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,int tas)80 static bool __target_check_io_state(struct se_cmd *se_cmd,
81 struct se_session *tmr_sess, int 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 struct se_cmd *se_cmd;
120 unsigned long flags;
121 u64 ref_tag;
122
123 spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
124 list_for_each_entry(se_cmd, &se_sess->sess_cmd_list, se_cmd_list) {
125
126 if (dev != se_cmd->se_dev)
127 continue;
128
129 /* skip task management functions, including tmr->task_cmd */
130 if (se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
131 continue;
132
133 ref_tag = se_cmd->tag;
134 if (tmr->ref_task_tag != ref_tag)
135 continue;
136
137 printk("ABORT_TASK: Found referenced %s task_tag: %llu\n",
138 se_cmd->se_tfo->fabric_name, ref_tag);
139
140 if (!__target_check_io_state(se_cmd, se_sess,
141 dev->dev_attrib.emulate_tas))
142 continue;
143
144 spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
145
146 /*
147 * Ensure that this ABORT request is visible to the LU RESET
148 * code.
149 */
150 if (!tmr->tmr_dev)
151 WARN_ON_ONCE(transport_lookup_tmr_lun(tmr->task_cmd,
152 se_cmd->orig_fe_lun) < 0);
153
154 target_put_cmd_and_wait(se_cmd);
155
156 printk("ABORT_TASK: Sending TMR_FUNCTION_COMPLETE for"
157 " ref_tag: %llu\n", ref_tag);
158 tmr->response = TMR_FUNCTION_COMPLETE;
159 atomic_long_inc(&dev->aborts_complete);
160 return;
161 }
162 spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
163
164 printk("ABORT_TASK: Sending TMR_TASK_DOES_NOT_EXIST for ref_tag: %lld\n",
165 tmr->ref_task_tag);
166 tmr->response = TMR_TASK_DOES_NOT_EXIST;
167 atomic_long_inc(&dev->aborts_no_task);
168 }
169
core_tmr_drain_tmr_list(struct se_device * dev,struct se_tmr_req * tmr,struct list_head * preempt_and_abort_list)170 static void core_tmr_drain_tmr_list(
171 struct se_device *dev,
172 struct se_tmr_req *tmr,
173 struct list_head *preempt_and_abort_list)
174 {
175 LIST_HEAD(drain_tmr_list);
176 struct se_session *sess;
177 struct se_tmr_req *tmr_p, *tmr_pp;
178 struct se_cmd *cmd;
179 unsigned long flags;
180 bool rc;
181 /*
182 * Release all pending and outgoing TMRs aside from the received
183 * LUN_RESET tmr..
184 */
185 spin_lock_irqsave(&dev->se_tmr_lock, flags);
186 if (tmr)
187 list_del_init(&tmr->tmr_list);
188 list_for_each_entry_safe(tmr_p, tmr_pp, &dev->dev_tmr_list, tmr_list) {
189 cmd = tmr_p->task_cmd;
190 if (!cmd) {
191 pr_err("Unable to locate struct se_cmd for TMR\n");
192 continue;
193 }
194 /*
195 * If this function was called with a valid pr_res_key
196 * parameter (eg: for PROUT PREEMPT_AND_ABORT service action
197 * skip non registration key matching TMRs.
198 */
199 if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
200 continue;
201
202 sess = cmd->se_sess;
203 if (WARN_ON_ONCE(!sess))
204 continue;
205
206 spin_lock(&sess->sess_cmd_lock);
207 rc = __target_check_io_state(cmd, sess, 0);
208 spin_unlock(&sess->sess_cmd_lock);
209
210 if (!rc) {
211 printk("LUN_RESET TMR: non-zero kref_get_unless_zero\n");
212 continue;
213 }
214
215 list_move_tail(&tmr_p->tmr_list, &drain_tmr_list);
216 }
217 spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
218
219 list_for_each_entry_safe(tmr_p, tmr_pp, &drain_tmr_list, tmr_list) {
220 list_del_init(&tmr_p->tmr_list);
221 cmd = tmr_p->task_cmd;
222
223 pr_debug("LUN_RESET: %s releasing TMR %p Function: 0x%02x,"
224 " Response: 0x%02x, t_state: %d\n",
225 (preempt_and_abort_list) ? "Preempt" : "", tmr_p,
226 tmr_p->function, tmr_p->response, cmd->t_state);
227
228 target_put_cmd_and_wait(cmd);
229 }
230 }
231
232 /**
233 * core_tmr_drain_state_list() - abort SCSI commands associated with a device
234 *
235 * @dev: Device for which to abort outstanding SCSI commands.
236 * @prout_cmd: Pointer to the SCSI PREEMPT AND ABORT if this function is called
237 * to realize the PREEMPT AND ABORT functionality.
238 * @tmr_sess: Session through which the LUN RESET has been received.
239 * @tas: Task Aborted Status (TAS) bit from the SCSI control mode page.
240 * A quote from SPC-4, paragraph "7.5.10 Control mode page":
241 * "A task aborted status (TAS) bit set to zero specifies that
242 * aborted commands shall be terminated by the device server
243 * without any response to the application client. A TAS bit set
244 * to one specifies that commands aborted by the actions of an I_T
245 * nexus other than the I_T nexus on which the command was
246 * received shall be completed with TASK ABORTED status."
247 * @preempt_and_abort_list: For the PREEMPT AND ABORT functionality, a list
248 * with registrations that will be preempted.
249 */
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)250 static void core_tmr_drain_state_list(
251 struct se_device *dev,
252 struct se_cmd *prout_cmd,
253 struct se_session *tmr_sess,
254 int tas,
255 struct list_head *preempt_and_abort_list)
256 {
257 LIST_HEAD(drain_task_list);
258 struct se_session *sess;
259 struct se_cmd *cmd, *next;
260 unsigned long flags;
261 int rc;
262
263 /*
264 * Complete outstanding commands with TASK_ABORTED SAM status.
