[PATCH net] net: airoha: fix ETS channel derivation in airoha_tc_setup_qdisc_ets()

[PATCH net] net: airoha: fix ETS channel derivation in airoha_tc_setup_qdisc_ets()

[Lorenzo Bianconi]

Derive the hardware QoS channel from opt->parent instead of opt->handle
in airoha_tc_setup_qdisc_ets(). The ETS qdisc handle is either
user-specified or auto-allocated by qdisc_alloc_handle() and bears no
relation to the HTB leaf classid that identifies the hardware channel.
HTB derives the channel from TC_H_MIN(opt->classid), and ETS is always
attached as a child of an HTB leaf, so its opt->parent matches that
classid. Using opt->handle instead can cause two ETS qdiscs on different
HTB leaves to collide on the same hardware channel, corrupting scheduler
configuration and stats.

Fixes: 20bf7d07c956 ("net: airoha: Add sched ETS offload support")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
 drivers/net/ethernet/airoha/airoha_eth.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/airoha/airoha_eth.c b/drivers/net/ethernet/airoha/airoha_eth.c
index 59001fd4b6f7..fac2aaefffff 100644
--- a/drivers/net/ethernet/airoha/airoha_eth.c
+++ b/drivers/net/ethernet/airoha/airoha_eth.c
@@ -2504,8 +2504,7 @@ static int airoha_tc_setup_qdisc_ets(struct net_device *dev,
 	if (opt->parent == TC_H_ROOT)
 		return -EINVAL;
 
-	channel = TC_H_MAJ(opt->handle) >> 16;
-	channel = channel % AIROHA_NUM_QOS_CHANNELS;
+	channel = TC_H_MIN(opt->parent) % AIROHA_NUM_QOS_CHANNELS;
 
 	switch (opt->command) {
 	case TC_ETS_REPLACE:

---
base-commit: d6456743424721a837e1509b912f362caaeecd97
change-id: 20260704-airoha-ets-handle-fix-6c166de3d396

Best regards,
-- 
Lorenzo Bianconi <lorenzo@kernel.org>

Re: [PATCH net] net: airoha: fix ETS channel derivation in airoha_tc_setup_qdisc_ets()

[Simon Horman]

On Sat, Jul 04, 2026 at 04:21:38PM +0200, Lorenzo Bianconi wrote:
> Derive the hardware QoS channel from opt->parent instead of opt->handle
> in airoha_tc_setup_qdisc_ets(). The ETS qdisc handle is either
> user-specified or auto-allocated by qdisc_alloc_handle() and bears no
> relation to the HTB leaf classid that identifies the hardware channel.
> HTB derives the channel from TC_H_MIN(opt->classid), and ETS is always
> attached as a child of an HTB leaf, so its opt->parent matches that
> classid. Using opt->handle instead can cause two ETS qdiscs on different
> HTB leaves to collide on the same hardware channel, corrupting scheduler
> configuration and stats.
> 
> Fixes: 20bf7d07c956 ("net: airoha: Add sched ETS offload support")
> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>

Reviewed-by: Simon Horman <horms@kernel.org>