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)
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 
1387 	cmd->state_active = false;
1388 }
1389 EXPORT_SYMBOL(transport_init_se_cmd);
1390 
1391 static sense_reason_t
1392 transport_check_alloc_task_attr(struct se_cmd *cmd)
1393 {
1394 	struct se_device *dev = cmd->se_dev;
1395 
1396 	/*
1397 	 * Check if SAM Task Attribute emulation is enabled for this
1398 	 * struct se_device storage object
1399 	 */
1400 	if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
1401 		return 0;
1402 
1403 	if (cmd->sam_task_attr == TCM_ACA_TAG) {
1404 		pr_debug("SAM Task Attribute ACA"
1405 			" emulation is not supported\n");
1406 		return TCM_INVALID_CDB_FIELD;
1407 	}
1408 
1409 	return 0;
1410 }
1411 
1412 sense_reason_t
1413 target_setup_cmd_from_cdb(struct se_cmd *cmd, unsigned char *cdb)
1414 {
1415 	struct se_device *dev = cmd->se_dev;
1416 	sense_reason_t ret;
1417 
1418 	/*
1419 	 * Ensure that the received CDB is less than the max (252 + 8) bytes
1420 	 * for VARIABLE_LENGTH_CMD
1421 	 */
1422 	if (scsi_command_size(cdb) > SCSI_MAX_VARLEN_CDB_SIZE) {
1423 		pr_err("Received SCSI CDB with command_size: %d that"
1424 			" exceeds SCSI_MAX_VARLEN_CDB_SIZE: %d\n",
1425 			scsi_command_size(cdb), SCSI_MAX_VARLEN_CDB_SIZE);
1426 		return TCM_INVALID_CDB_FIELD;
1427 	}
1428 	/*
1429 	 * If the received CDB is larger than TCM_MAX_COMMAND_SIZE,
1430 	 * allocate the additional extended CDB buffer now..  Otherwise
1431 	 * setup the pointer from __t_task_cdb to t_task_cdb.
1432 	 */
1433 	if (scsi_command_size(cdb) > sizeof(cmd->__t_task_cdb)) {
1434 		cmd->t_task_cdb = kzalloc(scsi_command_size(cdb),
1435 						GFP_KERNEL);
1436 		if (!cmd->t_task_cdb) {
1437 			pr_err("Unable to allocate cmd->t_task_cdb"
1438 				" %u > sizeof(cmd->__t_task_cdb): %lu ops\n",
1439 				scsi_command_size(cdb),
1440 				(unsigned long)sizeof(cmd->__t_task_cdb));
1441 			return TCM_OUT_OF_RESOURCES;
1442 		}
1443 	} else
1444 		cmd->t_task_cdb = &cmd->__t_task_cdb[0];
1445 	/*
1446 	 * Copy the original CDB into cmd->
1447 	 */
1448 	memcpy(cmd->t_task_cdb, cdb, scsi_command_size(cdb));
1449 
1450 	trace_target_sequencer_start(cmd);
1451 
1452 	ret = dev->transport->parse_cdb(cmd);
1453 	if (ret == TCM_UNSUPPORTED_SCSI_OPCODE)
1454 		pr_warn_ratelimited("%s/%s: Unsupported SCSI Opcode 0x%02x, sending CHECK_CONDITION.\n",
1455 				    cmd->se_tfo->fabric_name,
1456 				    cmd->se_sess->se_node_acl->initiatorname,
1457 				    cmd->t_task_cdb[0]);
1458 	if (ret)
1459 		return ret;
1460 
1461 	ret = transport_check_alloc_task_attr(cmd);
1462 	if (ret)
1463 		return ret;
1464 
1465 	cmd->se_cmd_flags |= SCF_SUPPORTED_SAM_OPCODE;
1466 	atomic_long_inc(&cmd->se_lun->lun_stats.cmd_pdus);
1467 	return 0;
1468 }
1469 EXPORT_SYMBOL(target_setup_cmd_from_cdb);
1470 
1471 /*
1472  * Used by fabric module frontends to queue tasks directly.
1473  * May only be used from process context.
1474  */
1475 int transport_handle_cdb_direct(
1476 	struct se_cmd *cmd)
1477 {
1478 	sense_reason_t ret;
1479 
1480 	if (!cmd->se_lun) {
1481 		dump_stack();
1482 		pr_err("cmd->se_lun is NULL\n");
1483 		return -EINVAL;
1484 	}
1485 	if (in_interrupt()) {
1486 		dump_stack();
1487 		pr_err("transport_generic_handle_cdb cannot be called"
1488 				" from interrupt context\n");
1489 		return -EINVAL;
1490 	}
1491 	/*
1492 	 * Set TRANSPORT_NEW_CMD state and CMD_T_ACTIVE to ensure that
1493 	 * outstanding descriptors are handled correctly during shutdown via
1494 	 * transport_wait_for_tasks()
1495 	 *
1496 	 * Also, we don't take cmd->t_state_lock here as we only expect
1497 	 * this to be called for initial descriptor submission.
1498 	 */
1499 	cmd->t_state = TRANSPORT_NEW_CMD;
1500 	cmd->transport_state |= CMD_T_ACTIVE;
1501 
1502 	/*
1503 	 * transport_generic_new_cmd() is already handling QUEUE_FULL,
1504 	 * so follow TRANSPORT_NEW_CMD processing thread context usage
1505 	 * and call transport_generic_request_failure() if necessary..
1506 	 */
1507 	ret = transport_generic_new_cmd(cmd);
1508 	if (ret)
1509 		transport_generic_request_failure(cmd, ret);
1510 	return 0;
1511 }
1512 EXPORT_SYMBOL(transport_handle_cdb_direct);
1513 
1514 sense_reason_t
1515 transport_generic_map_mem_to_cmd(struct se_cmd *cmd, struct scatterlist *sgl,
1516 		u32 sgl_count, struct scatterlist *sgl_bidi, u32 sgl_bidi_count)
1517 {
1518 	if (!sgl || !sgl_count)
1519 		return 0;
1520 
1521 	/*
1522 	 * Reject SCSI data overflow with map_mem_to_cmd() as incoming
1523 	 * scatterlists already have been set to follow what the fabric
1524 	 * passes for the original expected data transfer length.
1525 	 */
1526 	if (cmd->se_cmd_flags & SCF_OVERFLOW_BIT) {
1527 		pr_warn("Rejecting SCSI DATA overflow for fabric using"
1528 			" SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC\n");
1529 		return TCM_INVALID_CDB_FIELD;
1530 	}
1531 
1532 	cmd->t_data_sg = sgl;
1533 	cmd->t_data_nents = sgl_count;
1534 	cmd->t_bidi_data_sg = sgl_bidi;
1535 	cmd->t_bidi_data_nents = sgl_bidi_count;
1536 
1537 	cmd->se_cmd_flags |= SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC;
1538 	return 0;
1539 }
1540 
1541 /**
1542  * target_submit_cmd_map_sgls - lookup unpacked lun and submit uninitialized
1543  * 			 se_cmd + use pre-allocated SGL memory.
1544  *
1545  * @se_cmd: command descriptor to submit
1546  * @se_sess: associated se_sess for endpoint
1547  * @cdb: pointer to SCSI CDB
1548  * @sense: pointer to SCSI sense buffer
1549  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1550  * @data_length: fabric expected data transfer length
1551  * @task_attr: SAM task attribute
1552  * @data_dir: DMA data direction
1553  * @flags: flags for command submission from target_sc_flags_tables
1554  * @sgl: struct scatterlist memory for unidirectional mapping
1555  * @sgl_count: scatterlist count for unidirectional mapping
1556  * @sgl_bidi: struct scatterlist memory for bidirectional READ mapping
1557  * @sgl_bidi_count: scatterlist count for bidirectional READ mapping
1558  * @sgl_prot: struct scatterlist memory protection information
1559  * @sgl_prot_count: scatterlist count for protection information
1560  *
1561  * Task tags are supported if the caller has set @se_cmd->tag.
1562  *
1563  * Returns non zero to signal active I/O shutdown failure.  All other
1564  * setup exceptions will be returned as a SCSI CHECK_CONDITION response,
1565  * but still return zero here.
1566  *
1567  * This may only be called from process context, and also currently
1568  * assumes internal allocation of fabric payload buffer by target-core.
1569  */
1570 int target_submit_cmd_map_sgls(struct se_cmd *se_cmd, struct se_session *se_sess,
1571 		unsigned char *cdb, unsigned char *sense, u64 unpacked_lun,
1572 		u32 data_length, int task_attr, int data_dir, int flags,
1573 		struct scatterlist *sgl, u32 sgl_count,
1574 		struct scatterlist *sgl_bidi, u32 sgl_bidi_count,
1575 		struct scatterlist *sgl_prot, u32 sgl_prot_count)
1576 {
1577 	struct se_portal_group *se_tpg;
1578 	sense_reason_t rc;
1579 	int ret;
1580 
1581 	se_tpg = se_sess->se_tpg;
1582 	BUG_ON(!se_tpg);
1583 	BUG_ON(se_cmd->se_tfo || se_cmd->se_sess);
1584 	BUG_ON(in_interrupt());
1585 	/*
1586 	 * Initialize se_cmd for target operation.  From this point
1587 	 * exceptions are handled by sending exception status via
1588 	 * target_core_fabric_ops->queue_status() callback
1589 	 */
1590 	transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess,
1591 				data_length, data_dir, task_attr, sense);
1592 
1593 	if (flags & TARGET_SCF_USE_CPUID)
1594 		se_cmd->se_cmd_flags |= SCF_USE_CPUID;
1595 	else
1596 		se_cmd->cpuid = WORK_CPU_UNBOUND;
1597 
1598 	if (flags & TARGET_SCF_UNKNOWN_SIZE)
1599 		se_cmd->unknown_data_length = 1;
1600 	/*
1601 	 * Obtain struct se_cmd->cmd_kref reference and add new cmd to
1602 	 * se_sess->sess_cmd_list.  A second kref_get here is necessary
1603 	 * for fabrics using TARGET_SCF_ACK_KREF that expect a second
1604 	 * kref_put() to happen during fabric packet acknowledgement.
1605 	 */
1606 	ret = target_get_sess_cmd(se_cmd, flags & TARGET_SCF_ACK_KREF);
1607 	if (ret)
1608 		return ret;
1609 	/*
1610 	 * Signal bidirectional data payloads to target-core
1611 	 */
1612 	if (flags & TARGET_SCF_BIDI_OP)
1613 		se_cmd->se_cmd_flags |= SCF_BIDI;
1614 	/*
1615 	 * Locate se_lun pointer and attach it to struct se_cmd
1616 	 */
1617 	rc = transport_lookup_cmd_lun(se_cmd, unpacked_lun);
1618 	if (rc) {
1619 		transport_send_check_condition_and_sense(se_cmd, rc, 0);
1620 		target_put_sess_cmd(se_cmd);
1621 		return 0;
1622 	}
1623 
1624 	rc = target_setup_cmd_from_cdb(se_cmd, cdb);
1625 	if (rc != 0) {
1626 		transport_generic_request_failure(se_cmd, rc);
1627 		return 0;
1628 	}
1629 
1630 	/*
1631 	 * Save pointers for SGLs containing protection information,
1632 	 * if present.
