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
56 #define ALUA_RTPG_RETRY_DELAY 2
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];
85 unsigned flags; /* used for optimizing STPG */
86 unsigned char transition_tmo;
88 unsigned long interval;
89 struct delayed_work rtpg_work;
91 struct list_head rtpg_list;
92 struct scsi_device *rtpg_sdev;
96 struct list_head node;
97 struct alua_port_group __rcu *pg;
100 struct scsi_device *sdev;
102 struct mutex init_mutex;
105 struct alua_queue_data {
106 struct list_head entry;
107 activate_complete callback_fn;
111 #define ALUA_POLICY_SWITCH_CURRENT 0
112 #define ALUA_POLICY_SWITCH_ALL 1
114 static void alua_rtpg_work(struct work_struct *work);
115 static bool alua_rtpg_queue(struct alua_port_group *pg,
116 struct scsi_device *sdev,
117 struct alua_queue_data *qdata, bool force);
118 static void alua_check(struct scsi_device *sdev, bool force);
120 static void release_port_group(struct kref *kref)
122 struct alua_port_group *pg;
124 pg = container_of(kref, struct alua_port_group, kref);
126 flush_delayed_work(&pg->rtpg_work);
127 spin_lock(&port_group_lock);
129 spin_unlock(&port_group_lock);
134 * submit_rtpg - Issue a REPORT TARGET GROUP STATES command
135 * @sdev: sdev the command should be sent to
137 static int submit_rtpg(struct scsi_device *sdev, unsigned char *buff,
138 int bufflen, struct scsi_sense_hdr *sshdr, int flags)
140 u8 cdb[COMMAND_SIZE(MAINTENANCE_IN)];
141 int req_flags = REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
144 /* Prepare the command. */
145 memset(cdb, 0x0, COMMAND_SIZE(MAINTENANCE_IN));
146 cdb[0] = MAINTENANCE_IN;
147 if (!(flags & ALUA_RTPG_EXT_HDR_UNSUPP))
148 cdb[1] = MI_REPORT_TARGET_PGS | MI_EXT_HDR_PARAM_FMT;
150 cdb[1] = MI_REPORT_TARGET_PGS;
151 put_unaligned_be32(bufflen, &cdb[6]);
153 return scsi_execute(sdev, cdb, DMA_FROM_DEVICE, buff, bufflen, NULL,
154 sshdr, ALUA_FAILOVER_TIMEOUT * HZ,
155 ALUA_FAILOVER_RETRIES, req_flags, 0, NULL);
159 * submit_stpg - Issue a SET TARGET PORT GROUP command
161 * Currently we're only setting the current target port group state
162 * to 'active/optimized' and let the array firmware figure out
163 * the states of the remaining groups.
165 static int submit_stpg(struct scsi_device *sdev, int group_id,
166 struct scsi_sense_hdr *sshdr)
168 u8 cdb[COMMAND_SIZE(MAINTENANCE_OUT)];
169 unsigned char stpg_data[8];
171 int req_flags = REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
174 /* Prepare the data buffer */
175 memset(stpg_data, 0, stpg_len);
176 stpg_data[4] = SCSI_ACCESS_STATE_OPTIMAL;
177 put_unaligned_be16(group_id, &stpg_data[6]);
179 /* Prepare the command. */
180 memset(cdb, 0x0, COMMAND_SIZE(MAINTENANCE_OUT));
181 cdb[0] = MAINTENANCE_OUT;
182 cdb[1] = MO_SET_TARGET_PGS;
183 put_unaligned_be32(stpg_len, &cdb[6]);
185 return scsi_execute(sdev, cdb, DMA_TO_DEVICE, stpg_data, stpg_len, NULL,
186 sshdr, ALUA_FAILOVER_TIMEOUT * HZ,
187 ALUA_FAILOVER_RETRIES, req_flags, 0, NULL);
190 static struct alua_port_group *alua_find_get_pg(char *id_str, size_t id_size,
193 struct alua_port_group *pg;
195 if (!id_str || !id_size || !strlen(id_str))
198 list_for_each_entry(pg, &port_group_list, node) {
199 if (pg->group_id != group_id)
201 if (!pg->device_id_len || pg->device_id_len != id_size)
203 if (strncmp(pg->device_id_str, id_str, id_size))
205 if (!kref_get_unless_zero(&pg->kref))
214 * alua_alloc_pg - Allocate a new port_group structure
216 * @h: alua device_handler data
217 * @group_id: port group id
219 * Allocate a new port_group structure for a given
222 static struct alua_port_group *alua_alloc_pg(struct scsi_device *sdev,
223 int group_id, int tpgs)
225 struct alua_port_group *pg, *tmp_pg;
227 pg = kzalloc(sizeof(struct alua_port_group), GFP_KERNEL);
229 return ERR_PTR(-ENOMEM);
231 pg->device_id_len = scsi_vpd_lun_id(sdev, pg->device_id_str,
232 sizeof(pg->device_id_str));
233 if (pg->device_id_len <= 0) {
235 * TPGS supported but no device identification found.
