
718 
719 	cmd->se_cmd_flags |= SCF_TRANSPORT_TASK_SENSE;
720 	memcpy(cmd_sense_buf, sense, cmd->scsi_sense_length);
721 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
722 }
723 EXPORT_SYMBOL(transport_copy_sense_to_cmd);
724 
725 void target_complete_cmd(struct se_cmd *cmd, u8 scsi_status)
726 {
727 	struct se_device *dev = cmd->se_dev;
728 	int success;
729 	unsigned long flags;
730 
731 	cmd->scsi_status = scsi_status;
732 
733 	spin_lock_irqsave(&cmd->t_state_lock, flags);
734 	switch (cmd->scsi_status) {
735 	case SAM_STAT_CHECK_CONDITION:
736 		if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE)
737 			success = 1;
738 		else
739 			success = 0;
740 		break;
741 	default:
742 		success = 1;
743 		break;
744 	}
745 
746 	/*
747 	 * Check for case where an explicit ABORT_TASK has been received
748 	 * and transport_wait_for_tasks() will be waiting for completion..
749 	 */
750 	if (cmd->transport_state & CMD_T_ABORTED ||
751 	    cmd->transport_state & CMD_T_STOP) {
752 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
753 		/*
754 		 * If COMPARE_AND_WRITE was stopped by __transport_wait_for_tasks(),
755 		 * release se_device->caw_sem obtained by sbc_compare_and_write()
756 		 * since target_complete_ok_work() or target_complete_failure_work()
757 		 * won't be called to invoke the normal CAW completion callbacks.
758 		 */
759 		if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) {
760 			up(&dev->caw_sem);
761 		}
762 		complete_all(&cmd->t_transport_stop_comp);
763 		return;
764 	} else if (!success) {
765 		INIT_WORK(&cmd->work, target_complete_failure_work);
766 	} else {
767 		INIT_WORK(&cmd->work, target_complete_ok_work);
768 	}
769 
770 	cmd->t_state = TRANSPORT_COMPLETE;
771 	cmd->transport_state |= (CMD_T_COMPLETE | CMD_T_ACTIVE);
772 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
773 
774 	if (cmd->se_cmd_flags & SCF_USE_CPUID)
775 		queue_work_on(cmd->cpuid, target_completion_wq, &cmd->work);
776 	else
777 		queue_work(target_completion_wq, &cmd->work);
778 }
779 EXPORT_SYMBOL(target_complete_cmd);
780 
781 void target_complete_cmd_with_length(struct se_cmd *cmd, u8 scsi_status, int length)
782 {
783 	if (scsi_status == SAM_STAT_GOOD && length < cmd->data_length) {
784 		if (cmd->se_cmd_flags & SCF_UNDERFLOW_BIT) {
785 			cmd->residual_count += cmd->data_length - length;
786 		} else {
787 			cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
788 			cmd->residual_count = cmd->data_length - length;
789 		}
790 
791 		cmd->data_length = length;
792 	}
793 
794 	target_complete_cmd(cmd, scsi_status);
795 }
796 EXPORT_SYMBOL(target_complete_cmd_with_length);
797 
798 static void target_add_to_state_list(struct se_cmd *cmd)
799 {
800 	struct se_device *dev = cmd->se_dev;
801 	unsigned long flags;
802 
803 	spin_lock_irqsave(&dev->execute_task_lock, flags);
804 	if (!cmd->state_active) {
805 		list_add_tail(&cmd->state_list, &dev->state_list);
806 		cmd->state_active = true;
807 	}
808 	spin_unlock_irqrestore(&dev->execute_task_lock, flags);
809 }
810 
811 /*
812  * Handle QUEUE_FULL / -EAGAIN and -ENOMEM status
813  */
814 static void transport_write_pending_qf(struct se_cmd *cmd);
815 static void transport_complete_qf(struct se_cmd *cmd);
816 
817 void target_qf_do_work(struct work_struct *work)
818 {
819 	struct se_device *dev = container_of(work, struct se_device,
820 					qf_work_queue);
821 	LIST_HEAD(qf_cmd_list);
822 	struct se_cmd *cmd, *cmd_tmp;
823 
824 	spin_lock_irq(&dev->qf_cmd_lock);
825 	list_splice_init(&dev->qf_cmd_list, &qf_cmd_list);
826 	spin_unlock_irq(&dev->qf_cmd_lock);
827 
828 	list_for_each_entry_safe(cmd, cmd_tmp, &qf_cmd_list, se_qf_node) {
829 		list_del(&cmd->se_qf_node);
830 		atomic_dec_mb(&dev->dev_qf_count);
831 
832 		pr_debug("Processing %s cmd: %p QUEUE_FULL in work queue"
833 			" context: %s\n", cmd->se_tfo->get_fabric_name(), cmd,
834 			(cmd->t_state == TRANSPORT_COMPLETE_QF_OK) ? "COMPLETE_OK" :
835 			(cmd->t_state == TRANSPORT_COMPLETE_QF_WP) ? "WRITE_PENDING"
836 			: "UNKNOWN");
837 
838 		if (cmd->t_state == TRANSPORT_COMPLETE_QF_WP)
839 			transport_write_pending_qf(cmd);
840 		else if (cmd->t_state == TRANSPORT_COMPLETE_QF_OK ||
841 			 cmd->t_state == TRANSPORT_COMPLETE_QF_ERR)
842 			transport_complete_qf(cmd);
843 	}
844 }
845 
846 unsigned char *transport_dump_cmd_direction(struct se_cmd *cmd)
847 {
848 	switch (cmd->data_direction) {
849 	case DMA_NONE:
850 		return "NONE";
851 	case DMA_FROM_DEVICE:
852 		return "READ";
853 	case DMA_TO_DEVICE:
854 		return "WRITE";
855 	case DMA_BIDIRECTIONAL:
856 		return "BIDI";
857 	default:
858 		break;
859 	}
860 
861 	return "UNKNOWN";
862 }
863 
864 void transport_dump_dev_state(
865 	struct se_device *dev,
866 	char *b,
867 	int *bl)
868 {
869 	*bl += sprintf(b + *bl, "Status: ");
870 	if (dev->export_count)
871 		*bl += sprintf(b + *bl, "ACTIVATED");
872 	else
873 		*bl += sprintf(b + *bl, "DEACTIVATED");
874 
875 	*bl += sprintf(b + *bl, "  Max Queue Depth: %d", dev->queue_depth);
876 	*bl += sprintf(b + *bl, "  SectorSize: %u  HwMaxSectors: %u\n",
877 		dev->dev_attrib.block_size,
878 		dev->dev_attrib.hw_max_sectors);
879 	*bl += sprintf(b + *bl, "        ");
880 }
881 
882 void transport_dump_vpd_proto_id(
883 	struct t10_vpd *vpd,
884 	unsigned char *p_buf,
885 	int p_buf_len)
886 {
887 	unsigned char buf[VPD_TMP_BUF_SIZE];
888 	int len;
889 
890 	memset(buf, 0, VPD_TMP_BUF_SIZE);
891 	len = sprintf(buf, "T10 VPD Protocol Identifier: ");
892 
893 	switch (vpd->protocol_identifier) {
894 	case 0x00:
895 		sprintf(buf+len, "Fibre Channel\n");
896 		break;
897 	case 0x10:
898 		sprintf(buf+len, "Parallel SCSI\n");
899 		break;
900 	case 0x20:
901 		sprintf(buf+len, "SSA\n");
902 		break;
903 	case 0x30:
904 		sprintf(buf+len, "IEEE 1394\n");
905 		break;
906 	case 0x40:
907 		sprintf(buf+len, "SCSI Remote Direct Memory Access"
908 				" Protocol\n");
909 		break;
910 	case 0x50:
911 		sprintf(buf+len, "Internet SCSI (iSCSI)\n");
912 		break;
913 	case 0x60:
914 		sprintf(buf+len, "SAS Serial SCSI Protocol\n");
915 		break;
916 	case 0x70:
917 		sprintf(buf+len, "Automation/Drive Interface Transport"
918 				" Protocol\n");
919 		break;
920 	case 0x80:
921 		sprintf(buf+len, "AT Attachment Interface ATA/ATAPI\n");
922 		break;
923 	default:
924 		sprintf(buf+len, "Unknown 0x%02x\n",
925 				vpd->protocol_identifier);
926 		break;
927 	}
928 
929 	if (p_buf)
930 		strncpy(p_buf, buf, p_buf_len);
931 	else
932 		pr_debug("%s", buf);
933 }
934 
935 void
936 transport_set_vpd_proto_id(struct t10_vpd *vpd, unsigned char *page_83)
937 {
938 	/*
939 	 * Check if the Protocol Identifier Valid (PIV) bit is set..
940 	 *
941 	 * from spc3r23.pdf section 7.5.1
942 	 */
943 	 if (page_83[1] & 0x80) {
944 		vpd->protocol_identifier = (page_83[0] & 0xf0);
945 		vpd->protocol_identifier_set = 1;
946 		transport_dump_vpd_proto_id(vpd, NULL, 0);
947 	}
948 }
949 EXPORT_SYMBOL(transport_set_vpd_proto_id);
950 
951 int transport_dump_vpd_assoc(
952 	struct t10_vpd *vpd,
953 	unsigned char *p_buf,
954 	int p_buf_len)
955 {
956 	unsigned char buf[VPD_TMP_BUF_SIZE];
957 	int ret = 0;
958 	int len;
959 
960 	memset(buf, 0, VPD_TMP_BUF_SIZE);
961 	len = sprintf(buf, "T10 VPD Identifier Association: ");
962 
963 	switch (vpd->association) {
964 	case 0x00:
965 		sprintf(buf+len, "addressed logical unit\n");
966 		break;
967 	case 0x10:
968 		sprintf(buf+len, "target port\n");
969 		break;
970 	case 0x20:
971 		sprintf(buf+len, "SCSI target device\n");
972 		break;
973 	default:
974 		sprintf(buf+len, "Unknown 0x%02x\n", vpd->association);
975 		ret = -EINVAL;
976 		break;
977 	}
978 
979 	if (p_buf)
980 		strncpy(p_buf, buf, p_buf_len);
981 	else
982 		pr_debug("%s", buf);
983 
984 	return ret;
985 }
986 
987 int transport_set_vpd_assoc(struct t10_vpd *vpd, unsigned char *page_83)
988 {
989 	/*
990 	 * The VPD identification association..
991 	 *
992 	 * from spc3r23.pdf Section 7.6.3.1 Table 297
993 	 */
994 	vpd->association = (page_83[1] & 0x30);
995 	return transport_dump_vpd_assoc(vpd, NULL, 0);
996 }
997 EXPORT_SYMBOL(transport_set_vpd_assoc);
998 
999 int transport_dump_vpd_ident_type(
1000 	struct t10_vpd *vpd,
1001 	unsigned char *p_buf,
1002 	int p_buf_len)
1003 {
1004 	unsigned char buf[VPD_TMP_BUF_SIZE];
1005 	int ret = 0;
1006 	int len;
1007 
1008 	memset(buf, 0, VPD_TMP_BUF_SIZE);
1009 	len = sprintf(buf, "T10 VPD Identifier Type: ");
1010 
1011 	switch (vpd->device_identifier_type) {
1012 	case 0x00:
1013 		sprintf(buf+len, "Vendor specific\n");
1014 		break;
1015 	case 0x01:
1016 		sprintf(buf+len, "T10 Vendor ID based\n");
1017 		break;
1018 	case 0x02:
1019 		sprintf(buf+len, "EUI-64 based\n");
1020 		break;
1021 	case 0x03:
1022 		sprintf(buf+len, "NAA\n");
1023 		break;
1024 	case 0x04:
1025 		sprintf(buf+len, "Relative target port identifier\n");
1026 		break;
1027 	case 0x08:
1028 		sprintf(buf+len, "SCSI name string\n");
1029 		break;
1030 	default:
1031 		sprintf(buf+len, "Unsupported: 0x%02x\n",
1032 				vpd->device_identifier_type);
1033 		ret = -EINVAL;
1034 		break;
1035 	}
1036 
1037 	if (p_buf) {
1038 		if (p_buf_len < strlen(buf)+1)
1039 			return -EINVAL;
1040 		strncpy(p_buf, buf, p_buf_len);
1041 	} else {
1042 		pr_debug("%s", buf);
1043 	}
1044 
1045 	return ret;
1046 }
1047 
1048 int transport_set_vpd_ident_type(struct t10_vpd *vpd, unsigned char *page_83)
1049 {
1050 	/*
1051 	 * The VPD identifier type..
