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 lockdep_assert_held(&sess->sess_cmd_lock);
86
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 int i;
125
126 for (i = 0; i < dev->queue_cnt; i++) {
127 spin_lock_irqsave(&dev->queues[i].lock, flags);
128 list_for_each_entry_safe(se_cmd, next, &dev->queues[i].state_list,
129 state_list) {
130 if (se_sess != se_cmd->se_sess)
131 continue;
132
133 /*
134 * skip task management functions, including
135 * tmr->task_cmd
136 */
137 if (se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
138 continue;
139
140 ref_tag = se_cmd->tag;
141 if (tmr->ref_task_tag != ref_tag)
142 continue;
143
144 pr_err("ABORT_TASK: Found referenced %s task_tag: %llu\n",
145 se_cmd->se_tfo->fabric_name, ref_tag);
146
147 spin_lock(&se_sess->sess_cmd_lock);
148 rc = __target_check_io_state(se_cmd, se_sess, 0);
149 spin_unlock(&se_sess->sess_cmd_lock);
150 if (!rc)
151 continue;
152
153 list_move_tail(&se_cmd->state_list, &aborted_list);
154 se_cmd->state_active = false;
155 spin_unlock_irqrestore(&dev->queues[i].lock, flags);
156
157 /*
158 * Ensure that this ABORT request is visible to the LU
159 * RESET code.
160 */
161 if (!tmr->tmr_dev)
162 WARN_ON_ONCE(transport_lookup_tmr_lun(tmr->task_cmd) < 0);
163
164 if (dev->transport->tmr_notify)
165 dev->transport->tmr_notify(dev, TMR_ABORT_TASK,
166 &aborted_list);
167
168 list_del_init(&se_cmd->state_list);
169 target_put_cmd_and_wait(se_cmd);
170
171 pr_err("ABORT_TASK: Sending TMR_FUNCTION_COMPLETE for ref_tag: %llu\n",
172 ref_tag);
173 tmr->response = TMR_FUNCTION_COMPLETE;
174 atomic_long_inc(&dev->aborts_complete);
175 return;
176 }
177 spin_unlock_irqrestore(&dev->queues[i].lock, flags);
178 }
179
180 if (dev->transport->tmr_notify)
181 dev->transport->tmr_notify(dev, TMR_ABORT_TASK, &aborted_list);
182
183 printk("ABORT_TASK: Sending TMR_TASK_DOES_NOT_EXIST for ref_tag: %lld\n",
184 tmr->ref_task_tag);
185 tmr->response = TMR_TASK_DOES_NOT_EXIST;
186 atomic_long_inc(&dev->aborts_no_task);
187 }
188
core_tmr_drain_tmr_list( struct se_device *dev, struct se_tmr_req *tmr, struct list_head *preempt_and_abort_list)189 static void core_tmr_drain_tmr_list(
190 struct se_device *dev,
191 struct se_tmr_req *tmr,
192 struct list_head *preempt_and_abort_list)
193 {
194 LIST_HEAD(drain_tmr_list);
195 struct se_session *sess;
196 struct se_tmr_req *tmr_p, *tmr_pp;
197 struct se_cmd *cmd;
198 unsigned long flags;
199 bool rc;
200 /*
201 * Release all pending and outgoing TMRs aside from the received
202 * LUN_RESET tmr..
203 */
204 spin_lock_irqsave(&dev->se_tmr_lock, flags);
205 list_for_each_entry_safe(tmr_p, tmr_pp, &dev->dev_tmr_list, tmr_list) {
206 if (tmr_p == tmr)
207 continue;
208
209 cmd = tmr_p->task_cmd;
210 if (!cmd) {
211 pr_err("Unable to locate struct se_cmd for TMR\n");
212 continue;
213 }
214
215 /*
216 * We only execute one LUN_RESET at a time so we can't wait
217 * on them below.
218 */
219 if (tmr_p->function == TMR_LUN_RESET)
220 continue;
221
222 /*
223 * If this function was called with a valid pr_res_key
224 * parameter (eg: for PROUT PREEMPT_AND_ABORT service action
225 * skip non registration key matching TMRs.
