[PATCH] netdev: pktgen xmit packet through vlan interface

[Zhouyi Zhou <zhouzhouyi@gmail.com>]

As http://www.spinics.net/lists/netdev/msg165015.html
pktgen generates shared packet through vlan interface will cause
oops because of duplicate entering tc queue.

Try to solve this problem by means of packet clone instead of sharing.

Signed-off-by: Zhouyi Zhou <yizhouzhou@ict.ac.cn>
---
 net/core/pktgen.c |   20 +++++++++++++++++---
 1 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index 0304f98..ced07fc 100644
--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -3297,6 +3297,7 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev)
 	netdev_tx_t (*xmit)(struct sk_buff *, struct net_device *)
 		= odev->netdev_ops->ndo_start_xmit;
 	struct netdev_queue *txq;
+	struct sk_buff *nskb = NULL;
 	u16 queue_map;
 	int ret;
 
@@ -3347,8 +3348,18 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev)
 		pkt_dev->last_ok = 0;
 		goto unlock;
 	}
-	atomic_inc(&(pkt_dev->skb->users));
-	ret = (*xmit)(pkt_dev->skb, odev);
+
+	if (pkt_dev->clone_skb && is_vlan_dev(odev)) {
+		nskb = skb_clone(pkt_dev->skb, GFP_ATOMIC);
+		ret = -ENOMEM;
+		if (nskb)
+			ret = (*xmit)(nskb, odev);
+		else
+			nskb = ERR_PTR(ret);
+	} else {
+		atomic_inc(&(pkt_dev->skb->users));
+		ret = (*xmit)(pkt_dev->skb, odev);
+	}
 
 	switch (ret) {
 	case NETDEV_TX_OK:
@@ -3372,7 +3383,10 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev)
 	case NETDEV_TX_LOCKED:
 	case NETDEV_TX_BUSY:
 		/* Retry it next time */
-		atomic_dec(&(pkt_dev->skb->users));
+		if (nskb && !IS_ERR(nskb))
+			kfree_skb(nskb);
+		else
+			atomic_dec(&(pkt_dev->skb->users));
 		pkt_dev->last_ok = 0;
 	}
 unlock:
-- 
1.7.1