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 <scsi/scsi.h>
26 #include <scsi/scsi_eh.h>
27 #include <scsi/scsi_dh.h>
29 #define ALUA_DH_NAME "alua"
30 #define ALUA_DH_VER "1.3"
32 #define TPGS_STATE_OPTIMIZED 0x0
33 #define TPGS_STATE_NONOPTIMIZED 0x1
34 #define TPGS_STATE_STANDBY 0x2
35 #define TPGS_STATE_UNAVAILABLE 0x3
36 #define TPGS_STATE_LBA_DEPENDENT 0x4
37 #define TPGS_STATE_OFFLINE 0xe
38 #define TPGS_STATE_TRANSITIONING 0xf
40 #define TPGS_SUPPORT_NONE 0x00
41 #define TPGS_SUPPORT_OPTIMIZED 0x01
42 #define TPGS_SUPPORT_NONOPTIMIZED 0x02
43 #define TPGS_SUPPORT_STANDBY 0x04
44 #define TPGS_SUPPORT_UNAVAILABLE 0x08
45 #define TPGS_SUPPORT_LBA_DEPENDENT 0x10
46 #define TPGS_SUPPORT_OFFLINE 0x40
47 #define TPGS_SUPPORT_TRANSITION 0x80
49 #define RTPG_FMT_MASK 0x70
50 #define RTPG_FMT_EXT_HDR 0x10
52 #define TPGS_MODE_UNINITIALIZED -1
53 #define TPGS_MODE_NONE 0x0
54 #define TPGS_MODE_IMPLICIT 0x1
55 #define TPGS_MODE_EXPLICIT 0x2
57 #define ALUA_INQUIRY_SIZE 36
58 #define ALUA_FAILOVER_TIMEOUT 60
59 #define ALUA_FAILOVER_RETRIES 5
61 /* flags passed from user level */
62 #define ALUA_OPTIMIZE_STPG 1
65 struct scsi_dh_data dh_data
;
71 unsigned flags
; /* used for optimizing STPG */
72 unsigned char inq
[ALUA_INQUIRY_SIZE
];
75 unsigned char transition_tmo
;
76 unsigned char sense
[SCSI_SENSE_BUFFERSIZE
];
78 struct scsi_device
*sdev
;
79 activate_complete callback_fn
;
83 #define ALUA_POLICY_SWITCH_CURRENT 0
84 #define ALUA_POLICY_SWITCH_ALL 1
86 static char print_alua_state(int);
87 static int alua_check_sense(struct scsi_device
*, struct scsi_sense_hdr
*);
89 static inline struct alua_dh_data
*get_alua_data(struct scsi_device
*sdev
)
91 return container_of(sdev
->scsi_dh_data
, struct alua_dh_data
, dh_data
);
94 static int realloc_buffer(struct alua_dh_data
*h
, unsigned len
)
96 if (h
->buff
&& h
->buff
!= h
->inq
)
99 h
->buff
= kmalloc(len
, GFP_NOIO
);
102 h
->bufflen
= ALUA_INQUIRY_SIZE
;
109 static struct request
*get_alua_req(struct scsi_device
*sdev
,
110 void *buffer
, unsigned buflen
, int rw
)
113 struct request_queue
*q
= sdev
->request_queue
;
115 rq
= blk_get_request(q
, rw
, GFP_NOIO
);
118 sdev_printk(KERN_INFO
, sdev
,
119 "%s: blk_get_request failed\n", __func__
);
122 blk_rq_set_block_pc(rq
);
124 if (buflen
&& blk_rq_map_kern(q
, rq
, buffer
, buflen
, GFP_NOIO
)) {
