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

From: "Michael S. Tsirkin" <[email-masked]>
Date: Wed, 26 Feb 2014 17:53:59 +0200

On Wed, Feb 26, 2014 at 10:41:57AM -0500, Vlad Yasevich wrote:
> On 02/26/2014 10:41 AM, Michael S. Tsirkin wrote:
> > 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 <[email-masked]>
> >> ---
> >>  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
> > 
> 
> Ok.  Will take a look. Just means that I might need to re-order the
> code which may scatter it a bit through the file.

If you would like to make the diff smaller,
this can be a separate patch.

Same applies to all files ...

> > 
> >>  /*
> >>   * 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?
> 
> Nope.  vlan_flush knows which port its working and doesn't touch
> the port list.
> 
> What does touch the port list if br_fdb_delete_by_port, but that only
> touches it in fdb_delete_local(), and it's ok there since we are trying
> to point an existing fdb out a different port.
> 
> Thanks
> -vlad
> 
> > 
> >> @@ -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