Subject: [PATCH net-next 3/7] net/ipv6: Make rt6_multipath_hash similar to fib_multipath_hash

From: David Ahern <[email-masked]>
Date: Wed, 21 Feb 2018 10:49:50 -0800

Make rt6_multipath_hash more of a direct parallel to fib_multipath_hash
and reduce stack and overhead in the process: get_hash_from_flowi6 is
just a wrapper around __get_hash_from_flowi6 with another stack
allocation for flow_keys. Move setting the addresses, protocol and
label into rt6_multipath_hash and allow it to make the call to
flow_hash_from_keys.

Signed-off-by: David Ahern <[email-masked]>
---
 net/ipv6/route.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index ff43add1619d..ab0de69ec67d 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1822,15 +1822,21 @@ static void ip6_multipath_l3_keys(const struct sk_buff *skb,
 u32 rt6_multipath_hash(const struct flowi6 *fl6, const struct sk_buff *skb)
 {
 	struct flow_keys hash_keys;
+	u32 mhash;
 
+	memset(&hash_keys, 0, sizeof(hash_keys));
+	hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
 	if (skb) {
-		memset(&hash_keys, 0, sizeof(hash_keys));
-		hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
 		ip6_multipath_l3_keys(skb, &hash_keys);
-		return flow_hash_from_keys(&hash_keys) >> 1;
+	} else {
+		hash_keys.addrs.v6addrs.src = fl6->saddr;
+		hash_keys.addrs.v6addrs.dst = fl6->daddr;
+		hash_keys.tags.flow_label = (__force u32)fl6->flowlabel;
+		hash_keys.basic.ip_proto = fl6->flowi6_proto;
 	}
+	mhash = flow_hash_from_keys(&hash_keys);
 
-	return get_hash_from_flowi6(fl6) >> 1;
+	return mhash >> 1;
 }
 
 void ip6_route_input(struct sk_buff *skb)
-- 
2.11.0