Re: [PATCHv3 2/2] sfc: Implement 64-bit net device statistics on all architectures

[Eric Dumazet <eric.dumazet@gmail.com>]

Le lundi 05 juillet 2010 à 20:16 +0200, Eric Dumazet a écrit :
> Le mardi 08 juin 2010 à 18:21 +0100, Ben Hutchings a écrit :
> > Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
> > ---
> > This is unchanged from v1.
> > 
> > Ben.
> > 
> >  drivers/net/sfc/efx.c |    6 +++---
> >  1 files changed, 3 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/net/sfc/efx.c b/drivers/net/sfc/efx.c
> > index 26b0cc2..8ad476a 100644
> > --- a/drivers/net/sfc/efx.c
> > +++ b/drivers/net/sfc/efx.c
> > @@ -1492,11 +1492,11 @@ static int efx_net_stop(struct net_device *net_dev)
> >  }
> >  
> >  /* Context: process, dev_base_lock or RTNL held, non-blocking. */
> > -static struct net_device_stats *efx_net_stats(struct net_device *net_dev)
> > +static struct rtnl_link_stats64 *efx_net_stats(struct net_device *net_dev)
> >  {
> >  	struct efx_nic *efx = netdev_priv(net_dev);
> >  	struct efx_mac_stats *mac_stats = &efx->mac_stats;
> > -	struct net_device_stats *stats = &net_dev->stats;
> > +	struct rtnl_link_stats64 *stats = &net_dev->stats64;
> >  
> >  	spin_lock_bh(&efx->stats_lock);
> >  	efx->type->update_stats(efx);
> > @@ -1630,7 +1630,7 @@ static void efx_set_multicast_list(struct net_device *net_dev)
> >  static const struct net_device_ops efx_netdev_ops = {
> >  	.ndo_open		= efx_net_open,
> >  	.ndo_stop		= efx_net_stop,
> > -	.ndo_get_stats		= efx_net_stats,
> > +	.ndo_get_stats64	= efx_net_stats,
> >  	.ndo_tx_timeout		= efx_watchdog,
> >  	.ndo_start_xmit		= efx_hard_start_xmit,
> >  	.ndo_validate_addr	= eth_validate_addr,
> > -- 
> > 1.6.2.5
> > 
> 
> Ben, David
> 
> I believe following patch is needed after our recent commits.
> Not sure a seqlock is really needed, maybe a spinlock would be enough.
> 

One other way would be to add a rtnl_link_stats64 param to
ndo_get_stats64() method, and ask drivers to copy their stats in this
zone, instead of returning &dev->stats64 or something...

And also change dev_get_stats() with this new parameter.

Each caller would use a private copy, with no risk of concurrent
updates.