Completion napi can free out-of-order tx descriptors if hw QoS is enabled and packets with different priority are queued to same DMA ring. Take into account possible out-of-order reports checking if the tx queue is full using circular buffer head/tail pointer instead of the number of queued packets. Fixes: 23020f0493270 ("net: airoha: Introduce ethernet support for EN7581 SoC") Signed-off-by: Lorenzo Bianconi --- drivers/net/ethernet/airoha/airoha_eth.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/airoha/airoha_eth.c b/drivers/net/ethernet/airoha/airoha_eth.c index 833dd911980b3f698bd7e5f9fd9e2ce131dd5222..5e2ff52dba03a7323141fe9860fba52806279bd0 100644 --- a/drivers/net/ethernet/airoha/airoha_eth.c +++ b/drivers/net/ethernet/airoha/airoha_eth.c @@ -1873,6 +1873,19 @@ static u32 airoha_get_dsa_tag(struct sk_buff *skb, struct net_device *dev) #endif } +static bool airoha_dev_is_tx_busy(struct airoha_queue *q, u32 nr_frags) +{ + u16 index = (q->head + nr_frags) % q->ndesc; + + /* completion napi can free out-of-order tx descriptors if hw QoS is + * enabled and packets with different priorities are queued to the same + * DMA ring. Take into account possible out-of-order reports checking + * if the tx queue is full using circular buffer head/tail pointers + * instead of the number of queued packets. + */ + return index >= q->tail && (q->head < q->tail || q->head > index); +} + static netdev_tx_t airoha_dev_xmit(struct sk_buff *skb, struct net_device *dev) { @@ -1926,7 +1939,7 @@ static netdev_tx_t airoha_dev_xmit(struct sk_buff *skb, txq = netdev_get_tx_queue(dev, qid); nr_frags = 1 + skb_shinfo(skb)->nr_frags; - if (q->queued + nr_frags > q->ndesc) { + if (airoha_dev_is_tx_busy(q, nr_frags)) { /* not enough space in the queue */ netif_tx_stop_queue(txq); spin_unlock_bh(&q->lock); --- base-commit: 18a7e218cfcdca6666e1f7356533e4c988780b57 change-id: 20251010-airoha-tx-busy-queue-bdf11cec83ed Best regards, -- Lorenzo Bianconi