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
44 #define RTPG_FMT_MASK 0x70
45 #define RTPG_FMT_EXT_HDR 0x10
47 #define TPGS_MODE_UNINITIALIZED -1
48 #define TPGS_MODE_NONE 0x0
49 #define TPGS_MODE_IMPLICIT 0x1
50 #define TPGS_MODE_EXPLICIT 0x2
52 #define ALUA_RTPG_SIZE 128
53 #define ALUA_FAILOVER_TIMEOUT 60
54 #define ALUA_FAILOVER_RETRIES 5
55 #define ALUA_RTPG_DELAY_MSECS 5
57 /* device handler flags */
58 #define ALUA_OPTIMIZE_STPG 0x01
59 #define ALUA_RTPG_EXT_HDR_UNSUPP 0x02
60 #define ALUA_SYNC_STPG 0x04
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
;
73 static struct workqueue_struct
*kaluad_sync_wq
;
75 struct alua_port_group
{
78 struct list_head node
;
79 struct list_head dh_list
;
80 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 void 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_req_flags(sdev
, cdb
, DMA_FROM_DEVICE
,
155 buff
, bufflen
, sshdr
,
156 ALUA_FAILOVER_TIMEOUT
* HZ
,
157 ALUA_FAILOVER_RETRIES
, NULL
,
162 * submit_stpg - Issue a SET TARGET PORT GROUP command
164 * Currently we're only setting the current target port group state
165 * to 'active/optimized' and let the array firmware figure out
166 * the states of the remaining groups.
168 static int submit_stpg(struct scsi_device
*sdev
, int group_id
,
169 struct scsi_sense_hdr
*sshdr
)
171 u8 cdb
[COMMAND_SIZE(MAINTENANCE_OUT
)];
172 unsigned char stpg_data
[8];
174 int req_flags
= REQ_FAILFAST_DEV
| REQ_FAILFAST_TRANSPORT
|
177 /* Prepare the data buffer */
178 memset(stpg_data
, 0, stpg_len
);
179 stpg_data
[4] = SCSI_ACCESS_STATE_OPTIMAL
;
180 put_unaligned_be16(group_id
, &stpg_data
[6]);
182 /* Prepare the command. */
183 memset(cdb
, 0x0, COMMAND_SIZE(MAINTENANCE_OUT
));
184 cdb
[0] = MAINTENANCE_OUT
;
185 cdb
[1] = MO_SET_TARGET_PGS
;
186 put_unaligned_be32(stpg_len
, &cdb
[6]);
188 return scsi_execute_req_flags(sdev
, cdb
, DMA_TO_DEVICE
,
190 sshdr
, ALUA_FAILOVER_TIMEOUT
* HZ
,
191 ALUA_FAILOVER_RETRIES
, NULL
,
195 static struct alua_port_group
*alua_find_get_pg(char *id_str
, size_t id_size
,
198 struct alua_port_group
*pg
;
200 if (!id_str
|| !id_size
|| !strlen(id_str
))
203 list_for_each_entry(pg
, &port_group_list
, node
) {
204 if (pg
->group_id
!= group_id
)
206 if (!pg
->device_id_len
|| pg
->device_id_len
!= id_size
)
208 if (strncmp(pg
->device_id_str
, id_str
, id_size
))
210 if (!kref_get_unless_zero(&pg
->kref
))
219 * alua_alloc_pg - Allocate a new port_group structure
221 * @h: alua device_handler data
222 * @group_id: port group id
224 * Allocate a new port_group structure for a given
227 static struct alua_port_group
*alua_alloc_pg(struct scsi_device
*sdev
,
228 int group_id
, int tpgs
)
230 struct alua_port_group
*pg
, *tmp_pg
;
232 pg
= kzalloc(sizeof(struct alua_port_group
), GFP_KERNEL
);
234 return ERR_PTR(-ENOMEM
);
236 pg
->device_id_len
= scsi_vpd_lun_id(sdev
, pg
->device_id_str
,
237 sizeof(pg
->device_id_str
));
238 if (pg
->device_id_len
<= 0) {
240 * TPGS supported but no device identification found.
241 * Generate private device identification.
