linux-kernel - Re: [PATCH RESEND v2 06/10] block, bfq: remove redundant bfqd->rq_in_driver > 0 check in bfq_add

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Message-ID: <20230102155415.pvl57qtzjk2acwf6@quack3>
Date:   Mon, 2 Jan 2023 16:54:15 +0100
From:   Jan Kara <jack@...e.cz>
To:     Kemeng Shi <shikemeng@...weicloud.com>
Cc:     paolo.valente@...aro.org, axboe@...nel.dk,
        linux-block@...r.kernel.org, linux-kernel@...r.kernel.org,
        jack@...e.cz, hch@....de, damien.lemoal@....com
Subject: Re: [PATCH RESEND v2 06/10] block, bfq: remove redundant
 bfqd->rq_in_driver > 0 check in bfq_add_request

On Fri 23-12-22 03:16:37, Kemeng Shi wrote:
> The bfqd->rq_in_driver > 0 check is along with previous
> "bfqd->rq_in_driver == 0 ||" check, so no need to re-check
> bfqd->rq_in_driver > 0.
> 
> Signed-off-by: Kemeng Shi <shikemeng@...weicloud.com>

I have nothing against this but OTOH in this complex condition the original
version looks more readable than the new one to me.

								Honza

> ---
>  block/bfq-iosched.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
> index ebcafe3c4c3b..7c91d16dbf6f 100644
> --- a/block/bfq-iosched.c
> +++ b/block/bfq-iosched.c
> @@ -2204,8 +2204,7 @@ static void bfq_add_request(struct request *rq)
>  		 */
>  		if (bfqq == bfqd->in_service_queue &&
>  		    (bfqd->rq_in_driver == 0 ||
> -		     (bfqq->last_serv_time_ns > 0 &&
> -		      bfqd->rqs_injected && bfqd->rq_in_driver > 0)) &&
> +		     (bfqq->last_serv_time_ns > 0 && bfqd->rqs_injected)) &&
>  		    time_is_before_eq_jiffies(bfqq->decrease_time_jif +
>  					      msecs_to_jiffies(10))) {
>  			bfqd->last_empty_occupied_ns = ktime_get_ns();
> -- 
> 2.30.0
> 
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR