rxrpc: Use RCU to access a peer's service connection tree

[cascardo/linux.git] / net / rxrpc / input.c

diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c
index c243647..991a20d 100644 (file)
--- a/net/rxrpc/input.c
+++ b/net/rxrpc/input.c
@@ -575,13 +575,13 @@ done:
  * post connection-level events to the connection
  * - this includes challenges, responses and some aborts
  */
-static void rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
+static bool rxrpc_post_packet_to_conn(struct rxrpc_connection *conn,
                                      struct sk_buff *skb)
 {
        _enter("%p,%p", conn, skb);
 
        skb_queue_tail(&conn->rx_queue, skb);
-       rxrpc_queue_conn(conn);
+       return rxrpc_queue_conn(conn);
 }
 
 /*
@@ -636,6 +636,7 @@ int rxrpc_extract_header(struct rxrpc_skb_priv *sp, struct sk_buff *skb)
  */
 void rxrpc_data_ready(struct sock *sk)
 {
+       struct rxrpc_connection *conn;
        struct rxrpc_skb_priv *sp;
        struct rxrpc_local *local = sk->sk_user_data;
        struct sk_buff *skb;
@@ -699,36 +700,37 @@ void rxrpc_data_ready(struct sock *sk)
            (sp->hdr.callNumber == 0 || sp->hdr.seq == 0))
                goto bad_message;
 
-       if (sp->hdr.callNumber == 0) {
-               /* This is a connection-level packet. These should be
-                * fairly rare, so the extra overhead of looking them up the
-                * old-fashioned way doesn't really hurt */
-               struct rxrpc_connection *conn;
-
-               rcu_read_lock();
-               conn = rxrpc_find_connection(local, skb);
-               rcu_read_unlock();
-               if (!conn)
-                       goto cant_route_call;
+       rcu_read_lock();
+
+retry_find_conn:
+       conn = rxrpc_find_connection_rcu(local, skb);
+       if (!conn)
+               goto cant_route_call;
 
+       if (sp->hdr.callNumber == 0) {
+               /* Connection-level packet */
                _debug("CONN %p {%d}", conn, conn->debug_id);
-               rxrpc_post_packet_to_conn(conn, skb);
-               rxrpc_put_connection(conn);
+               if (!rxrpc_post_packet_to_conn(conn, skb))
+                       goto retry_find_conn;
        } else {
-               struct rxrpc_call *call;
+               /* Call-bound packets are routed by connection channel. */
+               unsigned int channel = sp->hdr.cid & RXRPC_CHANNELMASK;
+               struct rxrpc_channel *chan = &conn->channels[channel];
+               struct rxrpc_call *call = rcu_dereference(chan->call);
 
-               call = rxrpc_find_call_hash(&sp->hdr, local,
-                                           AF_INET, &ip_hdr(skb)->saddr);
-               if (call)
-                       rxrpc_post_packet_to_call(call, skb);
-               else
+               if (!call || atomic_read(&call->usage) == 0)
                        goto cant_route_call;
+
+               rxrpc_post_packet_to_call(call, skb);
        }
 
+       rcu_read_unlock();
 out:
        return;
 
 cant_route_call:
+       rcu_read_unlock();
+
        _debug("can't route call");
        if (sp->hdr.flags & RXRPC_CLIENT_INITIATED &&
            sp->hdr.type == RXRPC_PACKET_TYPE_DATA) {