On 22/05/2020 00:10, Vladimir Oltean wrote:
> From: Vladimir Oltean <vladimir.olt...@nxp.com>
>
> In cases where the bridge is offloaded by a switchdev, there are
> situations where we can optimize RX filtering towards the host. To be
> precise, the host only needs to do termination, which it can do by
> responding at the MAC addresses of the slave ports and of the bridge
> interface itself. But most notably, it doesn't need to do forwarding,
> so there is no need to see packets with unknown destination address.
>
> But there are, however, cases when a switchdev does need to flood to the
> CPU. Such an example is when the switchdev is bridged with a foreign
> interface, and since there is no offloaded datapath, packets need to
> pass through the CPU. Currently this is the only identified case, but it
> can be extended at any time.
>
> So far, switchdev implementers made driver-level assumptions, such as:
> this chip is never integrated in SoCs where it can be bridged with a
> foreign interface, so I'll just disable host flooding and save some CPU
> cycles. Or: I can never know what else can be bridged with this
> switchdev port, so I must leave host flooding enabled in any case.
>
> Let the bridge drive the host flooding decision, and pass it to
> switchdev via the same mechanism as the external flooding flags.
>
> Signed-off-by: Vladimir Oltean <vladimir.olt...@nxp.com>
> ---
> include/linux/if_bridge.h | 3 +++
> net/bridge/br_if.c | 40 +++++++++++++++++++++++++++++++++++++++
> net/bridge/br_switchdev.c | 4 +++-
> 3 files changed, 46 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/if_bridge.h b/include/linux/if_bridge.h
> index b3a8d3054af0..6891a432862d 100644
> --- a/include/linux/if_bridge.h
> +++ b/include/linux/if_bridge.h
> @@ -49,6 +49,9 @@ struct br_ip_list {
> #define BR_ISOLATED BIT(16)
> #define BR_MRP_AWARE BIT(17)
> #define BR_MRP_LOST_CONT BIT(18)
> +#define BR_HOST_FLOOD BIT(19)
> +#define BR_HOST_MCAST_FLOOD BIT(20)
> +#define BR_HOST_BCAST_FLOOD BIT(21)
>
> #define BR_DEFAULT_AGEING_TIME (300 * HZ)
>
> diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
> index a0e9a7937412..aae59d1e619b 100644
> --- a/net/bridge/br_if.c
> +++ b/net/bridge/br_if.c
> @@ -166,6 +166,45 @@ void br_manage_promisc(struct net_bridge *br)
> }
> }
>
> +static int br_manage_host_flood(struct net_bridge *br)
> +{
> + const unsigned long mask = BR_HOST_FLOOD | BR_HOST_MCAST_FLOOD |
> + BR_HOST_BCAST_FLOOD;
> + struct net_bridge_port *p, *q;
> +
> + list_for_each_entry(p, &br->port_list, list) {
> + unsigned long flags = p->flags;
> + bool sw_bridging = false;
> + int err;
> +
> + list_for_each_entry(q, &br->port_list, list) {
> + if (p == q)
> + continue;
> +
> + if (!netdev_port_same_parent_id(p->dev, q->dev)) {
> + sw_bridging = true;
> + break;
> + }
> + }
> +
> + if (sw_bridging)
> + flags |= mask;
> + else
> + flags &= ~mask;
> +
> + if (flags == p->flags)
> + continue;
> +
> + err = br_switchdev_set_port_flag(p, flags, mask);
> + if (err)
> + return err;
> +
> + p->flags = flags;
> + }
> +
> + return 0;
> +}
> +
> int nbp_backup_change(struct net_bridge_port *p,
> struct net_device *backup_dev)
> {
> @@ -231,6 +270,7 @@ static void nbp_update_port_count(struct net_bridge *br)
> br->auto_cnt = cnt;
> br_manage_promisc(br);
> }
> + br_manage_host_flood(br);
> }
>
Can we do this only at port add/del ?
Right now it will be invoked also by br_port_flags_change() upon BR_AUTO_MASK
flag change.
> static void nbp_delete_promisc(struct net_bridge_port *p)
> diff --git a/net/bridge/br_switchdev.c b/net/bridge/br_switchdev.c
> index 015209bf44aa..360806ac7463 100644
> --- a/net/bridge/br_switchdev.c
> +++ b/net/bridge/br_switchdev.c
> @@ -56,7 +56,9 @@ bool nbp_switchdev_allowed_egress(const struct
> net_bridge_port *p,
>
> /* Flags that can be offloaded to hardware */
> #define BR_PORT_FLAGS_HW_OFFLOAD (BR_LEARNING | BR_FLOOD | \
> - BR_MCAST_FLOOD | BR_BCAST_FLOOD)
> + BR_MCAST_FLOOD | BR_BCAST_FLOOD | \
> + BR_HOST_FLOOD | BR_HOST_MCAST_FLOOD | \
> + BR_HOST_BCAST_FLOOD)
>
> int br_switchdev_set_port_flag(struct net_bridge_port *p,
> unsigned long flags,
>
