diff mbox

[4/6] cxlflash: Improve EEH recovery time

Message ID 1472848803-65143-1-git-send-email-ukrishn@linux.vnet.ibm.com (mailing list archive)
State Not Applicable
Headers show

Commit Message

Uma Krishnan Sept. 2, 2016, 8:40 p.m. UTC 
From: "Matthew R. Ochs" <mrochs@linux.vnet.ibm.com>

When an EEH occurs during device initialization, the port timeout
logic can cause excessive delays as MMIO reads will fail. Depending
on where they are experienced, these delays can lead to a prolonged
reset, causing an unnecessary triggering of other timeout logic in
the SCSI stack or user applications.

To expedite recovery, the port timeout logic is updated to decay the
timeout at a much faster rate when in the presence of a likely EEH
frozen event.

Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
---
 drivers/scsi/cxlflash/main.c | 4 ++++
 1 file changed, 4 insertions(+)

Comments

Uma Krishnan Sept. 9, 2016, 10:14 p.m. UTC | #1 
On 9/2/2016 3:40 PM, Uma Krishnan wrote:
> From: "Matthew R. Ochs" <mrochs@linux.vnet.ibm.com>
>
> When an EEH occurs during device initialization, the port timeout
> logic can cause excessive delays as MMIO reads will fail. Depending
> on where they are experienced, these delays can lead to a prolonged
> reset, causing an unnecessary triggering of other timeout logic in
> the SCSI stack or user applications.
>
> To expedite recovery, the port timeout logic is updated to decay the
> timeout at a much faster rate when in the presence of a likely EEH
> frozen event.
>
> Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>

Acked-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
diff mbox

Patch

diff --git a/drivers/scsi/cxlflash/main.c b/drivers/scsi/cxlflash/main.c
index 4ef5235..42970a4 100644
--- a/drivers/scsi/cxlflash/main.c
+++ b/drivers/scsi/cxlflash/main.c
@@ -1040,6 +1040,8 @@  static int wait_port_online(__be64 __iomem *fc_regs, u32 delay_us, u32 nretry)
 	do {
 		msleep(delay_us / 1000);
 		status = readq_be(&fc_regs[FC_MTIP_STATUS / 8]);
+		if (status == U64_MAX)
+			nretry /= 2;
 	} while ((status & FC_MTIP_STATUS_MASK) != FC_MTIP_STATUS_ONLINE &&
 		 nretry--);
 
@@ -1071,6 +1073,8 @@  static int wait_port_offline(__be64 __iomem *fc_regs, u32 delay_us, u32 nretry)
 	do {
 		msleep(delay_us / 1000);
 		status = readq_be(&fc_regs[FC_MTIP_STATUS / 8]);
+		if (status == U64_MAX)
+			nretry /= 2;
 	} while ((status & FC_MTIP_STATUS_MASK) != FC_MTIP_STATUS_OFFLINE &&
 		 nretry--);