Re: [PATCH] drm/irq: Add irq as false detection

[tiantao (H)]

在 2020/11/2 20:09, Thomas Zimmermann 写道:
> Hi
>
> Am 02.11.20 um 12:19 schrieb Tian Tao:
> > Add the detection of false for irq, so that the EINVAL is not
> > returned when dev->irq_enabled is false.
> >
> > Signed-off-by: Tian Tao <tiantao6@xxxxxxxxxxxxx>
> > ---
> >   drivers/gpu/drm/drm_irq.c | 3 +++
> >   1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
> > index 09d6e9e..7537a3d 100644
> > --- a/drivers/gpu/drm/drm_irq.c
> > +++ b/drivers/gpu/drm/drm_irq.c
> > @@ -172,6 +172,9 @@ int drm_irq_uninstall(struct drm_device *dev)
> >   	bool irq_enabled;
> >   	int i;
> >   
> > +	if (!dev->irq_enabled || !dev)
> > +		return 0;
> > +
>
> Dereferencing a pointer before NULL-checking it, is Yoda programming. :)
> I'd just drop the test for !dev and assume that dev is always valid.
>
> I suggest to change the int return value to void and return nothing.
>
> Re-reading the actual implementation of this function, this location
> might be too early. Further below there already is a test for
> irq_enabled. Put a drm_WARN_ON around it and it should be fine. This way
> the vblank handlers will be disabled and erroneous callers will see a
> warning in the kernel's log.
thank you，I will send a new patch to fix that.
> Best regards
> Thomas
>
> >   	irq_enabled = dev->irq_enabled;
> >   	dev->irq_enabled = false;
> >