[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: Samuel Ortiz <samuel@sortiz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 20 insertions, 18 deletions

diff --git a/include/net/irda/irlap.h b/include/net/irda/irlap.h
index f0248fb8e196..a3d370efb903 100644
--- a/include/net/irda/irlap.h
+++ b/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
diff --git a/net/irda/irlap_event.c b/net/irda/irlap_event.c
index 0b02073ffdf3..71c805506933 100644
--- a/net/irda/irlap_event.c
+++ b/net/irda/irlap_event.c
@@ -317,23 +317,6 @@ 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)
  *
  *    NDM (Normal Disconnected Mode) state
@@ -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
diff --git a/net/irda/irlap_frame.c b/net/irda/irlap_frame.c
index 3c5a68e36414..3013c49ab975 100644
--- a/net/irda/irlap_frame.c
+++ b/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);
                 }
         }