target: Avoid double list_del for aborted se_tmr_req
[linux-2.6.git] / drivers / target / target_core_tmr.c
1 /*******************************************************************************
2  * Filename:  target_core_tmr.c
3  *
4  * This file contains SPC-3 task management infrastructure
5  *
6  * Copyright (c) 2009,2010 Rising Tide Systems
7  * Copyright (c) 2009,2010 Linux-iSCSI.org
8  *
9  * Nicholas A. Bellinger <nab@kernel.org>
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License as published by
13  * the Free Software Foundation; either version 2 of the License, or
14  * (at your option) any later version.
15  *
16  * This program is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
19  * GNU General Public License for more details.
20  *
21  * You should have received a copy of the GNU General Public License
22  * along with this program; if not, write to the Free Software
23  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
24  *
25  ******************************************************************************/
26
27 #include <linux/slab.h>
28 #include <linux/spinlock.h>
29 #include <linux/list.h>
30 #include <scsi/scsi.h>
31 #include <scsi/scsi_cmnd.h>
32
33 #include <target/target_core_base.h>
34 #include <target/target_core_device.h>
35 #include <target/target_core_tmr.h>
36 #include <target/target_core_transport.h>
37 #include <target/target_core_fabric_ops.h>
38 #include <target/target_core_configfs.h>
39
40 #include "target_core_alua.h"
41 #include "target_core_pr.h"
42
43 struct se_tmr_req *core_tmr_alloc_req(
44         struct se_cmd *se_cmd,
45         void *fabric_tmr_ptr,
46         u8 function,
47         gfp_t gfp_flags)
48 {
49         struct se_tmr_req *tmr;
50
51         tmr = kmem_cache_zalloc(se_tmr_req_cache, gfp_flags);
52         if (!tmr) {
53                 pr_err("Unable to allocate struct se_tmr_req\n");
54                 return ERR_PTR(-ENOMEM);
55         }
56         tmr->task_cmd = se_cmd;
57         tmr->fabric_tmr_ptr = fabric_tmr_ptr;
58         tmr->function = function;
59         INIT_LIST_HEAD(&tmr->tmr_list);
60
61         return tmr;
62 }
63 EXPORT_SYMBOL(core_tmr_alloc_req);
64
65 void core_tmr_release_req(
66         struct se_tmr_req *tmr)
67 {
68         struct se_device *dev = tmr->tmr_dev;
69         unsigned long flags;
70
71         if (!dev) {
72                 kmem_cache_free(se_tmr_req_cache, tmr);
73                 return;
74         }
75
76         spin_lock_irqsave(&dev->se_tmr_lock, flags);
77         list_del(&tmr->tmr_list);
78         spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
79
80         kmem_cache_free(se_tmr_req_cache, tmr);
81 }
82
83 static void core_tmr_handle_tas_abort(
84         struct se_node_acl *tmr_nacl,
85         struct se_cmd *cmd,
86         int tas,
87         int fe_count)
88 {
89         if (!fe_count) {
90                 transport_cmd_finish_abort(cmd, 1);
91                 return;
92         }
93         /*
94          * TASK ABORTED status (TAS) bit support
95         */
96         if ((tmr_nacl &&
97              (tmr_nacl == cmd->se_sess->se_node_acl)) || tas)
98                 transport_send_task_abort(cmd);
99
100         transport_cmd_finish_abort(cmd, 0);
101 }
102
103 static void core_tmr_drain_tmr_list(
104         struct se_device *dev,
105         struct se_tmr_req *tmr,
106         struct list_head *preempt_and_abort_list)
107 {
108         LIST_HEAD(drain_tmr_list);
109         struct se_tmr_req *tmr_p, *tmr_pp;
110         struct se_cmd *cmd;
111         unsigned long flags;
112         /*
113          * Release all pending and outgoing TMRs aside from the received
114          * LUN_RESET tmr..
115          */
116         spin_lock_irqsave(&dev->se_tmr_lock, flags);
117         list_for_each_entry_safe(tmr_p, tmr_pp, &dev->dev_tmr_list, tmr_list) {
118                 /*
119                  * Allow the received TMR to return with FUNCTION_COMPLETE.
120                  */
121                 if (tmr_p == tmr)
122                         continue;
123
124                 cmd = tmr_p->task_cmd;
125                 if (!cmd) {
126                         pr_err("Unable to locate struct se_cmd for TMR\n");
127                         continue;
128                 }
129                 /*
130                  * If this function was called with a valid pr_res_key
131                  * parameter (eg: for PROUT PREEMPT_AND_ABORT service action
132                  * skip non regisration key matching TMRs.
