[PATCH v2 net-next 9/9] net: dsa: netc: implement dynamic FDB entry ageing
wei.fang at oss.nxp.com
wei.fang at oss.nxp.com
Tue Jun 2 00:23:13 PDT 2026
From: Wei Fang <wei.fang at nxp.com>
The NETC switch does not age out dynamic FDB entries automatically.
Without software management, stale entries persist after topology
changes and cause incorrect forwarding.
Add a delayed work that periodically removes entries that have not been
refreshed within the specified cycles. The effective aging time is:
ageing_time = fdbt_ageing_delay * 100
Default values are 3s interval and 100 cycles (300s total), matching
the IEEE 802.1Q default ageing time. The work starts when the first
port joins a bridge (tracked via br_cnt) and is cancelled when the
last port leaves. All FDB operations are serialized under fdbt_lock.
When a port leaves the bridge, its dynamic FDB entries are flushed
right away in port_bridge_leave(), without waiting for the ageing
cycle. Additionally, when a link down event is detected on a port,
netc_mac_link_down() will also clear the port's dynamic FDB entries
via netc_port_remove_dynamic_entries(). Non-bridge ports have no
dynamic FDB entries, so this call is always safe.
Implement set_ageing_time and port_fast_age DSA operations to allow
the bridge layer to reconfigure aging parameters and trigger per-port
flushes on demand.
Signed-off-by: Wei Fang <wei.fang at nxp.com>
---
drivers/net/dsa/netc/netc_main.c | 90 ++++++++++++++++++++++++++++++
drivers/net/dsa/netc/netc_switch.h | 7 +++
2 files changed, 97 insertions(+)
diff --git a/drivers/net/dsa/netc/netc_main.c b/drivers/net/dsa/netc/netc_main.c
index 5b58ce06beb8..3737a852cafc 100644
--- a/drivers/net/dsa/netc/netc_main.c
+++ b/drivers/net/dsa/netc/netc_main.c
@@ -447,6 +447,25 @@ static void netc_free_ntmp_user(struct netc_switch *priv)
netc_free_ntmp_bitmaps(priv);
}
+static void netc_clean_fdbt_ageing_entries(struct work_struct *work)
+{
+ struct delayed_work *dwork = to_delayed_work(work);
+ struct netc_switch *priv;
+
+ priv = container_of(dwork, struct netc_switch, fdbt_ageing_work);
+
+ /* Update the activity element in FDB table */
+ mutex_lock(&priv->fdbt_lock);
+ ntmp_fdbt_update_activity_element(&priv->ntmp);
+ /* Delete the ageing entries after the activity element is updated */
+ ntmp_fdbt_delete_ageing_entries(&priv->ntmp, NETC_FDBT_AGEING_THRESH);
+ mutex_unlock(&priv->fdbt_lock);
+
+ if (atomic_read(&priv->br_cnt))
+ schedule_delayed_work(&priv->fdbt_ageing_work,
+ READ_ONCE(priv->fdbt_ageing_delay));
+}
+
static void netc_switch_dos_default_config(struct netc_switch *priv)
{
struct netc_switch_regs *regs = &priv->regs;
@@ -861,6 +880,10 @@ static int netc_setup(struct dsa_switch *ds)
INIT_HLIST_HEAD(&priv->fdb_list);
mutex_init(&priv->fdbt_lock);
+ priv->fdbt_ageing_delay = NETC_FDBT_AGEING_DELAY;
+ atomic_set(&priv->br_cnt, 0);
+ INIT_DELAYED_WORK(&priv->fdbt_ageing_work,
+ netc_clean_fdbt_ageing_entries);
INIT_HLIST_HEAD(&priv->vlan_list);
mutex_init(&priv->vft_lock);
@@ -925,6 +948,7 @@ static void netc_teardown(struct dsa_switch *ds)
{
struct netc_switch *priv = ds->priv;
+ disable_delayed_work_sync(&priv->fdbt_ageing_work);
netc_destroy_all_lists(priv);
netc_free_host_flood_rules(priv);
netc_free_ntmp_user(priv);
@@ -1948,6 +1972,7 @@ static int netc_port_bridge_join(struct dsa_switch *ds, int port,
struct netlink_ext_ack *extack)
{
struct netc_port *np = NETC_PORT(ds, port);
+ struct netc_switch *priv = ds->priv;
u16 vlan_unaware_pvid;
int err;
@@ -1974,20 +1999,42 @@ static int netc_port_bridge_join(struct dsa_switch *ds, int port,
np->host_flood = NULL;
netc_port_wr(np, NETC_PIPFCR, 0);
+ if (atomic_inc_return(&priv->br_cnt) == 1)
+ schedule_delayed_work(&priv->fdbt_ageing_work,
+ READ_ONCE(priv->fdbt_ageing_delay));
+
return 0;
}
+static void netc_port_remove_dynamic_entries(struct netc_port *np)
+{
+ struct netc_switch *priv = np->switch_priv;
+
+ /* Return if the port is not available */
+ if (!np->dp)
+ return;
+
+ mutex_lock(&priv->fdbt_lock);
+ ntmp_fdbt_delete_port_dynamic_entries(&priv->ntmp, np->dp->index);
+ mutex_unlock(&priv->fdbt_lock);
+}
+
static void netc_port_bridge_leave(struct dsa_switch *ds, int port,
struct dsa_bridge bridge)
{
struct netc_port *np = NETC_PORT(ds, port);
struct net_device *ndev = np->dp->user;
+ struct netc_switch *priv = ds->priv;
u16 vlan_unaware_pvid;
bool mc, uc;
netc_port_set_mlo(np, MLO_DISABLE);
netc_port_set_pvid(np, NETC_STANDALONE_PVID);
+ if (atomic_dec_and_test(&priv->br_cnt))
+ cancel_delayed_work_sync(&priv->fdbt_ageing_work);
+
+ netc_port_remove_dynamic_entries(np);
uc = ndev->flags & IFF_PROMISC;
mc = ndev->flags & (IFF_PROMISC | IFF_ALLMULTI);
@@ -2007,6 +2054,44 @@ static void netc_port_bridge_leave(struct dsa_switch *ds, int port,
netc_port_del_vlan_entry(np, vlan_unaware_pvid);
}
+static int netc_set_ageing_time(struct dsa_switch *ds, unsigned int msecs)
+{
+ struct netc_switch *priv = ds->priv;
+ unsigned long delay_jiffies;
+
+ /* The dynamic FDB entry is deleted when its activity counter reaches
+ * NETC_FDBT_AGEING_THRESH (100). Each delayed_work tick increments
+ * the counter by 1 if the entry is inactive.
