From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: [PATCH] virtio_scsi: let host do exception handling Date: Wed, 21 Jun 2017 16:35:46 +0200 Message-ID: <20170621143546.5826-1-pbonzini@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org Cc: "James E.J. Bottomley" , "Martin K. Petersen" , linux-scsi@vger.kernel.org, stable@vger.kernel.org, Douglas Miller List-Id: virtualization@lists.linuxfoundation.org virtio_scsi tries to do exception handling after the default 30 seconds timeout expires. However, it's better to let the host control the timeout, otherwise with a heavy I/O load it is likely that an abort will also timeout. This leads to fatal errors like filesystems going offline. Disable the 'sd' timeout and allow the host to do exception handling, following the precedent of the storvsc driver. Hannes has a proposal to introduce timeouts in virtio, but this provides an immediate solution for stable kernels too. Reported-by: Douglas Miller Cc: "James E.J. Bottomley" Cc: "Martin K. Petersen" Cc: Hannes Reinecke Cc: linux-scsi@vger.kernel.org Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini --- drivers/scsi/virtio_scsi.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c index f8dbfeee6c63..55d344ea6869 100644 --- a/drivers/scsi/virtio_scsi.c +++ b/drivers/scsi/virtio_scsi.c @@ -796,6 +796,16 @@ static int virtscsi_map_queues(struct Scsi_Host *shost) return blk_mq_virtio_map_queues(&shost->tag_set, vscsi->vdev, 2); } +/* + * The host guarantees to respond to each command, although I/O latencies might + * be higher than on bare meta. Reset the timer unconditionally to give the + * host a chance to perform EH. + */ +static enum blk_eh_timer_return virtscsi_eh_timed_out(struct scsi_cmnd *scmnd) +{ + return BLK_EH_RESET_TIMER; +} + static struct scsi_host_template virtscsi_host_template_single = { .module = THIS_MODULE, .name = "Virtio SCSI HBA", @@ -806,6 +816,7 @@ static struct scsi_host_template virtscsi_host_template_single = { .change_queue_depth = virtscsi_change_queue_depth, .eh_abort_handler = virtscsi_abort, .eh_device_reset_handler = virtscsi_device_reset, + .eh_timed_out = virtscsi_eh_timed_out, .slave_alloc = virtscsi_device_alloc, .can_queue = 1024, @@ -826,6 +837,7 @@ static struct scsi_host_template virtscsi_host_template_multi = { .change_queue_depth = virtscsi_change_queue_depth, .eh_abort_handler = virtscsi_abort, .eh_device_reset_handler = virtscsi_device_reset, + .eh_timed_out = virtscsi_eh_timed_out, .can_queue = 1024, .dma_boundary = UINT_MAX, -- 2.13.0