linux-kernel - Re: [PATCH 4/7] iomap: simplify direct io validity check

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Message-ID: <f8f0a124-74f6-4fb8-ae11-c6bce2deb0fd@suse.de>
Date: Mon, 4 Aug 2025 08:57:08 +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 4/7] iomap: 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>
> ---
>   fs/iomap/direct-io.c | 3 +--
>   1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
> index 6f25d4cfea9f7..2c1a45e46dc75 100644
> --- a/fs/iomap/direct-io.c
> +++ b/fs/iomap/direct-io.c
> @@ -337,8 +337,7 @@ static int iomap_dio_bio_iter(struct iomap_iter *iter, struct iomap_dio *dio)
>   	u64 copied = 0;
>   	size_t orig_count;
>   
> -	if ((pos | length) & (bdev_logical_block_size(iomap->bdev) - 1) ||
> -	    !bdev_iter_is_aligned(iomap->bdev, dio->submit.iter))
> +	if ((pos | length) & (bdev_logical_block_size(iomap->bdev) - 1))
>   		return -EINVAL;
>   
>   	if (dio->flags & IOMAP_DIO_WRITE) {

Similar here: why a bitwise or?

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