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1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*******************************************************************************
3  * Filename:  target_core_tmr.c
4  *
5  * This file contains SPC-3 task management infrastructure
6  *
7  * (c) Copyright 2009-2013 Datera, Inc.
8  *
9  * Nicholas A. Bellinger <nab@kernel.org>
10  *
11  ******************************************************************************/
12 
13 #include <linux/slab.h>
14 #include <linux/spinlock.h>
15 #include <linux/list.h>
16 #include <linux/export.h>
17 
18 #include <target/target_core_base.h>
19 #include <target/target_core_backend.h>
20 #include <target/target_core_fabric.h>
21 
22 #include "target_core_internal.h"
23 #include "target_core_alua.h"
24 #include "target_core_pr.h"
25 
core_tmr_alloc_req(struct se_cmd * se_cmd,void * fabric_tmr_ptr,u8 function,gfp_t gfp_flags)26 int core_tmr_alloc_req(
27 	struct se_cmd *se_cmd,
28 	void *fabric_tmr_ptr,
29 	u8 function,
30 	gfp_t gfp_flags)
31 {
32 	struct se_tmr_req *tmr;
33 
34 	tmr = kzalloc(sizeof(struct se_tmr_req), gfp_flags);
35 	if (!tmr) {
36 		pr_err("Unable to allocate struct se_tmr_req\n");
37 		return -ENOMEM;
38 	}
39 
40 	se_cmd->se_cmd_flags |= SCF_SCSI_TMR_CDB;
41 	se_cmd->se_tmr_req = tmr;
42 	tmr->task_cmd = se_cmd;
43 	tmr->fabric_tmr_ptr = fabric_tmr_ptr;
44 	tmr->function = function;
45 	INIT_LIST_HEAD(&tmr->tmr_list);
46 
47 	return 0;
48 }
49 EXPORT_SYMBOL(core_tmr_alloc_req);
50 
core_tmr_release_req(struct se_tmr_req * tmr)51 void core_tmr_release_req(struct se_tmr_req *tmr)
52 {
53 	struct se_device *dev = tmr->tmr_dev;
54 	unsigned long flags;
55 
56 	if (dev) {
57 		spin_lock_irqsave(&dev->se_tmr_lock, flags);
58 		list_del_init(&tmr->tmr_list);
59 		spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
60 	}
61 
62 	kfree(tmr);
63 }
64 
target_check_cdb_and_preempt(struct list_head * list,struct se_cmd * cmd)65 static int target_check_cdb_and_preempt(struct list_head *list,
66 		struct se_cmd *cmd)
67 {
68 	struct t10_pr_registration *reg;
69 
70 	if (!list)
71 		return 0;
72 	list_for_each_entry(reg, list, pr_reg_abort_list) {
73 		if (reg->pr_res_key == cmd->pr_res_key)
74 			return 0;
75 	}
76 
77 	return 1;
78 }
79 
__target_check_io_state(struct se_cmd * se_cmd,struct se_session * tmr_sess,bool tas)80 static bool __target_check_io_state(struct se_cmd *se_cmd,
81 				    struct se_session *tmr_sess, bool tas)
82 {
83 	struct se_session *sess = se_cmd->se_sess;
84 
85 	assert_spin_locked(&sess->sess_cmd_lock);
86 	WARN_ON_ONCE(!irqs_disabled());
87 	/*
88 	 * If command already reached CMD_T_COMPLETE state within
89 	 * target_complete_cmd() or CMD_T_FABRIC_STOP due to shutdown,
90 	 * this se_cmd has been passed to fabric driver and will
91 	 * not be aborted.
92 	 *
93 	 * Otherwise, obtain a local se_cmd->cmd_kref now for TMR
94 	 * ABORT_TASK + LUN_RESET for CMD_T_ABORTED processing as
95 	 * long as se_cmd->cmd_kref is still active unless zero.
