Re: [PATCH v2] blk-mq: fix a hung issue when set device state to blocked and restore running

[Bart Van Assche <bvanassche@xxxxxxx>]

On 3/20/19 8:21 PM, zhengbin wrote:
> diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
> index 6a9040f..ce60408 100644
> --- a/drivers/scsi/scsi_sysfs.c
> +++ b/drivers/scsi/scsi_sysfs.c
> @@ -770,7 +770,20 @@ store_state_field(struct device *dev, struct device_attribute *attr,
>   		return -EINVAL;
>
>   	mutex_lock(&sdev->state_mutex);
> +	enum scsi_device_state oldstate = sdev->sdev_state;
>   	ret = scsi_device_set_state(sdev, state);
> +	if (ret == 0) {
> +		/* If device use blk-mq, the device state changes from
> +		 * SDEV_BLOCK to SDEV_RUNNING, we need to run hw queue
> +		 * to avoid io hung.
> +		 */
> +		if ((state == SDEV_RUNNING) && (oldstate == SDEV_BLOCK)) {
> +			struct request_queue *q = sdev->request_queue;
> +
> +			if (q->mq_ops)
> +				blk_mq_run_hw_queues(q, true);
> +		}
> +	}
>   	mutex_unlock(&sdev->state_mutex);

Hi Zhengbin,

In addition to what Ming asked, please combine the nested if-statements 
into a single if-statement and leave out the superfluous parentheses.

Thanks,

Bart.