126 sdev_printk(KERN_INFO
, sdev
,
127 "%s: blk_rq_map_kern failed\n", __func__
);
131 rq
->cmd_flags
|= REQ_FAILFAST_DEV
| REQ_FAILFAST_TRANSPORT
|
133 rq
->retries
= ALUA_FAILOVER_RETRIES
;
134 rq
->timeout
= ALUA_FAILOVER_TIMEOUT
* HZ
;
140 * submit_vpd_inquiry - Issue an INQUIRY VPD page 0x83 command
141 * @sdev: sdev the command should be sent to
143 static int submit_vpd_inquiry(struct scsi_device
*sdev
, struct alua_dh_data
*h
)
146 int err
= SCSI_DH_RES_TEMP_UNAVAIL
;
148 rq
= get_alua_req(sdev
, h
->buff
, h
->bufflen
, READ
);
152 /* Prepare the command. */
153 rq
->cmd
[0] = INQUIRY
;
156 rq
->cmd
[4] = h
->bufflen
;
157 rq
->cmd_len
= COMMAND_SIZE(INQUIRY
);
159 rq
->sense
= h
->sense
;
160 memset(rq
->sense
, 0, SCSI_SENSE_BUFFERSIZE
);
161 rq
->sense_len
= h
->senselen
= 0;
163 err
= blk_execute_rq(rq
->q
, NULL
, rq
, 1);
165 sdev_printk(KERN_INFO
, sdev
,
166 "%s: evpd inquiry failed with %x\n",
167 ALUA_DH_NAME
, rq
->errors
);
168 h
->senselen
= rq
->sense_len
;
177 * submit_rtpg - Issue a REPORT TARGET GROUP STATES command
178 * @sdev: sdev the command should be sent to
180 static unsigned submit_rtpg(struct scsi_device
*sdev
, struct alua_dh_data
*h
,
181 bool rtpg_ext_hdr_req
)
184 int err
= SCSI_DH_RES_TEMP_UNAVAIL
;
186 rq
= get_alua_req(sdev
, h
->buff
, h
->bufflen
, READ
);
190 /* Prepare the command. */
191 rq
->cmd
[0] = MAINTENANCE_IN
;
192 if (rtpg_ext_hdr_req
)
193 rq
->cmd
[1] = MI_REPORT_TARGET_PGS
| MI_EXT_HDR_PARAM_FMT
;
195 rq
->cmd
[1] = MI_REPORT_TARGET_PGS
;
196 rq
->cmd
[6] = (h
->bufflen
>> 24) & 0xff;
197 rq
->cmd
[7] = (h
->bufflen
>> 16) & 0xff;
198 rq
->cmd
[8] = (h
->bufflen
>> 8) & 0xff;
199 rq
->cmd
[9] = h
->bufflen
& 0xff;
200 rq
->cmd_len
= COMMAND_SIZE(MAINTENANCE_IN
);
202 rq
->sense
= h
->sense
;
203 memset(rq
->sense
, 0, SCSI_SENSE_BUFFERSIZE
);
204 rq
->sense_len
= h
->senselen
= 0;
206 err
= blk_execute_rq(rq
->q
, NULL
, rq
, 1);
208 sdev_printk(KERN_INFO
, sdev
,
209 "%s: rtpg failed with %x\n",
210 ALUA_DH_NAME
, rq
->errors
);
211 h
->senselen
= rq
->sense_len
;
220 * alua_stpg - Evaluate SET TARGET GROUP STATES
221 * @sdev: the device to be evaluated
222 * @state: the new target group state
224 * Send a SET TARGET GROUP STATES command to the device.
225 * We only have to test here if we should resubmit the command;
226 * any other error is assumed as a failure.
