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| author | Gou Hao <gouhao@uniontech.com> | 2023-11-13 16:26:17 +0800 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2024-01-04 23:35:55 -0500 |
| commit | 2bf5eb2a7c22fc3dd011fda2722fd369b1c4608b (patch) | |
| tree | a55b7d0c6f2e164443080ce8022e072d1d842030 /fs/ext4/mballoc.c | |
| parent | c6bfd724098457a1162a7b9fef07af176720055b (diff) | |
| download | linux-2bf5eb2a7c22fc3dd011fda2722fd369b1c4608b.tar.gz | |
ext4: improving calculation of 'fe_{len|start}' in mb_find_extent()
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@uniontech.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20231113082617.11258-1-gouhao@uniontech.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/mballoc.c')
| -rw-r--r-- | fs/ext4/mballoc.c | 13 |
1 files changed, 4 insertions, 9 deletions
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 847dc0fb15735a..0c69f2f8cf8854 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -1957,8 +1957,7 @@ done: 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)); @@ -1976,16 +1975,12 @@ 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)) { |