Re: [PATCH] ext4/move_extent: use folio_next_pos()

[Zhang Yi]

On 2/22/2026 8:50 PM, Julia Lawall wrote:
> A series of patches such as commit 60a70e61430b ("mm: Use
> folio_next_pos()") replace folio_pos() + folio_size() by
> folio_next_pos().  The former performs x << z + y << z while
> the latter performs (x + y) << z, which is slightly more
> efficient. This case was not taken into account, perhaps
> because the argument is not named folio.
> 
> The change was performed using the following Coccinelle
> semantic patch:
> 
> @@
> expression folio;
> @@
> 
> - folio_pos(folio) + folio_size(folio)
> + folio_next_pos(folio)
> 
> Signed-off-by: Julia Lawall <Julia.Lawall@xxxxxxxx>

Thank you for the patch. Looks good to me.

Reviewed-by: Zhang Yi <yi.zhang@xxxxxxxxxx>

> 
> ---
>  fs/ext4/move_extent.c |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff -u -p a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c
> --- a/fs/ext4/move_extent.c
> +++ b/fs/ext4/move_extent.c
> @@ -224,8 +224,8 @@ static int mext_move_begin(struct mext_d
>  	}
>  
>  	/* Adjust the moving length according to the length of shorter folio. */
> -	move_len = umin(folio_pos(folio[0]) + folio_size(folio[0]) - orig_pos,
> -			folio_pos(folio[1]) + folio_size(folio[1]) - donor_pos);
> +	move_len = umin(folio_next_pos(folio[0]) - orig_pos,
> +			folio_next_pos(folio[1]) - donor_pos);
>  	move_len >>= blkbits;
>  	if (move_len < mext->orig_map.m_len)
>  		mext->orig_map.m_len = move_len;
> 
> 
>