Re: [PATCH] ublk: optimize ublk_rq_has_data()

[Ming Lei <tom.leiming@gmail.com>]

On Tue, Apr 21, 2026 at 01:47:42PM -0600, Caleb Sander Mateos wrote:
> ublk_rq_has_data() currently uses bio_has_data(), which involves 2
> indirections and several branches. Use blk_rq_bytes() instead, which
> performs a single indirection with no branches.
> 
> Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
> ---
>  drivers/block/ublk_drv.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
> index ef8a0705e68b..5f9b3c3876f4 100644
> --- a/drivers/block/ublk_drv.c
> +++ b/drivers/block/ublk_drv.c
> @@ -1172,11 +1172,11 @@ static inline struct ublk_queue *ublk_get_queue(struct ublk_device *dev,
>  	return dev->queues[qid];
>  }
>  
>  static inline bool ublk_rq_has_data(const struct request *rq)
>  {
> -	return bio_has_data(rq->bio);
> +	return blk_rq_bytes(rq);
>  }

blk_rq_bytes() doesn't return the actual payload data bytes, such as,
discard command, but bio_has_data() does.


thanks,
Ming