133                  */
134                 if (preempt_and_abort_list &&
135                     (core_scsi3_check_cdb_abort_and_preempt(
136                                         preempt_and_abort_list, cmd) != 0))
137                         continue;
138
139                 spin_lock(&cmd->t_state_lock);
140                 if (!atomic_read(&cmd->t_transport_active)) {
141                         spin_unlock(&cmd->t_state_lock);
142                         continue;
143                 }
144                 if (cmd->t_state == TRANSPORT_ISTATE_PROCESSING) {
145                         spin_unlock(&cmd->t_state_lock);
146                         continue;
147                 }
148                 spin_unlock(&cmd->t_state_lock);
149
150                 list_move_tail(&tmr_p->tmr_list, &drain_tmr_list);
151         }
152         spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
153
154         list_for_each_entry_safe(tmr_p, tmr_pp, &drain_tmr_list, tmr_list) {
155                 list_del_init(&tmr_p->tmr_list);
156                 cmd = tmr_p->task_cmd;
157
158                 pr_debug("LUN_RESET: %s releasing TMR %p Function: 0x%02x,"
159                         " Response: 0x%02x, t_state: %d\n",
160                         (preempt_and_abort_list) ? "Preempt" : "", tmr_p,
161                         tmr_p->function, tmr_p->response, cmd->t_state);
162
163                 transport_cmd_finish_abort(cmd, 1);
164         }
165 }
166
167 static void core_tmr_drain_task_list(
168         struct se_device *dev,
169         struct se_cmd *prout_cmd,
170         struct se_node_acl *tmr_nacl,
171         int tas,
172         struct list_head *preempt_and_abort_list)
173 {
174         LIST_HEAD(drain_task_list);
175         struct se_cmd *cmd;
176         struct se_task *task, *task_tmp;
177         unsigned long flags;
178         int fe_count;
179         /*
180          * Complete outstanding struct se_task CDBs with TASK_ABORTED SAM status.
181          * This is following sam4r17, section 5.6 Aborting commands, Table 38
182          * for TMR LUN_RESET:
183          *
184          * a) "Yes" indicates that each command that is aborted on an I_T nexus
185          * other than the one that caused the SCSI device condition is
186          * completed with TASK ABORTED status, if the TAS bit is set to one in
187          * the Control mode page (see SPC-4). "No" indicates that no status is
188          * returned for aborted commands.
189          *
190          * d) If the logical unit reset is caused by a particular I_T nexus
191          * (e.g., by a LOGICAL UNIT RESET task management function), then "yes"
192          * (TASK_ABORTED status) applies.
193          *
194          * Otherwise (e.g., if triggered by a hard reset), "no"
195          * (no TASK_ABORTED SAM status) applies.
196          *
197          * Note that this seems to be independent of TAS (Task Aborted Status)
198          * in the Control Mode Page.
199          */
200         spin_lock_irqsave(&dev->execute_task_lock, flags);
201         list_for_each_entry_safe(task, task_tmp, &dev->state_task_list,
202                                 t_state_list) {
203                 if (!task->task_se_cmd) {
204                         pr_err("task->task_se_cmd is NULL!\n");
205                         continue;
206                 }
207                 cmd = task->task_se_cmd;
208
209                 /*
210                  * For PREEMPT_AND_ABORT usage, only process commands
211                  * with a matching reservation key.
212                  */
213                 if (preempt_and_abort_list &&
214                     (core_scsi3_check_cdb_abort_and_preempt(
215                                         preempt_and_abort_list, cmd) != 0))
216                         continue;
217                 /*
218                  * Not aborting PROUT PREEMPT_AND_ABORT CDB..
219                  */
220                 if (prout_cmd == cmd)
221                         continue;
222
223                 list_move_tail(&task->t_state_list, &drain_task_list);
224                 atomic_set(&task->task_state_active, 0);
225                 /*
226                  * Remove from task execute list before processing drain_task_list
227                  */
228                 if (!list_empty(&task->t_execute_list))
229                         __transport_remove_task_from_execute_queue(task, dev);
230         }
231         spin_unlock_irqrestore(&dev->execute_task_lock, flags);
232
233         while (!list_empty(&drain_task_list)) {
234                 task = list_entry(drain_task_list.next, struct se_task, t_state_list);
235                 list_del(&task->t_state_list);
236                 cmd = task->task_se_cmd;
237
238                 pr_debug("LUN_RESET: %s cmd: %p task: %p"
239                         " ITT/CmdSN: 0x%08x/0x%08x, i_state: %d, t_state: %d"
240                         "cdb: 0x%02x\n",
241                         (preempt_and_abort_list) ? "Preempt" : "", cmd, task,
242                         cmd->se_tfo->get_task_tag(cmd), 0,
243                         cmd->se_tfo->get_cmd_state(cmd), cmd->t_state,
244                         cmd->t_task_cdb[0]);
245                 pr_debug("LUN_RESET: ITT[0x%08x] - pr_res_key: 0x%016Lx"
246                         " t_task_cdbs: %d t_task_cdbs_left: %d"
247                         " t_task_cdbs_sent: %d -- t_transport_active: %d"
248                         " t_transport_stop: %d t_transport_sent: %d\n",
249                         cmd->se_tfo->get_task_tag(cmd), cmd->pr_res_key,
250                         cmd->t_task_list_num,
251                         atomic_read(&cmd->t_task_cdbs_left),
252                         atomic_read(&cmd->t_task_cdbs_sent),
253                         atomic_read(&cmd->t_transport_active),
254                         atomic_read(&cmd->t_transport_stop),
255                         atomic_read(&cmd->t_transport_sent));
256
257                 /*
258                  * If the command may be queued onto a workqueue cancel it now.
259                  *
260                  * This is equivalent to removal from the execute queue in the
261                  * loop above, but we do it down here given that
262                  * cancel_work_sync may block.
263                  */
264                 if (cmd->t_state == TRANSPORT_COMPLETE)
265                         cancel_work_sync(&cmd->work);
266
267                 spin_lock_irqsave(&cmd->t_state_lock, flags);
268                 target_stop_task(task, &flags);
269
270                 if (!atomic_dec_and_test(&cmd->t_task_cdbs_ex_left)) {
271                         spin_unlock_irqrestore(&cmd->t_state_lock, flags);
272                         pr_debug("LUN_RESET: Skipping task: %p, dev: %p for"
273                                 " t_task_cdbs_ex_left: %d\n", task, dev,
274                                 atomic_read(&cmd->t_task_cdbs_ex_left));
275                         continue;
276                 }
277                 fe_count = atomic_read(&cmd->t_fe_count);
278
279                 if (atomic_read(&cmd->t_transport_active)) {
280                         pr_debug("LUN_RESET: got t_transport_active = 1 for"
281                                 " task: %p, t_fe_count: %d dev: %p\n", task,
282                                 fe_count, dev);
283                         atomic_set(&cmd->t_transport_aborted, 1);
284                         spin_unlock_irqrestore(&cmd->t_state_lock, flags);
285
286                         core_tmr_handle_tas_abort(tmr_nacl, cmd, tas, fe_count);
287                         continue;
288                 }
289                 pr_debug("LUN_RESET: Got t_transport_active = 0 for task: %p,"
290                         " t_fe_count: %d dev: %p\n", task, fe_count, dev);
291                 atomic_set(&cmd->t_transport_aborted, 1);
292                 spin_unlock_irqrestore(&cmd->t_state_lock, flags);
293
294                 core_tmr_handle_tas_abort(tmr_nacl, cmd, tas, fe_count);
295         }
296 }
297
298 static void core_tmr_drain_cmd_list(
299         struct se_device *dev,
300         struct se_cmd *prout_cmd,
301         struct se_node_acl *tmr_nacl,
302         int tas,
303         struct list_head *preempt_and_abort_list)
304 {
305         LIST_HEAD(drain_cmd_list);
306         struct se_queue_obj *qobj = &dev->dev_queue_obj;
307         struct se_cmd *cmd, *tcmd;
308         unsigned long flags;
309         /*
310          * Release all commands remaining in the struct se_device cmd queue.
311          *
312          * This follows the same logic as above for the struct se_device
313          * struct se_task state list, where commands are returned with
314          * TASK_ABORTED status, if there is an outstanding $FABRIC_MOD
315          * reference, otherwise the struct se_cmd is released.
316          */
317         spin_lock_irqsave(&qobj->cmd_queue_lock, flags);
318         list_for_each_entry_safe(cmd, tcmd, &qobj->qobj_list, se_queue_node) {
319                 /*
320                  * For PREEMPT_AND_ABORT usage, only process commands
321                  * with a matching reservation key.
322                  */
323                 if (preempt_and_abort_list &&
324                     (core_scsi3_check_cdb_abort_and_preempt(
325                                         preempt_and_abort_list, cmd) != 0))
326                         continue;
327                 /*
328                  * Not aborting PROUT PREEMPT_AND_ABORT CDB..
