Re: [PATCH net v2] net: dsa: mv88e6xxx: lock mutex when freeing IRQs

[Andrew Lunn <andrew@lunn.ch>]

On Wed, Sep 27, 2017 at 09:06:01AM +0000, David Laight wrote:
> From: Vivien Didelot
> > Sent: 26 September 2017 19:57
> > mv88e6xxx_g2_irq_free locks the registers mutex, but not
> > mv88e6xxx_g1_irq_free, which results in a stack trace from
> > assert_reg_lock when unloading the mv88e6xxx module. Fix this.
> > 
> > Fixes: 3460a5770ce9 ("net: dsa: mv88e6xxx: Mask g1 interrupts and free interrupt")
> > Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
> > ---
> >  drivers/net/dsa/mv88e6xxx/chip.c | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
> > index c6678aa9b4ef..e7ff7483d2fb 100644
> > --- a/drivers/net/dsa/mv88e6xxx/chip.c
> > +++ b/drivers/net/dsa/mv88e6xxx/chip.c
> > @@ -3947,7 +3947,9 @@ static void mv88e6xxx_remove(struct mdio_device *mdiodev)
> >  	if (chip->irq > 0) {
> >  		if (chip->info->g2_irqs > 0)
> >  			mv88e6xxx_g2_irq_free(chip);
> > +		mutex_lock(&chip->reg_lock);
> >  		mv88e6xxx_g1_irq_free(chip);
> > +		mutex_unlock(&chip->reg_lock);
> 
> Isn't the irq_free code likely to have to sleep waiting for any
> ISR to complete??

Hi David

Possibly. But this is a mutex, not a spinlock. So sleeping is O.K.
Or am i missing something?

	  Andrew