1052 	 *
1053 	 * from spc3r23.pdf Section 7.6.3.1 Table 298
1054 	 */
1055 	vpd->device_identifier_type = (page_83[1] & 0x0f);
1056 	return transport_dump_vpd_ident_type(vpd, NULL, 0);
1057 }
1058 EXPORT_SYMBOL(transport_set_vpd_ident_type);
1059 
1060 int transport_dump_vpd_ident(
1061 	struct t10_vpd *vpd,
1062 	unsigned char *p_buf,
1063 	int p_buf_len)
1064 {
1065 	unsigned char buf[VPD_TMP_BUF_SIZE];
1066 	int ret = 0;
1067 
1068 	memset(buf, 0, VPD_TMP_BUF_SIZE);
1069 
1070 	switch (vpd->device_identifier_code_set) {
1071 	case 0x01: /* Binary */
1072 		snprintf(buf, sizeof(buf),
1073 			"T10 VPD Binary Device Identifier: %s\n",
1074 			&vpd->device_identifier[0]);
1075 		break;
1076 	case 0x02: /* ASCII */
1077 		snprintf(buf, sizeof(buf),
1078 			"T10 VPD ASCII Device Identifier: %s\n",
1079 			&vpd->device_identifier[0]);
1080 		break;
1081 	case 0x03: /* UTF-8 */
1082 		snprintf(buf, sizeof(buf),
1083 			"T10 VPD UTF-8 Device Identifier: %s\n",
1084 			&vpd->device_identifier[0]);
1085 		break;
1086 	default:
1087 		sprintf(buf, "T10 VPD Device Identifier encoding unsupported:"
1088 			" 0x%02x", vpd->device_identifier_code_set);
1089 		ret = -EINVAL;
1090 		break;
1091 	}
1092 
1093 	if (p_buf)
1094 		strncpy(p_buf, buf, p_buf_len);
1095 	else
1096 		pr_debug("%s", buf);
1097 
1098 	return ret;
1099 }
1100 
1101 int
1102 transport_set_vpd_ident(struct t10_vpd *vpd, unsigned char *page_83)
1103 {
1104 	static const char hex_str[] = "0123456789abcdef";
1105 	int j = 0, i = 4; /* offset to start of the identifier */
1106 
1107 	/*
1108 	 * The VPD Code Set (encoding)
1109 	 *
1110 	 * from spc3r23.pdf Section 7.6.3.1 Table 296
1111 	 */
1112 	vpd->device_identifier_code_set = (page_83[0] & 0x0f);
1113 	switch (vpd->device_identifier_code_set) {
1114 	case 0x01: /* Binary */
1115 		vpd->device_identifier[j++] =
1116 				hex_str[vpd->device_identifier_type];
1117 		while (i < (4 + page_83[3])) {
1118 			vpd->device_identifier[j++] =
1119 				hex_str[(page_83[i] & 0xf0) >> 4];
1120 			vpd->device_identifier[j++] =
1121 				hex_str[page_83[i] & 0x0f];
1122 			i++;
1123 		}
1124 		break;
1125 	case 0x02: /* ASCII */
1126 	case 0x03: /* UTF-8 */
1127 		while (i < (4 + page_83[3]))
1128 			vpd->device_identifier[j++] = page_83[i++];
1129 		break;
1130 	default:
1131 		break;
1132 	}
1133 
1134 	return transport_dump_vpd_ident(vpd, NULL, 0);
1135 }
1136 EXPORT_SYMBOL(transport_set_vpd_ident);
1137 
1138 static sense_reason_t
1139 target_check_max_data_sg_nents(struct se_cmd *cmd, struct se_device *dev,
1140 			       unsigned int size)
1141 {
1142 	u32 mtl;
1143 
1144 	if (!cmd->se_tfo->max_data_sg_nents)
1145 		return TCM_NO_SENSE;
1146 	/*
1147 	 * Check if fabric enforced maximum SGL entries per I/O descriptor
1148 	 * exceeds se_cmd->data_length.  If true, set SCF_UNDERFLOW_BIT +
1149 	 * residual_count and reduce original cmd->data_length to maximum
1150 	 * length based on single PAGE_SIZE entry scatter-lists.
1151 	 */
1152 	mtl = (cmd->se_tfo->max_data_sg_nents * PAGE_SIZE);
1153 	if (cmd->data_length > mtl) {
1154 		/*
1155 		 * If an existing CDB overflow is present, calculate new residual
1156 		 * based on CDB size minus fabric maximum transfer length.
1157 		 *
1158 		 * If an existing CDB underflow is present, calculate new residual
1159 		 * based on original cmd->data_length minus fabric maximum transfer
1160 		 * length.
1161 		 *
1162 		 * Otherwise, set the underflow residual based on cmd->data_length
1163 		 * minus fabric maximum transfer length.
1164 		 */
1165 		if (cmd->se_cmd_flags & SCF_OVERFLOW_BIT) {
1166 			cmd->residual_count = (size - mtl);
1167 		} else if (cmd->se_cmd_flags & SCF_UNDERFLOW_BIT) {
1168 			u32 orig_dl = size + cmd->residual_count;
1169 			cmd->residual_count = (orig_dl - mtl);
1170 		} else {
1171 			cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
1172 			cmd->residual_count = (cmd->data_length - mtl);
1173 		}
1174 		cmd->data_length = mtl;
1175 		/*
1176 		 * Reset sbc_check_prot() calculated protection payload
1177 		 * length based upon the new smaller MTL.
1178 		 */
1179 		if (cmd->prot_length) {
1180 			u32 sectors = (mtl / dev->dev_attrib.block_size);
1181 			cmd->prot_length = dev->prot_length * sectors;
1182 		}
1183 	}
1184 	return TCM_NO_SENSE;
1185 }
1186 
1187 sense_reason_t
1188 target_cmd_size_check(struct se_cmd *cmd, unsigned int size)
1189 {
1190 	struct se_device *dev = cmd->se_dev;
1191 
1192 	if (cmd->unknown_data_length) {
1193 		cmd->data_length = size;
1194 	} else if (size != cmd->data_length) {
1195 		pr_warn_ratelimited("TARGET_CORE[%s]: Expected Transfer Length:"
1196 			" %u does not match SCSI CDB Length: %u for SAM Opcode:"
1197 			" 0x%02x\n", cmd->se_tfo->get_fabric_name(),
1198 				cmd->data_length, size, cmd->t_task_cdb[0]);
1199 
1200 		if (cmd->data_direction == DMA_TO_DEVICE) {
1201 			if (cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) {
1202 				pr_err_ratelimited("Rejecting underflow/overflow"
1203 						   " for WRITE data CDB\n");
1204 				return TCM_INVALID_CDB_FIELD;
1205 			}
1206 			/*
1207 			 * Some fabric drivers like iscsi-target still expect to
1208 			 * always reject overflow writes.  Reject this case until
1209 			 * full fabric driver level support for overflow writes
1210 			 * is introduced tree-wide.
1211 			 */
1212 			if (size > cmd->data_length) {
1213 				pr_err_ratelimited("Rejecting overflow for"
1214 						   " WRITE control CDB\n");
1215 				return TCM_INVALID_CDB_FIELD;
1216 			}
1217 		}
1218 		/*
1219 		 * Reject READ_* or WRITE_* with overflow/underflow for
1220 		 * type SCF_SCSI_DATA_CDB.
1221 		 */
1222 		if (dev->dev_attrib.block_size != 512)  {
1223 			pr_err("Failing OVERFLOW/UNDERFLOW for LBA op"
1224 				" CDB on non 512-byte sector setup subsystem"
1225 				" plugin: %s\n", dev->transport->name);
1226 			/* Returns CHECK_CONDITION + INVALID_CDB_FIELD */
1227 			return TCM_INVALID_CDB_FIELD;
1228 		}
1229 		/*
1230 		 * For the overflow case keep the existing fabric provided
1231 		 * ->data_length.  Otherwise for the underflow case, reset
1232 		 * ->data_length to the smaller SCSI expected data transfer
1233 		 * length.
1234 		 */
1235 		if (size > cmd->data_length) {
1236 			cmd->se_cmd_flags |= SCF_OVERFLOW_BIT;
1237 			cmd->residual_count = (size - cmd->data_length);
1238 		} else {
1239 			cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
1240 			cmd->residual_count = (cmd->data_length - size);
1241 			cmd->data_length = size;
1242 		}
1243 	}
1244 
1245 	return target_check_max_data_sg_nents(cmd, dev, size);
1246 
1247 }
1248 
1249 /*
1250  * Used by fabric modules containing a local struct se_cmd within their
1251  * fabric dependent per I/O descriptor.
1252  *
1253  * Preserves the value of @cmd->tag.
1254  */
1255 void transport_init_se_cmd(
1256 	struct se_cmd *cmd,
1257 	const struct target_core_fabric_ops *tfo,
1258 	struct se_session *se_sess,
1259 	u32 data_length,
1260 	int data_direction,
1261 	int task_attr,
1262 	unsigned char *sense_buffer)
1263 {
1264 	INIT_LIST_HEAD(&cmd->se_delayed_node);
1265 	INIT_LIST_HEAD(&cmd->se_qf_node);
1266 	INIT_LIST_HEAD(&cmd->se_cmd_list);
1267 	INIT_LIST_HEAD(&cmd->state_list);
1268 	init_completion(&cmd->t_transport_stop_comp);
1269 	init_completion(&cmd->cmd_wait_comp);
1270 	spin_lock_init(&cmd->t_state_lock);
1271 	INIT_WORK(&cmd->work, NULL);
1272 	kref_init(&cmd->cmd_kref);
1273 
1274 	cmd->se_tfo = tfo;
1275 	cmd->se_sess = se_sess;
1276 	cmd->data_length = data_length;
1277 	cmd->data_direction = data_direction;
1278 	cmd->sam_task_attr = task_attr;
1279 	cmd->sense_buffer = sense_buffer;
1280 
1281 	cmd->state_active = false;
1282 }
1283 EXPORT_SYMBOL(transport_init_se_cmd);
1284 
1285 static sense_reason_t
1286 transport_check_alloc_task_attr(struct se_cmd *cmd)
1287 {
1288 	struct se_device *dev = cmd->se_dev;
1289 
1290 	/*
1291 	 * Check if SAM Task Attribute emulation is enabled for this
1292 	 * struct se_device storage object
1293 	 */
1294 	if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
1295 		return 0;
1296 
1297 	if (cmd->sam_task_attr == TCM_ACA_TAG) {
1298 		pr_debug("SAM Task Attribute ACA"
1299 			" emulation is not supported\n");
1300 		return TCM_INVALID_CDB_FIELD;
1301 	}
1302 
1303 	return 0;
1304 }
1305 
1306 sense_reason_t
1307 target_setup_cmd_from_cdb(struct se_cmd *cmd, unsigned char *cdb)
1308 {
1309 	struct se_device *dev = cmd->se_dev;
1310 	sense_reason_t ret;
1311 
1312 	/*
1313 	 * Ensure that the received CDB is less than the max (252 + 8) bytes
1314 	 * for VARIABLE_LENGTH_CMD
1315 	 */
1316 	if (scsi_command_size(cdb) > SCSI_MAX_VARLEN_CDB_SIZE) {
1317 		pr_err("Received SCSI CDB with command_size: %d that"
1318 			" exceeds SCSI_MAX_VARLEN_CDB_SIZE: %d\n",
1319 			scsi_command_size(cdb), SCSI_MAX_VARLEN_CDB_SIZE);
1320 		return TCM_INVALID_CDB_FIELD;
1321 	}
1322 	/*
1323 	 * If the received CDB is larger than TCM_MAX_COMMAND_SIZE,
1324 	 * allocate the additional extended CDB buffer now..  Otherwise
1325 	 * setup the pointer from __t_task_cdb to t_task_cdb.
1326 	 */
1327 	if (scsi_command_size(cdb) > sizeof(cmd->__t_task_cdb)) {
1328 		cmd->t_task_cdb = kzalloc(scsi_command_size(cdb),
1329 						GFP_KERNEL);
1330 		if (!cmd->t_task_cdb) {
1331 			pr_err("Unable to allocate cmd->t_task_cdb"
1332 				" %u > sizeof(cmd->__t_task_cdb): %lu ops\n",
1333 				scsi_command_size(cdb),
1334 				(unsigned long)sizeof(cmd->__t_task_cdb));
1335 			return TCM_OUT_OF_RESOURCES;
1336 		}
1337 	} else
1338 		cmd->t_task_cdb = &cmd->__t_task_cdb[0];
1339 	/*
1340 	 * Copy the original CDB into cmd->
1341 	 */
1342 	memcpy(cmd->t_task_cdb, cdb, scsi_command_size(cdb));
1343 
1344 	trace_target_sequencer_start(cmd);
1345 
1346 	ret = dev->transport->parse_cdb(cmd);
1347 	if (ret == TCM_UNSUPPORTED_SCSI_OPCODE)
1348 		pr_warn_ratelimited("%s/%s: Unsupported SCSI Opcode 0x%02x, sending CHECK_CONDITION.\n",
1349 				    cmd->se_tfo->get_fabric_name(),
1350 				    cmd->se_sess->se_node_acl->initiatorname,
1351 				    cmd->t_task_cdb[0]);
1352 	if (ret)
1353 		return ret;
1354 
1355 	ret = transport_check_alloc_task_attr(cmd);
1356 	if (ret)
1357 		return ret;
1358 
1359 	cmd->se_cmd_flags |= SCF_SUPPORTED_SAM_OPCODE;
1360 	atomic_long_inc(&cmd->se_lun->lun_stats.cmd_pdus);
1361 	return 0;
1362 }
1363 EXPORT_SYMBOL(target_setup_cmd_from_cdb);
1364 
1365 /*
1366  * Used by fabric module frontends to queue tasks directly.
1367  * May only be used from process context.
1368  */
1369 int transport_handle_cdb_direct(
1370 	struct se_cmd *cmd)
1371 {
1372 	sense_reason_t ret;
1373 
1374 	if (!cmd->se_lun) {
1375 		dump_stack();
1376 		pr_err("cmd->se_lun is NULL\n");
1377 		return -EINVAL;
1378 	}
1379 	if (in_interrupt()) {
1380 		dump_stack();
1381 		pr_err("transport_generic_handle_cdb cannot be called"
1382 				" from interrupt context\n");
1383 		return -EINVAL;
1384 	}
1385 	/*
1386 	 * Set TRANSPORT_NEW_CMD state and CMD_T_ACTIVE to ensure that
1387 	 * outstanding descriptors are handled correctly during shutdown via
1388 	 * transport_wait_for_tasks()
1389 	 *
1390 	 * Also, we don't take cmd->t_state_lock here as we only expect
1391 	 * this to be called for initial descriptor submission.
1392 	 */
1393 	cmd->t_state = TRANSPORT_NEW_CMD;
1394 	cmd->transport_state |= CMD_T_ACTIVE;
1395 
1396 	/*
1397 	 * transport_generic_new_cmd() is already handling QUEUE_FULL,
1398 	 * so follow TRANSPORT_NEW_CMD processing thread context usage
1399 	 * and call transport_generic_request_failure() if necessary..
