2 * Generic SCSI-3 ALUA SCSI Device Handler
4 * Copyright (C) 2007-2010 Hannes Reinecke, SUSE Linux Products GmbH.
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
22 #include <linux/slab.h>
23 #include <linux/delay.h>
24 #include <linux/module.h>
25 #include <asm/unaligned.h>
26 #include <scsi/scsi.h>
27 #include <scsi/scsi_proto.h>
28 #include <scsi/scsi_dbg.h>
29 #include <scsi/scsi_eh.h>
30 #include <scsi/scsi_dh.h>
32 #define ALUA_DH_NAME "alua"
33 #define ALUA_DH_VER "2.0"
35 #define TPGS_SUPPORT_NONE 0x00
36 #define TPGS_SUPPORT_OPTIMIZED 0x01
37 #define TPGS_SUPPORT_NONOPTIMIZED 0x02
38 #define TPGS_SUPPORT_STANDBY 0x04
39 #define TPGS_SUPPORT_UNAVAILABLE 0x08
40 #define TPGS_SUPPORT_LBA_DEPENDENT 0x10
41 #define TPGS_SUPPORT_OFFLINE 0x40
42 #define TPGS_SUPPORT_TRANSITION 0x80
43 #define TPGS_SUPPORT_ALL 0xdf
45 #define RTPG_FMT_MASK 0x70
46 #define RTPG_FMT_EXT_HDR 0x10
48 #define TPGS_MODE_UNINITIALIZED -1
49 #define TPGS_MODE_NONE 0x0
50 #define TPGS_MODE_IMPLICIT 0x1
51 #define TPGS_MODE_EXPLICIT 0x2
53 #define ALUA_RTPG_SIZE 128
54 #define ALUA_FAILOVER_TIMEOUT 60
55 #define ALUA_FAILOVER_RETRIES 5
56 #define ALUA_RTPG_DELAY_MSECS 5
58 /* device handler flags */
59 #define ALUA_OPTIMIZE_STPG 0x01
60 #define ALUA_RTPG_EXT_HDR_UNSUPP 0x02
61 /* State machine flags */
62 #define ALUA_PG_RUN_RTPG 0x10
63 #define ALUA_PG_RUN_STPG 0x20
64 #define ALUA_PG_RUNNING 0x40
66 static uint optimize_stpg
;
67 module_param(optimize_stpg
, uint
, S_IRUGO
|S_IWUSR
);
68 MODULE_PARM_DESC(optimize_stpg
, "Allow use of a non-optimized path, rather than sending a STPG, when implicit TPGS is supported (0=No,1=Yes). Default is 0.");
70 static LIST_HEAD(port_group_list
);
71 static DEFINE_SPINLOCK(port_group_lock
);
72 static struct workqueue_struct
*kaluad_wq
;
74 struct alua_port_group
{
77 struct list_head node
;
78 struct list_head dh_list
;
79 unsigned char device_id_str
[256];
86 unsigned flags
; /* used for optimizing STPG */
87 unsigned char transition_tmo
;
89 unsigned long interval
;
90 struct delayed_work rtpg_work
;
92 struct list_head rtpg_list
;
93 struct scsi_device
*rtpg_sdev
;
97 struct list_head node
;
98 struct alua_port_group __rcu
*pg
;
101 struct scsi_device
*sdev
;
103 struct mutex init_mutex
;
106 struct alua_queue_data
{
107 struct list_head entry
;
108 activate_complete callback_fn
;
112 #define ALUA_POLICY_SWITCH_CURRENT 0
113 #define ALUA_POLICY_SWITCH_ALL 1
115 static void alua_rtpg_work(struct work_struct
*work
);
116 static bool alua_rtpg_queue(struct alua_port_group
*pg
,
117 struct scsi_device
*sdev
,
118 struct alua_queue_data
*qdata
, bool force
);
119 static void alua_check(struct scsi_device
*sdev
, bool force
);
121 static void release_port_group(struct kref
*kref
)
123 struct alua_port_group
*pg
;
125 pg
= container_of(kref
, struct alua_port_group
, kref
);
127 flush_delayed_work(&pg
->rtpg_work
);
128 spin_lock(&port_group_lock
);
130 spin_unlock(&port_group_lock
);
135 * submit_rtpg - Issue a REPORT TARGET GROUP STATES command
136 * @sdev: sdev the command should be sent to
138 static int submit_rtpg(struct scsi_device
*sdev
, unsigned char *buff
,
139 int bufflen
, struct scsi_sense_hdr
*sshdr
, int flags
)
141 u8 cdb
[COMMAND_SIZE(MAINTENANCE_IN
)];
142 int req_flags
= REQ_FAILFAST_DEV
| REQ_FAILFAST_TRANSPORT
|
145 /* Prepare the command. */
146 memset(cdb
, 0x0, COMMAND_SIZE(MAINTENANCE_IN
));
147 cdb
[0] = MAINTENANCE_IN
;
148 if (!(flags
& ALUA_RTPG_EXT_HDR_UNSUPP
))
149 cdb
[1] = MI_REPORT_TARGET_PGS
| MI_EXT_HDR_PARAM_FMT
;
151 cdb
[1] = MI_REPORT_TARGET_PGS
;
152 put_unaligned_be32(bufflen
, &cdb
[6]);
154 return scsi_execute(sdev
, cdb
, DMA_FROM_DEVICE
, buff
, bufflen
, NULL
,
155 sshdr
, ALUA_FAILOVER_TIMEOUT
* HZ
,
156 ALUA_FAILOVER_RETRIES
, req_flags
, 0, NULL
);
160 * submit_stpg - Issue a SET TARGET PORT GROUP command
162 * Currently we're only setting the current target port group state
163 * to 'active/optimized' and let the array firmware figure out
164 * the states of the remaining groups.
