Commit 9d2c3039 authored by Hannes Reinecke's avatar Hannes Reinecke Committed by Martin K. Petersen

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: default avatarBart Van Assche <>
Reviewed-by: default avatarEwan Milne <>
Reviewed-by: default avatarChristoph Hellwig <>
Signed-off-by: default avatarHannes Reinecke <>
Signed-off-by: default avatarMartin K. Petersen <>
parent c57168a1
......@@ -465,6 +465,30 @@ 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,
if (sense_hdr.sense_key == NOT_READY &&
sense_hdr.asc == 0x04 && sense_hdr.ascq == 0x0a)
else if (retval)
return SCSI_DH_IO;
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 (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);
/* 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) {
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