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1 /*******************************************************************************
2  * Filename:  target_core_tmr.c
3  *
4  * This file contains SPC-3 task management infrastructure
5  *
6  * (c) Copyright 2009-2013 Datera, Inc.
7  *
8  * Nicholas A. Bellinger <nab@kernel.org>
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License as published by
12  * the Free Software Foundation; either version 2 of the License, or
13  * (at your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18  * GNU General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with this program; if not, write to the Free Software
22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
23  *
24  ******************************************************************************/
25 
26 #include <linux/slab.h>
27 #include <linux/spinlock.h>
28 #include <linux/list.h>
29 #include <linux/export.h>
30 #include <scsi/scsi.h>
31 #include <scsi/scsi_cmnd.h>
32 
33 #include <target/target_core_base.h>
34 #include <target/target_core_backend.h>
35 #include <target/target_core_fabric.h>
36 #include <target/target_core_configfs.h>
37 
38 #include "target_core_internal.h"
39 #include "target_core_alua.h"
40 #include "target_core_pr.h"
41 
core_tmr_alloc_req(struct se_cmd * se_cmd,void * fabric_tmr_ptr,u8 function,gfp_t gfp_flags)42 int core_tmr_alloc_req(
43 	struct se_cmd *se_cmd,
44 	void *fabric_tmr_ptr,
45 	u8 function,
46 	gfp_t gfp_flags)
47 {
48 	struct se_tmr_req *tmr;
49 
50 	tmr = kzalloc(sizeof(struct se_tmr_req), gfp_flags);
51 	if (!tmr) {
52 		pr_err("Unable to allocate struct se_tmr_req\n");
53 		return -ENOMEM;
54 	}
55 
56 	se_cmd->se_cmd_flags |= SCF_SCSI_TMR_CDB;
57 	se_cmd->se_tmr_req = tmr;
58 	tmr->task_cmd = se_cmd;
59 	tmr->fabric_tmr_ptr = fabric_tmr_ptr;
60 	tmr->function = function;
61 	INIT_LIST_HEAD(&tmr->tmr_list);
62 
63 	return 0;
64 }
65 EXPORT_SYMBOL(core_tmr_alloc_req);
66 
core_tmr_release_req(struct se_tmr_req * tmr)67 void core_tmr_release_req(struct se_tmr_req *tmr)
68 {
69 	struct se_device *dev = tmr->tmr_dev;
70 	unsigned long flags;
71 
72 	if (dev) {
73 		spin_lock_irqsave(&dev->se_tmr_lock, flags);
74 		list_del_init(&tmr->tmr_list);
75 		spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
76 	}
77 
78 	kfree(tmr);
79 }
80 
core_tmr_handle_tas_abort(struct se_cmd * cmd,int tas)81 static int core_tmr_handle_tas_abort(struct se_cmd *cmd, int tas)
82 {
83 	unsigned long flags;
84 	bool remove = true, send_tas;
85 	/*
86 	 * TASK ABORTED status (TAS) bit support
87 	 */
88 	spin_lock_irqsave(&cmd->t_state_lock, flags);
89 	send_tas = (cmd->transport_state & CMD_T_TAS);
90 	spin_unlock_irqrestore(&cmd->t_state_lock, flags);
91 
92 	if (send_tas) {
93 		remove = false;
94 		transport_send_task_abort(cmd);
95 	}
96 
97 	return transport_cmd_finish_abort(cmd, remove);
98 }
99 
target_check_cdb_and_preempt(struct list_head * list,struct se_cmd * cmd)100 static int target_check_cdb_and_preempt(struct list_head *list,
101 		struct se_cmd *cmd)
102 {
103 	struct t10_pr_registration *reg;
104 
105 	if (!list)
106 		return 0;
107 	list_for_each_entry(reg, list, pr_reg_abort_list) {
108 		if (reg->pr_res_key == cmd->pr_res_key)
109 			return 0;
110 	}
111 
112 	return 1;
113 }
114 
__target_check_io_state(struct se_cmd * se_cmd,struct se_session * tmr_sess,int tas)115 static bool __target_check_io_state(struct se_cmd *se_cmd,
116 				    struct se_session *tmr_sess, int tas)
117 {
118 	struct se_session *sess = se_cmd->se_sess;
119 
120 	assert_spin_locked(&sess->sess_cmd_lock);
121 	WARN_ON_ONCE(!irqs_disabled());
122 	/*
123 	 * If command already reached CMD_T_COMPLETE state within
124 	 * target_complete_cmd() or CMD_T_FABRIC_STOP due to shutdown,
125 	 * this se_cmd has been passed to fabric driver and will
126 	 * not be aborted.
