xref: /linux/drivers/target/target_core_transport.c (revision 26fbb4c8c7c3ee9a4c3b4de555a8587b5a19154e)
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_count_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 	spin_lock_init(&se_sess->sess_cmd_lock);
232 	init_waitqueue_head(&se_sess->cmd_count_wq);
233 	init_completion(&se_sess->stop_done);
234 	atomic_set(&se_sess->stopped, 0);
235 	return percpu_ref_init(&se_sess->cmd_count,
236 			       target_release_sess_cmd_refcnt, 0, GFP_KERNEL);
237 }
238 EXPORT_SYMBOL(transport_init_session);
239 
240 void transport_uninit_session(struct se_session *se_sess)
241 {
242 	/*
243 	 * Drivers like iscsi and loop do not call target_stop_session
244 	 * during session shutdown so we have to drop the ref taken at init
245 	 * time here.
246 	 */
247 	if (!atomic_read(&se_sess->stopped))
248 		percpu_ref_put(&se_sess->cmd_count);
249 
250 	percpu_ref_exit(&se_sess->cmd_count);
251 }
252 
253 /**
254  * transport_alloc_session - allocate a session object and initialize it
255  * @sup_prot_ops: bitmask that defines which T10-PI modes are supported.
256  */
257 struct se_session *transport_alloc_session(enum target_prot_op sup_prot_ops)
258 {
259 	struct se_session *se_sess;
260 	int ret;
261 
262 	se_sess = kmem_cache_zalloc(se_sess_cache, GFP_KERNEL);
263 	if (!se_sess) {
264 		pr_err("Unable to allocate struct se_session from"
265 				" se_sess_cache\n");
266 		return ERR_PTR(-ENOMEM);
267 	}
268 	ret = transport_init_session(se_sess);
269 	if (ret < 0) {
270 		kmem_cache_free(se_sess_cache, se_sess);
271 		return ERR_PTR(ret);
272 	}
273 	se_sess->sup_prot_ops = sup_prot_ops;
274 
275 	return se_sess;
276 }
277 EXPORT_SYMBOL(transport_alloc_session);
278 
279 /**
280  * transport_alloc_session_tags - allocate target driver private data
281  * @se_sess:  Session pointer.
282  * @tag_num:  Maximum number of in-flight commands between initiator and target.
283  * @tag_size: Size in bytes of the private data a target driver associates with
284  *	      each command.
285  */
286 int transport_alloc_session_tags(struct se_session *se_sess,
287 			         unsigned int tag_num, unsigned int tag_size)
288 {
289 	int rc;
290 
291 	se_sess->sess_cmd_map = kvcalloc(tag_size, tag_num,
292 					 GFP_KERNEL | __GFP_RETRY_MAYFAIL);
293 	if (!se_sess->sess_cmd_map) {
294 		pr_err("Unable to allocate se_sess->sess_cmd_map\n");
295 		return -ENOMEM;
296 	}
297 
298 	rc = sbitmap_queue_init_node(&se_sess->sess_tag_pool, tag_num, -1,
299 			false, GFP_KERNEL, NUMA_NO_NODE);
300 	if (rc < 0) {
301 		pr_err("Unable to init se_sess->sess_tag_pool,"
302 			" tag_num: %u\n", tag_num);
303 		kvfree(se_sess->sess_cmd_map);
304 		se_sess->sess_cmd_map = NULL;
305 		return -ENOMEM;
306 	}
307 
308 	return 0;
309 }
310 EXPORT_SYMBOL(transport_alloc_session_tags);
311 
312 /**
313  * transport_init_session_tags - allocate a session and target driver private data
314  * @tag_num:  Maximum number of in-flight commands between initiator and target.
315  * @tag_size: Size in bytes of the private data a target driver associates with
316  *	      each command.
317  * @sup_prot_ops: bitmask that defines which T10-PI modes are supported.
318  */
319 static struct se_session *
320 transport_init_session_tags(unsigned int tag_num, unsigned int tag_size,
321 			    enum target_prot_op sup_prot_ops)
322 {
323 	struct se_session *se_sess;
324 	int rc;
325 
326 	if (tag_num != 0 && !tag_size) {
327 		pr_err("init_session_tags called with percpu-ida tag_num:"
328 		       " %u, but zero tag_size\n", tag_num);
329 		return ERR_PTR(-EINVAL);
330 	}
331 	if (!tag_num && tag_size) {
332 		pr_err("init_session_tags called with percpu-ida tag_size:"
333 		       " %u, but zero tag_num\n", tag_size);
334 		return ERR_PTR(-EINVAL);
335 	}
336 
337 	se_sess = transport_alloc_session(sup_prot_ops);
338 	if (IS_ERR(se_sess))
339 		return se_sess;
340 
341 	rc = transport_alloc_session_tags(se_sess, tag_num, tag_size);
342 	if (rc < 0) {
343 		transport_free_session(se_sess);
344 		return ERR_PTR(-ENOMEM);
345 	}
346 
347 	return se_sess;
348 }
349 
350 /*
351  * Called with spin_lock_irqsave(&struct se_portal_group->session_lock called.
352  */
353 void __transport_register_session(
354 	struct se_portal_group *se_tpg,
355 	struct se_node_acl *se_nacl,
356 	struct se_session *se_sess,
357 	void *fabric_sess_ptr)
358 {
359 	const struct target_core_fabric_ops *tfo = se_tpg->se_tpg_tfo;
360 	unsigned char buf[PR_REG_ISID_LEN];
361 	unsigned long flags;
362 
363 	se_sess->se_tpg = se_tpg;
364 	se_sess->fabric_sess_ptr = fabric_sess_ptr;
365 	/*
366 	 * Used by struct se_node_acl's under ConfigFS to locate active se_session-t
367 	 *
368 	 * Only set for struct se_session's that will actually be moving I/O.
369 	 * eg: *NOT* discovery sessions.
370 	 */
371 	if (se_nacl) {
372 		/*
373 		 *
374 		 * Determine if fabric allows for T10-PI feature bits exposed to
375 		 * initiators for device backends with !dev->dev_attrib.pi_prot_type.
376 		 *
377 		 * If so, then always save prot_type on a per se_node_acl node
378 		 * basis and re-instate the previous sess_prot_type to avoid
379 		 * disabling PI from below any previously initiator side
380 		 * registered LUNs.
381 		 */
382 		if (se_nacl->saved_prot_type)
383 			se_sess->sess_prot_type = se_nacl->saved_prot_type;
384 		else if (tfo->tpg_check_prot_fabric_only)
385 			se_sess->sess_prot_type = se_nacl->saved_prot_type =
386 					tfo->tpg_check_prot_fabric_only(se_tpg);
387 		/*
388 		 * If the fabric module supports an ISID based TransportID,
389 		 * save this value in binary from the fabric I_T Nexus now.
390 		 */
391 		if (se_tpg->se_tpg_tfo->sess_get_initiator_sid != NULL) {
392 			memset(&buf[0], 0, PR_REG_ISID_LEN);
393 			se_tpg->se_tpg_tfo->sess_get_initiator_sid(se_sess,
394 					&buf[0], PR_REG_ISID_LEN);
395 			se_sess->sess_bin_isid = get_unaligned_be64(&buf[0]);
396 		}
397 
398 		spin_lock_irqsave(&se_nacl->nacl_sess_lock, flags);
399 		/*
400 		 * The se_nacl->nacl_sess pointer will be set to the
401 		 * last active I_T Nexus for each struct se_node_acl.
402 		 */
403 		se_nacl->nacl_sess = se_sess;
404 
405 		list_add_tail(&se_sess->sess_acl_list,
406 			      &se_nacl->acl_sess_list);
407 		spin_unlock_irqrestore(&se_nacl->nacl_sess_lock, flags);
408 	}
409 	list_add_tail(&se_sess->sess_list, &se_tpg->tpg_sess_list);
410 
411 	pr_debug("TARGET_CORE[%s]: Registered fabric_sess_ptr: %p\n",
412 		se_tpg->se_tpg_tfo->fabric_name, se_sess->fabric_sess_ptr);
413 }
414 EXPORT_SYMBOL(__transport_register_session);
415 
416 void transport_register_session(
417 	struct se_portal_group *se_tpg,
418 	struct se_node_acl *se_nacl,
419 	struct se_session *se_sess,
420 	void *fabric_sess_ptr)
421 {
422 	unsigned long flags;
423 
424 	spin_lock_irqsave(&se_tpg->session_lock, flags);
425 	__transport_register_session(se_tpg, se_nacl, se_sess, fabric_sess_ptr);
426 	spin_unlock_irqrestore(&se_tpg->session_lock, flags);
427 }
428 EXPORT_SYMBOL(transport_register_session);
429 
430 struct se_session *
431 target_setup_session(struct se_portal_group *tpg,
432 		     unsigned int tag_num, unsigned int tag_size,
433 		     enum target_prot_op prot_op,
434 		     const char *initiatorname, void *private,
435 		     int (*callback)(struct se_portal_group *,
436 				     struct se_session *, void *))
437 {
438 	struct se_session *sess;
439 
440 	/*
441 	 * If the fabric driver is using percpu-ida based pre allocation
442 	 * of I/O descriptor tags, go ahead and perform that setup now..
443 	 */
444 	if (tag_num != 0)
445 		sess = transport_init_session_tags(tag_num, tag_size, prot_op);
446 	else
447 		sess = transport_alloc_session(prot_op);
448 
449 	if (IS_ERR(sess))
450 		return sess;
451 
452 	sess->se_node_acl = core_tpg_check_initiator_node_acl(tpg,
453 					(unsigned char *)initiatorname);
454 	if (!sess->se_node_acl) {
455 		transport_free_session(sess);
456 		return ERR_PTR(-EACCES);
457 	}
458 	/*
459 	 * Go ahead and perform any remaining fabric setup that is
460 	 * required before transport_register_session().
461 	 */
462 	if (callback != NULL) {
463 		int rc = callback(tpg, sess, private);
464 		if (rc) {
465 			transport_free_session(sess);
466 			return ERR_PTR(rc);
467 		}
468 	}
469 
470 	transport_register_session(tpg, sess->se_node_acl, sess, private);
471 	return sess;
472 }
473 EXPORT_SYMBOL(target_setup_session);
474 
475 ssize_t target_show_dynamic_sessions(struct se_portal_group *se_tpg, char *page)
476 {
477 	struct se_session *se_sess;
478 	ssize_t len = 0;
479 
480 	spin_lock_bh(&se_tpg->session_lock);
481 	list_for_each_entry(se_sess, &se_tpg->tpg_sess_list, sess_list) {
482 		if (!se_sess->se_node_acl)
483 			continue;
484 		if (!se_sess->se_node_acl->dynamic_node_acl)
485 			continue;
486 		if (strlen(se_sess->se_node_acl->initiatorname) + 1 + len > PAGE_SIZE)
487 			break;
488 
489 		len += snprintf(page + len, PAGE_SIZE - len, "%s\n",
490 				se_sess->se_node_acl->initiatorname);
491 		len += 1; /* Include NULL terminator */
492 	}
493 	spin_unlock_bh(&se_tpg->session_lock);
494 
495 	return len;
496 }
497 EXPORT_SYMBOL(target_show_dynamic_sessions);
498 
499 static void target_complete_nacl(struct kref *kref)
500 {
501 	struct se_node_acl *nacl = container_of(kref,
502 				struct se_node_acl, acl_kref);
503 	struct se_portal_group *se_tpg = nacl->se_tpg;
504 
505 	if (!nacl->dynamic_stop) {
506 		complete(&nacl->acl_free_comp);
507 		return;
508 	}
509 
510 	mutex_lock(&se_tpg->acl_node_mutex);
511 	list_del_init(&nacl->acl_list);
512 	mutex_unlock(&se_tpg->acl_node_mutex);
513 
514 	core_tpg_wait_for_nacl_pr_ref(nacl);
515 	core_free_device_list_for_node(nacl, se_tpg);
516 	kfree(nacl);
517 }
518 
519 void target_put_nacl(struct se_node_acl *nacl)
520 {
521 	kref_put(&nacl->acl_kref, target_complete_nacl);
522 }
523 EXPORT_SYMBOL(target_put_nacl);
524 
525 void transport_deregister_session_configfs(struct se_session *se_sess)
526 {
527 	struct se_node_acl *se_nacl;
528 	unsigned long flags;
529 	/*
530 	 * Used by struct se_node_acl's under ConfigFS to locate active struct se_session
531 	 */
532 	se_nacl = se_sess->se_node_acl;
533 	if (se_nacl) {
534 		spin_lock_irqsave(&se_nacl->nacl_sess_lock, flags);
535 		if (!list_empty(&se_sess->sess_acl_list))
536 			list_del_init(&se_sess->sess_acl_list);
537 		/*
538 		 * If the session list is empty, then clear the pointer.
539 		 * Otherwise, set the struct se_session pointer from the tail
540 		 * element of the per struct se_node_acl active session list.
541 		 */
542 		if (list_empty(&se_nacl->acl_sess_list))
543 			se_nacl->nacl_sess = NULL;
544 		else {
545 			se_nacl->nacl_sess = container_of(
546 					se_nacl->acl_sess_list.prev,
547 					struct se_session, sess_acl_list);
548 		}
549 		spin_unlock_irqrestore(&se_nacl->nacl_sess_lock, flags);
550 	}
551 }
552 EXPORT_SYMBOL(transport_deregister_session_configfs);
553 
554 void transport_free_session(struct se_session *se_sess)
555 {
556 	struct se_node_acl *se_nacl = se_sess->se_node_acl;
557 
558 	/*
559 	 * Drop the se_node_acl->nacl_kref obtained from within
560 	 * core_tpg_get_initiator_node_acl().
561 	 */
562 	if (se_nacl) {
563 		struct se_portal_group *se_tpg = se_nacl->se_tpg;
564 		const struct target_core_fabric_ops *se_tfo = se_tpg->se_tpg_tfo;
565 		unsigned long flags;
566 
567 		se_sess->se_node_acl = NULL;
568 
569 		/*
570 		 * Also determine if we need to drop the extra ->cmd_kref if
571 		 * it had been previously dynamically generated, and
572 		 * the endpoint is not caching dynamic ACLs.
573 		 */
574 		mutex_lock(&se_tpg->acl_node_mutex);
575 		if (se_nacl->dynamic_node_acl &&
576 		    !se_tfo->tpg_check_demo_mode_cache(se_tpg)) {
577 			spin_lock_irqsave(&se_nacl->nacl_sess_lock, flags);
578 			if (list_empty(&se_nacl->acl_sess_list))
579 				se_nacl->dynamic_stop = true;
580 			spin_unlock_irqrestore(&se_nacl->nacl_sess_lock, flags);
581 
582 			if (se_nacl->dynamic_stop)
583 				list_del_init(&se_nacl->acl_list);
584 		}
585 		mutex_unlock(&se_tpg->acl_node_mutex);
586 
587 		if (se_nacl->dynamic_stop)
588 			target_put_nacl(se_nacl);
589 
590 		target_put_nacl(se_nacl);
591 	}
592 	if (se_sess->sess_cmd_map) {
593 		sbitmap_queue_free(&se_sess->sess_tag_pool);
594 		kvfree(se_sess->sess_cmd_map);
595 	}
596 	transport_uninit_session(se_sess);
597 	kmem_cache_free(se_sess_cache, se_sess);
598 }
599 EXPORT_SYMBOL(transport_free_session);
600 
601 static int target_release_res(struct se_device *dev, void *data)
602 {
603 	struct se_session *sess = data;
604 
605 	if (dev->reservation_holder == sess)
606 		target_release_reservation(dev);
607 	return 0;
608 }
609 
610 void transport_deregister_session(struct se_session *se_sess)
611 {
612 	struct se_portal_group *se_tpg = se_sess->se_tpg;
613 	unsigned long flags;
614 
615 	if (!se_tpg) {
616 		transport_free_session(se_sess);
617 		return;
618 	}
619 
620 	spin_lock_irqsave(&se_tpg->session_lock, flags);
621 	list_del(&se_sess->sess_list);
622 	se_sess->se_tpg = NULL;
623 	se_sess->fabric_sess_ptr = NULL;
624 	spin_unlock_irqrestore(&se_tpg->session_lock, flags);
625 
626 	/*
627 	 * Since the session is being removed, release SPC-2
628 	 * reservations held by the session that is disappearing.