166 static int submit_stpg(struct scsi_device
*sdev
, int group_id
,
167 struct scsi_sense_hdr
*sshdr
)
169 u8 cdb
[COMMAND_SIZE(MAINTENANCE_OUT
)];
170 unsigned char stpg_data
[8];
172 int req_flags
= REQ_FAILFAST_DEV
| REQ_FAILFAST_TRANSPORT
|
175 /* Prepare the data buffer */
176 memset(stpg_data
, 0, stpg_len
);
177 stpg_data
[4] = SCSI_ACCESS_STATE_OPTIMAL
;
178 put_unaligned_be16(group_id
, &stpg_data
[6]);
180 /* Prepare the command. */
181 memset(cdb
, 0x0, COMMAND_SIZE(MAINTENANCE_OUT
));
182 cdb
[0] = MAINTENANCE_OUT
;
183 cdb
[1] = MO_SET_TARGET_PGS
;
184 put_unaligned_be32(stpg_len
, &cdb
[6]);
186 return scsi_execute(sdev
, cdb
, DMA_TO_DEVICE
, stpg_data
, stpg_len
, NULL
,
187 sshdr
, ALUA_FAILOVER_TIMEOUT
* HZ
,
188 ALUA_FAILOVER_RETRIES
, req_flags
, 0, NULL
);
191 static struct alua_port_group
*alua_find_get_pg(char *id_str
, size_t id_size
,
194 struct alua_port_group
*pg
;
196 if (!id_str
|| !id_size
|| !strlen(id_str
))
199 list_for_each_entry(pg
, &port_group_list
, node
) {
200 if (pg
->group_id
!= group_id
)
202 if (!pg
->device_id_len
|| pg
->device_id_len
!= id_size
)
204 if (strncmp(pg
->device_id_str
, id_str
, id_size
))
206 if (!kref_get_unless_zero(&pg
->kref
))
215 * alua_alloc_pg - Allocate a new port_group structure
217 * @h: alua device_handler data
218 * @group_id: port group id
220 * Allocate a new port_group structure for a given
223 static struct alua_port_group
*alua_alloc_pg(struct scsi_device
*sdev
,
224 int group_id
, int tpgs
)
226 struct alua_port_group
*pg
, *tmp_pg
;
228 pg
= kzalloc(sizeof(struct alua_port_group
), GFP_KERNEL
);
230 return ERR_PTR(-ENOMEM
);
232 pg
->device_id_len
= scsi_vpd_lun_id(sdev
, pg
->device_id_str
,
233 sizeof(pg
->device_id_str
));
234 if (pg
->device_id_len
<= 0) {
236 * TPGS supported but no device identification found.
237 * Generate private device identification.
239 sdev_printk(KERN_INFO
, sdev
,
240 "%s: No device descriptors found\n",
242 pg
->device_id_str
[0] = '\0';
243 pg
->device_id_len
= 0;
245 pg
->group_id
= group_id
;
247 pg
->state
= SCSI_ACCESS_STATE_OPTIMAL
;
248 pg
->valid_states
= TPGS_SUPPORT_ALL
;
250 pg
->flags
|= ALUA_OPTIMIZE_STPG
;
251 kref_init(&pg
->kref
);
252 INIT_DELAYED_WORK(&pg
->rtpg_work
, alua_rtpg_work
);
253 INIT_LIST_HEAD(&pg
->rtpg_list
);
254 INIT_LIST_HEAD(&pg
->node
);
255 INIT_LIST_HEAD(&pg
->dh_list
);
256 spin_lock_init(&pg
->lock
);
258 spin_lock(&port_group_lock
);
259 tmp_pg
= alua_find_get_pg(pg
->device_id_str
, pg
->device_id_len
,
262 spin_unlock(&port_group_lock
);
267 list_add(&pg
->node
, &port_group_list
);
268 spin_unlock(&port_group_lock
);
274 * alua_check_tpgs - Evaluate TPGS setting
275 * @sdev: device to be checked
277 * Examine the TPGS setting of the sdev to find out if ALUA
280 static int alua_check_tpgs(struct scsi_device
*sdev
)
282 int tpgs
= TPGS_MODE_NONE
;
285 * ALUA support for non-disk devices is fraught with
286 * difficulties, so disable it for now.
288 if (sdev
->type
!= TYPE_DISK
) {
289 sdev_printk(KERN_INFO
, sdev
,
290 "%s: disable for non-disk devices\n",
295 tpgs
= scsi_device_tpgs(sdev
);
297 case TPGS_MODE_EXPLICIT
|TPGS_MODE_IMPLICIT
:
298 sdev_printk(KERN_INFO
, sdev
,
299 "%s: supports implicit and explicit TPGS\n",
302 case TPGS_MODE_EXPLICIT
:
303 sdev_printk(KERN_INFO
, sdev
, "%s: supports explicit TPGS\n",
306 case TPGS_MODE_IMPLICIT
:
307 sdev_printk(KERN_INFO
, sdev
, "%s: supports implicit TPGS\n",
311 sdev_printk(KERN_INFO
, sdev
, "%s: not supported\n",
315 sdev_printk(KERN_INFO
, sdev
,
316 "%s: unsupported TPGS setting %d\n",
318 tpgs
= TPGS_MODE_NONE
;
326 * alua_check_vpd - Evaluate INQUIRY vpd page 0x83
327 * @sdev: device to be checked
329 * Extract the relative target port and the target port group
330 * descriptor from the list of identificators.
332 static int alua_check_vpd(struct scsi_device
*sdev
, struct alua_dh_data
*h
,
335 int rel_port
= -1, group_id
;
336 struct alua_port_group
*pg
, *old_pg
= NULL
;
337 bool pg_updated
= false;
340 group_id
= scsi_vpd_tpg_id(sdev
, &rel_port
);
343 * Internal error; TPGS supported but required
344 * VPD identification descriptors not present.
345 * Disable ALUA support
347 sdev_printk(KERN_INFO
, sdev
,
348 "%s: No target port descriptors found\n",
350 return SCSI_DH_DEV_UNSUPP
;
353 pg
= alua_alloc_pg(sdev
, group_id
, tpgs
);
355 if (PTR_ERR(pg
) == -ENOMEM
)
356 return SCSI_DH_NOMEM
;
357 return SCSI_DH_DEV_UNSUPP
;
359 if (pg
->device_id_len
)
360 sdev_printk(KERN_INFO
, sdev
,
361 "%s: device %s port group %x rel port %x\n",
362 ALUA_DH_NAME
, pg
->device_id_str
,
365 sdev_printk(KERN_INFO
, sdev
,
366 "%s: port group %x rel port %x\n",
367 ALUA_DH_NAME
, group_id
, rel_port
);
369 /* Check for existing port group references */
370 spin_lock(&h
->pg_lock
);
371 old_pg
= rcu_dereference_protected(h
->pg
, lockdep_is_held(&h
->pg_lock
));
373 /* port group has changed. Update to new port group */
375 spin_lock_irqsave(&old_pg
->lock
, flags
);
376 list_del_rcu(&h
->node
);
377 spin_unlock_irqrestore(&old_pg
->lock
, flags
);
379 rcu_assign_pointer(h
->pg
, pg
);
383 spin_lock_irqsave(&pg
->lock
, flags
);
385 list_add_rcu(&h
->node
, &pg
->dh_list
);
386 spin_unlock_irqrestore(&pg
->lock
, flags
);
388 alua_rtpg_queue(rcu_dereference_protected(h
->pg
,
389 lockdep_is_held(&h
->pg_lock
)),
391 spin_unlock(&h
->pg_lock
);
394 kref_put(&old_pg
->kref
, release_port_group
);
399 static char print_alua_state(unsigned char state
)
402 case SCSI_ACCESS_STATE_OPTIMAL
:
404 case SCSI_ACCESS_STATE_ACTIVE
:
406 case SCSI_ACCESS_STATE_STANDBY
:
408 case SCSI_ACCESS_STATE_UNAVAILABLE
:
410 case SCSI_ACCESS_STATE_LBA
:
412 case SCSI_ACCESS_STATE_OFFLINE
:
414 case SCSI_ACCESS_STATE_TRANSITIONING
:
421 static int alua_check_sense(struct scsi_device
*sdev
,
422 struct scsi_sense_hdr
*sense_hdr
)
424 switch (sense_hdr
->sense_key
) {
426 if (sense_hdr
->asc
== 0x04 && sense_hdr
->ascq
== 0x0a) {
428 * LUN Not Accessible - ALUA state transition
430 alua_check(sdev
, false);
435 if (sense_hdr
->asc
== 0x29 && sense_hdr
->ascq
== 0x00) {
437 * Power On, Reset, or Bus Device Reset.
438 * Might have obscured a state transition,
439 * so schedule a recheck.
441 alua_check(sdev
, true);
442 return ADD_TO_MLQUEUE
;
444 if (sense_hdr
->asc
== 0x29 && sense_hdr
->ascq
== 0x04)
446 * Device internal reset
448 return ADD_TO_MLQUEUE
;
449 if (sense_hdr
->asc
== 0x2a && sense_hdr
->ascq
== 0x01)
451 * Mode Parameters Changed
453 return ADD_TO_MLQUEUE
;
454 if (sense_hdr
->asc
== 0x2a && sense_hdr
->ascq
== 0x06) {
458 alua_check(sdev
, true);
459 return ADD_TO_MLQUEUE
;
461 if (sense_hdr
->asc
== 0x2a && sense_hdr
->ascq
== 0x07) {
463 * Implicit ALUA state transition failed
465 alua_check(sdev
, true);
466 return ADD_TO_MLQUEUE
;
468 if (sense_hdr
->asc
== 0x3f && sense_hdr
->ascq
== 0x03)
470 * Inquiry data has changed
472 return ADD_TO_MLQUEUE
;
473 if (sense_hdr
->asc
== 0x3f && sense_hdr
->ascq
== 0x0e)
475 * REPORTED_LUNS_DATA_HAS_CHANGED is reported
476 * when switching controllers on targets like
477 * Intel Multi-Flex. We can just retry.
