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[PATCH] libata: clear sdev->locked on door lock failure

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SCSI EH locks door if sdev->locked is set.  Sometimes door lock
command fails continuously (e.g. when medium is not present) and as
libata uses EH to acquire sense data, this easily creates a loop where
a failed lock door invokes EH and EH issues lock door on completion.

This patch clears sdev->locked on door lock failure to break this
loop.  This problem has been spotted and diagnosed by Unicorn Chang
<uchang@tw.ibm.com>.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
This commit is contained in:
Tejun Heo 2006-08-08 14:08:59 +09:00 committed by Jeff Garzik
parent 85455dd342
commit 22aac0896b
1 changed files with 13 additions and 0 deletions
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13
drivers/scsi/libata-scsi.c
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@ -2353,6 +2353,19 @@ static void atapi_qc_complete(struct ata_queued_cmd *qc)
ata_gen_ata_desc_sense(qc);
}
/* SCSI EH automatically locks door if sdev->locked is
* set. Sometimes door lock request continues to
* fail, for example, when no media is present. This
* creates a loop - SCSI EH issues door lock which
* fails and gets invoked again to acquire sense data
* for the failed command.
*
* If door lock fails, always clear sdev->locked to
* avoid this infinite loop.
*/
if (qc->cdb[0] == ALLOW_MEDIUM_REMOVAL)
qc->dev->sdev->locked = 0;
qc->scsicmd->result = SAM_STAT_CHECK_CONDITION;
qc->scsidone(cmd);
ata_qc_free(qc);