265 *
266 * This is following sam4r17, section 5.6 Aborting commands, Table 38
267 * for TMR LUN_RESET:
268 *
269 * a) "Yes" indicates that each command that is aborted on an I_T nexus
270 * other than the one that caused the SCSI device condition is
271 * completed with TASK ABORTED status, if the TAS bit is set to one in
272 * the Control mode page (see SPC-4). "No" indicates that no status is
273 * returned for aborted commands.
274 *
275 * d) If the logical unit reset is caused by a particular I_T nexus
276 * (e.g., by a LOGICAL UNIT RESET task management function), then "yes"
277 * (TASK_ABORTED status) applies.
278 *
279 * Otherwise (e.g., if triggered by a hard reset), "no"
280 * (no TASK_ABORTED SAM status) applies.
281 *
282 * Note that this seems to be independent of TAS (Task Aborted Status)
283 * in the Control Mode Page.
284 */
285 spin_lock_irqsave(&dev->execute_task_lock, flags);
286 list_for_each_entry_safe(cmd, next, &dev->state_list, state_list) {
287 /*
288 * For PREEMPT_AND_ABORT usage, only process commands
289 * with a matching reservation key.
290 */
291 if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
292 continue;
293
294 /*
295 * Not aborting PROUT PREEMPT_AND_ABORT CDB..
296 */
297 if (prout_cmd == cmd)
298 continue;
299
300 sess = cmd->se_sess;
301 if (WARN_ON_ONCE(!sess))
302 continue;
303
304 spin_lock(&sess->sess_cmd_lock);
305 rc = __target_check_io_state(cmd, tmr_sess, tas);
306 spin_unlock(&sess->sess_cmd_lock);
307 if (!rc)
308 continue;
309
310 list_move_tail(&cmd->state_list, &drain_task_list);
311 cmd->state_active = false;
312 }
313 spin_unlock_irqrestore(&dev->execute_task_lock, flags);
314
315 while (!list_empty(&drain_task_list)) {
316 cmd = list_entry(drain_task_list.next, struct se_cmd, state_list);
317 list_del_init(&cmd->state_list);
318
319 target_show_cmd("LUN_RESET: ", cmd);
320 pr_debug("LUN_RESET: ITT[0x%08llx] - %s pr_res_key: 0x%016Lx\n",
321 cmd->tag, (preempt_and_abort_list) ? "preempt" : "",
322 cmd->pr_res_key);
323
324 target_put_cmd_and_wait(cmd);
325 }
326 }
327
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)328 int core_tmr_lun_reset(
329 struct se_device *dev,
330 struct se_tmr_req *tmr,
331 struct list_head *preempt_and_abort_list,
332 struct se_cmd *prout_cmd)
333 {
334 struct se_node_acl *tmr_nacl = NULL;
335 struct se_portal_group *tmr_tpg = NULL;
336 struct se_session *tmr_sess = NULL;
337 int tas;
338 /*
339 * TASK_ABORTED status bit, this is configurable via ConfigFS
340 * struct se_device attributes. spc4r17 section 7.4.6 Control mode page
341 *
342 * A task aborted status (TAS) bit set to zero specifies that aborted
343 * tasks shall be terminated by the device server without any response
344 * to the application client. A TAS bit set to one specifies that tasks
345 * aborted by the actions of an I_T nexus other than the I_T nexus on
346 * which the command was received shall be completed with TASK ABORTED
347 * status (see SAM-4).
348 */
349 tas = dev->dev_attrib.emulate_tas;
350 /*
351 * Determine if this se_tmr is coming from a $FABRIC_MOD
352 * or struct se_device passthrough..
353 */
354 if (tmr && tmr->task_cmd && tmr->task_cmd->se_sess) {
355 tmr_sess = tmr->task_cmd->se_sess;
356 tmr_nacl = tmr_sess->se_node_acl;
357 tmr_tpg = tmr_sess->se_tpg;
358 if (tmr_nacl && tmr_tpg) {
359 pr_debug("LUN_RESET: TMR caller fabric: %s"
360 " initiator port %s\n",
361 tmr_tpg->se_tpg_tfo->fabric_name,
362 tmr_nacl->initiatorname);
363 }
364 }
365 pr_debug("LUN_RESET: %s starting for [%s], tas: %d\n",
366 (preempt_and_abort_list) ? "Preempt" : "TMR",
367 dev->transport->name, tas);
368
369 core_tmr_drain_tmr_list(dev, tmr, preempt_and_abort_list);
370 core_tmr_drain_state_list(dev, prout_cmd, tmr_sess, tas,
371 preempt_and_abort_list);
372
373 /*
374 * Clear any legacy SPC-2 reservation when called during
375 * LOGICAL UNIT RESET
376 */
377 if (!preempt_and_abort_list &&
378 (dev->dev_reservation_flags & DRF_SPC2_RESERVATIONS)) {
379 spin_lock(&dev->dev_reservation_lock);
380 dev->reservation_holder = NULL;
381 dev->dev_reservation_flags &= ~DRF_SPC2_RESERVATIONS;
382 spin_unlock(&dev->dev_reservation_lock);
383 pr_debug("LUN_RESET: SCSI-2 Released reservation\n");
384 }
385
386 atomic_long_inc(&dev->num_resets);
387
388 pr_debug("LUN_RESET: %s for [%s] Complete\n",
389 (preempt_and_abort_list) ? "Preempt" : "TMR",
390 dev->transport->name);
391 return 0;
392 }
393
394