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

[Luis Henriques]

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

    aacraid: Fix for arrays are going offline in the system.

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

------

>From 33081211eaf57e9d043c33df10af9bd6de9b309f 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] 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>
[ luis: backported to 3.5: adjusted context ]
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 7628206..4de2612 100644
--- a/drivers/scsi/aacraid/src.c
+++ b/drivers/scsi/aacraid/src.c
@@ -101,6 +101,9 @@ static irqreturn_t aac_src_intr_message(int irq, void *dev_id)
 			struct list_head *entry;
 			int send_it = 0;

+			src_writel(dev, MUnit.ODR_C, bellbits);
+			src_readl(dev, MUnit.ODR_C);
+
 			if (dev->sync_fib) {
 				our_interrupt = 1;
 				if (dev->sync_fib->callback)
--
1.8.1.2