net/bonding: Take IP hash logic into a helper

Hash logic on L3 will be used in a downstream patch for one more use
case.
Take it to a function for a better code reuse.

Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Boris Pismenny <borisp@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index ad5192e..759ad22 100644 (file)
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -3541,6 +3541,16 @@ static bool bond_flow_dissect(struct bonding *bond, struct sk_buff *skb,
        return true;
 }
 
+static u32 bond_ip_hash(u32 hash, struct flow_keys *flow)
+{
+       hash ^= (__force u32)flow_get_u32_dst(flow) ^
+               (__force u32)flow_get_u32_src(flow);
+       hash ^= (hash >> 16);
+       hash ^= (hash >> 8);
+       /* discard lowest hash bit to deal with the common even ports pattern */
+       return hash >> 1;
+}
+
 /**
  * bond_xmit_hash - generate a hash value based on the xmit policy
  * @bond: bonding device
@@ -3571,12 +3581,8 @@ u32 bond_xmit_hash(struct bonding *bond, struct sk_buff *skb)
                else
                        memcpy(&hash, &flow.ports.ports, sizeof(hash));
        }
-       hash ^= (__force u32)flow_get_u32_dst(&flow) ^
-               (__force u32)flow_get_u32_src(&flow);
-       hash ^= (hash >> 16);
-       hash ^= (hash >> 8);
 
-       return hash >> 1;
+       return bond_ip_hash(hash, &flow);
 }
 
 /*-------------------------- Device entry points ----------------------------*/