on 2/14/2023 3:50 AM, Ojaswin Mujoo wrote:
> 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.
Hi, could anyone help double check this patch and patch 18/21 "ext4: remove
unnecessary goto in ext4_mb_mark_diskspace_used" in the same patchset. Thanks.
--
Best wishes
Kemeng Shi
