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infiniband: ipoib: Sanitize neighbour handling in ipoib_main.c

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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>
This commit is contained in:
David Miller 2011-12-02 16:52:44 +00:00 committed by David S. Miller
parent 51e059bdd6
commit 17e6abeec4
1 changed files with 12 additions and 12 deletions
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24
drivers/infiniband/ulp/ipoib/ipoib_main.c
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@ -556,15 +556,13 @@ static int path_rec_start(struct net_device *dev,
}
/* 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 @@ err_drop:
}
/* 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 @@ static int ipoib_start_xmit(struct sk_buff *skb, struct net_device *dev)
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 @@ static int ipoib_start_xmit(struct sk_buff *skb, struct net_device *dev)
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;
}