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