127 	 *
128 	 * Otherwise, obtain a local se_cmd->cmd_kref now for TMR
129 	 * ABORT_TASK + LUN_RESET for CMD_T_ABORTED processing as
130 	 * long as se_cmd->cmd_kref is still active unless zero.
131 	 */
132 	spin_lock(&se_cmd->t_state_lock);
133 	if (se_cmd->transport_state & (CMD_T_COMPLETE | CMD_T_FABRIC_STOP)) {
134 		pr_debug("Attempted to abort io tag: %u already complete or"
135 			" fabric stop, skipping\n",
136 			se_cmd->se_tfo->get_task_tag(se_cmd));
137 		spin_unlock(&se_cmd->t_state_lock);
138 		return false;
139 	}
140 	if (se_cmd->transport_state & CMD_T_PRE_EXECUTE) {
141 		if (se_cmd->scsi_status) {
142 			pr_debug("Attempted to abort io tag: %u early failure"
143 				 " status: 0x%02x\n", se_cmd->se_tfo->get_task_tag(se_cmd),
144 				 se_cmd->scsi_status);
145 			spin_unlock(&se_cmd->t_state_lock);
146 			return false;
147 		}
148 	}
149 	if (sess->sess_tearing_down || se_cmd->cmd_wait_set) {
150 		pr_debug("Attempted to abort io tag: %u already shutdown,"
151 			" skipping\n", se_cmd->se_tfo->get_task_tag(se_cmd));
152 		spin_unlock(&se_cmd->t_state_lock);
153 		return false;
154 	}
155 	se_cmd->transport_state |= CMD_T_ABORTED;
156 
157 	if ((tmr_sess != se_cmd->se_sess) && tas)
158 		se_cmd->transport_state |= CMD_T_TAS;
159 
160 	spin_unlock(&se_cmd->t_state_lock);
161 
162 	return kref_get_unless_zero(&se_cmd->cmd_kref);
163 }
164 
core_tmr_abort_task(struct se_device * dev,struct se_tmr_req * tmr,struct se_session * se_sess)165 void core_tmr_abort_task(
166 	struct se_device *dev,
167 	struct se_tmr_req *tmr,
168 	struct se_session *se_sess)
169 {
170 	struct se_cmd *se_cmd;
171 	unsigned long flags;
172 	int ref_tag;
173 
174 	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
175 	list_for_each_entry(se_cmd, &se_sess->sess_cmd_list, se_cmd_list) {
176 
177 		if (dev != se_cmd->se_dev)
178 			continue;
179 
180 		/* skip se_cmd associated with tmr */
181 		if (tmr->task_cmd == se_cmd)
182 			continue;
183 
184 		ref_tag = se_cmd->se_tfo->get_task_tag(se_cmd);
185 		if (tmr->ref_task_tag != ref_tag)
186 			continue;
187 
188 		printk("ABORT_TASK: Found referenced %s task_tag: %u\n",
189 			se_cmd->se_tfo->get_fabric_name(), ref_tag);
190 
191 		if (!__target_check_io_state(se_cmd, se_sess, 0)) {
192 			spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
193 			goto out;
194 		}
195 
196 		list_del_init(&se_cmd->se_cmd_list);
197 		spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
198 
199 		cancel_work_sync(&se_cmd->work);
200 		transport_wait_for_tasks(se_cmd);
201 
202 		if (!transport_cmd_finish_abort(se_cmd, true))
203 			target_put_sess_cmd(se_cmd);
204 
205 		printk("ABORT_TASK: Sending TMR_FUNCTION_COMPLETE for"
206 				" ref_tag: %d\n", ref_tag);
207 		tmr->response = TMR_FUNCTION_COMPLETE;
208 		return;
209 	}
210 	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
211 
212 out:
213 	printk("ABORT_TASK: Sending TMR_TASK_DOES_NOT_EXIST for ref_tag: %d\n",
214 			tmr->ref_task_tag);
215 	tmr->response = TMR_TASK_DOES_NOT_EXIST;
216 }
217 
core_tmr_drain_tmr_list(struct se_device * dev,struct se_tmr_req * tmr,struct list_head * preempt_and_abort_list)218 static void core_tmr_drain_tmr_list(
219 	struct se_device *dev,
220 	struct se_tmr_req *tmr,
221 	struct list_head *preempt_and_abort_list)
222 {
223 	LIST_HEAD(drain_tmr_list);
224 	struct se_session *sess;
225 	struct se_tmr_req *tmr_p, *tmr_pp;
226 	struct se_cmd *cmd;
227 	unsigned long flags;
228 	bool rc;
229 	/*
230 	 * Release all pending and outgoing TMRs aside from the received
231 	 * LUN_RESET tmr..