1633 	 */
1634 	if (sgl_prot_count) {
1635 		se_cmd->t_prot_sg = sgl_prot;
1636 		se_cmd->t_prot_nents = sgl_prot_count;
1637 		se_cmd->se_cmd_flags |= SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC;
1638 	}
1639 
1640 	/*
1641 	 * When a non zero sgl_count has been passed perform SGL passthrough
1642 	 * mapping for pre-allocated fabric memory instead of having target
1643 	 * core perform an internal SGL allocation..
1644 	 */
1645 	if (sgl_count != 0) {
1646 		BUG_ON(!sgl);
1647 
1648 		/*
1649 		 * A work-around for tcm_loop as some userspace code via
1650 		 * scsi-generic do not memset their associated read buffers,
1651 		 * so go ahead and do that here for type non-data CDBs.  Also
1652 		 * note that this is currently guaranteed to be a single SGL
1653 		 * for this case by target core in target_setup_cmd_from_cdb()
1654 		 * -> transport_generic_cmd_sequencer().
1655 		 */
1656 		if (!(se_cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) &&
1657 		     se_cmd->data_direction == DMA_FROM_DEVICE) {
1658 			unsigned char *buf = NULL;
1659 
1660 			if (sgl)
1661 				buf = kmap(sg_page(sgl)) + sgl->offset;
1662 
1663 			if (buf) {
1664 				memset(buf, 0, sgl->length);
1665 				kunmap(sg_page(sgl));
1666 			}
1667 		}
1668 
1669 		rc = transport_generic_map_mem_to_cmd(se_cmd, sgl, sgl_count,
1670 				sgl_bidi, sgl_bidi_count);
1671 		if (rc != 0) {
1672 			transport_generic_request_failure(se_cmd, rc);
1673 			return 0;
1674 		}
1675 	}
1676 
1677 	/*
1678 	 * Check if we need to delay processing because of ALUA
1679 	 * Active/NonOptimized primary access state..
1680 	 */
1681 	core_alua_check_nonop_delay(se_cmd);
1682 
1683 	transport_handle_cdb_direct(se_cmd);
1684 	return 0;
1685 }
1686 EXPORT_SYMBOL(target_submit_cmd_map_sgls);
1687 
1688 /**
1689  * target_submit_cmd - lookup unpacked lun and submit uninitialized se_cmd
1690  *
1691  * @se_cmd: command descriptor to submit
1692  * @se_sess: associated se_sess for endpoint
1693  * @cdb: pointer to SCSI CDB
1694  * @sense: pointer to SCSI sense buffer
1695  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1696  * @data_length: fabric expected data transfer length
1697  * @task_attr: SAM task attribute
1698  * @data_dir: DMA data direction
1699  * @flags: flags for command submission from target_sc_flags_tables
1700  *
1701  * Task tags are supported if the caller has set @se_cmd->tag.
1702  *
1703  * Returns non zero to signal active I/O shutdown failure.  All other
1704  * setup exceptions will be returned as a SCSI CHECK_CONDITION response,
1705  * but still return zero here.
1706  *
1707  * This may only be called from process context, and also currently
1708  * assumes internal allocation of fabric payload buffer by target-core.
1709  *
1710  * It also assumes interal target core SGL memory allocation.
1711  */
1712 int target_submit_cmd(struct se_cmd *se_cmd, struct se_session *se_sess,
1713 		unsigned char *cdb, unsigned char *sense, u64 unpacked_lun,
1714 		u32 data_length, int task_attr, int data_dir, int flags)
1715 {
1716 	return target_submit_cmd_map_sgls(se_cmd, se_sess, cdb, sense,
1717 			unpacked_lun, data_length, task_attr, data_dir,
1718 			flags, NULL, 0, NULL, 0, NULL, 0);
1719 }
1720 EXPORT_SYMBOL(target_submit_cmd);
1721 
1722 static void target_complete_tmr_failure(struct work_struct *work)
1723 {
1724 	struct se_cmd *se_cmd = container_of(work, struct se_cmd, work);
1725 
1726 	se_cmd->se_tmr_req->response = TMR_LUN_DOES_NOT_EXIST;
1727 	se_cmd->se_tfo->queue_tm_rsp(se_cmd);
1728 
1729 	transport_lun_remove_cmd(se_cmd);
1730 	transport_cmd_check_stop_to_fabric(se_cmd);
1731 }
1732 
1733 static bool target_lookup_lun_from_tag(struct se_session *se_sess, u64 tag,
1734 				       u64 *unpacked_lun)
1735 {
1736 	struct se_cmd *se_cmd;
1737 	unsigned long flags;
1738 	bool ret = false;
1739 
1740 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
1741 	list_for_each_entry(se_cmd, &se_sess->sess_cmd_list, se_cmd_list) {
1742 		if (se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
1743 			continue;
1744 
1745 		if (se_cmd->tag == tag) {
1746 			*unpacked_lun = se_cmd->orig_fe_lun;
1747 			ret = true;
1748 			break;
1749 		}
1750 	}
1751 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
1752 
1753 	return ret;
1754 }
1755 
1756 /**
1757  * target_submit_tmr - lookup unpacked lun and submit uninitialized se_cmd
1758  *                     for TMR CDBs
1759  *
1760  * @se_cmd: command descriptor to submit
1761  * @se_sess: associated se_sess for endpoint
1762  * @sense: pointer to SCSI sense buffer
1763  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1764  * @fabric_tmr_ptr: fabric context for TMR req
1765  * @tm_type: Type of TM request
1766  * @gfp: gfp type for caller
1767  * @tag: referenced task tag for TMR_ABORT_TASK
1768  * @flags: submit cmd flags
1769  *
1770  * Callable from all contexts.
1771  **/
1772 
1773 int target_submit_tmr(struct se_cmd *se_cmd, struct se_session *se_sess,
1774 		unsigned char *sense, u64 unpacked_lun,
1775 		void *fabric_tmr_ptr, unsigned char tm_type,
1776 		gfp_t gfp, u64 tag, int flags)
1777 {
1778 	struct se_portal_group *se_tpg;
1779 	int ret;
1780 
1781 	se_tpg = se_sess->se_tpg;
1782 	BUG_ON(!se_tpg);
1783 
1784 	transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess,
1785 			      0, DMA_NONE, TCM_SIMPLE_TAG, sense);
1786 	/*
1787 	 * FIXME: Currently expect caller to handle se_cmd->se_tmr_req
1788 	 * allocation failure.
1789 	 */
1790 	ret = core_tmr_alloc_req(se_cmd, fabric_tmr_ptr, tm_type, gfp);
1791 	if (ret < 0)
1792 		return -ENOMEM;
1793 
1794 	if (tm_type == TMR_ABORT_TASK)
1795 		se_cmd->se_tmr_req->ref_task_tag = tag;
1796 
1797 	/* See target_submit_cmd for commentary */
1798 	ret = target_get_sess_cmd(se_cmd, flags & TARGET_SCF_ACK_KREF);
1799 	if (ret) {
1800 		core_tmr_release_req(se_cmd->se_tmr_req);
1801 		return ret;
1802 	}
1803 	/*
1804 	 * If this is ABORT_TASK with no explicit fabric provided LUN,
1805 	 * go ahead and search active session tags for a match to figure
1806 	 * out unpacked_lun for the original se_cmd.
1807 	 */
1808 	if (tm_type == TMR_ABORT_TASK && (flags & TARGET_SCF_LOOKUP_LUN_FROM_TAG)) {
1809 		if (!target_lookup_lun_from_tag(se_sess, tag, &unpacked_lun))
1810 			goto failure;
1811 	}
1812 
1813 	ret = transport_lookup_tmr_lun(se_cmd, unpacked_lun);
1814 	if (ret)
1815 		goto failure;
1816 
1817 	transport_generic_handle_tmr(se_cmd);
1818 	return 0;
1819 
1820 	/*
1821 	 * For callback during failure handling, push this work off
1822 	 * to process context with TMR_LUN_DOES_NOT_EXIST status.
1823 	 */
1824 failure:
1825 	INIT_WORK(&se_cmd->work, target_complete_tmr_failure);
1826 	schedule_work(&se_cmd->work);
1827 	return 0;
1828 }
1829 EXPORT_SYMBOL(target_submit_tmr);
1830 
1831 /*
1832  * Handle SAM-esque emulation for generic transport request failures.
1833  */
1834 void transport_generic_request_failure(struct se_cmd *cmd,
1835 		sense_reason_t sense_reason)
1836 {
1837 	int ret = 0, post_ret;
1838 
1839 	pr_debug("-----[ Storage Engine Exception; sense_reason %d\n",
1840 		 sense_reason);
1841 	target_show_cmd("-----[ ", cmd);
1842 
1843 	/*
1844 	 * For SAM Task Attribute emulation for failed struct se_cmd
1845 	 */
1846 	transport_complete_task_attr(cmd);
1847 
1848 	if (cmd->transport_complete_callback)
1849 		cmd->transport_complete_callback(cmd, false, &post_ret);
1850 
1851 	if (cmd->transport_state & CMD_T_ABORTED) {
1852 		INIT_WORK(&cmd->work, target_abort_work);
1853 		queue_work(target_completion_wq, &cmd->work);
1854 		return;
1855 	}
1856 
1857 	switch (sense_reason) {
1858 	case TCM_NON_EXISTENT_LUN:
1859 	case TCM_UNSUPPORTED_SCSI_OPCODE:
1860 	case TCM_INVALID_CDB_FIELD:
1861 	case TCM_INVALID_PARAMETER_LIST:
1862 	case TCM_PARAMETER_LIST_LENGTH_ERROR:
1863 	case TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE:
1864 	case TCM_UNKNOWN_MODE_PAGE:
1865 	case TCM_WRITE_PROTECTED:
1866 	case TCM_ADDRESS_OUT_OF_RANGE:
1867 	case TCM_CHECK_CONDITION_ABORT_CMD:
1868 	case TCM_CHECK_CONDITION_UNIT_ATTENTION:
1869 	case TCM_CHECK_CONDITION_NOT_READY:
1870 	case TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED:
1871 	case TCM_LOGICAL_BLOCK_APP_TAG_CHECK_FAILED:
1872 	case TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED:
1873 	case TCM_COPY_TARGET_DEVICE_NOT_REACHABLE:
1874 	case TCM_TOO_MANY_TARGET_DESCS:
1875 	case TCM_UNSUPPORTED_TARGET_DESC_TYPE_CODE:
1876 	case TCM_TOO_MANY_SEGMENT_DESCS:
1877 	case TCM_UNSUPPORTED_SEGMENT_DESC_TYPE_CODE:
1878 		break;
1879 	case TCM_OUT_OF_RESOURCES:
1880 		cmd->scsi_status = SAM_STAT_TASK_SET_FULL;
1881 		goto queue_status;
1882 	case TCM_LUN_BUSY:
1883 		cmd->scsi_status = SAM_STAT_BUSY;
1884 		goto queue_status;
1885 	case TCM_RESERVATION_CONFLICT:
1886 		/*
1887 		 * No SENSE Data payload for this case, set SCSI Status
1888 		 * and queue the response to $FABRIC_MOD.