226 */
227 if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
228 continue;
229
230 sess = cmd->se_sess;
231 if (WARN_ON_ONCE(!sess))
232 continue;
233
234 spin_lock(&sess->sess_cmd_lock);
235 rc = __target_check_io_state(cmd, sess, 0);
236 spin_unlock(&sess->sess_cmd_lock);
237
238 if (!rc) {
239 printk("LUN_RESET TMR: non-zero kref_get_unless_zero\n");
240 continue;
241 }
242
243 list_move_tail(&tmr_p->tmr_list, &drain_tmr_list);
244 }
245 spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
246
247 list_for_each_entry_safe(tmr_p, tmr_pp, &drain_tmr_list, tmr_list) {
248 list_del_init(&tmr_p->tmr_list);
249 cmd = tmr_p->task_cmd;
250
251 pr_debug("LUN_RESET: %s releasing TMR %p Function: 0x%02x,"
252 " Response: 0x%02x, t_state: %d\n",
253 (preempt_and_abort_list) ? "Preempt" : "", tmr_p,
254 tmr_p->function, tmr_p->response, cmd->t_state);
255
256 target_put_cmd_and_wait(cmd);
257 }
258 }
259
260 /**
261 * core_tmr_drain_state_list() - abort SCSI commands associated with a device
262 *
263 * @dev: Device for which to abort outstanding SCSI commands.
264 * @prout_cmd: Pointer to the SCSI PREEMPT AND ABORT if this function is called
265 * to realize the PREEMPT AND ABORT functionality.
266 * @tmr_sess: Session through which the LUN RESET has been received.
267 * @tas: Task Aborted Status (TAS) bit from the SCSI control mode page.
268 * A quote from SPC-4, paragraph "7.5.10 Control mode page":
269 * "A task aborted status (TAS) bit set to zero specifies that
270 * aborted commands shall be terminated by the device server
271 * without any response to the application client. A TAS bit set
272 * to one specifies that commands aborted by the actions of an I_T
273 * nexus other than the I_T nexus on which the command was
274 * received shall be completed with TASK ABORTED status."
275 * @preempt_and_abort_list: For the PREEMPT AND ABORT functionality, a list
276 * with registrations that will be preempted.
277 */
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)278 static void core_tmr_drain_state_list(
279 struct se_device *dev,
280 struct se_cmd *prout_cmd,
281 struct se_session *tmr_sess,
282 bool tas,
283 struct list_head *preempt_and_abort_list)
284 {
285 LIST_HEAD(drain_task_list);
286 struct se_session *sess;
287 struct se_cmd *cmd, *next;
288 unsigned long flags;
289 int rc, i;
290
291 /*
292 * Complete outstanding commands with TASK_ABORTED SAM status.
293 *
294 * This is following sam4r17, section 5.6 Aborting commands, Table 38
295 * for TMR LUN_RESET:
296 *
297 * a) "Yes" indicates that each command that is aborted on an I_T nexus
298 * other than the one that caused the SCSI device condition is
299 * completed with TASK ABORTED status, if the TAS bit is set to one in
300 * the Control mode page (see SPC-4). "No" indicates that no status is
301 * returned for aborted commands.
302 *
303 * d) If the logical unit reset is caused by a particular I_T nexus
304 * (e.g., by a LOGICAL UNIT RESET task management function), then "yes"
305 * (TASK_ABORTED status) applies.
306 *
307 * Otherwise (e.g., if triggered by a hard reset), "no"
308 * (no TASK_ABORTED SAM status) applies.
309 *
310 * Note that this seems to be independent of TAS (Task Aborted Status)
311 * in the Control Mode Page.
312 */
313 for (i = 0; i < dev->queue_cnt; i++) {
314 spin_lock_irqsave(&dev->queues[i].lock, flags);
315 list_for_each_entry_safe(cmd, next, &dev->queues[i].state_list,
316 state_list) {
317 /*
318 * For PREEMPT_AND_ABORT usage, only process commands
319 * with a matching reservation key.
320 */
321 if (target_check_cdb_and_preempt(preempt_and_abort_list,
322 cmd))
323 continue;
324
325 /*
326 * Not aborting PROUT PREEMPT_AND_ABORT CDB..
327 */
328 if (prout_cmd == cmd)
329 continue;
330
331 sess = cmd->se_sess;
332 if (WARN_ON_ONCE(!sess))
333 continue;
334
335 spin_lock(&sess->sess_cmd_lock);
336 rc = __target_check_io_state(cmd, tmr_sess, tas);
337 spin_unlock(&sess->sess_cmd_lock);
338 if (!rc)
339 continue;
340
341 list_move_tail(&cmd->state_list, &drain_task_list);
342 cmd->state_active = false;
343 }
344 spin_unlock_irqrestore(&dev->queues[i].lock, flags);
345 }
346
347 if (dev->transport->tmr_notify)
348 dev->transport->tmr_notify(dev, preempt_and_abort_list ?
