From: Eric Dumazet <eric.dumazet@gmail.com>
To: "David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>
Cc: netdev <netdev@vger.kernel.org>,
Eric Dumazet <edumazet@google.com>,
Eric Dumazet <eric.dumazet@gmail.com>,
Wei Wang <weiwan@google.com>, Yuchung Cheng <ycheng@google.com>,
Neal Cardwell <ncardwell@google.com>
Subject: [PATCH net-next] net/tcp_fastopen: remove tcp_fastopen_ctx_lock
Date: Mon, 19 Jul 2021 03:11:07 -0700 [thread overview]
Message-ID: <20210719101107.3203943-1-eric.dumazet@gmail.com> (raw)
From: Eric Dumazet <edumazet@google.com>
Remove the (per netns) spinlock in favor of xchg() atomic operations.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Wei Wang <weiwan@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
---
include/net/netns/ipv4.h | 1 -
net/ipv4/tcp_fastopen.c | 17 +++--------------
net/ipv4/tcp_ipv4.c | 1 -
3 files changed, 3 insertions(+), 16 deletions(-)
diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index b8620519eace8191c76c41f37bd51ac0d3788bc2..2f65701a43c953bd3a9a9e3d491882cb7bb11859 100644
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -174,7 +174,6 @@ struct netns_ipv4 {
int sysctl_tcp_fastopen;
const struct tcp_congestion_ops __rcu *tcp_congestion_control;
struct tcp_fastopen_context __rcu *tcp_fastopen_ctx;
- spinlock_t tcp_fastopen_ctx_lock;
unsigned int sysctl_tcp_fastopen_blackhole_timeout;
atomic_t tfo_active_disable_times;
unsigned long tfo_active_disable_stamp;
diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c
index 47c32604d38fca960d2cd56f3588bfd2e390b789..1a9fbd5448a719bb5407a8d1e8fbfbe54f56f258 100644
--- a/net/ipv4/tcp_fastopen.c
+++ b/net/ipv4/tcp_fastopen.c
@@ -55,12 +55,7 @@ void tcp_fastopen_ctx_destroy(struct net *net)
{
struct tcp_fastopen_context *ctxt;
- spin_lock(&net->ipv4.tcp_fastopen_ctx_lock);
-
- ctxt = rcu_dereference_protected(net->ipv4.tcp_fastopen_ctx,
- lockdep_is_held(&net->ipv4.tcp_fastopen_ctx_lock));
- rcu_assign_pointer(net->ipv4.tcp_fastopen_ctx, NULL);
- spin_unlock(&net->ipv4.tcp_fastopen_ctx_lock);
+ ctxt = xchg((__force struct tcp_fastopen_context **)&net->ipv4.tcp_fastopen_ctx, NULL);
if (ctxt)
call_rcu(&ctxt->rcu, tcp_fastopen_ctx_free);
@@ -89,18 +84,12 @@ int tcp_fastopen_reset_cipher(struct net *net, struct sock *sk,
ctx->num = 1;
}
- spin_lock(&net->ipv4.tcp_fastopen_ctx_lock);
if (sk) {
q = &inet_csk(sk)->icsk_accept_queue.fastopenq;
- octx = rcu_dereference_protected(q->ctx,
- lockdep_is_held(&net->ipv4.tcp_fastopen_ctx_lock));
- rcu_assign_pointer(q->ctx, ctx);
+ octx = xchg((__force struct tcp_fastopen_context **)&q->ctx, ctx);
} else {
- octx = rcu_dereference_protected(net->ipv4.tcp_fastopen_ctx,
- lockdep_is_held(&net->ipv4.tcp_fastopen_ctx_lock));
- rcu_assign_pointer(net->ipv4.tcp_fastopen_ctx, ctx);
+ octx = xchg((__force struct tcp_fastopen_context **)&net->ipv4.tcp_fastopen_ctx, ctx);
}
- spin_unlock(&net->ipv4.tcp_fastopen_ctx_lock);
if (octx)
call_rcu(&octx->rcu, tcp_fastopen_ctx_free);
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index b9dc2d6197be8b8b03a4d052ad1c87987c7a62aa..e9321dd39cdbcb664843d4ada09a21685b93abb7 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -2964,7 +2964,6 @@ static int __net_init tcp_sk_init(struct net *net)
net->ipv4.sysctl_tcp_comp_sack_slack_ns = 100 * NSEC_PER_USEC;
net->ipv4.sysctl_tcp_comp_sack_nr = 44;
net->ipv4.sysctl_tcp_fastopen = TFO_CLIENT_ENABLE;
- spin_lock_init(&net->ipv4.tcp_fastopen_ctx_lock);
net->ipv4.sysctl_tcp_fastopen_blackhole_timeout = 60 * 60;
atomic_set(&net->ipv4.tfo_active_disable_times, 0);
--
2.32.0.402.g57bb445576-goog
next reply other threads:[~2021-07-19 10:11 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-19 10:11 Eric Dumazet [this message]
2021-07-19 15:46 ` [PATCH net-next] net/tcp_fastopen: remove tcp_fastopen_ctx_lock Wei Wang
2021-07-20 11:30 ` patchwork-bot+netdevbpf
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