[PATCH V2 09/13] scsi: force unfreezing queue into atomic mode

[Christoph Hellwig]

On Sat, Jan 22, 2022 at 07:10:50PM +0800, Ming Lei wrote:
> In scsi_disk_release() request queue is frozen for clearing
> disk->private_data, and there can't be any FS IO issued to
> this queue, and only private passthrough request will be handled, so
> force unfreezing queue into atomic mode.
> 
> Signed-off-by: Ming Lei <ming.lei at redhat.com>
> ---
>  drivers/scsi/sd.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
> index 0e73c3f2f381..27f04c860f00 100644
> --- a/drivers/scsi/sd.c
> +++ b/drivers/scsi/sd.c
> @@ -3670,7 +3670,7 @@ static void scsi_disk_release(struct device *dev)
>  	 * in case multiple processes open a /dev/sd... node concurrently.
>  	 */
>  	blk_mq_freeze_queue(q);
> -	blk_mq_unfreeze_queue(q);
> +	__blk_mq_unfreeze_queue(q, true);

I think the right thing here is to drop the freeze/unfreeze pair.
Now that del_gendisk properly freezes the queue, we don't need this
protection as the issue that Bart fixed with it can't happen any more.