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authorEric Dumazet <edumazet@google.com>2022-04-06 02:35:38 +0300
committerJakub Kicinski <kuba@kernel.org>2022-04-06 22:05:41 +0300
commit40570375356c874b1578e05c1dcc3ff7c1322dbe (patch)
tree54c7a52bfdd4e302f877e93dc94adb09cfa3aac4 /net/ipv4/tcp_htcp.c
parent487dc3ca60e3e420d54bcc613cb49e8e85f34569 (diff)
downloadlinux-40570375356c874b1578e05c1dcc3ff7c1322dbe.tar.xz
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_htcp.c')
-rw-r--r--net/ipv4/tcp_htcp.c10
1 files changed, 5 insertions, 5 deletions
diff --git a/net/ipv4/tcp_htcp.c b/net/ipv4/tcp_htcp.c
index 55adcfcf96fe..52b1f2665dfa 100644
--- a/net/ipv4/tcp_htcp.c
+++ b/net/ipv4/tcp_htcp.c
@@ -124,7 +124,7 @@ static void measure_achieved_throughput(struct sock *sk,
ca->packetcount += sample->pkts_acked;
- if (ca->packetcount >= tp->snd_cwnd - (ca->alpha >> 7 ? : 1) &&
+ if (ca->packetcount >= tcp_snd_cwnd(tp) - (ca->alpha >> 7 ? : 1) &&
now - ca->lasttime >= ca->minRTT &&
ca->minRTT > 0) {
__u32 cur_Bi = ca->packetcount * HZ / (now - ca->lasttime);
@@ -225,7 +225,7 @@ static u32 htcp_recalc_ssthresh(struct sock *sk)
const struct htcp *ca = inet_csk_ca(sk);
htcp_param_update(sk);
- return max((tp->snd_cwnd * ca->beta) >> 7, 2U);
+ return max((tcp_snd_cwnd(tp) * ca->beta) >> 7, 2U);
}
static void htcp_cong_avoid(struct sock *sk, u32 ack, u32 acked)
@@ -242,9 +242,9 @@ static void htcp_cong_avoid(struct sock *sk, u32 ack, u32 acked)
/* In dangerous area, increase slowly.
* In theory this is tp->snd_cwnd += alpha / tp->snd_cwnd
*/
- if ((tp->snd_cwnd_cnt * ca->alpha)>>7 >= tp->snd_cwnd) {
- if (tp->snd_cwnd < tp->snd_cwnd_clamp)
- tp->snd_cwnd++;
+ if ((tp->snd_cwnd_cnt * ca->alpha)>>7 >= tcp_snd_cwnd(tp)) {
+ if (tcp_snd_cwnd(tp) < tp->snd_cwnd_clamp)
+ tcp_snd_cwnd_set(tp, tcp_snd_cwnd(tp) + 1);
tp->snd_cwnd_cnt = 0;
htcp_alpha_update(ca);
} else