Re: [PATCH v6 net-next 2/2] net: airoha: Introduce ethernet support for EN7581 SoC

[Lorenzo Bianconi <lorenzo@kernel.org>]

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> > +static int airoha_qdma_init_rx_queue(struct airoha_eth *eth,
> > +				     struct airoha_queue *q, int ndesc)
> > +{
> > +	struct page_pool_params pp_params = {
> > +		.order = 0,
> > +		.pool_size = 256,
> > +		.flags = PP_FLAG_DMA_MAP | PP_FLAG_DMA_SYNC_DEV,
> > +		.dma_dir = DMA_FROM_DEVICE,
> > +		.max_len = PAGE_SIZE,
> > +		.nid = NUMA_NO_NODE,
> > +		.dev = eth->dev,
> > +		.napi = &q->napi,
> > +	};
> 
> I think you can make this const.

ack

> 
> > +static int airoha_alloc_gdm_port(struct airoha_eth *eth, struct device_node *np)
> > +{
> 
> > +	port = netdev_priv(dev);
> > +	mutex_init(&port->stats.mutex);
> > +	port->dev = dev;
> > +	port->eth = eth;
> > +	port->id = id;
> > +
> > +	err = register_netdev(dev);
> > +	if (err)
> > +		return err;
> > +
> > +	eth->ports[index] = port;
> 
> eth->ports[index] appears to be used in
> airoha_qdma_rx_process(). There is a small race condition here, since
> the interface could be in use before register_netdev() returns,
> e.g. NFS root. It would be better to do the assignment before
> registering the interface.

actually I check eth->ports[] is not NULL before accessing it in
airoha_qdma_rx_process():

	p = airoha_qdma_get_gdm_port(eth, desc);
	if (p < 0 || !eth->ports[p]) {
		...
	}

Moreover, in airoha_alloc_gdm_port(), I set eth->ports[index] pointer just if
register_netdev() is successful in order to avoid to call unregister_netdev()
on an not-registered net_device in the airoha_probe() error path. I guess we can
even check reg_state for this:

	for (i = 0; i < ARRAY_SIZE(eth->ports); i++) {
		...
		if (dev->reg_state == NETREG_REGISTERED)
			unregister_netdev(dev);
	}

What do you prefer?

Regards,
Lorenzo

> 
> These are quite minor, so please add to the next version:
> 
> Reviewed-by: Andrew Lunn <andrew@lunn.ch>
> 
>     Andrew
> 
> ---
> pw-bot: cr

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