479 return ADD_TO_MLQUEUE
;
483 return SCSI_RETURN_NOT_HANDLED
;
487 * alua_tur - Send a TEST UNIT READY
488 * @sdev: device to which the TEST UNIT READY command should be send
490 * Send a TEST UNIT READY to @sdev to figure out the device state
491 * Returns SCSI_DH_RETRY if the sense code is NOT READY/ALUA TRANSITIONING,
492 * SCSI_DH_OK if no error occurred, and SCSI_DH_IO otherwise.
494 static int alua_tur(struct scsi_device
*sdev
)
496 struct scsi_sense_hdr sense_hdr
;
499 retval
= scsi_test_unit_ready(sdev
, ALUA_FAILOVER_TIMEOUT
* HZ
,
500 ALUA_FAILOVER_RETRIES
, &sense_hdr
);
501 if (sense_hdr
.sense_key
== NOT_READY
&&
502 sense_hdr
.asc
== 0x04 && sense_hdr
.ascq
== 0x0a)
503 return SCSI_DH_RETRY
;
511 * alua_rtpg - Evaluate REPORT TARGET GROUP STATES
512 * @sdev: the device to be evaluated.
514 * Evaluate the Target Port Group State.
515 * Returns SCSI_DH_DEV_OFFLINED if the path is
516 * found to be unusable.
518 static int alua_rtpg(struct scsi_device
*sdev
, struct alua_port_group
*pg
)
520 struct scsi_sense_hdr sense_hdr
;
521 struct alua_port_group
*tmp_pg
;
522 int len
, k
, off
, bufflen
= ALUA_RTPG_SIZE
;
523 unsigned char *desc
, *buff
;
524 unsigned err
, retval
;
525 unsigned int tpg_desc_tbl_off
;
526 unsigned char orig_transition_tmo
;
530 unsigned long transition_tmo
= ALUA_FAILOVER_TIMEOUT
* HZ
;
532 if (pg
->transition_tmo
)
533 transition_tmo
= pg
->transition_tmo
* HZ
;
535 pg
->expiry
= round_jiffies_up(jiffies
+ transition_tmo
);
538 buff
= kzalloc(bufflen
, GFP_KERNEL
);
540 return SCSI_DH_DEV_TEMP_BUSY
;
544 retval
= submit_rtpg(sdev
, buff
, bufflen
, &sense_hdr
, pg
->flags
);
548 * Some (broken) implementations have a habit of returning
549 * an error during things like firmware update etc.
550 * But if the target only supports active/optimized there's
551 * not much we can do; it's not that we can switch paths
553 * So ignore any errors to avoid spurious failures during
556 if ((pg
->valid_states
& ~TPGS_SUPPORT_OPTIMIZED
) == 0) {
557 sdev_printk(KERN_INFO
, sdev
,
558 "%s: ignoring rtpg result %d\n",
559 ALUA_DH_NAME
, retval
);
563 if (!scsi_sense_valid(&sense_hdr
)) {
564 sdev_printk(KERN_INFO
, sdev
,
565 "%s: rtpg failed, result %d\n",
566 ALUA_DH_NAME
, retval
);
568 if (driver_byte(retval
) == DRIVER_ERROR
)
569 return SCSI_DH_DEV_TEMP_BUSY
;
574 * submit_rtpg() has failed on existing arrays
575 * when requesting extended header info, and
576 * the array doesn't support extended headers,
577 * even though it shouldn't according to T10.
578 * The retry without rtpg_ext_hdr_req set
581 if (!(pg
->flags
& ALUA_RTPG_EXT_HDR_UNSUPP
) &&
582 sense_hdr
.sense_key
== ILLEGAL_REQUEST
&&
583 sense_hdr
.asc
== 0x24 && sense_hdr
.ascq
== 0) {
584 pg
->flags
|= ALUA_RTPG_EXT_HDR_UNSUPP
;
588 * Retry on ALUA state transition or if any
589 * UNIT ATTENTION occurred.
