From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754219AbaIKNEZ (ORCPT ); Thu, 11 Sep 2014 09:04:25 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:52280 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754215AbaIKNEV (ORCPT ); Thu, 11 Sep 2014 09:04:21 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Christoph Hellwig" , "K. Y. Srinivasan" , "Hannes Reinecke" Date: Thu, 11 Sep 2014 13:32:13 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 023/131] Drivers: scsi: storvsc: Implement a eh_timed_out handler In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.249 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.63-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: "K. Y. Srinivasan" 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 Reviewed-by: Hannes Reinecke [hch: added a better comment explaining the issue] Signed-off-by: Christoph Hellwig [bwh: Backported to 3.2: adjust filename, context] Signed-off-by: Ben Hutchings --- drivers/staging/hv/storvsc_drv.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) --- a/drivers/staging/hv/storvsc_drv.c +++ b/drivers/staging/hv/storvsc_drv.c @@ -32,6 +32,7 @@ #include #include #include +#include #include #include #include @@ -1129,6 +1130,16 @@ static void storvsc_command_completion(s kmem_cache_free(host_dev->request_pool, cmd_request); } +/* + * 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_check_scsi_cmd(struct scsi_cmnd *scmnd) { bool allowed = true; @@ -1305,6 +1316,7 @@ 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_configure = storvsc_device_configure, .cmd_per_lun = 1,