[PATCH] libata: check if port is disabled after internal command

libata core is being changed to disallow port/device disable on lower
layers.  However, some LLDDs (sata_mv) directly disable port on
command failure.  This patch makes ata_exec_internal() check whether a
port got disabled after an internal command.  If it is, AC_ERR_SYSTEM
is added to err_mask and the port gets re-enabled.

As internal command failure results in device disable for drivers
which don't implement newer reset/EH callbacks, this change results in
no behavior change for single device per port controllers.  For
slave-possible LLDDs which disable port on command failure, (1) such
drivers don't exist currently, (2) issuing command to the other device
of once-disabled port shouldn't result in catastrophe even if such
driver exists.  So, this should be enough as a temporary measure.

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

diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 1063928e3824c6311b231beb6e5ce9ff75e12fe2..9cd9053e78fe0898c8f2277ab14824f5dd0058ab 100644 (file)
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -1009,6 +1009,22 @@ ata_exec_internal(struct ata_port *ap, struct ata_device *dev,
 
        ata_qc_free(qc);
 
+       /* XXX - Some LLDDs (sata_mv) disable port on command failure.
+        * Until those drivers are fixed, we detect the condition
+        * here, fail the command with AC_ERR_SYSTEM and reenable the
+        * port.
+        *
+        * Note that this doesn't change any behavior as internal
+        * command failure results in disabling the device in the
+        * higher layer for LLDDs without new reset/EH callbacks.
+        *
+        * Kill the following code as soon as those drivers are fixed.
+        */
+       if (ap->flags & ATA_FLAG_PORT_DISABLED) {
+               err_mask |= AC_ERR_SYSTEM;
+               ata_port_probe(ap);
+       }
+
        return err_mask;
 }