Messages in this thread | | | From | Thomas Zimmermann <> | Subject | Re: [PATCH] drm/irq: Add irq as false detection | Date | Mon, 2 Nov 2020 13:09:39 +0100 |
| |
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@hisilicon.com> > --- > 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.
Best regards Thomas
> irq_enabled = dev->irq_enabled; > dev->irq_enabled = false; > >
-- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Maxfeldstr. 5, 90409 Nürnberg, Germany (HRB 36809, AG Nürnberg) Geschäftsführer: Felix Imendörffer [unhandled content-type:application/pgp-keys][unhandled content-type:application/pgp-signature] | |