[PATCH 4/6] cxlflash: Improve EEH recovery time

[Uma Krishnan <ukrishn@linux.vnet.ibm.com>]

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(+)

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--);
 
-- 
2.1.0