Re: [PATCH net-next v3 3/9] net: rswitch: Use build_skb() for RX

[Simon Horman <horms@kernel.org>]

On Mon, Dec 04, 2023 at 10:20:52AM +0900, Yoshihiro Shimoda wrote:
> If this hardware receives a jumbo frame like 2KiB or more, it will be
> split into multiple queues. In the near future, to support this, use
> build_skb() instead of netdev_alloc_skb_ip_align().
> 
> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>

...

>  static void rswitch_gwca_ts_queue_free(struct rswitch_private *priv)
> @@ -308,17 +308,19 @@ static int rswitch_gwca_queue_alloc(struct net_device *ndev,
>  	gq->ring_size = ring_size;
>  	gq->ndev = ndev;
>  
> -	gq->skbs = kcalloc(gq->ring_size, sizeof(*gq->skbs), GFP_KERNEL);
> -	if (!gq->skbs)
> -		return -ENOMEM;
> -
>  	if (!dir_tx) {
> -		rswitch_gwca_queue_alloc_skb(gq, 0, gq->ring_size);
> +		gq->rx_bufs = kcalloc(gq->ring_size, sizeof(*gq->rx_bufs), GFP_KERNEL);
> +		if (!gq->rx_bufs)
> +			goto out;

Hi Shimoda-san,

there is no need to re-spin because of this,
but I have some commends on error handling.

I think that for consistency this can just return -ENOMEM.
Or alternatively, perhaps 'goto out' can be used for the (!gq->skbs)
condition below.

> +		rswitch_gwca_queue_alloc_rx_buf(gq, 0, gq->ring_size);

Not strictly related to this patch, but should
the return value of rswitch_gwca_queue_alloc_rx_buf be checked?

>  
>  		gq->rx_ring = dma_alloc_coherent(ndev->dev.parent,
>  						 sizeof(struct rswitch_ext_ts_desc) *
>  						 (gq->ring_size + 1), &gq->ring_dma, GFP_KERNEL);
>  	} else {
> +		gq->skbs = kcalloc(gq->ring_size, sizeof(*gq->skbs), GFP_KERNEL);
> +		if (!gq->skbs)
> +			return -ENOMEM;
>  		gq->tx_ring = dma_alloc_coherent(ndev->dev.parent,
>  						 sizeof(struct rswitch_ext_desc) *
>  						 (gq->ring_size + 1), &gq->ring_dma, GFP_KERNEL);

...