From fe66483156050f4eb63c4a1988f3b439e6c9ff2a Mon Sep 17 00:00:00 2001
From: Davidlohr Bueso <dave@stgolabs.net>
Date: Wed, 29 Jan 2020 10:10:41 -0800
Subject: [PATCH] Bluetooth: optimize barrier usage for Rmw atomics
Git-commit: fe66483156050f4eb63c4a1988f3b439e6c9ff2a
Patch-mainline: v5.7-rc1
References: jsc#SLE-13430
Use smp_mb__before_atomic() instead of smp_mb() and avoid the
unnecessary barrier for non LL/SC architectures, such as x86.
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
net/bluetooth/hidp/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/bluetooth/hidp/core.c b/net/bluetooth/hidp/core.c
index bef84b95e2c4..3b4fa27a44e6 100644
--- a/net/bluetooth/hidp/core.c
+++ b/net/bluetooth/hidp/core.c
@@ -1279,7 +1279,7 @@ static int hidp_session_thread(void *arg)
add_wait_queue(sk_sleep(session->intr_sock->sk), &intr_wait);
/* This memory barrier is paired with wq_has_sleeper(). See
* sock_poll_wait() for more information why this is needed. */
- smp_mb();
+ smp_mb__before_atomic();
/* notify synchronous startup that we're ready */
atomic_inc(&session->state);
--
2.16.4