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@xxxxxxxxxx>. Signed-off-by: Tejun Heo <htejun@xxxxxxxxx> diff --git a/drivers/scsi/libata-scsi.c b/drivers/scsi/libata-scsi.c index 1638e57..f6ddfe6 100644 --- a/drivers/scsi/libata-scsi.c +++ b/drivers/scsi/libata-scsi.c @@ -2353,6 +2353,19 @@ static void atapi_qc_complete(struct ata 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); - : send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
