diff options
| author | Eric Dumazet <eric.dumazet@gmail.com> | 2010-07-07 14:58:56 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-07-07 14:58:56 -0700 |
| commit | 28172739f0a276eb8d6ca917b3974c2edb036da3 (patch) | |
| tree | b1dc00cfa20c209992e247c6f73601f609f9ca3b /net/core/dev.c | |
| parent | 217d32dc5f299c483ca0d3c8cc6811c72c0339c4 (diff) | |
net: fix 64 bit counters on 32 bit arches
There is a small possibility that a reader gets incorrect values on 32
bit arches. SNMP applications could catch incorrect counters when a
32bit high part is changed by another stats consumer/provider.
One way to solve this is to add a rtnl_link_stats64 param to all
ndo_get_stats64() methods, and also add such a parameter to
dev_get_stats().
Rule is that we are not allowed to use dev->stats64 as a temporary
storage for 64bit stats, but a caller provided area (usually on stack)
Old drivers (only providing get_stats() method) need no changes.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/dev.c')
| -rw-r--r-- | net/core/dev.c | 25 |
1 files changed, 16 insertions, 9 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index 93b8929fa21..92482d7a87a 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3703,7 +3703,8 @@ void dev_seq_stop(struct seq_file *seq, void *v) static void dev_seq_printf_stats(struct seq_file *seq, struct net_device *dev) { - const struct rtnl_link_stats64 *stats = dev_get_stats(dev); + struct rtnl_link_stats64 temp; + const struct rtnl_link_stats64 *stats = dev_get_stats(dev, &temp); seq_printf(seq, "%6s: %7llu %7llu %4llu %4llu %4llu %5llu %10llu %9llu " "%8llu %7llu %4llu %4llu %4llu %5llu %7llu %10llu\n", @@ -5281,23 +5282,29 @@ EXPORT_SYMBOL(dev_txq_stats_fold); /** * dev_get_stats - get network device statistics * @dev: device to get statistics from + * @storage: place to store stats * * Get network statistics from device. The device driver may provide * its own method by setting dev->netdev_ops->get_stats64 or * dev->netdev_ops->get_stats; otherwise the internal statistics * structure is used. */ -const struct rtnl_link_stats64 *dev_get_stats(struct net_device *dev) +const struct rtnl_link_stats64 *dev_get_stats(struct net_device *dev, + struct rtnl_link_stats64 *storage) { const struct net_device_ops *ops = dev->netdev_ops; - if (ops->ndo_get_stats64) - return ops->ndo_get_stats64(dev); - if (ops->ndo_get_stats) - return (struct rtnl_link_stats64 *)ops->ndo_get_stats(dev); - - dev_txq_stats_fold(dev, &dev->stats); - return &dev->stats64; + if (ops->ndo_get_stats64) { + memset(storage, 0, sizeof(*storage)); + return ops->ndo_get_stats64(dev, storage); + } + if (ops->ndo_get_stats) { + memcpy(storage, ops->ndo_get_stats(dev), sizeof(*storage)); + return storage; + } + memcpy(storage, &dev->stats, sizeof(*storage)); + dev_txq_stats_fold(dev, (struct net_device_stats *)storage); + return storage; } EXPORT_SYMBOL(dev_get_stats); |