infiniband: ipoib: Sanitize neighbour handling in ipoib_main.c
Reduce the number of dst_get_neighbour_noref() calls within a single
call chain. Primarily by passing the neighbour pointer down to the
helper functions.
Handle dst_get_neighbour_noref() returning NULL in ipoib_start_xmit()
by incrementing the dropped counter and freeing the packet. We don't
want it to fall through into the ARP/RARP/multicast handling, since
that should only happen when skb_dst() is NULL.
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Roland Dreier <roland@purestorage.com>
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_main.c b/drivers/infiniband/ulp/ipoib/ipoib_main.c
index eef6786..3514ca0 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_main.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_main.c
@@ -556,15 +556,13 @@
}
/* called with rcu_read_lock */
-static void neigh_add_path(struct sk_buff *skb, struct net_device *dev)
+static void neigh_add_path(struct sk_buff *skb, struct neighbour *n, struct net_device *dev)
{
struct ipoib_dev_priv *priv = netdev_priv(dev);
struct ipoib_path *path;
struct ipoib_neigh *neigh;
- struct neighbour *n;
unsigned long flags;
- n = dst_get_neighbour_noref(skb_dst(skb));
neigh = ipoib_neigh_alloc(n, skb->dev);
if (!neigh) {
++dev->stats.tx_dropped;
@@ -638,16 +636,13 @@
}
/* called with rcu_read_lock */
-static void ipoib_path_lookup(struct sk_buff *skb, struct net_device *dev)
+static void ipoib_path_lookup(struct sk_buff *skb, struct neighbour *n, struct net_device *dev)
{
struct ipoib_dev_priv *priv = netdev_priv(skb->dev);
- struct dst_entry *dst = skb_dst(skb);
- struct neighbour *n;
/* Look up path record for unicasts */
- n = dst_get_neighbour_noref(dst);
if (n->ha[4] != 0xff) {
- neigh_add_path(skb, dev);
+ neigh_add_path(skb, n, dev);
return;
}
@@ -723,12 +718,17 @@
unsigned long flags;
rcu_read_lock();
- if (likely(skb_dst(skb)))
+ if (likely(skb_dst(skb))) {
n = dst_get_neighbour_noref(skb_dst(skb));
-
+ if (!n) {
+ ++dev->stats.tx_dropped;
+ dev_kfree_skb_any(skb);
+ goto unlock;
+ }
+ }
if (likely(n)) {
if (unlikely(!*to_ipoib_neigh(n))) {
- ipoib_path_lookup(skb, dev);
+ ipoib_path_lookup(skb, n, dev);
goto unlock;
}
@@ -751,7 +751,7 @@
list_del(&neigh->list);
ipoib_neigh_free(dev, neigh);
spin_unlock_irqrestore(&priv->lock, flags);
- ipoib_path_lookup(skb, dev);
+ ipoib_path_lookup(skb, n, dev);
goto unlock;
}