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authorIgor Druzhinin <igor.druzhinin@citrix.com>2019-02-28 14:11:26 +0000
committerDavid S. Miller <davem@davemloft.net>2019-02-28 12:50:37 -0800
commita2288d4e355992d369c50c45d017a85f6061ff71 (patch)
tree29c9e1a705304424084678266ea7fec916fe8c6a
parent99e87f56b48f490fb16b6e0f74691c1e664dea95 (diff)
xen-netback: don't populate the hash cache on XenBus disconnect
Occasionally, during the disconnection procedure on XenBus which includes hash cache deinitialization there might be some packets still in-flight on other processors. Handling of these packets includes hashing and hash cache population that finally results in hash cache data structure corruption. In order to avoid this we prevent hashing of those packets if there are no queues initialized. In that case RCU protection of queues guards the hash cache as well. Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com> Reviewed-by: Paul Durrant <paul.durrant@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/net/xen-netback/hash.c2
-rw-r--r--drivers/net/xen-netback/interface.c7
2 files changed, 9 insertions, 0 deletions
diff --git a/drivers/net/xen-netback/hash.c b/drivers/net/xen-netback/hash.c
index 0ccb021f1e78..10d580c3dea3 100644
--- a/drivers/net/xen-netback/hash.c
+++ b/drivers/net/xen-netback/hash.c
@@ -454,6 +454,8 @@ void xenvif_init_hash(struct xenvif *vif)
if (xenvif_hash_cache_size == 0)
return;
+ BUG_ON(vif->hash.cache.count);
+
spin_lock_init(&vif->hash.cache.lock);
INIT_LIST_HEAD(&vif->hash.cache.list);
}
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index 182d6770f102..6da12518e693 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -153,6 +153,13 @@ static u16 xenvif_select_queue(struct net_device *dev, struct sk_buff *skb,
{
struct xenvif *vif = netdev_priv(dev);
unsigned int size = vif->hash.size;
+ unsigned int num_queues;
+
+ /* If queues are not set up internally - always return 0
+ * as the packet going to be dropped anyway */
+ num_queues = READ_ONCE(vif->num_queues);
+ if (num_queues < 1)
+ return 0;
if (vif->hash.alg == XEN_NETIF_CTRL_HASH_ALGORITHM_NONE)
return fallback(dev, skb, NULL) % dev->real_num_tx_queues;