236 * Generate private device identification.
238 sdev_printk(KERN_INFO, sdev,
239 "%s: No device descriptors found\n",
241 pg->device_id_str[0] = '\0';
242 pg->device_id_len = 0;
244 pg->group_id = group_id;
246 pg->state = SCSI_ACCESS_STATE_OPTIMAL;
248 pg->flags |= ALUA_OPTIMIZE_STPG;
249 kref_init(&pg->kref);
250 INIT_DELAYED_WORK(&pg->rtpg_work, alua_rtpg_work);
251 INIT_LIST_HEAD(&pg->rtpg_list);
252 INIT_LIST_HEAD(&pg->node);
253 INIT_LIST_HEAD(&pg->dh_list);
254 spin_lock_init(&pg->lock);
256 spin_lock(&port_group_lock);
257 tmp_pg = alua_find_get_pg(pg->device_id_str, pg->device_id_len,
260 spin_unlock(&port_group_lock);
265 list_add(&pg->node, &port_group_list);
266 spin_unlock(&port_group_lock);
272 * alua_check_tpgs - Evaluate TPGS setting
273 * @sdev: device to be checked
275 * Examine the TPGS setting of the sdev to find out if ALUA
278 static int alua_check_tpgs(struct scsi_device *sdev)
280 int tpgs = TPGS_MODE_NONE;
283 * ALUA support for non-disk devices is fraught with
284 * difficulties, so disable it for now.
286 if (sdev->type != TYPE_DISK) {
287 sdev_printk(KERN_INFO, sdev,
288 "%s: disable for non-disk devices\n",
293 tpgs = scsi_device_tpgs(sdev);
295 case TPGS_MODE_EXPLICIT|TPGS_MODE_IMPLICIT:
296 sdev_printk(KERN_INFO, sdev,
297 "%s: supports implicit and explicit TPGS\n",
300 case TPGS_MODE_EXPLICIT:
301 sdev_printk(KERN_INFO, sdev, "%s: supports explicit TPGS\n",
304 case TPGS_MODE_IMPLICIT:
305 sdev_printk(KERN_INFO, sdev, "%s: supports implicit TPGS\n",
309 sdev_printk(KERN_INFO, sdev, "%s: not supported\n",
313 sdev_printk(KERN_INFO, sdev,
314 "%s: unsupported TPGS setting %d\n",
316 tpgs = TPGS_MODE_NONE;
324 * alua_check_vpd - Evaluate INQUIRY vpd page 0x83
325 * @sdev: device to be checked
327 * Extract the relative target port and the target port group
328 * descriptor from the list of identificators.
330 static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h,
333 int rel_port = -1, group_id;
334 struct alua_port_group *pg, *old_pg = NULL;
335 bool pg_updated = false;
338 group_id = scsi_vpd_tpg_id(sdev, &rel_port);
341 * Internal error; TPGS supported but required
342 * VPD identification descriptors not present.