329                  */
330                 if (prout_cmd == cmd)
331                         continue;
332                 /*
333                  * Skip direct processing of TRANSPORT_FREE_CMD_INTR for
334                  * HW target mode fabrics.
335                  */
336                 spin_lock(&cmd->t_state_lock);
337                 if (cmd->t_state == TRANSPORT_FREE_CMD_INTR) {
338                         spin_unlock(&cmd->t_state_lock);
339                         continue;
340                 }
341                 spin_unlock(&cmd->t_state_lock);
342
343                 atomic_set(&cmd->t_transport_queue_active, 0);
344                 atomic_dec(&qobj->queue_cnt);
345                 list_move_tail(&cmd->se_queue_node, &drain_cmd_list);
346         }
347         spin_unlock_irqrestore(&qobj->cmd_queue_lock, flags);
348
349         while (!list_empty(&drain_cmd_list)) {
350                 cmd = list_entry(drain_cmd_list.next, struct se_cmd, se_queue_node);
351                 list_del_init(&cmd->se_queue_node);
352
353                 pr_debug("LUN_RESET: %s from Device Queue: cmd: %p t_state:"
354                         " %d t_fe_count: %d\n", (preempt_and_abort_list) ?
355                         "Preempt" : "", cmd, cmd->t_state,
356                         atomic_read(&cmd->t_fe_count));
357                 /*
358                  * Signal that the command has failed via cmd->se_cmd_flags,
359                  */
360                 transport_new_cmd_failure(cmd);
361
362                 core_tmr_handle_tas_abort(tmr_nacl, cmd, tas,
363                                 atomic_read(&cmd->t_fe_count));
364         }
365 }
366
367 int core_tmr_lun_reset(
368         struct se_device *dev,
369         struct se_tmr_req *tmr,
370         struct list_head *preempt_and_abort_list,
371         struct se_cmd *prout_cmd)
372 {
373         struct se_node_acl *tmr_nacl = NULL;
374         struct se_portal_group *tmr_tpg = NULL;
375         int tas;
376         /*
377          * TASK_ABORTED status bit, this is configurable via ConfigFS
378          * struct se_device attributes.  spc4r17 section 7.4.6 Control mode page
379          *
380          * A task aborted status (TAS) bit set to zero specifies that aborted
381          * tasks shall be terminated by the device server without any response
382          * to the application client. A TAS bit set to one specifies that tasks
383          * aborted by the actions of an I_T nexus other than the I_T nexus on
384          * which the command was received shall be completed with TASK ABORTED
385          * status (see SAM-4).
386          */
387         tas = dev->se_sub_dev->se_dev_attrib.emulate_tas;
388         /*
389          * Determine if this se_tmr is coming from a $FABRIC_MOD
390          * or struct se_device passthrough..
391          */
392         if (tmr && tmr->task_cmd && tmr->task_cmd->se_sess) {
393                 tmr_nacl = tmr->task_cmd->se_sess->se_node_acl;
394                 tmr_tpg = tmr->task_cmd->se_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->get_fabric_name(),
399                                 tmr_nacl->initiatorname);
400                 }
401         }
402         pr_debug("LUN_RESET: %s starting for [%s], tas: %d\n",
403                 (preempt_and_abort_list) ? "Preempt" : "TMR",
404                 dev->transport->name, tas);
405
406         core_tmr_drain_tmr_list(dev, tmr, preempt_and_abort_list);
407         core_tmr_drain_task_list(dev, prout_cmd, tmr_nacl, tas,
408                                 preempt_and_abort_list);
409         core_tmr_drain_cmd_list(dev, prout_cmd, tmr_nacl, tas,
410                                 preempt_and_abort_list);
411         /*
412          * Clear any legacy SPC-2 reservation when called during
413          * LOGICAL UNIT RESET
414          */
415         if (!preempt_and_abort_list &&
416              (dev->dev_flags & DF_SPC2_RESERVATIONS)) {
417                 spin_lock(&dev->dev_reservation_lock);
418                 dev->dev_reserved_node_acl = NULL;
419                 dev->dev_flags &= ~DF_SPC2_RESERVATIONS;
420                 spin_unlock(&dev->dev_reservation_lock);
421                 pr_debug("LUN_RESET: SCSI-2 Released reservation\n");
422         }
423
424         spin_lock_irq(&dev->stats_lock);
425         dev->num_resets++;
426         spin_unlock_irq(&dev->stats_lock);
427
428         pr_debug("LUN_RESET: %s for [%s] Complete\n",
429                         (preempt_and_abort_list) ? "Preempt" : "TMR",
430                         dev->transport->name);
431         return 0;
432 }
433