Subject: Re: [patch net-next 07/13] dsa: implement ndo_swdev_get_id

From: Florian Fainelli <[email-masked]>
Date: Wed, 03 Sep 2014 16:20:58 -0700

On 09/03/2014 02:24 AM, Jiri Pirko wrote:
> Signed-off-by: Jiri Pirko <[email-masked]>
> ---
>  include/linux/netdevice.h |  3 ++-
>  include/net/dsa.h         |  1 +
>  net/dsa/Kconfig           |  2 +-
>  net/dsa/dsa.c             |  3 +++
>  net/dsa/slave.c           | 10 ++++++++++
>  5 files changed, 17 insertions(+), 2 deletions(-)
> 
> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> index 6a009d1..7ee070f 100644
> --- a/include/linux/netdevice.h
> +++ b/include/linux/netdevice.h
> @@ -41,7 +41,6 @@
>  
>  #include <linux/ethtool.h>
>  #include <net/net_namespace.h>
> -#include <net/dsa.h>
>  #ifdef CONFIG_DCB
>  #include <net/dcbnl.h>
>  #endif
> @@ -1259,6 +1258,8 @@ enum netdev_priv_flags {
>  #define IFF_LIVE_ADDR_CHANGE		IFF_LIVE_ADDR_CHANGE
>  #define IFF_MACVLAN			IFF_MACVLAN
>  
> +#include <net/dsa.h>
> +
>  /**
>   *	struct net_device - The DEVICE structure.
>   *		Actually, this whole structure is a big mistake.  It mixes I/O
> diff --git a/include/net/dsa.h b/include/net/dsa.h
> index 9771292..d60cd42 100644
> --- a/include/net/dsa.h
> +++ b/include/net/dsa.h
> @@ -140,6 +140,7 @@ struct dsa_switch {
>  	u32			phys_mii_mask;
>  	struct mii_bus		*slave_mii_bus;
>  	struct net_device	*ports[DSA_MAX_PORTS];
> +	struct netdev_phys_item_id psid;
>  };
>  
>  static inline bool dsa_is_cpu_port(struct dsa_switch *ds, int p)
> diff --git a/net/dsa/Kconfig b/net/dsa/Kconfig
> index a585fd6..4e144a2 100644
> --- a/net/dsa/Kconfig
> +++ b/net/dsa/Kconfig
> @@ -1,6 +1,6 @@
>  config HAVE_NET_DSA
>  	def_bool y
> -	depends on NETDEVICES && !S390
> +	depends on NETDEVICES && NET_SWITCHDEV && !S390

It does not look like this is necessary, we are only using definitions
from net/dsa.h and include/linux/netdevice.h, and if it was, a 'select'
would be more appropriate here I think.

TBH, I think we should rather drop this patch for now, I do not see any
benefit in providing a random id over no-id at all.

>  
>  # Drivers must select NET_DSA and the appropriate tagging format
>  
> diff --git a/net/dsa/dsa.c b/net/dsa/dsa.c
> index 61f145c..374912d 100644
> --- a/net/dsa/dsa.c
> +++ b/net/dsa/dsa.c
> @@ -202,6 +202,9 @@ dsa_switch_setup(struct dsa_switch_tree *dst, int index,
>  		ds->ports[i] = slave_dev;
>  	}
>  
> +	ds->psid.id_len = MAX_PHYS_ITEM_ID_LEN;
> +	get_random_bytes(ds->psid.id, ds->psid.id_len);
> +
>  	return ds;
>  
>  out_free:
> diff --git a/net/dsa/slave.c b/net/dsa/slave.c
> index 7333a4a..d79a6c7 100644
> --- a/net/dsa/slave.c
> +++ b/net/dsa/slave.c
> @@ -192,6 +192,15 @@ static netdev_tx_t dsa_slave_notag_xmit(struct sk_buff *skb,
>  	return NETDEV_TX_OK;
>  }
>  
> +static int dsa_slave_swdev_get_id(struct net_device *dev,
> +				  struct netdev_phys_item_id *psid)
> +{
> +	struct dsa_slave_priv *p = netdev_priv(dev);
> +	struct dsa_switch *ds = p->parent;
> +
> +	memcpy(psid, &ds->psid, sizeof(*psid));
> +	return 0;
> +}
>  
>  /* ethtool operations *******************************************************/
>  static int
> @@ -323,6 +332,7 @@ static const struct net_device_ops dsa_slave_netdev_ops = {
>  	.ndo_set_rx_mode	= dsa_slave_set_rx_mode,
>  	.ndo_set_mac_address	= dsa_slave_set_mac_address,
>  	.ndo_do_ioctl		= dsa_slave_ioctl,
> +	.ndo_swdev_get_id	= dsa_slave_swdev_get_id,
>  };
>  
>  static const struct dsa_device_ops notag_netdev_ops = {
>