1400 	 */
1401 	ret = transport_generic_new_cmd(cmd);
1402 	if (ret)
1403 		transport_generic_request_failure(cmd, ret);
1404 	return 0;
1405 }
1406 EXPORT_SYMBOL(transport_handle_cdb_direct);
1407 
1408 sense_reason_t
1409 transport_generic_map_mem_to_cmd(struct se_cmd *cmd, struct scatterlist *sgl,
1410 		u32 sgl_count, struct scatterlist *sgl_bidi, u32 sgl_bidi_count)
1411 {
1412 	if (!sgl || !sgl_count)
1413 		return 0;
1414 
1415 	/*
1416 	 * Reject SCSI data overflow with map_mem_to_cmd() as incoming
1417 	 * scatterlists already have been set to follow what the fabric
1418 	 * passes for the original expected data transfer length.
1419 	 */
1420 	if (cmd->se_cmd_flags & SCF_OVERFLOW_BIT) {
1421 		pr_warn("Rejecting SCSI DATA overflow for fabric using"
1422 			" SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC\n");
1423 		return TCM_INVALID_CDB_FIELD;
1424 	}
1425 
1426 	cmd->t_data_sg = sgl;
1427 	cmd->t_data_nents = sgl_count;
1428 	cmd->t_bidi_data_sg = sgl_bidi;
1429 	cmd->t_bidi_data_nents = sgl_bidi_count;
1430 
1431 	cmd->se_cmd_flags |= SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC;
1432 	return 0;
1433 }
1434 
1435 /*
1436  * target_submit_cmd_map_sgls - lookup unpacked lun and submit uninitialized
1437  * 			 se_cmd + use pre-allocated SGL memory.
1438  *
1439  * @se_cmd: command descriptor to submit
1440  * @se_sess: associated se_sess for endpoint
1441  * @cdb: pointer to SCSI CDB
1442  * @sense: pointer to SCSI sense buffer
1443  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1444  * @data_length: fabric expected data transfer length
1445  * @task_addr: SAM task attribute
1446  * @data_dir: DMA data direction
1447  * @flags: flags for command submission from target_sc_flags_tables
1448  * @sgl: struct scatterlist memory for unidirectional mapping
1449  * @sgl_count: scatterlist count for unidirectional mapping
1450  * @sgl_bidi: struct scatterlist memory for bidirectional READ mapping
1451  * @sgl_bidi_count: scatterlist count for bidirectional READ mapping
1452  * @sgl_prot: struct scatterlist memory protection information
1453  * @sgl_prot_count: scatterlist count for protection information
1454  *
1455  * Task tags are supported if the caller has set @se_cmd->tag.
1456  *
1457  * Returns non zero to signal active I/O shutdown failure.  All other
1458  * setup exceptions will be returned as a SCSI CHECK_CONDITION response,
1459  * but still return zero here.
1460  *
1461  * This may only be called from process context, and also currently
1462  * assumes internal allocation of fabric payload buffer by target-core.
1463  */
1464 int target_submit_cmd_map_sgls(struct se_cmd *se_cmd, struct se_session *se_sess,
1465 		unsigned char *cdb, unsigned char *sense, u64 unpacked_lun,
1466 		u32 data_length, int task_attr, int data_dir, int flags,
1467 		struct scatterlist *sgl, u32 sgl_count,
1468 		struct scatterlist *sgl_bidi, u32 sgl_bidi_count,
1469 		struct scatterlist *sgl_prot, u32 sgl_prot_count)
1470 {
1471 	struct se_portal_group *se_tpg;
1472 	sense_reason_t rc;
1473 	int ret;
1474 
1475 	se_tpg = se_sess->se_tpg;
1476 	BUG_ON(!se_tpg);
1477 	BUG_ON(se_cmd->se_tfo || se_cmd->se_sess);
1478 	BUG_ON(in_interrupt());
1479 	/*
1480 	 * Initialize se_cmd for target operation.  From this point
1481 	 * exceptions are handled by sending exception status via
1482 	 * target_core_fabric_ops->queue_status() callback
1483 	 */
1484 	transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess,
1485 				data_length, data_dir, task_attr, sense);
1486 
1487 	if (flags & TARGET_SCF_USE_CPUID)
1488 		se_cmd->se_cmd_flags |= SCF_USE_CPUID;
1489 	else
1490 		se_cmd->cpuid = WORK_CPU_UNBOUND;
1491 
1492 	if (flags & TARGET_SCF_UNKNOWN_SIZE)
1493 		se_cmd->unknown_data_length = 1;
1494 	/*
1495 	 * Obtain struct se_cmd->cmd_kref reference and add new cmd to
1496 	 * se_sess->sess_cmd_list.  A second kref_get here is necessary
1497 	 * for fabrics using TARGET_SCF_ACK_KREF that expect a second
1498 	 * kref_put() to happen during fabric packet acknowledgement.
1499 	 */
1500 	ret = target_get_sess_cmd(se_cmd, flags & TARGET_SCF_ACK_KREF);
1501 	if (ret)
1502 		return ret;
1503 	/*
1504 	 * Signal bidirectional data payloads to target-core
1505 	 */
1506 	if (flags & TARGET_SCF_BIDI_OP)
1507 		se_cmd->se_cmd_flags |= SCF_BIDI;
1508 	/*
1509 	 * Locate se_lun pointer and attach it to struct se_cmd
1510 	 */
1511 	rc = transport_lookup_cmd_lun(se_cmd, unpacked_lun);
1512 	if (rc) {
1513 		transport_send_check_condition_and_sense(se_cmd, rc, 0);
1514 		target_put_sess_cmd(se_cmd);
1515 		return 0;
1516 	}
1517 
1518 	rc = target_setup_cmd_from_cdb(se_cmd, cdb);
1519 	if (rc != 0) {
1520 		transport_generic_request_failure(se_cmd, rc);
1521 		return 0;
1522 	}
1523 
1524 	/*
1525 	 * Save pointers for SGLs containing protection information,
1526 	 * if present.
1527 	 */
1528 	if (sgl_prot_count) {
1529 		se_cmd->t_prot_sg = sgl_prot;
1530 		se_cmd->t_prot_nents = sgl_prot_count;
1531 		se_cmd->se_cmd_flags |= SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC;
1532 	}
1533 
1534 	/*
1535 	 * When a non zero sgl_count has been passed perform SGL passthrough
1536 	 * mapping for pre-allocated fabric memory instead of having target
1537 	 * core perform an internal SGL allocation..
1538 	 */
1539 	if (sgl_count != 0) {
1540 		BUG_ON(!sgl);
1541 
1542 		/*
1543 		 * A work-around for tcm_loop as some userspace code via
1544 		 * scsi-generic do not memset their associated read buffers,
1545 		 * so go ahead and do that here for type non-data CDBs.  Also
1546 		 * note that this is currently guaranteed to be a single SGL
1547 		 * for this case by target core in target_setup_cmd_from_cdb()
1548 		 * -> transport_generic_cmd_sequencer().
1549 		 */
1550 		if (!(se_cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) &&
1551 		     se_cmd->data_direction == DMA_FROM_DEVICE) {
1552 			unsigned char *buf = NULL;
1553 
1554 			if (sgl)
1555 				buf = kmap(sg_page(sgl)) + sgl->offset;
1556 
1557 			if (buf) {
1558 				memset(buf, 0, sgl->length);
1559 				kunmap(sg_page(sgl));
1560 			}
1561 		}
1562 
1563 		rc = transport_generic_map_mem_to_cmd(se_cmd, sgl, sgl_count,
1564 				sgl_bidi, sgl_bidi_count);
1565 		if (rc != 0) {
1566 			transport_generic_request_failure(se_cmd, rc);
1567 			return 0;
1568 		}
1569 	}
1570 
1571 	/*
1572 	 * Check if we need to delay processing because of ALUA
1573 	 * Active/NonOptimized primary access state..
1574 	 */
1575 	core_alua_check_nonop_delay(se_cmd);
1576 
1577 	transport_handle_cdb_direct(se_cmd);
1578 	return 0;
1579 }
1580 EXPORT_SYMBOL(target_submit_cmd_map_sgls);
1581 
1582 /*
1583  * target_submit_cmd - lookup unpacked lun and submit uninitialized se_cmd
1584  *
1585  * @se_cmd: command descriptor to submit
1586  * @se_sess: associated se_sess for endpoint
1587  * @cdb: pointer to SCSI CDB
1588  * @sense: pointer to SCSI sense buffer
1589  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1590  * @data_length: fabric expected data transfer length
1591  * @task_addr: SAM task attribute
1592  * @data_dir: DMA data direction
1593  * @flags: flags for command submission from target_sc_flags_tables
1594  *
1595  * Task tags are supported if the caller has set @se_cmd->tag.
1596  *
1597  * Returns non zero to signal active I/O shutdown failure.  All other
1598  * setup exceptions will be returned as a SCSI CHECK_CONDITION response,
1599  * but still return zero here.
1600  *
1601  * This may only be called from process context, and also currently
1602  * assumes internal allocation of fabric payload buffer by target-core.
1603  *
1604  * It also assumes interal target core SGL memory allocation.
1605  */
1606 int target_submit_cmd(struct se_cmd *se_cmd, struct se_session *se_sess,
1607 		unsigned char *cdb, unsigned char *sense, u64 unpacked_lun,
1608 		u32 data_length, int task_attr, int data_dir, int flags)
1609 {
1610 	return target_submit_cmd_map_sgls(se_cmd, se_sess, cdb, sense,
1611 			unpacked_lun, data_length, task_attr, data_dir,
1612 			flags, NULL, 0, NULL, 0, NULL, 0);
1613 }
1614 EXPORT_SYMBOL(target_submit_cmd);
1615 
1616 static void target_complete_tmr_failure(struct work_struct *work)
1617 {
1618 	struct se_cmd *se_cmd = container_of(work, struct se_cmd, work);
1619 
1620 	se_cmd->se_tmr_req->response = TMR_LUN_DOES_NOT_EXIST;
1621 	se_cmd->se_tfo->queue_tm_rsp(se_cmd);
1622 
1623 	transport_lun_remove_cmd(se_cmd);
1624 	transport_cmd_check_stop_to_fabric(se_cmd);
1625 }
1626 
1627 static bool target_lookup_lun_from_tag(struct se_session *se_sess, u64 tag,
1628 				       u64 *unpacked_lun)
1629 {
1630 	struct se_cmd *se_cmd;
1631 	unsigned long flags;
1632 	bool ret = false;
1633 
1634 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
1635 	list_for_each_entry(se_cmd, &se_sess->sess_cmd_list, se_cmd_list) {
1636 		if (se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
1637 			continue;
1638 
1639 		if (se_cmd->tag == tag) {
1640 			*unpacked_lun = se_cmd->orig_fe_lun;
1641 			ret = true;
1642 			break;
1643 		}
1644 	}
1645 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
1646 
1647 	return ret;
1648 }
1649 
1650 /**
1651  * target_submit_tmr - lookup unpacked lun and submit uninitialized se_cmd
1652  *                     for TMR CDBs
1653  *
1654  * @se_cmd: command descriptor to submit
1655  * @se_sess: associated se_sess for endpoint
1656  * @sense: pointer to SCSI sense buffer
1657  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1658  * @fabric_context: fabric context for TMR req
1659  * @tm_type: Type of TM request
1660  * @gfp: gfp type for caller
1661  * @tag: referenced task tag for TMR_ABORT_TASK
1662  * @flags: submit cmd flags
1663  *
1664  * Callable from all contexts.
1665  **/
1666 
1667 int target_submit_tmr(struct se_cmd *se_cmd, struct se_session *se_sess,
1668 		unsigned char *sense, u64 unpacked_lun,
1669 		void *fabric_tmr_ptr, unsigned char tm_type,
1670 		gfp_t gfp, u64 tag, int flags)
1671 {
1672 	struct se_portal_group *se_tpg;
1673 	int ret;
1674 
1675 	se_tpg = se_sess->se_tpg;
1676 	BUG_ON(!se_tpg);
1677 
1678 	transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess,
1679 			      0, DMA_NONE, TCM_SIMPLE_TAG, sense);
1680 	/*
1681 	 * FIXME: Currently expect caller to handle se_cmd->se_tmr_req
1682 	 * allocation failure.
1683 	 */
1684 	ret = core_tmr_alloc_req(se_cmd, fabric_tmr_ptr, tm_type, gfp);
1685 	if (ret < 0)
1686 		return -ENOMEM;
1687 
1688 	if (tm_type == TMR_ABORT_TASK)
1689 		se_cmd->se_tmr_req->ref_task_tag = tag;
1690 
1691 	/* See target_submit_cmd for commentary */
1692 	ret = target_get_sess_cmd(se_cmd, flags & TARGET_SCF_ACK_KREF);
1693 	if (ret) {
1694 		core_tmr_release_req(se_cmd->se_tmr_req);
1695 		return ret;
1696 	}
1697 	/*
1698 	 * If this is ABORT_TASK with no explicit fabric provided LUN,
1699 	 * go ahead and search active session tags for a match to figure
1700 	 * out unpacked_lun for the original se_cmd.
1701 	 */
1702 	if (tm_type == TMR_ABORT_TASK && (flags & TARGET_SCF_LOOKUP_LUN_FROM_TAG)) {
1703 		if (!target_lookup_lun_from_tag(se_sess, tag, &unpacked_lun))
1704 			goto failure;
1705 	}
1706 
1707 	ret = transport_lookup_tmr_lun(se_cmd, unpacked_lun);
1708 	if (ret)
1709 		goto failure;
1710 
1711 	transport_generic_handle_tmr(se_cmd);
1712 	return 0;
1713 
1714 	/*
1715 	 * For callback during failure handling, push this work off
1716 	 * to process context with TMR_LUN_DOES_NOT_EXIST status.