343 * Disable ALUA support
345 sdev_printk(KERN_INFO, sdev,
346 "%s: No target port descriptors found\n",
348 return SCSI_DH_DEV_UNSUPP;
351 pg = alua_alloc_pg(sdev, group_id, tpgs);
353 if (PTR_ERR(pg) == -ENOMEM)
354 return SCSI_DH_NOMEM;
355 return SCSI_DH_DEV_UNSUPP;
357 if (pg->device_id_len)
358 sdev_printk(KERN_INFO, sdev,
359 "%s: device %s port group %x rel port %x\n",
360 ALUA_DH_NAME, pg->device_id_str,
363 sdev_printk(KERN_INFO, sdev,
364 "%s: port group %x rel port %x\n",
365 ALUA_DH_NAME, group_id, rel_port);
367 /* Check for existing port group references */
368 spin_lock(&h->pg_lock);
369 old_pg = rcu_dereference_protected(h->pg, lockdep_is_held(&h->pg_lock));
371 /* port group has changed. Update to new port group */
373 spin_lock_irqsave(&old_pg->lock, flags);
374 list_del_rcu(&h->node);
375 spin_unlock_irqrestore(&old_pg->lock, flags);
377 rcu_assign_pointer(h->pg, pg);
381 spin_lock_irqsave(&pg->lock, flags);
383 list_add_rcu(&h->node, &pg->dh_list);
384 spin_unlock_irqrestore(&pg->lock, flags);
386 alua_rtpg_queue(rcu_dereference_protected(h->pg,
387 lockdep_is_held(&h->pg_lock)),
389 spin_unlock(&h->pg_lock);
392 kref_put(&old_pg->kref, release_port_group);
397 static char print_alua_state(unsigned char state)
400 case SCSI_ACCESS_STATE_OPTIMAL:
402 case SCSI_ACCESS_STATE_ACTIVE:
404 case SCSI_ACCESS_STATE_STANDBY:
406 case SCSI_ACCESS_STATE_UNAVAILABLE:
408 case SCSI_ACCESS_STATE_LBA:
410 case SCSI_ACCESS_STATE_OFFLINE:
412 case SCSI_ACCESS_STATE_TRANSITIONING:
419 static int alua_check_sense(struct scsi_device *sdev,
420 struct scsi_sense_hdr *sense_hdr)
422 switch (sense_hdr->sense_key) {
424 if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x0a) {
426 * LUN Not Accessible - ALUA state transition
428 alua_check(sdev, false);
433 if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00) {
435 * Power On, Reset, or Bus Device Reset.
436 * Might have obscured a state transition,
437 * so schedule a recheck.
439 alua_check(sdev, true);
440 return ADD_TO_MLQUEUE;
442 if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x04)
444 * Device internal reset
446 return ADD_TO_MLQUEUE;
447 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x01)
449 * Mode Parameters Changed
451 return ADD_TO_MLQUEUE;
452 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x06) {
456 alua_check(sdev, true);
457 return ADD_TO_MLQUEUE;
459 if (sense_hdr->asc == 0x2a && sense_hdr->ascq == 0x07) {
461 * Implicit ALUA state transition failed
463 alua_check(sdev, true);
464 return ADD_TO_MLQUEUE;
466 if (sense_hdr->asc == 0x3f && sense_hdr->ascq == 0x03)
468 * Inquiry data has changed
470 return ADD_TO_MLQUEUE;
471 if (sense_hdr->asc == 0x3f && sense_hdr->ascq == 0x0e)
473 * REPORTED_LUNS_DATA_HAS_CHANGED is reported
474 * when switching controllers on targets like
475 * Intel Multi-Flex. We can just retry.
477 return ADD_TO_MLQUEUE;
481 return SCSI_RETURN_NOT_HANDLED;
485 * alua_tur - Send a TEST UNIT READY
486 * @sdev: device to which the TEST UNIT READY command should be send
488 * Send a TEST UNIT READY to @sdev to figure out the device state
489 * Returns SCSI_DH_RETRY if the sense code is NOT READY/ALUA TRANSITIONING,
490 * SCSI_DH_OK if no error occurred, and SCSI_DH_IO otherwise.
492 static int alua_tur(struct scsi_device *sdev)
494 struct scsi_sense_hdr sense_hdr;
497 retval = scsi_test_unit_ready(sdev, ALUA_FAILOVER_TIMEOUT * HZ,
498 ALUA_FAILOVER_RETRIES, &sense_hdr);
499 if (sense_hdr.sense_key == NOT_READY &&
500 sense_hdr.asc == 0x04 && sense_hdr.ascq == 0x0a)
501 return SCSI_DH_RETRY;
509 * alua_rtpg - Evaluate REPORT TARGET GROUP STATES
510 * @sdev: the device to be evaluated.
512 * Evaluate the Target Port Group State.
513 * Returns SCSI_DH_DEV_OFFLINED if the path is
514 * found to be unusable.
