mptcp: use _fast lock version in __mptcp_move_skbs

The function is short and won't sleep, so this can use the _fast version.

Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>

net/mptcp/protocol.c

@@ -1471,13 +1471,14 @@ static bool __mptcp_move_skbs(struct mptcp_sock *msk)
  __mptcp_flush_join_list(msk);
  do {
  struct sock *ssk = mptcp_subflow_recv_lookup(msk);
+ bool slowpath;
 
  if (!ssk)
  break;
 
- lock_sock(ssk);
+ slowpath = lock_sock_fast(ssk);
  done = __mptcp_move_skbs_from_subflow(msk, ssk, &moved);
- release_sock(ssk);
+ unlock_sock_fast(ssk, slowpath);
  } while (!done);
 
  if (mptcp_ofo_queue(msk) || moved > 0) {