629 	 */
630 	target_for_each_device(target_release_res, se_sess);
631 
632 	pr_debug("TARGET_CORE[%s]: Deregistered fabric_sess\n",
633 		se_tpg->se_tpg_tfo->fabric_name);
634 	/*
635 	 * If last kref is dropping now for an explicit NodeACL, awake sleeping
636 	 * ->acl_free_comp caller to wakeup configfs se_node_acl->acl_group
637 	 * removal context from within transport_free_session() code.
638 	 *
639 	 * For dynamic ACL, target_put_nacl() uses target_complete_nacl()
640 	 * to release all remaining generate_node_acl=1 created ACL resources.
641 	 */
642 
643 	transport_free_session(se_sess);
644 }
645 EXPORT_SYMBOL(transport_deregister_session);
646 
647 void target_remove_session(struct se_session *se_sess)
648 {
649 	transport_deregister_session_configfs(se_sess);
650 	transport_deregister_session(se_sess);
651 }
652 EXPORT_SYMBOL(target_remove_session);
653 
654 static void target_remove_from_state_list(struct se_cmd *cmd)
655 {
656 	struct se_device *dev = cmd->se_dev;
657 	unsigned long flags;
658 
659 	if (!dev)
660 		return;
661 
662 	spin_lock_irqsave(&dev->queues[cmd->cpuid].lock, flags);
663 	if (cmd->state_active) {
664 		list_del(&cmd->state_list);
665 		cmd->state_active = false;
666 	}
667 	spin_unlock_irqrestore(&dev->queues[cmd->cpuid].lock, flags);
668 }
669 
670 /*
671  * This function is called by the target core after the target core has
672  * finished processing a SCSI command or SCSI TMF. Both the regular command
673  * processing code and the code for aborting commands can call this
674  * function. CMD_T_STOP is set if and only if another thread is waiting
675  * inside transport_wait_for_tasks() for t_transport_stop_comp.
676  */
677 static int transport_cmd_check_stop_to_fabric(struct se_cmd *cmd)
678 {
679 	unsigned long flags;
680 
681 	target_remove_from_state_list(cmd);
682 
683 	/*
684 	 * Clear struct se_cmd->se_lun before the handoff to FE.
685 	 */
686 	cmd->se_lun = NULL;
687 
688 	spin_lock_irqsave(&cmd->t_state_lock, flags);
689 	/*
690 	 * Determine if frontend context caller is requesting the stopping of
691 	 * this command for frontend exceptions.
692 	 */
693 	if (cmd->transport_state & CMD_T_STOP) {
694 		pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08llx\n",
695 			__func__, __LINE__, cmd->tag);
696 
697 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
698 
699 		complete_all(&cmd->t_transport_stop_comp);
700 		return 1;
701 	}
702 	cmd->transport_state &= ~CMD_T_ACTIVE;
703 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
704 
705 	/*
706 	 * Some fabric modules like tcm_loop can release their internally
707 	 * allocated I/O reference and struct se_cmd now.
708 	 *
709 	 * Fabric modules are expected to return '1' here if the se_cmd being
710 	 * passed is released at this point, or zero if not being released.
711 	 */
712 	return cmd->se_tfo->check_stop_free(cmd);
713 }
714 
715 static void transport_lun_remove_cmd(struct se_cmd *cmd)
716 {
717 	struct se_lun *lun = cmd->se_lun;
718 
719 	if (!lun)
720 		return;
721 
722 	if (cmpxchg(&cmd->lun_ref_active, true, false))
723 		percpu_ref_put(&lun->lun_ref);
724 }
725 
726 static void target_complete_failure_work(struct work_struct *work)
727 {
728 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
729 
730 	transport_generic_request_failure(cmd,
731 			TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE);
732 }
733 
734 /*
735  * Used when asking transport to copy Sense Data from the underlying
736  * Linux/SCSI struct scsi_cmnd
737  */
738 static unsigned char *transport_get_sense_buffer(struct se_cmd *cmd)
739 {
740 	struct se_device *dev = cmd->se_dev;
741 
742 	WARN_ON(!cmd->se_lun);
743 
744 	if (!dev)
745 		return NULL;
746 
747 	if (cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION)
748 		return NULL;
749 
750 	cmd->scsi_sense_length = TRANSPORT_SENSE_BUFFER;
751 
752 	pr_debug("HBA_[%u]_PLUG[%s]: Requesting sense for SAM STATUS: 0x%02x\n",
753 		dev->se_hba->hba_id, dev->transport->name, cmd->scsi_status);
754 	return cmd->sense_buffer;
755 }
756 
757 void transport_copy_sense_to_cmd(struct se_cmd *cmd, unsigned char *sense)
758 {
759 	unsigned char *cmd_sense_buf;
760 	unsigned long flags;
761 
762 	spin_lock_irqsave(&cmd->t_state_lock, flags);
763 	cmd_sense_buf = transport_get_sense_buffer(cmd);
764 	if (!cmd_sense_buf) {
765 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
766 		return;
767 	}
768 
769 	cmd->se_cmd_flags |= SCF_TRANSPORT_TASK_SENSE;
770 	memcpy(cmd_sense_buf, sense, cmd->scsi_sense_length);
771 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
772 }
773 EXPORT_SYMBOL(transport_copy_sense_to_cmd);
774 
775 static void target_handle_abort(struct se_cmd *cmd)
776 {
777 	bool tas = cmd->transport_state & CMD_T_TAS;
778 	bool ack_kref = cmd->se_cmd_flags & SCF_ACK_KREF;
779 	int ret;
780 
781 	pr_debug("tag %#llx: send_abort_response = %d\n", cmd->tag, tas);
782 
783 	if (tas) {
784 		if (!(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)) {
785 			cmd->scsi_status = SAM_STAT_TASK_ABORTED;
786 			pr_debug("Setting SAM_STAT_TASK_ABORTED status for CDB: 0x%02x, ITT: 0x%08llx\n",
787 				 cmd->t_task_cdb[0], cmd->tag);
788 			trace_target_cmd_complete(cmd);
789 			ret = cmd->se_tfo->queue_status(cmd);
790 			if (ret) {
791 				transport_handle_queue_full(cmd, cmd->se_dev,
792 							    ret, false);
793 				return;
794 			}
795 		} else {
796 			cmd->se_tmr_req->response = TMR_FUNCTION_REJECTED;
797 			cmd->se_tfo->queue_tm_rsp(cmd);
798 		}
799 	} else {
800 		/*
801 		 * Allow the fabric driver to unmap any resources before
802 		 * releasing the descriptor via TFO->release_cmd().
803 		 */
804 		cmd->se_tfo->aborted_task(cmd);
805 		if (ack_kref)
806 			WARN_ON_ONCE(target_put_sess_cmd(cmd) != 0);
807 		/*
808 		 * To do: establish a unit attention condition on the I_T
809 		 * nexus associated with cmd. See also the paragraph "Aborting
810 		 * commands" in SAM.
811 		 */
812 	}
813 
814 	WARN_ON_ONCE(kref_read(&cmd->cmd_kref) == 0);
815 
816 	transport_lun_remove_cmd(cmd);
817 
818 	transport_cmd_check_stop_to_fabric(cmd);
819 }
820 
821 static void target_abort_work(struct work_struct *work)
822 {
823 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
824 
825 	target_handle_abort(cmd);
826 }
827 
828 static bool target_cmd_interrupted(struct se_cmd *cmd)
829 {
830 	int post_ret;
831 
832 	if (cmd->transport_state & CMD_T_ABORTED) {
833 		if (cmd->transport_complete_callback)
834 			cmd->transport_complete_callback(cmd, false, &post_ret);
835 		INIT_WORK(&cmd->work, target_abort_work);
836 		queue_work(target_completion_wq, &cmd->work);
837 		return true;
838 	} else if (cmd->transport_state & CMD_T_STOP) {
839 		if (cmd->transport_complete_callback)
840 			cmd->transport_complete_callback(cmd, false, &post_ret);
841 		complete_all(&cmd->t_transport_stop_comp);
842 		return true;
843 	}
844 
845 	return false;
846 }
847 
848 /* May be called from interrupt context so must not sleep. */
849 void target_complete_cmd(struct se_cmd *cmd, u8 scsi_status)
850 {
851 	int success;
852 	unsigned long flags;
853 
854 	if (target_cmd_interrupted(cmd))
855 		return;
856 
857 	cmd->scsi_status = scsi_status;
858 
859 	spin_lock_irqsave(&cmd->t_state_lock, flags);
860 	switch (cmd->scsi_status) {
861 	case SAM_STAT_CHECK_CONDITION:
862 		if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE)
863 			success = 1;
864 		else
865 			success = 0;
866 		break;
867 	default:
868 		success = 1;
869 		break;
870 	}
871 
872 	cmd->t_state = TRANSPORT_COMPLETE;
873 	cmd->transport_state |= (CMD_T_COMPLETE | CMD_T_ACTIVE);
874 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
875 
876 	INIT_WORK(&cmd->work, success ? target_complete_ok_work :
877 		  target_complete_failure_work);
878 	queue_work_on(cmd->cpuid, target_completion_wq, &cmd->work);
879 }
880 EXPORT_SYMBOL(target_complete_cmd);
881 
882 void target_complete_cmd_with_length(struct se_cmd *cmd, u8 scsi_status, int length)
883 {
884 	if ((scsi_status == SAM_STAT_GOOD ||
885 	     cmd->se_cmd_flags & SCF_TREAT_READ_AS_NORMAL) &&
886 	    length < cmd->data_length) {
887 		if (cmd->se_cmd_flags & SCF_UNDERFLOW_BIT) {
888 			cmd->residual_count += cmd->data_length - length;
889 		} else {
890 			cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
891 			cmd->residual_count = cmd->data_length - length;
892 		}
893 
894 		cmd->data_length = length;
895 	}
896 
897 	target_complete_cmd(cmd, scsi_status);
898 }
899 EXPORT_SYMBOL(target_complete_cmd_with_length);
900 
901 static void target_add_to_state_list(struct se_cmd *cmd)
902 {
903 	struct se_device *dev = cmd->se_dev;
904 	unsigned long flags;
905 
906 	spin_lock_irqsave(&dev->queues[cmd->cpuid].lock, flags);
907 	if (!cmd->state_active) {
908 		list_add_tail(&cmd->state_list,
909 			      &dev->queues[cmd->cpuid].state_list);
910 		cmd->state_active = true;
911 	}
912 	spin_unlock_irqrestore(&dev->queues[cmd->cpuid].lock, flags);
913 }
914 
915 /*
916  * Handle QUEUE_FULL / -EAGAIN and -ENOMEM status
917  */
918 static void transport_write_pending_qf(struct se_cmd *cmd);
919 static void transport_complete_qf(struct se_cmd *cmd);
920 
921 void target_qf_do_work(struct work_struct *work)
922 {
923 	struct se_device *dev = container_of(work, struct se_device,
924 					qf_work_queue);
925 	LIST_HEAD(qf_cmd_list);
926 	struct se_cmd *cmd, *cmd_tmp;
927 
928 	spin_lock_irq(&dev->qf_cmd_lock);
929 	list_splice_init(&dev->qf_cmd_list, &qf_cmd_list);
930 	spin_unlock_irq(&dev->qf_cmd_lock);
931 
932 	list_for_each_entry_safe(cmd, cmd_tmp, &qf_cmd_list, se_qf_node) {
933 		list_del(&cmd->se_qf_node);
934 		atomic_dec_mb(&dev->dev_qf_count);
935 
936 		pr_debug("Processing %s cmd: %p QUEUE_FULL in work queue"
937 			" context: %s\n", cmd->se_tfo->fabric_name, cmd,
938 			(cmd->t_state == TRANSPORT_COMPLETE_QF_OK) ? "COMPLETE_OK" :
939 			(cmd->t_state == TRANSPORT_COMPLETE_QF_WP) ? "WRITE_PENDING"
940 			: "UNKNOWN");
941 
942 		if (cmd->t_state == TRANSPORT_COMPLETE_QF_WP)
943 			transport_write_pending_qf(cmd);
944 		else if (cmd->t_state == TRANSPORT_COMPLETE_QF_OK ||
945 			 cmd->t_state == TRANSPORT_COMPLETE_QF_ERR)
946 			transport_complete_qf(cmd);
947 	}
948 }
949 
950 unsigned char *transport_dump_cmd_direction(struct se_cmd *cmd)
951 {
952 	switch (cmd->data_direction) {
953 	case DMA_NONE:
954 		return "NONE";
955 	case DMA_FROM_DEVICE:
956 		return "READ";
957 	case DMA_TO_DEVICE:
958 		return "WRITE";
959 	case DMA_BIDIRECTIONAL:
960 		return "BIDI";
961 	default:
962 		break;
963 	}
964 
965 	return "UNKNOWN";
966 }
967 
968 void transport_dump_dev_state(
969 	struct se_device *dev,
970 	char *b,
971 	int *bl)
972 {
973 	*bl += sprintf(b + *bl, "Status: ");
974 	if (dev->export_count)
975 		*bl += sprintf(b + *bl, "ACTIVATED");
976 	else
977 		*bl += sprintf(b + *bl, "DEACTIVATED");
978 
979 	*bl += sprintf(b + *bl, "  Max Queue Depth: %d", dev->queue_depth);
980 	*bl += sprintf(b + *bl, "  SectorSize: %u  HwMaxSectors: %u\n",
981 		dev->dev_attrib.block_size,
982 		dev->dev_attrib.hw_max_sectors);
983 	*bl += sprintf(b + *bl, "        ");
984 }
985 
986 void transport_dump_vpd_proto_id(
987 	struct t10_vpd *vpd,
988 	unsigned char *p_buf,
989 	int p_buf_len)
990 {
991 	unsigned char buf[VPD_TMP_BUF_SIZE];
992 	int len;
993 
994 	memset(buf, 0, VPD_TMP_BUF_SIZE);
995 	len = sprintf(buf, "T10 VPD Protocol Identifier: ");
996 
997 	switch (vpd->protocol_identifier) {
998 	case 0x00:
999 		sprintf(buf+len, "Fibre Channel\n");
1000 		break;
1001 	case 0x10:
1002 		sprintf(buf+len, "Parallel SCSI\n");
1003 		break;
1004 	case 0x20:
1005 		sprintf(buf+len, "SSA\n");
1006 		break;
1007 	case 0x30:
1008 		sprintf(buf+len, "IEEE 1394\n");
1009 		break;
1010 	case 0x40:
1011 		sprintf(buf+len, "SCSI Remote Direct Memory Access"
1012 				" Protocol\n");
1013 		break;
1014 	case 0x50:
1015 		sprintf(buf+len, "Internet SCSI (iSCSI)\n");
1016 		break;
1017 	case 0x60:
1018 		sprintf(buf+len, "SAS Serial SCSI Protocol\n");
1019 		break;
1020 	case 0x70:
1021 		sprintf(buf+len, "Automation/Drive Interface Transport"
1022 				" Protocol\n");
1023 		break;
1024 	case 0x80:
1025 		sprintf(buf+len, "AT Attachment Interface ATA/ATAPI\n");
1026 		break;
1027 	default:
1028 		sprintf(buf+len, "Unknown 0x%02x\n",
1029 				vpd->protocol_identifier);
1030 		break;
1031 	}
1032 
1033 	if (p_buf)
1034 		strncpy(p_buf, buf, p_buf_len);
1035 	else
1036 		pr_debug("%s", buf);
1037 }
1038 
1039 void
1040 transport_set_vpd_proto_id(struct t10_vpd *vpd, unsigned char *page_83)
1041 {
1042 	/*
1043 	 * Check if the Protocol Identifier Valid (PIV) bit is set..
