ping
On 2019/3/22 11:01, Ming Lei wrote:
> On Fri, Mar 22, 2019 at 10:56:46AM +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 +++++
>> 1 file changed, 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
>> +++ b/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.
>> + */
>> + if (ret == 0 && state == SDEV_RUNNING)
>> + blk_mq_run_hw_queues(sdev->request_queue, true);
>> mutex_unlock(&sdev->state_mutex);
>
> Reviewed-by: Ming Lei <ming....@redhat.com>
>
>
> Thanks,
> Ming
>
> .
>
