On Thu, Mar 21, 2019 at 01:43:09PM +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 <zhengbin13@xxxxxxxxxx> > --- > drivers/scsi/scsi_sysfs.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c > index 6a9040f..342e513 100644 > --- a/drivers/scsi/scsi_sysfs.c > +++ b/drivers/scsi/scsi_sysfs.c > @@ -771,9 +771,20 @@ 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. > + */ > + if ((ret == 0) && (state == SDEV_RUNNING)) > + goto out_run_hw_queue; > mutex_unlock(&sdev->state_mutex); > > return ret == 0 ? count : -EINVAL; > + > +out_run_hw_queue: > + mutex_unlock(&sdev->state_mutex); > + blk_mq_run_hw_queues(sdev->request_queue, true); > + > + return count; > } > > static ssize_t > -- > 2.7.4 > Looks fine, Reviewed-by: Ming Lei <ming.lei@xxxxxxxxxx> Thanks, Ming