1044 	 *
1045 	 * from spc3r23.pdf section 7.5.1
1046 	 */
1047 	 if (page_83[1] & 0x80) {
1048 		vpd->protocol_identifier = (page_83[0] & 0xf0);
1049 		vpd->protocol_identifier_set = 1;
1050 		transport_dump_vpd_proto_id(vpd, NULL, 0);
1051 	}
1052 }
1053 EXPORT_SYMBOL(transport_set_vpd_proto_id);
1054 
1055 int transport_dump_vpd_assoc(
1056 	struct t10_vpd *vpd,
1057 	unsigned char *p_buf,
1058 	int p_buf_len)
1059 {
1060 	unsigned char buf[VPD_TMP_BUF_SIZE];
1061 	int ret = 0;
1062 	int len;
1063 
1064 	memset(buf, 0, VPD_TMP_BUF_SIZE);
1065 	len = sprintf(buf, "T10 VPD Identifier Association: ");
1066 
1067 	switch (vpd->association) {
1068 	case 0x00:
1069 		sprintf(buf+len, "addressed logical unit\n");
1070 		break;
1071 	case 0x10:
1072 		sprintf(buf+len, "target port\n");
1073 		break;
1074 	case 0x20:
1075 		sprintf(buf+len, "SCSI target device\n");
1076 		break;
1077 	default:
1078 		sprintf(buf+len, "Unknown 0x%02x\n", vpd->association);
1079 		ret = -EINVAL;
1080 		break;
1081 	}
1082 
1083 	if (p_buf)
1084 		strncpy(p_buf, buf, p_buf_len);
1085 	else
1086 		pr_debug("%s", buf);
1087 
1088 	return ret;
1089 }
1090 
1091 int transport_set_vpd_assoc(struct t10_vpd *vpd, unsigned char *page_83)
1092 {
1093 	/*
1094 	 * The VPD identification association..
1095 	 *
1096 	 * from spc3r23.pdf Section 7.6.3.1 Table 297
1097 	 */
1098 	vpd->association = (page_83[1] & 0x30);
1099 	return transport_dump_vpd_assoc(vpd, NULL, 0);
1100 }
1101 EXPORT_SYMBOL(transport_set_vpd_assoc);
1102 
1103 int transport_dump_vpd_ident_type(
1104 	struct t10_vpd *vpd,
1105 	unsigned char *p_buf,
1106 	int p_buf_len)
1107 {
1108 	unsigned char buf[VPD_TMP_BUF_SIZE];
1109 	int ret = 0;
1110 	int len;
1111 
1112 	memset(buf, 0, VPD_TMP_BUF_SIZE);
1113 	len = sprintf(buf, "T10 VPD Identifier Type: ");
1114 
1115 	switch (vpd->device_identifier_type) {
1116 	case 0x00:
1117 		sprintf(buf+len, "Vendor specific\n");
1118 		break;
1119 	case 0x01:
1120 		sprintf(buf+len, "T10 Vendor ID based\n");
1121 		break;
1122 	case 0x02:
1123 		sprintf(buf+len, "EUI-64 based\n");
1124 		break;
1125 	case 0x03:
1126 		sprintf(buf+len, "NAA\n");
1127 		break;
1128 	case 0x04:
1129 		sprintf(buf+len, "Relative target port identifier\n");
1130 		break;
1131 	case 0x08:
1132 		sprintf(buf+len, "SCSI name string\n");
1133 		break;
1134 	default:
1135 		sprintf(buf+len, "Unsupported: 0x%02x\n",
1136 				vpd->device_identifier_type);
1137 		ret = -EINVAL;
1138 		break;
1139 	}
1140 
1141 	if (p_buf) {
1142 		if (p_buf_len < strlen(buf)+1)
1143 			return -EINVAL;
1144 		strncpy(p_buf, buf, p_buf_len);
1145 	} else {
1146 		pr_debug("%s", buf);
1147 	}
1148 
1149 	return ret;
1150 }
1151 
1152 int transport_set_vpd_ident_type(struct t10_vpd *vpd, unsigned char *page_83)
1153 {
1154 	/*
1155 	 * The VPD identifier type..
1156 	 *
1157 	 * from spc3r23.pdf Section 7.6.3.1 Table 298
1158 	 */
1159 	vpd->device_identifier_type = (page_83[1] & 0x0f);
1160 	return transport_dump_vpd_ident_type(vpd, NULL, 0);
1161 }
1162 EXPORT_SYMBOL(transport_set_vpd_ident_type);
1163 
1164 int transport_dump_vpd_ident(
1165 	struct t10_vpd *vpd,
1166 	unsigned char *p_buf,
1167 	int p_buf_len)
1168 {
1169 	unsigned char buf[VPD_TMP_BUF_SIZE];
1170 	int ret = 0;
1171 
1172 	memset(buf, 0, VPD_TMP_BUF_SIZE);
1173 
1174 	switch (vpd->device_identifier_code_set) {
1175 	case 0x01: /* Binary */
1176 		snprintf(buf, sizeof(buf),
1177 			"T10 VPD Binary Device Identifier: %s\n",
1178 			&vpd->device_identifier[0]);
1179 		break;
1180 	case 0x02: /* ASCII */
1181 		snprintf(buf, sizeof(buf),
1182 			"T10 VPD ASCII Device Identifier: %s\n",
1183 			&vpd->device_identifier[0]);
1184 		break;
1185 	case 0x03: /* UTF-8 */
1186 		snprintf(buf, sizeof(buf),
1187 			"T10 VPD UTF-8 Device Identifier: %s\n",
1188 			&vpd->device_identifier[0]);
1189 		break;
1190 	default:
1191 		sprintf(buf, "T10 VPD Device Identifier encoding unsupported:"
1192 			" 0x%02x", vpd->device_identifier_code_set);
1193 		ret = -EINVAL;
1194 		break;
1195 	}
1196 
1197 	if (p_buf)
1198 		strncpy(p_buf, buf, p_buf_len);
1199 	else
1200 		pr_debug("%s", buf);
1201 
1202 	return ret;
1203 }
1204 
1205 int
1206 transport_set_vpd_ident(struct t10_vpd *vpd, unsigned char *page_83)
1207 {
1208 	static const char hex_str[] = "0123456789abcdef";
1209 	int j = 0, i = 4; /* offset to start of the identifier */
1210 
1211 	/*
1212 	 * The VPD Code Set (encoding)
1213 	 *
1214 	 * from spc3r23.pdf Section 7.6.3.1 Table 296
1215 	 */
1216 	vpd->device_identifier_code_set = (page_83[0] & 0x0f);
1217 	switch (vpd->device_identifier_code_set) {
1218 	case 0x01: /* Binary */
1219 		vpd->device_identifier[j++] =
1220 				hex_str[vpd->device_identifier_type];
1221 		while (i < (4 + page_83[3])) {
1222 			vpd->device_identifier[j++] =
1223 				hex_str[(page_83[i] & 0xf0) >> 4];
1224 			vpd->device_identifier[j++] =
1225 				hex_str[page_83[i] & 0x0f];
1226 			i++;
1227 		}
1228 		break;
1229 	case 0x02: /* ASCII */
1230 	case 0x03: /* UTF-8 */
1231 		while (i < (4 + page_83[3]))
1232 			vpd->device_identifier[j++] = page_83[i++];
1233 		break;
1234 	default:
1235 		break;
1236 	}
1237 
1238 	return transport_dump_vpd_ident(vpd, NULL, 0);
1239 }
1240 EXPORT_SYMBOL(transport_set_vpd_ident);
1241 
1242 static sense_reason_t
1243 target_check_max_data_sg_nents(struct se_cmd *cmd, struct se_device *dev,
1244 			       unsigned int size)
1245 {
1246 	u32 mtl;
1247 
1248 	if (!cmd->se_tfo->max_data_sg_nents)
1249 		return TCM_NO_SENSE;
1250 	/*
1251 	 * Check if fabric enforced maximum SGL entries per I/O descriptor
1252 	 * exceeds se_cmd->data_length.  If true, set SCF_UNDERFLOW_BIT +
1253 	 * residual_count and reduce original cmd->data_length to maximum
1254 	 * length based on single PAGE_SIZE entry scatter-lists.
1255 	 */
1256 	mtl = (cmd->se_tfo->max_data_sg_nents * PAGE_SIZE);
1257 	if (cmd->data_length > mtl) {
1258 		/*
1259 		 * If an existing CDB overflow is present, calculate new residual
1260 		 * based on CDB size minus fabric maximum transfer length.
1261 		 *
1262 		 * If an existing CDB underflow is present, calculate new residual
1263 		 * based on original cmd->data_length minus fabric maximum transfer
1264 		 * length.
1265 		 *
1266 		 * Otherwise, set the underflow residual based on cmd->data_length
1267 		 * minus fabric maximum transfer length.
1268 		 */
1269 		if (cmd->se_cmd_flags & SCF_OVERFLOW_BIT) {
1270 			cmd->residual_count = (size - mtl);
1271 		} else if (cmd->se_cmd_flags & SCF_UNDERFLOW_BIT) {
1272 			u32 orig_dl = size + cmd->residual_count;
1273 			cmd->residual_count = (orig_dl - mtl);
1274 		} else {
1275 			cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
1276 			cmd->residual_count = (cmd->data_length - mtl);
1277 		}
1278 		cmd->data_length = mtl;
1279 		/*
1280 		 * Reset sbc_check_prot() calculated protection payload
1281 		 * length based upon the new smaller MTL.
1282 		 */
1283 		if (cmd->prot_length) {
1284 			u32 sectors = (mtl / dev->dev_attrib.block_size);
1285 			cmd->prot_length = dev->prot_length * sectors;
1286 		}
1287 	}
1288 	return TCM_NO_SENSE;
1289 }
1290 
1291 /**
1292  * target_cmd_size_check - Check whether there will be a residual.
1293  * @cmd: SCSI command.
1294  * @size: Data buffer size derived from CDB. The data buffer size provided by
1295  *   the SCSI transport driver is available in @cmd->data_length.
1296  *
1297  * Compare the data buffer size from the CDB with the data buffer limit from the transport
1298  * header. Set @cmd->residual_count and SCF_OVERFLOW_BIT or SCF_UNDERFLOW_BIT if necessary.
1299  *
1300  * Note: target drivers set @cmd->data_length by calling transport_init_se_cmd().
1301  *
1302  * Return: TCM_NO_SENSE
1303  */
1304 sense_reason_t
1305 target_cmd_size_check(struct se_cmd *cmd, unsigned int size)
1306 {
1307 	struct se_device *dev = cmd->se_dev;
1308 
1309 	if (cmd->unknown_data_length) {
1310 		cmd->data_length = size;
1311 	} else if (size != cmd->data_length) {
1312 		pr_warn_ratelimited("TARGET_CORE[%s]: Expected Transfer Length:"
1313 			" %u does not match SCSI CDB Length: %u for SAM Opcode:"
1314 			" 0x%02x\n", cmd->se_tfo->fabric_name,
1315 				cmd->data_length, size, cmd->t_task_cdb[0]);
1316 
1317 		if (cmd->data_direction == DMA_TO_DEVICE) {
1318 			if (cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) {
1319 				pr_err_ratelimited("Rejecting underflow/overflow"
1320 						   " for WRITE data CDB\n");
1321 				return TCM_INVALID_CDB_FIELD;
1322 			}
1323 			/*
1324 			 * Some fabric drivers like iscsi-target still expect to
1325 			 * always reject overflow writes.  Reject this case until
1326 			 * full fabric driver level support for overflow writes
1327 			 * is introduced tree-wide.
1328 			 */
1329 			if (size > cmd->data_length) {
1330 				pr_err_ratelimited("Rejecting overflow for"
1331 						   " WRITE control CDB\n");
1332 				return TCM_INVALID_CDB_FIELD;
1333 			}
1334 		}
1335 		/*
1336 		 * Reject READ_* or WRITE_* with overflow/underflow for
1337 		 * type SCF_SCSI_DATA_CDB.
1338 		 */
1339 		if (dev->dev_attrib.block_size != 512)  {
1340 			pr_err("Failing OVERFLOW/UNDERFLOW for LBA op"
1341 				" CDB on non 512-byte sector setup subsystem"
1342 				" plugin: %s\n", dev->transport->name);
1343 			/* Returns CHECK_CONDITION + INVALID_CDB_FIELD */
1344 			return TCM_INVALID_CDB_FIELD;
1345 		}
1346 		/*
1347 		 * For the overflow case keep the existing fabric provided
1348 		 * ->data_length.  Otherwise for the underflow case, reset
1349 		 * ->data_length to the smaller SCSI expected data transfer
1350 		 * length.
1351 		 */
1352 		if (size > cmd->data_length) {
1353 			cmd->se_cmd_flags |= SCF_OVERFLOW_BIT;
1354 			cmd->residual_count = (size - cmd->data_length);
1355 		} else {
1356 			cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
1357 			cmd->residual_count = (cmd->data_length - size);
1358 			cmd->data_length = size;
1359 		}
1360 	}
1361 
1362 	return target_check_max_data_sg_nents(cmd, dev, size);
1363 
1364 }
1365 
1366 /*
1367  * Used by fabric modules containing a local struct se_cmd within their
1368  * fabric dependent per I/O descriptor.
1369  *
1370  * Preserves the value of @cmd->tag.