243 sdev_printk(KERN_INFO
, sdev
,
244 "%s: No device descriptors found\n",
246 pg
->device_id_str
[0] = '\0';
247 pg
->device_id_len
= 0;
249 pg
->group_id
= group_id
;
251 pg
->state
= SCSI_ACCESS_STATE_OPTIMAL
;
253 pg
->flags
|= ALUA_OPTIMIZE_STPG
;
254 kref_init(&pg
->kref
);
255 INIT_DELAYED_WORK(&pg
->rtpg_work
, alua_rtpg_work
);
256 INIT_LIST_HEAD(&pg
->rtpg_list
);
257 INIT_LIST_HEAD(&pg
->node
);
258 INIT_LIST_HEAD(&pg
->dh_list
);
259 spin_lock_init(&pg
->lock
);
261 spin_lock(&port_group_lock
);
262 tmp_pg
= alua_find_get_pg(pg
->device_id_str
, pg
->device_id_len
,
265 spin_unlock(&port_group_lock
);
270 list_add(&pg
->node
, &port_group_list
);
271 spin_unlock(&port_group_lock
);
277 * alua_check_tpgs - Evaluate TPGS setting
278 * @sdev: device to be checked
280 * Examine the TPGS setting of the sdev to find out if ALUA
283 static int alua_check_tpgs(struct scsi_device
*sdev
)
285 int tpgs
= TPGS_MODE_NONE
;
288 * ALUA support for non-disk devices is fraught with
289 * difficulties, so disable it for now.
291 if (sdev
->type
!= TYPE_DISK
) {
292 sdev_printk(KERN_INFO
, sdev
,
293 "%s: disable for non-disk devices\n",
298 tpgs
= scsi_device_tpgs(sdev
);
300 case TPGS_MODE_EXPLICIT
|TPGS_MODE_IMPLICIT
:
301 sdev_printk(KERN_INFO
, sdev
,
302 "%s: supports implicit and explicit TPGS\n",
305 case TPGS_MODE_EXPLICIT
:
306 sdev_printk(KERN_INFO
, sdev
, "%s: supports explicit TPGS\n",
309 case TPGS_MODE_IMPLICIT
:
310 sdev_printk(KERN_INFO
, sdev
, "%s: supports implicit TPGS\n",
314 sdev_printk(KERN_INFO
, sdev
, "%s: not supported\n",
318 sdev_printk(KERN_INFO
, sdev
,
319 "%s: unsupported TPGS setting %d\n",
321 tpgs
= TPGS_MODE_NONE
;
329 * alua_check_vpd - Evaluate INQUIRY vpd page 0x83
330 * @sdev: device to be checked
332 * Extract the relative target port and the target port group
333 * descriptor from the list of identificators.
335 static int alua_check_vpd(struct scsi_device
*sdev
, struct alua_dh_data
*h
,
338 int rel_port
= -1, group_id
;
339 struct alua_port_group
*pg
, *old_pg
= NULL
;
340 bool pg_updated
= false;
343 group_id
= scsi_vpd_tpg_id(sdev
, &rel_port
);
346 * Internal error; TPGS supported but required
347 * VPD identification descriptors not present.
348 * Disable ALUA support
350 sdev_printk(KERN_INFO
, sdev
,
351 "%s: No target port descriptors found\n",
353 return SCSI_DH_DEV_UNSUPP
;
356 pg
= alua_alloc_pg(sdev
, group_id
, tpgs
);
358 if (PTR_ERR(pg
) == -ENOMEM
)
359 return SCSI_DH_NOMEM
;
360 return SCSI_DH_DEV_UNSUPP
;
362 if (pg
->device_id_len
)
363 sdev_printk(KERN_INFO
, sdev
,
364 "%s: device %s port group %x rel port %x\n",
365 ALUA_DH_NAME
, pg
->device_id_str
,
368 sdev_printk(KERN_INFO
, sdev
,
369 "%s: port group %x rel port %x\n",
370 ALUA_DH_NAME
, group_id
, rel_port
);
372 /* Check for existing port group references */
373 spin_lock(&h
->pg_lock
);
374 old_pg
= rcu_dereference_protected(h
->pg
, lockdep_is_held(&h
->pg_lock
));
376 /* port group has changed. Update to new port group */
378 spin_lock_irqsave(&old_pg
->lock
, flags
);
379 list_del_rcu(&h
->node
);
380 spin_unlock_irqrestore(&old_pg
->lock
, flags
);
382 rcu_assign_pointer(h
->pg
, pg
);
386 spin_lock_irqsave(&pg
->lock
, flags
);
387 if (sdev
->synchronous_alua
)
388 pg
->flags
|= ALUA_SYNC_STPG
;
390 list_add_rcu(&h
->node
, &pg
->dh_list
);
391 spin_unlock_irqrestore(&pg
->lock
, flags
);
393 alua_rtpg_queue(rcu_dereference_protected(h
->pg
,
394 lockdep_is_held(&h
->pg_lock
)),
396 spin_unlock(&h
->pg_lock
);
399 kref_put(&old_pg
->kref
, release_port_group
);
404 static char print_alua_state(unsigned char state
)
407 case SCSI_ACCESS_STATE_OPTIMAL
:
409 case SCSI_ACCESS_STATE_ACTIVE
:
411 case SCSI_ACCESS_STATE_STANDBY
:
413 case SCSI_ACCESS_STATE_UNAVAILABLE
:
415 case SCSI_ACCESS_STATE_LBA
:
417 case SCSI_ACCESS_STATE_OFFLINE
:
419 case SCSI_ACCESS_STATE_TRANSITIONING
:
426 static int alua_check_sense(struct scsi_device
*sdev
,
427 struct scsi_sense_hdr
*sense_hdr
)
429 switch (sense_hdr
->sense_key
) {
431 if (sense_hdr
->asc
== 0x04 && sense_hdr
->ascq
== 0x0a) {
433 * LUN Not Accessible - ALUA state transition
435 alua_check(sdev
, false);
440 if (sense_hdr
->asc
== 0x29 && sense_hdr
->ascq
== 0x00) {
442 * Power On, Reset, or Bus Device Reset.