591 if (sense_hdr
.sense_key
== NOT_READY
&&
592 sense_hdr
.asc
== 0x04 && sense_hdr
.ascq
== 0x0a)
594 else if (sense_hdr
.sense_key
== UNIT_ATTENTION
)
596 if (err
== SCSI_DH_RETRY
&&
597 pg
->expiry
!= 0 && time_before(jiffies
, pg
->expiry
)) {
598 sdev_printk(KERN_ERR
, sdev
, "%s: rtpg retry\n",
600 scsi_print_sense_hdr(sdev
, ALUA_DH_NAME
, &sense_hdr
);
604 sdev_printk(KERN_ERR
, sdev
, "%s: rtpg failed\n",
606 scsi_print_sense_hdr(sdev
, ALUA_DH_NAME
, &sense_hdr
);
612 len
= get_unaligned_be32(&buff
[0]) + 4;
615 /* Resubmit with the correct length */
618 buff
= kmalloc(bufflen
, GFP_KERNEL
);
620 sdev_printk(KERN_WARNING
, sdev
,
621 "%s: kmalloc buffer failed\n",__func__
);
622 /* Temporary failure, bypass */
624 return SCSI_DH_DEV_TEMP_BUSY
;
629 orig_transition_tmo
= pg
->transition_tmo
;
630 if ((buff
[4] & RTPG_FMT_MASK
) == RTPG_FMT_EXT_HDR
&& buff
[5] != 0)
631 pg
->transition_tmo
= buff
[5];
633 pg
->transition_tmo
= ALUA_FAILOVER_TIMEOUT
;
635 if (orig_transition_tmo
!= pg
->transition_tmo
) {
636 sdev_printk(KERN_INFO
, sdev
,
637 "%s: transition timeout set to %d seconds\n",
638 ALUA_DH_NAME
, pg
->transition_tmo
);
639 pg
->expiry
= jiffies
+ pg
->transition_tmo
* HZ
;
642 if ((buff
[4] & RTPG_FMT_MASK
) == RTPG_FMT_EXT_HDR
)
643 tpg_desc_tbl_off
= 8;
645 tpg_desc_tbl_off
= 4;
647 for (k
= tpg_desc_tbl_off
, desc
= buff
+ tpg_desc_tbl_off
;
649 k
+= off
, desc
+= off
) {
650 u16 group_id
= get_unaligned_be16(&desc
[2]);
652 spin_lock_irqsave(&port_group_lock
, flags
);
653 tmp_pg
= alua_find_get_pg(pg
->device_id_str
, pg
->device_id_len
,
655 spin_unlock_irqrestore(&port_group_lock
, flags
);
657 if (spin_trylock_irqsave(&tmp_pg
->lock
, flags
)) {
658 if ((tmp_pg
== pg
) ||
659 !(tmp_pg
->flags
& ALUA_PG_RUNNING
)) {
660 struct alua_dh_data
*h
;
662 tmp_pg
->state
= desc
[0] & 0x0f;
663 tmp_pg
->pref
= desc
[0] >> 7;
665 list_for_each_entry_rcu(h
,
666 &tmp_pg
->dh_list
, node
) {
667 /* h->sdev should always be valid */
669 h
->sdev
->access_state
= desc
[0];
674 tmp_pg
->valid_states
= desc
[1];
675 spin_unlock_irqrestore(&tmp_pg
->lock
, flags
);
677 kref_put(&tmp_pg
->kref
, release_port_group
);
679 off
= 8 + (desc
[7] * 4);
682 spin_lock_irqsave(&pg
->lock
, flags
);
683 sdev_printk(KERN_INFO
, sdev
,
684 "%s: port group %02x state %c %s supports %c%c%c%c%c%c%c\n",
685 ALUA_DH_NAME
, pg
->group_id
, print_alua_state(pg
->state
),
686 pg
->pref
? "preferred" : "non-preferred",
687 pg
->valid_states
&TPGS_SUPPORT_TRANSITION
?'T':'t',
688 pg
->valid_states
&TPGS_SUPPORT_OFFLINE
?'O':'o',
689 pg
->valid_states
&TPGS_SUPPORT_LBA_DEPENDENT
?'L':'l',
690 pg
->valid_states
&TPGS_SUPPORT_UNAVAILABLE
?'U':'u',
691 pg
->valid_states
&TPGS_SUPPORT_STANDBY
?'S':'s',
692 pg
->valid_states
&TPGS_SUPPORT_NONOPTIMIZED
?'N':'n',
693 pg
->valid_states
&TPGS_SUPPORT_OPTIMIZED
?'A':'a');
696 case SCSI_ACCESS_STATE_TRANSITIONING
:
697 if (time_before(jiffies
, pg
->expiry
)) {
698 /* State transition, retry */
702 struct alua_dh_data
*h
;
704 /* Transitioning time exceeded, set port to standby */
706 pg
->state
= SCSI_ACCESS_STATE_STANDBY
;
709 list_for_each_entry_rcu(h
, &pg
->dh_list
, node
) {
711 h
->sdev
->access_state
=
712 (pg
->state
& SCSI_ACCESS_STATE_MASK
);
714 h
->sdev
->access_state
|=
715 SCSI_ACCESS_STATE_PREFERRED
;
720 case SCSI_ACCESS_STATE_OFFLINE
:
722 err
= SCSI_DH_DEV_OFFLINED
;
726 /* Useable path if active */
731 spin_unlock_irqrestore(&pg
->lock
, flags
);
737 * alua_stpg - Issue a SET TARGET PORT GROUP command
739 * Issue a SET TARGET PORT GROUP command and evaluate the
740 * response. Returns SCSI_DH_RETRY per default to trigger
741 * a re-evaluation of the target group state or SCSI_DH_OK
742 * if no further action needs to be taken.
