On Fri, Feb 10, 2023 at 03:48:17AM +0800, Kemeng Shi wrote:
> We always adjust first to even number and adjust last to odd number, so
> first == last will never happen. Remove this dead check.
>
> Signed-off-by: Kemeng Shi <shikemeng@xxxxxxxxxxxxxxx>
> ---
> fs/ext4/mballoc.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
> index bdabe0d81d4a..0fdbf16ac180 100644
> --- a/fs/ext4/mballoc.c
> +++ b/fs/ext4/mballoc.c
> @@ -1718,7 +1718,8 @@ static void mb_buddy_mark_free(struct ext4_buddy *e4b, int first, int last)
> break;
> order++;
>
> - if (first == last || !(buddy2 = mb_find_buddy(e4b, order, &max))) {
> + buddy2 = mb_find_buddy(e4b, order, &max);
> + if (!buddy2) {
> mb_clear_bits(buddy, first, last - first + 1);
> e4b->bd_info->bb_counters[order - 1] += last - first + 1;
> break;
> --
> 2.30.0
>
Okay, so I checked the code and seems like you are right. There is can't be any
scenario where (first == last) after the calls to mb_buddy_adjust_border().
However, I'm a bit hesitant to give my Reviewed by since buddy algo is still a
bit confusing to me and I might be missing some weird edge case. Maybe someone
can help double check this.
