| Message ID | 20220605145835.26916-1-wuchi.zero@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | lib/sbitmap: Fix invalid loop in __sbitmap_queue_get_batch() | expand |
Ping.... wuchi <wuchi.zero@gmail.com> 于2022年6月5日周日 22:58写道： > > 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@gmail.com> > --- > 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; > -- > 2.20.1 >
On Sun, 2022-06-05 at 22:58 +0800, wuchi wrote: > 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@gmail.com> Reviewed-by: Martin Wilck <mwilck@suse.com> > --- > 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;
On 6/5/22 8:58 AM, wuchi wrote: > 1. Getting next index before continue branch. > 2. Checking free bits when setting the target bits. Otherwise, > it may reuse the busying bits. Applied with: Fixes: 9672b0d43782 ("sbitmap: add __sbitmap_queue_get_batch()") added as well.
On Sun, 5 Jun 2022 22:58:35 +0800, wuchi wrote: > 1. Getting next index before continue branch. > 2. Checking free bits when setting the target bits. Otherwise, > it may reuse the busying bits. > > Applied, thanks! [1/1] lib/sbitmap: Fix invalid loop in __sbitmap_queue_get_batch() (no commit info) Best regards,
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;
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@gmail.com> --- lib/sbitmap.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)