1889 		 *
1890 		 * Uses linux/include/scsi/scsi.h SAM status codes defs
1891 		 */
1892 		cmd->scsi_status = SAM_STAT_RESERVATION_CONFLICT;
1893 		/*
1894 		 * For UA Interlock Code 11b, a RESERVATION CONFLICT will
1895 		 * establish a UNIT ATTENTION with PREVIOUS RESERVATION
1896 		 * CONFLICT STATUS.
1897 		 *
1898 		 * See spc4r17, section 7.4.6 Control Mode Page, Table 349
1899 		 */
1900 		if (cmd->se_sess &&
1901 		    cmd->se_dev->dev_attrib.emulate_ua_intlck_ctrl
1902 					== TARGET_UA_INTLCK_CTRL_ESTABLISH_UA) {
1903 			target_ua_allocate_lun(cmd->se_sess->se_node_acl,
1904 					       cmd->orig_fe_lun, 0x2C,
1905 					ASCQ_2CH_PREVIOUS_RESERVATION_CONFLICT_STATUS);
1906 		}
1907 
1908 		goto queue_status;
1909 	default:
1910 		pr_err("Unknown transport error for CDB 0x%02x: %d\n",
1911 			cmd->t_task_cdb[0], sense_reason);
1912 		sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
1913 		break;
1914 	}
1915 
1916 	ret = transport_send_check_condition_and_sense(cmd, sense_reason, 0);
1917 	if (ret)
1918 		goto queue_full;
1919 
1920 check_stop:
1921 	transport_lun_remove_cmd(cmd);
1922 	transport_cmd_check_stop_to_fabric(cmd);
1923 	return;
1924 
1925 queue_status:
1926 	trace_target_cmd_complete(cmd);
1927 	ret = cmd->se_tfo->queue_status(cmd);
1928 	if (!ret)
1929 		goto check_stop;
1930 queue_full:
1931 	transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
1932 }
1933 EXPORT_SYMBOL(transport_generic_request_failure);
1934 
1935 void __target_execute_cmd(struct se_cmd *cmd, bool do_checks)
1936 {
1937 	sense_reason_t ret;
1938 
1939 	if (!cmd->execute_cmd) {
1940 		ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
1941 		goto err;
1942 	}
1943 	if (do_checks) {
1944 		/*
1945 		 * Check for an existing UNIT ATTENTION condition after
1946 		 * target_handle_task_attr() has done SAM task attr
1947 		 * checking, and possibly have already defered execution
1948 		 * out to target_restart_delayed_cmds() context.
1949 		 */
1950 		ret = target_scsi3_ua_check(cmd);
1951 		if (ret)
1952 			goto err;
1953 
1954 		ret = target_alua_state_check(cmd);
1955 		if (ret)
1956 			goto err;
1957 
1958 		ret = target_check_reservation(cmd);
1959 		if (ret) {
1960 			cmd->scsi_status = SAM_STAT_RESERVATION_CONFLICT;
1961 			goto err;
1962 		}
1963 	}
1964 
1965 	ret = cmd->execute_cmd(cmd);
1966 	if (!ret)
1967 		return;
1968 err:
1969 	spin_lock_irq(&cmd->t_state_lock);
1970 	cmd->transport_state &= ~CMD_T_SENT;
1971 	spin_unlock_irq(&cmd->t_state_lock);
1972 
1973 	transport_generic_request_failure(cmd, ret);
1974 }
1975 
1976 static int target_write_prot_action(struct se_cmd *cmd)
1977 {
1978 	u32 sectors;
1979 	/*
1980 	 * Perform WRITE_INSERT of PI using software emulation when backend
1981 	 * device has PI enabled, if the transport has not already generated
1982 	 * PI using hardware WRITE_INSERT offload.
1983 	 */
1984 	switch (cmd->prot_op) {
1985 	case TARGET_PROT_DOUT_INSERT:
1986 		if (!(cmd->se_sess->sup_prot_ops & TARGET_PROT_DOUT_INSERT))
1987 			sbc_dif_generate(cmd);
1988 		break;
1989 	case TARGET_PROT_DOUT_STRIP:
1990 		if (cmd->se_sess->sup_prot_ops & TARGET_PROT_DOUT_STRIP)
1991 			break;
1992 
1993 		sectors = cmd->data_length >> ilog2(cmd->se_dev->dev_attrib.block_size);
1994 		cmd->pi_err = sbc_dif_verify(cmd, cmd->t_task_lba,
1995 					     sectors, 0, cmd->t_prot_sg, 0);
1996 		if (unlikely(cmd->pi_err)) {
1997 			spin_lock_irq(&cmd->t_state_lock);
1998 			cmd->transport_state &= ~CMD_T_SENT;
1999 			spin_unlock_irq(&cmd->t_state_lock);
2000 			transport_generic_request_failure(cmd, cmd->pi_err);
2001 			return -1;
2002 		}
2003 		break;
2004 	default:
2005 		break;
2006 	}
2007 
2008 	return 0;
2009 }
2010 
2011 static bool target_handle_task_attr(struct se_cmd *cmd)
2012 {
2013 	struct se_device *dev = cmd->se_dev;
2014 
2015 	if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
2016 		return false;
2017 
2018 	cmd->se_cmd_flags |= SCF_TASK_ATTR_SET;
2019 
2020 	/*
2021 	 * Check for the existence of HEAD_OF_QUEUE, and if true return 1
2022 	 * to allow the passed struct se_cmd list of tasks to the front of the list.
2023 	 */
2024 	switch (cmd->sam_task_attr) {
2025 	case TCM_HEAD_TAG:
2026 		pr_debug("Added HEAD_OF_QUEUE for CDB: 0x%02x\n",
2027 			 cmd->t_task_cdb[0]);
2028 		return false;
2029 	case TCM_ORDERED_TAG:
2030 		atomic_inc_mb(&dev->dev_ordered_sync);
2031 
2032 		pr_debug("Added ORDERED for CDB: 0x%02x to ordered list\n",
2033 			 cmd->t_task_cdb[0]);
2034 
2035 		/*
2036 		 * Execute an ORDERED command if no other older commands
2037 		 * exist that need to be completed first.
2038 		 */
2039 		if (!atomic_read(&dev->simple_cmds))
2040 			return false;
2041 		break;
2042 	default:
2043 		/*
2044 		 * For SIMPLE and UNTAGGED Task Attribute commands
2045 		 */
2046 		atomic_inc_mb(&dev->simple_cmds);
2047 		break;
2048 	}
2049 
2050 	if (atomic_read(&dev->dev_ordered_sync) == 0)
2051 		return false;
2052 
2053 	spin_lock(&dev->delayed_cmd_lock);
2054 	list_add_tail(&cmd->se_delayed_node, &dev->delayed_cmd_list);
2055 	spin_unlock(&dev->delayed_cmd_lock);
2056 
2057 	pr_debug("Added CDB: 0x%02x Task Attr: 0x%02x to delayed CMD listn",
2058 		cmd->t_task_cdb[0], cmd->sam_task_attr);
2059 	return true;
2060 }
2061 
2062 void target_execute_cmd(struct se_cmd *cmd)
2063 {
2064 	/*
2065 	 * Determine if frontend context caller is requesting the stopping of
2066 	 * this command for frontend exceptions.
2067 	 *
2068 	 * If the received CDB has already been aborted stop processing it here.
2069 	 */
2070 	if (target_cmd_interrupted(cmd))
2071 		return;
2072 
2073 	spin_lock_irq(&cmd->t_state_lock);
2074 	cmd->t_state = TRANSPORT_PROCESSING;
2075 	cmd->transport_state |= CMD_T_ACTIVE | CMD_T_SENT;
2076 	spin_unlock_irq(&cmd->t_state_lock);
2077 
2078 	if (target_write_prot_action(cmd))
2079 		return;
2080 
2081 	if (target_handle_task_attr(cmd)) {
2082 		spin_lock_irq(&cmd->t_state_lock);
2083 		cmd->transport_state &= ~CMD_T_SENT;
2084 		spin_unlock_irq(&cmd->t_state_lock);
2085 		return;
2086 	}
2087 
2088 	__target_execute_cmd(cmd, true);
2089 }
2090 EXPORT_SYMBOL(target_execute_cmd);
2091 
2092 /*
2093  * Process all commands up to the last received ORDERED task attribute which
2094  * requires another blocking boundary
2095  */
2096 static void target_restart_delayed_cmds(struct se_device *dev)
2097 {
2098 	for (;;) {
2099 		struct se_cmd *cmd;
2100 
2101 		spin_lock(&dev->delayed_cmd_lock);
2102 		if (list_empty(&dev->delayed_cmd_list)) {
2103 			spin_unlock(&dev->delayed_cmd_lock);
2104 			break;
2105 		}
2106 
2107 		cmd = list_entry(dev->delayed_cmd_list.next,
2108 				 struct se_cmd, se_delayed_node);
2109 		list_del(&cmd->se_delayed_node);
2110 		spin_unlock(&dev->delayed_cmd_lock);
2111 
2112 		cmd->transport_state |= CMD_T_SENT;
2113 
2114 		__target_execute_cmd(cmd, true);
2115 
2116 		if (cmd->sam_task_attr == TCM_ORDERED_TAG)
2117 			break;
2118 	}
2119 }
2120 
2121 /*
2122  * Called from I/O completion to determine which dormant/delayed
2123  * and ordered cmds need to have their tasks added to the execution queue.