228 static void stpg_endio(struct request
*req
, int error
)
230 struct alua_dh_data
*h
= req
->end_io_data
;
231 struct scsi_sense_hdr sense_hdr
;
232 unsigned err
= SCSI_DH_OK
;
234 if (host_byte(req
->errors
) != DID_OK
||
235 msg_byte(req
->errors
) != COMMAND_COMPLETE
) {
240 if (req
->sense_len
> 0) {
241 err
= scsi_normalize_sense(h
->sense
, SCSI_SENSE_BUFFERSIZE
,
247 err
= alua_check_sense(h
->sdev
, &sense_hdr
);
248 if (err
== ADD_TO_MLQUEUE
) {
252 sdev_printk(KERN_INFO
, h
->sdev
,
253 "%s: stpg sense code: %02x/%02x/%02x\n",
254 ALUA_DH_NAME
, sense_hdr
.sense_key
,
255 sense_hdr
.asc
, sense_hdr
.ascq
);
260 if (err
== SCSI_DH_OK
) {
261 h
->state
= TPGS_STATE_OPTIMIZED
;
262 sdev_printk(KERN_INFO
, h
->sdev
,
263 "%s: port group %02x switched to state %c\n",
264 ALUA_DH_NAME
, h
->group_id
,
265 print_alua_state(h
->state
));
268 req
->end_io_data
= NULL
;
269 __blk_put_request(req
->q
, req
);
270 if (h
->callback_fn
) {
271 h
->callback_fn(h
->callback_data
, err
);
272 h
->callback_fn
= h
->callback_data
= NULL
;
278 * submit_stpg - Issue a SET TARGET GROUP STATES command
280 * Currently we're only setting the current target port group state
281 * to 'active/optimized' and let the array firmware figure out
282 * the states of the remaining groups.
284 static unsigned submit_stpg(struct alua_dh_data
*h
)
288 struct scsi_device
*sdev
= h
->sdev
;
290 /* Prepare the data buffer */
291 memset(h
->buff
, 0, stpg_len
);
292 h
->buff
[4] = TPGS_STATE_OPTIMIZED
& 0x0f;
293 h
->buff
[6] = (h
->group_id
>> 8) & 0xff;
294 h
->buff
[7] = h
->group_id
& 0xff;
296 rq
= get_alua_req(sdev
, h
->buff
, stpg_len
, WRITE
);
298 return SCSI_DH_RES_TEMP_UNAVAIL
;
300 /* Prepare the command. */
301 rq
->cmd
[0] = MAINTENANCE_OUT
;
302 rq
->cmd
[1] = MO_SET_TARGET_PGS
;
303 rq
->cmd
[6] = (stpg_len
>> 24) & 0xff;
304 rq
->cmd
[7] = (stpg_len
>> 16) & 0xff;
305 rq
->cmd
[8] = (stpg_len
>> 8) & 0xff;
306 rq
->cmd
[9] = stpg_len
& 0xff;
307 rq
->cmd_len
= COMMAND_SIZE(MAINTENANCE_OUT
);
309 rq
->sense
= h
->sense
;
310 memset(rq
->sense
, 0, SCSI_SENSE_BUFFERSIZE
);
311 rq
->sense_len
= h
->senselen
= 0;
314 blk_execute_rq_nowait(rq
->q
, NULL
, rq
, 1, stpg_endio
);
319 * alua_check_tpgs - Evaluate TPGS setting
320 * @sdev: device to be checked
322 * Examine the TPGS setting of the sdev to find out if ALUA
325 static int alua_check_tpgs(struct scsi_device
*sdev
, struct alua_dh_data
*h
)
327 int err
= SCSI_DH_OK
;
329 h
->tpgs
= scsi_device_tpgs(sdev
);
331 case TPGS_MODE_EXPLICIT
|TPGS_MODE_IMPLICIT
:
332 sdev_printk(KERN_INFO
, sdev
,
333 "%s: supports implicit and explicit TPGS\n",
336 case TPGS_MODE_EXPLICIT
:
337 sdev_printk(KERN_INFO
, sdev
, "%s: supports explicit TPGS\n",
340 case TPGS_MODE_IMPLICIT
:
341 sdev_printk(KERN_INFO
, sdev
, "%s: supports implicit TPGS\n",
345 h
->tpgs
= TPGS_MODE_NONE
;
346 sdev_printk(KERN_INFO
, sdev
, "%s: not supported\n",
348 err
= SCSI_DH_DEV_UNSUPP
;
356 * alua_vpd_inquiry - Evaluate INQUIRY vpd page 0x83
357 * @sdev: device to be checked
359 * Extract the relative target port and the target port group
360 * descriptor from the list of identificators.
