rfkill: fix double-mutex-locking

rfkill_toggle_radio is called from functions where
rfkill->mutex is already aquired.

Remove the lock from rfkill_toggle_radio() and add it to
the only calling function that calls it without the lock held.
Signed-off-by: Michael Buesch <mb@bu3sch.de>
Acked-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/rfkill/rfkill.c

@@ -60,11 +60,7 @@ static void rfkill_led_trigger(struct rfkill *rfkill,
 static int rfkill_toggle_radio(struct rfkill *rfkill,
 				enum rfkill_state state)
 {
-	int retval;
-
-	retval = mutex_lock_interruptible(&rfkill->mutex);
-	if (retval)
-		return retval;
+	int retval = 0;
 
 	if (state != rfkill->state) {
 		retval = rfkill->toggle_radio(rfkill->data, state);
@@ -74,7 +70,6 @@ static int rfkill_toggle_radio(struct rfkill *rfkill,
 		}
 	}
 
-	mutex_unlock(&rfkill->mutex);
 	return retval;
 }
 
@@ -158,12 +153,13 @@ static ssize_t rfkill_state_store(struct device *dev,
 	if (!capable(CAP_NET_ADMIN))
 		return -EPERM;
 
+	if (mutex_lock_interruptible(&rfkill->mutex))
+		return -ERESTARTSYS;
 	error = rfkill_toggle_radio(rfkill,
 			state ? RFKILL_STATE_ON : RFKILL_STATE_OFF);
-	if (error)
-		return error;
+	mutex_unlock(&rfkill->mutex);
 
-	return count;
+	return error ? error : count;
 }
 
 static ssize_t rfkill_claim_show(struct device *dev,