2124  */
2125 static void transport_complete_task_attr(struct se_cmd *cmd)
2126 {
2127 	struct se_device *dev = cmd->se_dev;
2128 
2129 	if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
2130 		return;
2131 
2132 	if (!(cmd->se_cmd_flags & SCF_TASK_ATTR_SET))
2133 		goto restart;
2134 
2135 	if (cmd->sam_task_attr == TCM_SIMPLE_TAG) {
2136 		atomic_dec_mb(&dev->simple_cmds);
2137 		dev->dev_cur_ordered_id++;
2138 	} else if (cmd->sam_task_attr == TCM_HEAD_TAG) {
2139 		dev->dev_cur_ordered_id++;
2140 		pr_debug("Incremented dev_cur_ordered_id: %u for HEAD_OF_QUEUE\n",
2141 			 dev->dev_cur_ordered_id);
2142 	} else if (cmd->sam_task_attr == TCM_ORDERED_TAG) {
2143 		atomic_dec_mb(&dev->dev_ordered_sync);
2144 
2145 		dev->dev_cur_ordered_id++;
2146 		pr_debug("Incremented dev_cur_ordered_id: %u for ORDERED\n",
2147 			 dev->dev_cur_ordered_id);
2148 	}
2149 	cmd->se_cmd_flags &= ~SCF_TASK_ATTR_SET;
2150 
2151 restart:
2152 	target_restart_delayed_cmds(dev);
2153 }
2154 
2155 static void transport_complete_qf(struct se_cmd *cmd)
2156 {
2157 	int ret = 0;
2158 
2159 	transport_complete_task_attr(cmd);
2160 	/*
2161 	 * If a fabric driver ->write_pending() or ->queue_data_in() callback
2162 	 * has returned neither -ENOMEM or -EAGAIN, assume it's fatal and
2163 	 * the same callbacks should not be retried.  Return CHECK_CONDITION
2164 	 * if a scsi_status is not already set.
2165 	 *
2166 	 * If a fabric driver ->queue_status() has returned non zero, always
2167 	 * keep retrying no matter what..
2168 	 */
2169 	if (cmd->t_state == TRANSPORT_COMPLETE_QF_ERR) {
2170 		if (cmd->scsi_status)
2171 			goto queue_status;
2172 
2173 		translate_sense_reason(cmd, TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE);
2174 		goto queue_status;
2175 	}
2176 
2177 	/*
2178 	 * Check if we need to send a sense buffer from
2179 	 * the struct se_cmd in question. We do NOT want
2180 	 * to take this path of the IO has been marked as
2181 	 * needing to be treated like a "normal read". This
2182 	 * is the case if it's a tape read, and either the
2183 	 * FM, EOM, or ILI bits are set, but there is no
2184 	 * sense data.
2185 	 */
2186 	if (!(cmd->se_cmd_flags & SCF_TREAT_READ_AS_NORMAL) &&
2187 	    cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE)
2188 		goto queue_status;
2189 
2190 	switch (cmd->data_direction) {
2191 	case DMA_FROM_DEVICE:
2192 		/* queue status if not treating this as a normal read */
2193 		if (cmd->scsi_status &&
2194 		    !(cmd->se_cmd_flags & SCF_TREAT_READ_AS_NORMAL))
2195 			goto queue_status;
2196 
2197 		trace_target_cmd_complete(cmd);
2198 		ret = cmd->se_tfo->queue_data_in(cmd);
2199 		break;
2200 	case DMA_TO_DEVICE:
2201 		if (cmd->se_cmd_flags & SCF_BIDI) {
2202 			ret = cmd->se_tfo->queue_data_in(cmd);
2203 			break;
2204 		}
2205 		/* fall through */
2206 	case DMA_NONE:
2207 queue_status:
2208 		trace_target_cmd_complete(cmd);
2209 		ret = cmd->se_tfo->queue_status(cmd);
2210 		break;
2211 	default:
2212 		break;
2213 	}
2214 
2215 	if (ret < 0) {
2216 		transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
2217 		return;
2218 	}
2219 	transport_lun_remove_cmd(cmd);
2220 	transport_cmd_check_stop_to_fabric(cmd);
2221 }
2222 
2223 static void transport_handle_queue_full(struct se_cmd *cmd, struct se_device *dev,
2224 					int err, bool write_pending)
2225 {
2226 	/*
2227 	 * -EAGAIN or -ENOMEM signals retry of ->write_pending() and/or
2228 	 * ->queue_data_in() callbacks from new process context.
2229 	 *
2230 	 * Otherwise for other errors, transport_complete_qf() will send
2231 	 * CHECK_CONDITION via ->queue_status() instead of attempting to
2232 	 * retry associated fabric driver data-transfer callbacks.
2233 	 */
2234 	if (err == -EAGAIN || err == -ENOMEM) {
2235 		cmd->t_state = (write_pending) ? TRANSPORT_COMPLETE_QF_WP :
2236 						 TRANSPORT_COMPLETE_QF_OK;
2237 	} else {
2238 		pr_warn_ratelimited("Got unknown fabric queue status: %d\n", err);
2239 		cmd->t_state = TRANSPORT_COMPLETE_QF_ERR;
2240 	}
2241 
2242 	spin_lock_irq(&dev->qf_cmd_lock);
2243 	list_add_tail(&cmd->se_qf_node, &cmd->se_dev->qf_cmd_list);
2244 	atomic_inc_mb(&dev->dev_qf_count);
2245 	spin_unlock_irq(&cmd->se_dev->qf_cmd_lock);
2246 
2247 	schedule_work(&cmd->se_dev->qf_work_queue);
2248 }
2249 
2250 static bool target_read_prot_action(struct se_cmd *cmd)
2251 {
2252 	switch (cmd->prot_op) {
2253 	case TARGET_PROT_DIN_STRIP:
2254 		if (!(cmd->se_sess->sup_prot_ops & TARGET_PROT_DIN_STRIP)) {
2255 			u32 sectors = cmd->data_length >>
2256 				  ilog2(cmd->se_dev->dev_attrib.block_size);
2257 
2258 			cmd->pi_err = sbc_dif_verify(cmd, cmd->t_task_lba,
2259 						     sectors, 0, cmd->t_prot_sg,
2260 						     0);
2261 			if (cmd->pi_err)
2262 				return true;
2263 		}
2264 		break;
2265 	case TARGET_PROT_DIN_INSERT:
2266 		if (cmd->se_sess->sup_prot_ops & TARGET_PROT_DIN_INSERT)
2267 			break;
2268 
2269 		sbc_dif_generate(cmd);
2270 		break;
2271 	default:
2272 		break;
2273 	}
2274 
2275 	return false;
2276 }
2277 
2278 static void target_complete_ok_work(struct work_struct *work)
2279 {
2280 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
2281 	int ret;
2282 
2283 	/*
2284 	 * Check if we need to move delayed/dormant tasks from cmds on the
2285 	 * delayed execution list after a HEAD_OF_QUEUE or ORDERED Task
2286 	 * Attribute.
2287 	 */
2288 	transport_complete_task_attr(cmd);
2289 
2290 	/*
2291 	 * Check to schedule QUEUE_FULL work, or execute an existing
2292 	 * cmd->transport_qf_callback()
2293 	 */
2294 	if (atomic_read(&cmd->se_dev->dev_qf_count) != 0)
2295 		schedule_work(&cmd->se_dev->qf_work_queue);
2296 
2297 	/*
2298 	 * Check if we need to send a sense buffer from
2299 	 * the struct se_cmd in question. We do NOT want
2300 	 * to take this path of the IO has been marked as
2301 	 * needing to be treated like a "normal read". This
2302 	 * is the case if it's a tape read, and either the
2303 	 * FM, EOM, or ILI bits are set, but there is no
2304 	 * sense data.
2305 	 */
2306 	if (!(cmd->se_cmd_flags & SCF_TREAT_READ_AS_NORMAL) &&
2307 	    cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) {
2308 		WARN_ON(!cmd->scsi_status);
2309 		ret = transport_send_check_condition_and_sense(
2310 					cmd, 0, 1);
2311 		if (ret)
2312 			goto queue_full;
2313 
2314 		transport_lun_remove_cmd(cmd);
2315 		transport_cmd_check_stop_to_fabric(cmd);
2316 		return;
2317 	}
2318 	/*
2319 	 * Check for a callback, used by amongst other things
2320 	 * XDWRITE_READ_10 and COMPARE_AND_WRITE emulation.
2321 	 */
2322 	if (cmd->transport_complete_callback) {
2323 		sense_reason_t rc;
2324 		bool caw = (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE);
2325 		bool zero_dl = !(cmd->data_length);
2326 		int post_ret = 0;
2327 
2328 		rc = cmd->transport_complete_callback(cmd, true, &post_ret);
2329 		if (!rc && !post_ret) {
2330 			if (caw && zero_dl)
2331 				goto queue_rsp;
2332 
2333 			return;
2334 		} else if (rc) {
2335 			ret = transport_send_check_condition_and_sense(cmd,
2336 						rc, 0);
2337 			if (ret)
2338 				goto queue_full;
2339 
2340 			transport_lun_remove_cmd(cmd);
2341 			transport_cmd_check_stop_to_fabric(cmd);
2342 			return;
2343 		}
2344 	}
2345 
2346 queue_rsp:
2347 	switch (cmd->data_direction) {
2348 	case DMA_FROM_DEVICE:
2349 		/*
2350 		 * if this is a READ-type IO, but SCSI status
2351 		 * is set, then skip returning data and just
2352 		 * return the status -- unless this IO is marked
2353 		 * as needing to be treated as a normal read,
2354 		 * in which case we want to go ahead and return
2355 		 * the data. This happens, for example, for tape
2356 		 * reads with the FM, EOM, or ILI bits set, with
2357 		 * no sense data.
2358 		 */
2359 		if (cmd->scsi_status &&
2360 		    !(cmd->se_cmd_flags & SCF_TREAT_READ_AS_NORMAL))
2361 			goto queue_status;
2362 
2363 		atomic_long_add(cmd->data_length,
2364 				&cmd->se_lun->lun_stats.tx_data_octets);
2365 		/*
2366 		 * Perform READ_STRIP of PI using software emulation when
2367 		 * backend had PI enabled, if the transport will not be
2368 		 * performing hardware READ_STRIP offload.