232 	 */
233 	spin_lock_irqsave(&dev->se_tmr_lock, flags);
234 	list_for_each_entry_safe(tmr_p, tmr_pp, &dev->dev_tmr_list, tmr_list) {
235 		/*
236 		 * Allow the received TMR to return with FUNCTION_COMPLETE.
237 		 */
238 		if (tmr_p == tmr)
239 			continue;
240 
241 		cmd = tmr_p->task_cmd;
242 		if (!cmd) {
243 			pr_err("Unable to locate struct se_cmd for TMR\n");
244 			continue;
245 		}
246 		/*
247 		 * If this function was called with a valid pr_res_key
248 		 * parameter (eg: for PROUT PREEMPT_AND_ABORT service action
249 		 * skip non regisration key matching TMRs.
250 		 */
251 		if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
252 			continue;
253 
254 		sess = cmd->se_sess;
255 		if (WARN_ON_ONCE(!sess))
256 			continue;
257 
258 		spin_lock(&sess->sess_cmd_lock);
259 		spin_lock(&cmd->t_state_lock);
260 		if (!(cmd->transport_state & CMD_T_ACTIVE) ||
261 		     (cmd->transport_state & CMD_T_FABRIC_STOP)) {
262 			spin_unlock(&cmd->t_state_lock);
263 			spin_unlock(&sess->sess_cmd_lock);
264 			continue;
265 		}
266 		if (cmd->t_state == TRANSPORT_ISTATE_PROCESSING) {
267 			spin_unlock(&cmd->t_state_lock);
268 			spin_unlock(&sess->sess_cmd_lock);
269 			continue;
270 		}
271 		if (sess->sess_tearing_down || cmd->cmd_wait_set) {
272 			spin_unlock(&cmd->t_state_lock);
273 			spin_unlock(&sess->sess_cmd_lock);
274 			continue;
275 		}
276 		cmd->transport_state |= CMD_T_ABORTED;
277 		spin_unlock(&cmd->t_state_lock);
278 
279 		rc = kref_get_unless_zero(&cmd->cmd_kref);
280 		if (!rc) {
281 			printk("LUN_RESET TMR: non-zero kref_get_unless_zero\n");
282 			spin_unlock(&sess->sess_cmd_lock);
283 			continue;
284 		}
285 		spin_unlock(&sess->sess_cmd_lock);
286 
287 		list_move_tail(&tmr_p->tmr_list, &drain_tmr_list);
288 	}
289 	spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
290 
291 	list_for_each_entry_safe(tmr_p, tmr_pp, &drain_tmr_list, tmr_list) {
292 		list_del_init(&tmr_p->tmr_list);
293 		cmd = tmr_p->task_cmd;
294 
295 		pr_debug("LUN_RESET: %s releasing TMR %p Function: 0x%02x,"
296 			" Response: 0x%02x, t_state: %d\n",
297 			(preempt_and_abort_list) ? "Preempt" : "", tmr_p,
298 			tmr_p->function, tmr_p->response, cmd->t_state);
299 
300 		cancel_work_sync(&cmd->work);
301 		transport_wait_for_tasks(cmd);
302 
303 		if (!transport_cmd_finish_abort(cmd, 1))
304 			target_put_sess_cmd(cmd);
305 	}
306 }
307 
core_tmr_drain_state_list(struct se_device * dev,struct se_cmd * prout_cmd,struct se_session * tmr_sess,int tas,struct list_head * preempt_and_abort_list)308 static void core_tmr_drain_state_list(
309 	struct se_device *dev,
310 	struct se_cmd *prout_cmd,
311 	struct se_session *tmr_sess,
312 	int tas,
313 	struct list_head *preempt_and_abort_list)
314 {
315 	LIST_HEAD(drain_task_list);
316 	struct se_session *sess;
317 	struct se_cmd *cmd, *next;
318 	unsigned long flags;
319 	int rc;
320 
321 	/*
322 	 * Complete outstanding commands with TASK_ABORTED SAM status.
