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

- From: Maxime Chevallier \<maxime.chevallier@bootlin.com\>
- Date: 2023-05-25 12:41:34 
- List: netdev
- Page: https://ratatoskr.run/netdev/2023/05/2209864
- Thread: https://ratatoskr.run/netdev/2023/05/2209714/t.md

```text
Hello Russell,

On Thu, 25 May 2023 12:11:38 +0100
"Russell King (Oracle)" [ref] wrote:

> 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" ?

Oh right... good catch, thanks !

> 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?
> 

You are correct, other fields are unused so I'll use a new struct for
the mii->priv field.

Thank you for reviewing,

Best regards,

Maxime
```