From: Davidlohr Bueso <dave@stgolabs.net>
To: marcel@holtmann.org
Cc: johan.hedberg@gmail.com, linux-kernel@vger.kernel.org,
linux-bluetooth@vger.kernel.org,
Davidlohr Bueso <dave@stgolabs.net>,
Davidlohr Bueso <dbueso@suse.de>
Subject: [PATCH] bluetooth: optimize barrier usage for Rmw atomics
Date: Wed, 29 Jan 2020 10:10:41 -0800 [thread overview]
Message-ID: <20200129181041.24853-1-dave@stgolabs.net> (raw)
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>
---
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
next reply other threads:[~2020-01-29 18:20 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-29 18:10 Davidlohr Bueso [this message]
2020-01-29 19:03 ` [PATCH] bluetooth: optimize barrier usage for Rmw atomics Marcel Holtmann
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