# Re: \[PATCH net-next v2 1/4\] net: mdio: Introduce a regmap-based mdio driver

- From: Russell King (Oracle) \<linux@armlinux.org.uk\>
- Date: 2023-05-25 11:11:59 
- List: netdev
- Page: https://ratatoskr.run/netdev/2023/05/2209779
- Thread: https://ratatoskr.run/netdev/2023/05/2209714/t.md

```text
On Thu, May 25, 2023 at 12:11:23PM +0200, Maxime Chevallier wrote:
> +struct mii_bus *devm_mdio_regmap_register(struct device *dev,
> +					  const struct mdio_regmap_config *config)
> +{
> +	struct mdio_regmap_config *mrc;
> +	struct mii_bus *mii;
> +	int rc;
> +
> +	if (!config->parent)
> +		return ERR_PTR(-EINVAL);
> +
> +	mii = devm_mdiobus_alloc_size(config->parent, sizeof(*mrc));
> +	if (!mii)
> +		return ERR_PTR(-ENOMEM);
> +
> +	mrc = mii->priv;
> +	memcpy(mrc, config, sizeof(*mrc));
> +
> +	mrc->regmap = config->regmap;
> +	mrc->valid_addr = config->valid_addr;

You have just memcpy'd everything from config into mrc. Doesn't this
already include "regmap" and "valid_addr" ?

However, these are the only two things used, so does it really make
sense to allocate the full mdio_regmap_config structure, or would a
smaller data structure (of one pointer and one u8) be more appropriate?

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```