rfcomm, sched/wait: Fix broken wait construct

Peter Zijlstra · Ingo Molnar · commit eedf7e47daa0 · 2014-11-04T07:17:47.000+01:00
rfcomm_run() is a tad broken in that is has a nested wait loop. One
cannot rely on p-&gt;state for the outer wait because the inner wait will
overwrite it.

Fix this using the new wait_woken() facility.

Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Cc: Peter Hurley &lt;peter@hurleysoftware.com&gt;
Cc: Alexander Holler &lt;holler@ahsoftware.de&gt;
Cc: David S. Miller &lt;davem@davemloft.net&gt;
Cc: Gustavo Padovan &lt;gustavo@padovan.org&gt;
Cc: Joe Perches &lt;joe@perches.com&gt;
Cc: Johan Hedberg &lt;johan.hedberg@gmail.com&gt;
Cc: Libor Pechacek &lt;lpechacek@suse.cz&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Cc: Marcel Holtmann &lt;marcel@holtmann.org&gt;
Cc: Seung-Woo Kim &lt;sw0312.kim@samsung.com&gt;
Cc: Vignesh Raman &lt;Vignesh_Raman@mentor.com&gt;
Cc: linux-bluetooth@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
diff --git a/net/bluetooth/rfcomm/core.c b/net/bluetooth/rfcomm/core.c
@@ -101,11 +101,11 @@ static struct rfcomm_session *rfcomm_session_del(struct rfcomm_session *s);
 #define __get_rpn_stop_bits(line) (((line) >> 2) & 0x1)
 #define __get_rpn_parity(line)    (((line) >> 3) & 0x7)
 
+static DECLARE_WAIT_QUEUE_HEAD(rfcomm_wq);
+
 static void rfcomm_schedule(void)
 {
-	if (!rfcomm_thread)
-		return;
-	wake_up_process(rfcomm_thread);
+	wake_up_all(&rfcomm_wq);
 }
 
 /* ---- RFCOMM FCS computation ---- */
@@ -2086,24 +2086,22 @@ static void rfcomm_kill_listener(void)
 
 static int rfcomm_run(void *unused)
 {
+	DEFINE_WAIT_FUNC(wait, woken_wake_function);
 	BT_DBG("");
 
 	set_user_nice(current, -10);
 
 	rfcomm_add_listener(BDADDR_ANY);
 
-	while (1) {
-		set_current_state(TASK_INTERRUPTIBLE);
-
-		if (kthread_should_stop())
-			break;
+	add_wait_queue(&rfcomm_wq, &wait);
+	while (!kthread_should_stop()) {
 
 		/* Process stuff */
 		rfcomm_process_sessions();
 
-		schedule();
+		wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
 	}
-	__set_current_state(TASK_RUNNING);
+	remove_wait_queue(&rfcomm_wq, &wait);
 
 	rfcomm_kill_listener();
 