443 * Might have obscured a state transition,
444 * so schedule a recheck.
446 alua_check(sdev
, true);
447 return ADD_TO_MLQUEUE
;
449 if (sense_hdr
->asc
== 0x29 && sense_hdr
->ascq
== 0x04)
451 * Device internal reset
453 return ADD_TO_MLQUEUE
;
454 if (sense_hdr
->asc
== 0x2a && sense_hdr
->ascq
== 0x01)
456 * Mode Parameters Changed
458 return ADD_TO_MLQUEUE
;
459 if (sense_hdr
->asc
== 0x2a && sense_hdr
->ascq
== 0x06) {
463 alua_check(sdev
, true);
464 return ADD_TO_MLQUEUE
;
466 if (sense_hdr
->asc
== 0x2a && sense_hdr
->ascq
== 0x07) {
468 * Implicit ALUA state transition failed
470 alua_check(sdev
, true);
471 return ADD_TO_MLQUEUE
;
473 if (sense_hdr
->asc
== 0x3f && sense_hdr
->ascq
== 0x03)
475 * Inquiry data has changed
477 return ADD_TO_MLQUEUE
;
478 if (sense_hdr
->asc
== 0x3f && sense_hdr
->ascq
== 0x0e)
480 * REPORTED_LUNS_DATA_HAS_CHANGED is reported
481 * when switching controllers on targets like
482 * Intel Multi-Flex. We can just retry.
484 return ADD_TO_MLQUEUE
;
488 return SCSI_RETURN_NOT_HANDLED
;
492 * alua_tur - Send a TEST UNIT READY
493 * @sdev: device to which the TEST UNIT READY command should be send
495 * Send a TEST UNIT READY to @sdev to figure out the device state
496 * Returns SCSI_DH_RETRY if the sense code is NOT READY/ALUA TRANSITIONING,
497 * SCSI_DH_OK if no error occurred, and SCSI_DH_IO otherwise.
499 static int alua_tur(struct scsi_device
*sdev
)
501 struct scsi_sense_hdr sense_hdr
;
504 retval
= scsi_test_unit_ready(sdev
, ALUA_FAILOVER_TIMEOUT
* HZ
,
505 ALUA_FAILOVER_RETRIES
, &sense_hdr
);
506 if (sense_hdr
.sense_key
== NOT_READY
&&
507 sense_hdr
.asc
== 0x04 && sense_hdr
.ascq
== 0x0a)
508 return SCSI_DH_RETRY
;
516 * alua_rtpg - Evaluate REPORT TARGET GROUP STATES
517 * @sdev: the device to be evaluated.
519 * Evaluate the Target Port Group State.
520 * Returns SCSI_DH_DEV_OFFLINED if the path is
521 * found to be unusable.
523 static int alua_rtpg(struct scsi_device
*sdev
, struct alua_port_group
*pg
)
525 struct scsi_sense_hdr sense_hdr
;
526 struct alua_port_group
*tmp_pg
;
527 int len
, k
, off
, valid_states
= 0, bufflen
= ALUA_RTPG_SIZE
;
528 unsigned char *desc
, *buff
;
529 unsigned err
, retval
;
530 unsigned int tpg_desc_tbl_off
;
531 unsigned char orig_transition_tmo
;
535 unsigned long transition_tmo
= ALUA_FAILOVER_TIMEOUT
* HZ
;
537 if (pg
->transition_tmo
)
538 transition_tmo
= pg
->transition_tmo
* HZ
;
540 pg
->expiry
= round_jiffies_up(jiffies
+ transition_tmo
);
543 buff
= kzalloc(bufflen
, GFP_KERNEL
);
545 return SCSI_DH_DEV_TEMP_BUSY
;
549 retval
= submit_rtpg(sdev
, buff
, bufflen
, &sense_hdr
, pg
->flags
);
552 if (!scsi_sense_valid(&sense_hdr
)) {
553 sdev_printk(KERN_INFO
, sdev
,
554 "%s: rtpg failed, result %d\n",
555 ALUA_DH_NAME
, retval
);
557 if (driver_byte(retval
) == DRIVER_ERROR
)
558 return SCSI_DH_DEV_TEMP_BUSY
;
563 * submit_rtpg() has failed on existing arrays
564 * when requesting extended header info, and
565 * the array doesn't support extended headers,
566 * even though it shouldn't according to T10.
