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Bluetooth: Remove unnecessary smp_mb__{before,after}_atomic

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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 <andrea.parri@amarulasolutions.com>
Reviewed-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
This commit is contained in:
Andrea Parri 2018-08-14 20:41:06 +02:00 committed by Marcel Holtmann
parent 1042caa79e
commit 5aac493787
3 changed files with 20 additions and 14 deletions
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7
net/bluetooth/bnep/core.c
View file

@ -489,9 +489,6 @@ static int bnep_session(void *arg)
add_wait_queue(sk_sleep(sk), &wait);
while (1) {
/* Ensure session->terminate is updated */
smp_mb__before_atomic();
if (atomic_read(&s->terminate))
break;
/* RX */
@ -512,6 +509,10 @@ static int bnep_session(void *arg)
break;
netif_wake_queue(dev);
/*
* 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(sk_sleep(sk), &wait);

14
net/bluetooth/cmtp/core.c
View file

@ -288,9 +288,6 @@ static int cmtp_session(void *arg)
add_wait_queue(sk_sleep(sk), &wait);
while (1) {
/* Ensure session->terminate is updated */
smp_mb__before_atomic();
if (atomic_read(&session->terminate))
break;
if (sk->sk_state != BT_CONNECTED)
@ -306,6 +303,10 @@ static int cmtp_session(void *arg)
cmtp_process_transmit(session);
/*
* 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(sk_sleep(sk), &wait);
@ -431,9 +432,10 @@ int cmtp_del_connection(struct cmtp_conndel_req *req)
/* Stop session thread */
atomic_inc(&session->terminate);
/* Ensure session->terminate is updated */
smp_mb__after_atomic();
/*
* See the comment preceding the call to wait_woken()
* in cmtp_session().
*/
wake_up_interruptible(sk_sleep(session->sock->sk));
} else
err = -ENOENT;

13
net/bluetooth/hidp/core.c
View file

@ -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,