[PATCH net-next] bridge: del external_learned fdbs from device on flush or ageout

[PATCH net-next] bridge: del external_learned fdbs from device on flush or ageout

[sfeldma]

From: Scott Feldman <sfeldma@gmail.com>

We need to delete from offload the device externally learnded fdbs when any
one of these events happen:

1) Bridge ages out fdb.  (When bridge is doing ageing vs. device doing
ageing.  If device is doing ageing, it would send SWITCHDEV_FDB_DEL
directly).

2) STP state change flushes fdbs on port.

3) User uses sysfs interface to flush fdbs from bridge or bridge port:

	echo 1 >/sys/class/net/BR_DEV/bridge/flush
	echo 1 >/sys/class/net/BR_PORT/brport/flush

4) Offload driver send event SWITCHDEV_FDB_DEL to delete fdb entry.

For rocker, we can now get called to delete fdb entry in wait and nowait
contexts, so set NOWAIT flag when deleting fdb entry.

Signed-off-by: Scott Feldman <sfeldma@gmail.com>
---
 Documentation/networking/switchdev.txt |   11 ++---------
 drivers/net/ethernet/rocker/rocker.c   |    2 +-
 net/bridge/br_fdb.c                    |   17 +++++++++++++++++
 3 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/Documentation/networking/switchdev.txt b/Documentation/networking/switchdev.txt
index 4a94ebc..e460007 100644
--- a/Documentation/networking/switchdev.txt
+++ b/Documentation/networking/switchdev.txt
@@ -251,15 +251,8 @@ out stale FDB entries.  To keep an FDB entry "alive", the driver should refresh
 the FDB entry by calling call_switchdev_notifiers(SWITCHDEV_FDB_ADD, ...).  The
 notification will reset the FDB entry's last-used time to now.  The driver
 should rate limit refresh notifications, for example, no more than once a
-second.  If the FDB entry expires, ndo_fdb_del is called to remove entry from
-the device.  XXX: this last part isn't currently correct: ndo_fdb_del isn't
-called, so the stale entry remains in device...this need to get fixed.
-
-FDB Flush
-^^^^^^^^^
-
-XXX: Unimplemented.  Need to support FDB flush by bridge driver for port and
-remove both static and learned FDB entries.
+second.  If the FDB entry expires, fdb_delete is called to remove entry from
+the device.
 
 STP State Change on Port
 ^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/drivers/net/ethernet/rocker/rocker.c b/drivers/net/ethernet/rocker/rocker.c
index 3aa6caf..22d68c1 100644
--- a/drivers/net/ethernet/rocker/rocker.c
+++ b/drivers/net/ethernet/rocker/rocker.c
@@ -4392,7 +4392,7 @@ static int rocker_port_fdb_del(struct rocker_port *rocker_port,
 			       const struct switchdev_obj_fdb *fdb)
 {
 	__be16 vlan_id = rocker_port_vid_to_vlan(rocker_port, fdb->vid, NULL);
-	int flags = ROCKER_OP_FLAG_REMOVE;
+	int flags = ROCKER_OP_FLAG_NOWAIT | ROCKER_OP_FLAG_REMOVE;
 
 	if (!rocker_port_is_bridged(rocker_port))
 		return -EINVAL;
diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
index 13949a7..be84b7e 100644
--- a/net/bridge/br_fdb.c
+++ b/net/bridge/br_fdb.c
@@ -24,6 +24,7 @@
 #include <linux/atomic.h>
 #include <asm/unaligned.h>
 #include <linux/if_vlan.h>
+#include <net/switchdev.h>
 #include "br_private.h"
 
 static struct kmem_cache *br_fdb_cache __read_mostly;
@@ -130,11 +131,27 @@ static void fdb_del_hw_addr(struct net_bridge *br, const unsigned char *addr)
 	}
 }
 
+static void fdb_del_external_learn(struct net_bridge_fdb_entry *f)
+{
+	struct switchdev_obj obj = {
+		.id = SWITCHDEV_OBJ_PORT_FDB,
+		.u.fdb = {
+			.addr = f->addr.addr,
+			.vid = f->vlan_id,
+		},
+	};
+
+	switchdev_port_obj_del(f->dst->dev, &obj);
+}
+
 static void fdb_delete(struct net_bridge *br, struct net_bridge_fdb_entry *f)
 {
 	if (f->is_static)
 		fdb_del_hw_addr(br, f->addr.addr);
 
+	if (f->added_by_external_learn)
+		fdb_del_external_learn(f);
+
 	hlist_del_rcu(&f->hlist);
 	fdb_notify(br, f, RTM_DELNEIGH);
 	call_rcu(&f->rcu, fdb_rcu_free);
-- 
1.7.10.4

Re: [PATCH net-next] bridge: del external_learned fdbs from device on flush or ageout

[Rami Rosen]

Hi,

You mention bridge doing ageing vs. device doing
ageing. AFAIK, there is no way to prevent a bridge from doing aging by
a sysfs entry. Do you think that preventing bridge aging via sysfs is
needed?

Regards,
Rami Rosen

Re: [PATCH net-next] bridge: del external_learned fdbs from device on flush or ageout

[Scott Feldman]

On Sun, Jun 14, 2015 at 3:14 PM, Rami Rosen <roszenrami@gmail.com> wrote:
> Hi,
>
> You mention bridge doing ageing vs. device doing
> ageing. AFAIK, there is no way to prevent a bridge from doing aging by
> a sysfs entry. Do you think that preventing bridge aging via sysfs is
> needed?

The topic has been discussed before, but not at the patch level, yet,
AFIAK.  I had this XXX comment in
Documentation/networking/switchdev.txt:

     XXX: how to turn off ageing in kernel on a per-port basis or
otherwise prevent the kernel from ageing out the FDB entry?

I think the preference would be to use netlink over sysfs.  If we made
this a per-port flag, we could add bool IFLA_BRPORT_AGEING flag (and
BR_AGEING) for IFLA_PROTINFO.

There is also the need to push the bridge's ageing timeout value down
to the device.  This could be done with switchdev attr, e.g.
SWITCHDEV_ATTR_AGEING_TIMEOUT.  (Maybe there is already netlink
plumbing to do this...need to check).

Are you going to work on it?  ;)

-scott

Re: [PATCH net-next] bridge: del external_learned fdbs from device on flush or ageout

[Rami Rosen]

Hi,
I will try to find time, will notify you if starting work on it ;)

Regards,
Rami Rosen

Re: [PATCH net-next] bridge: del external_learned fdbs from device on flush or ageout

[David Miller]

From: sfeldma@gmail.com
Date: Sun, 14 Jun 2015 11:33:11 -0700

> From: Scott Feldman <sfeldma@gmail.com>
> 
> We need to delete from offload the device externally learnded fdbs when any
> one of these events happen:
> 
> 1) Bridge ages out fdb.  (When bridge is doing ageing vs. device doing
> ageing.  If device is doing ageing, it would send SWITCHDEV_FDB_DEL
> directly).
> 
> 2) STP state change flushes fdbs on port.
> 
> 3) User uses sysfs interface to flush fdbs from bridge or bridge port:
> 
> 	echo 1 >/sys/class/net/BR_DEV/bridge/flush
> 	echo 1 >/sys/class/net/BR_PORT/brport/flush
> 
> 4) Offload driver send event SWITCHDEV_FDB_DEL to delete fdb entry.
> 
> For rocker, we can now get called to delete fdb entry in wait and nowait
> contexts, so set NOWAIT flag when deleting fdb entry.
> 
> Signed-off-by: Scott Feldman <sfeldma@gmail.com>

Applied, thanks Scott.