516 static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg)
518 struct scsi_sense_hdr sense_hdr;
519 struct alua_port_group *tmp_pg;
520 int len, k, off, valid_states = 0, bufflen = ALUA_RTPG_SIZE;
521 unsigned char *desc, *buff;
522 unsigned err, retval;
523 unsigned int tpg_desc_tbl_off;
524 unsigned char orig_transition_tmo;
526 bool transitioning_sense = false;
529 unsigned long transition_tmo = ALUA_FAILOVER_TIMEOUT * HZ;
531 if (pg->transition_tmo)
532 transition_tmo = pg->transition_tmo * HZ;
534 pg->expiry = round_jiffies_up(jiffies + transition_tmo);
537 buff = kzalloc(bufflen, GFP_KERNEL);
539 return SCSI_DH_DEV_TEMP_BUSY;
543 retval = submit_rtpg(sdev, buff, bufflen, &sense_hdr, pg->flags);
546 if (!scsi_sense_valid(&sense_hdr)) {
547 sdev_printk(KERN_INFO, sdev,
548 "%s: rtpg failed, result %d\n",
549 ALUA_DH_NAME, retval);
551 if (driver_byte(retval) == DRIVER_ERROR)
552 return SCSI_DH_DEV_TEMP_BUSY;
557 * submit_rtpg() has failed on existing arrays
558 * when requesting extended header info, and
559 * the array doesn't support extended headers,
560 * even though it shouldn't according to T10.
561 * The retry without rtpg_ext_hdr_req set
563 * Note: some arrays return a sense key of ILLEGAL_REQUEST
564 * with ASC 00h if they don't support the extended header.
566 if (!(pg->flags & ALUA_RTPG_EXT_HDR_UNSUPP) &&
567 sense_hdr.sense_key == ILLEGAL_REQUEST) {
568 pg->flags |= ALUA_RTPG_EXT_HDR_UNSUPP;
572 * If the array returns with 'ALUA state transition'
573 * sense code here it cannot return RTPG data during
574 * transition. So set the state to 'transitioning' directly.
576 if (sense_hdr.sense_key == NOT_READY &&
577 sense_hdr.asc == 0x04 && sense_hdr.ascq == 0x0a) {
578 transitioning_sense = true;
582 * Retry on any other UNIT ATTENTION occurred.
584 if (sense_hdr.sense_key == UNIT_ATTENTION)
586 if (err == SCSI_DH_RETRY &&
587 pg->expiry != 0 && time_before(jiffies, pg->expiry)) {
588 sdev_printk(KERN_ERR, sdev, "%s: rtpg retry\n",
590 scsi_print_sense_hdr(sdev, ALUA_DH_NAME, &sense_hdr);
594 sdev_printk(KERN_ERR, sdev, "%s: rtpg failed\n",
596 scsi_print_sense_hdr(sdev, ALUA_DH_NAME, &sense_hdr);
602 len = get_unaligned_be32(&buff[0]) + 4;
605 /* Resubmit with the correct length */
608 buff = kmalloc(bufflen, GFP_KERNEL);
610 sdev_printk(KERN_WARNING, sdev,
611 "%s: kmalloc buffer failed\n",__func__);
612 /* Temporary failure, bypass */
614 return SCSI_DH_DEV_TEMP_BUSY;
619 orig_transition_tmo = pg->transition_tmo;
620 if ((buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR && buff[5] != 0)
621 pg->transition_tmo = buff[5];
623 pg->transition_tmo = ALUA_FAILOVER_TIMEOUT;
625 if (orig_transition_tmo != pg->transition_tmo) {
626 sdev_printk(KERN_INFO, sdev,
627 "%s: transition timeout set to %d seconds\n",
628 ALUA_DH_NAME, pg->transition_tmo);
629 pg->expiry = jiffies + pg->transition_tmo * HZ;
632 if ((buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR)
633 tpg_desc_tbl_off = 8;
635 tpg_desc_tbl_off = 4;
637 for (k = tpg_desc_tbl_off, desc = buff + tpg_desc_tbl_off;