1717 	 */
1718 failure:
1719 	INIT_WORK(&se_cmd->work, target_complete_tmr_failure);
1720 	schedule_work(&se_cmd->work);
1721 	return 0;
1722 }
1723 EXPORT_SYMBOL(target_submit_tmr);
1724 
1725 /*
1726  * Handle SAM-esque emulation for generic transport request failures.
1727  */
1728 void transport_generic_request_failure(struct se_cmd *cmd,
1729 		sense_reason_t sense_reason)
1730 {
1731 	int ret = 0, post_ret = 0;
1732 
1733 	if (transport_check_aborted_status(cmd, 1))
1734 		return;
1735 
1736 	pr_debug("-----[ Storage Engine Exception; sense_reason %d\n",
1737 		 sense_reason);
1738 	target_show_cmd("-----[ ", cmd);
1739 
1740 	/*
1741 	 * For SAM Task Attribute emulation for failed struct se_cmd
1742 	 */
1743 	transport_complete_task_attr(cmd);
1744 	/*
1745 	 * Handle special case for COMPARE_AND_WRITE failure, where the
1746 	 * callback is expected to drop the per device ->caw_sem.
1747 	 */
1748 	if ((cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) &&
1749 	     cmd->transport_complete_callback)
1750 		cmd->transport_complete_callback(cmd, false, &post_ret);
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 		sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
1776 		break;
1777 	case TCM_RESERVATION_CONFLICT:
1778 		/*
1779 		 * No SENSE Data payload for this case, set SCSI Status
1780 		 * and queue the response to $FABRIC_MOD.
1781 		 *
1782 		 * Uses linux/include/scsi/scsi.h SAM status codes defs
1783 		 */
1784 		cmd->scsi_status = SAM_STAT_RESERVATION_CONFLICT;
1785 		/*
1786 		 * For UA Interlock Code 11b, a RESERVATION CONFLICT will
1787 		 * establish a UNIT ATTENTION with PREVIOUS RESERVATION
1788 		 * CONFLICT STATUS.
1789 		 *
1790 		 * See spc4r17, section 7.4.6 Control Mode Page, Table 349
1791 		 */
1792 		if (cmd->se_sess &&
1793 		    cmd->se_dev->dev_attrib.emulate_ua_intlck_ctrl == 2) {
1794 			target_ua_allocate_lun(cmd->se_sess->se_node_acl,
1795 					       cmd->orig_fe_lun, 0x2C,
1796 					ASCQ_2CH_PREVIOUS_RESERVATION_CONFLICT_STATUS);
1797 		}
1798 		trace_target_cmd_complete(cmd);
1799 		ret = cmd->se_tfo->queue_status(cmd);
1800 		if (ret)
1801 			goto queue_full;
1802 		goto check_stop;
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_full:
1820 	transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
1821 }
1822 EXPORT_SYMBOL(transport_generic_request_failure);
1823 
1824 void __target_execute_cmd(struct se_cmd *cmd, bool do_checks)
1825 {
1826 	sense_reason_t ret;
1827 
1828 	if (!cmd->execute_cmd) {
1829 		ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
1830 		goto err;
1831 	}
1832 	if (do_checks) {
1833 		/*
1834 		 * Check for an existing UNIT ATTENTION condition after
1835 		 * target_handle_task_attr() has done SAM task attr
1836 		 * checking, and possibly have already defered execution
1837 		 * out to target_restart_delayed_cmds() context.
1838 		 */
1839 		ret = target_scsi3_ua_check(cmd);
1840 		if (ret)
1841 			goto err;
1842 
1843 		ret = target_alua_state_check(cmd);
1844 		if (ret)
1845 			goto err;
1846 
1847 		ret = target_check_reservation(cmd);
1848 		if (ret) {
1849 			cmd->scsi_status = SAM_STAT_RESERVATION_CONFLICT;
1850 			goto err;
1851 		}
1852 	}
1853 
1854 	ret = cmd->execute_cmd(cmd);
1855 	if (!ret)
1856 		return;
1857 err:
1858 	spin_lock_irq(&cmd->t_state_lock);
1859 	cmd->transport_state &= ~CMD_T_SENT;
1860 	spin_unlock_irq(&cmd->t_state_lock);
1861 
1862 	transport_generic_request_failure(cmd, ret);
1863 }
1864 
1865 static int target_write_prot_action(struct se_cmd *cmd)
1866 {
1867 	u32 sectors;
1868 	/*
1869 	 * Perform WRITE_INSERT of PI using software emulation when backend
1870 	 * device has PI enabled, if the transport has not already generated
1871 	 * PI using hardware WRITE_INSERT offload.
1872 	 */
1873 	switch (cmd->prot_op) {
1874 	case TARGET_PROT_DOUT_INSERT:
1875 		if (!(cmd->se_sess->sup_prot_ops & TARGET_PROT_DOUT_INSERT))
1876 			sbc_dif_generate(cmd);
1877 		break;
1878 	case TARGET_PROT_DOUT_STRIP:
1879 		if (cmd->se_sess->sup_prot_ops & TARGET_PROT_DOUT_STRIP)
1880 			break;
1881 
1882 		sectors = cmd->data_length >> ilog2(cmd->se_dev->dev_attrib.block_size);
1883 		cmd->pi_err = sbc_dif_verify(cmd, cmd->t_task_lba,
1884 					     sectors, 0, cmd->t_prot_sg, 0);
1885 		if (unlikely(cmd->pi_err)) {
1886 			spin_lock_irq(&cmd->t_state_lock);
1887 			cmd->transport_state &= ~CMD_T_SENT;
1888 			spin_unlock_irq(&cmd->t_state_lock);
1889 			transport_generic_request_failure(cmd, cmd->pi_err);
1890 			return -1;
1891 		}
1892 		break;
1893 	default:
1894 		break;
1895 	}
1896 
1897 	return 0;
1898 }
1899 
1900 static bool target_handle_task_attr(struct se_cmd *cmd)
1901 {
1902 	struct se_device *dev = cmd->se_dev;
1903 
1904 	if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
1905 		return false;
1906 
1907 	cmd->se_cmd_flags |= SCF_TASK_ATTR_SET;
1908 
1909 	/*
1910 	 * Check for the existence of HEAD_OF_QUEUE, and if true return 1
1911 	 * to allow the passed struct se_cmd list of tasks to the front of the list.
1912 	 */
1913 	switch (cmd->sam_task_attr) {
1914 	case TCM_HEAD_TAG:
1915 		pr_debug("Added HEAD_OF_QUEUE for CDB: 0x%02x\n",
1916 			 cmd->t_task_cdb[0]);
1917 		return false;
1918 	case TCM_ORDERED_TAG:
1919 		atomic_inc_mb(&dev->dev_ordered_sync);
1920 
1921 		pr_debug("Added ORDERED for CDB: 0x%02x to ordered list\n",
1922 			 cmd->t_task_cdb[0]);
1923 
1924 		/*
1925 		 * Execute an ORDERED command if no other older commands
1926 		 * exist that need to be completed first.
1927 		 */
1928 		if (!atomic_read(&dev->simple_cmds))
1929 			return false;
1930 		break;
1931 	default:
1932 		/*
1933 		 * For SIMPLE and UNTAGGED Task Attribute commands
1934 		 */
1935 		atomic_inc_mb(&dev->simple_cmds);
1936 		break;
1937 	}
1938 
1939 	if (atomic_read(&dev->dev_ordered_sync) == 0)
1940 		return false;
1941 
1942 	spin_lock(&dev->delayed_cmd_lock);
1943 	list_add_tail(&cmd->se_delayed_node, &dev->delayed_cmd_list);
1944 	spin_unlock(&dev->delayed_cmd_lock);
1945 
1946 	pr_debug("Added CDB: 0x%02x Task Attr: 0x%02x to delayed CMD listn",
1947 		cmd->t_task_cdb[0], cmd->sam_task_attr);
1948 	return true;
1949 }
1950 
1951 static int __transport_check_aborted_status(struct se_cmd *, int);
1952 
1953 void target_execute_cmd(struct se_cmd *cmd)
1954 {
1955 	/*
1956 	 * Determine if frontend context caller is requesting the stopping of
1957 	 * this command for frontend exceptions.
1958 	 *
1959 	 * If the received CDB has aleady been aborted stop processing it here.
1960 	 */
1961 	spin_lock_irq(&cmd->t_state_lock);
1962 	if (__transport_check_aborted_status(cmd, 1)) {
1963 		spin_unlock_irq(&cmd->t_state_lock);
1964 		return;
1965 	}
1966 	if (cmd->transport_state & CMD_T_STOP) {
1967 		pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08llx\n",
1968 			__func__, __LINE__, cmd->tag);
1969 
1970 		spin_unlock_irq(&cmd->t_state_lock);
1971 		complete_all(&cmd->t_transport_stop_comp);
1972 		return;
1973 	}
1974 
1975 	cmd->t_state = TRANSPORT_PROCESSING;
1976 	cmd->transport_state |= CMD_T_ACTIVE | CMD_T_SENT;
1977 	spin_unlock_irq(&cmd->t_state_lock);
1978 
1979 	if (target_write_prot_action(cmd))
1980 		return;
1981 
1982 	if (target_handle_task_attr(cmd)) {
1983 		spin_lock_irq(&cmd->t_state_lock);
1984 		cmd->transport_state &= ~CMD_T_SENT;
1985 		spin_unlock_irq(&cmd->t_state_lock);
1986 		return;
1987 	}
1988 
1989 	__target_execute_cmd(cmd, true);
1990 }
1991 EXPORT_SYMBOL(target_execute_cmd);
1992 
1993 /*
1994  * Process all commands up to the last received ORDERED task attribute which
1995  * requires another blocking boundary
1996  */
1997 static void target_restart_delayed_cmds(struct se_device *dev)
1998 {
1999 	for (;;) {
2000 		struct se_cmd *cmd;
2001 
2002 		spin_lock(&dev->delayed_cmd_lock);
2003 		if (list_empty(&dev->delayed_cmd_list)) {
2004 			spin_unlock(&dev->delayed_cmd_lock);
2005 			break;
2006 		}
2007 
2008 		cmd = list_entry(dev->delayed_cmd_list.next,
2009 				 struct se_cmd, se_delayed_node);
2010 		list_del(&cmd->se_delayed_node);
2011 		spin_unlock(&dev->delayed_cmd_lock);
2012 
2013 		__target_execute_cmd(cmd, true);
2014 
2015 		if (cmd->sam_task_attr == TCM_ORDERED_TAG)
2016 			break;
2017 	}
2018 }
2019 
2020 /*
2021  * Called from I/O completion to determine which dormant/delayed
2022  * and ordered cmds need to have their tasks added to the execution queue.
2023  */
2024 static void transport_complete_task_attr(struct se_cmd *cmd)
2025 {
2026 	struct se_device *dev = cmd->se_dev;
2027 
2028 	if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
2029 		return;
2030 
2031 	if (!(cmd->se_cmd_flags & SCF_TASK_ATTR_SET))
2032 		goto restart;
2033 
2034 	if (cmd->sam_task_attr == TCM_SIMPLE_TAG) {
2035 		atomic_dec_mb(&dev->simple_cmds);
2036 		dev->dev_cur_ordered_id++;
2037 	} else if (cmd->sam_task_attr == TCM_HEAD_TAG) {
2038 		dev->dev_cur_ordered_id++;
2039 		pr_debug("Incremented dev_cur_ordered_id: %u for HEAD_OF_QUEUE\n",
2040 			 dev->dev_cur_ordered_id);
2041 	} else if (cmd->sam_task_attr == TCM_ORDERED_TAG) {
2042 		atomic_dec_mb(&dev->dev_ordered_sync);
2043 
2044 		dev->dev_cur_ordered_id++;
2045 		pr_debug("Incremented dev_cur_ordered_id: %u for ORDERED\n",
2046 			 dev->dev_cur_ordered_id);
2047 	}
2048 restart:
2049 	target_restart_delayed_cmds(dev);
2050 }
2051 
2052 static void transport_complete_qf(struct se_cmd *cmd)
2053 {
2054 	int ret = 0;
2055 
2056 	transport_complete_task_attr(cmd);
2057 	/*
2058 	 * If a fabric driver ->write_pending() or ->queue_data_in() callback
2059 	 * has returned neither -ENOMEM or -EAGAIN, assume it's fatal and
2060 	 * the same callbacks should not be retried.  Return CHECK_CONDITION
2061 	 * if a scsi_status is not already set.
2062 	 *
2063 	 * If a fabric driver ->queue_status() has returned non zero, always
2064 	 * keep retrying no matter what..
2065 	 */
2066 	if (cmd->t_state == TRANSPORT_COMPLETE_QF_ERR) {
2067 		if (cmd->scsi_status)
2068 			goto queue_status;
2069 
2070 		cmd->se_cmd_flags |= SCF_EMULATED_TASK_SENSE;
2071 		cmd->scsi_status = SAM_STAT_CHECK_CONDITION;
2072 		cmd->scsi_sense_length  = TRANSPORT_SENSE_BUFFER;
2073 		translate_sense_reason(cmd, TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE);
2074 		goto queue_status;
2075 	}
2076 
2077 	if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE)
2078 		goto queue_status;
2079 
2080 	switch (cmd->data_direction) {
2081 	case DMA_FROM_DEVICE:
2082 		if (cmd->scsi_status)
2083 			goto queue_status;
2084 
2085 		trace_target_cmd_complete(cmd);
2086 		ret = cmd->se_tfo->queue_data_in(cmd);
2087 		break;
2088 	case DMA_TO_DEVICE:
2089 		if (cmd->se_cmd_flags & SCF_BIDI) {
2090 			ret = cmd->se_tfo->queue_data_in(cmd);
2091 			break;
2092 		}
2093 		/* Fall through for DMA_TO_DEVICE */
2094 	case DMA_NONE:
2095 queue_status:
2096 		trace_target_cmd_complete(cmd);
2097 		ret = cmd->se_tfo->queue_status(cmd);
2098 		break;
2099 	default:
2100 		break;
2101 	}
2102 
2103 	if (ret < 0) {
2104 		transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
2105 		return;
2106 	}
2107 	transport_lun_remove_cmd(cmd);
2108 	transport_cmd_check_stop_to_fabric(cmd);
2109 }
2110 
2111 static void transport_handle_queue_full(struct se_cmd *cmd, struct se_device *dev,
2112 					int err, bool write_pending)
2113 {
2114 	/*
2115 	 * -EAGAIN or -ENOMEM signals retry of ->write_pending() and/or
2116 	 * ->queue_data_in() callbacks from new process context.