744 static unsigned alua_stpg(struct scsi_device
*sdev
, struct alua_port_group
*pg
)
747 struct scsi_sense_hdr sense_hdr
;
749 if (!(pg
->tpgs
& TPGS_MODE_EXPLICIT
)) {
750 /* Only implicit ALUA supported, retry */
751 return SCSI_DH_RETRY
;
754 case SCSI_ACCESS_STATE_OPTIMAL
:
756 case SCSI_ACCESS_STATE_ACTIVE
:
757 if ((pg
->flags
& ALUA_OPTIMIZE_STPG
) &&
759 (pg
->tpgs
& TPGS_MODE_IMPLICIT
))
762 case SCSI_ACCESS_STATE_STANDBY
:
763 case SCSI_ACCESS_STATE_UNAVAILABLE
:
765 case SCSI_ACCESS_STATE_OFFLINE
:
767 case SCSI_ACCESS_STATE_TRANSITIONING
:
770 sdev_printk(KERN_INFO
, sdev
,
771 "%s: stpg failed, unhandled TPGS state %d",
772 ALUA_DH_NAME
, pg
->state
);
773 return SCSI_DH_NOSYS
;
775 retval
= submit_stpg(sdev
, pg
->group_id
, &sense_hdr
);
778 if (!scsi_sense_valid(&sense_hdr
)) {
779 sdev_printk(KERN_INFO
, sdev
,
780 "%s: stpg failed, result %d",
781 ALUA_DH_NAME
, retval
);
782 if (driver_byte(retval
) == DRIVER_ERROR
)
783 return SCSI_DH_DEV_TEMP_BUSY
;
785 sdev_printk(KERN_INFO
, sdev
, "%s: stpg failed\n",
787 scsi_print_sense_hdr(sdev
, ALUA_DH_NAME
, &sense_hdr
);
791 return SCSI_DH_RETRY
;
794 static void alua_rtpg_work(struct work_struct
*work
)
796 struct alua_port_group
*pg
=
797 container_of(work
, struct alua_port_group
, rtpg_work
.work
);
798 struct scsi_device
*sdev
;
799 LIST_HEAD(qdata_list
);
800 int err
= SCSI_DH_OK
;
801 struct alua_queue_data
*qdata
, *tmp
;
804 spin_lock_irqsave(&pg
->lock
, flags
);
805 sdev
= pg
->rtpg_sdev
;
807 WARN_ON(pg
->flags
& ALUA_PG_RUN_RTPG
);
808 WARN_ON(pg
->flags
& ALUA_PG_RUN_STPG
);
809 spin_unlock_irqrestore(&pg
->lock
, flags
);
810 kref_put(&pg
->kref
, release_port_group
);
813 pg
->flags
|= ALUA_PG_RUNNING
;
814 if (pg
->flags
& ALUA_PG_RUN_RTPG
) {
815 int state
= pg
->state
;
817 pg
->flags
&= ~ALUA_PG_RUN_RTPG
;
818 spin_unlock_irqrestore(&pg
->lock
, flags
);
819 if (state
== SCSI_ACCESS_STATE_TRANSITIONING
) {
820 if (alua_tur(sdev
) == SCSI_DH_RETRY
) {
821 spin_lock_irqsave(&pg
->lock
, flags
);
822 pg
->flags
&= ~ALUA_PG_RUNNING
;
823 pg
->flags
|= ALUA_PG_RUN_RTPG
;
824 spin_unlock_irqrestore(&pg
->lock
, flags
);
825 queue_delayed_work(kaluad_wq
, &pg
->rtpg_work
,
829 /* Send RTPG on failure or if TUR indicates SUCCESS */
831 err
= alua_rtpg(sdev
, pg
);
832 spin_lock_irqsave(&pg
->lock
, flags
);
833 if (err
== SCSI_DH_RETRY
|| pg
->flags
& ALUA_PG_RUN_RTPG
) {
834 pg
->flags
&= ~ALUA_PG_RUNNING
;
835 pg
->flags
|= ALUA_PG_RUN_RTPG
;
836 spin_unlock_irqrestore(&pg
->lock
, flags
);
837 queue_delayed_work(kaluad_wq
, &pg
->rtpg_work
,
841 if (err
!= SCSI_DH_OK
)
842 pg
->flags
&= ~ALUA_PG_RUN_STPG
;
844 if (pg
->flags
& ALUA_PG_RUN_STPG
) {
845 pg
->flags
&= ~ALUA_PG_RUN_STPG
;
846 spin_unlock_irqrestore(&pg
->lock
, flags
);
847 err
= alua_stpg(sdev
, pg
);
848 spin_lock_irqsave(&pg
->lock
, flags
);
849 if (err
== SCSI_DH_RETRY
|| pg
->flags
& ALUA_PG_RUN_RTPG
) {
850 pg
->flags
|= ALUA_PG_RUN_RTPG
;
852 pg
->flags
&= ~ALUA_PG_RUNNING
;
853 spin_unlock_irqrestore(&pg
->lock
, flags
);
854 queue_delayed_work(kaluad_wq
, &pg
->rtpg_work
,
860 list_splice_init(&pg
->rtpg_list
, &qdata_list
);
861 pg
->rtpg_sdev
= NULL
;
862 spin_unlock_irqrestore(&pg
->lock
, flags
);
864 list_for_each_entry_safe(qdata
, tmp
, &qdata_list
, entry
) {
865 list_del(&qdata
->entry
);
866 if (qdata
->callback_fn
)
867 qdata
->callback_fn(qdata
->callback_data
, err
);
870 spin_lock_irqsave(&pg
->lock
, flags
);
871 pg
->flags
&= ~ALUA_PG_RUNNING
;
872 spin_unlock_irqrestore(&pg
->lock
, flags
);
873 scsi_device_put(sdev
);
874 kref_put(&pg
->kref
, release_port_group
);
878 * alua_rtpg_queue() - cause RTPG to be submitted asynchronously
879 * @pg: ALUA port group associated with @sdev.
