Re: [PATCH] net: fec: Keep device numbering consistent with datasheet

[David Miller]

From: Stefan Riedmueller <s.riedmueller@xxxxxxxxx>
Date: Wed, 23 Sep 2020 16:25:28 +0200

> From: Christian Hemp <c.hemp@xxxxxxxxx>
> 
> Make use of device tree alias for device enumeration to keep the device
> order consistent with the naming in the datasheet.
> 
> Otherwise for the i.MX 6UL/ULL the ENET1 interface is enumerated as eth1
> and ENET2 as eth0.
> 
> Signed-off-by: Christian Hemp <c.hemp@xxxxxxxxx>
> Signed-off-by: Stefan Riedmueller <s.riedmueller@xxxxxxxxx>

Device naming and ordering for networking devices was never, ever,
guaranteed.

Use udev or similar.

> @@ -3691,6 +3692,10 @@ fec_probe(struct platform_device *pdev)
>  
>  	ndev->max_mtu = PKT_MAXBUF_SIZE - ETH_HLEN - ETH_FCS_LEN;
>  
> +	eth_id = of_alias_get_id(pdev->dev.of_node, "ethernet");
> +	if (eth_id >= 0)
> +		sprintf(ndev->name, "eth%d", eth_id);

You can't ever just write into ndev->name, what if another networking
device is already using that name?

This change is incorrect on many levels.