Re: [RFC PATCH net-next v3 15/21] ethtool: provide link settings and link modes in GET_SETTINGS request
From: Michal Kubecek
Date: Thu Feb 21 2019 - 05:14:29 EST
On Wed, Feb 20, 2019 at 07:14:50PM -0800, Florian Fainelli wrote:
> On 2/18/2019 10:22 AM, Michal Kubecek wrote:
> > +#define ETH_SETTINGS_IM_LINKINFO 0x01
> > +#define ETH_SETTINGS_IM_LINKMODES 0x02
> > +
> > +#define ETH_SETTINGS_IM_ALL 0x03
>
> You could define ETH_SETTINGS_IM_ALL as:
>
> #define ETH_SETTING_IM_ALL \
> (ETH_SETTINGS_IM_LINKINFO |
> ETH_SETTINGS_IM_LINMODES)
>
> that would scale better IMHO, especially given that you have to keep
> bumping that mask with new bits in subsequent patches.
I'm considering going even further and using something similar to what
is used for NETIF_F_* constants so that the *_ALL value would be
calculated automatically. But I'm not sure if it's not too fancy for
a uapi header file.
> > + if (tb[ETHA_SETTINGS_INFOMASK])
> > + req_info->req_mask = nla_get_u32(tb[ETHA_SETTINGS_INFOMASK]);
> > + if (tb[ETHA_SETTINGS_COMPACT])
> > + req_info->compact = true;
> > + if (req_info->req_mask == 0)
> > + req_info->req_mask = ETH_SETTINGS_IM_ALL;
>
> What if userland is newer than the kernel and specifies a req_mask with
> bits set that you don't support? Should not you always do an &
> ETH_SETTINGS_IM_ALL here?
In that case only known bits would be handled and the check at the end
of prepare_info() would add a warning to extack that part of the
information couldn't be provided (same as if some of the recognized
parts didn't have necessary ethtool_ops handlers or if they failed).
Michal