96 	 */
97 	spin_lock(&se_cmd->t_state_lock);
98 	if (se_cmd->transport_state & (CMD_T_COMPLETE | CMD_T_FABRIC_STOP)) {
99 		pr_debug("Attempted to abort io tag: %llu already complete or"
100 			" fabric stop, skipping\n", se_cmd->tag);
101 		spin_unlock(&se_cmd->t_state_lock);
102 		return false;
103 	}
104 	se_cmd->transport_state |= CMD_T_ABORTED;
105 
106 	if ((tmr_sess != se_cmd->se_sess) && tas)
107 		se_cmd->transport_state |= CMD_T_TAS;
108 
109 	spin_unlock(&se_cmd->t_state_lock);
110 
111 	return kref_get_unless_zero(&se_cmd->cmd_kref);
112 }
113 
core_tmr_abort_task(struct se_device * dev,struct se_tmr_req * tmr,struct se_session * se_sess)114 void core_tmr_abort_task(
115 	struct se_device *dev,
116 	struct se_tmr_req *tmr,
117 	struct se_session *se_sess)
118 {
119 	LIST_HEAD(aborted_list);
120 	struct se_cmd *se_cmd, *next;
121 	unsigned long flags;
122 	bool rc;
123 	u64 ref_tag;
124 
125 	spin_lock_irqsave(&dev->execute_task_lock, flags);
126 	list_for_each_entry_safe(se_cmd, next, &dev->state_list, state_list) {
127 
128 		if (se_sess != se_cmd->se_sess)
129 			continue;
130 
131 		/* skip task management functions, including tmr->task_cmd */
132 		if (se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
133 			continue;
134 
135 		ref_tag = se_cmd->tag;
136 		if (tmr->ref_task_tag != ref_tag)
137 			continue;
138 
139 		printk("ABORT_TASK: Found referenced %s task_tag: %llu\n",
140 			se_cmd->se_tfo->fabric_name, ref_tag);
141 
142 		spin_lock(&se_sess->sess_cmd_lock);
143 		rc = __target_check_io_state(se_cmd, se_sess, 0);
144 		spin_unlock(&se_sess->sess_cmd_lock);
145 		if (!rc)
146 			continue;
147 
148 		list_move_tail(&se_cmd->state_list, &aborted_list);
149 		se_cmd->state_active = false;
150 
151 		spin_unlock_irqrestore(&dev->execute_task_lock, flags);
152 
153 		/*
154 		 * Ensure that this ABORT request is visible to the LU RESET
155 		 * code.
156 		 */
157 		if (!tmr->tmr_dev)
158 			WARN_ON_ONCE(transport_lookup_tmr_lun(tmr->task_cmd) <
159 					0);
160 
161 		if (dev->transport->tmr_notify)
162 			dev->transport->tmr_notify(dev, TMR_ABORT_TASK,
163 						   &aborted_list);
164 
165 		list_del_init(&se_cmd->state_list);
166 		target_put_cmd_and_wait(se_cmd);
167 
168 		printk("ABORT_TASK: Sending TMR_FUNCTION_COMPLETE for"
169 				" ref_tag: %llu\n", ref_tag);
170 		tmr->response = TMR_FUNCTION_COMPLETE;
171 		atomic_long_inc(&dev->aborts_complete);
172 		return;
173 	}
174 	spin_unlock_irqrestore(&dev->execute_task_lock, flags);
175 
176 	if (dev->transport->tmr_notify)
177 		dev->transport->tmr_notify(dev, TMR_ABORT_TASK, &aborted_list);
178 
179 	printk("ABORT_TASK: Sending TMR_TASK_DOES_NOT_EXIST for ref_tag: %lld\n",
180 			tmr->ref_task_tag);
181 	tmr->response = TMR_TASK_DOES_NOT_EXIST;
182 	atomic_long_inc(&dev->aborts_no_task);
183 }
184 
core_tmr_drain_tmr_list(struct se_device * dev,struct se_tmr_req * tmr,struct list_head * preempt_and_abort_list)185 static void core_tmr_drain_tmr_list(
186 	struct se_device *dev,
187 	struct se_tmr_req *tmr,
188 	struct list_head *preempt_and_abort_list)
189 {
190 	LIST_HEAD(drain_tmr_list);
191 	struct se_session *sess;
192 	struct se_tmr_req *tmr_p, *tmr_pp;
193 	struct se_cmd *cmd;
194 	unsigned long flags;
195 	bool rc;
196 	/*
197 	 * Release all pending and outgoing TMRs aside from the received
198 	 * LUN_RESET tmr..
199 	 */
200 	spin_lock_irqsave(&dev->se_tmr_lock, flags);
201 	if (tmr)
202 		list_del_init(&tmr->tmr_list);
203 	list_for_each_entry_safe(tmr_p, tmr_pp, &dev->dev_tmr_list, tmr_list) {
204 		cmd = tmr_p->task_cmd;
205 		if (!cmd) {
206 			pr_err("Unable to locate struct se_cmd for TMR\n");
207 			continue;
208 		}
209 		/*
210 		 * If this function was called with a valid pr_res_key
211 		 * parameter (eg: for PROUT PREEMPT_AND_ABORT service action
212 		 * skip non registration key matching TMRs.