1371  */
1372 void transport_init_se_cmd(
1373 	struct se_cmd *cmd,
1374 	const struct target_core_fabric_ops *tfo,
1375 	struct se_session *se_sess,
1376 	u32 data_length,
1377 	int data_direction,
1378 	int task_attr,
1379 	unsigned char *sense_buffer, u64 unpacked_lun)
1380 {
1381 	INIT_LIST_HEAD(&cmd->se_delayed_node);
1382 	INIT_LIST_HEAD(&cmd->se_qf_node);
1383 	INIT_LIST_HEAD(&cmd->se_cmd_list);
1384 	INIT_LIST_HEAD(&cmd->state_list);
1385 	init_completion(&cmd->t_transport_stop_comp);
1386 	cmd->free_compl = NULL;
1387 	cmd->abrt_compl = NULL;
1388 	spin_lock_init(&cmd->t_state_lock);
1389 	INIT_WORK(&cmd->work, NULL);
1390 	kref_init(&cmd->cmd_kref);
1391 
1392 	cmd->se_tfo = tfo;
1393 	cmd->se_sess = se_sess;
1394 	cmd->data_length = data_length;
1395 	cmd->data_direction = data_direction;
1396 	cmd->sam_task_attr = task_attr;
1397 	cmd->sense_buffer = sense_buffer;
1398 	cmd->orig_fe_lun = unpacked_lun;
1399 
1400 	if (!(cmd->se_cmd_flags & SCF_USE_CPUID))
1401 		cmd->cpuid = smp_processor_id();
1402 
1403 	cmd->state_active = false;
1404 }
1405 EXPORT_SYMBOL(transport_init_se_cmd);
1406 
1407 static sense_reason_t
1408 transport_check_alloc_task_attr(struct se_cmd *cmd)
1409 {
1410 	struct se_device *dev = cmd->se_dev;
1411 
1412 	/*
1413 	 * Check if SAM Task Attribute emulation is enabled for this
1414 	 * struct se_device storage object
1415 	 */
1416 	if (dev->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
1417 		return 0;
1418 
1419 	if (cmd->sam_task_attr == TCM_ACA_TAG) {
1420 		pr_debug("SAM Task Attribute ACA"
1421 			" emulation is not supported\n");
1422 		return TCM_INVALID_CDB_FIELD;
1423 	}
1424 
1425 	return 0;
1426 }
1427 
1428 sense_reason_t
1429 target_cmd_init_cdb(struct se_cmd *cmd, unsigned char *cdb)
1430 {
1431 	sense_reason_t ret;
1432 
1433 	cmd->t_task_cdb = &cmd->__t_task_cdb[0];
1434 	/*
1435 	 * Ensure that the received CDB is less than the max (252 + 8) bytes
1436 	 * for VARIABLE_LENGTH_CMD
1437 	 */
1438 	if (scsi_command_size(cdb) > SCSI_MAX_VARLEN_CDB_SIZE) {
1439 		pr_err("Received SCSI CDB with command_size: %d that"
1440 			" exceeds SCSI_MAX_VARLEN_CDB_SIZE: %d\n",
1441 			scsi_command_size(cdb), SCSI_MAX_VARLEN_CDB_SIZE);
1442 		ret = TCM_INVALID_CDB_FIELD;
1443 		goto err;
1444 	}
1445 	/*
1446 	 * If the received CDB is larger than TCM_MAX_COMMAND_SIZE,
1447 	 * allocate the additional extended CDB buffer now..  Otherwise
1448 	 * setup the pointer from __t_task_cdb to t_task_cdb.
1449 	 */
1450 	if (scsi_command_size(cdb) > sizeof(cmd->__t_task_cdb)) {
1451 		cmd->t_task_cdb = kzalloc(scsi_command_size(cdb),
1452 						GFP_KERNEL);
1453 		if (!cmd->t_task_cdb) {
1454 			pr_err("Unable to allocate cmd->t_task_cdb"
1455 				" %u > sizeof(cmd->__t_task_cdb): %lu ops\n",
1456 				scsi_command_size(cdb),
1457 				(unsigned long)sizeof(cmd->__t_task_cdb));
1458 			ret = TCM_OUT_OF_RESOURCES;
1459 			goto err;
1460 		}
1461 	}
1462 	/*
1463 	 * Copy the original CDB into cmd->
1464 	 */
1465 	memcpy(cmd->t_task_cdb, cdb, scsi_command_size(cdb));
1466 
1467 	trace_target_sequencer_start(cmd);
1468 	return 0;
1469 
1470 err:
1471 	/*
1472 	 * Copy the CDB here to allow trace_target_cmd_complete() to
1473 	 * print the cdb to the trace buffers.
1474 	 */
1475 	memcpy(cmd->t_task_cdb, cdb, min(scsi_command_size(cdb),
1476 					 (unsigned int)TCM_MAX_COMMAND_SIZE));
1477 	return ret;
1478 }
1479 EXPORT_SYMBOL(target_cmd_init_cdb);
1480 
1481 sense_reason_t
1482 target_cmd_parse_cdb(struct se_cmd *cmd)
1483 {
1484 	struct se_device *dev = cmd->se_dev;
1485 	sense_reason_t ret;
1486 
1487 	ret = dev->transport->parse_cdb(cmd);
1488 	if (ret == TCM_UNSUPPORTED_SCSI_OPCODE)
1489 		pr_warn_ratelimited("%s/%s: Unsupported SCSI Opcode 0x%02x, sending CHECK_CONDITION.\n",
1490 				    cmd->se_tfo->fabric_name,
1491 				    cmd->se_sess->se_node_acl->initiatorname,
1492 				    cmd->t_task_cdb[0]);
1493 	if (ret)
1494 		return ret;
1495 
1496 	ret = transport_check_alloc_task_attr(cmd);
1497 	if (ret)
1498 		return ret;
1499 
1500 	cmd->se_cmd_flags |= SCF_SUPPORTED_SAM_OPCODE;
1501 	atomic_long_inc(&cmd->se_lun->lun_stats.cmd_pdus);
1502 	return 0;
1503 }
1504 EXPORT_SYMBOL(target_cmd_parse_cdb);
1505 
1506 /*
1507  * Used by fabric module frontends to queue tasks directly.
1508  * May only be used from process context.
1509  */
1510 int transport_handle_cdb_direct(
1511 	struct se_cmd *cmd)
1512 {
1513 	sense_reason_t ret;
1514 
1515 	if (!cmd->se_lun) {
1516 		dump_stack();
1517 		pr_err("cmd->se_lun is NULL\n");
1518 		return -EINVAL;
1519 	}
1520 	if (in_interrupt()) {
1521 		dump_stack();
1522 		pr_err("transport_generic_handle_cdb cannot be called"
1523 				" from interrupt context\n");
1524 		return -EINVAL;
1525 	}
1526 	/*
1527 	 * Set TRANSPORT_NEW_CMD state and CMD_T_ACTIVE to ensure that
1528 	 * outstanding descriptors are handled correctly during shutdown via
1529 	 * transport_wait_for_tasks()
1530 	 *
1531 	 * Also, we don't take cmd->t_state_lock here as we only expect
1532 	 * this to be called for initial descriptor submission.
1533 	 */
1534 	cmd->t_state = TRANSPORT_NEW_CMD;
1535 	cmd->transport_state |= CMD_T_ACTIVE;
1536 
1537 	/*
1538 	 * transport_generic_new_cmd() is already handling QUEUE_FULL,
1539 	 * so follow TRANSPORT_NEW_CMD processing thread context usage
1540 	 * and call transport_generic_request_failure() if necessary..
1541 	 */
1542 	ret = transport_generic_new_cmd(cmd);
1543 	if (ret)
1544 		transport_generic_request_failure(cmd, ret);
1545 	return 0;
1546 }
1547 EXPORT_SYMBOL(transport_handle_cdb_direct);
1548 
1549 sense_reason_t
1550 transport_generic_map_mem_to_cmd(struct se_cmd *cmd, struct scatterlist *sgl,
1551 		u32 sgl_count, struct scatterlist *sgl_bidi, u32 sgl_bidi_count)
1552 {
1553 	if (!sgl || !sgl_count)
1554 		return 0;
1555 
1556 	/*
1557 	 * Reject SCSI data overflow with map_mem_to_cmd() as incoming
1558 	 * scatterlists already have been set to follow what the fabric
1559 	 * passes for the original expected data transfer length.
1560 	 */
1561 	if (cmd->se_cmd_flags & SCF_OVERFLOW_BIT) {
1562 		pr_warn("Rejecting SCSI DATA overflow for fabric using"
1563 			" SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC\n");
1564 		return TCM_INVALID_CDB_FIELD;
1565 	}
1566 
1567 	cmd->t_data_sg = sgl;
1568 	cmd->t_data_nents = sgl_count;
1569 	cmd->t_bidi_data_sg = sgl_bidi;
1570 	cmd->t_bidi_data_nents = sgl_bidi_count;
1571 
1572 	cmd->se_cmd_flags |= SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC;
1573 	return 0;
1574 }
1575 
1576 /**
1577  * target_submit_cmd_map_sgls - lookup unpacked lun and submit uninitialized
1578  * 			 se_cmd + use pre-allocated SGL memory.
1579  *
1580  * @se_cmd: command descriptor to submit
1581  * @se_sess: associated se_sess for endpoint
1582  * @cdb: pointer to SCSI CDB
1583  * @sense: pointer to SCSI sense buffer
1584  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1585  * @data_length: fabric expected data transfer length
1586  * @task_attr: SAM task attribute
1587  * @data_dir: DMA data direction
1588  * @flags: flags for command submission from target_sc_flags_tables
1589  * @sgl: struct scatterlist memory for unidirectional mapping
1590  * @sgl_count: scatterlist count for unidirectional mapping
1591  * @sgl_bidi: struct scatterlist memory for bidirectional READ mapping
1592  * @sgl_bidi_count: scatterlist count for bidirectional READ mapping
1593  * @sgl_prot: struct scatterlist memory protection information
1594  * @sgl_prot_count: scatterlist count for protection information
1595  *
1596  * Task tags are supported if the caller has set @se_cmd->tag.
1597  *
1598  * Returns non zero to signal active I/O shutdown failure.  All other
1599  * setup exceptions will be returned as a SCSI CHECK_CONDITION response,
1600  * but still return zero here.
1601  *
1602  * This may only be called from process context, and also currently
1603  * assumes internal allocation of fabric payload buffer by target-core.
1604  */
1605 int target_submit_cmd_map_sgls(struct se_cmd *se_cmd, struct se_session *se_sess,
1606 		unsigned char *cdb, unsigned char *sense, u64 unpacked_lun,
1607 		u32 data_length, int task_attr, int data_dir, int flags,
1608 		struct scatterlist *sgl, u32 sgl_count,
1609 		struct scatterlist *sgl_bidi, u32 sgl_bidi_count,
1610 		struct scatterlist *sgl_prot, u32 sgl_prot_count)
1611 {
1612 	struct se_portal_group *se_tpg;
1613 	sense_reason_t rc;
1614 	int ret;
1615 
1616 	se_tpg = se_sess->se_tpg;
1617 	BUG_ON(!se_tpg);
1618 	BUG_ON(se_cmd->se_tfo || se_cmd->se_sess);
1619 	BUG_ON(in_interrupt());
1620 
1621 	if (flags & TARGET_SCF_USE_CPUID)
1622 		se_cmd->se_cmd_flags |= SCF_USE_CPUID;
1623 	/*
1624 	 * Initialize se_cmd for target operation.  From this point
1625 	 * exceptions are handled by sending exception status via
1626 	 * target_core_fabric_ops->queue_status() callback
1627 	 */
1628 	transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess,
1629 				data_length, data_dir, task_attr, sense,
1630 				unpacked_lun);
1631 
1632 	if (flags & TARGET_SCF_UNKNOWN_SIZE)
1633 		se_cmd->unknown_data_length = 1;
1634 	/*
1635 	 * Obtain struct se_cmd->cmd_kref reference. A second kref_get here is
1636 	 * necessary for fabrics using TARGET_SCF_ACK_KREF that expect a second
1637 	 * kref_put() to happen during fabric packet acknowledgement.
1638 	 */
1639 	ret = target_get_sess_cmd(se_cmd, flags & TARGET_SCF_ACK_KREF);
1640 	if (ret)
1641 		return ret;
1642 	/*
1643 	 * Signal bidirectional data payloads to target-core
1644 	 */
1645 	if (flags & TARGET_SCF_BIDI_OP)
1646 		se_cmd->se_cmd_flags |= SCF_BIDI;
1647 
1648 	rc = target_cmd_init_cdb(se_cmd, cdb);
1649 	if (rc) {
1650 		transport_send_check_condition_and_sense(se_cmd, rc, 0);
1651 		target_put_sess_cmd(se_cmd);
1652 		return 0;
1653 	}
1654 
1655 	/*
1656 	 * Locate se_lun pointer and attach it to struct se_cmd
1657 	 */
1658 	rc = transport_lookup_cmd_lun(se_cmd);
1659 	if (rc) {
1660 		transport_send_check_condition_and_sense(se_cmd, rc, 0);
1661 		target_put_sess_cmd(se_cmd);
1662 		return 0;
1663 	}
1664 
1665 	rc = target_cmd_parse_cdb(se_cmd);
1666 	if (rc != 0) {
1667 		transport_generic_request_failure(se_cmd, rc);
1668 		return 0;
1669 	}
1670 
1671 	/*
1672 	 * Save pointers for SGLs containing protection information,
1673 	 * if present.
1674 	 */
1675 	if (sgl_prot_count) {
1676 		se_cmd->t_prot_sg = sgl_prot;
1677 		se_cmd->t_prot_nents = sgl_prot_count;
1678 		se_cmd->se_cmd_flags |= SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC;
1679 	}
1680 
1681 	/*
1682 	 * When a non zero sgl_count has been passed perform SGL passthrough
1683 	 * mapping for pre-allocated fabric memory instead of having target
1684 	 * core perform an internal SGL allocation..
1685 	 */
1686 	if (sgl_count != 0) {
1687 		BUG_ON(!sgl);
1688 
1689 		/*
1690 		 * A work-around for tcm_loop as some userspace code via
1691 		 * scsi-generic do not memset their associated read buffers,
1692 		 * so go ahead and do that here for type non-data CDBs.  Also
1693 		 * note that this is currently guaranteed to be a single SGL
1694 		 * for this case by target core in target_setup_cmd_from_cdb()
1695 		 * -> transport_generic_cmd_sequencer().
1696 		 */
1697 		if (!(se_cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) &&
1698 		     se_cmd->data_direction == DMA_FROM_DEVICE) {
1699 			unsigned char *buf = NULL;
1700 
1701 			if (sgl)
1702 				buf = kmap(sg_page(sgl)) + sgl->offset;
1703 
1704 			if (buf) {
1705 				memset(buf, 0, sgl->length);
1706 				kunmap(sg_page(sgl));
1707 			}
1708 		}
1709 
1710 		rc = transport_generic_map_mem_to_cmd(se_cmd, sgl, sgl_count,
1711 				sgl_bidi, sgl_bidi_count);
1712 		if (rc != 0) {
1713 			transport_generic_request_failure(se_cmd, rc);
1714 			return 0;
1715 		}
1716 	}
1717 
1718 	/*
1719 	 * Check if we need to delay processing because of ALUA
1720 	 * Active/NonOptimized primary access state..
1721 	 */
1722 	core_alua_check_nonop_delay(se_cmd);
1723 
1724 	transport_handle_cdb_direct(se_cmd);
1725 	return 0;
1726 }
1727 EXPORT_SYMBOL(target_submit_cmd_map_sgls);
1728 
1729 /**
1730  * target_submit_cmd - lookup unpacked lun and submit uninitialized se_cmd
1731  *
1732  * @se_cmd: command descriptor to submit
1733  * @se_sess: associated se_sess for endpoint
1734  * @cdb: pointer to SCSI CDB
1735  * @sense: pointer to SCSI sense buffer
1736  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1737  * @data_length: fabric expected data transfer length
1738  * @task_attr: SAM task attribute
1739  * @data_dir: DMA data direction
1740  * @flags: flags for command submission from target_sc_flags_tables
1741  *
1742  * Task tags are supported if the caller has set @se_cmd->tag.
1743  *
1744  * Returns non zero to signal active I/O shutdown failure.  All other
1745  * setup exceptions will be returned as a SCSI CHECK_CONDITION response,
1746  * but still return zero here.
1747  *
1748  * This may only be called from process context, and also currently
1749  * assumes internal allocation of fabric payload buffer by target-core.
1750  *
1751  * It also assumes interal target core SGL memory allocation.
