linux-kernel - Re: [PATCH v1 2/3] fuse: use offset_in_folio() for large folio offset calculations

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Message-ID: <20260119082327.2029-1-luochunsheng@ustc.edu>
Date: Mon, 19 Jan 2026 16:23:27 +0800
From: Chunsheng Luo <luochunsheng@...c.edu>
To: miklos@...redi.hu
Cc: amir73il@...il.com,
	linux-fsdevel@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 2/3] fuse: use offset_in_folio() for large folio offset calculations

On 1/17/26 7:56 AM, Joanne Koong wrote:
> Use offset_in_folio() instead of manually calculating the folio offset.
>
> Signed-off-by: Joanne Koong <joannelkoong@...il.com>
> ---
>   fs/fuse/dev.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
> index 698289b5539e..4dda4e24cc90 100644
> --- a/fs/fuse/dev.c
> +++ b/fs/fuse/dev.c
> @@ -1812,7 +1812,7 @@ static int fuse_notify_store(struct fuse_conn *fc, unsigned int size,
>           if (IS_ERR(folio))
>               goto out_iput;
>   -        folio_offset = ((index - folio->index) << PAGE_SHIFT) + offset;
> +        folio_offset = offset_in_folio(folio, outarg.offset);

offset is a loop variable, and later offset maybe set to 0. Replacing it
with outarg.offset here would change the behavior. The same below.
Will this cause any problems?

Thanks,
Chunsheng Luo

>           nr_bytes = min_t(unsigned, num, folio_size(folio) - folio_offset);
>           nr_pages = DIV_ROUND_UP(offset + nr_bytes, PAGE_SIZE);
>   @@ -1916,7 +1916,7 @@ static int fuse_retrieve(struct fuse_mount *fm, struct inode *inode,
>           if (IS_ERR(folio))
>               break;
>   -        folio_offset = ((index - folio->index) << PAGE_SHIFT) + offset;
> +        folio_offset = offset_in_folio(folio, outarg->offset);
>           nr_bytes = min(folio_size(folio) - folio_offset, num);
>           nr_pages = DIV_ROUND_UP(offset + nr_bytes, PAGE_SIZE);
>