349 TMR_LUN_RESET_PRO : TMR_LUN_RESET,
350 &drain_task_list);
351
352 while (!list_empty(&drain_task_list)) {
353 cmd = list_entry(drain_task_list.next, struct se_cmd, state_list);
354 list_del_init(&cmd->state_list);
355
356 target_show_cmd("LUN_RESET: ", cmd);
357 pr_debug("LUN_RESET: ITT[0x%08llx] - %s pr_res_key: 0x%016Lx\n",
358 cmd->tag, (preempt_and_abort_list) ? "preempt" : "",
359 cmd->pr_res_key);
360
361 target_put_cmd_and_wait(cmd);
362 }
363 }
364
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)365 int core_tmr_lun_reset(
366 struct se_device *dev,
367 struct se_tmr_req *tmr,
368 struct list_head *preempt_and_abort_list,
369 struct se_cmd *prout_cmd)
370 {
371 struct se_node_acl *tmr_nacl = NULL;
372 struct se_portal_group *tmr_tpg = NULL;
373 struct se_session *tmr_sess = NULL;
374 bool tas;
375 /*
376 * TASK_ABORTED status bit, this is configurable via ConfigFS
377 * struct se_device attributes. spc4r17 section 7.4.6 Control mode page
378 *
379 * A task aborted status (TAS) bit set to zero specifies that aborted
380 * tasks shall be terminated by the device server without any response
381 * to the application client. A TAS bit set to one specifies that tasks
382 * aborted by the actions of an I_T nexus other than the I_T nexus on
383 * which the command was received shall be completed with TASK ABORTED
384 * status (see SAM-4).
385 */
386 tas = dev->dev_attrib.emulate_tas;
387 /*
388 * Determine if this se_tmr is coming from a $FABRIC_MOD
389 * or struct se_device passthrough..
390 */
391 if (tmr && tmr->task_cmd && tmr->task_cmd->se_sess) {
392 tmr_sess = tmr->task_cmd->se_sess;
393 tmr_nacl = tmr_sess->se_node_acl;
394 tmr_tpg = tmr_sess->se_tpg;
395 if (tmr_nacl && tmr_tpg) {
396 pr_debug("LUN_RESET: TMR caller fabric: %s"
397 " initiator port %s\n",
398 tmr_tpg->se_tpg_tfo->fabric_name,
399 tmr_nacl->initiatorname);
400 }
401 }
402
403
404 /*
405 * We only allow one reset or preempt and abort to execute at a time
406 * to prevent one call from claiming all the cmds causing a second
407 * call from returning while cmds it should have waited on are still
408 * running.
409 */
410 mutex_lock(&dev->lun_reset_mutex);
411
412 pr_debug("LUN_RESET: %s starting for [%s], tas: %d\n",
413 (preempt_and_abort_list) ? "Preempt" : "TMR",
414 dev->transport->name, tas);
415 core_tmr_drain_tmr_list(dev, tmr, preempt_and_abort_list);
416 core_tmr_drain_state_list(dev, prout_cmd, tmr_sess, tas,
417 preempt_and_abort_list);
418
419 mutex_unlock(&dev->lun_reset_mutex);
420
421 /*
422 * Clear any legacy SPC-2 reservation when called during
423 * LOGICAL UNIT RESET
424 */
425 if (!preempt_and_abort_list &&
426 (dev->dev_reservation_flags & DRF_SPC2_RESERVATIONS)) {
427 spin_lock(&dev->dev_reservation_lock);
428 dev->reservation_holder = NULL;
429 dev->dev_reservation_flags &= ~DRF_SPC2_RESERVATIONS;
430 spin_unlock(&dev->dev_reservation_lock);
431 pr_debug("LUN_RESET: SCSI-2 Released reservation\n");
432 }
433
434 atomic_long_inc(&dev->num_resets);
435
436 pr_debug("LUN_RESET: %s for [%s] Complete\n",
437 (preempt_and_abort_list) ? "Preempt" : "TMR",
438 dev->transport->name);
439 return 0;
440 }
441
442