linux-kernel - Re: [RFC 02/11] net: phy: Simplify MMD device list termination

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Date:   Sat, 23 May 2020 19:36:10 +0100
From:   Russell King - ARM Linux admin <linux@...linux.org.uk>
To:     Jeremy Linton <jeremy.linton@....com>
Cc:     netdev@...r.kernel.org, davem@...emloft.net, andrew@...n.ch,
        f.fainelli@...il.com, hkallweit1@...il.com,
        madalin.bucur@....nxp.com, calvin.johnson@....nxp.com,
        linux-kernel@...r.kernel.org
Subject: Re: [RFC 02/11] net: phy: Simplify MMD device list termination

On Fri, May 22, 2020 at 04:30:50PM -0500, Jeremy Linton wrote:
> Since we are already checking for *devs == 0 after
> the loop terminates, we can add a mostly F's check
> as well. With that change we can simplify the return/break
> sequence inside the loop.
> 
> Add a valid_phy_id() macro for this, since we will be using it
> in a couple other places.

I'm not sure you have the name of this correct, and your usage layer
in your patch series is correct.

> 
> Signed-off-by: Jeremy Linton <jeremy.linton@....com>
> ---
>  drivers/net/phy/phy_device.c | 15 +++++++--------
>  1 file changed, 7 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
> index 245899b58a7d..7746c07b97fe 100644
> --- a/drivers/net/phy/phy_device.c
> +++ b/drivers/net/phy/phy_device.c
> @@ -695,6 +695,11 @@ static int get_phy_c45_devs_in_pkg(struct mii_bus *bus, int addr, int dev_addr,
>  	return 0;
>  }
>  
> +static bool valid_phy_id(int val)
> +{
> +	return (val > 0 && ((val & 0x1fffffff) != 0x1fffffff));
> +}
> +
>  /**
>   * get_phy_c45_ids - reads the specified addr for its 802.3-c45 IDs.
>   * @bus: the target MII bus
> @@ -732,18 +737,12 @@ static int get_phy_c45_ids(struct mii_bus *bus, int addr, u32 *phy_id,
>  			phy_reg = get_phy_c45_devs_in_pkg(bus, addr, 0, devs);
>  			if (phy_reg < 0)
>  				return -EIO;
> -			/* no device there, let's get out of here */
> -			if ((*devs & 0x1fffffff) == 0x1fffffff) {
> -				*phy_id = 0xffffffff;
> -				return 0;
> -			} else {
> -				break;
> -			}
> +			break;
>  		}
>  	}
>  
>  	/* no reported devices */
> -	if (*devs == 0) {
> +	if (!valid_phy_id(*devs)) {

You are using this to validate the "devices in package" value, not the
PHY ID value.  So, IMHO this should be called "valid_devs_in_package()"
or similar.

>  		*phy_id = 0xffffffff;
>  		return 0;
>  	}
> -- 
> 2.26.2
> 
> 

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTC for 0.8m (est. 1762m) line in suburbia: sync at 13.1Mbps down 424kbps up