Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   chengming.zhou@linux.dev
To:     axboe@kernel.dk, osandov@fb.com, ming.lei@redhat.com,
        kbusch@kernel.org, krisman@suse.de
Cc:     linux-kernel@vger.kernel.org, linux-block@vger.kernel.org,
        zhouchengming@bytedance.com
Subject: [PATCH 6/6] sbitmap: check ws_active before check waitqueues
Date:   Thu, 20 Jul 2023 17:45:55 +0800
Message-ID: <20230720094555.1397621-7-chengming.zhou@linux.dev>
In-Reply-To: <20230720094555.1397621-1-chengming.zhou@linux.dev>
References: <20230720094555.1397621-1-chengming.zhou@linux.dev>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Chengming Zhou <zhouchengming@bytedance.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@bytedance.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