880 * @sdev: SCSI device for which to submit an RTPG.
881 * @qdata: Information about the callback to invoke after the RTPG.
882 * @force: Whether or not to submit an RTPG if a work item that will submit an
883 * RTPG already has been scheduled.
885 * Returns true if and only if alua_rtpg_work() will be called asynchronously.
886 * That function is responsible for calling @qdata->fn().
888 static bool alua_rtpg_queue(struct alua_port_group
*pg
,
889 struct scsi_device
*sdev
,
890 struct alua_queue_data
*qdata
, bool force
)
894 if (WARN_ON_ONCE(!pg
) || scsi_device_get(sdev
))
897 spin_lock_irqsave(&pg
->lock
, flags
);
899 list_add_tail(&qdata
->entry
, &pg
->rtpg_list
);
900 pg
->flags
|= ALUA_PG_RUN_STPG
;
903 if (pg
->rtpg_sdev
== NULL
) {
905 pg
->flags
|= ALUA_PG_RUN_RTPG
;
907 pg
->rtpg_sdev
= sdev
;
909 } else if (!(pg
->flags
& ALUA_PG_RUN_RTPG
) && force
) {
910 pg
->flags
|= ALUA_PG_RUN_RTPG
;
911 /* Do not queue if the worker is already running */
912 if (!(pg
->flags
& ALUA_PG_RUNNING
)) {
918 spin_unlock_irqrestore(&pg
->lock
, flags
);
921 if (queue_delayed_work(kaluad_wq
, &pg
->rtpg_work
,
922 msecs_to_jiffies(ALUA_RTPG_DELAY_MSECS
)))
925 kref_put(&pg
->kref
, release_port_group
);
928 scsi_device_put(sdev
);
934 * alua_initialize - Initialize ALUA state
935 * @sdev: the device to be initialized
937 * For the prep_fn to work correctly we have
938 * to initialize the ALUA state for the device.
940 static int alua_initialize(struct scsi_device
*sdev
, struct alua_dh_data
*h
)
942 int err
= SCSI_DH_DEV_UNSUPP
, tpgs
;
944 mutex_lock(&h
->init_mutex
);
945 tpgs
= alua_check_tpgs(sdev
);
946 if (tpgs
!= TPGS_MODE_NONE
)
947 err
= alua_check_vpd(sdev
, h
, tpgs
);
949 mutex_unlock(&h
->init_mutex
);
953 * alua_set_params - set/unset the optimize flag
954 * @sdev: device on the path to be activated
955 * params - parameters in the following format
956 * "no_of_params\0param1\0param2\0param3\0...\0"
957 * For example, to set the flag pass the following parameters
958 * from multipath.conf
959 * hardware_handler "2 alua 1"
961 static int alua_set_params(struct scsi_device
*sdev
, const char *params
)
963 struct alua_dh_data
*h
= sdev
->handler_data
;
964 struct alua_port_group
*pg
= NULL
;
965 unsigned int optimize
= 0, argc
;
966 const char *p
= params
;
967 int result
= SCSI_DH_OK
;
970 if ((sscanf(params
, "%u", &argc
) != 1) || (argc
!= 1))
975 if ((sscanf(p
, "%u", &optimize
) != 1) || (optimize
> 1))
979 pg
= rcu_dereference(h
->pg
);
984 spin_lock_irqsave(&pg
->lock
, flags
);
986 pg
->flags
|= ALUA_OPTIMIZE_STPG
;
988 pg
->flags
&= ~ALUA_OPTIMIZE_STPG
;
989 spin_unlock_irqrestore(&pg
->lock
, flags
);
996 * alua_activate - activate a path
997 * @sdev: device on the path to be activated
999 * We're currently switching the port group to be activated only and
1000 * let the array figure out the rest.