362 static int alua_vpd_inquiry(struct scsi_device
*sdev
, struct alua_dh_data
*h
)
369 err
= submit_vpd_inquiry(sdev
, h
);
371 if (err
!= SCSI_DH_OK
)
374 /* Check if vpd page exceeds initial buffer */
375 len
= (h
->buff
[2] << 8) + h
->buff
[3] + 4;
376 if (len
> h
->bufflen
) {
377 /* Resubmit with the correct length */
378 if (realloc_buffer(h
, len
)) {
379 sdev_printk(KERN_WARNING
, sdev
,
380 "%s: kmalloc buffer failed\n",
382 /* Temporary failure, bypass */
383 return SCSI_DH_DEV_TEMP_BUSY
;
389 * Now look for the correct descriptor.
392 while (d
< h
->buff
+ len
) {
393 switch (d
[1] & 0xf) {
395 /* Relative target port */
396 h
->rel_port
= (d
[6] << 8) + d
[7];
399 /* Target port group */
400 h
->group_id
= (d
[6] << 8) + d
[7];
408 if (h
->group_id
== -1) {
410 * Internal error; TPGS supported but required
411 * VPD identification descriptors not present.
412 * Disable ALUA support
414 sdev_printk(KERN_INFO
, sdev
,
415 "%s: No target port descriptors found\n",
417 h
->state
= TPGS_STATE_OPTIMIZED
;
418 h
->tpgs
= TPGS_MODE_NONE
;
419 err
= SCSI_DH_DEV_UNSUPP
;
421 sdev_printk(KERN_INFO
, sdev
,
422 "%s: port group %02x rel port %02x\n",
423 ALUA_DH_NAME
, h
->group_id
, h
->rel_port
);
429 static char print_alua_state(int state
)
432 case TPGS_STATE_OPTIMIZED
:
434 case TPGS_STATE_NONOPTIMIZED
:
436 case TPGS_STATE_STANDBY
:
438 case TPGS_STATE_UNAVAILABLE
:
440 case TPGS_STATE_LBA_DEPENDENT
:
442 case TPGS_STATE_OFFLINE
:
444 case TPGS_STATE_TRANSITIONING
:
451 static int alua_check_sense(struct scsi_device
*sdev
,
452 struct scsi_sense_hdr
*sense_hdr
)
454 switch (sense_hdr
->sense_key
) {
456 if (sense_hdr
->asc
== 0x04 && sense_hdr
->ascq
== 0x0a)
458 * LUN Not Accessible - ALUA state transition
460 return ADD_TO_MLQUEUE
;
461 if (sense_hdr
->asc
== 0x04 && sense_hdr
->ascq
== 0x0b)
463 * LUN Not Accessible -- Target port in standby state
466 if (sense_hdr
->asc
== 0x04 && sense_hdr
->ascq
== 0x0c)
468 * LUN Not Accessible -- Target port in unavailable state
471 if (sense_hdr
->asc
== 0x04 && sense_hdr
->ascq
== 0x12)
473 * LUN Not Ready -- Offline
476 if (sdev
->allow_restart
&&
477 sense_hdr
->asc
== 0x04 && sense_hdr
->ascq
== 0x02)
479 * if the device is not started, we need to wake
480 * the error handler to start the motor
485 if (sense_hdr
->asc
== 0x29 && sense_hdr
->ascq
== 0x00)
487 * Power On, Reset, or Bus Device Reset, just retry.
489 return ADD_TO_MLQUEUE
;
490 if (sense_hdr
->asc
== 0x29 && sense_hdr
->ascq
== 0x04)
492 * Device internal reset
494 return ADD_TO_MLQUEUE
;
495 if (sense_hdr
->asc
== 0x2a && sense_hdr
->ascq
== 0x01)
497 * Mode Parameters Changed
499 return ADD_TO_MLQUEUE
;
500 if (sense_hdr
->asc
== 0x2a && sense_hdr
->ascq
== 0x06)
504 return ADD_TO_MLQUEUE
;
505 if (sense_hdr
->asc
== 0x2a && sense_hdr
->ascq
== 0x07)
507 * Implicit ALUA state transition failed
509 return ADD_TO_MLQUEUE
;
510 if (sense_hdr
->asc
== 0x3f && sense_hdr
->ascq
== 0x03)
512 * Inquiry data has changed
514 return ADD_TO_MLQUEUE
;
515 if (sense_hdr
->asc
== 0x3f && sense_hdr
->ascq
== 0x0e)
517 * REPORTED_LUNS_DATA_HAS_CHANGED is reported
518 * when switching controllers on targets like
519 * Intel Multi-Flex. We can just retry.