639 k += off, desc += off) {
640 u16 group_id = get_unaligned_be16(&desc[2]);
642 spin_lock_irqsave(&port_group_lock, flags);
643 tmp_pg = alua_find_get_pg(pg->device_id_str, pg->device_id_len,
645 spin_unlock_irqrestore(&port_group_lock, flags);
647 if (spin_trylock_irqsave(&tmp_pg->lock, flags)) {
648 if ((tmp_pg == pg) ||
649 !(tmp_pg->flags & ALUA_PG_RUNNING)) {
650 struct alua_dh_data *h;
652 tmp_pg->state = desc[0] & 0x0f;
653 tmp_pg->pref = desc[0] >> 7;
655 list_for_each_entry_rcu(h,
656 &tmp_pg->dh_list, node) {
659 h->sdev->access_state = desc[0];
664 valid_states = desc[1];
665 spin_unlock_irqrestore(&tmp_pg->lock, flags);
667 kref_put(&tmp_pg->kref, release_port_group);
669 off = 8 + (desc[7] * 4);
673 spin_lock_irqsave(&pg->lock, flags);
674 if (transitioning_sense)
675 pg->state = SCSI_ACCESS_STATE_TRANSITIONING;
677 sdev_printk(KERN_INFO, sdev,
678 "%s: port group %02x state %c %s supports %c%c%c%c%c%c%c\n",
679 ALUA_DH_NAME, pg->group_id, print_alua_state(pg->state),
680 pg->pref ? "preferred" : "non-preferred",
681 valid_states&TPGS_SUPPORT_TRANSITION?'T':'t',
682 valid_states&TPGS_SUPPORT_OFFLINE?'O':'o',
683 valid_states&TPGS_SUPPORT_LBA_DEPENDENT?'L':'l',
684 valid_states&TPGS_SUPPORT_UNAVAILABLE?'U':'u',
685 valid_states&TPGS_SUPPORT_STANDBY?'S':'s',
686 valid_states&TPGS_SUPPORT_NONOPTIMIZED?'N':'n',
687 valid_states&TPGS_SUPPORT_OPTIMIZED?'A':'a');
690 case SCSI_ACCESS_STATE_TRANSITIONING:
691 if (time_before(jiffies, pg->expiry)) {
692 /* State transition, retry */
693 pg->interval = ALUA_RTPG_RETRY_DELAY;
696 struct alua_dh_data *h;
698 /* Transitioning time exceeded, set port to standby */
700 pg->state = SCSI_ACCESS_STATE_STANDBY;
703 list_for_each_entry_rcu(h, &pg->dh_list, node) {
706 h->sdev->access_state =
707 (pg->state & SCSI_ACCESS_STATE_MASK);
709 h->sdev->access_state |=
710 SCSI_ACCESS_STATE_PREFERRED;
715 case SCSI_ACCESS_STATE_OFFLINE:
717 err = SCSI_DH_DEV_OFFLINED;
721 /* Useable path if active */
726 spin_unlock_irqrestore(&pg->lock, flags);
732 * alua_stpg - Issue a SET TARGET PORT GROUP command
734 * Issue a SET TARGET PORT GROUP command and evaluate the
735 * response. Returns SCSI_DH_RETRY per default to trigger
736 * a re-evaluation of the target group state or SCSI_DH_OK
737 * if no further action needs to be taken.
739 static unsigned alua_stpg(struct scsi_device *sdev, struct alua_port_group *pg)
742 struct scsi_sense_hdr sense_hdr;
744 if (!(pg->tpgs & TPGS_MODE_EXPLICIT)) {
745 /* Only implicit ALUA supported, retry */
746 return SCSI_DH_RETRY;
749 case SCSI_ACCESS_STATE_OPTIMAL:
751 case SCSI_ACCESS_STATE_ACTIVE:
752 if ((pg->flags & ALUA_OPTIMIZE_STPG) &&
754 (pg->tpgs & TPGS_MODE_IMPLICIT))
757 case SCSI_ACCESS_STATE_STANDBY:
758 case SCSI_ACCESS_STATE_UNAVAILABLE:
760 case SCSI_ACCESS_STATE_OFFLINE:
762 case SCSI_ACCESS_STATE_TRANSITIONING:
765 sdev_printk(KERN_INFO, sdev,
766 "%s: stpg failed, unhandled TPGS state %d",
767 ALUA_DH_NAME, pg->state);
768 return SCSI_DH_NOSYS;
770 retval = submit_stpg(sdev, pg->group_id, &sense_hdr);
