diff options
| author |   Eric Dumazet <edumazet@google.com> | 2022-04-05 16:35:38 -0700 |
|---|---|---|
| committer |   Jakub Kicinski <kuba@kernel.org> | 2022-04-06 12:05:41 -0700 |
| commit | 40570375356c874b1578e05c1dcc3ff7c1322dbe (patch) | |
| tree | 54c7a52bfdd4e302f877e93dc94adb09cfa3aac4 /net/ipv4/tcp_veno.c | |
| parent | ip6_tunnel: Remove duplicate assignments (diff) | |
| download | linux-dev-40570375356c874b1578e05c1dcc3ff7c1322dbe.tar.xz linux-dev-40570375356c874b1578e05c1dcc3ff7c1322dbe.zip | |
tcp: add accessors to read/set tp->snd_cwnd
We had various bugs over the years with code
breaking the assumption that tp->snd_cwnd is greater
than zero.
Lately, syzbot reported the WARN_ON_ONCE(!tp->prior_cwnd) added
in commit 8b8a321ff72c ("tcp: fix zero cwnd in tcp_cwnd_reduction")
can trigger, and without a repro we would have to spend
considerable time finding the bug.
Instead of complaining too late, we want to catch where
and when tp->snd_cwnd is set to an illegal value.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Suggested-by: Yuchung Cheng <ycheng@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Link: https://lore.kernel.org/r/20220405233538.947344-1-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/ipv4/tcp_veno.c')
| -rw-r--r-- | net/ipv4/tcp_veno.c | 24 |
1 files changed, 12 insertions, 12 deletions
diff --git a/net/ipv4/tcp_veno.c b/net/ipv4/tcp_veno.c index cd50a61c9976..366ff6f214b2 100644 --- a/net/ipv4/tcp_veno.c +++ b/net/ipv4/tcp_veno.c @@ -146,11 +146,11 @@ static void tcp_veno_cong_avoid(struct sock *sk, u32 ack, u32 acked) rtt = veno->minrtt; - target_cwnd = (u64)tp->snd_cwnd * veno->basertt; + target_cwnd = (u64)tcp_snd_cwnd(tp) * veno->basertt; target_cwnd <<= V_PARAM_SHIFT; do_div(target_cwnd, rtt); - veno->diff = (tp->snd_cwnd << V_PARAM_SHIFT) - target_cwnd; + veno->diff = (tcp_snd_cwnd(tp) << V_PARAM_SHIFT) - target_cwnd; if (tcp_in_slow_start(tp)) { /* Slow start. */ @@ -164,15 +164,15 @@ static void tcp_veno_cong_avoid(struct sock *sk, u32 ack, u32 acked) /* In the "non-congestive state", increase cwnd * every rtt. */ - tcp_cong_avoid_ai(tp, tp->snd_cwnd, acked); + tcp_cong_avoid_ai(tp, tcp_snd_cwnd(tp), acked); } else { /* In the "congestive state", increase cwnd * every other rtt. */ - if (tp->snd_cwnd_cnt >= tp->snd_cwnd) { + if (tp->snd_cwnd_cnt >= tcp_snd_cwnd(tp)) { if (veno->inc && - tp->snd_cwnd < tp->snd_cwnd_clamp) { - tp->snd_cwnd++; + tcp_snd_cwnd(tp) < tp->snd_cwnd_clamp) { + tcp_snd_cwnd_set(tp, tcp_snd_cwnd(tp) + 1); veno->inc = 0; } else veno->inc = 1; @@ -181,10 +181,10 @@ static void tcp_veno_cong_avoid(struct sock *sk, u32 ack, u32 acked) tp->snd_cwnd_cnt += acked; } done: - if (tp->snd_cwnd < 2) - tp->snd_cwnd = 2; - else if (tp->snd_cwnd > tp->snd_cwnd_clamp) - tp->snd_cwnd = tp->snd_cwnd_clamp; + if (tcp_snd_cwnd(tp) < 2) + tcp_snd_cwnd_set(tp, 2); + else if (tcp_snd_cwnd(tp) > tp->snd_cwnd_clamp) + tcp_snd_cwnd_set(tp, tp->snd_cwnd_clamp); } /* Wipe the slate clean for the next rtt. */ /* veno->cntrtt = 0; */ @@ -199,10 +199,10 @@ static u32 tcp_veno_ssthresh(struct sock *sk) if (veno->diff < beta) /* in "non-congestive state", cut cwnd by 1/5 */ - return max(tp->snd_cwnd * 4 / 5, 2U); + return max(tcp_snd_cwnd(tp) * 4 / 5, 2U); else /* in "congestive state", cut cwnd by 1/2 */ - return max(tp->snd_cwnd >> 1U, 2U); + return max(tcp_snd_cwnd(tp) >> 1U, 2U); } static struct tcp_congestion_ops tcp_veno __read_mostly = { |