Re: [PATCH net-next v2 06/16] net: bridge: Stop calling switchdev_port_attr_get()

[Ido Schimmel <idosch@mellanox.com>]

On Sun, Feb 10, 2019 at 09:50:55AM -0800, Florian Fainelli wrote:
> Now that all switchdev drivers have been converted to checking the
> bridge port flags during the prepare phase of the
> switchdev_port_attr_set(), we can move straight to trying to set the
> desired flag through SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS.
> 
> Acked-by: Jiri Pirko <jiri@mellanox.com>
> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
> ---
>  net/bridge/br_switchdev.c | 20 +++-----------------
>  1 file changed, 3 insertions(+), 17 deletions(-)
> 
> diff --git a/net/bridge/br_switchdev.c b/net/bridge/br_switchdev.c
> index db9e8ab96d48..939f300522c5 100644
> --- a/net/bridge/br_switchdev.c
> +++ b/net/bridge/br_switchdev.c
> @@ -64,29 +64,15 @@ int br_switchdev_set_port_flag(struct net_bridge_port *p,
>  {
>  	struct switchdev_attr attr = {
>  		.orig_dev = p->dev,
> -		.id = SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS_SUPPORT,
> +		.id = SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS,
> +		.flags = SWITCHDEV_F_DEFER,

How does this work? You defer the operation, so the driver cannot veto
it. This is why we have SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS_SUPPORT
which is not deferred.

> +		.u.brport_flags = flags,
>  	};
>  	int err;
>  
>  	if (mask & ~BR_PORT_FLAGS_HW_OFFLOAD)
>  		return 0;
>  
> -	err = switchdev_port_attr_get(p->dev, &attr);
> -	if (err == -EOPNOTSUPP)
> -		return 0;
> -	if (err)
> -		return err;
> -
> -	/* Check if specific bridge flag attribute offload is supported */
> -	if (!(attr.u.brport_flags_support & mask)) {
> -		br_warn(p->br, "bridge flag offload is not supported %u(%s)\n",
> -			(unsigned int)p->port_no, p->dev->name);
> -		return -EOPNOTSUPP;
> -	}
> -
> -	attr.id = SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS;
> -	attr.flags = SWITCHDEV_F_DEFER;
> -	attr.u.brport_flags = flags;
>  	err = switchdev_port_attr_set(p->dev, &attr);
>  	if (err) {
>  		br_warn(p->br, "error setting offload flag on port %u(%s)\n",
> -- 
> 2.19.1
>