2117 	 *
2118 	 * Otherwise for other errors, transport_complete_qf() will send
2119 	 * CHECK_CONDITION via ->queue_status() instead of attempting to
2120 	 * retry associated fabric driver data-transfer callbacks.
2121 	 */
2122 	if (err == -EAGAIN || err == -ENOMEM) {
2123 		cmd->t_state = (write_pending) ? TRANSPORT_COMPLETE_QF_WP :
2124 						 TRANSPORT_COMPLETE_QF_OK;
2125 	} else {
2126 		pr_warn_ratelimited("Got unknown fabric queue status: %d\n", err);
2127 		cmd->t_state = TRANSPORT_COMPLETE_QF_ERR;
2128 	}
2129 
2130 	spin_lock_irq(&dev->qf_cmd_lock);
2131 	list_add_tail(&cmd->se_qf_node, &cmd->se_dev->qf_cmd_list);
2132 	atomic_inc_mb(&dev->dev_qf_count);
2133 	spin_unlock_irq(&cmd->se_dev->qf_cmd_lock);
2134 
2135 	schedule_work(&cmd->se_dev->qf_work_queue);
2136 }
2137 
2138 static bool target_read_prot_action(struct se_cmd *cmd)
2139 {
2140 	switch (cmd->prot_op) {
2141 	case TARGET_PROT_DIN_STRIP:
2142 		if (!(cmd->se_sess->sup_prot_ops & TARGET_PROT_DIN_STRIP)) {
2143 			u32 sectors = cmd->data_length >>
2144 				  ilog2(cmd->se_dev->dev_attrib.block_size);
2145 
2146 			cmd->pi_err = sbc_dif_verify(cmd, cmd->t_task_lba,
2147 						     sectors, 0, cmd->t_prot_sg,
2148 						     0);
2149 			if (cmd->pi_err)
2150 				return true;
2151 		}
2152 		break;
2153 	case TARGET_PROT_DIN_INSERT:
2154 		if (cmd->se_sess->sup_prot_ops & TARGET_PROT_DIN_INSERT)
2155 			break;
2156 
2157 		sbc_dif_generate(cmd);
2158 		break;
2159 	default:
2160 		break;
2161 	}
2162 
2163 	return false;
2164 }
2165 
2166 static void target_complete_ok_work(struct work_struct *work)
2167 {
2168 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
2169 	int ret;
2170 
2171 	/*
2172 	 * Check if we need to move delayed/dormant tasks from cmds on the
2173 	 * delayed execution list after a HEAD_OF_QUEUE or ORDERED Task
2174 	 * Attribute.
2175 	 */
2176 	transport_complete_task_attr(cmd);
2177 
2178 	/*
2179 	 * Check to schedule QUEUE_FULL work, or execute an existing
2180 	 * cmd->transport_qf_callback()
2181 	 */
2182 	if (atomic_read(&cmd->se_dev->dev_qf_count) != 0)
2183 		schedule_work(&cmd->se_dev->qf_work_queue);
2184 
2185 	/*
2186 	 * Check if we need to send a sense buffer from
2187 	 * the struct se_cmd in question.
2188 	 */
2189 	if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) {
2190 		WARN_ON(!cmd->scsi_status);
2191 		ret = transport_send_check_condition_and_sense(
2192 					cmd, 0, 1);
2193 		if (ret)
2194 			goto queue_full;
2195 
2196 		transport_lun_remove_cmd(cmd);
2197 		transport_cmd_check_stop_to_fabric(cmd);
2198 		return;
2199 	}
2200 	/*
2201 	 * Check for a callback, used by amongst other things
2202 	 * XDWRITE_READ_10 and COMPARE_AND_WRITE emulation.
2203 	 */
2204 	if (cmd->transport_complete_callback) {
2205 		sense_reason_t rc;
2206 		bool caw = (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE);
2207 		bool zero_dl = !(cmd->data_length);
2208 		int post_ret = 0;
2209 
2210 		rc = cmd->transport_complete_callback(cmd, true, &post_ret);
2211 		if (!rc && !post_ret) {
2212 			if (caw && zero_dl)
2213 				goto queue_rsp;
2214 
2215 			return;
2216 		} else if (rc) {
2217 			ret = transport_send_check_condition_and_sense(cmd,
2218 						rc, 0);
2219 			if (ret)
2220 				goto queue_full;
2221 
2222 			transport_lun_remove_cmd(cmd);
2223 			transport_cmd_check_stop_to_fabric(cmd);
2224 			return;
2225 		}
2226 	}
2227 
2228 queue_rsp:
2229 	switch (cmd->data_direction) {
2230 	case DMA_FROM_DEVICE:
2231 		if (cmd->scsi_status)
2232 			goto queue_status;
2233 
2234 		atomic_long_add(cmd->data_length,
2235 				&cmd->se_lun->lun_stats.tx_data_octets);
2236 		/*
2237 		 * Perform READ_STRIP of PI using software emulation when
2238 		 * backend had PI enabled, if the transport will not be
2239 		 * performing hardware READ_STRIP offload.
2240 		 */
2241 		if (target_read_prot_action(cmd)) {
2242 			ret = transport_send_check_condition_and_sense(cmd,
2243 						cmd->pi_err, 0);
2244 			if (ret)
2245 				goto queue_full;
2246 
2247 			transport_lun_remove_cmd(cmd);
2248 			transport_cmd_check_stop_to_fabric(cmd);
2249 			return;
2250 		}
2251 
2252 		trace_target_cmd_complete(cmd);
2253 		ret = cmd->se_tfo->queue_data_in(cmd);
2254 		if (ret)
2255 			goto queue_full;
2256 		break;
2257 	case DMA_TO_DEVICE:
2258 		atomic_long_add(cmd->data_length,
2259 				&cmd->se_lun->lun_stats.rx_data_octets);
2260 		/*
2261 		 * Check if we need to send READ payload for BIDI-COMMAND
2262 		 */
2263 		if (cmd->se_cmd_flags & SCF_BIDI) {
2264 			atomic_long_add(cmd->data_length,
2265 					&cmd->se_lun->lun_stats.tx_data_octets);
2266 			ret = cmd->se_tfo->queue_data_in(cmd);
2267 			if (ret)
2268 				goto queue_full;
2269 			break;
2270 		}
2271 		/* Fall through for DMA_TO_DEVICE */
2272 	case DMA_NONE:
2273 queue_status:
2274 		trace_target_cmd_complete(cmd);
2275 		ret = cmd->se_tfo->queue_status(cmd);
2276 		if (ret)
2277 			goto queue_full;
2278 		break;
2279 	default:
2280 		break;
2281 	}
2282 
2283 	transport_lun_remove_cmd(cmd);
2284 	transport_cmd_check_stop_to_fabric(cmd);
2285 	return;
2286 
2287 queue_full:
2288 	pr_debug("Handling complete_ok QUEUE_FULL: se_cmd: %p,"
2289 		" data_direction: %d\n", cmd, cmd->data_direction);
2290 
2291 	transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
2292 }
2293 
2294 void target_free_sgl(struct scatterlist *sgl, int nents)
2295 {
2296 	struct scatterlist *sg;
2297 	int count;
2298 
2299 	for_each_sg(sgl, sg, nents, count)
2300 		__free_page(sg_page(sg));
2301 
2302 	kfree(sgl);
2303 }
2304 EXPORT_SYMBOL(target_free_sgl);
2305 
2306 static inline void transport_reset_sgl_orig(struct se_cmd *cmd)
2307 {
2308 	/*
2309 	 * Check for saved t_data_sg that may be used for COMPARE_AND_WRITE
2310 	 * emulation, and free + reset pointers if necessary..
2311 	 */
2312 	if (!cmd->t_data_sg_orig)
2313 		return;
2314 
2315 	kfree(cmd->t_data_sg);
2316 	cmd->t_data_sg = cmd->t_data_sg_orig;
2317 	cmd->t_data_sg_orig = NULL;
2318 	cmd->t_data_nents = cmd->t_data_nents_orig;
2319 	cmd->t_data_nents_orig = 0;
2320 }
2321 
2322 static inline void transport_free_pages(struct se_cmd *cmd)
2323 {
2324 	if (!(cmd->se_cmd_flags & SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC)) {
2325 		target_free_sgl(cmd->t_prot_sg, cmd->t_prot_nents);
2326 		cmd->t_prot_sg = NULL;
2327 		cmd->t_prot_nents = 0;
2328 	}
2329 
2330 	if (cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) {
2331 		/*
2332 		 * Release special case READ buffer payload required for
2333 		 * SG_TO_MEM_NOALLOC to function with COMPARE_AND_WRITE
2334 		 */
2335 		if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) {
2336 			target_free_sgl(cmd->t_bidi_data_sg,
2337 					   cmd->t_bidi_data_nents);
2338 			cmd->t_bidi_data_sg = NULL;
2339 			cmd->t_bidi_data_nents = 0;
2340 		}
2341 		transport_reset_sgl_orig(cmd);
2342 		return;
2343 	}
2344 	transport_reset_sgl_orig(cmd);
2345 
2346 	target_free_sgl(cmd->t_data_sg, cmd->t_data_nents);
2347 	cmd->t_data_sg = NULL;
2348 	cmd->t_data_nents = 0;
2349 
2350 	target_free_sgl(cmd->t_bidi_data_sg, cmd->t_bidi_data_nents);
2351 	cmd->t_bidi_data_sg = NULL;
2352 	cmd->t_bidi_data_nents = 0;
2353 }
2354 
2355 /**
2356  * transport_put_cmd - release a reference to a command
2357  * @cmd:       command to release
2358  *
2359  * This routine releases our reference to the command and frees it if possible.
2360  */
2361 static int transport_put_cmd(struct se_cmd *cmd)
2362 {
2363 	BUG_ON(!cmd->se_tfo);
2364 	/*
2365 	 * If this cmd has been setup with target_get_sess_cmd(), drop
2366 	 * the kref and call ->release_cmd() in kref callback.
2367 	 */
2368 	return target_put_sess_cmd(cmd);
2369 }
2370 
2371 void *transport_kmap_data_sg(struct se_cmd *cmd)
2372 {
2373 	struct scatterlist *sg = cmd->t_data_sg;
2374 	struct page **pages;
2375 	int i;
2376 
2377 	/*
2378 	 * We need to take into account a possible offset here for fabrics like
2379 	 * tcm_loop who may be using a contig buffer from the SCSI midlayer for
2380 	 * control CDBs passed as SGLs via transport_generic_map_mem_to_cmd()
2381 	 */
2382 	if (!cmd->t_data_nents)
2383 		return NULL;
2384 
2385 	BUG_ON(!sg);
2386 	if (cmd->t_data_nents == 1)
2387 		return kmap(sg_page(sg)) + sg->offset;
2388 
2389 	/* >1 page. use vmap */
2390 	pages = kmalloc_array(cmd->t_data_nents, sizeof(*pages), GFP_KERNEL);
2391 	if (!pages)
2392 		return NULL;
2393 
2394 	/* convert sg[] to pages[] */
2395 	for_each_sg(cmd->t_data_sg, sg, cmd->t_data_nents, i) {
2396 		pages[i] = sg_page(sg);
2397 	}
2398 
2399 	cmd->t_data_vmap = vmap(pages, cmd->t_data_nents,  VM_MAP, PAGE_KERNEL);
2400 	kfree(pages);
2401 	if (!cmd->t_data_vmap)
2402 		return NULL;
2403 
2404 	return cmd->t_data_vmap + cmd->t_data_sg[0].offset;
2405 }
2406 EXPORT_SYMBOL(transport_kmap_data_sg);
2407 
2408 void transport_kunmap_data_sg(struct se_cmd *cmd)
2409 {
2410 	if (!cmd->t_data_nents) {
2411 		return;
2412 	} else if (cmd->t_data_nents == 1) {
2413 		kunmap(sg_page(cmd->t_data_sg));
2414 		return;
2415 	}
2416 
2417 	vunmap(cmd->t_data_vmap);
2418 	cmd->t_data_vmap = NULL;
2419 }
2420 EXPORT_SYMBOL(transport_kunmap_data_sg);
2421 
2422 int
2423 target_alloc_sgl(struct scatterlist **sgl, unsigned int *nents, u32 length,
2424 		 bool zero_page, bool chainable)
2425 {
2426 	struct scatterlist *sg;
2427 	struct page *page;
2428 	gfp_t zero_flag = (zero_page) ? __GFP_ZERO : 0;
2429 	unsigned int nalloc, nent;
2430 	int i = 0;
2431 
2432 	nalloc = nent = DIV_ROUND_UP(length, PAGE_SIZE);
2433 	if (chainable)
2434 		nalloc++;
2435 	sg = kmalloc_array(nalloc, sizeof(struct scatterlist), GFP_KERNEL);
2436 	if (!sg)
2437 		return -ENOMEM;
2438 
2439 	sg_init_table(sg, nalloc);
2440 
2441 	while (length) {
2442 		u32 page_len = min_t(u32, length, PAGE_SIZE);
2443 		page = alloc_page(GFP_KERNEL | zero_flag);
2444 		if (!page)
2445 			goto out;
2446 
2447 		sg_set_page(&sg[i], page, page_len, 0);
2448 		length -= page_len;
2449 		i++;
2450 	}
2451 	*sgl = sg;
2452 	*nents = nent;
2453 	return 0;
2454 
2455 out:
2456 	while (i > 0) {
2457 		i--;
2458 		__free_page(sg_page(&sg[i]));
2459 	}
2460 	kfree(sg);
2461 	return -ENOMEM;
2462 }
2463 EXPORT_SYMBOL(target_alloc_sgl);
2464 
2465 /*
2466  * Allocate any required resources to execute the command.  For writes we
2467  * might not have the payload yet, so notify the fabric via a call to
2468  * ->write_pending instead. Otherwise place it on the execution queue.