567 * The retry without rtpg_ext_hdr_req set
570 if (!(pg
->flags
& ALUA_RTPG_EXT_HDR_UNSUPP
) &&
571 sense_hdr
.sense_key
== ILLEGAL_REQUEST
&&
572 sense_hdr
.asc
== 0x24 && sense_hdr
.ascq
== 0) {
573 pg
->flags
|= ALUA_RTPG_EXT_HDR_UNSUPP
;
577 * Retry on ALUA state transition or if any
578 * UNIT ATTENTION occurred.
580 if (sense_hdr
.sense_key
== NOT_READY
&&
581 sense_hdr
.asc
== 0x04 && sense_hdr
.ascq
== 0x0a)
583 else if (sense_hdr
.sense_key
== UNIT_ATTENTION
)
585 if (err
== SCSI_DH_RETRY
&&
586 pg
->expiry
!= 0 && time_before(jiffies
, pg
->expiry
)) {
587 sdev_printk(KERN_ERR
, sdev
, "%s: rtpg retry\n",
589 scsi_print_sense_hdr(sdev
, ALUA_DH_NAME
, &sense_hdr
);
593 sdev_printk(KERN_ERR
, sdev
, "%s: rtpg failed\n",
595 scsi_print_sense_hdr(sdev
, ALUA_DH_NAME
, &sense_hdr
);
601 len
= get_unaligned_be32(&buff
[0]) + 4;
604 /* Resubmit with the correct length */
607 buff
= kmalloc(bufflen
, GFP_KERNEL
);
609 sdev_printk(KERN_WARNING
, sdev
,
610 "%s: kmalloc buffer failed\n",__func__
);
611 /* Temporary failure, bypass */
613 return SCSI_DH_DEV_TEMP_BUSY
;
618 orig_transition_tmo
= pg
->transition_tmo
;
619 if ((buff
[4] & RTPG_FMT_MASK
) == RTPG_FMT_EXT_HDR
&& buff
[5] != 0)
620 pg
->transition_tmo
= buff
[5];
622 pg
->transition_tmo
= ALUA_FAILOVER_TIMEOUT
;
624 if (orig_transition_tmo
!= pg
->transition_tmo
) {
625 sdev_printk(KERN_INFO
, sdev
,
626 "%s: transition timeout set to %d seconds\n",
627 ALUA_DH_NAME
, pg
->transition_tmo
);
628 pg
->expiry
= jiffies
+ pg
->transition_tmo
* HZ
;
631 if ((buff
[4] & RTPG_FMT_MASK
) == RTPG_FMT_EXT_HDR
)
632 tpg_desc_tbl_off
= 8;
634 tpg_desc_tbl_off
= 4;
636 for (k
= tpg_desc_tbl_off
, desc
= buff
+ tpg_desc_tbl_off
;
638 k
+= off
, desc
+= off
) {
639 u16 group_id
= get_unaligned_be16(&desc
[2]);
641 spin_lock_irqsave(&port_group_lock
, flags
);
642 tmp_pg
= alua_find_get_pg(pg
->device_id_str
, pg
->device_id_len
,
644 spin_unlock_irqrestore(&port_group_lock
, flags
);
646 if (spin_trylock_irqsave(&tmp_pg
->lock
, flags
)) {
647 if ((tmp_pg
== pg
) ||
648 !(tmp_pg
->flags
& ALUA_PG_RUNNING
)) {
649 struct alua_dh_data
*h
;
651 tmp_pg
->state
= desc
[0] & 0x0f;
652 tmp_pg
->pref
= desc
[0] >> 7;
654 list_for_each_entry_rcu(h
,
655 &tmp_pg
->dh_list
, node
) {
656 /* h->sdev should always be valid */
658 h
->sdev
->access_state
= desc
[0];
663 valid_states
= desc
[1];
664 spin_unlock_irqrestore(&tmp_pg
->lock
, flags
);
666 kref_put(&tmp_pg
->kref
, release_port_group
);
668 off
= 8 + (desc
[7] * 4);
671 spin_lock_irqsave(&pg
->lock
, flags
);
672 sdev_printk(KERN_INFO
, sdev
,
673 "%s: port group %02x state %c %s supports %c%c%c%c%c%c%c\n",
674 ALUA_DH_NAME
, pg
->group_id
, print_alua_state(pg
->state
),
675 pg
->pref
? "preferred" : "non-preferred",
676 valid_states
&TPGS_SUPPORT_TRANSITION
?'T':'t',
677 valid_states
&TPGS_SUPPORT_OFFLINE
?'O':'o',
678 valid_states
&TPGS_SUPPORT_LBA_DEPENDENT
?'L':'l',
679 valid_states
&TPGS_SUPPORT_UNAVAILABLE
