From: Sven Eckelmann <s...@narfation.org>
The net_xmit_eval has side effects because it is not making sure that e
isn't evaluated twice.
#define net_xmit_eval(e) ((e) == NET_XMIT_CN ? 0 : (e))
The code requested by David Miller [1]
return net_xmit_eval(dev_queue_xmit(skb));
will get transformed into
return ((dev_queue_xmit(skb)) == NET_XMIT_CN ? 0 : (dev_queue_xmit(skb)))
dev_queue_xmit will therefore be tried again (with an already consumed skb)
whenever the return code is not NET_XMIT_CN.
[1]
https://lkml.kernel.org/r/20170125.225624.965229145391320056.da...@davemloft.net
Fixes: c33705188c49 ("batman-adv: Treat NET_XMIT_CN as transmit successfully")
Signed-off-by: Sven Eckelmann <s...@narfation.org>
Signed-off-by: Simon Wunderlich <s...@simonwunderlich.de>
---
net/batman-adv/send.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/net/batman-adv/send.c b/net/batman-adv/send.c
index d9b2889064a6..1489ec27daff 100644
--- a/net/batman-adv/send.c
+++ b/net/batman-adv/send.c
@@ -77,6 +77,7 @@ int batadv_send_skb_packet(struct sk_buff *skb,
{
struct batadv_priv *bat_priv;
struct ethhdr *ethhdr;
+ int ret;
bat_priv = netdev_priv(hard_iface->soft_iface);
@@ -115,7 +116,8 @@ int batadv_send_skb_packet(struct sk_buff *skb,
* congestion and traffic shaping, it drops and returns NET_XMIT_DROP
* (which is > 0). This will not be treated as an error.
*/
- return net_xmit_eval(dev_queue_xmit(skb));
+ ret = dev_queue_xmit(skb);
+ return net_xmit_eval(ret);
send_skb_err:
kfree_skb(skb);
return NET_XMIT_DROP;
--
2.11.0
