[PATCH net-next 08/18] netfilter: nf_dup_netdev: Move the recursion counter struct netdev_xmit.
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: 2025-03-09 14:47:11
Also in:
linux-rt-devel, netfilter-devel
Subsystem:
netfilter, networking drivers, networking [general], the rest · Maintainers:
Pablo Neira Ayuso, Florian Westphal, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
nf_dup_skb_recursion 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. Move nf_dup_skb_recursion to struct netdev_xmit, provide wrappers. Cc: Pablo Neira Ayuso <pablo@netfilter.org> Cc: Jozsef Kadlecsik <redacted> Cc: netfilter-devel@vger.kernel.org Cc: coreteam@netfilter.org Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- include/linux/netdevice_xmit.h | 3 +++ net/netfilter/nf_dup_netdev.c | 22 ++++++++++++++++++---- 2 files changed, 21 insertions(+), 4 deletions(-)
diff --git a/include/linux/netdevice_xmit.h b/include/linux/netdevice_xmit.h
index 38325e0702968..3bbbc1a9860a3 100644
--- a/include/linux/netdevice_xmit.h
+++ b/include/linux/netdevice_xmit.h@@ -8,6 +8,9 @@ struct netdev_xmit { #ifdef CONFIG_NET_EGRESS u8 skip_txqueue; #endif +#if IS_ENABLED(CONFIG_NF_DUP_NETDEV) + u8 nf_dup_skb_recursion; +#endif }; #endif
diff --git a/net/netfilter/nf_dup_netdev.c b/net/netfilter/nf_dup_netdev.c
index a8e2425e43b0d..fab8b9011098f 100644
--- a/net/netfilter/nf_dup_netdev.c
+++ b/net/netfilter/nf_dup_netdev.c@@ -15,12 +15,26 @@ #define NF_RECURSION_LIMIT 2 -static DEFINE_PER_CPU(u8, nf_dup_skb_recursion); +#ifndef CONFIG_PREEMPT_RT +static u8 *nf_get_nf_dup_skb_recursion(void) +{ + return this_cpu_ptr(&softnet_data.xmit.nf_dup_skb_recursion); +} +#else + +static u8 *nf_get_nf_dup_skb_recursion(void) +{ + return ¤t->net_xmit.nf_dup_skb_recursion; +} + +#endif static void nf_do_netdev_egress(struct sk_buff *skb, struct net_device *dev, enum nf_dev_hooks hook) { - if (__this_cpu_read(nf_dup_skb_recursion) > NF_RECURSION_LIMIT) + u8 *nf_dup_skb_recursion = nf_get_nf_dup_skb_recursion(); + + if (*nf_dup_skb_recursion > NF_RECURSION_LIMIT) goto err; if (hook == NF_NETDEV_INGRESS && skb_mac_header_was_set(skb)) {
@@ -32,9 +46,9 @@ static void nf_do_netdev_egress(struct sk_buff *skb, struct net_device *dev, skb->dev = dev; skb_clear_tstamp(skb); - __this_cpu_inc(nf_dup_skb_recursion); + (*nf_dup_skb_recursion)++; dev_queue_xmit(skb); - __this_cpu_dec(nf_dup_skb_recursion); + (*nf_dup_skb_recursion)--; return; err: kfree_skb(skb);
--
2.47.2