2369 		 */
2370 		if (target_read_prot_action(cmd)) {
2371 			ret = transport_send_check_condition_and_sense(cmd,
2372 						cmd->pi_err, 0);
2373 			if (ret)
2374 				goto queue_full;
2375 
2376 			transport_lun_remove_cmd(cmd);
2377 			transport_cmd_check_stop_to_fabric(cmd);
2378 			return;
2379 		}
2380 
2381 		trace_target_cmd_complete(cmd);
2382 		ret = cmd->se_tfo->queue_data_in(cmd);
2383 		if (ret)
2384 			goto queue_full;
2385 		break;
2386 	case DMA_TO_DEVICE:
2387 		atomic_long_add(cmd->data_length,
2388 				&cmd->se_lun->lun_stats.rx_data_octets);
2389 		/*
2390 		 * Check if we need to send READ payload for BIDI-COMMAND
2391 		 */
2392 		if (cmd->se_cmd_flags & SCF_BIDI) {
2393 			atomic_long_add(cmd->data_length,
2394 					&cmd->se_lun->lun_stats.tx_data_octets);
2395 			ret = cmd->se_tfo->queue_data_in(cmd);
2396 			if (ret)
2397 				goto queue_full;
2398 			break;
2399 		}
2400 		/* fall through */
2401 	case DMA_NONE:
2402 queue_status:
2403 		trace_target_cmd_complete(cmd);
2404 		ret = cmd->se_tfo->queue_status(cmd);
2405 		if (ret)
2406 			goto queue_full;
2407 		break;
2408 	default:
2409 		break;
2410 	}
2411 
2412 	transport_lun_remove_cmd(cmd);
2413 	transport_cmd_check_stop_to_fabric(cmd);
2414 	return;
2415 
2416 queue_full:
2417 	pr_debug("Handling complete_ok QUEUE_FULL: se_cmd: %p,"
2418 		" data_direction: %d\n", cmd, cmd->data_direction);
2419 
2420 	transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
2421 }
2422 
2423 void target_free_sgl(struct scatterlist *sgl, int nents)
2424 {
2425 	sgl_free_n_order(sgl, nents, 0);
2426 }
2427 EXPORT_SYMBOL(target_free_sgl);
2428 
2429 static inline void transport_reset_sgl_orig(struct se_cmd *cmd)
2430 {
2431 	/*
2432 	 * Check for saved t_data_sg that may be used for COMPARE_AND_WRITE
2433 	 * emulation, and free + reset pointers if necessary..
2434 	 */
2435 	if (!cmd->t_data_sg_orig)
2436 		return;
2437 
2438 	kfree(cmd->t_data_sg);
2439 	cmd->t_data_sg = cmd->t_data_sg_orig;
2440 	cmd->t_data_sg_orig = NULL;
2441 	cmd->t_data_nents = cmd->t_data_nents_orig;
2442 	cmd->t_data_nents_orig = 0;
2443 }
2444 
2445 static inline void transport_free_pages(struct se_cmd *cmd)
2446 {
2447 	if (!(cmd->se_cmd_flags & SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC)) {
2448 		target_free_sgl(cmd->t_prot_sg, cmd->t_prot_nents);
2449 		cmd->t_prot_sg = NULL;
2450 		cmd->t_prot_nents = 0;
2451 	}
2452 
2453 	if (cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) {
2454 		/*
2455 		 * Release special case READ buffer payload required for
2456 		 * SG_TO_MEM_NOALLOC to function with COMPARE_AND_WRITE
2457 		 */
2458 		if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) {
2459 			target_free_sgl(cmd->t_bidi_data_sg,
2460 					   cmd->t_bidi_data_nents);
2461 			cmd->t_bidi_data_sg = NULL;
2462 			cmd->t_bidi_data_nents = 0;
2463 		}
2464 		transport_reset_sgl_orig(cmd);
2465 		return;
2466 	}
2467 	transport_reset_sgl_orig(cmd);
2468 
2469 	target_free_sgl(cmd->t_data_sg, cmd->t_data_nents);
2470 	cmd->t_data_sg = NULL;
2471 	cmd->t_data_nents = 0;
2472 
2473 	target_free_sgl(cmd->t_bidi_data_sg, cmd->t_bidi_data_nents);
2474 	cmd->t_bidi_data_sg = NULL;
2475 	cmd->t_bidi_data_nents = 0;
2476 }
2477 
2478 void *transport_kmap_data_sg(struct se_cmd *cmd)
2479 {
2480 	struct scatterlist *sg = cmd->t_data_sg;
2481 	struct page **pages;
2482 	int i;
2483 
2484 	/*
2485 	 * We need to take into account a possible offset here for fabrics like
2486 	 * tcm_loop who may be using a contig buffer from the SCSI midlayer for
2487 	 * control CDBs passed as SGLs via transport_generic_map_mem_to_cmd()
2488 	 */
2489 	if (!cmd->t_data_nents)
2490 		return NULL;
2491 
2492 	BUG_ON(!sg);
2493 	if (cmd->t_data_nents == 1)
2494 		return kmap(sg_page(sg)) + sg->offset;
2495 
2496 	/* >1 page. use vmap */
2497 	pages = kmalloc_array(cmd->t_data_nents, sizeof(*pages), GFP_KERNEL);
2498 	if (!pages)
2499 		return NULL;
2500 
2501 	/* convert sg[] to pages[] */
2502 	for_each_sg(cmd->t_data_sg, sg, cmd->t_data_nents, i) {
2503 		pages[i] = sg_page(sg);
2504 	}
2505 
2506 	cmd->t_data_vmap = vmap(pages, cmd->t_data_nents,  VM_MAP, PAGE_KERNEL);
2507 	kfree(pages);
2508 	if (!cmd->t_data_vmap)
2509 		return NULL;
2510 
2511 	return cmd->t_data_vmap + cmd->t_data_sg[0].offset;
2512 }
2513 EXPORT_SYMBOL(transport_kmap_data_sg);
2514 
2515 void transport_kunmap_data_sg(struct se_cmd *cmd)
2516 {
2517 	if (!cmd->t_data_nents) {
2518 		return;
2519 	} else if (cmd->t_data_nents == 1) {
2520 		kunmap(sg_page(cmd->t_data_sg));
2521 		return;
2522 	}
2523 
2524 	vunmap(cmd->t_data_vmap);
2525 	cmd->t_data_vmap = NULL;
2526 }
2527 EXPORT_SYMBOL(transport_kunmap_data_sg);
2528 
2529 int
2530 target_alloc_sgl(struct scatterlist **sgl, unsigned int *nents, u32 length,
2531 		 bool zero_page, bool chainable)
2532 {
2533 	gfp_t gfp = GFP_KERNEL | (zero_page ? __GFP_ZERO : 0);
2534 
2535 	*sgl = sgl_alloc_order(length, 0, chainable, gfp, nents);
2536 	return *sgl ? 0 : -ENOMEM;
2537 }
2538 EXPORT_SYMBOL(target_alloc_sgl);
2539 
2540 /*
2541  * Allocate any required resources to execute the command.  For writes we
2542  * might not have the payload yet, so notify the fabric via a call to
2543  * ->write_pending instead. Otherwise place it on the execution queue.
2544  */
2545 sense_reason_t
2546 transport_generic_new_cmd(struct se_cmd *cmd)
2547 {
2548 	unsigned long flags;
2549 	int ret = 0;
2550 	bool zero_flag = !(cmd->se_cmd_flags & SCF_SCSI_DATA_CDB);
2551 
2552 	if (cmd->prot_op != TARGET_PROT_NORMAL &&
2553 	    !(cmd->se_cmd_flags & SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC)) {
2554 		ret = target_alloc_sgl(&cmd->t_prot_sg, &cmd->t_prot_nents,
2555 				       cmd->prot_length, true, false);
2556 		if (ret < 0)
2557 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2558 	}
2559 
2560 	/*
2561 	 * Determine if the TCM fabric module has already allocated physical
2562 	 * memory, and is directly calling transport_generic_map_mem_to_cmd()
2563 	 * beforehand.
2564 	 */
2565 	if (!(cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) &&
2566 	    cmd->data_length) {
2567 
2568 		if ((cmd->se_cmd_flags & SCF_BIDI) ||
2569 		    (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE)) {
2570 			u32 bidi_length;
2571 
2572 			if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE)
2573 				bidi_length = cmd->t_task_nolb *
2574 					      cmd->se_dev->dev_attrib.block_size;
2575 			else
2576 				bidi_length = cmd->data_length;
2577 
2578 			ret = target_alloc_sgl(&cmd->t_bidi_data_sg,
2579 					       &cmd->t_bidi_data_nents,
2580 					       bidi_length, zero_flag, false);
2581 			if (ret < 0)
2582 				return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2583 		}
2584 
2585 		ret = target_alloc_sgl(&cmd->t_data_sg, &cmd->t_data_nents,
2586 				       cmd->data_length, zero_flag, false);
2587 		if (ret < 0)
2588 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2589 	} else if ((cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) &&
2590 		    cmd->data_length) {
2591 		/*
2592 		 * Special case for COMPARE_AND_WRITE with fabrics
2593 		 * using SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC.
2594 		 */
2595 		u32 caw_length = cmd->t_task_nolb *
2596 				 cmd->se_dev->dev_attrib.block_size;
2597 
2598 		ret = target_alloc_sgl(&cmd->t_bidi_data_sg,
2599 				       &cmd->t_bidi_data_nents,
2600 				       caw_length, zero_flag, false);
2601 		if (ret < 0)
2602 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2603 	}
2604 	/*
2605 	 * If this command is not a write we can execute it right here,
2606 	 * for write buffers we need to notify the fabric driver first
2607 	 * and let it call back once the write buffers are ready.
2608 	 */
2609 	target_add_to_state_list(cmd);
2610 	if (cmd->data_direction != DMA_TO_DEVICE || cmd->data_length == 0) {
2611 		target_execute_cmd(cmd);
2612 		return 0;
2613 	}
2614 
2615 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2616 	cmd->t_state = TRANSPORT_WRITE_PENDING;
2617 	/*
2618 	 * Determine if frontend context caller is requesting the stopping of
2619 	 * this command for frontend exceptions.
2620 	 */
2621 	if (cmd->transport_state & CMD_T_STOP &&
2622 	    !cmd->se_tfo->write_pending_must_be_called) {
2623 		pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08llx\n",
2624 			 __func__, __LINE__, cmd->tag);
2625 
2626 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2627 
2628 		complete_all(&cmd->t_transport_stop_comp);
2629 		return 0;
2630 	}
2631 	cmd->transport_state &= ~CMD_T_ACTIVE;
2632 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2633 
2634 	ret = cmd->se_tfo->write_pending(cmd);
2635 	if (ret)
2636 		goto queue_full;
2637 
2638 	return 0;
2639 
2640 queue_full:
2641 	pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n", cmd);
2642 	transport_handle_queue_full(cmd, cmd->se_dev, ret, true);
2643 	return 0;
2644 }
2645 EXPORT_SYMBOL(transport_generic_new_cmd);
2646 
2647 static void transport_write_pending_qf(struct se_cmd *cmd)
2648 {
2649 	unsigned long flags;
2650 	int ret;
2651 	bool stop;
2652 
2653 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2654 	stop = (cmd->transport_state & (CMD_T_STOP | CMD_T_ABORTED));
2655 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2656 
2657 	if (stop) {
2658 		pr_debug("%s:%d CMD_T_STOP|CMD_T_ABORTED for ITT: 0x%08llx\n",
2659 			__func__, __LINE__, cmd->tag);
2660 		complete_all(&cmd->t_transport_stop_comp);
2661 		return;
2662 	}
2663 
2664 	ret = cmd->se_tfo->write_pending(cmd);
2665 	if (ret) {
2666 		pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n",
2667 			 cmd);
2668 		transport_handle_queue_full(cmd, cmd->se_dev, ret, true);
2669 	}
2670 }
2671 
2672 static bool
2673 __transport_wait_for_tasks(struct se_cmd *, bool, bool *, bool *,
2674 			   unsigned long *flags);
2675 
2676 static void target_wait_free_cmd(struct se_cmd *cmd, bool *aborted, bool *tas)
2677 {
2678 	unsigned long flags;
2679 
2680 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2681 	__transport_wait_for_tasks(cmd, true, aborted, tas, &flags);
2682 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2683 }
2684 
2685 /*
2686  * Call target_put_sess_cmd() and wait until target_release_cmd_kref(@cmd) has
2687  * finished.
