Subject: [PATCH v3 net-next 04/10] net/ipv6: Make rt6_multipath_hash similar to fib_multipath_hash

From: David Ahern <[email-masked]>
Date: Fri, 2 Mar 2018 08:32:15 -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]>
Reviewed-by: Ido Schimmel <[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 190d9690dfe0..5c89af2c54f4 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1833,15 +1833,21 @@ u32 rt6_multipath_hash(const struct flowi6 *fl6, const struct sk_buff *skb,
 		       struct flow_keys *flkeys)
 {
 	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, flkeys);
-		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