Re: [PATCH v4 net-next 2/2] net: dsa: qca: ar9331: export stats64

From: Andrew Lunn
Date: Fri Dec 04 2020 - 17:14:03 EST


> > +struct ar9331_sw_stats {
> > + u64 rxbroad;
> > + u64 rxpause;
> > + u64 rxmulti;
> > +};

7> > +struct ar9331_sw_port {
> > + int idx;
> > + struct ar9331_sw_priv *priv;
> > + struct delayed_work mib_read;
> > + struct ar9331_sw_stats stats;


> > +static void ar9331_stats_update(struct ar9331_sw_port *port,
> > + struct rtnl_link_stats64 *stats)
> > +{
> > + struct ar9331_sw_stats *s = &port->stats;
> > +
> > + stats->rx_packets = s->rxbroad + s->rxmulti + s->rx64byte +
> > + s->rx128byte + s->rx256byte + s->rx512byte + s->rx1024byte +
> > + s->rx1518byte + s->rxmaxbyte;
>
> Are all of these port->stats accesses always atomic? I'll need to do
> something similar in my xrs700x driver and want to make sure there
> doesn't need to be a lock between here and where they're updated in
> the delayed work.

Since these are u64, they are not atomic on 32 bit systems.

Take a look at

include/linux/u64_stats_sync.h

Andrewu