?'U':'u',
680 valid_states
&TPGS_SUPPORT_STANDBY
?'S':'s',
681 valid_states
&TPGS_SUPPORT_NONOPTIMIZED
?'N':'n',
682 valid_states
&TPGS_SUPPORT_OPTIMIZED
?'A':'a');
685 case SCSI_ACCESS_STATE_TRANSITIONING
:
686 if (time_before(jiffies
, pg
->expiry
)) {
687 /* State transition, retry */
691 struct alua_dh_data
*h
;
693 /* Transitioning time exceeded, set port to standby */
695 pg
->state
= SCSI_ACCESS_STATE_STANDBY
;
698 list_for_each_entry_rcu(h
, &pg
->dh_list
, node
) {
700 h
->sdev
->access_state
=
701 (pg
->state
& SCSI_ACCESS_STATE_MASK
);
703 h
->sdev
->access_state
|=
704 SCSI_ACCESS_STATE_PREFERRED
;
709 case SCSI_ACCESS_STATE_OFFLINE
:
711 err
= SCSI_DH_DEV_OFFLINED
;
715 /* Useable path if active */
720 spin_unlock_irqrestore(&pg
->lock
, flags
);
726 * alua_stpg - Issue a SET TARGET PORT GROUP command
728 * Issue a SET TARGET PORT GROUP command and evaluate the
729 * response. Returns SCSI_DH_RETRY per default to trigger
730 * a re-evaluation of the target group state or SCSI_DH_OK
731 * if no further action needs to be taken.
733 static unsigned alua_stpg(struct scsi_device
*sdev
, struct alua_port_group
*pg
)
736 struct scsi_sense_hdr sense_hdr
;
738 if (!(pg
->tpgs
& TPGS_MODE_EXPLICIT
)) {
739 /* Only implicit ALUA supported, retry */
740 return SCSI_DH_RETRY
;
743 case SCSI_ACCESS_STATE_OPTIMAL
:
745 case SCSI_ACCESS_STATE_ACTIVE
:
746 if ((pg
->flags
& ALUA_OPTIMIZE_STPG
) &&
748 (pg
->tpgs
& TPGS_MODE_IMPLICIT
))
751 case SCSI_ACCESS_STATE_STANDBY
:
752 case SCSI_ACCESS_STATE_UNAVAILABLE
:
754 case SCSI_ACCESS_STATE_OFFLINE
:
756 case SCSI_ACCESS_STATE_TRANSITIONING
:
759 sdev_printk(KERN_INFO
, sdev
,
760 "%s: stpg failed, unhandled TPGS state %d",
761 ALUA_DH_NAME
, pg
->state
);
762 return SCSI_DH_NOSYS
;
764 retval
= submit_stpg(sdev
, pg
->group_id
, &sense_hdr
);
767 if (!scsi_sense_valid(&sense_hdr
)) {
768 sdev_printk(KERN_INFO
, sdev
,
769 "%s: stpg failed, result %d",
770 ALUA_DH_NAME
, retval
);
771 if (driver_byte(retval
) == DRIVER_ERROR
)
772 return SCSI_DH_DEV_TEMP_BUSY
;
774 sdev_printk(KERN_INFO
, sdev
, "%s: stpg failed\n",
776 scsi_print_sense_hdr(sdev
, ALUA_DH_NAME
, &sense_hdr
);
780 return SCSI_DH_RETRY
;
783 static void alua_rtpg_work(struct work_struct
*work
)
785 struct alua_port_group
*pg
=
786 container_of(work
, struct alua_port_group
, rtpg_work
.work
);
787 struct scsi_device
*sdev
;
788 LIST_HEAD(qdata_list
);
789 int err
= SCSI_DH_OK
;
790 struct alua_queue_data
*qdata
, *tmp
;
792 struct workqueue_struct
*alua_wq
= kaluad_wq
;
794 spin_lock_irqsave(&pg
->lock
, flags
);
795 sdev
= pg
->rtpg_sdev
;
797 WARN_ON(pg
->flags
& ALUA_PG_RUN_RTPG
);
798 WARN_ON(pg
->flags
& ALUA_PG_RUN_STPG
);
799 spin_unlock_irqrestore(&pg
->lock
, flags
);
800 kref_put(&pg
->kref
, release_port_group
);
803 if (pg
->flags
& ALUA_SYNC_STPG
)
804 alua_wq
= kaluad_sync_wq
;
805 pg
->flags
|= ALUA_PG_RUNNING
;
806 if (pg
->flags
& ALUA_PG_RUN_RTPG
) {
807 int state
= pg
