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

[Kamal Mostafa]

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-3.8.y-queue branch of the 3.8.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-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.13.

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

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

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>From df318b1b5860933aa78bd7b4aaca239dd8973647 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: Kamal Mostafa <kamal 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 bcf4437..005e458 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -1322,14 +1322,14 @@ 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);
 }

--
1.8.1.2