net/ipv4: Update ip_tunnel_metadata_cnt static key to modern api

No changes in refcount semantics -- key init is false; replace

static_key_slow_inc|dec with static_branch_inc|dec
static_key_false with static_branch_unlikely

Signed-off-by: Davidlohr Bueso <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/net/ip_tunnels.h

···
 	return (struct ip_tunnel_info *)lwtstate->data;
 }
 
-extern struct static_key ip_tunnel_metadata_cnt;
+DECLARE_STATIC_KEY_FALSE(ip_tunnel_metadata_cnt);
 
 /* Returns > 0 if metadata should be collected */
 static inline int ip_tunnel_collect_metadata(void)
 {
-	return static_key_false(&ip_tunnel_metadata_cnt);
+	return static_branch_unlikely(&ip_tunnel_metadata_cnt);
 }
 
 void __init ip_tunnel_core_init(void);

net/ipv4/ip_tunnel_core.c

···
 	lwtunnel_encap_add_ops(&ip6_tun_lwt_ops, LWTUNNEL_ENCAP_IP6);
 }
 
-struct static_key ip_tunnel_metadata_cnt = STATIC_KEY_INIT_FALSE;
+DEFINE_STATIC_KEY_FALSE(ip_tunnel_metadata_cnt);
 EXPORT_SYMBOL(ip_tunnel_metadata_cnt);
 
 void ip_tunnel_need_metadata(void)
 {
-	static_key_slow_inc(&ip_tunnel_metadata_cnt);
+	static_branch_inc(&ip_tunnel_metadata_cnt);
 }
 EXPORT_SYMBOL_GPL(ip_tunnel_need_metadata);
 
 void ip_tunnel_unneed_metadata(void)
 {
-	static_key_slow_dec(&ip_tunnel_metadata_cnt);
+	static_branch_dec(&ip_tunnel_metadata_cnt);
 }
 EXPORT_SYMBOL_GPL(ip_tunnel_unneed_metadata);