sym53c8xx_2: Set DID_REQUEUE return code when aborting squeue

This patch fixes I/O errors with the sym53c8xx_2 driver when the disk
returns QUEUE FULL status.

When the controller encounters an error (including QUEUE FULL or BUSY
status), it aborts all not yet submitted requests in the function
sym_dequeue_from_squeue.

This function aborts them with DID_SOFT_ERROR.

If the disk has full tag queue, the request that caused the overflow is
aborted with QUEUE FULL status (and the scsi midlayer properly retries
it until it is accepted by the disk), but the sym53c8xx_2 driver aborts
the following requests with DID_SOFT_ERROR --- for them, the midlayer
does just a few retries and then signals the error up to sd.

The result is that disk returning QUEUE FULL causes request failures.

The error was reproduced on 53c895 with COMPAQ BD03685A24 disk
(rebranded ST336607LC) with command queue 48 or 64 tags.  The disk has
64 tags, but under some access patterns it return QUEUE FULL when there
are less than 64 pending tags.  The SCSI specification allows returning
QUEUE FULL anytime and it is up to the host to retry.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: James Bottomley <JBottomley@Parallels.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/scsi/sym53c8xx_2/sym_hipd.c b/drivers/scsi/sym53c8xx_2/sym_hipd.c
index d92fe40..6b349e3 100644 (file)
--- a/drivers/scsi/sym53c8xx_2/sym_hipd.c
+++ b/drivers/scsi/sym53c8xx_2/sym_hipd.c
@@ -3000,7 +3000,11 @@ sym_dequeue_from_squeue(struct sym_hcb *np, int i, int target, int lun, int task
                if ((target == -1 || cp->target == target) &&
                    (lun    == -1 || cp->lun    == lun)    &&
                    (task   == -1 || cp->tag    == task)) {
+#ifdef SYM_OPT_HANDLE_DEVICE_QUEUEING
                        sym_set_cam_status(cp->cmd, DID_SOFT_ERROR);
+#else
+                       sym_set_cam_status(cp->cmd, DID_REQUEUE);
+#endif
                        sym_remque(&cp->link_ccbq);
                        sym_insque_tail(&cp->link_ccbq, &np->comp_ccbq);
                }