Re: [PATCH 5/7] Drivers: scsi: storvsc: Implement a timedout handler

Hannes Reinecke
2014-07-14T06:16:55Z

On 07/12/2014 06:48 PM, K. Y. Srinivasan wrote:
> 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>
> Cc: <stable@vger.kernel.org>
> ---
> drivers/scsi/storvsc_drv.c | 10 ++++++++++
> 1 files changed, 10 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
> index 7e8a642..3516761 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>
> @@ -1518,6 +1519,14 @@ static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
> return SUCCESS;
> }
>
> +static enum blk_eh_timer_return storvsc_timeout_handler(struct scsi_cmnd *scmnd)
> +{
> + /*
> + * The host will respond; ask for more time.
> + */
> + return BLK_EH_RESET_TIMER;
> +}
> +
> static bool storvsc_scsi_cmd_ok(struct scsi_cmnd *scmnd)
> {
> bool allowed = true;
> @@ -1697,6 +1706,7 @@ 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_timeout_handler,
> .slave_alloc = storvsc_device_alloc,
> .slave_destroy = storvsc_device_destroy,
> .slave_configure = storvsc_device_configure,
>
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
--
Dr. Hannes Reinecke zSeries & Storage
hare@suse.de +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)