->state
;
809 pg
->flags
&= ~ALUA_PG_RUN_RTPG
;
810 spin_unlock_irqrestore(&pg
->lock
, flags
);
811 if (state
== SCSI_ACCESS_STATE_TRANSITIONING
) {
812 if (alua_tur(sdev
) == SCSI_DH_RETRY
) {
813 spin_lock_irqsave(&pg
->lock
, flags
);
814 pg
->flags
&= ~ALUA_PG_RUNNING
;
815 pg
->flags
|= ALUA_PG_RUN_RTPG
;
816 spin_unlock_irqrestore(&pg
->lock
, flags
);
817 queue_delayed_work(alua_wq
, &pg
->rtpg_work
,
821 /* Send RTPG on failure or if TUR indicates SUCCESS */
823 err
= alua_rtpg(sdev
, pg
);
824 spin_lock_irqsave(&pg
->lock
, flags
);
825 if (err
== SCSI_DH_RETRY
|| pg
->flags
& ALUA_PG_RUN_RTPG
) {
826 pg
->flags
&= ~ALUA_PG_RUNNING
;
827 pg
->flags
|= ALUA_PG_RUN_RTPG
;
828 spin_unlock_irqrestore(&pg
->lock
, flags
);
829 queue_delayed_work(alua_wq
, &pg
->rtpg_work
,
833 if (err
!= SCSI_DH_OK
)
834 pg
->flags
&= ~ALUA_PG_RUN_STPG
;
836 if (pg
->flags
& ALUA_PG_RUN_STPG
) {
837 pg
->flags
&= ~ALUA_PG_RUN_STPG
;
838 spin_unlock_irqrestore(&pg
->lock
, flags
);
839 err
= alua_stpg(sdev
, pg
);
840 spin_lock_irqsave(&pg
->lock
, flags
);
841 if (err
== SCSI_DH_RETRY
|| pg
->flags
& ALUA_PG_RUN_RTPG
) {
842 pg
->flags
|= ALUA_PG_RUN_RTPG
;
844 pg
->flags
&= ~ALUA_PG_RUNNING
;
845 spin_unlock_irqrestore(&pg
->lock
, flags
);
846 queue_delayed_work(alua_wq
, &pg
->rtpg_work
,
852 list_splice_init(&pg
->rtpg_list
, &qdata_list
);
853 pg
->rtpg_sdev
= NULL
;
854 spin_unlock_irqrestore(&pg
->lock
, flags
);
856 list_for_each_entry_safe(qdata
, tmp
, &qdata_list
, entry
) {
857 list_del(&qdata
->entry
);
858 if (qdata
->callback_fn
)
859 qdata
->callback_fn(qdata
->callback_data
, err
);
862 spin_lock_irqsave(&pg
->lock
, flags
);
863 pg
->flags
&= ~ALUA_PG_RUNNING
;
864 spin_unlock_irqrestore(&pg
->lock
, flags
);
865 scsi_device_put(sdev
);
866 kref_put(&pg
->kref
, release_port_group
);
869 static void alua_rtpg_queue(struct alua_port_group
*pg
,
870 struct scsi_device
*sdev
,
871 struct alua_queue_data
*qdata
, bool force
)
875 struct workqueue_struct
*alua_wq
= kaluad_wq
;
880 spin_lock_irqsave(&pg
->lock
, flags
);
882 list_add_tail(&qdata
->entry
, &pg
->rtpg_list
);
883 pg
->flags
|= ALUA_PG_RUN_STPG
;
886 if (pg
->rtpg_sdev
== NULL
) {
888 pg
->flags
|= ALUA_PG_RUN_RTPG
;
890 pg
->rtpg_sdev
= sdev
;
891 scsi_device_get(sdev
);
893 } else if (!(pg
->flags
& ALUA_PG_RUN_RTPG
) && force
) {
894 pg
->flags
|= ALUA_PG_RUN_RTPG
;
895 /* Do not queue if the worker is already running */
896 if (!(pg
->flags
& ALUA_PG_RUNNING
)) {
903 if (pg
->flags
& ALUA_SYNC_STPG
)
904 alua_wq
= kaluad_sync_wq
;
905 spin_unlock_irqrestore(&pg
->lock
, flags
);
908 !queue_delayed_work(alua_wq
, &pg
->rtpg_work
,
909 msecs_to_jiffies(ALUA_RTPG_DELAY_MSECS
))) {
911 scsi_device_put(sdev
);
912 kref_put(&pg
->kref
, release_port_group
);
917 * alua_initialize - Initialize ALUA state
918 * @sdev: the device to be initialized
920 * For the prep_fn to work correctly we have
921 * to initialize the ALUA state for the device.
