On Mon 13-11-23 16:26:17, Gou Hao wrote:
> After first execution of mb_find_order_for_block():
>
> 'fe_start' is the value of 'block' passed in mb_find_extent().
>
> 'fe_len' is the difference between the length of order-chunk and
> remainder of the block divided by order-chunk.
>
> And 'next' does not require initialization after above modifications.
>
> Signed-off-by: Gou Hao <gouhao@xxxxxxxxxxxxx>
Ah, nice simplification! Feel free to add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
Honza
> ---
> fs/ext4/mballoc.c | 13 ++++---------
> 1 file changed, 4 insertions(+), 9 deletions(-)
>
> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
> index 454d5612641e..d3f985f7cab8 100644
> --- a/fs/ext4/mballoc.c
> +++ b/fs/ext4/mballoc.c
> @@ -1958,8 +1958,7 @@ static void mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b,
> static int mb_find_extent(struct ext4_buddy *e4b, int block,
> int needed, struct ext4_free_extent *ex)
> {
> - int next = block;
> - int max, order;
> + int max, order, next;
> void *buddy;
>
> assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
> @@ -1977,16 +1976,12 @@ static int mb_find_extent(struct ext4_buddy *e4b, int block,
>
> /* find actual order */
> order = mb_find_order_for_block(e4b, block);
> - block = block >> order;
>
> - ex->fe_len = 1 << order;
> - ex->fe_start = block << order;
> + ex->fe_len = (1 << order) - (block & ((1 << order) - 1));
> + ex->fe_start = block;
> ex->fe_group = e4b->bd_group;
>
> - /* calc difference from given start */
> - next = next - ex->fe_start;
> - ex->fe_len -= next;
> - ex->fe_start += next;
> + block = block >> order;
>
> while (needed > ex->fe_len &&
> mb_find_buddy(e4b, order, &max)) {
> --
> 2.20.1
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
