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[PATCH 4.4 10/20] scsi: cxlflash: Improve EEH recovery time

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4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>

commit 05dab43230fdc0d14ca885b473a2740fe017ecb1 upstream.

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>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

--- a/drivers/scsi/cxlflash/main.c
+++ b/drivers/scsi/cxlflash/main.c
@@ -996,6 +996,8 @@ static int wait_port_online(__be64 __iom
 	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 __io
 	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--);
 

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[PATCH 4.4 00/20] 4.4.67-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-05-05 20:40 +0200
  [PATCH 4.4 10/20] scsi: cxlflash: Improve EEH recovery time Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-05-05 20:40 +0200
  [PATCH 4.4 19/20] nfsd4: minor NFSv2/v3 write decoding cleanup Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-05-05 20:40 +0200
  [PATCH 4.4 12/20] netlink: Allow direct reclaim for fallback allocation Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-05-05 20:40 +0200
  [PATCH 4.4 14/20] IB/ehca: fix maybe-uninitialized warnings Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-05-05 20:40 +0200
  [PATCH 4.4 13/20] IB/qib: rename BITS_PER_PAGE to RVT_BITS_PER_PAGE Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-05-05 20:40 +0200
  [PATCH 4.4 17/20] ext4 crypto: use dget_parent() in ext4_d_revalidate() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-05-05 20:40 +0200
  [PATCH 4.4 18/20] ext4/fscrypto: avoid RCU lookup in d_revalidate Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-05-05 20:40 +0200
  [PATCH 4.4 03/20] ASoC: intel: Fix PM and non-atomic crash in bytcr drivers Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-05-05 20:40 +0200
  Re: [PATCH 4.4 00/20] 4.4.67-stable review Shuah Khan <shuahkh@osg.samsung.com> - 2017-05-06 04:00 +0200
    Re: [PATCH 4.4 00/20] 4.4.67-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-05-06 05:50 +0200
  Re: [PATCH 4.4 00/20] 4.4.67-stable review Guenter Roeck <linux@roeck-us.net> - 2017-05-08 00:10 +0200

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