On Fri, 2019-03-22 at 10:56 +0800, zhengbin wrote: > When I use dd test a SCSI device which use blk-mq in the following steps: > 1.echo "blocked" >/sys/block/sda/device/state > 2.dd if=/dev/sda of=/mnt/t.log bs=1M count=10 > 3.echo "running" >/sys/block/sda/device/state > dd should finish this work after step 3, unfortunately, still hung. > > After step2, the key code process is like this: > blk_mq_dispatch_rq_list-->scsi_queue_rq-->prep_to_mq > > prep_to_mq will return BLK_STS_RESOURCE, and scsi_queue_rq will transter > it to BLK_STS_DEV_RESOURCE, which means that driver can guarantee that > IO dispatch will be triggered in future when the resource is available. > Need to follow the rule if we set the device state to running. > > Signed-off-by: zhengbin <zhengbi...@huawei.com> > --- > drivers/scsi/scsi_sysfs.c | 5 ﯯ뻕秈媞ޝ, 5 insertions() > > diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c > index 6a9040f..67c214a 100644 > --- a/drivers/scsi/scsi_sysfs.c > @@ -771,6 +771,11 @@ store_state_field(struct device *dev, struct > device_attribute *attr, > > mutex_lock(&sdev->state_mutex); > ret = scsi_device_set_state(sdev, state); > + /* If device state changes to SDEV_RUNNING, we need to run hw queue > + * to avoid io hung. > + */
I think that "device state" should be changed into "the device state", "run hw queue" into "run the queue" and "hung" into "hang". > + if (ret == 0 && state == SDEV_RUNNING) > + blk_mq_run_hw_queues(sdev->request_queue, true); > mutex_unlock(&sdev->state_mutex); > > return ret == 0 ? count : -EINVAL; Anyway, since the code looks fine to me: Reviewed-by: Bart Van Assche <bvanass...@acm.org>
