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Date:   Sat, 5 Jun 2021 01:02:21 +0200
From:   Andrew Lunn <andrew@lunn.ch>
To:     Heiner Kallweit <hkallweit1@gmail.com>
Cc:     dingsenjie@163.com, richardcochran@gmail.com, davem@davemloft.net,
        kuba@kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, dingsenjie <dingsenjie@yulong.com>
Subject: Re: [PATCH] net: phy: Simplify the return expression of
 dp83640_ack_interrupt
Message-ID: <YLqw/Z22iMATS1IF@lunn.ch>
References: <20210604032224.136268-1-dingsenjie@163.com>
 <91609670-c3a2-2281-514e-01dfe7907f11@gmail.com>
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On Fri, Jun 04, 2021 at 09:49:17AM +0200, Heiner Kallweit wrote:
> On 04.06.2021 05:22, dingsenjie@163.com wrote:
> > From: dingsenjie <dingsenjie@yulong.com>
> > 
> > Simplify the return expression.
> > 
> > Signed-off-by: dingsenjie <dingsenjie@yulong.com>
> > ---
> >  drivers/net/phy/dp83640.c | 7 +------
> >  1 file changed, 1 insertion(+), 6 deletions(-)
> > 
> > diff --git a/drivers/net/phy/dp83640.c b/drivers/net/phy/dp83640.c
> > index 0d79f68..bcd14ec 100644
> > --- a/drivers/net/phy/dp83640.c
> > +++ b/drivers/net/phy/dp83640.c
> > @@ -1141,12 +1141,7 @@ static int dp83640_config_init(struct phy_device *phydev)
> >  
> >  static int dp83640_ack_interrupt(struct phy_device *phydev)
> >  {
> > -	int err = phy_read(phydev, MII_DP83640_MISR);
> > -
> > -	if (err < 0)
> > -		return err;
> > -
> > -	return 0;
> > +	return phy_read(phydev, MII_DP83640_MISR);
> >  }
> >  
> >  static int dp83640_config_intr(struct phy_device *phydev)
> > 
> This would be a functional change. You'd return a positive value
> instead of 0.

And looking a bit further down in the code:

static int dp83640_ack_interrupt(struct phy_device *phydev)
{
        int err = phy_read(phydev, MII_DP83640_MISR);

        if (err < 0)
                return err;

        return 0;
}

static int dp83640_config_intr(struct phy_device *phydev)
{
        int micr;
        int misr;
        int err;

        if (phydev->interrupts == PHY_INTERRUPT_ENABLED) {
                err = dp83640_ack_interrupt(phydev);
                if (err)
                        return err;

So a positive value is going to break the driver.

NACK

	Andrew