[SCSI] aacraid: Fix for arrays are going offline in the system. System hangs
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@pmcs.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
diff --git a/drivers/scsi/aacraid/src.c b/drivers/scsi/aacraid/src.c
index 0f56d8d..7e17107 100644
--- a/drivers/scsi/aacraid/src.c
+++ b/drivers/scsi/aacraid/src.c
@@ -93,6 +93,9 @@
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);