Re: [PATCH 4/4] drm/tegra: Use u64_to_user_ptr helper

[Mikko Perttunen]

On 08/19/2017 01:05 AM, Dmitry Osipenko wrote:
> On 18.08.2017 19:15, Mikko Perttunen wrote:
> > Use the u64_to_user_ptr helper macro to cast IOCTL argument u64 values
> > to user pointers instead of writing out the cast manually.
> >
> > Signed-off-by: Mikko Perttunen <mperttunen@xxxxxxxxxx>
> > ---
> >   drivers/gpu/drm/tegra/drm.c | 9 ++++-----
> >   1 file changed, 4 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c
> > index e3331a2bc082..78c98736b0a5 100644
> > --- a/drivers/gpu/drm/tegra/drm.c
> > +++ b/drivers/gpu/drm/tegra/drm.c
> > @@ -389,11 +389,10 @@ int tegra_drm_submit(struct tegra_drm_context *context,
> >   	unsigned int num_relocs = args->num_relocs;
> >   	unsigned int num_waitchks = args->num_waitchks;
> >   	struct drm_tegra_cmdbuf __user *cmdbufs =
> > -		(void __user *)(uintptr_t)args->cmdbufs;
> > -	struct drm_tegra_reloc __user *relocs =
> > -		(void __user *)(uintptr_t)args->relocs;
> > +		u64_to_user_ptr(args->cmdbufs);
> > +	struct drm_tegra_reloc __user *relocs = u64_to_user_ptr(args->relocs);
> >   	struct drm_tegra_waitchk __user *waitchks =
> > -		(void __user *)(uintptr_t)args->waitchks;
> > +		u64_to_user_ptr(args->waitchks);
>
> What about to factor out 'u64_to_user_ptr()' assignments to reduce messiness a
> tad? Like this:
>
> 	struct drm_tegra_waitchk __user *waitchks;
> 	struct drm_tegra_cmdbuf __user *cmdbufs;
> 	struct drm_tegra_reloc __user *relocs;
> ...
> 	waitchks = u64_to_user_ptr(args->waitchks);
> 	cmdbufs = u64_to_user_ptr(args->cmdbufs);
> 	relocs = u64_to_user_ptr(args->relocs);
>
>
> >   	struct drm_tegra_syncpt syncpt;
> >   	struct host1x *host1x = dev_get_drvdata(drm->dev->parent);
> >   	struct host1x_syncpt *sp;
> > @@ -520,7 +519,7 @@ int tegra_drm_submit(struct tegra_drm_context *context,
> >   		}
> >   	}
> >   
> > -	if (copy_from_user(&syncpt, (void __user *)(uintptr_t)args->syncpts,
> > +	if (copy_from_user(&syncpt, u64_to_user_ptr(args->syncpts),
>
> What about to define and use 'struct drm_tegra_reloc __user *syncpts' for
> consistency with other '__user' definitions?
>
> >   			   sizeof(syncpt))) {
> >   		err = -EFAULT;
> >   		goto fail;

Yeah, these are good ideas. I'll post a v2 at some point with these 
changes. Thanks!

Mikko