Commit e93abb84 authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

net/tcp_fastopen: remove tcp_fastopen_ctx_lock 



Remove the (per netns) spinlock in favor of xchg() atomic operations.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Acked-by: default avatarWei Wang <weiwan@google.com>
Link: https://lore.kernel.org/r/20210719101107.3203943-1-eric.dumazet@gmail.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent fef773fc

include/net/netns/ipv4.h

+0 −1
Original line number Diff line number Diff line
@@ -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;

net/ipv4/tcp_fastopen.c

+3 −14
Original line number Diff line number Diff line
@@ -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);

net/ipv4/tcp_ipv4.c

+0 −1
Original line number Diff line number Diff line
@@ -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);