[3.5.y.z extended stable] Patch "libata: make ata_eh_qc_retry() bump scmd->allowed on bogus failures" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    libata: make ata_eh_qc_retry() bump scmd->allowed on bogus failures

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

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>From 36bf34821502b72db2baaec669cdd0d2410389a0 Mon Sep 17 00:00:00 2001
From: Gwendal Grignou <gwendal at google.com>
Date: Fri, 7 Aug 2009 16:17:49 -0700
Subject: libata: make ata_eh_qc_retry() bump scmd->allowed on bogus failures

commit f13e220161e738c2710b9904dcb3cf8bb0bcce61 upstream.

libata EH decrements scmd->retries when the command failed for reasons
unrelated to the command itself so that, for example, commands aborted
due to suspend / resume cycle don't get penalized; however,
decrementing scmd->retries isn't enough for ATA passthrough commands.

Without this fix, ATA passthrough commands are not resend to the
drive, and no error is signalled to the caller because:

- allowed retry count is 1
- ata_eh_qc_complete fill the sense data, so result is valid
- sense data is filled with untouched ATA registers.

Signed-off-by: Gwendal Grignou <gwendal at google.com>
Signed-off-by: Tejun Heo <tj at kernel.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/ata/libata-eh.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index 85fe5bc..1e2a1dd 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -1287,14 +1287,14 @@ void ata_eh_qc_complete(struct ata_queued_cmd *qc)
  *	should be retried.  To be used from EH.
  *
  *	SCSI midlayer limits the number of retries to scmd->allowed.
- *	scmd->retries is decremented for commands which get retried
+ *	scmd->allowed is incremented for commands which get retried
  *	due to unrelated failures (qc->err_mask is zero).
  */
 void ata_eh_qc_retry(struct ata_queued_cmd *qc)
 {
 	struct scsi_cmnd *scmd = qc->scsicmd;
-	if (!qc->err_mask && scmd->retries)
-		scmd->retries--;
+	if (!qc->err_mask)
+		scmd->allowed++;
 	__ata_eh_qc_complete(qc);
 }

--
1.8.3.2