[IrDA]: Fix Rx/Tx path race.

From: G. Liakhovetski <gl@dsa-ac.de>

We need to switch to NRM _before_ sending the final packet otherwise
we might hit a race condition where we get the first packet from the
peer while we're still in LAP_XMIT_P.
Signed-off-by: NSamuel Ortiz <samuel@sortiz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/net/irda/irlap.h

@@ -289,4 +289,21 @@ static inline void irlap_clear_disconnect(struct irlap_cb *self)
 	self->disconnect_pending = FALSE;
 }
 
+/*
+ * Function irlap_next_state (self, state)
+ *
+ *    Switches state and provides debug information
+ *
+ */
+static inline void irlap_next_state(struct irlap_cb *self, IRLAP_STATE state)
+{
+	/*
+	if (!self || self->magic != LAP_MAGIC)
+		return;
+
+	IRDA_DEBUG(4, "next LAP state = %s\n", irlap_state[state]);
+	*/
+	self->state = state;
+}
+
 #endif

net/irda/irlap_event.c

@@ -316,23 +316,6 @@ void irlap_do_event(struct irlap_cb *self, IRLAP_EVENT event,
 	}
 }
 
-/*
- * Function irlap_next_state (self, state)
- *
- *    Switches state and provides debug information
- *
- */
-static inline void irlap_next_state(struct irlap_cb *self, IRLAP_STATE state)
-{
-	/*
-	if (!self || self->magic != LAP_MAGIC)
-		return;
-
-	IRDA_DEBUG(4, "next LAP state = %s\n", irlap_state[state]);
-	*/
-	self->state = state;
-}
-
 /*
  * Function irlap_state_ndm (event, skb, frame)
  *
@@ -1086,7 +1069,6 @@ static int irlap_state_xmit_p(struct irlap_cb *self, IRLAP_EVENT event,
 			} else {
 				/* Final packet of window */
 				irlap_send_data_primary_poll(self, skb);
-				irlap_next_state(self, LAP_NRM_P);
 
 				/*
 				 * Make sure state machine does not try to send

net/irda/irlap_frame.c

@@ -798,16 +798,19 @@ void irlap_send_data_primary_poll(struct irlap_cb *self, struct sk_buff *skb)
 		self->vs = (self->vs + 1) % 8;
 		self->ack_required = FALSE;
 
+		irlap_next_state(self, LAP_NRM_P);
 		irlap_send_i_frame(self, tx_skb, CMD_FRAME);
 	} else {
 		IRDA_DEBUG(4, "%s(), sending unreliable frame\n", __FUNCTION__);
 
 		if (self->ack_required) {
 			irlap_send_ui_frame(self, skb_get(skb), self->caddr, CMD_FRAME);
+			irlap_next_state(self, LAP_NRM_P);
 			irlap_send_rr_frame(self, CMD_FRAME);
 			self->ack_required = FALSE;
 		} else {
 			skb->data[1] |= PF_BIT;
+			irlap_next_state(self, LAP_NRM_P);
 			irlap_send_ui_frame(self, skb_get(skb), self->caddr, CMD_FRAME);
 		}
 	}