On 2020-07-08 23:23, Lee Sang Hyun wrote:
> Need to set a request queue like below in sd_shutdown()
> to prevent pending IOs before UFS shutdown.
>
> Change-Id: I2818cf95944d85baa50b626fcf538f19d06d6d54
> Signed-off-by: Lee Sang Hyun <sh425.lee@xxxxxxxxxxx>
> ---
> drivers/scsi/sd.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
> index d90feff..7418d27 100644
> --- a/drivers/scsi/sd.c
> +++ b/drivers/scsi/sd.c
> @@ -3564,6 +3564,8 @@ static int sd_start_stop_device(struct scsi_disk *sdkp, int start)
> static void sd_shutdown(struct device *dev)
> {
> struct scsi_disk *sdkp = dev_get_drvdata(dev);
> + struct request_queue *q = sdp->request_queue;
> + unsigned long flags;
>
> if (!sdkp)
> return; /* this can happen */
> @@ -3580,6 +3582,12 @@ static void sd_shutdown(struct device *dev)
> sd_printk(KERN_NOTICE, sdkp, "Stopping disk\n");
> sd_start_stop_device(sdkp, 0);
> }
> +
> + spin_lock_irqsave(q->queue_lock, flags);
> + queue_flag_set(QUEUE_FLAG_DYING, q);
> + __blk_drain_queue(q, true);
> + queue_flag_set(QUEUE_FLAG_DEAD, q);
> + spin_unlock_irqrestore(q->queue_lock, flags);
> }
This patch is unacceptable because:
(a) It introduces a layering violation. The code added in sd_shutdown()
belongs in the block layer instead of the sd driver.
(b) A description of which problem has been observed and why the sd
driver is being modified is missing.
(c) An explanation is missing why the blk_cleanup_queue() call in
__scsi_remove_device() is not sufficient. As you may know
blk_cleanup_queue() already drains the request queue.
(d) The above patch breaks the kernel build. __blk_drain_queue() was
removed from the kernel almost two years ago. See also commit
a1ce35fa4985 ("block: remove dead elevator code") # v5.0.
Bart.