2469  */
2470 sense_reason_t
2471 transport_generic_new_cmd(struct se_cmd *cmd)
2472 {
2473 	unsigned long flags;
2474 	int ret = 0;
2475 	bool zero_flag = !(cmd->se_cmd_flags & SCF_SCSI_DATA_CDB);
2476 
2477 	if (cmd->prot_op != TARGET_PROT_NORMAL &&
2478 	    !(cmd->se_cmd_flags & SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC)) {
2479 		ret = target_alloc_sgl(&cmd->t_prot_sg, &cmd->t_prot_nents,
2480 				       cmd->prot_length, true, false);
2481 		if (ret < 0)
2482 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2483 	}
2484 
2485 	/*
2486 	 * Determine is the TCM fabric module has already allocated physical
2487 	 * memory, and is directly calling transport_generic_map_mem_to_cmd()
2488 	 * beforehand.
2489 	 */
2490 	if (!(cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) &&
2491 	    cmd->data_length) {
2492 
2493 		if ((cmd->se_cmd_flags & SCF_BIDI) ||
2494 		    (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE)) {
2495 			u32 bidi_length;
2496 
2497 			if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE)
2498 				bidi_length = cmd->t_task_nolb *
2499 					      cmd->se_dev->dev_attrib.block_size;
2500 			else
2501 				bidi_length = cmd->data_length;
2502 
2503 			ret = target_alloc_sgl(&cmd->t_bidi_data_sg,
2504 					       &cmd->t_bidi_data_nents,
2505 					       bidi_length, zero_flag, false);
2506 			if (ret < 0)
2507 				return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2508 		}
2509 
2510 		ret = target_alloc_sgl(&cmd->t_data_sg, &cmd->t_data_nents,
2511 				       cmd->data_length, zero_flag, false);
2512 		if (ret < 0)
2513 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2514 	} else if ((cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) &&
2515 		    cmd->data_length) {
2516 		/*
2517 		 * Special case for COMPARE_AND_WRITE with fabrics
2518 		 * using SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC.
2519 		 */
2520 		u32 caw_length = cmd->t_task_nolb *
2521 				 cmd->se_dev->dev_attrib.block_size;
2522 
2523 		ret = target_alloc_sgl(&cmd->t_bidi_data_sg,
2524 				       &cmd->t_bidi_data_nents,
2525 				       caw_length, zero_flag, false);
2526 		if (ret < 0)
2527 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2528 	}
2529 	/*
2530 	 * If this command is not a write we can execute it right here,
2531 	 * for write buffers we need to notify the fabric driver first
2532 	 * and let it call back once the write buffers are ready.
2533 	 */
2534 	target_add_to_state_list(cmd);
2535 	if (cmd->data_direction != DMA_TO_DEVICE || cmd->data_length == 0) {
2536 		target_execute_cmd(cmd);
2537 		return 0;
2538 	}
2539 
2540 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2541 	cmd->t_state = TRANSPORT_WRITE_PENDING;
2542 	/*
2543 	 * Determine if frontend context caller is requesting the stopping of
2544 	 * this command for frontend exceptions.
2545 	 */
2546 	if (cmd->transport_state & CMD_T_STOP) {
2547 		pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08llx\n",
2548 			 __func__, __LINE__, cmd->tag);
2549 
2550 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2551 
2552 		complete_all(&cmd->t_transport_stop_comp);
2553 		return 0;
2554 	}
2555 	cmd->transport_state &= ~CMD_T_ACTIVE;
2556 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2557 
2558 	ret = cmd->se_tfo->write_pending(cmd);
2559 	if (ret)
2560 		goto queue_full;
2561 
2562 	return 0;
2563 
2564 queue_full:
2565 	pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n", cmd);
2566 	transport_handle_queue_full(cmd, cmd->se_dev, ret, true);
2567 	return 0;
2568 }
2569 EXPORT_SYMBOL(transport_generic_new_cmd);
2570 
2571 static void transport_write_pending_qf(struct se_cmd *cmd)
2572 {
2573 	int ret;
2574 
2575 	ret = cmd->se_tfo->write_pending(cmd);
2576 	if (ret) {
2577 		pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n",
2578 			 cmd);
2579 		transport_handle_queue_full(cmd, cmd->se_dev, ret, true);
2580 	}
2581 }
2582 
2583 static bool
2584 __transport_wait_for_tasks(struct se_cmd *, bool, bool *, bool *,
2585 			   unsigned long *flags);
2586 
2587 static void target_wait_free_cmd(struct se_cmd *cmd, bool *aborted, bool *tas)
2588 {
2589 	unsigned long flags;
2590 
2591 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2592 	__transport_wait_for_tasks(cmd, true, aborted, tas, &flags);
2593 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2594 }
2595 
2596 int transport_generic_free_cmd(struct se_cmd *cmd, int wait_for_tasks)
2597 {
2598 	int ret = 0;
2599 	bool aborted = false, tas = false;
2600 
2601 	if (!(cmd->se_cmd_flags & SCF_SE_LUN_CMD)) {
2602 		if (wait_for_tasks && (cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
2603 			target_wait_free_cmd(cmd, &aborted, &tas);
2604 
2605 		if (!aborted || tas)
2606 			ret = transport_put_cmd(cmd);
2607 	} else {
2608 		if (wait_for_tasks)
2609 			target_wait_free_cmd(cmd, &aborted, &tas);
2610 		/*
2611 		 * Handle WRITE failure case where transport_generic_new_cmd()
2612 		 * has already added se_cmd to state_list, but fabric has
2613 		 * failed command before I/O submission.
2614 		 */
2615 		if (cmd->state_active)
2616 			target_remove_from_state_list(cmd);
2617 
2618 		if (cmd->se_lun)
2619 			transport_lun_remove_cmd(cmd);
2620 
2621 		if (!aborted || tas)
2622 			ret = transport_put_cmd(cmd);
2623 	}
2624 	/*
2625 	 * If the task has been internally aborted due to TMR ABORT_TASK
2626 	 * or LUN_RESET, target_core_tmr.c is responsible for performing
2627 	 * the remaining calls to target_put_sess_cmd(), and not the
2628 	 * callers of this function.
2629 	 */
2630 	if (aborted) {
2631 		pr_debug("Detected CMD_T_ABORTED for ITT: %llu\n", cmd->tag);
2632 		wait_for_completion(&cmd->cmd_wait_comp);
2633 		cmd->se_tfo->release_cmd(cmd);
2634 		ret = 1;
2635 	}
2636 	return ret;
2637 }
2638 EXPORT_SYMBOL(transport_generic_free_cmd);
2639 
2640 /* target_get_sess_cmd - Add command to active ->sess_cmd_list
2641  * @se_cmd:	command descriptor to add
2642  * @ack_kref:	Signal that fabric will perform an ack target_put_sess_cmd()
2643  */
2644 int target_get_sess_cmd(struct se_cmd *se_cmd, bool ack_kref)
2645 {
2646 	struct se_session *se_sess = se_cmd->se_sess;
2647 	unsigned long flags;
2648 	int ret = 0;
2649 
2650 	/*
2651 	 * Add a second kref if the fabric caller is expecting to handle
2652 	 * fabric acknowledgement that requires two target_put_sess_cmd()
2653 	 * invocations before se_cmd descriptor release.
2654 	 */
2655 	if (ack_kref) {
2656 		if (!kref_get_unless_zero(&se_cmd->cmd_kref))
2657 			return -EINVAL;
2658 
2659 		se_cmd->se_cmd_flags |= SCF_ACK_KREF;
2660 	}
2661 
2662 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2663 	if (se_sess->sess_tearing_down) {
2664 		ret = -ESHUTDOWN;
2665 		goto out;
2666 	}
2667 	list_add_tail(&se_cmd->se_cmd_list, &se_sess->sess_cmd_list);
2668 out:
2669 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2670 
2671 	if (ret && ack_kref)
2672 		target_put_sess_cmd(se_cmd);
2673 
2674 	return ret;
2675 }
2676 EXPORT_SYMBOL(target_get_sess_cmd);
2677 
2678 static void target_free_cmd_mem(struct se_cmd *cmd)
2679 {
2680 	transport_free_pages(cmd);
2681 
2682 	if (cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
2683 		core_tmr_release_req(cmd->se_tmr_req);
2684 	if (cmd->t_task_cdb != cmd->__t_task_cdb)
2685 		kfree(cmd->t_task_cdb);
2686 }
2687 
2688 static void target_release_cmd_kref(struct kref *kref)
2689 {
2690 	struct se_cmd *se_cmd = container_of(kref, struct se_cmd, cmd_kref);
2691 	struct se_session *se_sess = se_cmd->se_sess;
2692 	unsigned long flags;
2693 	bool fabric_stop;
2694 
2695 	if (se_sess) {
2696 		spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2697 
2698 		spin_lock(&se_cmd->t_state_lock);
2699 		fabric_stop = (se_cmd->transport_state & CMD_T_FABRIC_STOP) &&
2700 			      (se_cmd->transport_state & CMD_T_ABORTED);
2701 		spin_unlock(&se_cmd->t_state_lock);
2702 
2703 		if (se_cmd->cmd_wait_set || fabric_stop) {
2704 			list_del_init(&se_cmd->se_cmd_list);
2705 			spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2706 			target_free_cmd_mem(se_cmd);
2707 			complete(&se_cmd->cmd_wait_comp);
2708 			return;
2709 		}
2710 		list_del_init(&se_cmd->se_cmd_list);
2711 		spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2712 	}
2713 
2714 	target_free_cmd_mem(se_cmd);
2715 	se_cmd->se_tfo->release_cmd(se_cmd);
2716 }
2717 
2718 /**
2719  * target_put_sess_cmd - decrease the command reference count
2720  * @se_cmd:	command to drop a reference from
2721  *
2722  * Returns 1 if and only if this target_put_sess_cmd() call caused the
2723  * refcount to drop to zero. Returns zero otherwise.
2724  */
2725 int target_put_sess_cmd(struct se_cmd *se_cmd)
2726 {
2727 	return kref_put(&se_cmd->cmd_kref, target_release_cmd_kref);
2728 }
2729 EXPORT_SYMBOL(target_put_sess_cmd);
2730 
2731 static const char *data_dir_name(enum dma_data_direction d)
2732 {
2733 	switch (d) {
2734 	case DMA_BIDIRECTIONAL:	return "BIDI";
2735 	case DMA_TO_DEVICE:	return "WRITE";
2736 	case DMA_FROM_DEVICE:	return "READ";
2737 	case DMA_NONE:		return "NONE";
2738 	}
2739 
2740 	return "(?)";
2741 }
2742 
2743 static const char *cmd_state_name(enum transport_state_table t)
2744 {
2745 	switch (t) {
2746 	case TRANSPORT_NO_STATE:	return "NO_STATE";
2747 	case TRANSPORT_NEW_CMD:		return "NEW_CMD";
2748 	case TRANSPORT_WRITE_PENDING:	return "WRITE_PENDING";
2749 	case TRANSPORT_PROCESSING:	return "PROCESSING";
2750 	case TRANSPORT_COMPLETE:	return "COMPLETE";
2751 	case TRANSPORT_ISTATE_PROCESSING:
2752 					return "ISTATE_PROCESSING";
2753 	case TRANSPORT_COMPLETE_QF_WP:	return "COMPLETE_QF_WP";
2754 	case TRANSPORT_COMPLETE_QF_OK:	return "COMPLETE_QF_OK";
2755 	case TRANSPORT_COMPLETE_QF_ERR:	return "COMPLETE_QF_ERR";
2756 	}
2757 
2758 	return "(?)";
2759 }
2760 
2761 static void target_append_str(char **str, const char *txt)
2762 {
2763 	char *prev = *str;
2764 
2765 	*str = *str ? kasprintf(GFP_ATOMIC, "%s,%s", *str, txt) :
2766 		kstrdup(txt, GFP_ATOMIC);
2767 	kfree(prev);
2768 }
2769 
2770 /*
2771  * Convert a transport state bitmask into a string. The caller is
2772  * responsible for freeing the returned pointer.
