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