2688  */
2689 void target_put_cmd_and_wait(struct se_cmd *cmd)
2690 {
2691 	DECLARE_COMPLETION_ONSTACK(compl);
2692 
2693 	WARN_ON_ONCE(cmd->abrt_compl);
2694 	cmd->abrt_compl = &compl;
2695 	target_put_sess_cmd(cmd);
2696 	wait_for_completion(&compl);
2697 }
2698 
2699 /*
2700  * This function is called by frontend drivers after processing of a command
2701  * has finished.
2702  *
2703  * The protocol for ensuring that either the regular frontend command
2704  * processing flow or target_handle_abort() code drops one reference is as
2705  * follows:
2706  * - Calling .queue_data_in(), .queue_status() or queue_tm_rsp() will cause
2707  *   the frontend driver to call this function synchronously or asynchronously.
2708  *   That will cause one reference to be dropped.
2709  * - During regular command processing the target core sets CMD_T_COMPLETE
2710  *   before invoking one of the .queue_*() functions.
2711  * - The code that aborts commands skips commands and TMFs for which
2712  *   CMD_T_COMPLETE has been set.
2713  * - CMD_T_ABORTED is set atomically after the CMD_T_COMPLETE check for
2714  *   commands that will be aborted.
2715  * - If the CMD_T_ABORTED flag is set but CMD_T_TAS has not been set
2716  *   transport_generic_free_cmd() skips its call to target_put_sess_cmd().
2717  * - For aborted commands for which CMD_T_TAS has been set .queue_status() will
2718  *   be called and will drop a reference.
2719  * - For aborted commands for which CMD_T_TAS has not been set .aborted_task()
2720  *   will be called. target_handle_abort() will drop the final reference.
2721  */
2722 int transport_generic_free_cmd(struct se_cmd *cmd, int wait_for_tasks)
2723 {
2724 	DECLARE_COMPLETION_ONSTACK(compl);
2725 	int ret = 0;
2726 	bool aborted = false, tas = false;
2727 
2728 	if (wait_for_tasks)
2729 		target_wait_free_cmd(cmd, &aborted, &tas);
2730 
2731 	if (cmd->se_cmd_flags & SCF_SE_LUN_CMD) {
2732 		/*
2733 		 * Handle WRITE failure case where transport_generic_new_cmd()
2734 		 * has already added se_cmd to state_list, but fabric has
2735 		 * failed command before I/O submission.
2736 		 */
2737 		if (cmd->state_active)
2738 			target_remove_from_state_list(cmd);
2739 
2740 		if (cmd->se_lun)
2741 			transport_lun_remove_cmd(cmd);
2742 	}
2743 	if (aborted)
2744 		cmd->free_compl = &compl;
2745 	ret = target_put_sess_cmd(cmd);
2746 	if (aborted) {
2747 		pr_debug("Detected CMD_T_ABORTED for ITT: %llu\n", cmd->tag);
2748 		wait_for_completion(&compl);
2749 		ret = 1;
2750 	}
2751 	return ret;
2752 }
2753 EXPORT_SYMBOL(transport_generic_free_cmd);
2754 
2755 /**
2756  * target_get_sess_cmd - Add command to active ->sess_cmd_list
2757  * @se_cmd:	command descriptor to add
2758  * @ack_kref:	Signal that fabric will perform an ack target_put_sess_cmd()
2759  */
2760 int target_get_sess_cmd(struct se_cmd *se_cmd, bool ack_kref)
2761 {
2762 	struct se_session *se_sess = se_cmd->se_sess;
2763 	unsigned long flags;
2764 	int ret = 0;
2765 
2766 	/*
2767 	 * Add a second kref if the fabric caller is expecting to handle
2768 	 * fabric acknowledgement that requires two target_put_sess_cmd()
2769 	 * invocations before se_cmd descriptor release.
2770 	 */
2771 	if (ack_kref) {
2772 		if (!kref_get_unless_zero(&se_cmd->cmd_kref))
2773 			return -EINVAL;
2774 
2775 		se_cmd->se_cmd_flags |= SCF_ACK_KREF;
2776 	}
2777 
2778 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2779 	if (se_sess->sess_tearing_down) {
2780 		ret = -ESHUTDOWN;
2781 		goto out;
2782 	}
2783 	list_add_tail(&se_cmd->se_cmd_list, &se_sess->sess_cmd_list);
2784 	percpu_ref_get(&se_sess->cmd_count);
2785 out:
2786 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2787 
2788 	if (ret && ack_kref)
2789 		target_put_sess_cmd(se_cmd);
2790 
2791 	return ret;
2792 }
2793 EXPORT_SYMBOL(target_get_sess_cmd);
2794 
2795 static void target_free_cmd_mem(struct se_cmd *cmd)
2796 {
2797 	transport_free_pages(cmd);
2798 
2799 	if (cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
2800 		core_tmr_release_req(cmd->se_tmr_req);
2801 	if (cmd->t_task_cdb != cmd->__t_task_cdb)
2802 		kfree(cmd->t_task_cdb);
2803 }
2804 
2805 static void target_release_cmd_kref(struct kref *kref)
2806 {
2807 	struct se_cmd *se_cmd = container_of(kref, struct se_cmd, cmd_kref);
2808 	struct se_session *se_sess = se_cmd->se_sess;
2809 	struct completion *free_compl = se_cmd->free_compl;
2810 	struct completion *abrt_compl = se_cmd->abrt_compl;
2811 	unsigned long flags;
2812 
2813 	if (se_sess) {
2814 		spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2815 		list_del_init(&se_cmd->se_cmd_list);
2816 		spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2817 	}
2818 
2819 	target_free_cmd_mem(se_cmd);
2820 	se_cmd->se_tfo->release_cmd(se_cmd);
2821 	if (free_compl)
2822 		complete(free_compl);
2823 	if (abrt_compl)
2824 		complete(abrt_compl);
2825 
2826 	percpu_ref_put(&se_sess->cmd_count);
2827 }
2828 
2829 /**
2830  * target_put_sess_cmd - decrease the command reference count
2831  * @se_cmd:	command to drop a reference from
2832  *
2833  * Returns 1 if and only if this target_put_sess_cmd() call caused the
2834  * refcount to drop to zero. Returns zero otherwise.
2835  */
2836 int target_put_sess_cmd(struct se_cmd *se_cmd)
2837 {
2838 	return kref_put(&se_cmd->cmd_kref, target_release_cmd_kref);
2839 }
2840 EXPORT_SYMBOL(target_put_sess_cmd);
2841 
2842 static const char *data_dir_name(enum dma_data_direction d)
2843 {
2844 	switch (d) {
2845 	case DMA_BIDIRECTIONAL:	return "BIDI";
2846 	case DMA_TO_DEVICE:	return "WRITE";
2847 	case DMA_FROM_DEVICE:	return "READ";
2848 	case DMA_NONE:		return "NONE";
2849 	}
2850 
2851 	return "(?)";
2852 }
2853 
2854 static const char *cmd_state_name(enum transport_state_table t)
2855 {
2856 	switch (t) {
2857 	case TRANSPORT_NO_STATE:	return "NO_STATE";
2858 	case TRANSPORT_NEW_CMD:		return "NEW_CMD";
2859 	case TRANSPORT_WRITE_PENDING:	return "WRITE_PENDING";
2860 	case TRANSPORT_PROCESSING:	return "PROCESSING";
2861 	case TRANSPORT_COMPLETE:	return "COMPLETE";
2862 	case TRANSPORT_ISTATE_PROCESSING:
2863 					return "ISTATE_PROCESSING";
2864 	case TRANSPORT_COMPLETE_QF_WP:	return "COMPLETE_QF_WP";
2865 	case TRANSPORT_COMPLETE_QF_OK:	return "COMPLETE_QF_OK";
2866 	case TRANSPORT_COMPLETE_QF_ERR:	return "COMPLETE_QF_ERR";
2867 	}
2868 
2869 	return "(?)";
2870 }
2871 
2872 static void target_append_str(char **str, const char *txt)
2873 {
2874 	char *prev = *str;
2875 
2876 	*str = *str ? kasprintf(GFP_ATOMIC, "%s,%s", *str, txt) :
2877 		kstrdup(txt, GFP_ATOMIC);
2878 	kfree(prev);
2879 }
2880 
2881 /*
2882  * Convert a transport state bitmask into a string. The caller is
2883  * responsible for freeing the returned pointer.
2884  */
2885 static char *target_ts_to_str(u32 ts)
2886 {
2887 	char *str = NULL;
2888 
2889 	if (ts & CMD_T_ABORTED)
2890 		target_append_str(&str, "aborted");
2891 	if (ts & CMD_T_ACTIVE)
2892 		target_append_str(&str, "active");
2893 	if (ts & CMD_T_COMPLETE)
2894 		target_append_str(&str, "complete");
2895 	if (ts & CMD_T_SENT)
2896 		target_append_str(&str, "sent");
2897 	if (ts & CMD_T_STOP)
2898 		target_append_str(&str, "stop");
2899 	if (ts & CMD_T_FABRIC_STOP)
2900 		target_append_str(&str, "fabric_stop");
2901 
2902 	return str;
2903 }
2904 
2905 static const char *target_tmf_name(enum tcm_tmreq_table tmf)
2906 {
2907 	switch (tmf) {
2908 	case TMR_ABORT_TASK:		return "ABORT_TASK";
2909 	case TMR_ABORT_TASK_SET:	return "ABORT_TASK_SET";
2910 	case TMR_CLEAR_ACA:		return "CLEAR_ACA";
2911 	case TMR_CLEAR_TASK_SET:	return "CLEAR_TASK_SET";
2912 	case TMR_LUN_RESET:		return "LUN_RESET";
2913 	case TMR_TARGET_WARM_RESET:	return "TARGET_WARM_RESET";
2914 	case TMR_TARGET_COLD_RESET:	return "TARGET_COLD_RESET";
2915 	case TMR_UNKNOWN:		break;
2916 	}
2917 	return "(?)";
2918 }
2919 
2920 void target_show_cmd(const char *pfx, struct se_cmd *cmd)
2921 {
2922 	char *ts_str = target_ts_to_str(cmd->transport_state);
2923 	const u8 *cdb = cmd->t_task_cdb;
2924 	struct se_tmr_req *tmf = cmd->se_tmr_req;
2925 
2926 	if (!(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)) {
2927 		pr_debug("%scmd %#02x:%#02x with tag %#llx dir %s i_state %d t_state %s len %d refcnt %d transport_state %s\n",
2928 			 pfx, cdb[0], cdb[1], cmd->tag,
2929 			 data_dir_name(cmd->data_direction),
2930 			 cmd->se_tfo->get_cmd_state(cmd),
2931 			 cmd_state_name(cmd->t_state), cmd->data_length,
2932 			 kref_read(&cmd->cmd_kref), ts_str);
2933 	} else {
2934 		pr_debug("%stmf %s with tag %#llx ref_task_tag %#llx i_state %d t_state %s refcnt %d transport_state %s\n",
2935 			 pfx, target_tmf_name(tmf->function), cmd->tag,
2936 			 tmf->ref_task_tag, cmd->se_tfo->get_cmd_state(cmd),
2937 			 cmd_state_name(cmd->t_state),
2938 			 kref_read(&cmd->cmd_kref), ts_str);
2939 	}
2940 	kfree(ts_str);
2941 }
2942 EXPORT_SYMBOL(target_show_cmd);
2943 
2944 /**
2945  * target_sess_cmd_list_set_waiting - Set sess_tearing_down so no new commands are queued.