521 return ADD_TO_MLQUEUE
;
525 return SCSI_RETURN_NOT_HANDLED
;
529 * alua_rtpg - Evaluate REPORT TARGET GROUP STATES
530 * @sdev: the device to be evaluated.
531 * @wait_for_transition: if nonzero, wait ALUA_FAILOVER_TIMEOUT seconds for device to exit transitioning state
533 * Evaluate the Target Port Group State.
534 * Returns SCSI_DH_DEV_OFFLINED if the path is
535 * found to be unusable.
537 static int alua_rtpg(struct scsi_device
*sdev
, struct alua_dh_data
*h
, int wait_for_transition
)
539 struct scsi_sense_hdr sense_hdr
;
540 int len
, k
, off
, valid_states
= 0;
543 bool rtpg_ext_hdr_req
= 1;
544 unsigned long expiry
, interval
= 0;
545 unsigned int tpg_desc_tbl_off
;
546 unsigned char orig_transition_tmo
;
548 if (!h
->transition_tmo
)
549 expiry
= round_jiffies_up(jiffies
+ ALUA_FAILOVER_TIMEOUT
* HZ
);
551 expiry
= round_jiffies_up(jiffies
+ h
->transition_tmo
* HZ
);
554 err
= submit_rtpg(sdev
, h
, rtpg_ext_hdr_req
);
556 if (err
== SCSI_DH_IO
&& h
->senselen
> 0) {
557 err
= scsi_normalize_sense(h
->sense
, SCSI_SENSE_BUFFERSIZE
,
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 (rtpg_ext_hdr_req
== 1 &&
571 sense_hdr
.sense_key
== ILLEGAL_REQUEST
&&
572 sense_hdr
.asc
== 0x24 && sense_hdr
.ascq
== 0) {
573 rtpg_ext_hdr_req
= 0;
577 err
= alua_check_sense(sdev
, &sense_hdr
);
578 if (err
== ADD_TO_MLQUEUE
&& time_before(jiffies
, expiry
))
580 sdev_printk(KERN_INFO
, sdev
,
581 "%s: rtpg sense code %02x/%02x/%02x\n",
582 ALUA_DH_NAME
, sense_hdr
.sense_key
,
583 sense_hdr
.asc
, sense_hdr
.ascq
);
586 if (err
!= SCSI_DH_OK
)
589 len
= (h
->buff
[0] << 24) + (h
->buff
[1] << 16) +
590 (h
->buff
[2] << 8) + h
->buff
[3] + 4;
592 if (len
> h
->bufflen
) {
593 /* Resubmit with the correct length */
594 if (realloc_buffer(h
, len
)) {
595 sdev_printk(KERN_WARNING
, sdev
,
596 "%s: kmalloc buffer failed\n",__func__
);
597 /* Temporary failure, bypass */
598 return SCSI_DH_DEV_TEMP_BUSY
;
603 orig_transition_tmo
= h
->transition_tmo
;
604 if ((h
->buff
[4] & RTPG_FMT_MASK
) == RTPG_FMT_EXT_HDR
&& h
->buff
[5] != 0)
605 h
->transition_tmo
= h
->buff
[5];
607 h
->transition_tmo
= ALUA_FAILOVER_TIMEOUT
;
609 if (wait_for_transition
&& (orig_transition_tmo
!= h
->transition_tmo
)) {
610 sdev_printk(KERN_INFO
, sdev
,
611 "%s: transition timeout set to %d seconds\n",
612 ALUA_DH_NAME
, h
->transition_tmo
);
613 expiry
= jiffies
+ h
->transition_tmo
* HZ
;
616 if ((h
->buff
[4] & RTPG_FMT_MASK
) == RTPG_FMT_EXT_HDR
)
617 tpg_desc_tbl_off
= 8;
619 tpg_desc_tbl_off
= 4;
621 for (k
= tpg_desc_tbl_off
, ucp
= h
->buff
+ tpg_desc_tbl_off
;
623 k
+= off
, ucp
+= off
) {
625 if (h
->group_id
