summary refs log tree commit diff
path: root/net/batman-adv
diff options
context:
space:
mode:
authorSven Eckelmann <sven@narfation.org>2017-01-28 10:12:39 +0100
committerSimon Wunderlich <sw@simonwunderlich.de>2017-01-28 10:40:35 +0100
commit7c946062b3ae2b7f002383e5e402113e98ad3c77 (patch)
tree03db0aab75359f626c79d66553331a3aee6d3823 /net/batman-adv
parentc33705188c493b7de3b8dc2956d67de91b444727 (diff)
downloadlinux-7c946062b3ae2b7f002383e5e402113e98ad3c77.tar.gz
batman-adv: Fix double call of dev_queue_xmit
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.davem@davemloft.net

Fixes: c33705188c49 ("batman-adv: Treat NET_XMIT_CN as transmit successfully")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Diffstat (limited to 'net/batman-adv')
-rw-r--r--net/batman-adv/send.c4
1 files changed, 3 insertions, 1 deletions
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;