From: Simon Horman <simon.horman@netronome.com>
Date: Mon, 4 Dec 2017 11:31:48 +0100
Subject: flow_dissector: dissect tunnel info outside __skb_flow_dissect()
Patch-mainline: v4.16-rc1
Git-commit: 62b32379fd124fea521484ba7e220d8a449f0b59
References: bsc#1109837

Move dissection of tunnel info to outside of the main flow dissection
function, __skb_flow_dissect(). The sole user of this feature, the flower
classifier, is updated to call tunnel info dissection directly, using
skb_flow_dissect_tunnel_info().

This results in a slightly less complex implementation of
__skb_flow_dissect(), in particular removing logic from that call path
which is not used by the majority of users. The expense of this is borne by
the flower classifier which now has to make an extra call for tunnel info
dissection.

This patch should not result in any behavioural change.

Signed-off-by: Simon Horman <simon.horman@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 include/linux/skbuff.h    |    5 +++++
 net/core/flow_dissector.c |   12 +++++-------
 net/sched/cls_flower.c    |    1 +
 3 files changed, 11 insertions(+), 7 deletions(-)

--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1120,6 +1120,11 @@ static inline bool skb_flow_dissect_flow
 				  data, proto, nhoff, hlen, flags);
 }
 
+void
+skb_flow_dissect_tunnel_info(const struct sk_buff *skb,
+			     struct flow_dissector *flow_dissector,
+			     void *target_container);
+
 static inline __u32 skb_get_hash(struct sk_buff *skb)
 {
 	if (!skb->l4_hash && !skb->sw_hash)
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -132,10 +132,10 @@ skb_flow_dissect_set_enc_addr_type(enum
 	ctrl->addr_type = type;
 }
 
-static void
-__skb_flow_dissect_tunnel_info(const struct sk_buff *skb,
-			       struct flow_dissector *flow_dissector,
-			       void *target_container)
+void
+skb_flow_dissect_tunnel_info(const struct sk_buff *skb,
+			     struct flow_dissector *flow_dissector,
+			     void *target_container)
 {
 	struct ip_tunnel_info *info;
 	struct ip_tunnel_key *key;
@@ -211,6 +211,7 @@ __skb_flow_dissect_tunnel_info(const str
 		tp->dst = key->tp_dst;
 	}
 }
+EXPORT_SYMBOL(skb_flow_dissect_tunnel_info);
 
 static enum flow_dissect_ret
 __skb_flow_dissect_mpls(const struct sk_buff *skb,
@@ -562,9 +563,6 @@ bool __skb_flow_dissect(const struct sk_
 					      FLOW_DISSECTOR_KEY_BASIC,
 					      target_container);
 
-	__skb_flow_dissect_tunnel_info(skb, flow_dissector,
-				       target_container);
-
 	if (dissector_uses_key(flow_dissector,
 			       FLOW_DISSECTOR_KEY_ETH_ADDRS)) {
 		struct ethhdr *eth = eth_hdr(skb);
--- a/net/sched/cls_flower.c
+++ b/net/sched/cls_flower.c
@@ -165,6 +165,7 @@ static int fl_classify(struct sk_buff *s
 	 * so do it rather here.
 	 */
 	skb_key.basic.n_proto = skb->protocol;
+	skb_flow_dissect_tunnel_info(skb, &head->dissector, &skb_key);
 	skb_flow_dissect(skb, &head->dissector, &skb_key, 0);
 
 	fl_set_masked_key(&skb_mkey, &skb_key, &head->mask);