323 	 *
324 	 * This is following sam4r17, section 5.6 Aborting commands, Table 38
325 	 * for TMR LUN_RESET:
326 	 *
327 	 * a) "Yes" indicates that each command that is aborted on an I_T nexus
328 	 * other than the one that caused the SCSI device condition is
329 	 * completed with TASK ABORTED status, if the TAS bit is set to one in
330 	 * the Control mode page (see SPC-4). "No" indicates that no status is
331 	 * returned for aborted commands.
332 	 *
333 	 * d) If the logical unit reset is caused by a particular I_T nexus
334 	 * (e.g., by a LOGICAL UNIT RESET task management function), then "yes"
335 	 * (TASK_ABORTED status) applies.
336 	 *
337 	 * Otherwise (e.g., if triggered by a hard reset), "no"
338 	 * (no TASK_ABORTED SAM status) applies.
339 	 *
340 	 * Note that this seems to be independent of TAS (Task Aborted Status)
341 	 * in the Control Mode Page.
342 	 */
343 	spin_lock_irqsave(&dev->execute_task_lock, flags);
344 	list_for_each_entry_safe(cmd, next, &dev->state_list, state_list) {
345 		/*
346 		 * For PREEMPT_AND_ABORT usage, only process commands
347 		 * with a matching reservation key.
348 		 */
349 		if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
350 			continue;
351 
352 		/*
353 		 * Not aborting PROUT PREEMPT_AND_ABORT CDB..
354 		 */
355 		if (prout_cmd == cmd)
356 			continue;
357 
358 		sess = cmd->se_sess;
359 		if (WARN_ON_ONCE(!sess))
360 			continue;
361 
362 		spin_lock(&sess->sess_cmd_lock);
363 		rc = __target_check_io_state(cmd, tmr_sess, tas);
364 		spin_unlock(&sess->sess_cmd_lock);
365 		if (!rc)
366 			continue;
367 
368 		list_move_tail(&cmd->state_list, &drain_task_list);
369 		cmd->state_active = false;
370 	}
371 	spin_unlock_irqrestore(&dev->execute_task_lock, flags);
372 
373 	while (!list_empty(&drain_task_list)) {
374 		cmd = list_entry(drain_task_list.next, struct se_cmd, state_list);
375 		list_del_init(&cmd->state_list);
376 
377 		pr_debug("LUN_RESET: %s cmd: %p"
378 			" ITT/CmdSN: 0x%08x/0x%08x, i_state: %d, t_state: %d"
379 			"cdb: 0x%02x\n",
380 			(preempt_and_abort_list) ? "Preempt" : "", cmd,
381 			cmd->se_tfo->get_task_tag(cmd), 0,
382 			cmd->se_tfo->get_cmd_state(cmd), cmd->t_state,
383 			cmd->t_task_cdb[0]);
384 		pr_debug("LUN_RESET: ITT[0x%08x] - pr_res_key: 0x%016Lx"
385 			" -- CMD_T_ACTIVE: %d"
386 			" CMD_T_STOP: %d CMD_T_SENT: %d\n",
387 			cmd->se_tfo->get_task_tag(cmd), cmd->pr_res_key,
388 			(cmd->transport_state & CMD_T_ACTIVE) != 0,
389 			(cmd->transport_state & CMD_T_STOP) != 0,
390 			(cmd->transport_state & CMD_T_SENT) != 0);
391 
392 		/*
393 		 * If the command may be queued onto a workqueue cancel it now.
