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>
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 8018f6b..17e95e3 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -162,42 +162,32 @@
/*
* Old network device statistics. Fields are native words
* (unsigned long) so they can be read and written atomically.
- * Each field is padded to 64 bits for compatibility with
- * rtnl_link_stats64.
*/
-#if BITS_PER_LONG == 64
-#define NET_DEVICE_STATS_DEFINE(name) unsigned long name
-#elif defined(__LITTLE_ENDIAN)
-#define NET_DEVICE_STATS_DEFINE(name) unsigned long name, pad_ ## name
-#else
-#define NET_DEVICE_STATS_DEFINE(name) unsigned long pad_ ## name, name
-#endif
-
struct net_device_stats {
- NET_DEVICE_STATS_DEFINE(rx_packets);
- NET_DEVICE_STATS_DEFINE(tx_packets);
- NET_DEVICE_STATS_DEFINE(rx_bytes);
- NET_DEVICE_STATS_DEFINE(tx_bytes);
- NET_DEVICE_STATS_DEFINE(rx_errors);
- NET_DEVICE_STATS_DEFINE(tx_errors);
- NET_DEVICE_STATS_DEFINE(rx_dropped);
- NET_DEVICE_STATS_DEFINE(tx_dropped);
- NET_DEVICE_STATS_DEFINE(multicast);
- NET_DEVICE_STATS_DEFINE(collisions);
- NET_DEVICE_STATS_DEFINE(rx_length_errors);
- NET_DEVICE_STATS_DEFINE(rx_over_errors);
- NET_DEVICE_STATS_DEFINE(rx_crc_errors);
- NET_DEVICE_STATS_DEFINE(rx_frame_errors);
- NET_DEVICE_STATS_DEFINE(rx_fifo_errors);
- NET_DEVICE_STATS_DEFINE(rx_missed_errors);
- NET_DEVICE_STATS_DEFINE(tx_aborted_errors);
- NET_DEVICE_STATS_DEFINE(tx_carrier_errors);
- NET_DEVICE_STATS_DEFINE(tx_fifo_errors);
- NET_DEVICE_STATS_DEFINE(tx_heartbeat_errors);
- NET_DEVICE_STATS_DEFINE(tx_window_errors);
- NET_DEVICE_STATS_DEFINE(rx_compressed);
- NET_DEVICE_STATS_DEFINE(tx_compressed);
+ unsigned long rx_packets;
+ unsigned long tx_packets;
+ unsigned long rx_bytes;
+ unsigned long tx_bytes;
+ unsigned long rx_errors;
+ unsigned long tx_errors;
+ unsigned long rx_dropped;
+ unsigned long tx_dropped;
+ unsigned long multicast;
+ unsigned long collisions;
+ unsigned long rx_length_errors;
+ unsigned long rx_over_errors;
+ unsigned long rx_crc_errors;
+ unsigned long rx_frame_errors;
+ unsigned long rx_fifo_errors;
+ unsigned long rx_missed_errors;
+ unsigned long tx_aborted_errors;
+ unsigned long tx_carrier_errors;
+ unsigned long tx_fifo_errors;
+ unsigned long tx_heartbeat_errors;
+ unsigned long tx_window_errors;
+ unsigned long rx_compressed;
+ unsigned long tx_compressed;
};
#endif /* __KERNEL__ */
@@ -666,14 +656,13 @@
* Callback uses when the transmitter has not made any progress
* for dev->watchdog ticks.
*
- * struct rtnl_link_stats64* (*ndo_get_stats64)(struct net_device *dev
+ * struct rtnl_link_stats64* (*ndo_get_stats64)(struct net_device *dev,
* struct rtnl_link_stats64 *storage);
* struct net_device_stats* (*ndo_get_stats)(struct net_device *dev);
* Called when a user wants to get the network device usage
* statistics. Drivers must do one of the following:
- * 1. Define @ndo_get_stats64 to update a rtnl_link_stats64 structure
- * (which should normally be dev->stats64) and return a ponter to
- * it. The structure must not be changed asynchronously.
+ * 1. Define @ndo_get_stats64 to fill in a zero-initialised
+ * rtnl_link_stats64 structure passed by the caller.
* 2. Define @ndo_get_stats to update a net_device_stats structure
* (which should normally be dev->stats) and return a pointer to
* it. The structure may be changed asynchronously only if each
@@ -888,10 +877,7 @@
int ifindex;
int iflink;
- union {
- struct rtnl_link_stats64 stats64;
- struct net_device_stats stats;
- };
+ struct net_device_stats stats;
#ifdef CONFIG_WIRELESS_EXT
/* List of functions to handle Wireless Extensions (instead of ioctl).
@@ -2147,7 +2133,7 @@
extern const struct rtnl_link_stats64 *dev_get_stats(struct net_device *dev,
struct rtnl_link_stats64 *storage);
extern void dev_txq_stats_fold(const struct net_device *dev,
- struct net_device_stats *stats);
+ struct rtnl_link_stats64 *stats);
extern int netdev_max_backlog;
extern int netdev_tstamp_prequeue;