2946  * @se_sess:	session to flag
2947  */
2948 void target_sess_cmd_list_set_waiting(struct se_session *se_sess)
2949 {
2950 	unsigned long flags;
2951 
2952 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2953 	se_sess->sess_tearing_down = 1;
2954 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2955 
2956 	percpu_ref_kill(&se_sess->cmd_count);
2957 }
2958 EXPORT_SYMBOL(target_sess_cmd_list_set_waiting);
2959 
2960 /**
2961  * target_wait_for_sess_cmds - Wait for outstanding commands
2962  * @se_sess:    session to wait for active I/O
2963  */
2964 void target_wait_for_sess_cmds(struct se_session *se_sess)
2965 {
2966 	struct se_cmd *cmd;
2967 	int ret;
2968 
2969 	WARN_ON_ONCE(!se_sess->sess_tearing_down);
2970 
2971 	do {
2972 		ret = wait_event_timeout(se_sess->cmd_list_wq,
2973 				percpu_ref_is_zero(&se_sess->cmd_count),
2974 				180 * HZ);
2975 		list_for_each_entry(cmd, &se_sess->sess_cmd_list, se_cmd_list)
2976 			target_show_cmd("session shutdown: still waiting for ",
2977 					cmd);
2978 	} while (ret <= 0);
2979 }
2980 EXPORT_SYMBOL(target_wait_for_sess_cmds);
2981 
2982 /*
2983  * Prevent that new percpu_ref_tryget_live() calls succeed and wait until
2984  * all references to the LUN have been released. Called during LUN shutdown.
2985  */
2986 void transport_clear_lun_ref(struct se_lun *lun)
2987 {
2988 	percpu_ref_kill(&lun->lun_ref);
2989 	wait_for_completion(&lun->lun_shutdown_comp);
2990 }
2991 
2992 static bool
2993 __transport_wait_for_tasks(struct se_cmd *cmd, bool fabric_stop,
2994 			   bool *aborted, bool *tas, unsigned long *flags)
2995 	__releases(&cmd->t_state_lock)
2996 	__acquires(&cmd->t_state_lock)
2997 {
2998 
2999 	assert_spin_locked(&cmd->t_state_lock);
3000 	WARN_ON_ONCE(!irqs_disabled());
3001 
3002 	if (fabric_stop)
3003 		cmd->transport_state |= CMD_T_FABRIC_STOP;
3004 
3005 	if (cmd->transport_state & CMD_T_ABORTED)
3006 		*aborted = true;
3007 
3008 	if (cmd->transport_state & CMD_T_TAS)
3009 		*tas = true;
3010 
3011 	if (!(cmd->se_cmd_flags & SCF_SE_LUN_CMD) &&
3012 	    !(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
3013 		return false;
3014 
3015 	if (!(cmd->se_cmd_flags & SCF_SUPPORTED_SAM_OPCODE) &&
3016 	    !(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
3017 		return false;
3018 
3019 	if (!(cmd->transport_state & CMD_T_ACTIVE))
3020 		return false;
3021 
3022 	if (fabric_stop && *aborted)
3023 		return false;
3024 
3025 	cmd->transport_state |= CMD_T_STOP;
3026 
3027 	target_show_cmd("wait_for_tasks: Stopping ", cmd);
3028 
3029 	spin_unlock_irqrestore(&cmd->t_state_lock, *flags);
3030 
3031 	while (!wait_for_completion_timeout(&cmd->t_transport_stop_comp,
3032 					    180 * HZ))
3033 		target_show_cmd("wait for tasks: ", cmd);
3034 
3035 	spin_lock_irqsave(&cmd->t_state_lock, *flags);
3036 	cmd->transport_state &= ~(CMD_T_ACTIVE | CMD_T_STOP);
3037 
3038 	pr_debug("wait_for_tasks: Stopped wait_for_completion(&cmd->"
3039 		 "t_transport_stop_comp) for ITT: 0x%08llx\n", cmd->tag);
3040 
3041 	return true;
3042 }
3043 
3044 /**
3045  * transport_wait_for_tasks - set CMD_T_STOP and wait for t_transport_stop_comp
3046  * @cmd: command to wait on
3047  */
3048 bool transport_wait_for_tasks(struct se_cmd *cmd)
3049 {
3050 	unsigned long flags;
3051 	bool ret, aborted = false, tas = false;
3052 
3053 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3054 	ret = __transport_wait_for_tasks(cmd, false, &aborted, &tas, &flags);
3055 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3056 
3057 	return ret;
3058 }
3059 EXPORT_SYMBOL(transport_wait_for_tasks);
3060 
3061 struct sense_info {
3062 	u8 key;
3063 	u8 asc;
3064 	u8 ascq;
3065 	bool add_sector_info;
3066 };
3067 
3068 static const struct sense_info sense_info_table[] = {
3069 	[TCM_NO_SENSE] = {
3070 		.key = NOT_READY
3071 	},
3072 	[TCM_NON_EXISTENT_LUN] = {
3073 		.key = ILLEGAL_REQUEST,
3074 		.asc = 0x25 /* LOGICAL UNIT NOT SUPPORTED */
3075 	},
3076 	[TCM_UNSUPPORTED_SCSI_OPCODE] = {
3077 		.key = ILLEGAL_REQUEST,
3078 		.asc = 0x20, /* INVALID COMMAND OPERATION CODE */
3079 	},
3080 	[TCM_SECTOR_COUNT_TOO_MANY] = {
3081 		.key = ILLEGAL_REQUEST,
3082 		.asc = 0x20, /* INVALID COMMAND OPERATION CODE */
3083 	},
3084 	[TCM_UNKNOWN_MODE_PAGE] = {
3085 		.key = ILLEGAL_REQUEST,
3086 		.asc = 0x24, /* INVALID FIELD IN CDB */
3087 	},
3088 	[TCM_CHECK_CONDITION_ABORT_CMD] = {
3089 		.key = ABORTED_COMMAND,
3090 		.asc = 0x29, /* BUS DEVICE RESET FUNCTION OCCURRED */
3091 		.ascq = 0x03,
3092 	},
3093 	[TCM_INCORRECT_AMOUNT_OF_DATA] = {
3094 		.key = ABORTED_COMMAND,
3095 		.asc = 0x0c, /* WRITE ERROR */
3096 		.ascq = 0x0d, /* NOT ENOUGH UNSOLICITED DATA */
3097 	},
3098 	[TCM_INVALID_CDB_FIELD] = {
3099 		.key = ILLEGAL_REQUEST,
3100 		.asc = 0x24, /* INVALID FIELD IN CDB */
3101 	},
3102 	[TCM_INVALID_PARAMETER_LIST] = {
3103 		.key = ILLEGAL_REQUEST,
3104 		.asc = 0x26, /* INVALID FIELD IN PARAMETER LIST */
3105 	},
3106 	[TCM_TOO_MANY_TARGET_DESCS] = {
3107 		.key = ILLEGAL_REQUEST,
3108 		.asc = 0x26,
3109 		.ascq = 0x06, /* TOO MANY TARGET DESCRIPTORS */
3110 	},
3111 	[TCM_UNSUPPORTED_TARGET_DESC_TYPE_CODE] = {
3112 		.key = ILLEGAL_REQUEST,
3113 		.asc = 0x26,
3114 		.ascq = 0x07, /* UNSUPPORTED TARGET DESCRIPTOR TYPE CODE */
3115 	},
3116 	[TCM_TOO_MANY_SEGMENT_DESCS] = {
3117 		.key = ILLEGAL_REQUEST,
3118 		.asc = 0x26,
3119 		.ascq = 0x08, /* TOO MANY SEGMENT DESCRIPTORS */
3120 	},
3121 	[TCM_UNSUPPORTED_SEGMENT_DESC_TYPE_CODE] = {
3122 		.key = ILLEGAL_REQUEST,
3123 		.asc = 0x26,
3124 		.ascq = 0x09, /* UNSUPPORTED SEGMENT DESCRIPTOR TYPE CODE */
3125 	},
3126 	[TCM_PARAMETER_LIST_LENGTH_ERROR] = {
3127 		.key = ILLEGAL_REQUEST,
3128 		.asc = 0x1a, /* PARAMETER LIST LENGTH ERROR */
3129 	},
3130 	[TCM_UNEXPECTED_UNSOLICITED_DATA] = {
3131 		.key = ILLEGAL_REQUEST,
3132 		.asc = 0x0c, /* WRITE ERROR */
3133 		.ascq = 0x0c, /* UNEXPECTED_UNSOLICITED_DATA */
3134 	},
3135 	[TCM_SERVICE_CRC_ERROR] = {
3136 		.key = ABORTED_COMMAND,
3137 		.asc = 0x47, /* PROTOCOL SERVICE CRC ERROR */
3138 		.ascq = 0x05, /* N/A */
3139 	},
3140 	[TCM_SNACK_REJECTED] = {
3141 		.key = ABORTED_COMMAND,
3142 		.asc = 0x11, /* READ ERROR */
3143 		.ascq = 0x13, /* FAILED RETRANSMISSION REQUEST */
3144 	},
3145 	[TCM_WRITE_PROTECTED] = {
3146 		.key = DATA_PROTECT,
3147 		.asc = 0x27, /* WRITE PROTECTED */
3148 	},
3149 	[TCM_ADDRESS_OUT_OF_RANGE] = {
3150 		.key = ILLEGAL_REQUEST,
3151 		.asc = 0x21, /* LOGICAL BLOCK ADDRESS OUT OF RANGE */
3152 	},
3153 	[TCM_CHECK_CONDITION_UNIT_ATTENTION] = {
3154 		.key = UNIT_ATTENTION,
3155 	},
3156 	[TCM_CHECK_CONDITION_NOT_READY] = {
3157 		.key = NOT_READY,
3158 	},
3159 	[TCM_MISCOMPARE_VERIFY] = {
3160 		.key = MISCOMPARE,
3161 		.asc = 0x1d, /* MISCOMPARE DURING VERIFY OPERATION */
3162 		.ascq = 0x00,
3163 	},
3164 	[TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED] = {
3165 		.key = ABORTED_COMMAND,
3166 		.asc = 0x10,
3167 		.ascq = 0x01, /* LOGICAL BLOCK GUARD CHECK FAILED */
3168 		.add_sector_info = true,
3169 	},
3170 	[TCM_LOGICAL_BLOCK_APP_TAG_CHECK_FAILED] = {
3171 		.key = ABORTED_COMMAND,
3172 		.asc = 0x10,
3173 		.ascq = 0x02, /* LOGICAL BLOCK APPLICATION TAG CHECK FAILED */
3174 		.add_sector_info = true,
3175 	},
3176 	[TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED] = {
3177 		.key = ABORTED_COMMAND,
3178 		.asc = 0x10,
3179 		.ascq = 0x03, /* LOGICAL BLOCK REFERENCE TAG CHECK FAILED */
3180 		.add_sector_info = true,
3181 	},
3182 	[TCM_COPY_TARGET_DEVICE_NOT_REACHABLE] = {
3183 		.key = COPY_ABORTED,
3184 		.asc = 0x0d,
3185 		.ascq = 0x02, /* COPY TARGET DEVICE NOT REACHABLE */
3186 
3187 	},
3188 	[TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE] = {
3189 		/*
3190 		 * Returning ILLEGAL REQUEST would cause immediate IO errors on
3191 		 * Solaris initiators.  Returning NOT READY instead means the
3192 		 * operations will be retried a finite number of times and we
3193 		 * can survive intermittent errors.