1001 * There may be other arrays which require us to switch all port groups
1002 * based on a certain policy. But until we actually encounter them it
1005 static int alua_activate(struct scsi_device
*sdev
,
1006 activate_complete fn
, void *data
)
1008 struct alua_dh_data
*h
= sdev
->handler_data
;
1009 int err
= SCSI_DH_OK
;
1010 struct alua_queue_data
*qdata
;
1011 struct alua_port_group
*pg
;
1013 qdata
= kzalloc(sizeof(*qdata
), GFP_KERNEL
);
1015 err
= SCSI_DH_RES_TEMP_UNAVAIL
;
1018 qdata
->callback_fn
= fn
;
1019 qdata
->callback_data
= data
;
1021 mutex_lock(&h
->init_mutex
);
1023 pg
= rcu_dereference(h
->pg
);
1024 if (!pg
|| !kref_get_unless_zero(&pg
->kref
)) {
1027 err
= h
->init_error
;
1028 mutex_unlock(&h
->init_mutex
);
1032 mutex_unlock(&h
->init_mutex
);
1034 if (alua_rtpg_queue(pg
, sdev
, qdata
, true))
1037 err
= SCSI_DH_DEV_OFFLINED
;
1038 kref_put(&pg
->kref
, release_port_group
);
1046 * alua_check - check path status
1047 * @sdev: device on the path to be checked
1049 * Check the device status
1051 static void alua_check(struct scsi_device
*sdev
, bool force
)
1053 struct alua_dh_data
*h
= sdev
->handler_data
;
1054 struct alua_port_group
*pg
;
1057 pg
= rcu_dereference(h
->pg
);
1058 if (!pg
|| !kref_get_unless_zero(&pg
->kref
)) {
1064 alua_rtpg_queue(pg
, sdev
, NULL
, force
);
1065 kref_put(&pg
->kref
, release_port_group
);
1069 * alua_prep_fn - request callback
1071 * Fail I/O to all paths not in state
1072 * active/optimized or active/non-optimized.
1074 static int alua_prep_fn(struct scsi_device
*sdev
, struct request
*req
)
1076 struct alua_dh_data
*h
= sdev
->handler_data
;
1077 struct alua_port_group
*pg
;
1078 unsigned char state
= SCSI_ACCESS_STATE_OPTIMAL
;
1079 int ret
= BLKPREP_OK
;
1082 pg
= rcu_dereference(h
->pg
);
1086 if (state
== SCSI_ACCESS_STATE_TRANSITIONING
)
1087 ret
= BLKPREP_DEFER
;
1088 else if (state
!= SCSI_ACCESS_STATE_OPTIMAL
&&
1089 state
!= SCSI_ACCESS_STATE_ACTIVE
&&
1090 state
!= SCSI_ACCESS_STATE_LBA
) {
1092 req
->rq_flags
|= RQF_QUIET
;
1098 static void alua_rescan(struct scsi_device
*sdev
)
1100 struct alua_dh_data
*h
= sdev
->handler_data
;
1102 alua_initialize(sdev
, h
);
1106 * alua_bus_attach - Attach device handler
1107 * @sdev: device to be attached to
1109 static int alua_bus_attach(struct scsi_device
*sdev
)
1111 struct alua_dh_data
*h
;
1114 h
= kzalloc(sizeof(*h
) , GFP_KERNEL
);
1116 return SCSI_DH_NOMEM
;
1117 spin_lock_init(&h
->pg_lock
);
1118 rcu_assign_pointer(h
->pg
, NULL
);
1119 h
->init_error
= SCSI_DH_OK
;
1121 INIT_LIST_HEAD(&h
->node
);
1123 mutex_init(&h
->init_mutex
);
1124 err
= alua_initialize(sdev
, h
);
1125 if (err
!= SCSI_DH_OK
&& err
!= SCSI_DH_DEV_OFFLINED
)
1128 sdev
->handler_data
= h
;
1136 * alua_bus_detach - Detach device handler
1137 * @sdev: device to be detached from
1139 static void alua_bus_detach(struct scsi_device
*sdev
)
1141 struct alua_dh_data
*h
= sdev
->handler_data
;
1142 struct alua_port_group
*pg
;
1144 spin_lock(&h
->pg_lock
);
1145 pg
= rcu_dereference_protected(h
->pg
, lockdep_is_held(&h
->pg_lock
));
1146 rcu_assign_pointer(h
->pg
, NULL
);
1148 spin_unlock(&h
->pg_lock
);
1150 spin_lock_irq(&pg
->lock
);
1151 list_del_rcu(&h
->node
);
1152 spin_unlock_irq(&pg
->lock
);
1153 kref_put(&pg
->kref
, release_port_group
);
1155 sdev
->handler_data
= NULL
;
1159 static struct scsi_device_handler alua_dh
= {
1160 .name
= ALUA_DH_NAME
,
1161 .module
= THIS_MODULE
,
1162 .attach
= alua_bus_attach
,
1163 .detach
= alua_bus_detach
,
1164 .prep_fn
= alua_prep_fn
,
1165 .check_sense
= alua_check_sense
,
1166 .activate
= alua_activate
,
1167 .rescan
= alua_rescan
,
1168 .set_params
= alua_set_params
,
1171 static int __init
alua_init(void)
1175 kaluad_wq
= alloc_workqueue("kaluad", WQ_MEM_RECLAIM
, 0);
1177 /* Temporary failure, bypass */
1178 return SCSI_DH_DEV_TEMP_BUSY
;
1181 r
= scsi_register_device_handler(&alua_dh
);
1183 printk(KERN_ERR
"%s: Failed to register scsi device handler",
1185 destroy_workqueue(kaluad_wq
);
1190 static void __exit
alua_exit(void)
1192 scsi_unregister_device_handler(&alua_dh
);
1193 destroy_workqueue(kaluad_wq
);
1196 module_init(alua_init
);
1197 module_exit(alua_exit
);
1199 MODULE_DESCRIPTION("DM Multipath ALUA support");
1200 MODULE_AUTHOR("Hannes Reinecke <hare@suse.de>");
1201 MODULE_LICENSE("GPL");
1202 MODULE_VERSION(ALUA_DH_VER
);