Re: [PATCH 2/7] bridge: Keep track of ports capable of flooding.

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Feb 26, 2014 at 10:18:20AM -0500, Vlad Yasevich wrote:
> Keep track of bridge ports that have unicast flooding turned on.
> This will later be used by the algorithm to automatically manage
> address programming and promisc mode.
> 
> Signed-off-by: Vlad Yasevich <vyasevic@redhat.com>
> ---
>  net/bridge/br_if.c       | 60 ++++++++++++++++++++++++++++++++++++++++++++++--
>  net/bridge/br_netlink.c  |  3 +++
>  net/bridge/br_private.h  |  4 ++++
>  net/bridge/br_sysfs_if.c |  6 ++++-
>  4 files changed, 70 insertions(+), 3 deletions(-)
> 
> diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
> index 54d207d..f072b34 100644
> --- a/net/bridge/br_if.c
> +++ b/net/bridge/br_if.c
> @@ -27,6 +27,9 @@
>  
>  #include "br_private.h"
>  
> +static void br_add_flood_port(struct net_bridge_port *p, struct net_bridge *br);
> +static void br_del_flood_port(struct net_bridge_port *p, struct net_bridge *br);
> +

same nitpick about forward declarations of static
functions.
maybe they are ok for bridge, but that's my $.02


>  /*
>   * Determine initial path cost based on speed.
>   * using recommendations from 802.1d standard
> @@ -141,11 +144,14 @@ static void del_nbp(struct net_bridge_port *p)
>  
>  	br_ifinfo_notify(RTM_DELLINK, p);
>  
> +	list_del_rcu(&p->list);
> +
> +	if (p->flags & BR_FLOOD)
> +		br_del_flood_port(p, br);
> +
>  	nbp_vlan_flush(p);
>  	br_fdb_delete_by_port(br, p, 1);
>  
> -	list_del_rcu(&p->list);
> -
>  	dev->priv_flags &= ~IFF_BRIDGE_PORT;
>  
>  	netdev_rx_handler_unregister(dev);

ok so it doesn't matter in which order we do
list_del_rcu and nbp_vlan_flush then?

> @@ -383,6 +389,9 @@ int br_add_if(struct net_bridge *br, struct net_device *dev)
>  	dev_disable_lro(dev);
>  
>  	list_add_rcu(&p->list, &br->port_list);
> +
> +	if (p->flags & BR_FLOOD)
> +		br_add_flood_port(p, br);
>  
>  	netdev_update_features(br->dev);
>  
> @@ -455,3 +464,50 @@ int br_del_if(struct net_bridge *br, struct net_device *dev)
>  
>  	return 0;
>  }
> +
> +static void br_add_flood_port(struct net_bridge_port *p, struct net_bridge *br)
> +{
> +	/* Increment the number of  flooding ports, and if we
> +	 * only have 1 flooding port cache if for future use.
> +	 */
> +	br->n_flood_ports++;
> +	if (br->n_flood_ports == 1)
> +		br->c_flood_port = p;
> +}
> +
> +static void br_del_flood_port(struct net_bridge_port *p, struct net_bridge *br)
> +{
> +	struct net_bridge_port *port;
> +
> +	/* Decrement the  number of flood port.
> +	 * If we are deleting the current flood port, clear
> +	 * the cached port.  If we are down to 1 flood port,
> +	 * set it if it is not set.
> +	 */
> +	br->n_flood_ports--;
> +	if (p == br->c_flood_port)
> +		br->c_flood_port = NULL;
> +
> +	if (br->n_flood_ports == 1) {
> +		list_for_each_entry(port, &p->br->port_list, list) {
> +			if (port->flags & BR_FLOOD) {
> +				br->c_flood_port = port;
> +				break;
> +			}
> +		}
> +	}
> +}
> +
> +void br_port_flags_change(struct net_bridge_port *p, unsigned long mask)
> +{
> +	struct net_bridge *br = p->br;
> +
> +	/* We are only interested FLOOD flag */
> +	if (!(mask & BR_FLOOD))
> +		return;
> +
> +	if (p->flags & BR_FLOOD)
> +		br_add_flood_port(p, br);
> +	else
> +		br_del_flood_port(p, br);
> +}
> diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
> index e74b6d53..01382b9 100644
> --- a/net/bridge/br_netlink.c
> +++ b/net/bridge/br_netlink.c
> @@ -328,6 +328,7 @@ static void br_set_port_flag(struct net_bridge_port *p, struct nlattr *tb[],
>  static int br_setport(struct net_bridge_port *p, struct nlattr *tb[])
>  {
>  	int err;
> +	unsigned long old_flags = p->flags;
>  
>  	br_set_port_flag(p, tb, IFLA_BRPORT_MODE, BR_HAIRPIN_MODE);
>  	br_set_port_flag(p, tb, IFLA_BRPORT_GUARD, BR_BPDU_GUARD);
> @@ -353,6 +354,8 @@ static int br_setport(struct net_bridge_port *p, struct nlattr *tb[])
>  		if (err)
>  			return err;
>  	}
> +
> +	br_port_flags_change(p, old_flags ^ p->flags);
>  	return 0;
>  }
>  
> diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
> index 3ba11bc..26a3987 100644
> --- a/net/bridge/br_private.h
> +++ b/net/bridge/br_private.h
> @@ -290,6 +290,8 @@ struct net_bridge
>  	struct timer_list		topology_change_timer;
>  	struct timer_list		gc_timer;
>  	struct kobject			*ifobj;
> +	struct net_bridge_port		*c_flood_port;
> +	u32				n_flood_ports;

any hints on locking for these fields?
are these all under rtnl?

>  #ifdef CONFIG_BRIDGE_VLAN_FILTERING
>  	u8				vlan_enabled;
>  	struct net_port_vlans __rcu	*vlan_info;
> @@ -415,6 +417,8 @@ int br_del_if(struct net_bridge *br, struct net_device *dev);
>  int br_min_mtu(const struct net_bridge *br);
>  netdev_features_t br_features_recompute(struct net_bridge *br,
>  					netdev_features_t features);
> +void br_port_flags_change(struct net_bridge_port *port,
> +			  unsigned long mask);
>  
>  /* br_input.c */
>  int br_handle_frame_finish(struct sk_buff *skb);
> diff --git a/net/bridge/br_sysfs_if.c b/net/bridge/br_sysfs_if.c
> index 7f66aa4..9ff6691 100644
> --- a/net/bridge/br_sysfs_if.c
> +++ b/net/bridge/br_sysfs_if.c
> @@ -51,7 +51,10 @@ static BRPORT_ATTR(_name, S_IRUGO | S_IWUSR,			\
>  static int store_flag(struct net_bridge_port *p, unsigned long v,
>  		     unsigned long mask)
>  {
> -	unsigned long flags = p->flags;
> +	unsigned long flags;
> +	unsigned long old_flags;
> +
> +	old_flags = flags = p->flags;
>  
>  	if (v)
>  		flags |= mask;
> @@ -60,6 +63,7 @@ static int store_flag(struct net_bridge_port *p, unsigned long v,
>  
>  	if (flags != p->flags) {
>  		p->flags = flags;
> +		br_port_flags_change(p, old_flags ^ flags);
>  		br_ifinfo_notify(RTM_NEWLINK, p);
>  	}
>  	return 0;
> -- 
> 1.8.5.3