bpf: move event_output to const_size_or_zero for xdp/skb as well

Similar rationale as in a60dd35d2e39 ("bpf: change bpf_perf_event_output
arg5 type to ARG_CONST_SIZE_OR_ZERO"), change the type to CONST_SIZE_OR_ZERO
such that we can better deal with optimized code. No changes needed in
bpf_event_output() as it can also deal with 0 size entirely (e.g. as only
wake-up signal with empty frame in perf RB, or packet dumps w/o meta data
as another such possibility).

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/net/core/filter.c b/net/core/filter.c
index e517885..9b9b70d 100644 (file)
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2861,7 +2861,7 @@ static const struct bpf_func_proto bpf_skb_event_output_proto = {
        .arg2_type      = ARG_CONST_MAP_PTR,
        .arg3_type      = ARG_ANYTHING,
        .arg4_type      = ARG_PTR_TO_MEM,
-       .arg5_type      = ARG_CONST_SIZE,
+       .arg5_type      = ARG_CONST_SIZE_OR_ZERO,
 };
 
 static unsigned short bpf_tunnel_key_af(u64 flags)
@@ -3150,7 +3150,7 @@ static const struct bpf_func_proto bpf_xdp_event_output_proto = {
        .arg2_type      = ARG_CONST_MAP_PTR,
        .arg3_type      = ARG_ANYTHING,
        .arg4_type      = ARG_PTR_TO_MEM,
-       .arg5_type      = ARG_CONST_SIZE,
+       .arg5_type      = ARG_CONST_SIZE_OR_ZERO,
 };
 
 BPF_CALL_1(bpf_get_socket_cookie, struct sk_buff *, skb)