2773  */
2774 static char *target_ts_to_str(u32 ts)
2775 {
2776 	char *str = NULL;
2777 
2778 	if (ts & CMD_T_ABORTED)
2779 		target_append_str(&str, "aborted");
2780 	if (ts & CMD_T_ACTIVE)
2781 		target_append_str(&str, "active");
2782 	if (ts & CMD_T_COMPLETE)
2783 		target_append_str(&str, "complete");
2784 	if (ts & CMD_T_SENT)
2785 		target_append_str(&str, "sent");
2786 	if (ts & CMD_T_STOP)
2787 		target_append_str(&str, "stop");
2788 	if (ts & CMD_T_FABRIC_STOP)
2789 		target_append_str(&str, "fabric_stop");
2790 
2791 	return str;
2792 }
2793 
2794 static const char *target_tmf_name(enum tcm_tmreq_table tmf)
2795 {
2796 	switch (tmf) {
2797 	case TMR_ABORT_TASK:		return "ABORT_TASK";
2798 	case TMR_ABORT_TASK_SET:	return "ABORT_TASK_SET";
2799 	case TMR_CLEAR_ACA:		return "CLEAR_ACA";
2800 	case TMR_CLEAR_TASK_SET:	return "CLEAR_TASK_SET";
2801 	case TMR_LUN_RESET:		return "LUN_RESET";
2802 	case TMR_TARGET_WARM_RESET:	return "TARGET_WARM_RESET";
2803 	case TMR_TARGET_COLD_RESET:	return "TARGET_COLD_RESET";
2804 	case TMR_UNKNOWN:		break;
2805 	}
2806 	return "(?)";
2807 }
2808 
2809 void target_show_cmd(const char *pfx, struct se_cmd *cmd)
2810 {
2811 	char *ts_str = target_ts_to_str(cmd->transport_state);
2812 	const u8 *cdb = cmd->t_task_cdb;
2813 	struct se_tmr_req *tmf = cmd->se_tmr_req;
2814 
2815 	if (!(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)) {
2816 		pr_debug("%scmd %#02x:%#02x with tag %#llx dir %s i_state %d t_state %s len %d refcnt %d transport_state %s\n",
2817 			 pfx, cdb[0], cdb[1], cmd->tag,
2818 			 data_dir_name(cmd->data_direction),
2819 			 cmd->se_tfo->get_cmd_state(cmd),
2820 			 cmd_state_name(cmd->t_state), cmd->data_length,
2821 			 kref_read(&cmd->cmd_kref), ts_str);
2822 	} else {
2823 		pr_debug("%stmf %s with tag %#llx ref_task_tag %#llx i_state %d t_state %s refcnt %d transport_state %s\n",
2824 			 pfx, target_tmf_name(tmf->function), cmd->tag,
2825 			 tmf->ref_task_tag, cmd->se_tfo->get_cmd_state(cmd),
2826 			 cmd_state_name(cmd->t_state),
2827 			 kref_read(&cmd->cmd_kref), ts_str);
2828 	}
2829 	kfree(ts_str);
2830 }
2831 EXPORT_SYMBOL(target_show_cmd);
2832 
2833 /* target_sess_cmd_list_set_waiting - Flag all commands in
2834  *         sess_cmd_list to complete cmd_wait_comp.  Set
2835  *         sess_tearing_down so no more commands are queued.
2836  * @se_sess:	session to flag
2837  */
2838 void target_sess_cmd_list_set_waiting(struct se_session *se_sess)
2839 {
2840 	struct se_cmd *se_cmd, *tmp_cmd;
2841 	unsigned long flags;
2842 	int rc;
2843 
2844 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2845 	if (se_sess->sess_tearing_down) {
2846 		spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2847 		return;
2848 	}
2849 	se_sess->sess_tearing_down = 1;
2850 	list_splice_init(&se_sess->sess_cmd_list, &se_sess->sess_wait_list);
2851 
2852 	list_for_each_entry_safe(se_cmd, tmp_cmd,
2853 				 &se_sess->sess_wait_list, se_cmd_list) {
2854 		rc = kref_get_unless_zero(&se_cmd->cmd_kref);
2855 		if (rc) {
2856 			se_cmd->cmd_wait_set = 1;
2857 			spin_lock(&se_cmd->t_state_lock);
2858 			se_cmd->transport_state |= CMD_T_FABRIC_STOP;
2859 			spin_unlock(&se_cmd->t_state_lock);
2860 		} else
2861 			list_del_init(&se_cmd->se_cmd_list);
2862 	}
2863 
2864 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2865 }
2866 EXPORT_SYMBOL(target_sess_cmd_list_set_waiting);
2867 
2868 /* target_wait_for_sess_cmds - Wait for outstanding descriptors
2869  * @se_sess:    session to wait for active I/O
2870  */
2871 void target_wait_for_sess_cmds(struct se_session *se_sess)
2872 {
2873 	struct se_cmd *se_cmd, *tmp_cmd;
2874 	unsigned long flags;
2875 	bool tas;
2876 
2877 	list_for_each_entry_safe(se_cmd, tmp_cmd,
2878 				&se_sess->sess_wait_list, se_cmd_list) {
2879 		pr_debug("Waiting for se_cmd: %p t_state: %d, fabric state:"
2880 			" %d\n", se_cmd, se_cmd->t_state,
2881 			se_cmd->se_tfo->get_cmd_state(se_cmd));
2882 
2883 		spin_lock_irqsave(&se_cmd->t_state_lock, flags);
2884 		tas = (se_cmd->transport_state & CMD_T_TAS);
2885 		spin_unlock_irqrestore(&se_cmd->t_state_lock, flags);
2886 
2887 		if (!target_put_sess_cmd(se_cmd)) {
2888 			if (tas)
2889 				target_put_sess_cmd(se_cmd);
2890 		}
2891 
2892 		wait_for_completion(&se_cmd->cmd_wait_comp);
2893 		pr_debug("After cmd_wait_comp: se_cmd: %p t_state: %d"
2894 			" fabric state: %d\n", se_cmd, se_cmd->t_state,
2895 			se_cmd->se_tfo->get_cmd_state(se_cmd));
2896 
2897 		se_cmd->se_tfo->release_cmd(se_cmd);
2898 	}
2899 
2900 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2901 	WARN_ON(!list_empty(&se_sess->sess_cmd_list));
2902 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2903 
2904 }
2905 EXPORT_SYMBOL(target_wait_for_sess_cmds);
2906 
2907 static void target_lun_confirm(struct percpu_ref *ref)
2908 {
2909 	struct se_lun *lun = container_of(ref, struct se_lun, lun_ref);
2910 
2911 	complete(&lun->lun_ref_comp);
2912 }
2913 
2914 void transport_clear_lun_ref(struct se_lun *lun)
2915 {
2916 	/*
2917 	 * Mark the percpu-ref as DEAD, switch to atomic_t mode, drop
2918 	 * the initial reference and schedule confirm kill to be
2919 	 * executed after one full RCU grace period has completed.
2920 	 */
2921 	percpu_ref_kill_and_confirm(&lun->lun_ref, target_lun_confirm);
2922 	/*
2923 	 * The first completion waits for percpu_ref_switch_to_atomic_rcu()
2924 	 * to call target_lun_confirm after lun->lun_ref has been marked
2925 	 * as __PERCPU_REF_DEAD on all CPUs, and switches to atomic_t
2926 	 * mode so that percpu_ref_tryget_live() lookup of lun->lun_ref
2927 	 * fails for all new incoming I/O.
2928 	 */
2929 	wait_for_completion(&lun->lun_ref_comp);
2930 	/*
2931 	 * The second completion waits for percpu_ref_put_many() to
2932 	 * invoke ->release() after lun->lun_ref has switched to
2933 	 * atomic_t mode, and lun->lun_ref.count has reached zero.
2934 	 *
2935 	 * At this point all target-core lun->lun_ref references have
2936 	 * been dropped via transport_lun_remove_cmd(), and it's safe
2937 	 * to proceed with the remaining LUN shutdown.
2938 	 */
2939 	wait_for_completion(&lun->lun_shutdown_comp);
2940 }
2941 
2942 static bool
2943 __transport_wait_for_tasks(struct se_cmd *cmd, bool fabric_stop,
2944 			   bool *aborted, bool *tas, unsigned long *flags)
2945 	__releases(&cmd->t_state_lock)
2946 	__acquires(&cmd->t_state_lock)
2947 {
2948 
2949 	assert_spin_locked(&cmd->t_state_lock);
2950 	WARN_ON_ONCE(!irqs_disabled());
2951 
2952 	if (fabric_stop)
2953 		cmd->transport_state |= CMD_T_FABRIC_STOP;
2954 
2955 	if (cmd->transport_state & CMD_T_ABORTED)
2956 		*aborted = true;
2957 
2958 	if (cmd->transport_state & CMD_T_TAS)
2959 		*tas = true;
2960 
2961 	if (!(cmd->se_cmd_flags & SCF_SE_LUN_CMD) &&
2962 	    !(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
2963 		return false;
2964 
2965 	if (!(cmd->se_cmd_flags & SCF_SUPPORTED_SAM_OPCODE) &&
2966 	    !(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
2967 		return false;
2968 
2969 	if (!(cmd->transport_state & CMD_T_ACTIVE))
2970 		return false;
2971 
2972 	if (fabric_stop && *aborted)
2973 		return false;
2974 
2975 	cmd->transport_state |= CMD_T_STOP;
2976 
2977 	target_show_cmd("wait_for_tasks: Stopping ", cmd);
2978 
2979 	spin_unlock_irqrestore(&cmd->t_state_lock, *flags);
2980 
2981 	while (!wait_for_completion_timeout(&cmd->t_transport_stop_comp,
2982 					    180 * HZ))
2983 		target_show_cmd("wait for tasks: ", cmd);
2984 
2985 	spin_lock_irqsave(&cmd->t_state_lock, *flags);
2986 	cmd->transport_state &= ~(CMD_T_ACTIVE | CMD_T_STOP);
2987 
2988 	pr_debug("wait_for_tasks: Stopped wait_for_completion(&cmd->"
2989 		 "t_transport_stop_comp) for ITT: 0x%08llx\n", cmd->tag);
2990 
2991 	return true;
2992 }
2993 
2994 /**
2995  * transport_wait_for_tasks - set CMD_T_STOP and wait for t_transport_stop_comp
2996  * @cmd: command to wait on
2997  */
2998 bool transport_wait_for_tasks(struct se_cmd *cmd)
2999 {
3000 	unsigned long flags;
3001 	bool ret, aborted = false, tas = false;
3002 
3003 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3004 	ret = __transport_wait_for_tasks(cmd, false, &aborted, &tas, &flags);
3005 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3006 
3007 	return ret;
3008 }
3009 EXPORT_SYMBOL(transport_wait_for_tasks);
3010 
3011 struct sense_info {
3012 	u8 key;
3013 	u8 asc;
3014 	u8 ascq;
3015 	bool add_sector_info;
3016 };
3017 
3018 static const struct sense_info sense_info_table[] = {
3019 	[TCM_NO_SENSE] = {
3020 		.key = NOT_READY
3021 	},
3022 	[TCM_NON_EXISTENT_LUN] = {
3023 		.key = ILLEGAL_REQUEST,
3024 		.asc = 0x25 /* LOGICAL UNIT NOT SUPPORTED */
3025 	},
3026 	[TCM_UNSUPPORTED_SCSI_OPCODE] = {
3027 		.key = ILLEGAL_REQUEST,
3028 		.asc = 0x20, /* INVALID COMMAND OPERATION CODE */
3029 	},
3030 	[TCM_SECTOR_COUNT_TOO_MANY] = {
3031 		.key = ILLEGAL_REQUEST,
3032 		.asc = 0x20, /* INVALID COMMAND OPERATION CODE */
3033 	},
3034 	[TCM_UNKNOWN_MODE_PAGE] = {
3035 		.key = ILLEGAL_REQUEST,
3036 		.asc = 0x24, /* INVALID FIELD IN CDB */
3037 	},
3038 	[TCM_CHECK_CONDITION_ABORT_CMD] = {
3039 		.key = ABORTED_COMMAND,
3040 		.asc = 0x29, /* BUS DEVICE RESET FUNCTION OCCURRED */
3041 		.ascq = 0x03,
3042 	},
3043 	[TCM_INCORRECT_AMOUNT_OF_DATA] = {
3044 		.key = ABORTED_COMMAND,
3045 		.asc = 0x0c, /* WRITE ERROR */
3046 		.ascq = 0x0d, /* NOT ENOUGH UNSOLICITED DATA */
3047 	},
3048 	[TCM_INVALID_CDB_FIELD] = {
3049 		.key = ILLEGAL_REQUEST,
3050 		.asc = 0x24, /* INVALID FIELD IN CDB */
3051 	},
3052 	[TCM_INVALID_PARAMETER_LIST] = {
3053 		.key = ILLEGAL_REQUEST,
3054 		.asc = 0x26, /* INVALID FIELD IN PARAMETER LIST */
3055 	},
3056 	[TCM_TOO_MANY_TARGET_DESCS] = {
3057 		.key = ILLEGAL_REQUEST,
3058 		.asc = 0x26,
3059 		.ascq = 0x06, /* TOO MANY TARGET DESCRIPTORS */
3060 	},
3061 	[TCM_UNSUPPORTED_TARGET_DESC_TYPE_CODE] = {
3062 		.key = ILLEGAL_REQUEST,
3063 		.asc = 0x26,
3064 		.ascq = 0x07, /* UNSUPPORTED TARGET DESCRIPTOR TYPE CODE */
3065 	},
3066 	[TCM_TOO_MANY_SEGMENT_DESCS] = {
3067 		.key = ILLEGAL_REQUEST,
3068 		.asc = 0x26,
3069 		.ascq = 0x08, /* TOO MANY SEGMENT DESCRIPTORS */
3070 	},
3071 	[TCM_UNSUPPORTED_SEGMENT_DESC_TYPE_CODE] = {
3072 		.key = ILLEGAL_REQUEST,
3073 		.asc = 0x26,
3074 		.ascq = 0x09, /* UNSUPPORTED SEGMENT DESCRIPTOR TYPE CODE */
3075 	},
3076 	[TCM_PARAMETER_LIST_LENGTH_ERROR] = {
3077 		.key = ILLEGAL_REQUEST,
3078 		.asc = 0x1a, /* PARAMETER LIST LENGTH ERROR */
3079 	},
3080 	[TCM_UNEXPECTED_UNSOLICITED_DATA] = {
3081 		.key = ILLEGAL_REQUEST,
3082 		.asc = 0x0c, /* WRITE ERROR */
3083 		.ascq = 0x0c, /* UNEXPECTED_UNSOLICITED_DATA */
3084 	},
3085 	[TCM_SERVICE_CRC_ERROR] = {
3086 		.key = ABORTED_COMMAND,
3087 		.asc = 0x47, /* PROTOCOL SERVICE CRC ERROR */
3088 		.ascq = 0x05, /* N/A */
3089 	},
3090 	[TCM_SNACK_REJECTED] = {
3091 		.key = ABORTED_COMMAND,
3092 		.asc = 0x11, /* READ ERROR */
3093 		.ascq = 0x13, /* FAILED RETRANSMISSION REQUEST */
3094 	},
3095 	[TCM_WRITE_PROTECTED] = {
3096 		.key = DATA_PROTECT,
3097 		.asc = 0x27, /* WRITE PROTECTED */
3098 	},
3099 	[TCM_ADDRESS_OUT_OF_RANGE] = {
3100 		.key = ILLEGAL_REQUEST,
3101 		.asc = 0x21, /* LOGICAL BLOCK ADDRESS OUT OF RANGE */
3102 	},
3103 	[TCM_CHECK_CONDITION_UNIT_ATTENTION] = {
3104 		.key = UNIT_ATTENTION,
3105 	},
3106 	[TCM_CHECK_CONDITION_NOT_READY] = {
3107 		.key = NOT_READY,
3108 	},
3109 	[TCM_MISCOMPARE_VERIFY] = {
3110 		.key = MISCOMPARE,
3111 		.asc = 0x1d, /* MISCOMPARE DURING VERIFY OPERATION */
3112 		.ascq = 0x00,
3113 	},
3114 	[TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED] = {
3115 		.key = ABORTED_COMMAND,
3116 		.asc = 0x10,
3117 		.ascq = 0x01, /* LOGICAL BLOCK GUARD CHECK FAILED */
3118 		.add_sector_info = true,
3119 	},
3120 	[TCM_LOGICAL_BLOCK_APP_TAG_CHECK_FAILED] = {
3121 		.key = ABORTED_COMMAND,
3122 		.asc = 0x10,
3123 		.ascq = 0x02, /* LOGICAL BLOCK APPLICATION TAG CHECK FAILED */
3124 		.add_sector_info = true,
3125 	},
3126 	[TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED] = {
3127 		.key = ABORTED_COMMAND,
3128 		.asc = 0x10,
3129 		.ascq = 0x03, /* LOGICAL BLOCK REFERENCE TAG CHECK FAILED */
3130 		.add_sector_info = true,
3131 	},
3132 	[TCM_COPY_TARGET_DEVICE_NOT_REACHABLE] = {
3133 		.key = COPY_ABORTED,
3134 		.asc = 0x0d,
3135 		.ascq = 0x02, /* COPY TARGET DEVICE NOT REACHABLE */
3136 
3137 	},
3138 	[TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE] = {
3139 		/*
3140 		 * Returning ILLEGAL REQUEST would cause immediate IO errors on
3141 		 * Solaris initiators.  Returning NOT READY instead means the
3142 		 * operations will be retried a finite number of times and we
3143 		 * can survive intermittent errors.
