From 5aac49378742a52bbe8af3d25bc51b487be7b17f Mon Sep 17 00:00:00 2001 From: Andrea Parri Date: Tue, 14 Aug 2018 20:41:06 +0200 Subject: Bluetooth: Remove unnecessary smp_mb__{before,after}_atomic The barriers are unneeded; wait_woken() and woken_wake_function() already provide us with the required synchronization: remove them and document that we're relying on the (implicit) synchronization provided by wait_woken() and woken_wake_function(). Signed-off-by: Andrea Parri Reviewed-by: Brian Norris Signed-off-by: Marcel Holtmann --- net/bluetooth/hidp/core.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) (limited to 'net/bluetooth/hidp') diff --git a/net/bluetooth/hidp/core.c b/net/bluetooth/hidp/core.c index 253975cce943..3734dc1788b4 100644 --- a/net/bluetooth/hidp/core.c +++ b/net/bluetooth/hidp/core.c @@ -1074,6 +1074,10 @@ static int hidp_session_start_sync(struct hidp_session *session) static void hidp_session_terminate(struct hidp_session *session) { atomic_inc(&session->terminate); + /* + * See the comment preceding the call to wait_woken() + * in hidp_session_run(). + */ wake_up_interruptible(&hidp_session_wq); } @@ -1193,8 +1197,6 @@ static void hidp_session_run(struct hidp_session *session) * thread is woken up by ->sk_state_changed(). */ - /* Ensure session->terminate is updated */ - smp_mb__before_atomic(); if (atomic_read(&session->terminate)) break; @@ -1228,14 +1230,15 @@ static void hidp_session_run(struct hidp_session *session) hidp_process_transmit(session, &session->ctrl_transmit, session->ctrl_sock); + /* + * wait_woken() performs the necessary memory barriers + * for us; see the header comment for this primitive. + */ wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); } remove_wait_queue(&hidp_session_wq, &wait); atomic_inc(&session->terminate); - - /* Ensure session->terminate is updated */ - smp_mb__after_atomic(); } static int hidp_session_wake_function(wait_queue_entry_t *wait, -- cgit v1.2.3