From e824e40d0e841fab66ab7897d6c7b14dc81c66a7 Mon Sep 17 00:00:00 2001 From: Daniel Golle Date: Thu, 14 May 2026 15:04:21 +0100 Subject: [PATCH] net: dsa: mt7530: fix FDB entries not aging out with short timeout The DSA forwarding selftests bridge_vlan_aware.sh and bridge_vlan_unaware.sh configure the bridge with ageing_time set to LOW_AGEING_TIME (1000 centiseconds, i.e. 10 seconds) and then run learning_test() in lib.sh, which expects a learned FDB entry to be removed after ageing_time + 10 seconds. On MT7530/MT7531 the entry persisted past the deadline and the "Found FDB record when should not" assertion failed. With msecs=10000, the algorithm in mt7530_set_ageing_time() finds AGE_CNT=0 and AGE_UNIT=9 as the first exact match (starting the search from tmp_age_count=0). The per-entry aging counter is initialized to AGE_CNT when a MAC address is learned, so with AGE_CNT=0 new entries start with a counter value of 0, which the hardware treats as "already aged" and never removes, effectively disabling aging. Fix this by starting the search from tmp_age_count=1 to ensure entries always have a non-zero initial aging counter. For a 10-second ageing time this yields AGE_CNT=1 and AGE_UNIT=4 instead: the timer ticks every 5 seconds and entries are removed after 2 ticks. Starting the search at AGE_CNT=1 raises the minimum representable ageing time from 1 to 2 seconds. Without bounds, a stale ageing_time of 1 second would now make the loop fall through without setting age_count and age_unit, leaving them uninitialized when written to the MT7530_AAC hardware register. Set ds->ageing_time_min and ds->ageing_time_max so the DSA core validates the range before the callback is invoked, and drop the now-redundant range check from mt7530_set_ageing_time(). Fixes: ea6d5c924e39 ("net: dsa: mt7530: support setting ageing time") Signed-off-by: Daniel Golle Link: https://patch.msgid.link/7788ded12dc07b1bce329ec35fa70f4b45f3f9b7.1778766629.git.daniel@makrotopia.org Signed-off-by: Paolo Abeni --- drivers/net/dsa/mt7530.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c index 44d670904ad8..cd311dfd3600 100644 --- a/drivers/net/dsa/mt7530.c +++ b/drivers/net/dsa/mt7530.c @@ -1023,12 +1023,16 @@ mt7530_set_ageing_time(struct dsa_switch *ds, unsigned int msecs) unsigned int age_count; unsigned int age_unit; - /* Applied timer is (AGE_CNT + 1) * (AGE_UNIT + 1) seconds */ - if (secs < 1 || secs > (AGE_CNT_MAX + 1) * (AGE_UNIT_MAX + 1)) - return -ERANGE; - - /* iterate through all possible age_count to find the closest pair */ - for (tmp_age_count = 0; tmp_age_count <= AGE_CNT_MAX; ++tmp_age_count) { + /* Applied timer is (AGE_CNT + 1) * (AGE_UNIT + 1) seconds. + * The DSA core has already validated the range using + * ds->ageing_time_min and ds->ageing_time_max. + * + * Iterate through all possible age_count values to find the closest + * pair. Start from 1 because the per-entry aging counter is + * initialized to AGE_CNT and a value of 0 means the entry will + * never be aged out. + */ + for (tmp_age_count = 1; tmp_age_count <= AGE_CNT_MAX; ++tmp_age_count) { unsigned int tmp_age_unit = secs / (tmp_age_count + 1) - 1; if (tmp_age_unit <= AGE_UNIT_MAX) { @@ -2428,6 +2432,8 @@ mt7530_setup(struct dsa_switch *ds) ds->assisted_learning_on_cpu_port = true; ds->mtu_enforcement_ingress = true; + ds->ageing_time_min = 2 * 1000; + ds->ageing_time_max = (AGE_CNT_MAX + 1) * (AGE_UNIT_MAX + 1) * 1000; if (priv->id == ID_MT7530) { regulator_set_voltage(priv->core_pwr, 1000000, 1000000); @@ -2617,6 +2623,8 @@ mt7531_setup_common(struct dsa_switch *ds) ds->assisted_learning_on_cpu_port = true; ds->mtu_enforcement_ingress = true; + ds->ageing_time_min = 2 * 1000; + ds->ageing_time_max = (AGE_CNT_MAX + 1) * (AGE_UNIT_MAX + 1) * 1000; mt753x_trap_frames(priv);