tipc: return early for non-blocking sockets at link congestion

Until now, in stream/mcast send() we pass the message to the link
layer even when the link is congested and add the socket to the
link's wakeup queue. This is unnecessary for non-blocking sockets.
If a socket is set to non-blocking and sends multicast with zero
back off time while receiving EAGAIN, we exhaust the memory.

In this commit, we return immediately at stream/mcast send() for
non-blocking sockets.

Acked-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 0 deletions

diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index f9f5f3c3dab5..adf3e6ecf61e 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -697,6 +697,9 @@ static int tipc_sendmcast(struct  socket *sock, struct tipc_name_seq *seq,
         uint mtu;
         int rc;
 
+        if (!timeo && tsk->link_cong)
+                return -ELINKCONG;
+
         msg_set_type(mhdr, TIPC_MCAST_MSG);
         msg_set_lookup_scope(mhdr, TIPC_CLUSTER_SCOPE);
         msg_set_destport(mhdr, 0);
@@ -1072,6 +1075,9 @@ static int __tipc_send_stream(struct socket *sock, struct msghdr *m, size_t dsz)
         }
 
         timeo = sock_sndtimeo(sk, m->msg_flags & MSG_DONTWAIT);
+        if (!timeo && tsk->link_cong)
+                return -ELINKCONG;
+
         dnode = tsk_peer_node(tsk);
         skb_queue_head_init(&pktchain);