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[SCSI] scsi_dh_alua: implement 'implied transition timeout'

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During alua transitions, an array can return transitioning
status in response to rtpg requests.  These requests get
retried for a maximum of 60 seconds by default before timing
out.  Sometimes this timeout isn't sufficient to allow the
array to complete the transition.  T10-spc4 addresses this
under 'Report Target Port Groups' command.

This update retrieves the timeout value from the storage
array if available and retries the transitioning rtpgs
for up to the 'implied transitioning timeout' value

Signed-off-by: Rob Evers <revers@redhat.com>
Reviewed-by: Babu Moger <babu.moger@netapp.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This commit is contained in:
Rob Evers 2012-05-18 14:08:54 -04:00 committed by James Bottomley
parent 6ad819b06d
commit 3588c5a21a
2 changed files with 38 additions and 5 deletions
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41
drivers/scsi/device_handler/scsi_dh_alua.c
View file

@ -46,13 +46,16 @@
#define TPGS_SUPPORT_OFFLINE 0x40
#define TPGS_SUPPORT_TRANSITION 0x80
#define RTPG_FMT_MASK 0x70
#define RTPG_FMT_EXT_HDR 0x10
#define TPGS_MODE_UNINITIALIZED -1
#define TPGS_MODE_NONE 0x0
#define TPGS_MODE_IMPLICIT 0x1
#define TPGS_MODE_EXPLICIT 0x2
#define ALUA_INQUIRY_SIZE 36
#define ALUA_FAILOVER_TIMEOUT (60 * HZ)
#define ALUA_FAILOVER_TIMEOUT 60
#define ALUA_FAILOVER_RETRIES 5
/* flags passed from user level */
@ -68,6 +71,7 @@ struct alua_dh_data {
unsigned char inq[ALUA_INQUIRY_SIZE];
unsigned char *buff;
int bufflen;
unsigned char transition_tmo;
unsigned char sense[SCSI_SENSE_BUFFERSIZE];
int senselen;
struct scsi_device *sdev;
@ -128,7 +132,7 @@ static struct request *get_alua_req(struct scsi_device *sdev,
rq->cmd_flags |= REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
REQ_FAILFAST_DRIVER;
rq->retries = ALUA_FAILOVER_RETRIES;
rq->timeout = ALUA_FAILOVER_TIMEOUT;
rq->timeout = ALUA_FAILOVER_TIMEOUT * HZ;
return rq;
}
@ -185,7 +189,7 @@ static unsigned submit_rtpg(struct scsi_device *sdev, struct alua_dh_data *h)
/* Prepare the command. */
rq->cmd[0] = MAINTENANCE_IN;
rq->cmd[1] = MI_REPORT_TARGET_PGS;
rq->cmd[1] = MI_REPORT_TARGET_PGS | MI_EXT_HDR_PARAM_FMT;
rq->cmd[6] = (h->bufflen >> 24) & 0xff;
rq->cmd[7] = (h->bufflen >> 16) & 0xff;
rq->cmd[8] = (h->bufflen >> 8) & 0xff;
@ -519,8 +523,14 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h)
unsigned char *ucp;
unsigned err;
unsigned long expiry, interval = 1000;
unsigned int tpg_desc_tbl_off;
unsigned char orig_transition_tmo;
if (!h->transition_tmo)
expiry = round_jiffies_up(jiffies + ALUA_FAILOVER_TIMEOUT * HZ);
else
expiry = round_jiffies_up(jiffies + h->transition_tmo * HZ);
expiry = round_jiffies_up(jiffies + ALUA_FAILOVER_TIMEOUT);
retry:
err = submit_rtpg(sdev, h);
@ -556,7 +566,28 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_dh_data *h)
goto retry;
}
for (k = 4, ucp = h->buff + 4; k < len; k += off, ucp += off) {
orig_transition_tmo = h->transition_tmo;
if ((h->buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR && h->buff[5] != 0)
h->transition_tmo = h->buff[5];
else
h->transition_tmo = ALUA_FAILOVER_TIMEOUT;
if (orig_transition_tmo != h->transition_tmo) {
sdev_printk(KERN_INFO, sdev,
"%s: transition timeout set to %d seconds\n",
ALUA_DH_NAME, h->transition_tmo);
expiry = jiffies + h->transition_tmo * HZ;
}
if ((h->buff[4] & RTPG_FMT_MASK) == RTPG_FMT_EXT_HDR)
tpg_desc_tbl_off = 8;
else
tpg_desc_tbl_off = 4;
for (k = tpg_desc_tbl_off, ucp = h->buff + tpg_desc_tbl_off;
k < len;
k += off, ucp += off) {
if (h->group_id == (ucp[2] << 8) + ucp[3]) {
h->state = ucp[0] & 0x0f;
h->pref = ucp[0] >> 7;

2
include/scsi/scsi.h
View file

@ -161,6 +161,8 @@ struct scsi_cmnd;
#define MI_REPORT_PRIORITY 0x0e
#define MI_REPORT_TIMESTAMP 0x0f
#define MI_MANAGEMENT_PROTOCOL_IN 0x10
/* value for MI_REPORT_TARGET_PGS ext header */
#define MI_EXT_HDR_PARAM_FMT 0x20
/* values for maintenance out */
#define MO_SET_IDENTIFYING_INFORMATION 0x06
#define MO_SET_TARGET_PGS 0x0a