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Diffstat (limited to 'lib/sbitmap.c')
-rw-r--r--lib/sbitmap.c31
1 files changed, 14 insertions, 17 deletions
diff --git a/lib/sbitmap.c b/lib/sbitmap.c
index 2fedf07a9db5..a39b1a877366 100644
--- a/lib/sbitmap.c
+++ b/lib/sbitmap.c
@@ -599,38 +599,34 @@ static struct sbq_wait_state *sbq_wake_ptr(struct sbitmap_queue *sbq)
return NULL;
}
-static bool __sbq_wake_up(struct sbitmap_queue *sbq, int nr)
+static bool __sbq_wake_up(struct sbitmap_queue *sbq)
{
struct sbq_wait_state *ws;
- int wake_batch, wait_cnt, cur;
+ unsigned int wake_batch;
+ int wait_cnt;
ws = sbq_wake_ptr(sbq);
- if (!ws || !nr)
+ if (!ws)
return false;
- wake_batch = READ_ONCE(sbq->wake_batch);
- cur = atomic_read(&ws->wait_cnt);
- do {
- if (cur <= 0)
- return true;
- wait_cnt = cur - nr;
- } while (!atomic_try_cmpxchg(&ws->wait_cnt, &cur, wait_cnt));
-
+ wait_cnt = atomic_dec_return(&ws->wait_cnt);
/*
* For concurrent callers of this, callers should call this function
* again to wakeup a new batch on a different 'ws'.
*/
- if (!waitqueue_active(&ws->wait))
+ if (wait_cnt < 0 || !waitqueue_active(&ws->wait))
return true;
if (wait_cnt > 0)
return false;
+ wake_batch = READ_ONCE(sbq->wake_batch);
+
/*
* Wake up first in case that concurrent callers decrease wait_cnt
* while waitqueue is empty.
*/
- wake_up_nr(&ws->wait, max(wake_batch, nr));
+ wake_up_nr(&ws->wait, wake_batch);
/*
* Pairs with the memory barrier in sbitmap_queue_resize() to
@@ -655,11 +651,12 @@ static bool __sbq_wake_up(struct sbitmap_queue *sbq, int nr)
return false;
}
-void sbitmap_queue_wake_up(struct sbitmap_queue *sbq, int nr)
+void sbitmap_queue_wake_up(struct sbitmap_queue *sbq)
{
- while (__sbq_wake_up(sbq, nr))
+ while (__sbq_wake_up(sbq))
;
}
+EXPORT_SYMBOL_GPL(sbitmap_queue_wake_up);
static inline void sbitmap_update_cpu_hint(struct sbitmap *sb, int cpu, int tag)
{
@@ -696,7 +693,7 @@ void sbitmap_queue_clear_batch(struct sbitmap_queue *sbq, int offset,
atomic_long_andnot(mask, (atomic_long_t *) addr);
smp_mb__after_atomic();
- sbitmap_queue_wake_up(sbq, nr_tags);
+ sbitmap_queue_wake_up(sbq);
sbitmap_update_cpu_hint(&sbq->sb, raw_smp_processor_id(),
tags[nr_tags - 1] - offset);
}
@@ -724,7 +721,7 @@ void sbitmap_queue_clear(struct sbitmap_queue *sbq, unsigned int nr,
* waiter. See the comment on waitqueue_active().
*/
smp_mb__after_atomic();
- sbitmap_queue_wake_up(sbq, 1);
+ sbitmap_queue_wake_up(sbq);
sbitmap_update_cpu_hint(&sbq->sb, cpu, nr);
}
EXPORT_SYMBOL_GPL(sbitmap_queue_clear);