1752  */
1753 int target_submit_cmd(struct se_cmd *se_cmd, struct se_session *se_sess,
1754 		unsigned char *cdb, unsigned char *sense, u64 unpacked_lun,
1755 		u32 data_length, int task_attr, int data_dir, int flags)
1756 {
1757 	return target_submit_cmd_map_sgls(se_cmd, se_sess, cdb, sense,
1758 			unpacked_lun, data_length, task_attr, data_dir,
1759 			flags, NULL, 0, NULL, 0, NULL, 0);
1760 }
1761 EXPORT_SYMBOL(target_submit_cmd);
1762 
1763 static void target_complete_tmr_failure(struct work_struct *work)
1764 {
1765 	struct se_cmd *se_cmd = container_of(work, struct se_cmd, work);
1766 
1767 	se_cmd->se_tmr_req->response = TMR_LUN_DOES_NOT_EXIST;
1768 	se_cmd->se_tfo->queue_tm_rsp(se_cmd);
1769 
1770 	transport_lun_remove_cmd(se_cmd);
1771 	transport_cmd_check_stop_to_fabric(se_cmd);
1772 }
1773 
1774 /**
1775  * target_submit_tmr - lookup unpacked lun and submit uninitialized se_cmd
1776  *                     for TMR CDBs
1777  *
1778  * @se_cmd: command descriptor to submit
1779  * @se_sess: associated se_sess for endpoint
1780  * @sense: pointer to SCSI sense buffer
1781  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1782  * @fabric_tmr_ptr: fabric context for TMR req
1783  * @tm_type: Type of TM request
1784  * @gfp: gfp type for caller
1785  * @tag: referenced task tag for TMR_ABORT_TASK
1786  * @flags: submit cmd flags
1787  *
1788  * Callable from all contexts.
1789  **/
1790 
1791 int target_submit_tmr(struct se_cmd *se_cmd, struct se_session *se_sess,
1792 		unsigned char *sense, u64 unpacked_lun,
1793 		void *fabric_tmr_ptr, unsigned char tm_type,
1794 		gfp_t gfp, u64 tag, int flags)
1795 {
1796 	struct se_portal_group *se_tpg;
1797 	int ret;
1798 
1799 	se_tpg = se_sess->se_tpg;
1800 	BUG_ON(!se_tpg);
1801 
1802 	transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess,
1803 			      0, DMA_NONE, TCM_SIMPLE_TAG, sense, unpacked_lun);
1804 	/*
1805 	 * FIXME: Currently expect caller to handle se_cmd->se_tmr_req
1806 	 * allocation failure.
1807 	 */
1808 	ret = core_tmr_alloc_req(se_cmd, fabric_tmr_ptr, tm_type, gfp);
1809 	if (ret < 0)
1810 		return -ENOMEM;
1811 
1812 	if (tm_type == TMR_ABORT_TASK)
1813 		se_cmd->se_tmr_req->ref_task_tag = tag;
1814 
1815 	/* See target_submit_cmd for commentary */
1816 	ret = target_get_sess_cmd(se_cmd, flags & TARGET_SCF_ACK_KREF);
1817 	if (ret) {
1818 		core_tmr_release_req(se_cmd->se_tmr_req);
1819 		return ret;
1820 	}
1821 
1822 	ret = transport_lookup_tmr_lun(se_cmd);
1823 	if (ret)
1824 		goto failure;
1825 
1826 	transport_generic_handle_tmr(se_cmd);
1827 	return 0;
1828 
1829 	/*
1830 	 * For callback during failure handling, push this work off
1831 	 * to process context with TMR_LUN_DOES_NOT_EXIST status.
1832 	 */
1833 failure:
1834 	INIT_WORK(&se_cmd->work, target_complete_tmr_failure);
1835 	schedule_work(&se_cmd->work);
1836 	return 0;
1837 }
1838 EXPORT_SYMBOL(target_submit_tmr);
1839 
1840 /*
1841  * Handle SAM-esque emulation for generic transport request failures.
1842  */
1843 void transport_generic_request_failure(struct se_cmd *cmd,
1844 		sense_reason_t sense_reason)
1845 {
1846 	int ret = 0, post_ret;
1847 
1848 	pr_debug("-----[ Storage Engine Exception; sense_reason %d\n",
1849 		 sense_reason);
1850 	target_show_cmd("-----[ ", cmd);
1851 
1852 	/*
1853 	 * For SAM Task Attribute emulation for failed struct se_cmd
1854 	 */
1855 	transport_complete_task_attr(cmd);
1856 
1857 	if (cmd->transport_complete_callback)
1858 		cmd->transport_complete_callback(cmd, false, &post_ret);
1859 
1860 	if (cmd->transport_state & CMD_T_ABORTED) {
1861 		INIT_WORK(&cmd->work, target_abort_work);
1862 		queue_work(target_completion_wq, &cmd->work);
1863 		return;
1864 	}
1865 
1866 	switch (sense_reason) {
1867 	case TCM_NON_EXISTENT_LUN:
1868 	case TCM_UNSUPPORTED_SCSI_OPCODE:
1869 	case TCM_INVALID_CDB_FIELD:
1870 	case TCM_INVALID_PARAMETER_LIST:
1871 	case TCM_PARAMETER_LIST_LENGTH_ERROR:
1872 	case TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE:
1873 	case TCM_UNKNOWN_MODE_PAGE:
1874 	case TCM_WRITE_PROTECTED:
1875 	case TCM_ADDRESS_OUT_OF_RANGE:
1876 	case TCM_CHECK_CONDITION_ABORT_CMD:
1877 	case TCM_CHECK_CONDITION_UNIT_ATTENTION:
1878 	case TCM_CHECK_CONDITION_NOT_READY:
1879 	case TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED:
1880 	case TCM_LOGICAL_BLOCK_APP_TAG_CHECK_FAILED:
1881 	case TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED:
1882 	case TCM_COPY_TARGET_DEVICE_NOT_REACHABLE:
1883 	case TCM_TOO_MANY_TARGET_DESCS:
1884 	case TCM_UNSUPPORTED_TARGET_DESC_TYPE_CODE:
1885 	case TCM_TOO_MANY_SEGMENT_DESCS:
1886 	case TCM_UNSUPPORTED_SEGMENT_DESC_TYPE_CODE:
1887 		break;
1888 	case TCM_OUT_OF_RESOURCES:
1889 		cmd->scsi_status = SAM_STAT_TASK_SET_FULL;
1890 		goto queue_status;
1891 	case TCM_LUN_BUSY:
1892 		cmd->scsi_status = SAM_STAT_BUSY;
1893 		goto queue_status;
1894 	case TCM_RESERVATION_CONFLICT:
1895 		/*
1896 		 * No SENSE Data payload for this case, set SCSI Status
1897 		 * and queue the response to $FABRIC_MOD.
1898 		 *
1899 		 * Uses linux/include/scsi/scsi.h SAM status codes defs
1900 		 */
1901 		cmd->scsi_status = SAM_STAT_RESERVATION_CONFLICT;
1902 		/*
1903 		 * For UA Interlock Code 11b, a RESERVATION CONFLICT will
1904 		 * establish a UNIT ATTENTION with PREVIOUS RESERVATION
1905 		 * CONFLICT STATUS.
1906 		 *
1907 		 * See spc4r17, section 7.4.6 Control Mode Page, Table 349
1908 		 */
1909 		if (cmd->se_sess &&
1910 		    cmd->se_dev->dev_attrib.emulate_ua_intlck_ctrl
1911 					== TARGET_UA_INTLCK_CTRL_ESTABLISH_UA) {
1912 			target_ua_allocate_lun(cmd->se_sess->se_node_acl,
1913 					       cmd->orig_fe_lun, 0x2C,
1914 					ASCQ_2CH_PREVIOUS_RESERVATION_CONFLICT_STATUS);
1915 		}
1916 
1917 		goto queue_status;
1918 	default:
1919 		pr_err("Unknown transport error for CDB 0x%02x: %d\n",
1920 			cmd->t_task_cdb[0], sense_reason);
1921 		sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
1922 		break;
1923 	}
1924 
1925 	ret = transport_send_check_condition_and_sense(cmd, sense_reason, 0);
1926 	if (ret)
1927 		goto queue_full;
1928 
1929 check_stop:
1930 	transport_lun_remove_cmd(cmd);
1931 	transport_cmd_check_stop_to_fabric(cmd);
1932 	return;
1933 
1934 queue_status:
1935 	trace_target_cmd_complete(cmd);
1936 	ret = cmd->se_tfo->queue_status(cmd);
1937 	if (!ret)
1938 		goto check_stop;
1939 queue_full:
1940 	transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
1941 }
1942 EXPORT_SYMBOL(transport_generic_request_failure);
1943 
1944 void __target_execute_cmd(struct se_cmd *cmd, bool do_checks)
1945 {
1946 	sense_reason_t ret;
1947 
1948 	if (!cmd->execute_cmd) {
1949 		ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
1950 		goto err;
1951 	}
1952 	if (do_checks) {
1953 		/*
1954 		 * Check for an existing UNIT ATTENTION condition after
1955 		 * target_handle_task_attr() has done SAM task attr
1956 		 * checking, and possibly have already defered execution
1957 		 * out to target_restart_delayed_cmds() context.
1958 		 */
1959 		ret = target_scsi3_ua_check(cmd);
1960 		if (ret)
1961 			goto err;
1962 
1963 		ret = target_alua_state_check(cmd);
1964 		if (ret)
1965 			goto err;
1966 
1967 		ret = target_check_reservation(cmd);
1968 		if (ret) {
1969 			cmd->scsi_status = SAM_STAT_RESERVATION_CONFLICT;
1970 			goto err;
1971 		}
1972 	}
1973 
1974 	ret = cmd->execute_cmd(cmd);
1975 	if (!ret)
1976 		return;
1977 err:
1978 	spin_lock_irq(&cmd->t_state_lock);
1979 	cmd->transport_state &= ~CMD_T_SENT;
1980 	spin_unlock_irq(&cmd->t_state_lock);
1981 
1982 	transport_generic_request_failure(cmd, ret);
1983 }
1984 
1985 static int target_write_prot_action(struct se_cmd *cmd)
1986 {
1987 	u32 sectors;
1988 	/*
1989 	 * Perform WRITE_INSERT of PI using software emulation when backend
1990 	 * device has PI enabled, if the transport has not already generated
1991 	 * PI using hardware WRITE_INSERT offload.
1992 	 */
1993 	switch (cmd->prot_op) {
1994 	case TARGET_PROT_DOUT_INSERT:
1995 		if (!(cmd->se_sess->sup_prot_ops & TARGET_PROT_DOUT_INSERT))
1996 			sbc_dif_generate(cmd);
1997 		break;
1998 	case TARGET_PROT_DOUT_STRIP:
1999 		if (cmd->se_sess->sup_prot_ops & TARGET_PROT_DOUT_STRIP)
2000 			break;
2001 
2002 		sectors = cmd->data_length >> ilog2(cmd->se_dev->dev_attrib.block_size);
2003 		cmd->pi_err = sbc_dif_verify(cmd, cmd->t_task_lba,
2004 					     sectors, 0, cmd->t_prot_sg, 0);
2005 		if (unlikely(cmd->pi_err)) {
2006 			spin_lock_irq(&cmd->t_state_lock);
2007 			cmd->transport_state &= ~CMD_T_SENT;
2008 			spin_unlock_irq(&cmd->t_state_lock);
2009 			transport_generic_request_failure(cmd, cmd->pi_err);
2010 			return -1;
2011 		}
2012 		break;
2013 	default:
2014 		break;
2015 	}
2016 
2017 	return 0;
2018 }
2019 
2020 static bool target_handle_task_attr(struct se_cmd *cmd)
2021 {
2022 	struct se_device *dev = cmd->se_dev;
2023 
2024 	if (dev->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
2025 		return false;
2026 
2027 	cmd->se_cmd_flags |= SCF_TASK_ATTR_SET;
2028 
2029 	/*
2030 	 * Check for the existence of HEAD_OF_QUEUE, and if true return 1
2031 	 * to allow the passed struct se_cmd list of tasks to the front of the list.
2032 	 */
2033 	switch (cmd->sam_task_attr) {
2034 	case TCM_HEAD_TAG:
2035 		pr_debug("Added HEAD_OF_QUEUE for CDB: 0x%02x\n",
2036 			 cmd->t_task_cdb[0]);
2037 		return false;
2038 	case TCM_ORDERED_TAG:
2039 		atomic_inc_mb(&dev->dev_ordered_sync);
2040 
2041 		pr_debug("Added ORDERED for CDB: 0x%02x to ordered list\n",
2042 			 cmd->t_task_cdb[0]);
2043 
2044 		/*
2045 		 * Execute an ORDERED command if no other older commands
2046 		 * exist that need to be completed first.
2047 		 */
2048 		if (!atomic_read(&dev->simple_cmds))
2049 			return false;
2050 		break;
2051 	default:
2052 		/*
2053 		 * For SIMPLE and UNTAGGED Task Attribute commands
2054 		 */
2055 		atomic_inc_mb(&dev->simple_cmds);
2056 		break;
2057 	}
2058 
2059 	if (atomic_read(&dev->dev_ordered_sync) == 0)
2060 		return false;
2061 
2062 	spin_lock(&dev->delayed_cmd_lock);
2063 	list_add_tail(&cmd->se_delayed_node, &dev->delayed_cmd_list);
2064 	spin_unlock(&dev->delayed_cmd_lock);
2065 
2066 	pr_debug("Added CDB: 0x%02x Task Attr: 0x%02x to delayed CMD listn",
2067 		cmd->t_task_cdb[0], cmd->sam_task_attr);
2068 	return true;
2069 }
2070 
2071 void target_execute_cmd(struct se_cmd *cmd)
2072 {
2073 	/*
2074 	 * Determine if frontend context caller is requesting the stopping of
2075 	 * this command for frontend exceptions.
2076 	 *
2077 	 * If the received CDB has already been aborted stop processing it here.
2078 	 */
2079 	if (target_cmd_interrupted(cmd))
2080 		return;
2081 
2082 	spin_lock_irq(&cmd->t_state_lock);
2083 	cmd->t_state = TRANSPORT_PROCESSING;
2084 	cmd->transport_state |= CMD_T_ACTIVE | CMD_T_SENT;
2085 	spin_unlock_irq(&cmd->t_state_lock);
2086 
2087 	if (target_write_prot_action(cmd))
2088 		return;
2089 
2090 	if (target_handle_task_attr(cmd)) {
2091 		spin_lock_irq(&cmd->t_state_lock);
2092 		cmd->transport_state &= ~CMD_T_SENT;
2093 		spin_unlock_irq(&cmd->t_state_lock);
2094 		return;
2095 	}
2096 
2097 	__target_execute_cmd(cmd, true);
2098 }
2099 EXPORT_SYMBOL(target_execute_cmd);
2100 
2101 /*
2102  * Process all commands up to the last received ORDERED task attribute which
2103  * requires another blocking boundary
2104  */
2105 static void target_restart_delayed_cmds(struct se_device *dev)
2106 {
2107 	for (;;) {
2108 		struct se_cmd *cmd;
2109 
2110 		spin_lock(&dev->delayed_cmd_lock);
2111 		if (list_empty(&dev->delayed_cmd_list)) {
2112 			spin_unlock(&dev->delayed_cmd_lock);
2113 			break;
2114 		}
2115 
2116 		cmd = list_entry(dev->delayed_cmd_list.next,
2117 				 struct se_cmd, se_delayed_node);
2118 		list_del(&cmd->se_delayed_node);
2119 		spin_unlock(&dev->delayed_cmd_lock);
2120 
2121 		cmd->transport_state |= CMD_T_SENT;
2122 
2123 		__target_execute_cmd(cmd, true);
2124 
2125 		if (cmd->sam_task_attr == TCM_ORDERED_TAG)
2126 			break;
2127 	}
2128 }
2129 
2130 /*
2131  * Called from I/O completion to determine which dormant/delayed
2132  * and ordered cmds need to have their tasks added to the execution queue.
