Re: [PATCH RFC net-next v2 03/12] net: mdio: mdiobus_register: update validation test

[Michael Walle]

Hi Russell,

Am 2023-01-03 11:13, schrieb Russell King (Oracle):
> On Wed, Dec 28, 2022 at 12:07:19AM +0100, Michael Walle wrote:
> > +	if (!bus || !bus->name)
> > +		return -EINVAL;
> > +
> > +	/* An access method always needs both read and write operations */
> > +	if ((bus->read && !bus->write) ||
> > +	    (!bus->read && bus->write) ||
> > +	    (bus->read_c45 && !bus->write_c45) ||
> > +	    (!bus->read_c45 && bus->write_c45))
>
> I wonder whether the following would be even more readable:
>
> 	if (!bus->read != !bus->write || !bus->read_c45 != !bus->write_c45)

That's what Andrew had originally. But there was a comment from Sergey 
[1]
which I agree with. I had a hard time wrapping my head around that, so I
just listed all the possible bad cases.

I don't have a strong opinion, though.

> which essentially asserts that the boolean of !method for the read and
> write methods must match.

Maybe with that as a comment?

-michael

[1] 
https://lore.kernel.org/netdev/ae79823f-3697-feee-32e6-645c6f4b4e93@xxxxxx/