== (ucp
[2] << 8) + ucp
[3]) {
626 h
->state
= ucp
[0] & 0x0f;
627 h
->pref
= ucp
[0] >> 7;
628 valid_states
= ucp
[1];
630 off
= 8 + (ucp
[7] * 4);
633 sdev_printk(KERN_INFO
, sdev
,
634 "%s: port group %02x state %c %s supports %c%c%c%c%c%c%c\n",
635 ALUA_DH_NAME
, h
->group_id
, print_alua_state(h
->state
),
636 h
->pref
? "preferred" : "non-preferred",
637 valid_states
&TPGS_SUPPORT_TRANSITION
?'T':'t',
638 valid_states
&TPGS_SUPPORT_OFFLINE
?'O':'o',
639 valid_states
&TPGS_SUPPORT_LBA_DEPENDENT
?'L':'l',
640 valid_states
&TPGS_SUPPORT_UNAVAILABLE
?'U':'u',
641 valid_states
&TPGS_SUPPORT_STANDBY
?'S':'s',
642 valid_states
&TPGS_SUPPORT_NONOPTIMIZED
?'N':'n',
643 valid_states
&TPGS_SUPPORT_OPTIMIZED
?'A':'a');
646 case TPGS_STATE_TRANSITIONING
:
647 if (wait_for_transition
) {
648 if (time_before(jiffies
, expiry
)) {
649 /* State transition, retry */
659 /* Transitioning time exceeded, set port to standby */
660 h
->state
= TPGS_STATE_STANDBY
;
662 case TPGS_STATE_OFFLINE
:
664 err
= SCSI_DH_DEV_OFFLINED
;
667 /* Useable path if active */
675 * alua_initialize - Initialize ALUA state
676 * @sdev: the device to be initialized
678 * For the prep_fn to work correctly we have
679 * to initialize the ALUA state for the device.
681 static int alua_initialize(struct scsi_device
*sdev
, struct alua_dh_data
*h
)
685 err
= alua_check_tpgs(sdev
, h
);
686 if (err
!= SCSI_DH_OK
)
689 err
= alua_vpd_inquiry(sdev
, h
);
690 if (err
!= SCSI_DH_OK
)
693 err
= alua_rtpg(sdev
, h
, 0);
694 if (err
!= SCSI_DH_OK
)
701 * alua_set_params - set/unset the optimize flag
702 * @sdev: device on the path to be activated
703 * params - parameters in the following format
704 * "no_of_params\0param1\0param2\0param3\0...\0"
705 * For example, to set the flag pass the following parameters
706 * from multipath.conf
707 * hardware_handler "2 alua 1"
709 static int alua_set_params(struct scsi_device
*sdev
, const char *params
)
711 struct alua_dh_data
*h
= get_alua_data(sdev
);
712 unsigned int optimize
= 0, argc
;
713 const char *p
= params
;
714 int result
= SCSI_DH_OK
;
716 if ((sscanf(params
, "%u", &argc
) != 1) || (argc
!= 1))
721 if ((sscanf(p
, "%u", &optimize
) != 1) || (optimize
> 1))
725 h
->flags
|= ALUA_OPTIMIZE_STPG
;
727 h
->flags
&= ~ALUA_OPTIMIZE_STPG
;
732 static uint optimize_stpg
;
733 module_param(optimize_stpg
, uint
, S_IRUGO
|S_IWUSR
);
734 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.");
737 * alua_activate - activate a path
738 * @sdev: device on the path to be activated
740 * We're currently switching the port group to be activated only and
741 * let the array figure out the rest.