2133  */
2134 static void transport_complete_task_attr(struct se_cmd *cmd)
2135 {
2136 	struct se_device *dev = cmd->se_dev;
2137 
2138 	if (dev->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
2139 		return;
2140 
2141 	if (!(cmd->se_cmd_flags & SCF_TASK_ATTR_SET))
2142 		goto restart;
2143 
2144 	if (cmd->sam_task_attr == TCM_SIMPLE_TAG) {
2145 		atomic_dec_mb(&dev->simple_cmds);
2146 		dev->dev_cur_ordered_id++;
2147 	} else if (cmd->sam_task_attr == TCM_HEAD_TAG) {
2148 		dev->dev_cur_ordered_id++;
2149 		pr_debug("Incremented dev_cur_ordered_id: %u for HEAD_OF_QUEUE\n",
2150 			 dev->dev_cur_ordered_id);
2151 	} else if (cmd->sam_task_attr == TCM_ORDERED_TAG) {
2152 		atomic_dec_mb(&dev->dev_ordered_sync);
2153 
2154 		dev->dev_cur_ordered_id++;
2155 		pr_debug("Incremented dev_cur_ordered_id: %u for ORDERED\n",
2156 			 dev->dev_cur_ordered_id);
2157 	}
2158 	cmd->se_cmd_flags &= ~SCF_TASK_ATTR_SET;
2159 
2160 restart:
2161 	target_restart_delayed_cmds(dev);
2162 }
2163 
2164 static void transport_complete_qf(struct se_cmd *cmd)
2165 {
2166 	int ret = 0;
2167 
2168 	transport_complete_task_attr(cmd);
2169 	/*
2170 	 * If a fabric driver ->write_pending() or ->queue_data_in() callback
2171 	 * has returned neither -ENOMEM or -EAGAIN, assume it's fatal and
2172 	 * the same callbacks should not be retried.  Return CHECK_CONDITION
2173 	 * if a scsi_status is not already set.
2174 	 *
2175 	 * If a fabric driver ->queue_status() has returned non zero, always
2176 	 * keep retrying no matter what..
2177 	 */
2178 	if (cmd->t_state == TRANSPORT_COMPLETE_QF_ERR) {
2179 		if (cmd->scsi_status)
2180 			goto queue_status;
2181 
2182 		translate_sense_reason(cmd, TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE);
2183 		goto queue_status;
2184 	}
2185 
2186 	/*
2187 	 * Check if we need to send a sense buffer from
2188 	 * the struct se_cmd in question. We do NOT want
2189 	 * to take this path of the IO has been marked as
2190 	 * needing to be treated like a "normal read". This
2191 	 * is the case if it's a tape read, and either the
2192 	 * FM, EOM, or ILI bits are set, but there is no
2193 	 * sense data.
2194 	 */
2195 	if (!(cmd->se_cmd_flags & SCF_TREAT_READ_AS_NORMAL) &&
2196 	    cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE)
2197 		goto queue_status;
2198 
2199 	switch (cmd->data_direction) {
2200 	case DMA_FROM_DEVICE:
2201 		/* queue status if not treating this as a normal read */
2202 		if (cmd->scsi_status &&
2203 		    !(cmd->se_cmd_flags & SCF_TREAT_READ_AS_NORMAL))
2204 			goto queue_status;
2205 
2206 		trace_target_cmd_complete(cmd);
2207 		ret = cmd->se_tfo->queue_data_in(cmd);
2208 		break;
2209 	case DMA_TO_DEVICE:
2210 		if (cmd->se_cmd_flags & SCF_BIDI) {
2211 			ret = cmd->se_tfo->queue_data_in(cmd);
2212 			break;
2213 		}
2214 		fallthrough;
2215 	case DMA_NONE:
2216 queue_status:
2217 		trace_target_cmd_complete(cmd);
2218 		ret = cmd->se_tfo->queue_status(cmd);
2219 		break;
2220 	default:
2221 		break;
2222 	}
2223 
2224 	if (ret < 0) {
2225 		transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
2226 		return;
2227 	}
2228 	transport_lun_remove_cmd(cmd);
2229 	transport_cmd_check_stop_to_fabric(cmd);
2230 }
2231 
2232 static void transport_handle_queue_full(struct se_cmd *cmd, struct se_device *dev,
2233 					int err, bool write_pending)
2234 {
2235 	/*
2236 	 * -EAGAIN or -ENOMEM signals retry of ->write_pending() and/or
2237 	 * ->queue_data_in() callbacks from new process context.
2238 	 *
2239 	 * Otherwise for other errors, transport_complete_qf() will send
2240 	 * CHECK_CONDITION via ->queue_status() instead of attempting to
2241 	 * retry associated fabric driver data-transfer callbacks.
2242 	 */
2243 	if (err == -EAGAIN || err == -ENOMEM) {
2244 		cmd->t_state = (write_pending) ? TRANSPORT_COMPLETE_QF_WP :
2245 						 TRANSPORT_COMPLETE_QF_OK;
2246 	} else {
2247 		pr_warn_ratelimited("Got unknown fabric queue status: %d\n", err);
2248 		cmd->t_state = TRANSPORT_COMPLETE_QF_ERR;
2249 	}
2250 
2251 	spin_lock_irq(&dev->qf_cmd_lock);
2252 	list_add_tail(&cmd->se_qf_node, &cmd->se_dev->qf_cmd_list);
2253 	atomic_inc_mb(&dev->dev_qf_count);
2254 	spin_unlock_irq(&cmd->se_dev->qf_cmd_lock);
2255 
2256 	schedule_work(&cmd->se_dev->qf_work_queue);
2257 }
2258 
2259 static bool target_read_prot_action(struct se_cmd *cmd)
2260 {
2261 	switch (cmd->prot_op) {
2262 	case TARGET_PROT_DIN_STRIP:
2263 		if (!(cmd->se_sess->sup_prot_ops & TARGET_PROT_DIN_STRIP)) {
2264 			u32 sectors = cmd->data_length >>
2265 				  ilog2(cmd->se_dev->dev_attrib.block_size);
2266 
2267 			cmd->pi_err = sbc_dif_verify(cmd, cmd->t_task_lba,
2268 						     sectors, 0, cmd->t_prot_sg,
2269 						     0);
2270 			if (cmd->pi_err)
2271 				return true;
2272 		}
2273 		break;
2274 	case TARGET_PROT_DIN_INSERT:
2275 		if (cmd->se_sess->sup_prot_ops & TARGET_PROT_DIN_INSERT)
2276 			break;
2277 
2278 		sbc_dif_generate(cmd);
2279 		break;
2280 	default:
2281 		break;
2282 	}
2283 
2284 	return false;
2285 }
2286 
2287 static void target_complete_ok_work(struct work_struct *work)
2288 {
2289 	struct se_cmd *cmd = container_of(work, struct se_cmd, work);
2290 	int ret;
2291 
2292 	/*
2293 	 * Check if we need to move delayed/dormant tasks from cmds on the
2294 	 * delayed execution list after a HEAD_OF_QUEUE or ORDERED Task
2295 	 * Attribute.
2296 	 */
2297 	transport_complete_task_attr(cmd);
2298 
2299 	/*
2300 	 * Check to schedule QUEUE_FULL work, or execute an existing
2301 	 * cmd->transport_qf_callback()
2302 	 */
2303 	if (atomic_read(&cmd->se_dev->dev_qf_count) != 0)
2304 		schedule_work(&cmd->se_dev->qf_work_queue);
2305 
2306 	/*
2307 	 * Check if we need to send a sense buffer from
2308 	 * the struct se_cmd in question. We do NOT want
2309 	 * to take this path of the IO has been marked as
2310 	 * needing to be treated like a "normal read". This
2311 	 * is the case if it's a tape read, and either the
2312 	 * FM, EOM, or ILI bits are set, but there is no
2313 	 * sense data.
2314 	 */
2315 	if (!(cmd->se_cmd_flags & SCF_TREAT_READ_AS_NORMAL) &&
2316 	    cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) {
2317 		WARN_ON(!cmd->scsi_status);
2318 		ret = transport_send_check_condition_and_sense(
2319 					cmd, 0, 1);
2320 		if (ret)
2321 			goto queue_full;
2322 
2323 		transport_lun_remove_cmd(cmd);
2324 		transport_cmd_check_stop_to_fabric(cmd);
2325 		return;
2326 	}
2327 	/*
2328 	 * Check for a callback, used by amongst other things
2329 	 * XDWRITE_READ_10 and COMPARE_AND_WRITE emulation.
2330 	 */
2331 	if (cmd->transport_complete_callback) {
2332 		sense_reason_t rc;
2333 		bool caw = (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE);
2334 		bool zero_dl = !(cmd->data_length);
2335 		int post_ret = 0;
2336 
2337 		rc = cmd->transport_complete_callback(cmd, true, &post_ret);
2338 		if (!rc && !post_ret) {
2339 			if (caw && zero_dl)
2340 				goto queue_rsp;
2341 
2342 			return;
2343 		} else if (rc) {
2344 			ret = transport_send_check_condition_and_sense(cmd,
2345 						rc, 0);
2346 			if (ret)
2347 				goto queue_full;
2348 
2349 			transport_lun_remove_cmd(cmd);
2350 			transport_cmd_check_stop_to_fabric(cmd);
2351 			return;
2352 		}
2353 	}
2354 
2355 queue_rsp:
2356 	switch (cmd->data_direction) {
2357 	case DMA_FROM_DEVICE:
2358 		/*
2359 		 * if this is a READ-type IO, but SCSI status
2360 		 * is set, then skip returning data and just
2361 		 * return the status -- unless this IO is marked
2362 		 * as needing to be treated as a normal read,
2363 		 * in which case we want to go ahead and return
2364 		 * the data. This happens, for example, for tape
2365 		 * reads with the FM, EOM, or ILI bits set, with
2366 		 * no sense data.
2367 		 */
2368 		if (cmd->scsi_status &&
2369 		    !(cmd->se_cmd_flags & SCF_TREAT_READ_AS_NORMAL))
2370 			goto queue_status;
2371 
2372 		atomic_long_add(cmd->data_length,
2373 				&cmd->se_lun->lun_stats.tx_data_octets);
2374 		/*
2375 		 * Perform READ_STRIP of PI using software emulation when
2376 		 * backend had PI enabled, if the transport will not be
2377 		 * performing hardware READ_STRIP offload.
2378 		 */
2379 		if (target_read_prot_action(cmd)) {
2380 			ret = transport_send_check_condition_and_sense(cmd,
2381 						cmd->pi_err, 0);
2382 			if (ret)
2383 				goto queue_full;
2384 
2385 			transport_lun_remove_cmd(cmd);
2386 			transport_cmd_check_stop_to_fabric(cmd);
2387 			return;
2388 		}
2389 
2390 		trace_target_cmd_complete(cmd);
2391 		ret = cmd->se_tfo->queue_data_in(cmd);
2392 		if (ret)
2393 			goto queue_full;
2394 		break;
2395 	case DMA_TO_DEVICE:
2396 		atomic_long_add(cmd->data_length,
2397 				&cmd->se_lun->lun_stats.rx_data_octets);
2398 		/*
2399 		 * Check if we need to send READ payload for BIDI-COMMAND
2400 		 */
2401 		if (cmd->se_cmd_flags & SCF_BIDI) {
2402 			atomic_long_add(cmd->data_length,
2403 					&cmd->se_lun->lun_stats.tx_data_octets);
2404 			ret = cmd->se_tfo->queue_data_in(cmd);
2405 			if (ret)
2406 				goto queue_full;
2407 			break;
2408 		}
2409 		fallthrough;
2410 	case DMA_NONE:
2411 queue_status:
2412 		trace_target_cmd_complete(cmd);
2413 		ret = cmd->se_tfo->queue_status(cmd);
2414 		if (ret)
2415 			goto queue_full;
2416 		break;
2417 	default:
2418 		break;
2419 	}
2420 
2421 	transport_lun_remove_cmd(cmd);
2422 	transport_cmd_check_stop_to_fabric(cmd);
2423 	return;
2424 
2425 queue_full:
2426 	pr_debug("Handling complete_ok QUEUE_FULL: se_cmd: %p,"
2427 		" data_direction: %d\n", cmd, cmd->data_direction);
2428 
2429 	transport_handle_queue_full(cmd, cmd->se_dev, ret, false);
2430 }
2431 
2432 void target_free_sgl(struct scatterlist *sgl, int nents)
2433 {
2434 	sgl_free_n_order(sgl, nents, 0);
2435 }
2436 EXPORT_SYMBOL(target_free_sgl);
2437 
2438 static inline void transport_reset_sgl_orig(struct se_cmd *cmd)
2439 {
2440 	/*
2441 	 * Check for saved t_data_sg that may be used for COMPARE_AND_WRITE
2442 	 * emulation, and free + reset pointers if necessary..
2443 	 */
2444 	if (!cmd->t_data_sg_orig)
2445 		return;
2446 
2447 	kfree(cmd->t_data_sg);
2448 	cmd->t_data_sg = cmd->t_data_sg_orig;
2449 	cmd->t_data_sg_orig = NULL;
2450 	cmd->t_data_nents = cmd->t_data_nents_orig;
2451 	cmd->t_data_nents_orig = 0;
2452 }
2453 
2454 static inline void transport_free_pages(struct se_cmd *cmd)
2455 {
2456 	if (!(cmd->se_cmd_flags & SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC)) {
2457 		target_free_sgl(cmd->t_prot_sg, cmd->t_prot_nents);
2458 		cmd->t_prot_sg = NULL;
2459 		cmd->t_prot_nents = 0;
2460 	}
2461 
2462 	if (cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) {
2463 		/*
2464 		 * Release special case READ buffer payload required for
2465 		 * SG_TO_MEM_NOALLOC to function with COMPARE_AND_WRITE
2466 		 */
2467 		if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) {
2468 			target_free_sgl(cmd->t_bidi_data_sg,
2469 					   cmd->t_bidi_data_nents);
2470 			cmd->t_bidi_data_sg = NULL;
2471 			cmd->t_bidi_data_nents = 0;
2472 		}
2473 		transport_reset_sgl_orig(cmd);
2474 		return;
2475 	}
2476 	transport_reset_sgl_orig(cmd);
2477 
2478 	target_free_sgl(cmd->t_data_sg, cmd->t_data_nents);
2479 	cmd->t_data_sg = NULL;
2480 	cmd->t_data_nents = 0;
2481 
2482 	target_free_sgl(cmd->t_bidi_data_sg, cmd->t_bidi_data_nents);
2483 	cmd->t_bidi_data_sg = NULL;
2484 	cmd->t_bidi_data_nents = 0;
2485 }
2486 
2487 void *transport_kmap_data_sg(struct se_cmd *cmd)
2488 {
2489 	struct scatterlist *sg = cmd->t_data_sg;
2490 	struct page **pages;
2491 	int i;
2492 
2493 	/*
2494 	 * We need to take into account a possible offset here for fabrics like
2495 	 * tcm_loop who may be using a contig buffer from the SCSI midlayer for
2496 	 * control CDBs passed as SGLs via transport_generic_map_mem_to_cmd()
2497 	 */
2498 	if (!cmd->t_data_nents)
2499 		return NULL;
2500 
2501 	BUG_ON(!sg);
2502 	if (cmd->t_data_nents == 1)
2503 		return kmap(sg_page(sg)) + sg->offset;
2504 
2505 	/* >1 page. use vmap */
2506 	pages = kmalloc_array(cmd->t_data_nents, sizeof(*pages), GFP_KERNEL);
2507 	if (!pages)
2508 		return NULL;
2509 
2510 	/* convert sg[] to pages[] */
2511 	for_each_sg(cmd->t_data_sg, sg, cmd->t_data_nents, i) {
2512 		pages[i] = sg_page(sg);
2513 	}
2514 
2515 	cmd->t_data_vmap = vmap(pages, cmd->t_data_nents,  VM_MAP, PAGE_KERNEL);
2516 	kfree(pages);
2517 	if (!cmd->t_data_vmap)
2518 		return NULL;
2519 
2520 	return cmd->t_data_vmap + cmd->t_data_sg[0].offset;
2521 }
2522 EXPORT_SYMBOL(transport_kmap_data_sg);
2523 
2524 void transport_kunmap_data_sg(struct se_cmd *cmd)
2525 {
2526 	if (!cmd->t_data_nents) {
2527 		return;
2528 	} else if (cmd->t_data_nents == 1) {
2529 		kunmap(sg_page(cmd->t_data_sg));
2530 		return;
2531 	}
2532 
2533 	vunmap(cmd->t_data_vmap);
2534 	cmd->t_data_vmap = NULL;
2535 }
2536 EXPORT_SYMBOL(transport_kunmap_data_sg);
2537 
2538 int
2539 target_alloc_sgl(struct scatterlist **sgl, unsigned int *nents, u32 length,
2540 		 bool zero_page, bool chainable)
2541 {
2542 	gfp_t gfp = GFP_KERNEL | (zero_page ? __GFP_ZERO : 0);
2543 
2544 	*sgl = sgl_alloc_order(length, 0, chainable, gfp, nents);
2545 	return *sgl ? 0 : -ENOMEM;
2546 }
2547 EXPORT_SYMBOL(target_alloc_sgl);
2548 
2549 /*
2550  * Allocate any required resources to execute the command.  For writes we
2551  * might not have the payload yet, so notify the fabric via a call to
2552  * ->write_pending instead. Otherwise place it on the execution queue.
