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