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authorRob Evers <revers@redhat.com>2012-05-18 14:08:54 -0400
committerJames Bottomley <JBottomley@Parallels.com>2012-07-20 08:58:32 +0100
commit3588c5a21aef8c8dcc3b30d72c62971e97af1322 (patch)
treee988d106664bb37c8044165ce18319b65c249e38 /drivers/scsi/device_handler
parent6ad819b06ddf13a5a1d995eb26555903f6c3b71a (diff)
[SCSI] scsi_dh_alua: implement 'implied transition timeout'
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>
Diffstat (limited to 'drivers/scsi/device_handler')
-rw-r--r--drivers/scsi/device_handler/scsi_dh_alua.c41
1 files changed, 36 insertions, 5 deletions
diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index fda9cdea0e6..ac6fddf99e9 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -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;