linux-kernel - [PATCH 6/6] sbitmap: check ws_active before check waitqueues

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Message-ID: <20230720094555.1397621-7-chengming.zhou@linux.dev>
Date:   Thu, 20 Jul 2023 17:45:55 +0800
From:   chengming.zhou@...ux.dev
To:     axboe@...nel.dk, osandov@...com, ming.lei@...hat.com,
        kbusch@...nel.org, krisman@...e.de
Cc:     linux-kernel@...r.kernel.org, linux-block@...r.kernel.org,
        zhouchengming@...edance.com
Subject: [PATCH 6/6] sbitmap: check ws_active before check waitqueues

From: Chengming Zhou <zhouchengming@...edance.com>

When !ws_active, we don't need to check waitqueues at all. So add
this check in sbitmap_queue_wake_all(), like we do in
sbitmap_queue_wake_up().

Signed-off-by: Chengming Zhou <zhouchengming@...edance.com>
---
 lib/sbitmap.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/lib/sbitmap.c b/lib/sbitmap.c
index 6778ab3fc6a5..38c265e4ef9d 100644
--- a/lib/sbitmap.c
+++ b/lib/sbitmap.c
@@ -672,6 +672,10 @@ void sbitmap_queue_wake_all(struct sbitmap_queue *sbq)
 	 * sbitmap_queue_wake_up().
 	 */
 	smp_mb();
+
+	if (!atomic_read(&sbq->ws_active))
+		return;
+
 	wake_index = READ_ONCE(sbq->wake_index);
 	for (i = 0; i < SBQ_WAIT_QUEUES; i++) {
 		struct sbq_wait_state *ws = &sbq->ws[wake_index];
-- 
2.41.0