net: export netdev_stats_to_stats64

Some drivers use internal netdev stats member to store part of their
stats, yet advertize ndo_get_stats64() to implement some 64bit fields.

Allow them to use netdev_stats_to_stats64() helper to make the copy of
netdev stats before they compute their 64bit counters.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/netdevice.h

@@ -2557,6 +2557,8 @@ extern void		dev_load(struct net *net, const char *name);
 extern void		dev_mcast_init(void);
 extern struct rtnl_link_stats64 *dev_get_stats(struct net_device *dev,
 					       struct rtnl_link_stats64 *storage);
+extern void netdev_stats_to_stats64(struct rtnl_link_stats64 *stats64,
+				    const struct net_device_stats *netdev_stats);
 
 extern int		netdev_max_backlog;
 extern int		netdev_tstamp_prequeue;

net/core/dev.c

@@ -5834,12 +5834,12 @@ void netdev_run_todo(void)
 /* Convert net_device_stats to rtnl_link_stats64.  They have the same
  * fields in the same order, with only the type differing.
  */
-static void netdev_stats_to_stats64(struct rtnl_link_stats64 *stats64,
-				    const struct net_device_stats *netdev_stats)
+void netdev_stats_to_stats64(struct rtnl_link_stats64 *stats64,
+			     const struct net_device_stats *netdev_stats)
 {
 #if BITS_PER_LONG == 64
-        BUILD_BUG_ON(sizeof(*stats64) != sizeof(*netdev_stats));
-        memcpy(stats64, netdev_stats, sizeof(*stats64));
+	BUILD_BUG_ON(sizeof(*stats64) != sizeof(*netdev_stats));
+	memcpy(stats64, netdev_stats, sizeof(*stats64));
 #else
 	size_t i, n = sizeof(*stats64) / sizeof(u64);
 	const unsigned long *src = (const unsigned long *)netdev_stats;
@@ -5851,6 +5851,7 @@ static void netdev_stats_to_stats64(struct rtnl_link_stats64 *stats64,
 		dst[i] = src[i];
 #endif
 }
+EXPORT_SYMBOL(netdev_stats_to_stats64);
 
 /**
  *	dev_get_stats	- get network device statistics