diff options
| author | Jason Xing <kerneljasonxing@gmail.com> | 2025-03-17 20:03:14 +0800 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-03-25 04:27:20 -0700 |
| commit | 9552f90835ef3552d0af327e48dc360717777d62 (patch) | |
| tree | d3520dc3d4e998663707372a6b6e95e190ea92f4 | |
| parent | f38805c5d26fe4af97837c10d58074a7496638bf (diff) | |
tcp: support TCP_DELACK_MAX_US for set/getsockopt use
Support adjusting/reading delayed ack max for socket level by using
set/getsockopt().
This option aligns with TCP_BPF_DELACK_MAX usage. Considering that bpf
option was implemented before this patch, so we need to use a standalone
new option for pure tcp set/getsockopt() use.
Add WRITE_ONCE/READ_ONCE() to prevent data-race if setsockopt()
happens to write one value to icsk_delack_max while icsk_delack_max is
being read.
Signed-off-by: Jason Xing <kerneljasonxing@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250317120314.41404-3-kerneljasonxing@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | include/uapi/linux/tcp.h | 1 | ||||
| -rw-r--r-- | net/ipv4/tcp.c | 13 | ||||
| -rw-r--r-- | net/ipv4/tcp_output.c | 2 |
3 files changed, 14 insertions, 2 deletions
diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h index a126b3860e63..dc8fdc80e16b 100644 --- a/include/uapi/linux/tcp.h +++ b/include/uapi/linux/tcp.h @@ -141,6 +141,7 @@ enum { #define TCP_IS_MPTCP 43 /* Is MPTCP being used? */ #define TCP_RTO_MAX_MS 44 /* max rto time in ms */ #define TCP_RTO_MIN_US 45 /* min rto time in us */ +#define TCP_DELACK_MAX_US 46 /* max delayed ack time in us */ #define TCP_REPAIR_ON 1 #define TCP_REPAIR_OFF 0 diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index a8a1370d642e..6edc441b3702 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -3353,7 +3353,7 @@ int tcp_disconnect(struct sock *sk, int flags) icsk->icsk_probes_tstamp = 0; icsk->icsk_rto = TCP_TIMEOUT_INIT; WRITE_ONCE(icsk->icsk_rto_min, TCP_RTO_MIN); - icsk->icsk_delack_max = TCP_DELACK_MAX; + WRITE_ONCE(icsk->icsk_delack_max, TCP_DELACK_MAX); tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; tcp_snd_cwnd_set(tp, TCP_INIT_CWND); tp->snd_cwnd_cnt = 0; @@ -3841,6 +3841,14 @@ int do_tcp_setsockopt(struct sock *sk, int level, int optname, WRITE_ONCE(inet_csk(sk)->icsk_rto_min, rto_min); return 0; } + case TCP_DELACK_MAX_US: { + int delack_max = usecs_to_jiffies(val); + + if (delack_max > TCP_DELACK_MAX || delack_max < TCP_TIMEOUT_MIN) + return -EINVAL; + WRITE_ONCE(inet_csk(sk)->icsk_delack_max, delack_max); + return 0; + } } sockopt_lock_sock(sk); @@ -4683,6 +4691,9 @@ zerocopy_rcv_out: case TCP_RTO_MIN_US: val = jiffies_to_usecs(READ_ONCE(inet_csk(sk)->icsk_rto_min)); break; + case TCP_DELACK_MAX_US: + val = jiffies_to_usecs(READ_ONCE(inet_csk(sk)->icsk_delack_max)); + break; default: return -ENOPROTOOPT; } diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index e0a4e5432399..9a6061017114 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -4179,7 +4179,7 @@ u32 tcp_delack_max(const struct sock *sk) { u32 delack_from_rto_min = max(tcp_rto_min(sk), 2) - 1; - return min(inet_csk(sk)->icsk_delack_max, delack_from_rto_min); + return min(READ_ONCE(inet_csk(sk)->icsk_delack_max), delack_from_rto_min); } /* Send out a delayed ack, the caller does the policy checking |