Re: [PATCH] switchdev: add Kconfig dependencies for bridge

[Simon Horman]

On Mon, Aug 02, 2021 at 08:29:25PM +0200, Arnd Bergmann wrote:
> On Mon, Aug 2, 2021 at 6:23 PM Simon Horman <simon.horman@xxxxxxxxxxxx> wrote:
> > On Mon, Aug 02, 2021 at 04:47:28PM +0200, Arnd Bergmann wrote:
> > > ---
> > > This version seems to pass my randconfig builds for the moment,
> > > but that doesn't mean it's correct either. Please have a closer
> > > look before this gets applied.
> 
> Thank you for taking a look, it seems I have done a particularly bad
> job rebasing
> the patch on top of the previous fix, leaving only the wrong bits ;-)

:)

...

> > > diff --git a/drivers/net/ethernet/netronome/Kconfig b/drivers/net/ethernet/netronome/Kconfig
> > > index b82758d5beed..a298d19e8383 100644
> > > --- a/drivers/net/ethernet/netronome/Kconfig
> > > +++ b/drivers/net/ethernet/netronome/Kconfig
> > > @@ -21,6 +21,7 @@ config NFP
> > >       depends on PCI && PCI_MSI
> > >       depends on VXLAN || VXLAN=n
> > >       depends on TLS && TLS_DEVICE || TLS_DEVICE=n
> > > +     depends on NET_MAY_USE_SWITCHDEV
> > >       select NET_DEVLINK
> > >       select CRC32
> > >       help
> >
> > This seems wrong, the NFP driver doesn't call
> > switchdev_bridge_port_offload()
> 
> Ah right, I actually noticed that earlier and then forgot to remove that hunk.
> 
> Also: is this actually intended or should the driver call
> switchdev_bridge_port_offload() like the other switchdev drivers do?

The NFP driver doesn't implement /use this part of the switchdev API.
It is intentional given the current scope of features implemented.

> > > diff --git a/drivers/net/ethernet/ti/Kconfig b/drivers/net/ethernet/ti/Kconfig
> > > index 07192613256e..a73c6c236b25 100644
> > > --- a/drivers/net/ethernet/ti/Kconfig
> > > +++ b/drivers/net/ethernet/ti/Kconfig
> > > @@ -93,6 +93,7 @@ config TI_CPTS
> > >  config TI_K3_AM65_CPSW_NUSS
> > >       tristate "TI K3 AM654x/J721E CPSW Ethernet driver"
> > >       depends on OF && TI_K3_UDMA_GLUE_LAYER
> > > +     depends on NET_MAY_USE_SWITCHDEV
> > >       select NET_DEVLINK
> > >       select TI_DAVINCI_MDIO
> > >       imply PHY_TI_GMII_SEL
> >
> > I believe this has already been addressed by the following patch in net
> >
> > b0e81817629a ("net: build all switchdev drivers as modules when the bridge is a module")
> 
> I think the fix was wrong here, and that hunk should be reverted.
> The dependency was added to a bool option, where it does not have
> the intended effect.
> 
> I think this is the only remaining thing needed from my patch, so
> the NET_MAY_USE_SWITCHDEV option is not needed either,
> and it could be written as:
> 
> diff --git a/drivers/net/ethernet/ti/Kconfig b/drivers/net/ethernet/ti/Kconfig
> index 07192613256e..e49006a96d49 100644
> --- a/drivers/net/ethernet/ti/Kconfig
> +++ b/drivers/net/ethernet/ti/Kconfig
> @@ -93,6 +93,7 @@ config TI_CPTS
>  config TI_K3_AM65_CPSW_NUSS
>         tristate "TI K3 AM654x/J721E CPSW Ethernet driver"
>         depends on OF && TI_K3_UDMA_GLUE_LAYER
> +       depends on (BRIDGE && NET_SWITCHDEV) || BRIDGE=n || NET_SWITCHDEV=n
>         select NET_DEVLINK
>         select TI_DAVINCI_MDIO
>         imply PHY_TI_GMII_SEL
> @@ -110,7 +111,6 @@ config TI_K3_AM65_CPSW_NUSS
>  config TI_K3_AM65_CPSW_SWITCHDEV
>         bool "TI K3 AM654x/J721E CPSW Switch mode support"
>         depends on TI_K3_AM65_CPSW_NUSS
> -       depends on BRIDGE || BRIDGE=n
>         depends on NET_SWITCHDEV
>         help
>          This enables switchdev support for TI K3 CPSWxG Ethernet
> 
> If this looks correct to you, I can submit it as a standalone patch.

Is there a conflict between your proposed change and the
presence of "depends on NET_SWITCHDEV" ?

BTW, I'm not sure I know how to compile TI_K3_AM65_CPSW_NUSS.
So I'm perhaps not the best arbiter of correctness here.