*/
static inline bool sbitmap_deferred_clear(struct sbitmap_word *map)
{
- unsigned long mask, val;
- bool ret = false;
- unsigned long flags;
+ unsigned long mask;
- spin_lock_irqsave(&map->swap_lock, flags);
-
- if (!map->cleared)
- goto out_unlock;
+ if (!READ_ONCE(map->cleared))
+ return false;
/*
* First get a stable cleared mask, setting the old mask to 0.
/*
* Now clear the masked bits in our free word
*/
- do {
- val = map->word;
- } while (cmpxchg(&map->word, val, val & ~mask) != val);
-
- ret = true;
-out_unlock:
- spin_unlock_irqrestore(&map->swap_lock, flags);
- return ret;
+ atomic_long_andnot(mask, (atomic_long_t *)&map->word);
+ BUILD_BUG_ON(sizeof(atomic_long_t) != sizeof(map->word));
+ return true;
}
int sbitmap_init_node(struct sbitmap *sb, unsigned int depth, int shift,
for (i = 0; i < sb->map_nr; i++) {
sb->map[i].depth = min(depth, bits_per_word);
depth -= sb->map[i].depth;
- spin_lock_init(&sb->map[i].swap_lock);
}
return 0;
}
static int __sbitmap_get_word(unsigned long *word, unsigned long depth,
unsigned int hint, bool wrap)
{
- unsigned int orig_hint = hint;
int nr;
+ /* don't wrap if starting from 0 */
+ wrap = wrap && hint;
+
while (1) {
nr = find_next_zero_bit(word, depth, hint);
if (unlikely(nr >= depth)) {
* offset to 0 in a failure case, so start from 0 to
* exhaust the map.
*/
- if (orig_hint && hint && wrap) {
- hint = orig_hint = 0;
+ if (hint && wrap) {
+ hint = 0;
continue;
}
return -1;