773 if (!scsi_sense_valid(&sense_hdr)) {
774 sdev_printk(KERN_INFO, sdev,
775 "%s: stpg failed, result %d",
776 ALUA_DH_NAME, retval);
777 if (driver_byte(retval) == DRIVER_ERROR)
778 return SCSI_DH_DEV_TEMP_BUSY;
780 sdev_printk(KERN_INFO, sdev, "%s: stpg failed\n",
782 scsi_print_sense_hdr(sdev, ALUA_DH_NAME, &sense_hdr);
786 return SCSI_DH_RETRY;
789 static void alua_rtpg_work(struct work_struct *work)
791 struct alua_port_group *pg =
792 container_of(work, struct alua_port_group, rtpg_work.work);
793 struct scsi_device *sdev;
794 LIST_HEAD(qdata_list);
795 int err = SCSI_DH_OK;
796 struct alua_queue_data *qdata, *tmp;
799 spin_lock_irqsave(&pg->lock, flags);
800 sdev = pg->rtpg_sdev;
802 WARN_ON(pg->flags & ALUA_PG_RUN_RTPG);
803 WARN_ON(pg->flags & ALUA_PG_RUN_STPG);
804 spin_unlock_irqrestore(&pg->lock, flags);
805 kref_put(&pg->kref, release_port_group);
808 pg->flags |= ALUA_PG_RUNNING;
809 if (pg->flags & ALUA_PG_RUN_RTPG) {
810 int state = pg->state;
812 pg->flags &= ~ALUA_PG_RUN_RTPG;
813 spin_unlock_irqrestore(&pg->lock, flags);
814 if (state == SCSI_ACCESS_STATE_TRANSITIONING) {
815 if (alua_tur(sdev) == SCSI_DH_RETRY) {
816 spin_lock_irqsave(&pg->lock, flags);
817 pg->flags &= ~ALUA_PG_RUNNING;
818 pg->flags |= ALUA_PG_RUN_RTPG;
820 pg->interval = ALUA_RTPG_RETRY_DELAY;
821 spin_unlock_irqrestore(&pg->lock, flags);
822 queue_delayed_work(kaluad_wq, &pg->rtpg_work,
826 /* Send RTPG on failure or if TUR indicates SUCCESS */
828 err = alua_rtpg(sdev, pg);
829 spin_lock_irqsave(&pg->lock, flags);
830 if (err == SCSI_DH_RETRY || pg->flags & ALUA_PG_RUN_RTPG) {
831 pg->flags &= ~ALUA_PG_RUNNING;
832 if (!pg->interval && !(pg->flags & ALUA_PG_RUN_RTPG))
833 pg->interval = ALUA_RTPG_RETRY_DELAY;
834 pg->flags |= ALUA_PG_RUN_RTPG;
835 spin_unlock_irqrestore(&pg->lock, flags);
836 queue_delayed_work(kaluad_wq, &pg->rtpg_work,
840 if (err != SCSI_DH_OK)
841 pg->flags &= ~ALUA_PG_RUN_STPG;
843 if (pg->flags & ALUA_PG_RUN_STPG) {
844 pg->flags &= ~ALUA_PG_RUN_STPG;
845 spin_unlock_irqrestore(&pg->lock, flags);
846 err = alua_stpg(sdev, pg);
847 spin_lock_irqsave(&pg->lock, flags);
848 if (err == SCSI_DH_RETRY || pg->flags & ALUA_PG_RUN_RTPG) {
849 pg->flags |= ALUA_PG_RUN_RTPG;
851 pg->flags &= ~ALUA_PG_RUNNING;
852 spin_unlock_irqrestore(&pg->lock, flags);
853 queue_delayed_work(kaluad_wq, &pg->rtpg_work,
859 list_splice_init(&pg->rtpg_list, &qdata_list);
860 pg->rtpg_sdev = NULL;
861 spin_unlock_irqrestore(&pg->lock, flags);
863 list_for_each_entry_safe(qdata, tmp, &qdata_list, entry) {
864 list_del(&qdata->entry);
865 if (qdata->callback_fn)
866 qdata->callback_fn(qdata->callback_data, err);
869 spin_lock_irqsave(&pg->lock, flags);
870 pg->flags &= ~ALUA_PG_RUNNING;
871 spin_unlock_irqrestore(&pg->lock, flags);
872 scsi_device_put(sdev);
873 kref_put(&pg->kref, release_port_group);
877 * alua_rtpg_queue() - cause RTPG to be submitted asynchronously
879 * Returns true if and only if alua_rtpg_work() will be called asynchronously.
880 * That function is responsible for calling @qdata->fn().