+ *
+ * Therefore:
+ * msecs (ms) = NETC_FDBT_AGEING_THRESH * delay_ms (ms)
+ * delay_ms = msecs / NETC_FDBT_AGEING_THRESH
+ * delay_jiffies = (delay_ms / 1000) * HZ
+ * = (msecs * HZ) / (1000 * NETC_FDBT_AGEING_THRESH)
+ *
+ * Use DIV_ROUND_CLOSEST_ULL to perform a single nearest-jiffy
+ * rounding, avoiding the two-step rounding error of the intermediate
+ * delay_ms approach.
+ * Maximum error = +/-0.5 jiffy * 100 = 50000/HZ ms.
+ */
+ delay_jiffies = DIV_ROUND_CLOSEST_ULL((u64)msecs * HZ,
+ 1000 * NETC_FDBT_AGEING_THRESH);
+ WRITE_ONCE(priv->fdbt_ageing_delay, delay_jiffies);
+
+ if (atomic_read(&priv->br_cnt))
+ mod_delayed_work(system_percpu_wq, &priv->fdbt_ageing_work,
+ READ_ONCE(priv->fdbt_ageing_delay));
+
+ return 0;
+}
+
+static void netc_port_fast_age(struct dsa_switch *ds, int port)
+{
+ struct netc_port *np = NETC_PORT(ds, port);
+
+ netc_port_remove_dynamic_entries(np);
+}
+
static void netc_phylink_get_caps(struct dsa_switch *ds, int port,
struct phylink_config *config)
{
@@ -2261,6 +2346,7 @@ static void netc_mac_link_down(struct phylink_config *config,
np = NETC_PORT(dp->ds, dp->index);
netc_port_mac_rx_graceful_stop(np);
netc_port_mac_tx_graceful_stop(np);
+ netc_port_remove_dynamic_entries(np);
}
static const struct phylink_mac_ops netc_phylink_mac_ops = {
@@ -2290,6 +2376,8 @@ static const struct dsa_switch_ops netc_switch_ops = {
.port_vlan_del = netc_port_vlan_del,
.port_bridge_join = netc_port_bridge_join,
.port_bridge_leave = netc_port_bridge_leave,
+ .set_ageing_time = netc_set_ageing_time,
+ .port_fast_age = netc_port_fast_age,
.get_pause_stats = netc_port_get_pause_stats,
.get_rmon_stats = netc_port_get_rmon_stats,
.get_eth_ctrl_stats = netc_port_get_eth_ctrl_stats,
@@ -2338,6 +2426,8 @@ static int netc_switch_probe(struct pci_dev *pdev,
ds->phylink_mac_ops = &netc_phylink_mac_ops;
ds->fdb_isolation = true;
ds->max_num_bridges = priv->info->num_ports - 1;
+ ds->ageing_time_min = 1000;
+ ds->ageing_time_max = U32_MAX;
ds->priv = priv;
priv->ds = ds;
diff --git a/drivers/net/dsa/netc/netc_switch.h b/drivers/net/dsa/netc/netc_switch.h
index 982c8d3a3fbf..4abef8b383bd 100644
--- a/drivers/net/dsa/netc/netc_switch.h
+++ b/drivers/net/dsa/netc/netc_switch.h
@@ -50,6 +50,9 @@
/* PAUSE refresh threshold: send refresh when timer reaches this value */
#define NETC_PAUSE_THRESH 0x7FFF
+#define NETC_FDBT_AGEING_DELAY (3 * HZ)
+#define NETC_FDBT_AGEING_THRESH 100
+
struct netc_switch;
struct netc_switch_info {
@@ -124,6 +127,10 @@ struct netc_switch {
struct ntmp_user ntmp;
struct hlist_head fdb_list;
struct mutex fdbt_lock; /* FDB table lock */
+ struct delayed_work fdbt_ageing_work;
+ /* (fdbt_ageing_delay * ageing_act_cnt) is ageing time */
+ unsigned long fdbt_ageing_delay;
+ atomic_t br_cnt;
struct hlist_head vlan_list;
struct mutex vft_lock; /* VLAN filter table lock */
--
2.34.1
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