213 		 */
214 		if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
215 			continue;
216 
217 		sess = cmd->se_sess;
218 		if (WARN_ON_ONCE(!sess))
219 			continue;
220 
221 		spin_lock(&sess->sess_cmd_lock);
222 		rc = __target_check_io_state(cmd, sess, 0);
223 		spin_unlock(&sess->sess_cmd_lock);
224 
225 		if (!rc) {
226 			printk("LUN_RESET TMR: non-zero kref_get_unless_zero\n");
227 			continue;
228 		}
229 
230 		list_move_tail(&tmr_p->tmr_list, &drain_tmr_list);
231 	}
232 	spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
233 
234 	list_for_each_entry_safe(tmr_p, tmr_pp, &drain_tmr_list, tmr_list) {
235 		list_del_init(&tmr_p->tmr_list);
236 		cmd = tmr_p->task_cmd;
237 
238 		pr_debug("LUN_RESET: %s releasing TMR %p Function: 0x%02x,"
239 			" Response: 0x%02x, t_state: %d\n",
240 			(preempt_and_abort_list) ? "Preempt" : "", tmr_p,
241 			tmr_p->function, tmr_p->response, cmd->t_state);
242 
243 		target_put_cmd_and_wait(cmd);
244 	}
245 }
246 
247 /**
248  * core_tmr_drain_state_list() - abort SCSI commands associated with a device
249  *
250  * @dev:       Device for which to abort outstanding SCSI commands.
251  * @prout_cmd: Pointer to the SCSI PREEMPT AND ABORT if this function is called
252  *             to realize the PREEMPT AND ABORT functionality.
253  * @tmr_sess:  Session through which the LUN RESET has been received.
254  * @tas:       Task Aborted Status (TAS) bit from the SCSI control mode page.
255  *             A quote from SPC-4, paragraph "7.5.10 Control mode page":
256  *             "A task aborted status (TAS) bit set to zero specifies that
257  *             aborted commands shall be terminated by the device server
258  *             without any response to the application client. A TAS bit set
259  *             to one specifies that commands aborted by the actions of an I_T
260  *             nexus other than the I_T nexus on which the command was
261  *             received shall be completed with TASK ABORTED status."
262  * @preempt_and_abort_list: For the PREEMPT AND ABORT functionality, a list
263  *             with registrations that will be preempted.
264  */
core_tmr_drain_state_list(struct se_device * dev,struct se_cmd * prout_cmd,struct se_session * tmr_sess,bool tas,struct list_head * preempt_and_abort_list)265 static void core_tmr_drain_state_list(
266 	struct se_device *dev,
267 	struct se_cmd *prout_cmd,
268 	struct se_session *tmr_sess,
269 	bool tas,
270 	struct list_head *preempt_and_abort_list)
271 {
272 	LIST_HEAD(drain_task_list);
273 	struct se_session *sess;
274 	struct se_cmd *cmd, *next;
275 	unsigned long flags;
276 	int rc;
277 
278 	/*
279 	 * Complete outstanding commands with TASK_ABORTED SAM status.
280 	 *
281 	 * This is following sam4r17, section 5.6 Aborting commands, Table 38
282 	 * for TMR LUN_RESET:
283 	 *
284 	 * a) "Yes" indicates that each command that is aborted on an I_T nexus
285 	 * other than the one that caused the SCSI device condition is
286 	 * completed with TASK ABORTED status, if the TAS bit is set to one in
287 	 * the Control mode page (see SPC-4). "No" indicates that no status is
288 	 * returned for aborted commands.
289 	 *
290 	 * d) If the logical unit reset is caused by a particular I_T nexus
291 	 * (e.g., by a LOGICAL UNIT RESET task management function), then "yes"
292 	 * (TASK_ABORTED status) applies.
293 	 *
294 	 * Otherwise (e.g., if triggered by a hard reset), "no"
295 	 * (no TASK_ABORTED SAM status) applies.
296 	 *
297 	 * Note that this seems to be independent of TAS (Task Aborted Status)
298 	 * in the Control Mode Page.
299 	 */
300 	spin_lock_irqsave(&dev->execute_task_lock, flags);
301 	list_for_each_entry_safe(cmd, next, &dev->state_list, state_list) {
302 		/*
303 		 * For PREEMPT_AND_ABORT usage, only process commands
304 		 * with a matching reservation key.
305 		 */
306 		if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
307 			continue;
308 
309 		/*
310 		 * Not aborting PROUT PREEMPT_AND_ABORT CDB..
