diff options
| author | Ben Hutchings <bhutchings@solarflare.com> | 2011-09-02 23:23:00 +0100 |
|---|---|---|
| committer | Ben Hutchings <bhutchings@solarflare.com> | 2012-01-27 00:10:45 +0000 |
| commit | 1cb345220f135dcca24f01cc04cbb97a8242d419 (patch) | |
| tree | 059ec907cd50bd10114bd942d0ffbfa7fd080aa2 /drivers/net/ethernet/sfc/efx.c | |
| parent | 788ec41cc843f12e8d0eba5f2b37af18b76654a5 (diff) | |
| download | lwn-1cb345220f135dcca24f01cc04cbb97a8242d419.tar.gz lwn-1cb345220f135dcca24f01cc04cbb97a8242d419.zip | |
sfc: Hold efx_nic::stats_lock while reading efx_nic::mac_stats
efx_nic::stats_lock is used to serialise stats updates, but each
reader was dropping it before it finished reading efx_nic::mac_stats.
If there were concurrent stats reads using procfs, or one using procfs
and one using ethtool, an update could race with a read. On a 32-bit
system, the reader could see word-tearing of 64-bit stats (32 bits of
the old value and 32 bits of the new).
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Diffstat (limited to 'drivers/net/ethernet/sfc/efx.c')
| -rw-r--r-- | drivers/net/ethernet/sfc/efx.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/net/ethernet/sfc/efx.c b/drivers/net/ethernet/sfc/efx.c index eff5d300aa0a..8f4cbb642bf2 100644 --- a/drivers/net/ethernet/sfc/efx.c +++ b/drivers/net/ethernet/sfc/efx.c @@ -1743,8 +1743,8 @@ static struct rtnl_link_stats64 *efx_net_stats(struct net_device *net_dev, struc struct efx_mac_stats *mac_stats = &efx->mac_stats; spin_lock_bh(&efx->stats_lock); + efx->type->update_stats(efx); - spin_unlock_bh(&efx->stats_lock); stats->rx_packets = mac_stats->rx_packets; stats->tx_packets = mac_stats->tx_packets; @@ -1768,6 +1768,8 @@ static struct rtnl_link_stats64 *efx_net_stats(struct net_device *net_dev, struc stats->tx_errors = (stats->tx_window_errors + mac_stats->tx_bad); + spin_unlock_bh(&efx->stats_lock); + return stats; } |