linux-kernel - Re: [PATCH] net: phy: Move interrupt check from phy_check to phy

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Message-ID: <20180308164613.GA7108@artie.amer.corp.natinst.com>
Date:   Thu, 8 Mar 2018 10:46:14 -0600
From:   Brad Mouring <brad.mouring@...com>
To:     Andrew Lunn <andrew@...n.ch>
CC:     Florian Fainelli <f.fainelli@...il.com>, <netdev@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] net: phy: Move interrupt check from phy_check to
 phy_interrupt

On Thu, Mar 08, 2018 at 05:29:05PM +0100, Andrew Lunn wrote:
> On Wed, Mar 07, 2018 at 04:50:42PM -0600, Brad Mouring wrote:
> > If multiple phys share the same interrupt (e.g. a multi-phy chip),
> > the first device registered is the only one checked as phy_interrupt
> > will always return IRQ_HANDLED if the first phydev is not halted.
> > Move the interrupt check into phy_interrupt and, if it was not this
> > phydev, return IRQ_NONE to allow other devices on this irq a chance
> > to check if it was their interrupt.
> > 
> > Signed-off-by: Brad Mouring <brad.mouring@...com>
> > ---
> >  drivers/net/phy/phy.c | 16 ++++++----------
> >  1 file changed, 6 insertions(+), 10 deletions(-)
> > 
> > diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
> > index e3e29c2b028b..ff1aa815568f 100644
> > --- a/drivers/net/phy/phy.c
> > +++ b/drivers/net/phy/phy.c
> > @@ -632,6 +632,12 @@ static irqreturn_t phy_interrupt(int irq, void *phy_dat)
> >  	if (PHY_HALTED == phydev->state)
> >  		return IRQ_NONE;		/* It can't be ours.  */
> >  
> > +	if (phy_interrupt_is_valid(phydev)) {
> 
> Hi Brad
> 
> Is this check needed? Can phy_interrupt() be called for a PHY which
> does not have an interrupt?

Ah, fair point (and I guess a result of copy-pasting without
thinking), to address this and the next point...

> > +		if (phydev->drv->did_interrupt &&
> > +			!phydev->drv->did_interrupt(phydev))
> > +			return IRQ_NONE;
> > +	}
> > +
> >  	phy_change(phydev);
> >  
> >  	return IRQ_HANDLED;
> > @@ -725,16 +731,6 @@ EXPORT_SYMBOL(phy_stop_interrupts);
> >   */
> >  void phy_change(struct phy_device *phydev)
> >  {
> > -	if (phy_interrupt_is_valid(phydev)) {
> > -		if (phydev->drv->did_interrupt &&
> > -		    !phydev->drv->did_interrupt(phydev))
> > -			return;
> > -
> > -		if (phydev->state == PHY_HALTED)
> > -			if (phy_disable_interrupts(phydev))
> > -				goto phy_err;
> > -	}
> > -
> 
> phy_change() can also be called via phy_mac_interrupt(). I wonder if
> this change is going to break anything? Did you think about that?

Thanks for pointing this out. I'll post a v2 that (hopefully) address
both of these valid points.

Thanks,
Brad