--- /dev/null
+From 56b26e69c8283121febedd12b3cc193384af46b9 Mon Sep 17 00:00:00 2001
+From: "K. Y. Srinivasan" <kys@microsoft.com>
+Date: Sat, 12 Jul 2014 09:48:30 -0700
+Subject: Drivers: scsi: storvsc: Implement a eh_timed_out handler
+
+From: "K. Y. Srinivasan" <kys@microsoft.com>
+
+commit 56b26e69c8283121febedd12b3cc193384af46b9 upstream.
+
+On Azure, we have seen instances of unbounded I/O latencies. To deal with
+this issue, implement handler that can reset the timeout. Note that the
+host gaurantees that it will respond to each command that has been issued.
+
+Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
+Reviewed-by: Hannes Reinecke <hare@suse.de>
+[hch: added a better comment explaining the issue]
+Signed-off-by: Christoph Hellwig <hch@lst.de>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ drivers/scsi/storvsc_drv.c | 12 ++++++++++++
+ 1 file changed, 12 insertions(+)
+
+--- a/drivers/scsi/storvsc_drv.c
++++ b/drivers/scsi/storvsc_drv.c
+@@ -33,6 +33,7 @@
+ #include <linux/device.h>
+ #include <linux/hyperv.h>
+ #include <linux/mempool.h>
++#include <linux/blkdev.h>
+ #include <scsi/scsi.h>
+ #include <scsi/scsi_cmnd.h>
+ #include <scsi/scsi_host.h>
+@@ -1518,6 +1519,16 @@ static int storvsc_host_reset_handler(st
+ return SUCCESS;
+ }
+
++/*
++ * The host guarantees to respond to each command, although I/O latencies might
++ * be unbounded on Azure. Reset the timer unconditionally to give the host a
++ * chance to perform EH.
++ */
++static enum blk_eh_timer_return storvsc_eh_timed_out(struct scsi_cmnd *scmnd)
++{
++ return BLK_EH_RESET_TIMER;
++}
++
+ static bool storvsc_scsi_cmd_ok(struct scsi_cmnd *scmnd)
+ {
+ bool allowed = true;
+@@ -1687,6 +1698,7 @@ static struct scsi_host_template scsi_dr
+ .bios_param = storvsc_get_chs,
+ .queuecommand = storvsc_queuecommand,
+ .eh_host_reset_handler = storvsc_host_reset_handler,
++ .eh_timed_out = storvsc_eh_timed_out,
+ .slave_alloc = storvsc_device_alloc,
+ .slave_destroy = storvsc_device_destroy,
+ .slave_configure = storvsc_device_configure,