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authorSebastian Andrzej Siewior <bigeasy@linutronix.de>2024-06-20 15:21:56 +0200
committerJakub Kicinski <kuba@kernel.org>2024-06-25 01:41:22 +0200
commitebad6d0334793f16a16e5320182f665292a31e0c (patch)
tree5f9bc37dcc2190e3cb37cde94f9b84ad2e5b8d59 /net/ipv4
parentnet/tcp_sigpool: Use nested-BH locking for sigpool_scratch. (diff)
downloadlinux-ebad6d0334793f16a16e5320182f665292a31e0c.tar.xz
linux-ebad6d0334793f16a16e5320182f665292a31e0c.zip
net/ipv4: Use nested-BH locking for ipv4_tcp_sk.
ipv4_tcp_sk is a per-CPU variable and relies on disabled BH for its locking. Without per-CPU locking in local_bh_disable() on PREEMPT_RT this data structure requires explicit locking. Make a struct with a sock member (original ipv4_tcp_sk) and a local_lock_t and use local_lock_nested_bh() for locking. This change adds only lockdep coverage and does not alter the functional behaviour for !PREEMPT_RT. Cc: David Ahern <dsahern@kernel.org> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Link: https://patch.msgid.link/20240620132727.660738-7-bigeasy@linutronix.de Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/tcp_ipv4.c15
1 files changed, 11 insertions, 4 deletions
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 8e49d69279d5..fd17f25ff288 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -93,7 +93,9 @@ static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key,
struct inet_hashinfo tcp_hashinfo;
EXPORT_SYMBOL(tcp_hashinfo);
-static DEFINE_PER_CPU(struct sock *, ipv4_tcp_sk);
+static DEFINE_PER_CPU(struct sock_bh_locked, ipv4_tcp_sk) = {
+ .bh_lock = INIT_LOCAL_LOCK(bh_lock),
+};
static u32 tcp_v4_init_seq(const struct sk_buff *skb)
{
@@ -882,7 +884,9 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb,
arg.tos = ip_hdr(skb)->tos;
arg.uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);
local_bh_disable();
- ctl_sk = this_cpu_read(ipv4_tcp_sk);
+ local_lock_nested_bh(&ipv4_tcp_sk.bh_lock);
+ ctl_sk = this_cpu_read(ipv4_tcp_sk.sock);
+
sock_net_set(ctl_sk, net);
if (sk) {
ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
@@ -907,6 +911,7 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb,
sock_net_set(ctl_sk, &init_net);
__TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
__TCP_INC_STATS(net, TCP_MIB_OUTRSTS);
+ local_unlock_nested_bh(&ipv4_tcp_sk.bh_lock);
local_bh_enable();
#ifdef CONFIG_TCP_MD5SIG
@@ -1002,7 +1007,8 @@ static void tcp_v4_send_ack(const struct sock *sk,
arg.tos = tos;
arg.uid = sock_net_uid(net, sk_fullsock(sk) ? sk : NULL);
local_bh_disable();
- ctl_sk = this_cpu_read(ipv4_tcp_sk);
+ local_lock_nested_bh(&ipv4_tcp_sk.bh_lock);
+ ctl_sk = this_cpu_read(ipv4_tcp_sk.sock);
sock_net_set(ctl_sk, net);
ctl_sk->sk_mark = (sk->sk_state == TCP_TIME_WAIT) ?
inet_twsk(sk)->tw_mark : READ_ONCE(sk->sk_mark);
@@ -1017,6 +1023,7 @@ static void tcp_v4_send_ack(const struct sock *sk,
sock_net_set(ctl_sk, &init_net);
__TCP_INC_STATS(net, TCP_MIB_OUTSEGS);
+ local_unlock_nested_bh(&ipv4_tcp_sk.bh_lock);
local_bh_enable();
}
@@ -3615,7 +3622,7 @@ void __init tcp_v4_init(void)
sk->sk_clockid = CLOCK_MONOTONIC;
- per_cpu(ipv4_tcp_sk, cpu) = sk;
+ per_cpu(ipv4_tcp_sk.sock, cpu) = sk;
}
if (register_pernet_subsys(&tcp_sk_ops))
panic("Failed to create the TCP control socket.\n");