From: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
If we have alloc_hint > 0 and don't wrap, we need to recheck
sb->map[index] with hint == 0 to exhaust the map.
For example: we have 8 words to search, index == 4, hint > 0
In sb->map[4] word, we only search [hint, 63] bits in the first
word search. Then we search left 7 words, the sb->map[4] [0, hint-1]
bits aren't searched.
This patch fix it by searching 9 words in this case, so we will
search sb->map[4] the second time at last with hint == 0.
Signed-off-by: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
---
lib/sbitmap.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/lib/sbitmap.c b/lib/sbitmap.c
index ac4027884765..6e098a46be26 100644
--- a/lib/sbitmap.c
+++ b/lib/sbitmap.c
@@ -199,10 +199,18 @@ static int sbitmap_find_bit(struct sbitmap *sb,
unsigned int alloc_hint,
bool wrap)
{
+ unsigned int map_nr = sb->map_nr;
unsigned int i;
int nr = -1;
- for (i = 0; i < sb->map_nr; i++) {
+ /*
+ * If we have alloc_hint > 0 and don't wrap, we need to
+ * recheck sb->map[index] with hint == 0 to exhaust the map.
+ */
+ if (alloc_hint && !wrap)
+ map_nr += 1;
+
+ for (i = 0; i < map_nr; i++) {
nr = sbitmap_find_bit_in_word(&sb->map[index],
min_t(unsigned int,
__map_depth(sb, index),
--
2.41.0
