netdev - [PATCH net-next v3 3/5] bonding: simplify broadcast

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Date:	Thu,  1 Aug 2013 16:54:49 +0200
From:	Nikolay Aleksandrov <nikolay@...hat.com>
To:	netdev@...r.kernel.org
Cc:	davem@...emloft.net, andy@...yhouse.net, fubar@...ibm.com
Subject: [PATCH net-next v3 3/5] bonding: simplify broadcast_xmit function

From: Nikolay Aleksandrov <razor@...ckWall.org>

We don't need to start from the curr_active_slave as the frame will be
sent to all eligible slaves anyway, so we remove the unnecessary local
variables, checks and comments, and make it use the standard list API.
This has the nice side-effect that later when it's converted to RCU
a race condition will be avoided which could lead to double packet tx.

Signed-off-by: Nikolay Aleksandrov <nikolay@...hat.com>
---
v2,v3: no changes

 drivers/net/bonding/bond_main.c | 52 +++++++++++++----------------------------
 1 file changed, 16 insertions(+), 36 deletions(-)

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 9bdc701..5f9d2fa 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -3910,52 +3910,32 @@ static int bond_xmit_xor(struct sk_buff *skb, struct net_device *bond_dev)
 	return NETDEV_TX_OK;
 }
 
-/*
- * in broadcast mode, we send everything to all usable interfaces.
- */
+/* in broadcast mode, we send everything to all usable interfaces. */
 static int bond_xmit_broadcast(struct sk_buff *skb, struct net_device *bond_dev)
 {
 	struct bonding *bond = netdev_priv(bond_dev);
-	struct slave *slave, *start_at;
-	struct net_device *tx_dev = NULL;
-	int i;
-	int res = 1;
-
-	start_at = bond->curr_active_slave;
-	if (!start_at)
-		goto out;
+	struct slave *slave = NULL;
 
-	bond_for_each_slave_from(bond, slave, i, start_at) {
-		if (IS_UP(slave->dev) &&
-		    (slave->link == BOND_LINK_UP) &&
-		    bond_is_active_slave(slave)) {
-			if (tx_dev) {
-				struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
-				if (!skb2) {
-					pr_err("%s: Error: bond_xmit_broadcast(): skb_clone() failed\n",
-					       bond_dev->name);
-					continue;
-				}
+	bond_for_each_slave(bond, slave) {
+		if (bond_is_last_slave(bond, slave))
+			break;
+		if (IS_UP(slave->dev) && slave->link == BOND_LINK_UP) {
+			struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
 
-				res = bond_dev_queue_xmit(bond, skb2, tx_dev);
-				if (res) {
-					kfree_skb(skb2);
-					continue;
-				}
+			if (!skb2) {
+				pr_err("%s: Error: bond_xmit_broadcast(): skb_clone() failed\n",
+				       bond_dev->name);
+				continue;
 			}
-			tx_dev = slave->dev;
+			/* bond_dev_queue_xmit always returns 0 */
+			bond_dev_queue_xmit(bond, skb2, slave->dev);
 		}
 	}
-
-	if (tx_dev)
-		res = bond_dev_queue_xmit(bond, skb, tx_dev);
-
-out:
-	if (res)
-		/* no suitable interface, frame not sent */
+	if (slave && IS_UP(slave->dev) && slave->link == BOND_LINK_UP)
+		bond_dev_queue_xmit(bond, skb, slave->dev);
+	else
 		kfree_skb(skb);
 
-	/* frame sent to all suitable interfaces */
 	return NETDEV_TX_OK;
 }
 
-- 
1.8.1.4

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