In steal_from_bitmap_to_front function, it finds last_zero_bit from i
using for_each_clear_bit.
But this makes some overhead that it starts from the 0 bit.
By adding find_last_zero_bit, I try to remove this overhead and
improve readibility.
Signed-off-by: Levi Yun <ppbuk5246@xxxxxxxxx>
---
fs/btrfs/free-space-cache.c | 22 ++++++++--------------
1 file changed, 8 insertions(+), 14 deletions(-)
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index af0013d3df63..6d393c834fdd 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -2372,7 +2372,6 @@ static bool steal_from_bitmap_to_front(struct btrfs_free_space_ctl *ctl,
u64 bitmap_offset;
unsigned long i;
unsigned long j;
- unsigned long prev_j;
u64 bytes;
bitmap_offset = offset_to_bitmap(ctl, info->offset);
@@ -2388,20 +2387,15 @@ static bool steal_from_bitmap_to_front(struct btrfs_free_space_ctl *ctl,
return false;
i = offset_to_bit(bitmap->offset, ctl->unit, info->offset) - 1;
- j = 0;
- prev_j = (unsigned long)-1;
- for_each_clear_bit_from(j, bitmap->bitmap, BITS_PER_BITMAP) {
- if (j > i)
- break;
- prev_j = j;
- }
- if (prev_j == i)
- return false;
+ j = find_last_zero_bit(bitmap->bitmap, i);
- if (prev_j == (unsigned long)-1)
- bytes = (i + 1) * ctl->unit;
- else
- bytes = (i - prev_j) * ctl->unit;
+ if (j == i) {
+ if (!test_bit(i, bitmap->bitmap))
+ return false;
+ else
+ bytes = (i + 1) * ctl->unit;
+ } else
+ bytes = (i - j) * ctl->unit;
info->offset -= bytes;
info->bytes += bytes;
--
2.27.0
