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| author | Hannes Reinecke <hare@suse.de> | 2016-02-19 11:17:15 +0300 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2016-02-24 05:27:02 +0300 |
| commit | 9d2c30395213166e0b5614fe97576a789864e5de (patch) | |
| tree | 1c7ac2db35b08e00a766478eb76dcd1293a191f0 /drivers/scsi/device_handler | |
| parent | c57168a1e15007e59fd2730678c7a6b28e8c7a37 (diff) | |
| download | linux-9d2c30395213166e0b5614fe97576a789864e5de.tar.xz | |
scsi_dh_alua: Send TEST UNIT READY to poll for transitioning
Sending a 'REPORT TARGET PORT GROUP' command is a costly operation,
as the array has to gather information about all ports.
So instead of using RTPG to poll for a status update when a port
is in transitioning we should be sending a TEST UNIT READY, and
wait for the sense code to report success.
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Ewan Milne <emilne@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/scsi/device_handler')
| -rw-r--r-- | drivers/scsi/device_handler/scsi_dh_alua.c | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c index 98d87d9765ab..3d8a254607e1 100644 --- a/drivers/scsi/device_handler/scsi_dh_alua.c +++ b/drivers/scsi/device_handler/scsi_dh_alua.c @@ -466,6 +466,30 @@ static int alua_check_sense(struct scsi_device *sdev, } /* + * alua_tur - Send a TEST UNIT READY + * @sdev: device to which the TEST UNIT READY command should be send + * + * Send a TEST UNIT READY to @sdev to figure out the device state + * Returns SCSI_DH_RETRY if the sense code is NOT READY/ALUA TRANSITIONING, + * SCSI_DH_OK if no error occurred, and SCSI_DH_IO otherwise. + */ +static int alua_tur(struct scsi_device *sdev) +{ + struct scsi_sense_hdr sense_hdr; + int retval; + + retval = scsi_test_unit_ready(sdev, ALUA_FAILOVER_TIMEOUT * HZ, + ALUA_FAILOVER_RETRIES, &sense_hdr); + if (sense_hdr.sense_key == NOT_READY && + sense_hdr.asc == 0x04 && sense_hdr.ascq == 0x0a) + return SCSI_DH_RETRY; + else if (retval) + return SCSI_DH_IO; + else + return SCSI_DH_OK; +} + +/* * alua_rtpg - Evaluate REPORT TARGET GROUP STATES * @sdev: the device to be evaluated. * @@ -732,8 +756,22 @@ static void alua_rtpg_work(struct work_struct *work) alua_wq = kaluad_sync_wq; pg->flags |= ALUA_PG_RUNNING; if (pg->flags & ALUA_PG_RUN_RTPG) { + int state = pg->state; + pg->flags &= ~ALUA_PG_RUN_RTPG; spin_unlock_irqrestore(&pg->lock, flags); + if (state == TPGS_STATE_TRANSITIONING) { + if (alua_tur(sdev) == SCSI_DH_RETRY) { + spin_lock_irqsave(&pg->lock, flags); + pg->flags &= ~ALUA_PG_RUNNING; + pg->flags |= ALUA_PG_RUN_RTPG; + spin_unlock_irqrestore(&pg->lock, flags); + queue_delayed_work(alua_wq, &pg->rtpg_work, + pg->interval * HZ); + return; + } + /* Send RTPG on failure or if TUR indicates SUCCESS */ + } err = alua_rtpg(sdev, pg); spin_lock_irqsave(&pg->lock, flags); if (err == SCSI_DH_RETRY || pg->flags & ALUA_PG_RUN_RTPG) { |