[PATCH net] net: airoha: fix HTB class modification offload

[Wayen Yan <win847@gmail.com>]

HTB core does not populate parent_classid for TC_HTB_NODE_MODIFY.
Airoha currently checks parent_classid against TC_HTB_CLASSID_ROOT
in a helper shared by both TC_HTB_LEAF_ALLOC_QUEUE and
TC_HTB_NODE_MODIFY. Since the modify path leaves parent_classid as
zero, the check always fails and changing parameters of an already
offloaded HTB class is rejected with -EINVAL.

Move the root-parent check into the allocation path and validate
modify requests using the per-netdev QoS channel bitmap, consistent
with the delete and query paths.

Fixes: ef1ca9271313 ("net: airoha: Add sched HTB offload support")
Signed-off-by: Wayen Yan <win847@gmail.com>
---
 drivers/net/ethernet/airoha/airoha_eth.c | 32 +++++++++++++++++-------
 1 file changed, 23 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/airoha/airoha_eth.c b/drivers/net/ethernet/airoha/airoha_eth.c
index 59001fd4b6f7..8e4e79c1e4c2 100644
--- a/drivers/net/ethernet/airoha/airoha_eth.c
+++ b/drivers/net/ethernet/airoha/airoha_eth.c
@@ -2766,18 +2766,13 @@ static int airoha_qdma_set_tx_rate_limit(struct net_device *netdev,
 	return 0;
 }
 
-static int airoha_tc_htb_modify_queue(struct net_device *dev,
-				      struct tc_htb_qopt_offload *opt)
+static int airoha_tc_htb_set_rate(struct net_device *dev,
+				  struct tc_htb_qopt_offload *opt,
+				  u32 channel)
 {
-	u32 channel = TC_H_MIN(opt->classid) % AIROHA_NUM_QOS_CHANNELS;
 	u32 rate = div_u64(opt->rate, 1000) << 3; /* kbps */
 	int err;
 
-	if (opt->parent_classid != TC_HTB_CLASSID_ROOT) {
-		NL_SET_ERR_MSG_MOD(opt->extack, "invalid parent classid");
-		return -EINVAL;
-	}
-
 	err = airoha_qdma_set_tx_rate_limit(dev, channel, rate, opt->quantum);
 	if (err)
 		NL_SET_ERR_MSG_MOD(opt->extack,
@@ -2786,6 +2781,20 @@ static int airoha_tc_htb_modify_queue(struct net_device *dev,
 	return err;
 }
 
+static int airoha_tc_htb_modify_queue(struct net_device *netdev,
+				      struct tc_htb_qopt_offload *opt)
+{
+	u32 channel = TC_H_MIN(opt->classid) % AIROHA_NUM_QOS_CHANNELS;
+	struct airoha_gdm_dev *dev = netdev_priv(netdev);
+
+	if (!test_bit(channel, dev->qos_sq_bmap)) {
+		NL_SET_ERR_MSG_MOD(opt->extack, "invalid queue id");
+		return -EINVAL;
+	}
+
+	return airoha_tc_htb_set_rate(netdev, opt, channel);
+}
+
 static int airoha_tc_htb_alloc_leaf_queue(struct net_device *netdev,
 					  struct tc_htb_qopt_offload *opt)
 {
@@ -2794,6 +2803,11 @@ static int airoha_tc_htb_alloc_leaf_queue(struct net_device *netdev,
 	struct airoha_gdm_dev *dev = netdev_priv(netdev);
 	struct airoha_qdma *qdma = dev->qdma;
 
+	if (opt->parent_classid != TC_HTB_CLASSID_ROOT) {
+		NL_SET_ERR_MSG_MOD(opt->extack, "invalid parent classid");
+		return -EINVAL;
+	}
+
 	/* Here we need to check the requested QDMA channel is not already
 	 * in use by another net_device running on the same QDMA block.
 	 */
@@ -2803,7 +2817,7 @@ static int airoha_tc_htb_alloc_leaf_queue(struct net_device *netdev,
 		return -EBUSY;
 	}
 
-	err = airoha_tc_htb_modify_queue(netdev, opt);
+	err = airoha_tc_htb_set_rate(netdev, opt, channel);
 	if (err)
 		goto error;
 
-- 
2.51.0