882 static bool alua_rtpg_queue(struct alua_port_group *pg,
883 struct scsi_device *sdev,
884 struct alua_queue_data *qdata, bool force)
888 if (WARN_ON_ONCE(!pg) || scsi_device_get(sdev))
891 spin_lock_irqsave(&pg->lock, flags);
893 list_add_tail(&qdata->entry, &pg->rtpg_list);
894 pg->flags |= ALUA_PG_RUN_STPG;
897 if (pg->rtpg_sdev == NULL) {
899 pg->flags |= ALUA_PG_RUN_RTPG;
901 pg->rtpg_sdev = sdev;
903 } else if (!(pg->flags & ALUA_PG_RUN_RTPG) && force) {
904 pg->flags |= ALUA_PG_RUN_RTPG;
905 /* Do not queue if the worker is already running */
906 if (!(pg->flags & ALUA_PG_RUNNING)) {
912 spin_unlock_irqrestore(&pg->lock, flags);
915 if (queue_delayed_work(kaluad_wq, &pg->rtpg_work,
916 msecs_to_jiffies(ALUA_RTPG_DELAY_MSECS)))
919 kref_put(&pg->kref, release_port_group);
922 scsi_device_put(sdev);
928 * alua_initialize - Initialize ALUA state
929 * @sdev: the device to be initialized
931 * For the prep_fn to work correctly we have
932 * to initialize the ALUA state for the device.
934 static int alua_initialize(struct scsi_device *sdev, struct alua_dh_data *h)
936 int err = SCSI_DH_DEV_UNSUPP, tpgs;
938 mutex_lock(&h->init_mutex);
939 tpgs = alua_check_tpgs(sdev);
940 if (tpgs != TPGS_MODE_NONE)
941 err = alua_check_vpd(sdev, h, tpgs);
943 mutex_unlock(&h->init_mutex);
947 * alua_set_params - set/unset the optimize flag
948 * @sdev: device on the path to be activated
949 * params - parameters in the following format
950 * "no_of_params\0param1\0param2\0param3\0...\0"
951 * For example, to set the flag pass the following parameters
952 * from multipath.conf
953 * hardware_handler "2 alua 1"
955 static int alua_set_params(struct scsi_device *sdev, const char *params)
957 struct alua_dh_data *h = sdev->handler_data;
958 struct alua_port_group *pg = NULL;
959 unsigned int optimize = 0, argc;
960 const char *p = params;
961 int result = SCSI_DH_OK;
964 if ((sscanf(params, "%u", &argc) != 1) || (argc != 1))
969 if ((sscanf(p, "%u", &optimize) != 1) || (optimize > 1))
973 pg = rcu_dereference(h->pg);
978 spin_lock_irqsave(&pg->lock, flags);
980 pg->flags |= ALUA_OPTIMIZE_STPG;
982 pg->flags &= ~ALUA_OPTIMIZE_STPG;
983 spin_unlock_irqrestore(&pg->lock, flags);
990 * alua_activate - activate a path
991 * @sdev: device on the path to be activated
993 * We're currently switching the port group to be activated only and
994 * let the array figure out the rest.
995 * There may be other arrays which require us to switch all port groups
996 * based on a certain policy. But until we actually encounter them it
999 static int alua_activate(struct scsi_device *sdev,
1000 activate_complete fn, void *data)
1002 struct alua_dh_data *h = sdev->handler_data;
1003 int err = SCSI_DH_OK;
1004 struct alua_queue_data *qdata;
1005 struct alua_port_group *pg;
1007 qdata = kzalloc(sizeof(*qdata), GFP_KERNEL);
1009 err = SCSI_DH_RES_TEMP_UNAVAIL;
1012 qdata->callback_fn = fn;
1013 qdata->callback_data = data;
1015 mutex_lock(&h->init_mutex);
1017 pg = rcu_dereference(h->pg);
1018 if (!pg || !kref_get_unless_zero(&pg->kref)) {
1021 err = h->init_error;
1022 mutex_unlock(&h->init_mutex);
1026 mutex_unlock(&h->init_mutex);
1028 if (alua_rtpg_queue(pg, sdev, qdata, true))
1031 err = SCSI_DH_DEV_OFFLINED;
1032 kref_put(&pg->kref, release_port_group);
1040 * alua_check - check path status
1041 * @sdev: device on the path to be checked
1043 * Check the device status
1045 static void alua_check(struct scsi_device *sdev, bool force)
1047 struct alua_dh_data *h = sdev->handler_data;
1048 struct alua_port_group *pg;
1051 pg = rcu_dereference(h->pg);
1052 if (!pg || !kref_get_unless_zero(&pg->kref)) {
1058 alua_rtpg_queue(pg, sdev, NULL, force);
1059 kref_put(&pg->kref, release_port_group);
1063 * alua_prep_fn - request callback
1065 * Fail I/O to all paths not in state
1066 * active/optimized or active/non-optimized.
