[PATCH net-next v3] ip_tunnel: Add dst_cache support in lwtunnel_state of ip tunnel

[wenxu]

From: wenxu <we...@ucloud.cn>

The lwtunnel_state is not init the dst_cache Which make the
ip_md_tunnel_xmit can't use the dst_cache. It will lookup
route table every packets.

Signed-off-by: wenxu <we...@ucloud.cn>
---
 net/core/lwtunnel.c       |  3 ++-
 net/ipv4/ip_tunnel_core.c | 20 ++++++++++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/net/core/lwtunnel.c b/net/core/lwtunnel.c
index 0b17175..f6301af 100644
--- a/net/core/lwtunnel.c
+++ b/net/core/lwtunnel.c
@@ -123,17 +123,18 @@ int lwtunnel_build_state(u16 encap_type,
        rcu_read_lock();
        ops = rcu_dereference(lwtun_encaps[encap_type]);
        if (likely(ops && ops->build_state && try_module_get(ops->owner))) {
+               rcu_read_unlock();
                found = true;
                ret = ops->build_state(encap, family, cfg, lws, extack);
                if (ret)
                        module_put(ops->owner);
        }
-       rcu_read_unlock();
 
        /* don't rely on -EOPNOTSUPP to detect match as build_state
         * handlers could return it
         */
        if (!found) {
+               rcu_read_unlock();
                NL_SET_ERR_MSG_ATTR(extack, encap,
                                    "LWT encapsulation type not supported");
        }
diff --git a/net/ipv4/ip_tunnel_core.c b/net/ipv4/ip_tunnel_core.c
index 9a0e67b..334e77a 100644
--- a/net/ipv4/ip_tunnel_core.c
+++ b/net/ipv4/ip_tunnel_core.c
@@ -252,6 +252,14 @@ static int ip_tun_build_state(struct nlattr *attr,
 
        tun_info = lwt_tun_info(new_state);
 
+#ifdef CONFIG_DST_CACHE
+       err = dst_cache_init(&tun_info->dst_cache, GFP_KERNEL);
+       if (err) {
+               lwtstate_free(new_state);
+               return err;
+       }
+#endif
+
        if (tb[LWTUNNEL_IP_ID])
                tun_info->key.tun_id = nla_get_be64(tb[LWTUNNEL_IP_ID]);
 
@@ -278,6 +286,15 @@ static int ip_tun_build_state(struct nlattr *attr,
        return 0;
 }
 
+#ifdef CONFIG_DST_CACHE
+static void ip_tun_destroy_state(struct lwtunnel_state *lwtstate)
+{
+       struct ip_tunnel_info *tun_info = lwt_tun_info(lwtstate);
+
+       dst_cache_destroy(&tun_info->dst_cache);
+}
+#endif
+
 static int ip_tun_fill_encap_info(struct sk_buff *skb,
                                  struct lwtunnel_state *lwtstate)
 {
@@ -313,6 +330,9 @@ static int ip_tun_cmp_encap(struct lwtunnel_state *a, 
struct lwtunnel_state *b)
 
 static const struct lwtunnel_encap_ops ip_tun_lwt_ops = {
        .build_state = ip_tun_build_state,
+#ifdef CONFIG_DST_CACHE
+       .destroy_state = ip_tun_destroy_state,
+#endif
        .fill_encap = ip_tun_fill_encap_info,
        .get_encap_size = ip_tun_encap_nlsize,
        .cmp_encap = ip_tun_cmp_encap,
-- 
1.8.3.1