742 * There may be other arrays which require us to switch all port groups
743 * based on a certain policy. But until we actually encounter them it
746 static int alua_activate(struct scsi_device
*sdev
,
747 activate_complete fn
, void *data
)
749 struct alua_dh_data
*h
= get_alua_data(sdev
);
750 int err
= SCSI_DH_OK
;
753 err
= alua_rtpg(sdev
, h
, 1);
754 if (err
!= SCSI_DH_OK
)
758 h
->flags
|= ALUA_OPTIMIZE_STPG
;
760 if (h
->tpgs
& TPGS_MODE_EXPLICIT
) {
762 case TPGS_STATE_NONOPTIMIZED
:
764 if ((h
->flags
& ALUA_OPTIMIZE_STPG
) &&
766 (h
->tpgs
& TPGS_MODE_IMPLICIT
))
769 case TPGS_STATE_STANDBY
:
770 case TPGS_STATE_UNAVAILABLE
:
773 case TPGS_STATE_OFFLINE
:
776 case TPGS_STATE_TRANSITIONING
:
786 h
->callback_data
= data
;
787 err
= submit_stpg(h
);
788 if (err
== SCSI_DH_OK
)
790 h
->callback_fn
= h
->callback_data
= NULL
;
800 * alua_prep_fn - request callback
802 * Fail I/O to all paths not in state
803 * active/optimized or active/non-optimized.
805 static int alua_prep_fn(struct scsi_device
*sdev
, struct request
*req
)
807 struct alua_dh_data
*h
= get_alua_data(sdev
);
808 int ret
= BLKPREP_OK
;
810 if (h
->state
== TPGS_STATE_TRANSITIONING
)
812 else if (h
->state
!= TPGS_STATE_OPTIMIZED
&&
813 h
->state
!= TPGS_STATE_NONOPTIMIZED
&&
814 h
->state
!= TPGS_STATE_LBA_DEPENDENT
) {
816 req
->cmd_flags
|= REQ_QUIET
;
822 static bool alua_match(struct scsi_device
*sdev
)
824 return (scsi_device_tpgs(sdev
) != 0);
828 * alua_bus_attach - Attach device handler
829 * @sdev: device to be attached to
831 static struct scsi_dh_data
*alua_bus_attach(struct scsi_device
*sdev
)
833 struct alua_dh_data
*h
;
836 h
= kzalloc(sizeof(*h
) , GFP_KERNEL
);
838 return ERR_PTR(-ENOMEM
);
839 h
->tpgs
= TPGS_MODE_UNINITIALIZED
;
840 h
->state
= TPGS_STATE_OPTIMIZED
;
844 h
->bufflen
= ALUA_INQUIRY_SIZE
;
847 err
= alua_initialize(sdev
, h
);
848 if (err
!= SCSI_DH_OK
&& err
!= SCSI_DH_DEV_OFFLINED
)
851 sdev_printk(KERN_NOTICE
, sdev
, "%s: Attached\n", ALUA_DH_NAME
);
855 return ERR_PTR(-EINVAL
);
859 * alua_bus_detach - Detach device handler
860 * @sdev: device to be detached from
862 static void alua_bus_detach(struct scsi_device
*sdev
)
864 struct alua_dh_data
*h
= get_alua_data(sdev
);
866 if (h
->buff
&& h
->inq
!= h
->buff
)
871 static struct scsi_device_handler alua_dh
= {
872 .name
= ALUA_DH_NAME
,
873 .module
= THIS_MODULE
,
874 .attach
= alua_bus_attach
,
875 .detach
= alua_bus_detach
,
876 .prep_fn
= alua_prep_fn
,
877 .check_sense
= alua_check_sense
,
878 .activate
= alua_activate
,
879 .set_params
= alua_set_params
,
883 static int __init
alua_init(void)
887 r
= scsi_register_device_handler(&alua_dh
);
889 printk(KERN_ERR
"%s: Failed to register scsi device handler",
894 static void __exit
alua_exit(void)
896 scsi_unregister_device_handler(&alua_dh
);
899 module_init(alua_init
);
900 module_exit(alua_exit
);
902 MODULE_DESCRIPTION("DM Multipath ALUA support");
903 MODULE_AUTHOR("Hannes Reinecke <hare@suse.de>");
904 MODULE_LICENSE("GPL");
905 MODULE_VERSION(ALUA_DH_VER
);