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