Re: [PATCH net-next 1/2] net: airoha: Add the capability to consume out-of-order DMA tx descriptors

[Jakub Kicinski <kuba@kernel.org>]

On Mon, 03 Nov 2025 11:27:55 +0100 Lorenzo Bianconi wrote:
> +		__list_del_entry(&e->list);
> +		list_add_tail(&e->list, &tx_list);

list_move_tail()

> +		e->skb = i ? NULL : skb;
> +		e->dma_addr = addr;
> +		e->dma_len = len;
> +
> +		e = list_first_entry(&q->tx_list, struct airoha_queue_entry,
> +				     list);
> +		index = e - q->entry;
>  
>  		val = FIELD_PREP(QDMA_DESC_LEN_MASK, len);
>  		if (i < nr_frags - 1)

> @@ -2029,10 +2020,14 @@ static netdev_tx_t airoha_dev_xmit(struct sk_buff *skb,
>  	return NETDEV_TX_OK;
>  
>  error_unmap:
> -	for (i--; i >= 0; i--) {
> -		index = (q->head + i) % q->ndesc;
> -		dma_unmap_single(dev->dev.parent, q->entry[index].dma_addr,
> -				 q->entry[index].dma_len, DMA_TO_DEVICE);
> +	while (!list_empty(&tx_list)) {
> +		e = list_first_entry(&tx_list, struct airoha_queue_entry,
> +				     list);
> +		__list_del_entry(&e->list);
> +		dma_unmap_single(dev->dev.parent, e->dma_addr, e->dma_len,
> +				 DMA_TO_DEVICE);
> +		e->dma_addr = 0;
> +		list_add_tail(&e->list, &q->tx_list);

and here