3144 		 */
3145 		.key = NOT_READY,
3146 		.asc = 0x08, /* LOGICAL UNIT COMMUNICATION FAILURE */
3147 	},
3148 };
3149 
3150 static int translate_sense_reason(struct se_cmd *cmd, sense_reason_t reason)
3151 {
3152 	const struct sense_info *si;
3153 	u8 *buffer = cmd->sense_buffer;
3154 	int r = (__force int)reason;
3155 	u8 asc, ascq;
3156 	bool desc_format = target_sense_desc_format(cmd->se_dev);
3157 
3158 	if (r < ARRAY_SIZE(sense_info_table) && sense_info_table[r].key)
3159 		si = &sense_info_table[r];
3160 	else
3161 		si = &sense_info_table[(__force int)
3162 				       TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE];
3163 
3164 	if (reason == TCM_CHECK_CONDITION_UNIT_ATTENTION) {
3165 		core_scsi3_ua_for_check_condition(cmd, &asc, &ascq);
3166 		WARN_ON_ONCE(asc == 0);
3167 	} else if (si->asc == 0) {
3168 		WARN_ON_ONCE(cmd->scsi_asc == 0);
3169 		asc = cmd->scsi_asc;
3170 		ascq = cmd->scsi_ascq;
3171 	} else {
3172 		asc = si->asc;
3173 		ascq = si->ascq;
3174 	}
3175 
3176 	scsi_build_sense_buffer(desc_format, buffer, si->key, asc, ascq);
3177 	if (si->add_sector_info)
3178 		return scsi_set_sense_information(buffer,
3179 						  cmd->scsi_sense_length,
3180 						  cmd->bad_sector);
3181 
3182 	return 0;
3183 }
3184 
3185 int
3186 transport_send_check_condition_and_sense(struct se_cmd *cmd,
3187 		sense_reason_t reason, int from_transport)
3188 {
3189 	unsigned long flags;
3190 
3191 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3192 	if (cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION) {
3193 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3194 		return 0;
3195 	}
3196 	cmd->se_cmd_flags |= SCF_SENT_CHECK_CONDITION;
3197 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3198 
3199 	if (!from_transport) {
3200 		int rc;
3201 
3202 		cmd->se_cmd_flags |= SCF_EMULATED_TASK_SENSE;
3203 		cmd->scsi_status = SAM_STAT_CHECK_CONDITION;
3204 		cmd->scsi_sense_length  = TRANSPORT_SENSE_BUFFER;
3205 		rc = translate_sense_reason(cmd, reason);
3206 		if (rc)
3207 			return rc;
3208 	}
3209 
3210 	trace_target_cmd_complete(cmd);
3211 	return cmd->se_tfo->queue_status(cmd);
3212 }
3213 EXPORT_SYMBOL(transport_send_check_condition_and_sense);
3214 
3215 static int __transport_check_aborted_status(struct se_cmd *cmd, int send_status)
3216 	__releases(&cmd->t_state_lock)
3217 	__acquires(&cmd->t_state_lock)
3218 {
3219 	int ret;
3220 
3221 	assert_spin_locked(&cmd->t_state_lock);
3222 	WARN_ON_ONCE(!irqs_disabled());
3223 
3224 	if (!(cmd->transport_state & CMD_T_ABORTED))
3225 		return 0;
3226 	/*
3227 	 * If cmd has been aborted but either no status is to be sent or it has
3228 	 * already been sent, just return
3229 	 */
3230 	if (!send_status || !(cmd->se_cmd_flags & SCF_SEND_DELAYED_TAS)) {
3231 		if (send_status)
3232 			cmd->se_cmd_flags |= SCF_SEND_DELAYED_TAS;
3233 		return 1;
3234 	}
3235 
3236 	pr_debug("Sending delayed SAM_STAT_TASK_ABORTED status for CDB:"
3237 		" 0x%02x ITT: 0x%08llx\n", cmd->t_task_cdb[0], cmd->tag);
3238 
3239 	cmd->se_cmd_flags &= ~SCF_SEND_DELAYED_TAS;
3240 	cmd->scsi_status = SAM_STAT_TASK_ABORTED;
3241 	trace_target_cmd_complete(cmd);
3242 
3243 	spin_unlock_irq(&cmd->t_state_lock);
3244 	ret = cmd->se_tfo->queue_status(cmd);
3245 	if (ret)
3246 		transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
3247 	spin_lock_irq(&cmd->t_state_lock);
3248 
3249 	return 1;
3250 }
3251 
3252 int transport_check_aborted_status(struct se_cmd *cmd, int send_status)
3253 {
3254 	int ret;
3255 
3256 	spin_lock_irq(&cmd->t_state_lock);
3257 	ret = __transport_check_aborted_status(cmd, send_status);
3258 	spin_unlock_irq(&cmd->t_state_lock);
3259 
3260 	return ret;
3261 }
3262 EXPORT_SYMBOL(transport_check_aborted_status);
3263 
3264 void transport_send_task_abort(struct se_cmd *cmd)
3265 {
3266 	unsigned long flags;
3267 	int ret;
3268 
3269 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3270 	if (cmd->se_cmd_flags & (SCF_SENT_CHECK_CONDITION)) {
3271 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3272 		return;
3273 	}
3274 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3275 
3276 	/*
3277 	 * If there are still expected incoming fabric WRITEs, we wait
3278 	 * until until they have completed before sending a TASK_ABORTED
3279 	 * response.  This response with TASK_ABORTED status will be
3280 	 * queued back to fabric module by transport_check_aborted_status().
3281 	 */
3282 	if (cmd->data_direction == DMA_TO_DEVICE) {
3283 		if (cmd->se_tfo->write_pending_status(cmd) != 0) {
3284 			spin_lock_irqsave(&cmd->t_state_lock, flags);
3285 			if (cmd->se_cmd_flags & SCF_SEND_DELAYED_TAS) {
3286 				spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3287 				goto send_abort;
3288 			}
3289 			cmd->se_cmd_flags |= SCF_SEND_DELAYED_TAS;
3290 			spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3291 			return;
3292 		}
3293 	}
3294 send_abort:
3295 	cmd->scsi_status = SAM_STAT_TASK_ABORTED;
3296 
3297 	transport_lun_remove_cmd(cmd);
3298 
3299 	pr_debug("Setting SAM_STAT_TASK_ABORTED status for CDB: 0x%02x, ITT: 0x%08llx\n",
3300 		 cmd->t_task_cdb[0], cmd->tag);
3301 
3302 	trace_target_cmd_complete(cmd);
3303 	ret = cmd->se_tfo->queue_status(cmd);
3304 	if (ret)
3305 		transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
3306 }
3307 
3308 static void target_tmr_work(struct work_struct *work)
3309 {
3310 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
3311 	struct se_device *dev = cmd->se_dev;
3312 	struct se_tmr_req *tmr = cmd->se_tmr_req;
3313 	unsigned long flags;
3314 	int ret;
3315 
3316 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3317 	if (cmd->transport_state & CMD_T_ABORTED) {
3318 		tmr->response = TMR_FUNCTION_REJECTED;
3319 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3320 		goto check_stop;
3321 	}
3322 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3323 
3324 	switch (tmr->function) {
3325 	case TMR_ABORT_TASK:
3326 		core_tmr_abort_task(dev, tmr, cmd->se_sess);
3327 		break;
3328 	case TMR_ABORT_TASK_SET:
3329 	case TMR_CLEAR_ACA:
3330 	case TMR_CLEAR_TASK_SET:
3331 		tmr->response = TMR_TASK_MGMT_FUNCTION_NOT_SUPPORTED;
3332 		break;
3333 	case TMR_LUN_RESET:
3334 		ret = core_tmr_lun_reset(dev, tmr, NULL, NULL);
3335 		tmr->response = (!ret) ? TMR_FUNCTION_COMPLETE :
3336 					 TMR_FUNCTION_REJECTED;
3337 		if (tmr->response == TMR_FUNCTION_COMPLETE) {
3338 			target_ua_allocate_lun(cmd->se_sess->se_node_acl,
3339 					       cmd->orig_fe_lun, 0x29,
3340 					       ASCQ_29H_BUS_DEVICE_RESET_FUNCTION_OCCURRED);
3341 		}
3342 		break;
3343 	case TMR_TARGET_WARM_RESET:
3344 		tmr->response = TMR_FUNCTION_REJECTED;
3345 		break;
3346 	case TMR_TARGET_COLD_RESET:
3347 		tmr->response = TMR_FUNCTION_REJECTED;
3348 		break;
3349 	default:
3350 		pr_err("Uknown TMR function: 0x%02x.\n",
3351 				tmr->function);
3352 		tmr->response = TMR_FUNCTION_REJECTED;
3353 		break;
3354 	}
3355 
3356 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3357 	if (cmd->transport_state & CMD_T_ABORTED) {
3358 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3359 		goto check_stop;
3360 	}
3361 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3362 
3363 	cmd->se_tfo->queue_tm_rsp(cmd);
3364 
3365 check_stop:
3366 	transport_lun_remove_cmd(cmd);
3367 	transport_cmd_check_stop_to_fabric(cmd);
3368 }
3369 
3370 int transport_generic_handle_tmr(
3371 	struct se_cmd *cmd)
3372 {
3373 	unsigned long flags;
3374 	bool aborted = false;
3375 
3376 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3377 	if (cmd->transport_state & CMD_T_ABORTED) {
3378 		aborted = true;
3379 	} else {
3380 		cmd->t_state = TRANSPORT_ISTATE_PROCESSING;
3381 		cmd->transport_state |= CMD_T_ACTIVE;
3382 	}
3383 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3384 
3385 	if (aborted) {
3386 		pr_warn_ratelimited("handle_tmr caught CMD_T_ABORTED TMR %d"
3387 			"ref_tag: %llu tag: %llu\n", cmd->se_tmr_req->function,
3388 			cmd->se_tmr_req->ref_task_tag, cmd->tag);
3389 		transport_lun_remove_cmd(cmd);
3390 		transport_cmd_check_stop_to_fabric(cmd);
3391 		return 0;
3392 	}
3393 
3394 	INIT_WORK(&cmd->work, target_tmr_work);
3395 	queue_work(cmd->se_dev->tmr_wq, &cmd->work);
3396 	return 0;
3397 }
3398 EXPORT_SYMBOL(transport_generic_handle_tmr);
3399 
3400 bool
3401 target_check_wce(struct se_device *dev)
3402 {
3403 	bool wce = false;
3404 
3405 	if (dev->transport->get_write_cache)
3406 		wce = dev->transport->get_write_cache(dev);
3407 	else if (dev->dev_attrib.emulate_write_cache > 0)
3408 		wce = true;
3409 
3410 	return wce;
3411 }
3412 
3413 bool
3414 target_check_fua(struct se_device *dev)
3415 {
3416 	return target_check_wce(dev) && dev->dev_attrib.emulate_fua_write > 0;
3417 }
3418