skb_splice_bits(): get rid of callback

since pipe_lock is the outermost now, we don't need to drop/regain
socket locks around the call of splice_to_pipe() from skb_splice_bits(),
which kills the need to have a socket-specific callback; we can just
call splice_to_pipe() and be done with that.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 8309687..145082e 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -2475,28 +2475,13 @@
 	return unix_stream_read_generic(&state);
 }
 
-static ssize_t skb_unix_socket_splice(struct sock *sk,
-				      struct pipe_inode_info *pipe,
-				      struct splice_pipe_desc *spd)
-{
-	int ret;
-	struct unix_sock *u = unix_sk(sk);
-
-	mutex_unlock(&u->iolock);
-	ret = splice_to_pipe(pipe, spd);
-	mutex_lock(&u->iolock);
-
-	return ret;
-}
-
 static int unix_stream_splice_actor(struct sk_buff *skb,
 				    int skip, int chunk,
 				    struct unix_stream_read_state *state)
 {
 	return skb_splice_bits(skb, state->socket->sk,
 			       UNIXCB(skb).consumed + skip,
-			       state->pipe, chunk, state->splice_flags,
-			       skb_unix_socket_splice);
+			       state->pipe, chunk, state->splice_flags);
 }
 
 static ssize_t unix_stream_splice_read(struct socket *sock,  loff_t *ppos,