Revert "udp_tunnel: GRO optimizations"

Revert "udp_tunnel: use static call for GRO hooks when possible"
This reverts commit 311b36574ceaccfa3f91b74054a09cd4bb877702.

Revert "udp_tunnel: create a fastpath GRO lookup."
This reverts commit 8d4880db378350f8ed8969feea13bdc164564fc1.

There are multiple small issues with the series. In the interest
of unblocking the merge window let's opt for a revert.

Link: https://lore.kernel.org/cover.1742557254.git.pabeni@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

9 files changed, 2 insertions, 249 deletions

diff --git a/include/linux/udp.h b/include/linux/udp.h
index 895240177f4f..0807e21cfec9 100644
--- a/include/linux/udp.h
+++ b/include/linux/udp.h
@@ -101,13 +101,6 @@ struct udp_sock {
 
 	/* Cache friendly copy of sk->sk_peek_off >= 0 */
 	bool		peeking_with_offset;
-
-	/*
-	 * Accounting for the tunnel GRO fastpath.
-	 * Unprotected by compilers guard, as it uses space available in
-	 * the last UDP socket cacheline.
-	 */
-	struct hlist_node	tunnel_list;
 };
 
 #define udp_test_bit(nr, sk)			\
@@ -226,13 +219,4 @@ static inline void udp_allow_gso(struct sock *sk)
 
 #define IS_UDPLITE(__sk) (__sk->sk_protocol == IPPROTO_UDPLITE)
 
-static inline struct sock *udp_tunnel_sk(const struct net *net, bool is_ipv6)
-{
-#if IS_ENABLED(CONFIG_NET_UDP_TUNNEL)
-	return rcu_dereference(net->ipv4.udp_tunnel_gro[is_ipv6].sk);
-#else
-	return NULL;
-#endif
-}
-
 #endif	/* _LINUX_UDP_H */
diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index 6373e3f17da8..650b2dc9199f 100644
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -47,11 +47,6 @@ struct sysctl_fib_multipath_hash_seed {
 };
 #endif
 
-struct udp_tunnel_gro {
-	struct sock __rcu *sk;
-	struct hlist_head list;
-};
-
 struct netns_ipv4 {
 	/* Cacheline organization can be found documented in
 	 * Documentation/networking/net_cachelines/netns_ipv4_sysctl.rst.
@@ -90,11 +85,6 @@ struct netns_ipv4 {
 	struct inet_timewait_death_row tcp_death_row;
 	struct udp_table *udp_table;
 
-#if IS_ENABLED(CONFIG_NET_UDP_TUNNEL)
-	/* Not in a pernet subsys because need to be available at GRO stage */
-	struct udp_tunnel_gro udp_tunnel_gro[2];
-#endif
-
 #ifdef CONFIG_SYSCTL
 	struct ctl_table_header	*forw_hdr;
 	struct ctl_table_header	*frags_hdr;
@@ -287,5 +277,4 @@ struct netns_ipv4 {
 	struct hlist_head	*inet_addr_lst;
 	struct delayed_work	addr_chk_work;
 };
-
 #endif
diff --git a/include/net/udp.h b/include/net/udp.h
index a772510b2aa5..6e89520e100d 100644
--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -290,7 +290,6 @@ static inline void udp_lib_init_sock(struct sock *sk)
 	struct udp_sock *up = udp_sk(sk);
 
 	skb_queue_head_init(&up->reader_queue);
-	INIT_HLIST_NODE(&up->tunnel_list);
 	up->forward_threshold = sk->sk_rcvbuf >> 2;
 	set_bit(SOCK_CUSTOM_SOCKOPT, &sk->sk_socket->flags);
 }
diff --git a/include/net/udp_tunnel.h b/include/net/udp_tunnel.h
index a7b230867eb1..a93dc51f6323 100644
--- a/include/net/udp_tunnel.h
+++ b/include/net/udp_tunnel.h
@@ -203,28 +203,6 @@ static inline void udp_tunnel_encap_enable(struct sock *sk)
 	udp_encap_enable();
 }
 
-#if IS_ENABLED(CONFIG_NET_UDP_TUNNEL)
-void udp_tunnel_update_gro_lookup(struct net *net, struct sock *sk, bool add);
-void udp_tunnel_update_gro_rcv(struct sock *sk, bool add);
-#else
-static inline void udp_tunnel_update_gro_lookup(struct net *net,
-						struct sock *sk, bool add) {}
-static inline void udp_tunnel_update_gro_rcv(struct sock *sk, bool add) {}
-#endif
-
-static inline void udp_tunnel_cleanup_gro(struct sock *sk)
-{
-	struct udp_sock *up = udp_sk(sk);
-	struct net *net = sock_net(sk);
-
-	udp_tunnel_update_gro_rcv(sk, false);
-
-	if (!up->tunnel_list.pprev)
-		return;
-
-	udp_tunnel_update_gro_lookup(net, sk, false);
-}
-
 #define UDP_TUNNEL_NIC_MAX_TABLES	4
 
 enum udp_tunnel_nic_info_flags {
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index db606f7e4163..d0bffcfa56d8 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -2891,10 +2891,8 @@ void udp_destroy_sock(struct sock *sk)
 			if (encap_destroy)
 				encap_destroy(sk);
 		}
-		if (udp_test_bit(ENCAP_ENABLED, sk)) {
+		if (udp_test_bit(ENCAP_ENABLED, sk))
 			static_branch_dec(&udp_encap_needed_key);
-			udp_tunnel_cleanup_gro(sk);
-		}
 	}
 }
 
@@ -3806,15 +3804,6 @@ fallback:
 
 static int __net_init udp_pernet_init(struct net *net)
 {
-#if IS_ENABLED(CONFIG_NET_UDP_TUNNEL)
-	int i;
-
-	/* No tunnel is configured */
-	for (i = 0; i < ARRAY_SIZE(net->ipv4.udp_tunnel_gro); ++i) {
-		INIT_HLIST_HEAD(&net->ipv4.udp_tunnel_gro[i].list);
-		RCU_INIT_POINTER(net->ipv4.udp_tunnel_gro[i].sk, NULL);
-	}
-#endif
 	udp_sysctl_init(net);
 	udp_set_table(net);
 
diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
index 088aa8cb8ac0..2c0725583be3 100644
--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -12,164 +12,6 @@
 #include <net/udp.h>
 #include <net/protocol.h>
 #include <net/inet_common.h>
-#include <net/udp_tunnel.h>
-
-#if IS_ENABLED(CONFIG_NET_UDP_TUNNEL)
-
-/*
- * Dummy GRO tunnel callback, exists mainly to avoid dangling/NULL
- * values for the udp tunnel static call.
- */
-static struct sk_buff *dummy_gro_rcv(struct sock *sk,
-				     struct list_head *head,
-				     struct sk_buff *skb)
-{
-	NAPI_GRO_CB(skb)->flush = 1;
-	return NULL;
-}
-
-typedef struct sk_buff *(*udp_tunnel_gro_rcv_t)(struct sock *sk,
-						struct list_head *head,
-						struct sk_buff *skb);
-
-struct udp_tunnel_type_entry {
-	udp_tunnel_gro_rcv_t gro_receive;
-	refcount_t count;
-};
-
-#define UDP_MAX_TUNNEL_TYPES (IS_ENABLED(CONFIG_GENEVE) + \
-			      IS_ENABLED(CONFIG_VXLAN) * 2 + \
-			      IS_ENABLED(CONFIG_NET_FOU) * 2)
-
-DEFINE_STATIC_CALL(udp_tunnel_gro_rcv, dummy_gro_rcv);
-static DEFINE_STATIC_KEY_FALSE(udp_tunnel_static_call);
-static struct mutex udp_tunnel_gro_type_lock;
-static struct udp_tunnel_type_entry udp_tunnel_gro_types[UDP_MAX_TUNNEL_TYPES];
-static unsigned int udp_tunnel_gro_type_nr;
-static DEFINE_SPINLOCK(udp_tunnel_gro_lock);
-
-void udp_tunnel_update_gro_lookup(struct net *net, struct sock *sk, bool add)
-{
-	bool is_ipv6 = sk->sk_family == AF_INET6;
-	struct udp_sock *tup, *up = udp_sk(sk);
-	struct udp_tunnel_gro *udp_tunnel_gro;
-
-	spin_lock(&udp_tunnel_gro_lock);
-	udp_tunnel_gro = &net->ipv4.udp_tunnel_gro[is_ipv6];
-	if (add)
-		hlist_add_head(&up->tunnel_list, &udp_tunnel_gro->list);
-	else
-		hlist_del_init(&up->tunnel_list);
-
-	if (udp_tunnel_gro->list.first &&
-	    !udp_tunnel_gro->list.first->next) {
-		tup = hlist_entry(udp_tunnel_gro->list.first, struct udp_sock,
-				  tunnel_list);
-
-		rcu_assign_pointer(udp_tunnel_gro->sk, (struct sock *)tup);
-	} else {
-		RCU_INIT_POINTER(udp_tunnel_gro->sk, NULL);
-	}
-
-	spin_unlock(&udp_tunnel_gro_lock);
-}
-EXPORT_SYMBOL_GPL(udp_tunnel_update_gro_lookup);
-
-void udp_tunnel_update_gro_rcv(struct sock *sk, bool add)
-{
-	struct udp_tunnel_type_entry *cur = NULL;
-	struct udp_sock *up = udp_sk(sk);
-	int i, old_gro_type_nr;
-
-	if (!up->gro_receive)
-		return;
-
-	mutex_lock(&udp_tunnel_gro_type_lock);
-	for (i = 0; i < udp_tunnel_gro_type_nr; i++)
-		if (udp_tunnel_gro_types[i].gro_receive == up->gro_receive)
-			cur = &udp_tunnel_gro_types[i];
-
-	old_gro_type_nr = udp_tunnel_gro_type_nr;
-	if (add) {
-		/*
-		 * Update the matching entry, if found, or add a new one
-		 * if needed
-		 */
-		if (cur) {
-			refcount_inc(&cur->count);
-			goto out;
-		}
-
-		if (unlikely(udp_tunnel_gro_type_nr == UDP_MAX_TUNNEL_TYPES)) {
-			pr_err_once("Too many UDP tunnel types, please increase UDP_MAX_TUNNEL_TYPES\n");
-			/* Ensure static call will never be enabled */
-			udp_tunnel_gro_type_nr = UDP_MAX_TUNNEL_TYPES + 2;
-			goto out;
-		}
-
-		cur = &udp_tunnel_gro_types[udp_tunnel_gro_type_nr++];
-		refcount_set(&cur->count, 1);
-		cur->gro_receive = up->gro_receive;
-	} else {
-		/*
-		 * The stack cleanups only successfully added tunnel, the
-		 * lookup on removal should never fail.
-		 */
-		if (WARN_ON_ONCE(!cur))
-			goto out;
-
-		if (!refcount_dec_and_test(&cur->count))
-			goto out;
-
-		/* avoid gaps, so that the enable tunnel has always id 0 */
-		*cur = udp_tunnel_gro_types[--udp_tunnel_gro_type_nr];
-	}
-
-	if (udp_tunnel_gro_type_nr == 1) {
-		static_call_update(udp_tunnel_gro_rcv,
-				   udp_tunnel_gro_types[0].gro_receive);
-		static_branch_enable(&udp_tunnel_static_call);
-	} else if (old_gro_type_nr == 1) {
-		static_branch_disable(&udp_tunnel_static_call);
-		static_call_update(udp_tunnel_gro_rcv, dummy_gro_rcv);
-	}
-
-out:
-	mutex_unlock(&udp_tunnel_gro_type_lock);
-}
-EXPORT_SYMBOL_GPL(udp_tunnel_update_gro_rcv);
-
-static void udp_tunnel_gro_init(void)
-{
-	mutex_init(&udp_tunnel_gro_type_lock);
-}
-
-static struct sk_buff *udp_tunnel_gro_rcv(struct sock *sk,
-					  struct list_head *head,
-					  struct sk_buff *skb)
-{
-	if (static_branch_likely(&udp_tunnel_static_call)) {
-		if (unlikely(gro_recursion_inc_test(skb))) {
-			NAPI_GRO_CB(skb)->flush |= 1;
-			return NULL;
-		}
-		return static_call(udp_tunnel_gro_rcv)(sk, head, skb);
-	}
-	return call_gro_receive_sk(udp_sk(sk)->gro_receive, sk, head, skb);
-}
-
-#else
-
-static void udp_tunnel_gro_init(void) {}
-
-static struct sk_buff *udp_tunnel_gro_rcv(struct sock *sk,
-					  struct list_head *head,
-					  struct sk_buff *skb)
-{
-	return call_gro_receive_sk(udp_sk(sk)->gro_receive, sk, head, skb);
-}
-
-#endif
 
 static struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb,
 	netdev_features_t features,
@@ -780,7 +622,7 @@ struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
 
 	skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */
 	skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr));
-	pp = udp_tunnel_gro_rcv(sk, head, skb);
+	pp = call_gro_receive_sk(udp_sk(sk)->gro_receive, sk, head, skb);
 
 out:
 	skb_gro_flush_final(skb, pp, flush);
@@ -793,13 +635,8 @@ static struct sock *udp4_gro_lookup_skb(struct sk_buff *skb, __be16 sport,
 {
 	const struct iphdr *iph = skb_gro_network_header(skb);
 	struct net *net = dev_net_rcu(skb->dev);
-	struct sock *sk;
 	int iif, sdif;
 
-	sk = udp_tunnel_sk(net, false);
-	if (sk && dport == htons(sk->sk_num))
-		return sk;
-
 	inet_get_iif_sdif(skb, &iif, &sdif);
 
 	return __udp4_lib_lookup(net, iph->saddr, sport,
@@ -930,7 +767,5 @@ int __init udpv4_offload_init(void)
 			.gro_complete =	udp4_gro_complete,
 		},
 	};
-
-	udp_tunnel_gro_init();
 	return inet_add_offload(&net_hotdata.udpv4_offload, IPPROTO_UDP);
 }
diff --git a/net/ipv4/udp_tunnel_core.c b/net/ipv4/udp_tunnel_core.c
index c49fceea8313..619a53eb672d 100644
--- a/net/ipv4/udp_tunnel_core.c
+++ b/net/ipv4/udp_tunnel_core.c
@@ -58,15 +58,6 @@ error:
 }
 EXPORT_SYMBOL(udp_sock_create4);
 
-static bool sk_saddr_any(struct sock *sk)
-{
-#if IS_ENABLED(CONFIG_IPV6)
-	return ipv6_addr_any(&sk->sk_v6_rcv_saddr);
-#else
-	return !sk->sk_rcv_saddr;
-#endif
-}
-
 void setup_udp_tunnel_sock(struct net *net, struct socket *sock,
 			   struct udp_tunnel_sock_cfg *cfg)
 {
@@ -89,11 +80,6 @@ void setup_udp_tunnel_sock(struct net *net, struct socket *sock,
 	udp_sk(sk)->gro_complete = cfg->gro_complete;
 
 	udp_tunnel_encap_enable(sk);
-
-	udp_tunnel_update_gro_rcv(sock->sk, true);
-
-	if (!sk->sk_dport && !sk->sk_bound_dev_if && sk_saddr_any(sock->sk))
-		udp_tunnel_update_gro_lookup(net, sock->sk, true);
 }
 EXPORT_SYMBOL_GPL(setup_udp_tunnel_sock);
 
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 7317f8e053f1..024458ef163c 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -46,7 +46,6 @@
 #include <net/tcp_states.h>
 #include <net/ip6_checksum.h>
 #include <net/ip6_tunnel.h>
-#include <net/udp_tunnel.h>
 #include <net/xfrm.h>
 #include <net/inet_hashtables.h>
 #include <net/inet6_hashtables.h>
@@ -1826,7 +1825,6 @@ void udpv6_destroy_sock(struct sock *sk)
 		if (udp_test_bit(ENCAP_ENABLED, sk)) {
 			static_branch_dec(&udpv6_encap_needed_key);
 			udp_encap_disable();
-			udp_tunnel_cleanup_gro(sk);
 		}
 	}
 }
diff --git a/net/ipv6/udp_offload.c b/net/ipv6/udp_offload.c
index d8445ac1b2e4..404212dfc99a 100644
--- a/net/ipv6/udp_offload.c
+++ b/net/ipv6/udp_offload.c
@@ -118,13 +118,8 @@ static struct sock *udp6_gro_lookup_skb(struct sk_buff *skb, __be16 sport,
 {
 	const struct ipv6hdr *iph = skb_gro_network_header(skb);
 	struct net *net = dev_net_rcu(skb->dev);
-	struct sock *sk;
 	int iif, sdif;
 
-	sk = udp_tunnel_sk(net, true);
-	if (sk && dport == htons(sk->sk_num))
-		return sk;
-
 	inet6_get_iif_sdif(skb, &iif, &sdif);
 
 	return __udp6_lib_lookup(net, &iph->saddr, sport,