311 		 */
312 		if (prout_cmd == cmd)
313 			continue;
314 
315 		sess = cmd->se_sess;
316 		if (WARN_ON_ONCE(!sess))
317 			continue;
318 
319 		spin_lock(&sess->sess_cmd_lock);
320 		rc = __target_check_io_state(cmd, tmr_sess, tas);
321 		spin_unlock(&sess->sess_cmd_lock);
322 		if (!rc)
323 			continue;
324 
325 		list_move_tail(&cmd->state_list, &drain_task_list);
326 		cmd->state_active = false;
327 	}
328 	spin_unlock_irqrestore(&dev->execute_task_lock, flags);
329 
330 	if (dev->transport->tmr_notify)
331 		dev->transport->tmr_notify(dev, preempt_and_abort_list ?
332 					   TMR_LUN_RESET_PRO : TMR_LUN_RESET,
333 					   &drain_task_list);
334 
335 	while (!list_empty(&drain_task_list)) {
336 		cmd = list_entry(drain_task_list.next, struct se_cmd, state_list);
337 		list_del_init(&cmd->state_list);
338 
339 		target_show_cmd("LUN_RESET: ", cmd);
340 		pr_debug("LUN_RESET: ITT[0x%08llx] - %s pr_res_key: 0x%016Lx\n",
341 			 cmd->tag, (preempt_and_abort_list) ? "preempt" : "",
342 			 cmd->pr_res_key);
343 
344 		target_put_cmd_and_wait(cmd);
345 	}
346 }
347 
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)348 int core_tmr_lun_reset(
349         struct se_device *dev,
350         struct se_tmr_req *tmr,
351         struct list_head *preempt_and_abort_list,
352         struct se_cmd *prout_cmd)
353 {
354 	struct se_node_acl *tmr_nacl = NULL;
355 	struct se_portal_group *tmr_tpg = NULL;
356 	struct se_session *tmr_sess = NULL;
357 	bool tas;
358         /*
359 	 * TASK_ABORTED status bit, this is configurable via ConfigFS
360 	 * struct se_device attributes.  spc4r17 section 7.4.6 Control mode page
361 	 *
362 	 * A task aborted status (TAS) bit set to zero specifies that aborted
363 	 * tasks shall be terminated by the device server without any response
364 	 * to the application client. A TAS bit set to one specifies that tasks
365 	 * aborted by the actions of an I_T nexus other than the I_T nexus on
366 	 * which the command was received shall be completed with TASK ABORTED
367 	 * status (see SAM-4).
368 	 */
369 	tas = dev->dev_attrib.emulate_tas;
370 	/*
371 	 * Determine if this se_tmr is coming from a $FABRIC_MOD
372 	 * or struct se_device passthrough..
373 	 */
374 	if (tmr && tmr->task_cmd && tmr->task_cmd->se_sess) {
375 		tmr_sess = tmr->task_cmd->se_sess;
376 		tmr_nacl = tmr_sess->se_node_acl;
377 		tmr_tpg = tmr_sess->se_tpg;
378 		if (tmr_nacl && tmr_tpg) {
379 			pr_debug("LUN_RESET: TMR caller fabric: %s"
380 				" initiator port %s\n",
381 				tmr_tpg->se_tpg_tfo->fabric_name,
382 				tmr_nacl->initiatorname);
383 		}
384 	}
385 	pr_debug("LUN_RESET: %s starting for [%s], tas: %d\n",
386 		(preempt_and_abort_list) ? "Preempt" : "TMR",
387 		dev->transport->name, tas);
388 
389 	core_tmr_drain_tmr_list(dev, tmr, preempt_and_abort_list);
390 	core_tmr_drain_state_list(dev, prout_cmd, tmr_sess, tas,
391 				preempt_and_abort_list);
392 
393 	/*
394 	 * Clear any legacy SPC-2 reservation when called during
395 	 * LOGICAL UNIT RESET
396 	 */
397 	if (!preempt_and_abort_list &&
398 	     (dev->dev_reservation_flags & DRF_SPC2_RESERVATIONS)) {
399 		spin_lock(&dev->dev_reservation_lock);
400 		dev->reservation_holder = NULL;
401 		dev->dev_reservation_flags &= ~DRF_SPC2_RESERVATIONS;
402 		spin_unlock(&dev->dev_reservation_lock);
403 		pr_debug("LUN_RESET: SCSI-2 Released reservation\n");
404 	}
405 
406 	atomic_long_inc(&dev->num_resets);
407 
408 	pr_debug("LUN_RESET: %s for [%s] Complete\n",
409 			(preempt_and_abort_list) ? "Preempt" : "TMR",
410 			dev->transport->name);
411 	return 0;
412 }
413 
414