path: root/drivers/scsi
diff options
authorK. Y. Srinivasan <kys@microsoft.com>2014-07-12 09:48:30 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-09-17 09:03:58 -0700
commit7afc3ac1263be1a6f2ef76d76ff41615a0c795d3 (patch)
tree0af363b5cdafb48018477d18a2f4f8d88483736c /drivers/scsi
parentd08ed7a370531ca47694498de8b5e32966545884 (diff)
Drivers: scsi: storvsc: Implement a eh_timed_out handler
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>
Diffstat (limited to 'drivers/scsi')
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
index 91b76cea3e3c..34a8f526908f 100644
--- 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>
@@ -1285,6 +1286,16 @@ static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
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)
static bool storvsc_scsi_cmd_ok(struct scsi_cmnd *scmnd)
bool allowed = true;
@@ -1444,6 +1455,7 @@ static struct scsi_host_template scsi_driver = {
.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,