[PATCH] libata: don't schedule EH on wcache on/off if old EH

Do not schedule EH for revalidation on wcache on/off if old EH.  Old
EH cannot handle it and will result in WARN_ON()'s and oops.

This closes bug #7412.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 7 insertions, 5 deletions

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 5c1fc467fc7f..22643c0d9a56 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -1451,6 +1451,7 @@ nothing_to_do:
 
 static void ata_scsi_qc_complete(struct ata_queued_cmd *qc)
 {
+        struct ata_port *ap = qc->ap;
         struct scsi_cmnd *cmd = qc->scsicmd;
         u8 *cdb = cmd->cmnd;
         int need_sense = (qc->err_mask != 0);
@@ -1459,11 +1460,12 @@ static void ata_scsi_qc_complete(struct ata_queued_cmd *qc)
          * schedule EH_REVALIDATE operation to update the IDENTIFY DEVICE
          * cache
          */
-        if (!need_sense && (qc->tf.command == ATA_CMD_SET_FEATURES) &&
+        if (ap->ops->error_handler &&
+            !need_sense && (qc->tf.command == ATA_CMD_SET_FEATURES) &&
             ((qc->tf.feature == SETFEATURES_WC_ON) ||
              (qc->tf.feature == SETFEATURES_WC_OFF))) {
-                qc->ap->eh_info.action |= ATA_EH_REVALIDATE;
-                ata_port_schedule_eh(qc->ap);
+                ap->eh_info.action |= ATA_EH_REVALIDATE;
+                ata_port_schedule_eh(ap);
         }
 
         /* For ATA pass thru (SAT) commands, generate a sense block if
@@ -1490,8 +1492,8 @@ static void ata_scsi_qc_complete(struct ata_queued_cmd *qc)
                 }
         }
 
-        if (need_sense && !qc->ap->ops->error_handler)
-                ata_dump_status(qc->ap->id, &qc->result_tf);
+        if (need_sense && !ap->ops->error_handler)
+                ata_dump_status(ap->id, &qc->result_tf);
 
         qc->scsidone(cmd);