[SRU][F:linux-bluefield][PATCH 20/32] bonding: Add helper function to get the xmit slave based on hash

[Daniel Jurgens]

From: Maor Gottlieb <maorg at mellanox.com>

BugLink: https://bugs.launchpad.net/bugs/1926994

Both xor and 802.3ad modes use bond_xmit_hash to get the xmit slave.
Export the logic to helper function so it could be used in the
following patches by the .ndo to get the xmit slave.

Signed-off-by: Maor Gottlieb <maorg at mellanox.com>
Reviewed-by: Jiri Pirko <jiri at mellanox.com>
Reviewed-by: Jay Vosburgh <jay.vosburgh at canonical.com>
Acked-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Saeed Mahameed <saeedm at mellanox.com>
(backported from commit c071d91d2a89b0dac1354673810b36453aed62c4)
Signed-off-by: Daniel Jurgens <danielj at nvidia.com>

Conflicts:
	drivers/net/bonding/bond_main.c
---
 drivers/net/bonding/bond_main.c | 26 ++++++++++++++++++++------
 1 file changed, 20 insertions(+), 6 deletions(-)

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 09bae5b..a0f2697 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -4247,6 +4247,23 @@ int bond_update_slave_arr(struct bonding *bond, struct slave *skipslave)
 	return ret;
 }
 
+static struct slave *bond_xmit_3ad_xor_slave_get(struct bonding *bond,
+						 struct sk_buff *skb,
+						 struct bond_up_slave *slaves)
+{
+	struct slave *slave;
+	unsigned int count;
+	u32 hash;
+
+	hash = bond_xmit_hash(bond, skb);
+	count = slaves ? READ_ONCE(slaves->count) : 0;
+	if (unlikely(!count))
+		return NULL;
+
+	slave = slaves->arr[hash % count];
+	return slave;
+}
+
 /* Use this Xmit function for 3AD as well as XOR modes. The current
  * usable slave array is formed in the control path. The xmit function
  * just calculates hash and sends the packet out.
@@ -4255,16 +4272,13 @@ static netdev_tx_t bond_3ad_xor_xmit(struct sk_buff *skb,
 				     struct net_device *dev)
 {
 	struct bonding *bond = netdev_priv(dev);
-	struct slave *slave;
 	struct bond_up_slave *slaves;
-	unsigned int count;
+	struct slave *slave;
 
 	slaves = rcu_dereference(bond->usable_slaves);
-	count = slaves ? READ_ONCE(slaves->count) : 0;
-	if (likely(count)) {
-		slave = slaves->arr[bond_xmit_hash(bond, skb) % count];
+	slave = bond_xmit_3ad_xor_slave_get(bond, skb, slaves);
+	if (likely(slave))
 		return bond_dev_queue_xmit(bond, skb, slave->dev);
-	}
 	return bond_tx_drop(dev, skb);
 }
 
-- 
1.8.3.1