2553  */
2554 sense_reason_t
2555 transport_generic_new_cmd(struct se_cmd *cmd)
2556 {
2557 	unsigned long flags;
2558 	int ret = 0;
2559 	bool zero_flag = !(cmd->se_cmd_flags & SCF_SCSI_DATA_CDB);
2560 
2561 	if (cmd->prot_op != TARGET_PROT_NORMAL &&
2562 	    !(cmd->se_cmd_flags & SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC)) {
2563 		ret = target_alloc_sgl(&cmd->t_prot_sg, &cmd->t_prot_nents,
2564 				       cmd->prot_length, true, false);
2565 		if (ret < 0)
2566 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2567 	}
2568 
2569 	/*
2570 	 * Determine if the TCM fabric module has already allocated physical
2571 	 * memory, and is directly calling transport_generic_map_mem_to_cmd()
2572 	 * beforehand.
2573 	 */
2574 	if (!(cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) &&
2575 	    cmd->data_length) {
2576 
2577 		if ((cmd->se_cmd_flags & SCF_BIDI) ||
2578 		    (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE)) {
2579 			u32 bidi_length;
2580 
2581 			if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE)
2582 				bidi_length = cmd->t_task_nolb *
2583 					      cmd->se_dev->dev_attrib.block_size;
2584 			else
2585 				bidi_length = cmd->data_length;
2586 
2587 			ret = target_alloc_sgl(&cmd->t_bidi_data_sg,
2588 					       &cmd->t_bidi_data_nents,
2589 					       bidi_length, zero_flag, false);
2590 			if (ret < 0)
2591 				return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2592 		}
2593 
2594 		ret = target_alloc_sgl(&cmd->t_data_sg, &cmd->t_data_nents,
2595 				       cmd->data_length, zero_flag, false);
2596 		if (ret < 0)
2597 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2598 	} else if ((cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) &&
2599 		    cmd->data_length) {
2600 		/*
2601 		 * Special case for COMPARE_AND_WRITE with fabrics
2602 		 * using SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC.
2603 		 */
2604 		u32 caw_length = cmd->t_task_nolb *
2605 				 cmd->se_dev->dev_attrib.block_size;
2606 
2607 		ret = target_alloc_sgl(&cmd->t_bidi_data_sg,
2608 				       &cmd->t_bidi_data_nents,
2609 				       caw_length, zero_flag, false);
2610 		if (ret < 0)
2611 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2612 	}
2613 	/*
2614 	 * If this command is not a write we can execute it right here,
2615 	 * for write buffers we need to notify the fabric driver first
2616 	 * and let it call back once the write buffers are ready.
2617 	 */
2618 	target_add_to_state_list(cmd);
2619 	if (cmd->data_direction != DMA_TO_DEVICE || cmd->data_length == 0) {
2620 		target_execute_cmd(cmd);
2621 		return 0;
2622 	}
2623 
2624 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2625 	cmd->t_state = TRANSPORT_WRITE_PENDING;
2626 	/*
2627 	 * Determine if frontend context caller is requesting the stopping of
2628 	 * this command for frontend exceptions.
2629 	 */
2630 	if (cmd->transport_state & CMD_T_STOP &&
2631 	    !cmd->se_tfo->write_pending_must_be_called) {
2632 		pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08llx\n",
2633 			 __func__, __LINE__, cmd->tag);
2634 
2635 		spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2636 
2637 		complete_all(&cmd->t_transport_stop_comp);
2638 		return 0;
2639 	}
2640 	cmd->transport_state &= ~CMD_T_ACTIVE;
2641 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2642 
2643 	ret = cmd->se_tfo->write_pending(cmd);
2644 	if (ret)
2645 		goto queue_full;
2646 
2647 	return 0;
2648 
2649 queue_full:
2650 	pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n", cmd);
2651 	transport_handle_queue_full(cmd, cmd->se_dev, ret, true);
2652 	return 0;
2653 }
2654 EXPORT_SYMBOL(transport_generic_new_cmd);
2655 
2656 static void transport_write_pending_qf(struct se_cmd *cmd)
2657 {
2658 	unsigned long flags;
2659 	int ret;
2660 	bool stop;
2661 
2662 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2663 	stop = (cmd->transport_state & (CMD_T_STOP | CMD_T_ABORTED));
2664 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2665 
2666 	if (stop) {
2667 		pr_debug("%s:%d CMD_T_STOP|CMD_T_ABORTED for ITT: 0x%08llx\n",
2668 			__func__, __LINE__, cmd->tag);
2669 		complete_all(&cmd->t_transport_stop_comp);
2670 		return;
2671 	}
2672 
2673 	ret = cmd->se_tfo->write_pending(cmd);
2674 	if (ret) {
2675 		pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n",
2676 			 cmd);
2677 		transport_handle_queue_full(cmd, cmd->se_dev, ret, true);
2678 	}
2679 }
2680 
2681 static bool
2682 __transport_wait_for_tasks(struct se_cmd *, bool, bool *, bool *,
2683 			   unsigned long *flags);
2684 
2685 static void target_wait_free_cmd(struct se_cmd *cmd, bool *aborted, bool *tas)
2686 {
2687 	unsigned long flags;
2688 
2689 	spin_lock_irqsave(&cmd->t_state_lock, flags);
2690 	__transport_wait_for_tasks(cmd, true, aborted, tas, &flags);
2691 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2692 }
2693 
2694 /*
2695  * Call target_put_sess_cmd() and wait until target_release_cmd_kref(@cmd) has
2696  * finished.
2697  */
2698 void target_put_cmd_and_wait(struct se_cmd *cmd)
2699 {
2700 	DECLARE_COMPLETION_ONSTACK(compl);
2701 
2702 	WARN_ON_ONCE(cmd->abrt_compl);
2703 	cmd->abrt_compl = &compl;
2704 	target_put_sess_cmd(cmd);
2705 	wait_for_completion(&compl);
2706 }
2707 
2708 /*
2709  * This function is called by frontend drivers after processing of a command
2710  * has finished.
2711  *
2712  * The protocol for ensuring that either the regular frontend command
2713  * processing flow or target_handle_abort() code drops one reference is as
2714  * follows:
2715  * - Calling .queue_data_in(), .queue_status() or queue_tm_rsp() will cause
2716  *   the frontend driver to call this function synchronously or asynchronously.
2717  *   That will cause one reference to be dropped.
2718  * - During regular command processing the target core sets CMD_T_COMPLETE
2719  *   before invoking one of the .queue_*() functions.
2720  * - The code that aborts commands skips commands and TMFs for which
2721  *   CMD_T_COMPLETE has been set.
2722  * - CMD_T_ABORTED is set atomically after the CMD_T_COMPLETE check for
2723  *   commands that will be aborted.
2724  * - If the CMD_T_ABORTED flag is set but CMD_T_TAS has not been set
2725  *   transport_generic_free_cmd() skips its call to target_put_sess_cmd().
2726  * - For aborted commands for which CMD_T_TAS has been set .queue_status() will
2727  *   be called and will drop a reference.
2728  * - For aborted commands for which CMD_T_TAS has not been set .aborted_task()
2729  *   will be called. target_handle_abort() will drop the final reference.
2730  */
2731 int transport_generic_free_cmd(struct se_cmd *cmd, int wait_for_tasks)
2732 {
2733 	DECLARE_COMPLETION_ONSTACK(compl);
2734 	int ret = 0;
2735 	bool aborted = false, tas = false;
2736 
2737 	if (wait_for_tasks)
2738 		target_wait_free_cmd(cmd, &aborted, &tas);
2739 
2740 	if (cmd->se_cmd_flags & SCF_SE_LUN_CMD) {
2741 		/*
2742 		 * Handle WRITE failure case where transport_generic_new_cmd()
2743 		 * has already added se_cmd to state_list, but fabric has
2744 		 * failed command before I/O submission.
2745 		 */
2746 		if (cmd->state_active)
2747 			target_remove_from_state_list(cmd);
2748 
2749 		if (cmd->se_lun)
2750 			transport_lun_remove_cmd(cmd);
2751 	}
2752 	if (aborted)
2753 		cmd->free_compl = &compl;
2754 	ret = target_put_sess_cmd(cmd);
2755 	if (aborted) {
2756 		pr_debug("Detected CMD_T_ABORTED for ITT: %llu\n", cmd->tag);
2757 		wait_for_completion(&compl);
2758 		ret = 1;
2759 	}
2760 	return ret;
2761 }
2762 EXPORT_SYMBOL(transport_generic_free_cmd);
2763 
2764 /**
2765  * target_get_sess_cmd - Verify the session is accepting cmds and take ref
2766  * @se_cmd:	command descriptor to add
2767  * @ack_kref:	Signal that fabric will perform an ack target_put_sess_cmd()
2768  */
2769 int target_get_sess_cmd(struct se_cmd *se_cmd, bool ack_kref)
2770 {
2771 	struct se_session *se_sess = se_cmd->se_sess;
2772 	int ret = 0;
2773 
2774 	/*
2775 	 * Add a second kref if the fabric caller is expecting to handle
2776 	 * fabric acknowledgement that requires two target_put_sess_cmd()
2777 	 * invocations before se_cmd descriptor release.
2778 	 */
2779 	if (ack_kref) {
2780 		if (!kref_get_unless_zero(&se_cmd->cmd_kref))
2781 			return -EINVAL;
2782 
2783 		se_cmd->se_cmd_flags |= SCF_ACK_KREF;
2784 	}
2785 
2786 	if (!percpu_ref_tryget_live(&se_sess->cmd_count))
2787 		ret = -ESHUTDOWN;
2788 
2789 	if (ret && ack_kref)
2790 		target_put_sess_cmd(se_cmd);
2791 
2792 	return ret;
2793 }
2794 EXPORT_SYMBOL(target_get_sess_cmd);
2795 
2796 static void target_free_cmd_mem(struct se_cmd *cmd)
2797 {
2798 	transport_free_pages(cmd);
2799 
2800 	if (cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
2801 		core_tmr_release_req(cmd->se_tmr_req);
2802 	if (cmd->t_task_cdb != cmd->__t_task_cdb)
2803 		kfree(cmd->t_task_cdb);
2804 }
2805 
2806 static void target_release_cmd_kref(struct kref *kref)
2807 {
2808 	struct se_cmd *se_cmd = container_of(kref, struct se_cmd, cmd_kref);
2809 	struct se_session *se_sess = se_cmd->se_sess;
2810 	struct completion *free_compl = se_cmd->free_compl;
2811 	struct completion *abrt_compl = se_cmd->abrt_compl;
2812 
2813 	target_free_cmd_mem(se_cmd);
2814 	se_cmd->se_tfo->release_cmd(se_cmd);
2815 	if (free_compl)
2816 		complete(free_compl);
2817 	if (abrt_compl)
2818 		complete(abrt_compl);
2819 
2820 	percpu_ref_put(&se_sess->cmd_count);
2821 }
2822 
2823 /**
2824  * target_put_sess_cmd - decrease the command reference count
2825  * @se_cmd:	command to drop a reference from
2826  *
2827  * Returns 1 if and only if this target_put_sess_cmd() call caused the
2828  * refcount to drop to zero. Returns zero otherwise.
2829  */
2830 int target_put_sess_cmd(struct se_cmd *se_cmd)
2831 {
2832 	return kref_put(&se_cmd->cmd_kref, target_release_cmd_kref);
2833 }
2834 EXPORT_SYMBOL(target_put_sess_cmd);
2835 
2836 static const char *data_dir_name(enum dma_data_direction d)
2837 {
2838 	switch (d) {
2839 	case DMA_BIDIRECTIONAL:	return "BIDI";
2840 	case DMA_TO_DEVICE:	return "WRITE";
2841 	case DMA_FROM_DEVICE:	return "READ";
2842 	case DMA_NONE:		return "NONE";
2843 	}
2844 
2845 	return "(?)";
2846 }
2847 
2848 static const char *cmd_state_name(enum transport_state_table t)
2849 {
2850 	switch (t) {
2851 	case TRANSPORT_NO_STATE:	return "NO_STATE";
2852 	case TRANSPORT_NEW_CMD:		return "NEW_CMD";
2853 	case TRANSPORT_WRITE_PENDING:	return "WRITE_PENDING";
2854 	case TRANSPORT_PROCESSING:	return "PROCESSING";
2855 	case TRANSPORT_COMPLETE:	return "COMPLETE";
2856 	case TRANSPORT_ISTATE_PROCESSING:
2857 					return "ISTATE_PROCESSING";
2858 	case TRANSPORT_COMPLETE_QF_WP:	return "COMPLETE_QF_WP";
2859 	case TRANSPORT_COMPLETE_QF_OK:	return "COMPLETE_QF_OK";
2860 	case TRANSPORT_COMPLETE_QF_ERR:	return "COMPLETE_QF_ERR";
2861 	}
2862 
2863 	return "(?)";
2864 }
2865 
2866 static void target_append_str(char **str, const char *txt)
2867 {
2868 	char *prev = *str;
2869 
2870 	*str = *str ? kasprintf(GFP_ATOMIC, "%s,%s", *str, txt) :
2871 		kstrdup(txt, GFP_ATOMIC);
2872 	kfree(prev);
2873 }
2874 
2875 /*
2876  * Convert a transport state bitmask into a string. The caller is
2877  * responsible for freeing the returned pointer.