923 static int alua_initialize(struct scsi_device
*sdev
, struct alua_dh_data
*h
)
925 int err
= SCSI_DH_DEV_UNSUPP
, tpgs
;
927 mutex_lock(&h
->init_mutex
);
928 tpgs
= alua_check_tpgs(sdev
);
929 if (tpgs
!= TPGS_MODE_NONE
)
930 err
= alua_check_vpd(sdev
, h
, tpgs
);
932 mutex_unlock(&h
->init_mutex
);
936 * alua_set_params - set/unset the optimize flag
937 * @sdev: device on the path to be activated
938 * params - parameters in the following format
939 * "no_of_params\0param1\0param2\0param3\0...\0"
940 * For example, to set the flag pass the following parameters
941 * from multipath.conf
942 * hardware_handler "2 alua 1"
944 static int alua_set_params(struct scsi_device
*sdev
, const char *params
)
946 struct alua_dh_data
*h
= sdev
->handler_data
;
947 struct alua_port_group
*pg
= NULL
;
948 unsigned int optimize
= 0, argc
;
949 const char *p
= params
;
950 int result
= SCSI_DH_OK
;
953 if ((sscanf(params
, "%u", &argc
) != 1) || (argc
!= 1))
958 if ((sscanf(p
, "%u", &optimize
) != 1) || (optimize
> 1))
962 pg
= rcu_dereference(h
->pg
);
967 spin_lock_irqsave(&pg
->lock
, flags
);
969 pg
->flags
|= ALUA_OPTIMIZE_STPG
;
971 pg
->flags
&= ~ALUA_OPTIMIZE_STPG
;
972 spin_unlock_irqrestore(&pg
->lock
, flags
);
979 * alua_activate - activate a path
980 * @sdev: device on the path to be activated
982 * We're currently switching the port group to be activated only and
983 * let the array figure out the rest.
984 * There may be other arrays which require us to switch all port groups
985 * based on a certain policy. But until we actually encounter them it
988 static int alua_activate(struct scsi_device
*sdev
,
989 activate_complete fn
, void *data
)
991 struct alua_dh_data
*h
= sdev
->handler_data
;
992 int err
= SCSI_DH_OK
;
993 struct alua_queue_data
*qdata
;
994 struct alua_port_group
*pg
;
996 qdata
= kzalloc(sizeof(*qdata
), GFP_KERNEL
);
998 err
= SCSI_DH_RES_TEMP_UNAVAIL
;
1001 qdata
->callback_fn
= fn
;
1002 qdata
->callback_data
= data
;
1004 mutex_lock(&h
->init_mutex
);
1006 pg
= rcu_dereference(h
->pg
);
1007 if (!pg
|| !kref_get_unless_zero(&pg
->kref
)) {
1010 err
= h
->init_error
;
1011 mutex_unlock(&h
->init_mutex
);
1016 mutex_unlock(&h
->init_mutex
);
1018 alua_rtpg_queue(pg
, sdev
, qdata
, true);
1019 kref_put(&pg
->kref
, release_port_group
);
1027 * alua_check - check path status
1028 * @sdev: device on the path to be checked
1030 * Check the device status
1032 static void alua_check(struct scsi_device
*sdev
, bool force
)
1034 struct alua_dh_data
*h
= sdev
->handler_data
;
1035 struct alua_port_group
*pg
;
1038 pg
= rcu_dereference(h
->pg
);
1039 if (!pg
|| !kref_get_unless_zero(&pg
->kref
)) {
1045 alua_rtpg_queue(pg
, sdev
, NULL
, force
);
1046 kref_put(&pg
->kref
, release_port_group
);
1050 * alua_prep_fn - request callback
1052 * Fail I/O to all paths not in state
1053 * active/optimized or active/non-optimized.
