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| author | Lorenz Bauer <lmb@cloudflare.com> | 2020-08-21 11:29:43 +0100 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2020-08-21 15:16:11 -0700 |
| commit | 7b219da43f94a3b4d5a8aa4cc52b75b34f0301ec (patch) | |
| tree | 9e8b69676747ae4417cb3110697a45ccd5898539 /net/ipv4/tcp_bpf.c | |
| parent | dca5612f8eb9d0cf1dc254eb2adff1f16a588a7d (diff) | |
| download | linux-7b219da43f94a3b4d5a8aa4cc52b75b34f0301ec.tar.gz linux-7b219da43f94a3b4d5a8aa4cc52b75b34f0301ec.tar.xz | |
net: sk_msg: Simplify sk_psock initialization
Initializing psock->sk_proto and other saved callbacks is only
done in sk_psock_update_proto, after sk_psock_init has returned.
The logic for this is difficult to follow, and needlessly complex.
Instead, initialize psock->sk_proto whenever we allocate a new
psock. Additionally, assert the following invariants:
* The SK has no ULP: ULP does it's own finagling of sk->sk_prot
* sk_user_data is unused: we need it to store sk_psock
Protect our access to sk_user_data with sk_callback_lock, which
is what other users like reuseport arrays, etc. do.
The result is that an sk_psock is always fully initialized, and
that psock->sk_proto is always the "original" struct proto.
The latter allows us to use psock->sk_proto when initializing
IPv6 TCP / UDP callbacks for sockmap.
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200821102948.21918-2-lmb@cloudflare.com
Diffstat (limited to 'net/ipv4/tcp_bpf.c')
| -rw-r--r-- | net/ipv4/tcp_bpf.c | 13 |
1 files changed, 5 insertions, 8 deletions
diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c index 7aa68f4aae6c..37f4cb2bba5c 100644 --- a/net/ipv4/tcp_bpf.c +++ b/net/ipv4/tcp_bpf.c @@ -567,10 +567,9 @@ static void tcp_bpf_rebuild_protos(struct proto prot[TCP_BPF_NUM_CFGS], prot[TCP_BPF_TX].sendpage = tcp_bpf_sendpage; } -static void tcp_bpf_check_v6_needs_rebuild(struct sock *sk, struct proto *ops) +static void tcp_bpf_check_v6_needs_rebuild(struct proto *ops) { - if (sk->sk_family == AF_INET6 && - unlikely(ops != smp_load_acquire(&tcpv6_prot_saved))) { + if (unlikely(ops != smp_load_acquire(&tcpv6_prot_saved))) { spin_lock_bh(&tcpv6_prot_lock); if (likely(ops != tcpv6_prot_saved)) { tcp_bpf_rebuild_protos(tcp_bpf_prots[TCP_BPF_IPV6], ops); @@ -603,13 +602,11 @@ struct proto *tcp_bpf_get_proto(struct sock *sk, struct sk_psock *psock) int family = sk->sk_family == AF_INET6 ? TCP_BPF_IPV6 : TCP_BPF_IPV4; int config = psock->progs.msg_parser ? TCP_BPF_TX : TCP_BPF_BASE; - if (!psock->sk_proto) { - struct proto *ops = READ_ONCE(sk->sk_prot); - - if (tcp_bpf_assert_proto_ops(ops)) + if (sk->sk_family == AF_INET6) { + if (tcp_bpf_assert_proto_ops(psock->sk_proto)) return ERR_PTR(-EINVAL); - tcp_bpf_check_v6_needs_rebuild(sk, ops); + tcp_bpf_check_v6_needs_rebuild(psock->sk_proto); } return &tcp_bpf_prots[family][config]; |