394 		 *
395 		 * This is equivalent to removal from the execute queue in the
396 		 * loop above, but we do it down here given that
397 		 * cancel_work_sync may block.
398 		 */
399 		cancel_work_sync(&cmd->work);
400 		transport_wait_for_tasks(cmd);
401 
402 		if (!core_tmr_handle_tas_abort(cmd, tas))
403 			target_put_sess_cmd(cmd);
404 	}
405 }
406 
core_tmr_lun_reset(struct se_device * dev,struct se_tmr_req * tmr,struct list_head * preempt_and_abort_list,struct se_cmd * prout_cmd)407 int core_tmr_lun_reset(
408         struct se_device *dev,
409         struct se_tmr_req *tmr,
410         struct list_head *preempt_and_abort_list,
411         struct se_cmd *prout_cmd)
412 {
413 	struct se_node_acl *tmr_nacl = NULL;
414 	struct se_portal_group *tmr_tpg = NULL;
415 	struct se_session *tmr_sess = NULL;
416 	int tas;
417         /*
418 	 * TASK_ABORTED status bit, this is configurable via ConfigFS
419 	 * struct se_device attributes.  spc4r17 section 7.4.6 Control mode page
420 	 *
421 	 * A task aborted status (TAS) bit set to zero specifies that aborted
422 	 * tasks shall be terminated by the device server without any response
423 	 * to the application client. A TAS bit set to one specifies that tasks
424 	 * aborted by the actions of an I_T nexus other than the I_T nexus on
425 	 * which the command was received shall be completed with TASK ABORTED
426 	 * status (see SAM-4).
427 	 */
428 	tas = dev->dev_attrib.emulate_tas;
429 	/*
430 	 * Determine if this se_tmr is coming from a $FABRIC_MOD
431 	 * or struct se_device passthrough..
432 	 */
433 	if (tmr && tmr->task_cmd && tmr->task_cmd->se_sess) {
434 		tmr_sess = tmr->task_cmd->se_sess;
435 		tmr_nacl = tmr_sess->se_node_acl;
436 		tmr_tpg = tmr_sess->se_tpg;
437 		if (tmr_nacl && tmr_tpg) {
438 			pr_debug("LUN_RESET: TMR caller fabric: %s"
439 				" initiator port %s\n",
440 				tmr_tpg->se_tpg_tfo->get_fabric_name(),
441 				tmr_nacl->initiatorname);
442 		}
443 	}
444 	pr_debug("LUN_RESET: %s starting for [%s], tas: %d\n",
445 		(preempt_and_abort_list) ? "Preempt" : "TMR",
446 		dev->transport->name, tas);
447 
448 	core_tmr_drain_tmr_list(dev, tmr, preempt_and_abort_list);
449 	core_tmr_drain_state_list(dev, prout_cmd, tmr_sess, tas,
450 				preempt_and_abort_list);
451 
452 	/*
453 	 * Clear any legacy SPC-2 reservation when called during
454 	 * LOGICAL UNIT RESET
455 	 */
456 	if (!preempt_and_abort_list &&
457 	     (dev->dev_reservation_flags & DRF_SPC2_RESERVATIONS)) {
458 		spin_lock(&dev->dev_reservation_lock);
459 		dev->dev_reserved_node_acl = NULL;
460 		dev->dev_reservation_flags &= ~DRF_SPC2_RESERVATIONS;
461 		spin_unlock(&dev->dev_reservation_lock);
462 		pr_debug("LUN_RESET: SCSI-2 Released reservation\n");
463 	}
464 
465 	atomic_long_inc(&dev->num_resets);
466 
467 	pr_debug("LUN_RESET: %s for [%s] Complete\n",
468 			(preempt_and_abort_list) ? "Preempt" : "TMR",
469 			dev->transport->name);
470 	return 0;
471 }
472 
473