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