bpf: sockmap: Simplify sock_map_init_proto

We can take advantage of the fact that both callers of
sock_map_init_proto are holding a RCU read lock, and
have verified that psock is valid.

Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200309111243.6982-7-lmb@cloudflare.com

diff --git a/net/core/sock_map.c b/net/core/sock_map.c
index cb240d8..edfdce1 100644 (file)
--- a/net/core/sock_map.c
+++ b/net/core/sock_map.c
@@ -141,28 +141,17 @@ static void sock_map_unref(struct sock *sk, void *link_raw)
        }
 }
 
-static int sock_map_init_proto(struct sock *sk)
+static int sock_map_init_proto(struct sock *sk, struct sk_psock *psock)
 {
-       struct sk_psock *psock;
        struct proto *prot;
 
        sock_owned_by_me(sk);
 
-       rcu_read_lock();
-       psock = sk_psock(sk);
-       if (unlikely(!psock)) {
-               rcu_read_unlock();
-               return -EINVAL;
-       }
-
        prot = tcp_bpf_get_proto(sk, psock);
-       if (IS_ERR(prot)) {
-               rcu_read_unlock();
+       if (IS_ERR(prot))
                return PTR_ERR(prot);
-       }
 
        sk_psock_update_proto(sk, psock, prot);
-       rcu_read_unlock();
        return 0;
 }
 
@@ -241,7 +230,7 @@ static int sock_map_link(struct bpf_map *map, struct sk_psock_progs *progs,
        if (msg_parser)
                psock_set_prog(&psock->progs.msg_parser, msg_parser);
 
-       ret = sock_map_init_proto(sk);
+       ret = sock_map_init_proto(sk, psock);
        if (ret < 0)
                goto out_drop;
 
@@ -286,7 +275,7 @@ static int sock_map_link_no_progs(struct bpf_map *map, struct sock *sk)
                        return -ENOMEM;
        }
 
-       ret = sock_map_init_proto(sk);
+       ret = sock_map_init_proto(sk, psock);
        if (ret < 0)
                sk_psock_put(sk, psock);
        return ret;