irda: replace current->state by set_current_state()

Use helper functions to access current->state.
Direct assignments are prone to races and therefore buggy.

current->state = TASK_RUNNING can be replaced by __set_current_state()

Thanks to Peter Zijlstra for the exact definition of the problem.
Suggested-By: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/irda/ircomm/ircomm_tty.c

@@ -811,7 +811,7 @@ static void ircomm_tty_wait_until_sent(struct tty_struct *tty, int timeout)
 			break;
 	}
 	spin_unlock_irqrestore(&self->spinlock, flags);
-	current->state = TASK_RUNNING;
+	__set_current_state(TASK_RUNNING);
 }
 
 /*

net/irda/irnet/irnet_ppp.c

@@ -305,7 +305,7 @@ irnet_ctrl_read(irnet_socket *	ap,
 
   /* Put ourselves on the wait queue to be woken up */
   add_wait_queue(&irnet_events.rwait, &wait);
-  current->state = TASK_INTERRUPTIBLE;
+  set_current_state(TASK_INTERRUPTIBLE);
   for(;;)
     {
       /* If there is unread events */
@@ -321,7 +321,7 @@ irnet_ctrl_read(irnet_socket *	ap,
       /* Yield and wait to be woken up */
       schedule();
     }
-  current->state = TASK_RUNNING;
+  __set_current_state(TASK_RUNNING);
   remove_wait_queue(&irnet_events.rwait, &wait);
 
   /* Did we got it ? */