net: Get rid of rtnl_link_stats64 / net_device_stats union

In commit be1f3c2c027cc5ad735df6a45a542ed1db7ec48b "net: Enable 64-bit
net device statistics on 32-bit architectures" I redefined struct
net_device_stats so that it could be used in a union with struct
rtnl_link_stats64, avoiding the need for explicit copying or
conversion between the two.  However, this is unsafe because there is
no locking required and no lock consistently held around calls to
dev_get_stats() and use of the statistics structure it returns.

In commit 28172739f0a276eb8d6ca917b3974c2edb036da3 "net: fix 64 bit
counters on 32 bit arches" Eric Dumazet dealt with that problem by
requiring callers of dev_get_stats() to provide storage for the
result.  This means that the net_device::stats64 field and the padding
in struct net_device_stats are now redundant, so remove them.

Update the comment on net_device_ops::ndo_get_stats64 to reflect its
new usage.

Change dev_txq_stats_fold() to use struct rtnl_link_stats64, since
that is what all its callers are really using and it is no longer
going to be compatible with struct net_device_stats.

Eric Dumazet suggested the separate function for the structure
conversion.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 1 deletions

diff --git a/net/8021q/vlan_dev.c b/net/8021q/vlan_dev.c
index a1b8171cfa7b..7cb285f96b99 100644
--- a/net/8021q/vlan_dev.c
+++ b/net/8021q/vlan_dev.c
@@ -805,7 +805,7 @@ static u32 vlan_ethtool_get_flags(struct net_device *dev)
 
 static struct rtnl_link_stats64 *vlan_dev_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
 {
-        dev_txq_stats_fold(dev, (struct net_device_stats *)stats);
+        dev_txq_stats_fold(dev, stats);
 
         if (vlan_dev_info(dev)->vlan_rx_stats) {
                 struct vlan_rx_stats *p, accum = {0};