1055 static int alua_prep_fn(struct scsi_device
*sdev
, struct request
*req
)
1057 struct alua_dh_data
*h
= sdev
->handler_data
;
1058 struct alua_port_group
*pg
;
1059 unsigned char state
= SCSI_ACCESS_STATE_OPTIMAL
;
1060 int ret
= BLKPREP_OK
;
1063 pg
= rcu_dereference(h
->pg
);
1067 if (state
== SCSI_ACCESS_STATE_TRANSITIONING
)
1068 ret
= BLKPREP_DEFER
;
1069 else if (state
!= SCSI_ACCESS_STATE_OPTIMAL
&&
1070 state
!= SCSI_ACCESS_STATE_ACTIVE
&&
1071 state
!= SCSI_ACCESS_STATE_LBA
) {
1073 req
->rq_flags
|= RQF_QUIET
;
1079 static void alua_rescan(struct scsi_device
*sdev
)
1081 struct alua_dh_data
*h
= sdev
->handler_data
;
1083 alua_initialize(sdev
, h
);
1087 * alua_bus_attach - Attach device handler
1088 * @sdev: device to be attached to
1090 static int alua_bus_attach(struct scsi_device
*sdev
)
1092 struct alua_dh_data
*h
;
1093 int err
, ret
= -EINVAL
;
1095 h
= kzalloc(sizeof(*h
) , GFP_KERNEL
);
1098 spin_lock_init(&h
->pg_lock
);
1099 rcu_assign_pointer(h
->pg
, NULL
);
1100 h
->init_error
= SCSI_DH_OK
;
1102 INIT_LIST_HEAD(&h
->node
);
1104 mutex_init(&h
->init_mutex
);
1105 err
= alua_initialize(sdev
, h
);
1106 if (err
== SCSI_DH_NOMEM
)
1108 if (err
!= SCSI_DH_OK
&& err
!= SCSI_DH_DEV_OFFLINED
)
1111 sdev
->handler_data
= h
;
1119 * alua_bus_detach - Detach device handler
1120 * @sdev: device to be detached from
1122 static void alua_bus_detach(struct scsi_device
*sdev
)
1124 struct alua_dh_data
*h
= sdev
->handler_data
;
1125 struct alua_port_group
*pg
;
1127 spin_lock(&h
->pg_lock
);
1128 pg
= rcu_dereference_protected(h
->pg
, lockdep_is_held(&h
->pg_lock
));
1129 rcu_assign_pointer(h
->pg
, NULL
);
1131 spin_unlock(&h
->pg_lock
);
1133 spin_lock_irq(&pg
->lock
);
1134 list_del_rcu(&h
->node
);
1135 spin_unlock_irq(&pg
->lock
);
1136 kref_put(&pg
->kref
, release_port_group
);
1138 sdev
->handler_data
= NULL
;
1142 static struct scsi_device_handler alua_dh
= {
1143 .name
= ALUA_DH_NAME
,
1144 .module
= THIS_MODULE
,
1145 .attach
= alua_bus_attach
,
1146 .detach
= alua_bus_detach
,
1147 .prep_fn
= alua_prep_fn
,
1148 .check_sense
= alua_check_sense
,
1149 .activate
= alua_activate
,
1150 .rescan
= alua_rescan
,
1151 .set_params
= alua_set_params
,
1154 static int __init
alua_init(void)
1158 kaluad_wq
= alloc_workqueue("kaluad", WQ_MEM_RECLAIM
, 0);
1160 /* Temporary failure, bypass */
1161 return SCSI_DH_DEV_TEMP_BUSY
;
1163 kaluad_sync_wq
= create_workqueue("kaluad_sync");
1164 if (!kaluad_sync_wq
) {
1165 destroy_workqueue(kaluad_wq
);
1166 return SCSI_DH_DEV_TEMP_BUSY
;
1168 r
= scsi_register_device_handler(&alua_dh
);
1170 printk(KERN_ERR
"%s: Failed to register scsi device handler",
1172 destroy_workqueue(kaluad_sync_wq
);
1173 destroy_workqueue(kaluad_wq
);
1178 static void __exit
alua_exit(void)
1180 scsi_unregister_device_handler(&alua_dh
);
1181 destroy_workqueue(kaluad_sync_wq
);
1182 destroy_workqueue(kaluad_wq
);
1185 module_init(alua_init
);
1186 module_exit(alua_exit
);
1188 MODULE_DESCRIPTION("DM Multipath ALUA support");
1189 MODULE_AUTHOR("Hannes Reinecke <hare@suse.de>");
1190 MODULE_LICENSE("GPL");
1191 MODULE_VERSION(ALUA_DH_VER
);