2878  */
2879 static char *target_ts_to_str(u32 ts)
2880 {
2881 	char *str = NULL;
2882 
2883 	if (ts & CMD_T_ABORTED)
2884 		target_append_str(&str, "aborted");
2885 	if (ts & CMD_T_ACTIVE)
2886 		target_append_str(&str, "active");
2887 	if (ts & CMD_T_COMPLETE)
2888 		target_append_str(&str, "complete");
2889 	if (ts & CMD_T_SENT)
2890 		target_append_str(&str, "sent");
2891 	if (ts & CMD_T_STOP)
2892 		target_append_str(&str, "stop");
2893 	if (ts & CMD_T_FABRIC_STOP)
2894 		target_append_str(&str, "fabric_stop");
2895 
2896 	return str;
2897 }
2898 
2899 static const char *target_tmf_name(enum tcm_tmreq_table tmf)
2900 {
2901 	switch (tmf) {
2902 	case TMR_ABORT_TASK:		return "ABORT_TASK";
2903 	case TMR_ABORT_TASK_SET:	return "ABORT_TASK_SET";
2904 	case TMR_CLEAR_ACA:		return "CLEAR_ACA";
2905 	case TMR_CLEAR_TASK_SET:	return "CLEAR_TASK_SET";
2906 	case TMR_LUN_RESET:		return "LUN_RESET";
2907 	case TMR_TARGET_WARM_RESET:	return "TARGET_WARM_RESET";
2908 	case TMR_TARGET_COLD_RESET:	return "TARGET_COLD_RESET";
2909 	case TMR_LUN_RESET_PRO:		return "LUN_RESET_PRO";
2910 	case TMR_UNKNOWN:		break;
2911 	}
2912 	return "(?)";
2913 }
2914 
2915 void target_show_cmd(const char *pfx, struct se_cmd *cmd)
2916 {
2917 	char *ts_str = target_ts_to_str(cmd->transport_state);
2918 	const u8 *cdb = cmd->t_task_cdb;
2919 	struct se_tmr_req *tmf = cmd->se_tmr_req;
2920 
2921 	if (!(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)) {
2922 		pr_debug("%scmd %#02x:%#02x with tag %#llx dir %s i_state %d t_state %s len %d refcnt %d transport_state %s\n",
2923 			 pfx, cdb[0], cdb[1], cmd->tag,
2924 			 data_dir_name(cmd->data_direction),
2925 			 cmd->se_tfo->get_cmd_state(cmd),
2926 			 cmd_state_name(cmd->t_state), cmd->data_length,
2927 			 kref_read(&cmd->cmd_kref), ts_str);
2928 	} else {
2929 		pr_debug("%stmf %s with tag %#llx ref_task_tag %#llx i_state %d t_state %s refcnt %d transport_state %s\n",
2930 			 pfx, target_tmf_name(tmf->function), cmd->tag,
2931 			 tmf->ref_task_tag, cmd->se_tfo->get_cmd_state(cmd),
2932 			 cmd_state_name(cmd->t_state),
2933 			 kref_read(&cmd->cmd_kref), ts_str);
2934 	}
2935 	kfree(ts_str);
2936 }
2937 EXPORT_SYMBOL(target_show_cmd);
2938 
2939 static void target_stop_session_confirm(struct percpu_ref *ref)
2940 {
2941 	struct se_session *se_sess = container_of(ref, struct se_session,
2942 						  cmd_count);
2943 	complete_all(&se_sess->stop_done);
2944 }
2945 
2946 /**
2947  * target_stop_session - Stop new IO from being queued on the session.
2948  * @se_sess:    session to stop
2949  */
2950 void target_stop_session(struct se_session *se_sess)
2951 {
2952 	pr_debug("Stopping session queue.\n");
2953 	if (atomic_cmpxchg(&se_sess->stopped, 0, 1) == 0)
2954 		percpu_ref_kill_and_confirm(&se_sess->cmd_count,
2955 					    target_stop_session_confirm);
2956 }
2957 EXPORT_SYMBOL(target_stop_session);
2958 
2959 /**
2960  * target_wait_for_sess_cmds - Wait for outstanding commands
2961  * @se_sess:    session to wait for active I/O
2962  */
2963 void target_wait_for_sess_cmds(struct se_session *se_sess)
2964 {
2965 	int ret;
2966 
2967 	WARN_ON_ONCE(!atomic_read(&se_sess->stopped));
2968 
2969 	do {
2970 		pr_debug("Waiting for running cmds to complete.\n");
2971 		ret = wait_event_timeout(se_sess->cmd_count_wq,
2972 				percpu_ref_is_zero(&se_sess->cmd_count),
2973 				180 * HZ);
2974 	} while (ret <= 0);
2975 
2976 	wait_for_completion(&se_sess->stop_done);
2977 	pr_debug("Waiting for cmds done.\n");
2978 }
2979 EXPORT_SYMBOL(target_wait_for_sess_cmds);
2980 
2981 /*
2982  * Prevent that new percpu_ref_tryget_live() calls succeed and wait until
2983  * all references to the LUN have been released. Called during LUN shutdown.
2984  */
2985 void transport_clear_lun_ref(struct se_lun *lun)
2986 {
2987 	percpu_ref_kill(&lun->lun_ref);
2988 	wait_for_completion(&lun->lun_shutdown_comp);
2989 }
2990 
2991 static bool
2992 __transport_wait_for_tasks(struct se_cmd *cmd, bool fabric_stop,
2993 			   bool *aborted, bool *tas, unsigned long *flags)
2994 	__releases(&cmd->t_state_lock)
2995 	__acquires(&cmd->t_state_lock)
2996 {
2997 
2998 	assert_spin_locked(&cmd->t_state_lock);
2999 	WARN_ON_ONCE(!irqs_disabled());
3000 
3001 	if (fabric_stop)
3002 		cmd->transport_state |= CMD_T_FABRIC_STOP;
3003 
3004 	if (cmd->transport_state & CMD_T_ABORTED)
3005 		*aborted = true;
3006 
3007 	if (cmd->transport_state & CMD_T_TAS)
3008 		*tas = true;
3009 
3010 	if (!(cmd->se_cmd_flags & SCF_SE_LUN_CMD) &&
3011 	    !(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
3012 		return false;
3013 
3014 	if (!(cmd->se_cmd_flags & SCF_SUPPORTED_SAM_OPCODE) &&
3015 	    !(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
3016 		return false;
3017 
3018 	if (!(cmd->transport_state & CMD_T_ACTIVE))
3019 		return false;
3020 
3021 	if (fabric_stop && *aborted)
3022 		return false;
3023 
3024 	cmd->transport_state |= CMD_T_STOP;
3025 
3026 	target_show_cmd("wait_for_tasks: Stopping ", cmd);
3027 
3028 	spin_unlock_irqrestore(&cmd->t_state_lock, *flags);
3029 
3030 	while (!wait_for_completion_timeout(&cmd->t_transport_stop_comp,
3031 					    180 * HZ))
3032 		target_show_cmd("wait for tasks: ", cmd);
3033 
3034 	spin_lock_irqsave(&cmd->t_state_lock, *flags);
3035 	cmd->transport_state &= ~(CMD_T_ACTIVE | CMD_T_STOP);
3036 
3037 	pr_debug("wait_for_tasks: Stopped wait_for_completion(&cmd->"
3038 		 "t_transport_stop_comp) for ITT: 0x%08llx\n", cmd->tag);
3039 
3040 	return true;
3041 }
3042 
3043 /**
3044  * transport_wait_for_tasks - set CMD_T_STOP and wait for t_transport_stop_comp
3045  * @cmd: command to wait on
3046  */
3047 bool transport_wait_for_tasks(struct se_cmd *cmd)
3048 {
3049 	unsigned long flags;
3050 	bool ret, aborted = false, tas = false;
3051 
3052 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3053 	ret = __transport_wait_for_tasks(cmd, false, &aborted, &tas, &flags);
3054 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3055 
3056 	return ret;
3057 }
3058 EXPORT_SYMBOL(transport_wait_for_tasks);
3059 
3060 struct sense_detail {
3061 	u8 key;
3062 	u8 asc;
3063 	u8 ascq;
3064 	bool add_sense_info;
3065 };
3066 
3067 static const struct sense_detail sense_detail_table[] = {
3068 	[TCM_NO_SENSE] = {
3069 		.key = NOT_READY
3070 	},
3071 	[TCM_NON_EXISTENT_LUN] = {
3072 		.key = ILLEGAL_REQUEST,
3073 		.asc = 0x25 /* LOGICAL UNIT NOT SUPPORTED */
3074 	},
3075 	[TCM_UNSUPPORTED_SCSI_OPCODE] = {
3076 		.key = ILLEGAL_REQUEST,
3077 		.asc = 0x20, /* INVALID COMMAND OPERATION CODE */
3078 	},
3079 	[TCM_SECTOR_COUNT_TOO_MANY] = {
3080 		.key = ILLEGAL_REQUEST,
3081 		.asc = 0x20, /* INVALID COMMAND OPERATION CODE */
3082 	},
3083 	[TCM_UNKNOWN_MODE_PAGE] = {
3084 		.key = ILLEGAL_REQUEST,
3085 		.asc = 0x24, /* INVALID FIELD IN CDB */
3086 	},
3087 	[TCM_CHECK_CONDITION_ABORT_CMD] = {
3088 		.key = ABORTED_COMMAND,
3089 		.asc = 0x29, /* BUS DEVICE RESET FUNCTION OCCURRED */
3090 		.ascq = 0x03,
3091 	},
3092 	[TCM_INCORRECT_AMOUNT_OF_DATA] = {
3093 		.key = ABORTED_COMMAND,
3094 		.asc = 0x0c, /* WRITE ERROR */
3095 		.ascq = 0x0d, /* NOT ENOUGH UNSOLICITED DATA */
3096 	},
3097 	[TCM_INVALID_CDB_FIELD] = {
3098 		.key = ILLEGAL_REQUEST,
3099 		.asc = 0x24, /* INVALID FIELD IN CDB */
3100 	},
3101 	[TCM_INVALID_PARAMETER_LIST] = {
3102 		.key = ILLEGAL_REQUEST,
3103 		.asc = 0x26, /* INVALID FIELD IN PARAMETER LIST */
3104 	},
3105 	[TCM_TOO_MANY_TARGET_DESCS] = {
3106 		.key = ILLEGAL_REQUEST,
3107 		.asc = 0x26,
3108 		.ascq = 0x06, /* TOO MANY TARGET DESCRIPTORS */
3109 	},
3110 	[TCM_UNSUPPORTED_TARGET_DESC_TYPE_CODE] = {
3111 		.key = ILLEGAL_REQUEST,
3112 		.asc = 0x26,
3113 		.ascq = 0x07, /* UNSUPPORTED TARGET DESCRIPTOR TYPE CODE */
3114 	},
3115 	[TCM_TOO_MANY_SEGMENT_DESCS] = {
3116 		.key = ILLEGAL_REQUEST,
3117 		.asc = 0x26,
3118 		.ascq = 0x08, /* TOO MANY SEGMENT DESCRIPTORS */
3119 	},
3120 	[TCM_UNSUPPORTED_SEGMENT_DESC_TYPE_CODE] = {
3121 		.key = ILLEGAL_REQUEST,
3122 		.asc = 0x26,
3123 		.ascq = 0x09, /* UNSUPPORTED SEGMENT DESCRIPTOR TYPE CODE */
3124 	},
3125 	[TCM_PARAMETER_LIST_LENGTH_ERROR] = {
3126 		.key = ILLEGAL_REQUEST,
3127 		.asc = 0x1a, /* PARAMETER LIST LENGTH ERROR */
3128 	},
3129 	[TCM_UNEXPECTED_UNSOLICITED_DATA] = {
3130 		.key = ILLEGAL_REQUEST,
3131 		.asc = 0x0c, /* WRITE ERROR */
3132 		.ascq = 0x0c, /* UNEXPECTED_UNSOLICITED_DATA */
3133 	},
3134 	[TCM_SERVICE_CRC_ERROR] = {
3135 		.key = ABORTED_COMMAND,
3136 		.asc = 0x47, /* PROTOCOL SERVICE CRC ERROR */
3137 		.ascq = 0x05, /* N/A */
3138 	},
3139 	[TCM_SNACK_REJECTED] = {
3140 		.key = ABORTED_COMMAND,
3141 		.asc = 0x11, /* READ ERROR */
3142 		.ascq = 0x13, /* FAILED RETRANSMISSION REQUEST */
3143 	},
3144 	[TCM_WRITE_PROTECTED] = {
3145 		.key = DATA_PROTECT,
3146 		.asc = 0x27, /* WRITE PROTECTED */
3147 	},
3148 	[TCM_ADDRESS_OUT_OF_RANGE] = {
3149 		.key = ILLEGAL_REQUEST,
3150 		.asc = 0x21, /* LOGICAL BLOCK ADDRESS OUT OF RANGE */
3151 	},
3152 	[TCM_CHECK_CONDITION_UNIT_ATTENTION] = {
3153 		.key = UNIT_ATTENTION,
3154 	},
3155 	[TCM_CHECK_CONDITION_NOT_READY] = {
3156 		.key = NOT_READY,
3157 	},
3158 	[TCM_MISCOMPARE_VERIFY] = {
3159 		.key = MISCOMPARE,
3160 		.asc = 0x1d, /* MISCOMPARE DURING VERIFY OPERATION */
3161 		.ascq = 0x00,
3162 		.add_sense_info = true,
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_sense_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_sense_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_sense_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_detail *sd;
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_detail_table) && sense_detail_table[r].key)
3235 		sd = &sense_detail_table[r];
3236 	else
3237 		sd = &sense_detail_table[(__force int)
3238 				       TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE];
3239 
3240 	key = sd->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 (sd->asc == 0) {
3248 		WARN_ON_ONCE(cmd->scsi_asc == 0);
3249 		asc = cmd->scsi_asc;
3250 		ascq = cmd->scsi_ascq;
3251 	} else {
3252 		asc = sd->asc;
3253 		ascq = sd->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 (sd->add_sense_info)
3261 		WARN_ON_ONCE(scsi_set_sense_information(buffer,
3262 							cmd->scsi_sense_length,
3263 							cmd->sense_info) < 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_lun_remove_cmd(cmd);
3354 	transport_cmd_check_stop_to_fabric(cmd);
3355 	return;
3356 
3357 aborted:
3358 	target_handle_abort(cmd);
3359 }
3360 
3361 int transport_generic_handle_tmr(
3362 	struct se_cmd *cmd)
3363 {
3364 	unsigned long flags;
3365 	bool aborted = false;
3366 
3367 	spin_lock_irqsave(&cmd->t_state_lock, flags);
3368 	if (cmd->transport_state & CMD_T_ABORTED) {
3369 		aborted = true;
3370 	} else {
3371 		cmd->t_state = TRANSPORT_ISTATE_PROCESSING;
3372 		cmd->transport_state |= CMD_T_ACTIVE;
3373 	}
3374 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
3375 
3376 	if (aborted) {
3377 		pr_warn_ratelimited("handle_tmr caught CMD_T_ABORTED TMR %d ref_tag: %llu tag: %llu\n",
3378 				    cmd->se_tmr_req->function,
3379 				    cmd->se_tmr_req->ref_task_tag, cmd->tag);
3380 		target_handle_abort(cmd);
3381 		return 0;
3382 	}
3383 
3384 	INIT_WORK(&cmd->work, target_tmr_work);
3385 	schedule_work(&cmd->work);
3386 	return 0;
3387 }
3388 EXPORT_SYMBOL(transport_generic_handle_tmr);
3389 
3390 bool
3391 target_check_wce(struct se_device *dev)
3392 {
3393 	bool wce = false;
3394 
3395 	if (dev->transport->get_write_cache)
3396 		wce = dev->transport->get_write_cache(dev);
3397 	else if (dev->dev_attrib.emulate_write_cache > 0)
3398 		wce = true;
3399 
3400 	return wce;
3401 }
3402 
3403 bool
3404 target_check_fua(struct se_device *dev)
3405 {
3406 	return target_check_wce(dev) && dev->dev_attrib.emulate_fua_write > 0;
3407 }
3408