linux-kernel - Re: [PATCH 3/7] block: simplify direct io validity check

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Message-ID: <065d699a-1edb-4712-9857-021c58c5e5c2@suse.de>
Date: Mon, 4 Aug 2025 08:55:36 +0200
From: Hannes Reinecke <hare@...e.de>
To: Keith Busch <kbusch@...a.com>, linux-block@...r.kernel.org,
 linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: snitzer@...nel.org, axboe@...nel.dk, dw@...idwei.uk, brauner@...nel.org,
 Keith Busch <kbusch@...nel.org>
Subject: Re: [PATCH 3/7] block: simplify direct io validity check

On 8/2/25 01:47, Keith Busch wrote:
> From: Keith Busch <kbusch@...nel.org>
> 
> The block layer checks all the segments for validity later, so no need
> for an early check. Just reduce it to a simple position and total length
> and defer the segment checks to the block layer.
> 
> Signed-off-by: Keith Busch <kbusch@...nel.org>
> ---
>   block/fops.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/block/fops.c b/block/fops.c
> index 82451ac8ff25d..820902cf10730 100644
> --- a/block/fops.c
> +++ b/block/fops.c
> @@ -38,8 +38,8 @@ static blk_opf_t dio_bio_write_op(struct kiocb *iocb)
>   static bool blkdev_dio_invalid(struct block_device *bdev, struct kiocb *iocb,
>   				struct iov_iter *iter)
>   {
> -	return iocb->ki_pos & (bdev_logical_block_size(bdev) - 1) ||
> -		!bdev_iter_is_aligned(bdev, iter);
> +	return (iocb->ki_pos | iov_iter_count(iter)) &
> +			(bdev_logical_block_size(bdev) - 1);

Bitwise or? Sure?

>   }
>   
>   #define DIO_INLINE_BIO_VECS 4

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                  Kernel Storage Architect
hare@...e.de                                +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich