| Message ID | b65c13770225f4a655657373f5ad90bcef3f57c9.1741632298.git.pabeni@redhat.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | udp_tunnel: GRO optimizations | expand |
Paolo Abeni wrote: > It's quite common to have a single UDP tunnel type active in the > whole system. In such a case we can replace the indirect call for > the UDP tunnel GRO callback with a static call. > > Add the related accounting in the control path and switch to static > call when possible. To keep the code simple use a static array for > the registered tunnel types, and size such array based on the kernel > config. > > Signed-off-by: Paolo Abeni <pabeni@redhat.com> > --- > v2 -> v3: > - avoid unneeded checks in udp_tunnel_update_gro_rcv() > > v1 -> v2: > - fix UDP_TUNNEL=n build > --- > include/net/udp_tunnel.h | 4 ++ > net/ipv4/udp_offload.c | 137 ++++++++++++++++++++++++++++++++++++- > net/ipv4/udp_tunnel_core.c | 2 + > 3 files changed, 142 insertions(+), 1 deletion(-) > > diff --git a/include/net/udp_tunnel.h b/include/net/udp_tunnel.h > index eda0f3e2f65fa..a7b230867eb14 100644 > --- a/include/net/udp_tunnel.h > +++ b/include/net/udp_tunnel.h > @@ -205,9 +205,11 @@ static inline void udp_tunnel_encap_enable(struct sock *sk) > > #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) > @@ -215,6 +217,8 @@ 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; > > diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c > index 054d4d4a8927f..500b2a20053cd 100644 > --- a/net/ipv4/udp_offload.c > +++ b/net/ipv4/udp_offload.c > @@ -15,6 +15,39 @@ > #include <net/udp_tunnel.h> > > #if IS_ENABLED(CONFIG_NET_UDP_TUNNEL) > + > +/* > + * Dummy GRO tunnel callback; should never be invoked, 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) > +{ > + WARN_ON_ONCE(1); > + 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_FOE) * 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) > @@ -43,6 +76,106 @@ void udp_tunnel_update_gro_lookup(struct net *net, struct sock *sk, bool add) > 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, *avail = 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_MAX_TUNNEL_TYPES; i++) { > + if (!refcount_read(&udp_tunnel_gro_types[i].count)) Optionally: && !avail, to fill the list from the front. And on delete avoid gaps. For instance, like __fanout_link/__fanout_unlink. Can stop sooner then. And list length is then implicit as i once found the first [i].count == zero. Then again, this list is always short. I can imagine you prefer to leave as is. > + avail = &udp_tunnel_gro_types[i]; > + else 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(!avail)) { > + 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; > + } > + > + refcount_set(&avail->count, 1); > + avail->gro_receive = up->gro_receive; > + udp_tunnel_gro_type_nr++; > + } 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; > + udp_tunnel_gro_type_nr--; > + } > + > + if (udp_tunnel_gro_type_nr == 1) { > + for (i = 0; i < UDP_MAX_TUNNEL_TYPES; i++) { > + cur = &udp_tunnel_gro_types[i]; > + if (refcount_read(&cur->count)) { > + static_call_update(udp_tunnel_gro_rcv, > + cur->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); These operations must not be reorderd, or dummy_gro_rcv might get hit. If static calls are not configured, the last call is just a WRITE_ONCE. Similar for static_branch_disable if !CONFIG_JUMP_LABEL. > + } > + > +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, > @@ -654,7 +787,7 @@ 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 = call_gro_receive_sk(udp_sk(sk)->gro_receive, sk, head, skb); > + pp = udp_tunnel_gro_rcv(sk, head, skb); > > out: > skb_gro_flush_final(skb, pp, flush); > @@ -804,5 +937,7 @@ 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 b5695826e57ad..c49fceea83139 100644 > --- a/net/ipv4/udp_tunnel_core.c > +++ b/net/ipv4/udp_tunnel_core.c > @@ -90,6 +90,8 @@ void setup_udp_tunnel_sock(struct net *net, struct socket *sock, > > 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); > } > -- > 2.48.1 >
From: Paolo Abeni <pabeni@redhat.com> Date: Mon, 10 Mar 2025 20:09:49 +0100 > diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c > index 054d4d4a8927f..500b2a20053cd 100644 > --- a/net/ipv4/udp_offload.c > +++ b/net/ipv4/udp_offload.c > @@ -15,6 +15,39 @@ > #include <net/udp_tunnel.h> > > #if IS_ENABLED(CONFIG_NET_UDP_TUNNEL) > + > +/* > + * Dummy GRO tunnel callback; should never be invoked, 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) > +{ > + WARN_ON_ONCE(1); > + 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_FOE) * 2) I guess this is CONFIG_NET_FOU ?
On 3/11/25 3:51 AM, Willem de Bruijn wrote: > Paolo Abeni wrote: [...] >> +void udp_tunnel_update_gro_rcv(struct sock *sk, bool add) >> +{ >> + struct udp_tunnel_type_entry *cur = NULL, *avail = 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_MAX_TUNNEL_TYPES; i++) { >> + if (!refcount_read(&udp_tunnel_gro_types[i].count)) > > Optionally: && !avail, to fill the list from the front. And on delete > avoid gaps. For instance, like __fanout_link/__fanout_unlink. > > Can stop sooner then. And list length is then implicit as i once found > the first [i].count == zero. > > Then again, this list is always short. I can imagine you prefer to > leave as is. I avoided optimizations for this slow path, to keep the code simpler. Thinking again about it, avoiding gaps will simplify/cleanup the code a bit (no need to lookup the enabled tunnel on deletion and to use `avail` on addition), so I'll do it. Note that I'll still need to explicitly track the number of enabled tunnel types, as an easy way to disable the static call in the unlikely udp_tunnel_gro_type_nr == UDP_MAX_TUNNEL_TYPES event. [...] >> + if (udp_tunnel_gro_type_nr == 1) { >> + for (i = 0; i < UDP_MAX_TUNNEL_TYPES; i++) { >> + cur = &udp_tunnel_gro_types[i]; >> + if (refcount_read(&cur->count)) { >> + static_call_update(udp_tunnel_gro_rcv, >> + cur->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); > > These operations must not be reorderd, or dummy_gro_rcv might get hit. > > If static calls are not configured, the last call is just a > WRITE_ONCE. Similar for static_branch_disable if !CONFIG_JUMP_LABEL. When both construct are disabled, I think a wmb/rmb pair would be needed to ensure no reordering, and that in turn looks overkill. I think it would be better just drop the WARN_ONCE in dummy_gro_rcv(). /P
Paolo Abeni wrote: > On 3/11/25 3:51 AM, Willem de Bruijn wrote: > > Paolo Abeni wrote: > [...] > >> +void udp_tunnel_update_gro_rcv(struct sock *sk, bool add) > >> +{ > >> + struct udp_tunnel_type_entry *cur = NULL, *avail = 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_MAX_TUNNEL_TYPES; i++) { > >> + if (!refcount_read(&udp_tunnel_gro_types[i].count)) > > > > Optionally: && !avail, to fill the list from the front. And on delete > > avoid gaps. For instance, like __fanout_link/__fanout_unlink. > > > > Can stop sooner then. And list length is then implicit as i once found > > the first [i].count == zero. > > > > Then again, this list is always short. I can imagine you prefer to > > leave as is. > > I avoided optimizations for this slow path, to keep the code simpler. > Thinking again about it, avoiding gaps will simplify/cleanup the code a > bit (no need to lookup the enabled tunnel on deletion and to use `avail` > on addition), so I'll do it. > > Note that I'll still need to explicitly track the number of enabled > tunnel types, as an easy way to disable the static call in the unlikely > udp_tunnel_gro_type_nr == UDP_MAX_TUNNEL_TYPES event. > > [...] > >> + if (udp_tunnel_gro_type_nr == 1) { > >> + for (i = 0; i < UDP_MAX_TUNNEL_TYPES; i++) { > >> + cur = &udp_tunnel_gro_types[i]; > >> + if (refcount_read(&cur->count)) { > >> + static_call_update(udp_tunnel_gro_rcv, > >> + cur->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); > > > > These operations must not be reorderd, or dummy_gro_rcv might get hit. > > > > If static calls are not configured, the last call is just a > > WRITE_ONCE. Similar for static_branch_disable if !CONFIG_JUMP_LABEL. > > When both construct are disabled, I think a wmb/rmb pair would be needed > to ensure no reordering, and that in turn looks overkill. I think it > would be better just drop the WARN_ONCE in dummy_gro_rcv(). SGTM, thanks.
diff --git a/include/net/udp_tunnel.h b/include/net/udp_tunnel.h index eda0f3e2f65fa..a7b230867eb14 100644 --- a/include/net/udp_tunnel.h +++ b/include/net/udp_tunnel.h @@ -205,9 +205,11 @@ static inline void udp_tunnel_encap_enable(struct sock *sk) #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) @@ -215,6 +217,8 @@ 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; diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c index 054d4d4a8927f..500b2a20053cd 100644 --- a/net/ipv4/udp_offload.c +++ b/net/ipv4/udp_offload.c @@ -15,6 +15,39 @@ #include <net/udp_tunnel.h> #if IS_ENABLED(CONFIG_NET_UDP_TUNNEL) + +/* + * Dummy GRO tunnel callback; should never be invoked, 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) +{ + WARN_ON_ONCE(1); + 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_FOE) * 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) @@ -43,6 +76,106 @@ void udp_tunnel_update_gro_lookup(struct net *net, struct sock *sk, bool add) 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, *avail = 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_MAX_TUNNEL_TYPES; i++) { + if (!refcount_read(&udp_tunnel_gro_types[i].count)) + avail = &udp_tunnel_gro_types[i]; + else 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(!avail)) { + 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; + } + + refcount_set(&avail->count, 1); + avail->gro_receive = up->gro_receive; + udp_tunnel_gro_type_nr++; + } 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; + udp_tunnel_gro_type_nr--; + } + + if (udp_tunnel_gro_type_nr == 1) { + for (i = 0; i < UDP_MAX_TUNNEL_TYPES; i++) { + cur = &udp_tunnel_gro_types[i]; + if (refcount_read(&cur->count)) { + static_call_update(udp_tunnel_gro_rcv, + cur->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, @@ -654,7 +787,7 @@ 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 = call_gro_receive_sk(udp_sk(sk)->gro_receive, sk, head, skb); + pp = udp_tunnel_gro_rcv(sk, head, skb); out: skb_gro_flush_final(skb, pp, flush); @@ -804,5 +937,7 @@ 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 b5695826e57ad..c49fceea83139 100644 --- a/net/ipv4/udp_tunnel_core.c +++ b/net/ipv4/udp_tunnel_core.c @@ -90,6 +90,8 @@ void setup_udp_tunnel_sock(struct net *net, struct socket *sock, 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); }
It's quite common to have a single UDP tunnel type active in the whole system. In such a case we can replace the indirect call for the UDP tunnel GRO callback with a static call. Add the related accounting in the control path and switch to static call when possible. To keep the code simple use a static array for the registered tunnel types, and size such array based on the kernel config. Signed-off-by: Paolo Abeni <pabeni@redhat.com> --- v2 -> v3: - avoid unneeded checks in udp_tunnel_update_gro_rcv() v1 -> v2: - fix UDP_TUNNEL=n build --- include/net/udp_tunnel.h | 4 ++ net/ipv4/udp_offload.c | 137 ++++++++++++++++++++++++++++++++++++- net/ipv4/udp_tunnel_core.c | 2 + 3 files changed, 142 insertions(+), 1 deletion(-)