[EXTERNAL] Re: [PATCH v12 06/10] net: ti: icssg-prueth: Add ICSSG ethernet driver

[Md Danish Anwar]

Hi Jakub,

On 29/07/23 5:54 am, Jakub Kicinski wrote:
> On Thu, 27 Jul 2023 16:58:23 +0530 MD Danish Anwar wrote:
>> +static int emac_tx_complete_packets(struct prueth_emac *emac, int chn,
>> +				    int budget)
>> +{
>> +	struct net_device *ndev = emac->ndev;
>> +	struct cppi5_host_desc_t *desc_tx;
>> +	struct netdev_queue *netif_txq;
>> +	struct prueth_tx_chn *tx_chn;
>> +	unsigned int total_bytes = 0;
>> +	struct sk_buff *skb;
>> +	dma_addr_t desc_dma;
>> +	int res, num_tx = 0;
>> +	void **swdata;
>> +
>> +	tx_chn = &emac->tx_chns[chn];
>> +
>> +	while (budget) {
>> +		res = k3_udma_glue_pop_tx_chn(tx_chn->tx_chn, &desc_dma);
>> +		if (res == -ENODATA)
>> +			break;
> 
> You shouldn't limit the number of serviced packets to budget for Tx
> NAPI.
> 
> https://docs.kernel.org/next/networking/napi.html#driver-api
> 
>> +	skb->dev = ndev;
>> +	if (!netif_running(skb->dev)) {
>> +		dev_kfree_skb_any(skb);
>> +		return 0;
>> +	}
> 
> why do you check if the interface is running?
> If a packet arrives, it means the interface is running..
> 

Sure, I will drop this if condition.

>> +drop_free_descs:
>> +	prueth_xmit_free(tx_chn, first_desc);
>> +drop_stop_q:
>> +	netif_tx_stop_queue(netif_txq);
> 
> Do not stop the queue on DMA errors. If the queue is empty nothing
> will wake it up. Queue should only be stopped based on occupancy.
> 

Sure, I will try to make sure we only stop queue based on occupancy.

>> +	dev_kfree_skb_any(skb);
>> +
>> +	/* error */
>> +	ndev->stats.tx_dropped++;
>> +	netdev_err(ndev, "tx: error: %d\n", ret);
>> +
>> +	return ret;

-- 
Thanks and Regards,
Danish.