[for-4.4,3/4] scsi: cxlflash: Improve EEH recovery time

Message ID 1493916720-8819-4-git-send-email-sumit.semwal@linaro.org
State New
Headers show
Series
  • Stable commits from Ubuntu Xenial 4.4-lts
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Commit Message

Sumit Semwal May 4, 2017, 4:51 p.m.
From: "Matthew R. Ochs" <mrochs@linux.vnet.ibm.com>


[ Upstream commit 05dab43230fdc0d14ca885b473a2740fe017ecb1 ]

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>

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>

---
 drivers/scsi/cxlflash/main.c | 4 ++++
 1 file changed, 4 insertions(+)

-- 
2.7.4

Patch

diff --git a/drivers/scsi/cxlflash/main.c b/drivers/scsi/cxlflash/main.c
index d0eed07..0b09673 100644
--- a/drivers/scsi/cxlflash/main.c
+++ b/drivers/scsi/cxlflash/main.c
@@ -996,6 +996,8 @@  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--);
 
@@ -1027,6 +1029,8 @@  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--);