netdev - [PATCH net-next V3 2/8] net/bonding: Take IP hash logic into a helper

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Date:   Sun, 17 Jan 2021 16:59:43 +0200
From:   Tariq Toukan <tariqt@...dia.com>
To:     "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>
Cc:     Boris Pismenny <borisp@...dia.com>, netdev@...r.kernel.org,
        Tariq Toukan <ttoukan.linux@...il.com>,
        Moshe Shemesh <moshe@...dia.com>,
        Jay Vosburgh <j.vosburgh@...il.com>,
        Veaceslav Falico <vfalico@...il.com>,
        Andy Gospodarek <andy@...yhouse.net>,
        John Fastabend <john.fastabend@...il.com>,
        Daniel Borkmann <daniel@...earbox.net>,
        Jarod Wilson <jarod@...hat.com>,
        Ivan Vecera <ivecera@...hat.com>,
        Tariq Toukan <tariqt@...dia.com>
Subject: [PATCH net-next V3 2/8] 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@...dia.com>
Reviewed-by: Boris Pismenny <borisp@...dia.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 ad5192ee1845..759ad22b7279 100644
--- 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 ----------------------------*/
-- 
2.21.0