On Wed, Aug 24, 2022 at 01:14:40PM -0700, Keith Busch wrote:

 
-static bool __sbq_wake_up(struct sbitmap_queue *sbq)
+static bool __sbq_wake_up(struct sbitmap_queue *sbq, int *nr)
 {
 	struct sbq_wait_state *ws;
-	unsigned int wake_batch;
-	int wait_cnt;
+	int wake_batch, wait_cnt, sub, cur;
 
 	ws = sbq_wake_ptr(sbq);
 	if (!ws)
 		return false;
 
-	wait_cnt = atomic_dec_return(&ws->wait_cnt);
+	wake_batch = READ_ONCE(sbq->wake_batch);
+	do {
+		cur = atomic_read(&ws->wait_cnt);

I think the above statement is not needed if we use atomic_try_cmpxchg
as the old value is updated in that function itself.
https://docs.kernel.org/staging/index.html?highlight=atomic_try_cmpxchg#atomic-types

+		sub = min3(wake_batch, *nr, cur);
+		wait_cnt = cur - sub;
+	} while (!atomic_try_cmpxchg(&ws->wait_cnt, &cur, wait_cnt));
+
+	*nr -= sub;
+
 	/*

-- 
Pankaj Raghav