[PATCH net] net: airoha: stop net_device TX queue before updating CPU index

Lorenzo Bianconi
2026-04-21T06:43:24Z

Currently, airoha_eth driver updates the CPU index register prior of
verifying whether the number of free descriptors has fallen below the
threshold.
Move net_device TX queue length check before updating the TX CPU index
in order to update TX CPU index even if there are more packets to be
transmitted but the net_device TX queue is going to be stopped
accounting the inflight packets.

Fixes: 1d304174106c ("net: airoha: Implement BQL support")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
drivers/net/ethernet/airoha/airoha_eth.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/airoha/airoha_eth.c b/drivers/net/ethernet/airoha/airoha_eth.c
index 19f67c7dd8e1..5d327237e274 100644
--- a/drivers/net/ethernet/airoha/airoha_eth.c
+++ b/drivers/net/ethernet/airoha/airoha_eth.c
@@ -2058,17 +2058,16 @@ static netdev_tx_t airoha_dev_xmit(struct sk_buff *skb,

skb_tx_timestamp(skb);
netdev_tx_sent_queue(txq, skb->len);
+ if (q->ndesc - q->queued < q->free_thr) {
+ netif_tx_stop_queue(txq);
+ q->txq_stopped = true;
+ }

if (netif_xmit_stopped(txq) || !netdev_xmit_more())
airoha_qdma_rmw(qdma, REG_TX_CPU_IDX(qid),
TX_RING_CPU_IDX_MASK,
FIELD_PREP(TX_RING_CPU_IDX_MASK, index));

- if (q->ndesc - q->queued < q->free_thr) {
- netif_tx_stop_queue(txq);
- q->txq_stopped = true;
- }
-
spin_unlock_bh(&q->lock);

return NETDEV_TX_OK;

---
base-commit: a663bac71a2f0b3ac6c373168ca57b2a6e6381aa
change-id: 20260421-airoha-xmit-stop-condition-344dc0292a19

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