linux-kernel - Re: [net-next PATCH] net: phy: correctly check soft

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Message-ID: <ZVuUP797C4PLzJsP@lzaremba-mobl.ger.corp.intel.com>
Date:   Mon, 20 Nov 2023 18:15:43 +0100
From:   Larysa Zaremba <larysa.zaremba@...el.com>
To:     Christian Marangi <ansuelsmth@...il.com>
CC:     Andrew Lunn <andrew@...n.ch>,
        Heiner Kallweit <hkallweit1@...il.com>,
        Russell King <linux@...linux.org.uk>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        <netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [net-next PATCH] net: phy: correctly check soft_reset ret ONLY
 if defined for PHY

On Mon, Nov 20, 2023 at 02:15:40PM +0100, Christian Marangi wrote:
> soft_reset call for phy_init_hw had multiple revision across the years
> and the implementation goes back to 2014. Originally was a simple call
> to write the generic PHY reset BIT, it was then moved to a dedicated
> function. It was then added the option for PHY driver to define their
> own special way to reset the PHY. Till this change, checking for ret was
> correct as it was always filled by either the generic reset or the
> custom implementation. This changed tho with commit 6e2d85ec0559 ("net:
> phy: Stop with excessive soft reset"), as the generic reset call to PHY
> was dropped but the ret check was never made entirely optional and
> dependent whether soft_reset was defined for the PHY driver or not.
> 
> Luckly nothing was ever added before the soft_reset call so the ret
> check (in the case where a PHY didn't had soft_reset defined) although
> wrong, never caused problems as ret was init 0 at the start of
> phy_init_hw.
> 
> To prevent any kind of problem and to make the function cleaner and more
> robust, correctly move the ret check if the soft_reset section making it
> optional and needed only with the function defined.
> 
> Fixes: 6e2d85ec0559 ("net: phy: Stop with excessive soft reset")
> Signed-off-by: Christian Marangi <ansuelsmth@...il.com>
> ---
>  drivers/net/phy/phy_device.c | 9 ++++-----
>  1 file changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
> index 2ce74593d6e4..478126f6b5bc 100644
> --- a/drivers/net/phy/phy_device.c
> +++ b/drivers/net/phy/phy_device.c
> @@ -1235,14 +1235,13 @@ int phy_init_hw(struct phy_device *phydev)
>  
>  	if (phydev->drv->soft_reset) {
>  		ret = phydev->drv->soft_reset(phydev);
> +		if (ret < 0)
> +			return ret;
> +
>  		/* see comment in genphy_soft_reset for an explanation */
> -		if (!ret)
> -			phydev->suspended = 0;
> +		phydev->suspended = 0;

Are you sure 'suspended' should not be cleared, if soft_reset fails?

>  	}
>  
> -	if (ret < 0)
> -		return ret;
> -
>  	ret = phy_scan_fixups(phydev);
>  	if (ret < 0)
>  		return ret;
> -- 
> 2.40.1
> 
>