Commit bd5afca1 authored by Lorenzo Bianconi's avatar Lorenzo Bianconi Committed by Paolo Abeni
Browse files

net: airoha: Take into account out-of-order tx completions in airoha_dev_xmit() 



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: 23020f04 ("net: airoha: Introduce ethernet support for EN7581 SoC")
Suggested-by: default avatarSimon Horman <horms@kernel.org>
Signed-off-by: default avatarLorenzo Bianconi <lorenzo@kernel.org>
Reviewed-by: default avatarSimon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20251012-airoha-tx-busy-queue-v2-1-a600b08bab2d@kernel.org


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent 295ce1eb

drivers/net/ethernet/airoha/airoha_eth.c

+15 −1
Original line number Diff line number Diff line
@@ -1873,6 +1873,20 @@ static u32 airoha_get_dsa_tag(struct sk_buff *skb, struct net_device *dev) 
#endif

}



static bool airoha_dev_tx_queue_busy(struct airoha_queue *q, u32 nr_frags)

{

	u32 tail = q->tail <= q->head ? q->tail + q->ndesc : q->tail;

	u32 index = q->head + nr_frags;



	/* 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 >= tail;

}



static netdev_tx_t airoha_dev_xmit(struct sk_buff *skb,

				   struct net_device *dev)

{
@@ -1926,7 +1940,7 @@ 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_tx_queue_busy(q, nr_frags)) {

		/* not enough space in the queue */

		netif_tx_stop_queue(txq);

		spin_unlock_bh(&q->lock);