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| author | K. Y. Srinivasan <kys@microsoft.com> | 2014-07-12 18:48:30 +0200 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2014-07-25 23:17:03 +0200 |
| commit | 56b26e69c8283121febedd12b3cc193384af46b9 (patch) | |
| tree | 7e62acbb51256914944320c8aa54111bfbbf663f /drivers/scsi/storvsc_drv.c | |
| parent | Drivers: scsi: storvsc: Fix a bug in handling VMBUS protocol version (diff) | |
| download | linux-56b26e69c8283121febedd12b3cc193384af46b9.tar.xz linux-56b26e69c8283121febedd12b3cc193384af46b9.zip | |
Drivers: scsi: storvsc: Implement a eh_timed_out handler
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>
Cc: <stable@vger.kernel.org>
[hch: added a better comment explaining the issue]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'drivers/scsi/storvsc_drv.c')
| -rw-r--r-- | drivers/scsi/storvsc_drv.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c index 7e8a64251681..2b8595b7ad45 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 +1519,16 @@ 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) +{ + return BLK_EH_RESET_TIMER; +} + static bool storvsc_scsi_cmd_ok(struct scsi_cmnd *scmnd) { bool allowed = true; @@ -1697,6 +1708,7 @@ 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, |