Re: [PATCH net-next 3/4] net: Call into DSA netdevice_ops wrappers

[Vladimir Oltean <olteanv@gmail.com>]

On Fri, Jul 17, 2020 at 08:05:32PM -0700, Florian Fainelli wrote:
> Make the core net_device code call into our ndo_do_ioctl() and
> ndo_get_phys_port_name() functions via the wrappers defined previously
> 
> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
> ---
>  net/core/dev.c       | 5 +++++
>  net/core/dev_ioctl.c | 5 +++++
>  2 files changed, 10 insertions(+)
> 
> diff --git a/net/core/dev.c b/net/core/dev.c
> index 062a00fdca9b..19f1abc26fcd 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -98,6 +98,7 @@
>  #include <net/busy_poll.h>
>  #include <linux/rtnetlink.h>
>  #include <linux/stat.h>
> +#include <net/dsa.h>
>  #include <net/dst.h>
>  #include <net/dst_metadata.h>
>  #include <net/pkt_sched.h>
> @@ -8602,6 +8603,10 @@ int dev_get_phys_port_name(struct net_device *dev,
>  	const struct net_device_ops *ops = dev->netdev_ops;
>  	int err;
>  
> +	err  = dsa_ndo_get_phys_port_name(dev, name, len);

Stupid question, but why must these be calls to an inline function whose
name is derived through macro concatenation and hardcoded for 2
arguments, then pass through an additional function pointer found in a
DSA-specific lookup table, and why cannot DSA instead simply export
these 2 symbols (with a static inline EOPNOTSUPP fallback), and simply
provide the implementation inside those?

> +	if (err == 0 || err != -EOPNOTSUPP)
> +		return err;
> +
>  	if (ops->ndo_get_phys_port_name) {
>  		err = ops->ndo_get_phys_port_name(dev, name, len);
>  		if (err != -EOPNOTSUPP)
> diff --git a/net/core/dev_ioctl.c b/net/core/dev_ioctl.c
> index a213c703c90a..b2cf9b7bb7b8 100644
> --- a/net/core/dev_ioctl.c
> +++ b/net/core/dev_ioctl.c
> @@ -5,6 +5,7 @@
>  #include <linux/rtnetlink.h>
>  #include <linux/net_tstamp.h>
>  #include <linux/wireless.h>
> +#include <net/dsa.h>
>  #include <net/wext.h>
>  
>  /*
> @@ -231,6 +232,10 @@ static int dev_do_ioctl(struct net_device *dev,
>  	const struct net_device_ops *ops = dev->netdev_ops;
>  	int err = -EOPNOTSUPP;
>  
> +	err = dsa_ndo_do_ioctl(dev, ifr, cmd);
> +	if (err == 0 || err != -EOPNOTSUPP)
> +		return err;
> +
>  	if (ops->ndo_do_ioctl) {
>  		if (netif_device_present(dev))
>  			err = ops->ndo_do_ioctl(dev, ifr, cmd);
> -- 
> 2.25.1
> 

Thanks,
-Vladimir