[ 3.8.y.z extended stable ] Patch "[SCSI] aacraid: Fix for arrays are going offline in the" has been added to staging queue

[Luis Henriques]

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

    [SCSI] aacraid: Fix for arrays are going offline in the

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

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.
-Luis

------

>From b10e3e058cfd2711674eb8516fc8260d507393c3 Mon Sep 17 00:00:00 2001
From: Mahesh Rajashekhara <Mahesh.Rajashekhara at pmcs.com>
Date: Tue, 18 Jun 2013 17:02:07 +0530
Subject: [PATCH] [SCSI] aacraid: Fix for arrays are going offline in the
 system. System hangs

commit c5bebd829dd95602c15f8da8cc50fa938b5e0254 upstream.

One of the customer had reported that the set of raid logical arrays will
become unavailable (I/O offline) after a long hours of IO stress test.  The OS
wouldn`t be accessible afterwards and require a hard reset.

This driver patch has a fix for race condition between the doorbell and the
circular buffer. The driver is modified to do an extra read after clearing the
doorbell in case there had been a completion posted during the small timing
window.

With this fix, we ran IO stress for ~13 days. There were no IO failures.

Signed-off-by: Mahesh Rajashekhara <Mahesh.Rajashekhara at pmcs.com>
Signed-off-by: James Bottomley <JBottomley at Parallels.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/scsi/aacraid/src.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/scsi/aacraid/src.c b/drivers/scsi/aacraid/src.c
index 3b021ec..e34418f 100644
--- a/drivers/scsi/aacraid/src.c
+++ b/drivers/scsi/aacraid/src.c
@@ -93,6 +93,9 @@ static irqreturn_t aac_src_intr_message(int irq, void *dev_id)
 			int send_it = 0;
 			extern int aac_sync_mode;

+			src_writel(dev, MUnit.ODR_C, bellbits);
+			src_readl(dev, MUnit.ODR_C);
+
 			if (!aac_sync_mode) {
 				src_writel(dev, MUnit.ODR_C, bellbits);
 				src_readl(dev, MUnit.ODR_C);
--
1.8.1.2