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