Re: [PATCH net-next] ethtool: ioctl: improve error checking for set_wol

[Justin Chen]

On 6/1/23 9:22 AM, Justin Chen wrote:
> On 6/1/2023 8:55 AM, Simon Horman wrote:
> > + Daniil Tatianin <d-tatianin@xxxxxxxxxxxxxx>, Andrew Lunn 
> > <andrew@xxxxxxx>
> >    as per ./scripts/get_maintainer.pl --git-min-percent 25 
> > net/ethtool/ioctl.c
> >
> > On Wed, May 31, 2023 at 01:53:49PM -0700, Justin Chen wrote:
> > > The netlink version of set_wol checks for not supported wolopts and 
> > > avoids
> > > setting wol when the correct wolopt is already set. If we do the same 
> > > with
> > > the ioctl version then we can remove these checks from the driver layer.
> >
> > Hi Justin,
> >
> > Are you planning follow-up patches for the driver layer?
>
> I was planning to for the Broadcom drivers since those I can test. But I 
> could do it across the board if that is preferred.
>
> > > Signed-off-by: Justin Chen <justin.chen@xxxxxxxxxxxx>
> > > ---
> > >   net/ethtool/ioctl.c | 14 ++++++++++++--
> > >   1 file changed, 12 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
> > > index 6bb778e10461..80f456f83db0 100644
> > > --- a/net/ethtool/ioctl.c
> > > +++ b/net/ethtool/ioctl.c
> > > @@ -1436,15 +1436,25 @@ static int ethtool_get_wol(struct net_device 
> > > *dev, char __user *useraddr)
> > >   static int ethtool_set_wol(struct net_device *dev, char __user 
> > > *useraddr)
> > >   {
> > > -    struct ethtool_wolinfo wol;
> > > +    struct ethtool_wolinfo wol, cur_wol;
> > >       int ret;
> > > -    if (!dev->ethtool_ops->set_wol)
> > > +    if (!dev->ethtool_ops->get_wol || !dev->ethtool_ops->set_wol)
> > >           return -EOPNOTSUPP;
> >
> > Are there cases where (in-tree) drivers provide set_wol byt not get_wol?
> > If so, does this break their set_wol support?
>
> My original thought was to match netlink set wol behavior. So drivers 
> that do that won't work with netlink set_wol right now. I'll skim around 
> to see if any drivers do this. But I would reckon this should be a 
> driver fix.
>
> Thanks,
> Justin

I see a driver at drivers/net/phy/microchip.c. But this is a phy driver 
set_wol hook.

Justin

> > > +    memset(&cur_wol, 0, sizeof(struct ethtool_wolinfo));
> > > +    cur_wol.cmd = ETHTOOL_GWOL;
> > > +    dev->ethtool_ops->get_wol(dev, &cur_wol);
> > > +
> > >       if (copy_from_user(&wol, useraddr, sizeof(wol)))
> > >           return -EFAULT;
> > > +    if (wol.wolopts & ~cur_wol.supported)
> > > +        return -EOPNOTSUPP;
> > > +
> > > +    if (wol.wolopts == cur_wol.wolopts)
> > > +        return 0;
> > > +
> > >       ret = dev->ethtool_ops->set_wol(dev, &wol);
> > >       if (ret)
> > >           return ret;

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