Subject: [PATCH v2 net-next 03/10] net/ipv4: Simplify fib_multipath_hash with optional flow keys

From: David Ahern <[email-masked]>
Date: Thu, 1 Mar 2018 19:29:43 -0800

As of commit e37b1e978bec5 ("ipv6: route: dissect flow in input path if
fib rules need it") fib_multipath_hash takes an optional flow keys. If
non-NULL it means the skb has already been dissected. If not set, then
fib_multipath_hash needs to call skb_flow_dissect_flow_keys.

Simplify the logic by setting flkeys to the local stack variable keys.
Simplifies fib_multipath_hash by only have 1 set of instructions
setting hash_keys.

Signed-off-by: David Ahern <[email-masked]>
---
 net/ipv4/route.c | 24 ++++++++++--------------
 1 file changed, 10 insertions(+), 14 deletions(-)

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 78338f89370e..a7940b676f52 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1811,24 +1811,20 @@ int fib_multipath_hash(const struct net *net, const struct fib_info *fi,
 			/* short-circuit if we already have L4 hash present */
 			if (skb->l4_hash)
 				return skb_get_hash_raw(skb) >> 1;
+
 			memset(&hash_keys, 0, sizeof(hash_keys));
 
-			if (flkeys) {
-				hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
-				hash_keys.addrs.v4addrs.src = flkeys->addrs.v4addrs.src;
-				hash_keys.addrs.v4addrs.dst = flkeys->addrs.v4addrs.dst;
-				hash_keys.ports.src = flkeys->ports.src;
-				hash_keys.ports.dst = flkeys->ports.dst;
-				hash_keys.basic.ip_proto = flkeys->basic.ip_proto;
-			} else {
+			if (!flkeys) {
 				skb_flow_dissect_flow_keys(skb, &keys, flag);
-				hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
-				hash_keys.addrs.v4addrs.src = keys.addrs.v4addrs.src;
-				hash_keys.addrs.v4addrs.dst = keys.addrs.v4addrs.dst;
-				hash_keys.ports.src = keys.ports.src;
-				hash_keys.ports.dst = keys.ports.dst;
-				hash_keys.basic.ip_proto = keys.basic.ip_proto;
+				flkeys = &keys;
 			}
+
+			hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
+			hash_keys.addrs.v4addrs.src = flkeys->addrs.v4addrs.src;
+			hash_keys.addrs.v4addrs.dst = flkeys->addrs.v4addrs.dst;
+			hash_keys.ports.src = flkeys->ports.src;
+			hash_keys.ports.dst = flkeys->ports.dst;
+			hash_keys.basic.ip_proto = flkeys->basic.ip_proto;
 		} else {
 			memset(&hash_keys, 0, sizeof(hash_keys));
 			hash_keys.control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
-- 
2.11.0