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Date:   Tue, 03 Jan 2023 11:21:08 +0100
From:   Michael Walle <michael@walle.cc>
To:     "Russell King (Oracle)" <linux@armlinux.org.uk>
Cc:     Heiner Kallweit <hkallweit1@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
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        Shenwei Wang <shenwei.wang@nxp.com>,
        Clark Wang <xiaoning.wang@nxp.com>,
        NXP Linux Team <linux-imx@nxp.com>,
        Sean Wang <sean.wang@mediatek.com>,
        Landen Chao <Landen.Chao@mediatek.com>,
        DENG Qingfang <dqfext@gmail.com>,
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        linux-mediatek@lists.infradead.org, Andrew Lunn <andrew@lunn.ch>,
        Geert Uytterhoeven <geert+renesas@glider.be>
Subject: Re: [PATCH RFC net-next v2 03/12] net: mdio: mdiobus_register: update
 validation test
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References: <20221227-v6-2-rc1-c45-seperation-v2-0-ddb37710e5a7@walle.cc>
 <20221227-v6-2-rc1-c45-seperation-v2-3-ddb37710e5a7@walle.cc>
 <Y7P/45Owf2IezIpO@shell.armlinux.org.uk>
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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@omp.ru/