[PATCH net] bpf: fix SO_MAX_PACING_RATE to support TCP internal pacing

[Eric Dumazet]

From: Yuchung Cheng <ych...@google.com>

If sch_fq packet scheduler is not used, TCP can fallback to
internal pacing, but this requires sk_pacing_status to
be properly set.

Fixes: 8c4b4c7e9ff0 ("bpf: Add setsockopt helper function to bpf")
Signed-off-by: Yuchung Cheng <ych...@google.com>
Signed-off-by: Eric Dumazet <eduma...@google.com>
Cc: Lawrence Brakmo <bra...@fb.com>
---
 net/core/filter.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/net/core/filter.c b/net/core/filter.c
index 
2b3b436ef5457bf44c99780d6dec0b5f403f005c..e2556131169145600f476dfb4f349906d32a31c1
 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -4119,6 +4119,10 @@ BPF_CALL_5(bpf_setsockopt, struct bpf_sock_ops_kern *, 
bpf_sock,
                        sk->sk_sndbuf = max_t(int, val * 2, SOCK_MIN_SNDBUF);
                        break;
                case SO_MAX_PACING_RATE: /* 32bit version */
+                       if (val != ~0U)
+                               cmpxchg(&sk->sk_pacing_status,
+                                       SK_PACING_NONE,
+                                       SK_PACING_NEEDED);
                        sk->sk_max_pacing_rate = (val == ~0U) ? ~0UL : val;
                        sk->sk_pacing_rate = min(sk->sk_pacing_rate,
                                                 sk->sk_max_pacing_rate);
-- 
2.20.1.321.g9e740568ce-goog