[PATCH net-next 4/6] net: hip04: Don't free the tx skb when the buffer is not ready for xmit

[Ding Tianhong]

Eric pointed out the problem that the tx skb might already have be freed
by tx completion before enter the xmit queue, so don't notice the tx completion
until the skb is ready to be freed.

Signed-off-by: Ding Tianhong <dingtianhong at huawei.com>
Cc: "David S. Miller" <davem at davemloft.net>
Cc: Eric Dumazet <eric.dumazet at gmail.com>
Cc: Arnd Bergmann <arnd at arndb.de>
Cc: Zhangfei Gao <zhangfei.gao at linaro.org>
Cc: Dan Carpenter <dan.carpenter at oracle.com>
Cc: Joe Perches <joe at perches.com>
---
 drivers/net/ethernet/hisilicon/hip04_eth.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/hisilicon/hip04_eth.c b/drivers/net/ethernet/hisilicon/hip04_eth.c
index 7533858..ff9d19c 100644
--- a/drivers/net/ethernet/hisilicon/hip04_eth.c
+++ b/drivers/net/ethernet/hisilicon/hip04_eth.c
@@ -480,8 +480,6 @@ static int hip04_mac_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 	skb_tx_timestamp(skb);
 
 	hip04_set_xmit_desc(priv, phys);
-	priv->tx_head = TX_NEXT(tx_head);
-	count++;
 	netdev_sent_queue(ndev, skb->len);
 
 	stats->tx_bytes += skb->len;
@@ -489,6 +487,8 @@ static int hip04_mac_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 
 	/* Ensure tx_head update visible to tx reclaim */
 	smp_wmb();
+	count++;
+	priv->tx_head = TX_NEXT(tx_head);
 
 	/* queue is getting full, better start cleaning up now */
 	if (count >= priv->tx_coalesce_frames) {
-- 
1.8.0