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| author | Paul Durrant <Paul.Durrant@citrix.com> | 2016-10-07 10:32:31 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-10-08 05:52:33 +0200 |
| commit | 912e27e85e070596ed4964ebde29fa9781390f2a (patch) | |
| tree | dba537c23128bb30cba34fb2453edb6752e03102 /drivers | |
| parent | Fixing a bug in team driver due to incorrect 'unsigned int' to 'int' conversion (diff) | |
| download | linux-912e27e85e070596ed4964ebde29fa9781390f2a.tar.xz linux-912e27e85e070596ed4964ebde29fa9781390f2a.zip | |
xen-netback: make sure that hashes are not send to unaware frontends
In the case when a frontend only negotiates a single queue with xen-
netback it is possible for a skbuff with a s/w hash to result in a
hash extra_info segment being sent to the frontend even when no hash
algorithm has been configured. (The ndo_select_queue() entry point makes
sure the hash is not set if no algorithm is configured, but this entry
point is not called when there is only a single queue). This can result
in a frontend that is unable to handle extra_info segments being given
such a segment, causing it to crash.
This patch fixes the problem by clearing the hash in ndo_start_xmit()
instead, which is clearly guaranteed to be called irrespective of the
number of queues.
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/net/xen-netback/interface.c | 20 |
1 files changed, 9 insertions, 11 deletions
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c index 4af532a67d95..74dc2bf71428 100644 --- a/drivers/net/xen-netback/interface.c +++ b/drivers/net/xen-netback/interface.c @@ -149,17 +149,8 @@ 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; - if (vif->hash.alg == XEN_NETIF_CTRL_HASH_ALGORITHM_NONE) { - u16 index = fallback(dev, skb) % dev->real_num_tx_queues; - - /* Make sure there is no hash information in the socket - * buffer otherwise it would be incorrectly forwarded - * to the frontend. - */ - skb_clear_hash(skb); - - return index; - } + if (vif->hash.alg == XEN_NETIF_CTRL_HASH_ALGORITHM_NONE) + return fallback(dev, skb) % dev->real_num_tx_queues; xenvif_set_skb_hash(vif, skb); @@ -208,6 +199,13 @@ static int xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev) cb = XENVIF_RX_CB(skb); cb->expires = jiffies + vif->drain_timeout; + /* If there is no hash algorithm configured then make sure there + * is no hash information in the socket buffer otherwise it + * would be incorrectly forwarded to the frontend. + */ + if (vif->hash.alg == XEN_NETIF_CTRL_HASH_ALGORITHM_NONE) + skb_clear_hash(skb); + xenvif_rx_queue_tail(queue, skb); xenvif_kick_thread(queue); |