1068 static int alua_prep_fn(struct scsi_device *sdev, struct request *req)
1070 struct alua_dh_data *h = sdev->handler_data;
1071 struct alua_port_group *pg;
1072 unsigned char state = SCSI_ACCESS_STATE_OPTIMAL;
1073 int ret = BLKPREP_OK;
1076 pg = rcu_dereference(h->pg);
1080 if (state == SCSI_ACCESS_STATE_TRANSITIONING)
1081 ret = BLKPREP_DEFER;
1082 else if (state != SCSI_ACCESS_STATE_OPTIMAL &&
1083 state != SCSI_ACCESS_STATE_ACTIVE &&
1084 state != SCSI_ACCESS_STATE_LBA) {
1086 req->rq_flags |= RQF_QUIET;
1092 static void alua_rescan(struct scsi_device *sdev)
1094 struct alua_dh_data *h = sdev->handler_data;
1096 alua_initialize(sdev, h);
1100 * alua_bus_attach - Attach device handler
1101 * @sdev: device to be attached to
1103 static int alua_bus_attach(struct scsi_device *sdev)
1105 struct alua_dh_data *h;
1106 int err, ret = -EINVAL;
1108 h = kzalloc(sizeof(*h) , GFP_KERNEL);
1111 spin_lock_init(&h->pg_lock);
1112 rcu_assign_pointer(h->pg, NULL);
1113 h->init_error = SCSI_DH_OK;
1115 INIT_LIST_HEAD(&h->node);
1117 mutex_init(&h->init_mutex);
1118 err = alua_initialize(sdev, h);
1119 if (err == SCSI_DH_NOMEM)
1121 if (err != SCSI_DH_OK && err != SCSI_DH_DEV_OFFLINED)
1124 sdev->handler_data = h;
1132 * alua_bus_detach - Detach device handler
1133 * @sdev: device to be detached from
1135 static void alua_bus_detach(struct scsi_device *sdev)
1137 struct alua_dh_data *h = sdev->handler_data;
1138 struct alua_port_group *pg;
1140 spin_lock(&h->pg_lock);
1141 pg = rcu_dereference_protected(h->pg, lockdep_is_held(&h->pg_lock));
1142 rcu_assign_pointer(h->pg, NULL);
1143 spin_unlock(&h->pg_lock);
1145 spin_lock_irq(&pg->lock);
1146 list_del_rcu(&h->node);
1147 spin_unlock_irq(&pg->lock);
1148 kref_put(&pg->kref, release_port_group);
1150 sdev->handler_data = NULL;
1155 static struct scsi_device_handler alua_dh = {
1156 .name = ALUA_DH_NAME,
1157 .module = THIS_MODULE,
1158 .attach = alua_bus_attach,
1159 .detach = alua_bus_detach,
1160 .prep_fn = alua_prep_fn,
1161 .check_sense = alua_check_sense,
1162 .activate = alua_activate,
1163 .rescan = alua_rescan,
1164 .set_params = alua_set_params,
1167 static int __init alua_init(void)
1171 kaluad_wq = alloc_workqueue("kaluad", WQ_MEM_RECLAIM, 0);
1175 r = scsi_register_device_handler(&alua_dh);
1177 printk(KERN_ERR "%s: Failed to register scsi device handler",
1179 destroy_workqueue(kaluad_wq);
1184 static void __exit alua_exit(void)
1186 scsi_unregister_device_handler(&alua_dh);
1187 destroy_workqueue(kaluad_wq);
1190 module_init(alua_init);
1191 module_exit(alua_exit);
1193 MODULE_DESCRIPTION("DM Multipath ALUA support");
1194 MODULE_AUTHOR("Hannes Reinecke <hare@suse.de>");
1195 MODULE_LICENSE("GPL");
1196 MODULE_VERSION(ALUA_DH_VER);