[TIPC]: Overhaul of socket locking logic

This patch modifies TIPC's socket code to follow the same approach
used by other protocols.  This change eliminates the need for a
mutex in the TIPC-specific portion of the socket protocol data
structure -- in its place, the standard Linux socket backlog queue
and associated locking routines are utilized.  These changes fix
a long-standing receive queue bug on SMP systems, and also enable
individual read and write threads to utilize a socket without
unnecessarily interfering with each other.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 24 insertions, 7 deletions

diff --git a/net/tipc/port.c b/net/tipc/port.c
index e2646a96935d..2f5806410c64 100644
--- a/net/tipc/port.c
+++ b/net/tipc/port.c
@@ -1240,6 +1240,28 @@ exit:
         return res;
 }
 
+/**
+ * tipc_disconnect_port - disconnect port from peer
+ *
+ * Port must be locked.
+ */
+
+int tipc_disconnect_port(struct tipc_port *tp_ptr)
+{
+        int res;
+
+        if (tp_ptr->connected) {
+                tp_ptr->connected = 0;
+                /* let timer expire on it's own to avoid deadlock! */
+                tipc_nodesub_unsubscribe(
+                        &((struct port *)tp_ptr)->subscription);
+                res = TIPC_OK;
+        } else {
+                res = -ENOTCONN;
+        }
+        return res;
+}
+
 /*
  * tipc_disconnect(): Disconnect port form peer.
  *                    This is a node local operation.
@@ -1248,17 +1270,12 @@ exit:
 int tipc_disconnect(u32 ref)
 {
         struct port *p_ptr;
-        int res = -ENOTCONN;
+        int res;
 
         p_ptr = tipc_port_lock(ref);
         if (!p_ptr)
                 return -EINVAL;
-        if (p_ptr->publ.connected) {
-                p_ptr->publ.connected = 0;
-                /* let timer expire on it's own to avoid deadlock! */
-                tipc_nodesub_unsubscribe(&p_ptr->subscription);
-                res = TIPC_OK;
-        }
+        res = tipc_disconnect_port((struct tipc_port *)p_ptr);
         tipc_port_unlock(p_ptr);
         return res;
 }