sctp: sctp_transport_lookup_process should rcu_read_unlock when transport is null

Prior to this patch, sctp_transport_lookup_process didn't rcu_read_unlock
when it failed to find a transport by sctp_addrs_lookup_transport.

This patch is to fix it by moving up rcu_read_unlock right before checking
transport and also to remove the out path.

Fixes: f659765ec7bb ("sctp: fix the issue sctp_diag uses lock_sock in rcu_read_lock")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index d5f4b4a8369bc64d8501be37d153e99dead88af5..318c6786d6539a301ac7b76d82a49a1af3818d10 100644 (file)
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -4472,18 +4472,17 @@ int sctp_transport_lookup_process(int (*cb)(struct sctp_transport *, void *),
                                  const union sctp_addr *paddr, void *p)
 {
        struct sctp_transport *transport;
-       int err = -ENOENT;
+       int err;
 
        rcu_read_lock();
        transport = sctp_addrs_lookup_transport(net, laddr, paddr);
+       rcu_read_unlock();
        if (!transport)
-               goto out;
+               return -ENOENT;
 
-       rcu_read_unlock();
        err = cb(transport, p);
        sctp_transport_put(transport);
 
-out:
        return err;
 }
 EXPORT_SYMBOL_GPL(sctp_transport_lookup_process);