3194 		 */
3195 		.key = NOT_READY,
3196 		.asc = 0x08, /* LOGICAL UNIT COMMUNICATION FAILURE */
3197 	},
3198 	[TCM_INSUFFICIENT_REGISTRATION_RESOURCES] = {
3199 		/*
3200 		 * From spc4r22 section5.7.7,5.7.8
3201 		 * If a PERSISTENT RESERVE OUT command with a REGISTER service action
3202 		 * or a REGISTER AND IGNORE EXISTING KEY service action or
3203 		 * REGISTER AND MOVE service actionis attempted,
3204 		 * but there are insufficient device server resources to complete the
3205 		 * operation, then the command shall be terminated with CHECK CONDITION
3206 		 * status, with the sense key set to ILLEGAL REQUEST,and the additonal
3207 		 * sense code set to INSUFFICIENT REGISTRATION RESOURCES.
3208 		 */
3209 		.key = ILLEGAL_REQUEST,
3210 		.asc = 0x55,
3211 		.ascq = 0x04, /* INSUFFICIENT REGISTRATION RESOURCES */
3212 	},
3213 };
3214 
3215 /**
3216  * translate_sense_reason - translate a sense reason into T10 key, asc and ascq
3217  * @cmd: SCSI command in which the resulting sense buffer or SCSI status will
3218  *   be stored.
3219  * @reason: LIO sense reason code. If this argument has the value
3220  *   TCM_CHECK_CONDITION_UNIT_ATTENTION, try to dequeue a unit attention. If
3221  *   dequeuing a unit attention fails due to multiple commands being processed
3222  *   concurrently, set the command status to BUSY.
3223  *
3224  * Return: 0 upon success or -EINVAL if the sense buffer is too small.
3225  */
3226 static void translate_sense_reason(struct se_cmd *cmd, sense_reason_t reason)
3227 {
3228 	const struct sense_info *si;
3229 	u8 *buffer = cmd->sense_buffer;
3230 	int r = (__force int)reason;
3231 	u8 key, asc, ascq;
3232 	bool desc_format = target_sense_desc_format(cmd->se_dev);
3233 
3234 	if (r < ARRAY_SIZE(sense_info_table) && sense_info_table[r].key)
3235 		si = &sense_info_table[r];
3236 	else
3237 		si = &sense_info_table[(__force int)
3238 				       TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE];
3239 
3240 	key = si->key;
3241 	if (reason == TCM_CHECK_CONDITION_UNIT_ATTENTION) {
3242 		if (!core_scsi3_ua_for_check_condition(cmd, &key, &asc,
3243 						       &ascq)) {
3244 			cmd->scsi_status = SAM_STAT_BUSY;
3245 			return;
3246 		}
3247 	} else if (si->asc == 0) {
3248 		WARN_ON_ONCE(cmd->scsi_asc == 0);
3249 		asc = cmd->scsi_asc;
3250 		ascq = cmd->scsi_ascq;
3251 	} else {
3252 		asc = si->asc;
3253 		ascq = si->ascq;
3254 	}
3255 
3256 	cmd->se_cmd_flags |= SCF_EMULATED_TASK_SENSE;
3257 	cmd->scsi_status = SAM_STAT_CHECK_CONDITION;
3258 	cmd->scsi_sense_length  = TRANSPORT_SENSE_BUFFER;
3259 	scsi_build_sense_buffer(desc_format, buffer, key, asc, ascq);
3260 	if (si->add_sector_info)
3261 		WARN_ON_ONCE(scsi_set_sense_information(buffer,
3262 							cmd->scsi_sense_length,
3263 							cmd->bad_sector) < 0);
3264 }
3265 
3266 int
3267 transport_send_check_condition_and_sense(struct se_cmd *cmd,
3268 		sense_reason_t reason, int from_transport)
3269 {
3270 	unsigned long flags;
3271 
3272 	WARN_ON_ONCE(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB);
3273 
3274 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3275 	if (cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION) {
3276 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3277 		return 0;
3278 	}
3279 	cmd->se_cmd_flags |= SCF_SENT_CHECK_CONDITION;
3280 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3281 
3282 	if (!from_transport)
3283 		translate_sense_reason(cmd, reason);
3284 
3285 	trace_target_cmd_complete(cmd);
3286 	return cmd->se_tfo->queue_status(cmd);
3287 }
3288 EXPORT_SYMBOL(transport_send_check_condition_and_sense);
3289 
3290 /**
3291  * target_send_busy - Send SCSI BUSY status back to the initiator
3292  * @cmd: SCSI command for which to send a BUSY reply.
3293  *
3294  * Note: Only call this function if target_submit_cmd*() failed.
3295  */
3296 int target_send_busy(struct se_cmd *cmd)
3297 {
3298 	WARN_ON_ONCE(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB);
3299 
3300 	cmd->scsi_status = SAM_STAT_BUSY;
3301 	trace_target_cmd_complete(cmd);
3302 	return cmd->se_tfo->queue_status(cmd);
3303 }
3304 EXPORT_SYMBOL(target_send_busy);
3305 
3306 static void target_tmr_work(struct work_struct *work)
3307 {
3308 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
3309 	struct se_device *dev = cmd->se_dev;
3310 	struct se_tmr_req *tmr = cmd->se_tmr_req;
3311 	int ret;
3312 
3313 	if (cmd->transport_state & CMD_T_ABORTED)
3314 		goto aborted;
3315 
3316 	switch (tmr->function) {
3317 	case TMR_ABORT_TASK:
3318 		core_tmr_abort_task(dev, tmr, cmd->se_sess);
3319 		break;
3320 	case TMR_ABORT_TASK_SET:
3321 	case TMR_CLEAR_ACA:
3322 	case TMR_CLEAR_TASK_SET:
3323 		tmr->response = TMR_TASK_MGMT_FUNCTION_NOT_SUPPORTED;
3324 		break;
3325 	case TMR_LUN_RESET:
3326 		ret = core_tmr_lun_reset(dev, tmr, NULL, NULL);
3327 		tmr->response = (!ret) ? TMR_FUNCTION_COMPLETE :
3328 					 TMR_FUNCTION_REJECTED;
3329 		if (tmr->response == TMR_FUNCTION_COMPLETE) {
3330 			target_ua_allocate_lun(cmd->se_sess->se_node_acl,
3331 					       cmd->orig_fe_lun, 0x29,
3332 					       ASCQ_29H_BUS_DEVICE_RESET_FUNCTION_OCCURRED);
3333 		}
3334 		break;
3335 	case TMR_TARGET_WARM_RESET:
3336 		tmr->response = TMR_FUNCTION_REJECTED;
3337 		break;
3338 	case TMR_TARGET_COLD_RESET:
3339 		tmr->response = TMR_FUNCTION_REJECTED;
3340 		break;
3341 	default:
3342 		pr_err("Unknown TMR function: 0x%02x.\n",
3343 				tmr->function);
3344 		tmr->response = TMR_FUNCTION_REJECTED;
3345 		break;
3346 	}
3347 
3348 	if (cmd->transport_state & CMD_T_ABORTED)
3349 		goto aborted;
3350 
3351 	cmd->se_tfo->queue_tm_rsp(cmd);
3352 
3353 	transport_cmd_check_stop_to_fabric(cmd);
3354 	return;
3355 
3356 aborted:
3357 	target_handle_abort(cmd);
3358 }
3359 
3360 int transport_generic_handle_tmr(
3361 	struct se_cmd *cmd)
3362 {
3363 	unsigned long flags;
3364 	bool aborted = false;
3365 
3366 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3367 	if (cmd->transport_state & CMD_T_ABORTED) {
3368 		aborted = true;
3369 	} else {
3370 		cmd->t_state = TRANSPORT_ISTATE_PROCESSING;
3371 		cmd->transport_state |= CMD_T_ACTIVE;
3372 	}
3373 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3374 
3375 	if (aborted) {
3376 		pr_warn_ratelimited("handle_tmr caught CMD_T_ABORTED TMR %d ref_tag: %llu tag: %llu\n",
3377 				    cmd->se_tmr_req->function,
3378 				    cmd->se_tmr_req->ref_task_tag, cmd->tag);
3379 		target_handle_abort(cmd);
3380 		return 0;
3381 	}
3382 
3383 	INIT_WORK(&cmd->work, target_tmr_work);
3384 	schedule_work(&cmd->work);
3385 	return 0;
3386 }
3387 EXPORT_SYMBOL(transport_generic_handle_tmr);
3388 
3389 bool
3390 target_check_wce(struct se_device *dev)
3391 {
3392 	bool wce = false;
3393 
3394 	if (dev->transport->get_write_cache)
3395 		wce = dev->transport->get_write_cache(dev);
3396 	else if (dev->dev_attrib.emulate_write_cache > 0)
3397 		wce = true;
3398 
3399 	return wce;
3400 }
3401 
3402 bool
3403 target_check_fua(struct se_device *dev)
3404 {
3405 	return target_check_wce(dev) && dev->dev_attrib.emulate_fua_write > 0;
3406 }
3407