[PATCH RFC net-next 4/6] net/bonding: Take IP hash logic into a helper

[Tariq Toukan <tariqt@nvidia.com>]

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>
---
 drivers/net/bonding/bond_main.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 5fe5232cc3f3..8bc7629a2805 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -3539,6 +3539,16 @@ 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
@@ -3569,12 +3579,8 @@ 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 ----------------------------*/
-- 
2.21.0