On Wed, Feb 27, 2019 at 11:16 AM Stanislav Fomichev <sdf@xxxxxxxxxx> wrote:
>
> Older GCC (<4.8) isn't smart enough to optimize !__builtin_constant_p()
> branch in bpf_htons.
>
> I recently fixed it for pkt_v4 and pkt_v6 in commit a0517a0f7ef23
> ("selftests/bpf: use __bpf_constant_htons in test_prog.c"), but later
> added another bunch of bpf_htons in commit bf0f0fd939451 ("selftests/bpf:
> add simple BPF_PROG_TEST_RUN examples for flow dissector").
>
> Fixes: bf0f0fd939451 ("selftests/bpf: add simple BPF_PROG_TEST_RUN examples for flow dissector")
>
> Signed-off-by: Stanislav Fomichev <sdf@xxxxxxxxxx>
Acked-by: Song Liu <songliubraving@xxxxxx>
> ---
> tools/testing/selftests/bpf/test_progs.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c
> index c59d2e015d16..87cde42559f7 100644
> --- a/tools/testing/selftests/bpf/test_progs.c
> +++ b/tools/testing/selftests/bpf/test_progs.c
> @@ -1954,7 +1954,7 @@ static struct bpf_flow_keys pkt_v4_flow_keys = {
> .thoff = sizeof(struct iphdr),
> .addr_proto = ETH_P_IP,
> .ip_proto = IPPROTO_TCP,
> - .n_proto = bpf_htons(ETH_P_IP),
> + .n_proto = __bpf_constant_htons(ETH_P_IP),
> };
>
> static struct bpf_flow_keys pkt_v6_flow_keys = {
> @@ -1962,7 +1962,7 @@ static struct bpf_flow_keys pkt_v6_flow_keys = {
> .thoff = sizeof(struct ipv6hdr),
> .addr_proto = ETH_P_IPV6,
> .ip_proto = IPPROTO_TCP,
> - .n_proto = bpf_htons(ETH_P_IPV6),
> + .n_proto = __bpf_constant_htons(ETH_P_IPV6),
> };
>
> static void test_flow_dissector(void)
> --
> 2.21.0.rc2.261.ga7da99ff1b-goog
>
