From: wuchi <wuchi.zero@xxxxxxxxx> commit fbb564a557809466c171b95f8d593a0972450ff2 upstream. 1. Getting next index before continue branch. 2. Checking free bits when setting the target bits. Otherwise, it may reuse the busying bits. Signed-off-by: wuchi <wuchi.zero@xxxxxxxxx> Reviewed-by: Martin Wilck <mwilck@xxxxxxxx> Link: https://lore.kernel.org/r/20220605145835.26916-1-wuchi.zero@xxxxxxxxx Fixes: 9672b0d43782 ("sbitmap: add __sbitmap_queue_get_batch()") Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- lib/sbitmap.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/lib/sbitmap.c b/lib/sbitmap.c index ae4fd4de9ebe..29eb0484215a 100644 --- a/lib/sbitmap.c +++ b/lib/sbitmap.c @@ -528,7 +528,7 @@ unsigned long __sbitmap_queue_get_batch(struct sbitmap_queue *sbq, int nr_tags, sbitmap_deferred_clear(map); if (map->word == (1UL << (map_depth - 1)) - 1) - continue; + goto next; nr = find_first_zero_bit(&map->word, map_depth); if (nr + nr_tags <= map_depth) { @@ -539,6 +539,8 @@ unsigned long __sbitmap_queue_get_batch(struct sbitmap_queue *sbq, int nr_tags, get_mask = ((1UL << map_tags) - 1) << nr; do { val = READ_ONCE(map->word); + if ((val & ~get_mask) != val) + goto next; ret = atomic_long_cmpxchg(ptr, val, get_mask | val); } while (ret != val); get_mask = (get_mask & ~ret) >> nr; @@ -549,6 +551,7 @@ unsigned long __sbitmap_queue_get_batch(struct sbitmap_queue *sbq, int nr_tags, return get_mask; } } +next: /* Jump to next index. */ if (++index >= sb->map_nr) index = 0; -- 2.37.0
