Re: [PATCH net-next-2.6 1/2] net: Get rid of rtnl_link_stats64 / net_device_stats union

[David Miller <davem@davemloft.net>]

From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Fri, 09 Jul 2010 23:08:54 +0200

> Le vendredi 09 juillet 2010 à 20:11 +0100, Ben Hutchings a écrit :
>> 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>

Applied.