[PATCH v2] drm/amdgpu: fix the wrong logic checking when secure buffer is created (v2)

[Huang Rui]

On Tue, Feb 18, 2020 at 05:15:33PM +0800, Koenig, Christian wrote:
> Am 18.02.20 um 09:55 schrieb Huang Rui:
> > On Tue, Feb 18, 2020 at 04:50:01PM +0800, Koenig, Christian wrote:
> >> Am 18.02.20 um 09:30 schrieb Huang Rui:
> >>> While the current amdgpu doesn't support TMZ, it will return the error if user
> >>> mode would like to allocate secure buffer.
> >>>
> >>> Fixes: 17d907c drm/amdgpu: implement TMZ accessor (v3)
> >>>
> >>> v2: we didn't need this checking anymore.
> >> You misunderstood me.
> >>
> > ok...
> >
> >>> Signed-off-by: Huang Rui <ray.huang at amd.com>
> >>> ---
> >>>    drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c | 5 -----
> >>>    1 file changed, 5 deletions(-)
> >>>
> >>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
> >>> index b51a060..5cbc63a 100644
> >>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
> >>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
> >>> @@ -235,11 +235,6 @@ int amdgpu_gem_create_ioctl(struct drm_device *dev, void *data,
> >>>    	if (args->in.domains & ~AMDGPU_GEM_DOMAIN_MASK)
> >>>    		return -EINVAL;
> >>>    
> >>> -	if (amdgpu_is_tmz(adev) && (flags & AMDGPU_GEM_CREATE_ENCRYPTED)) {
> >>> -		DRM_ERROR("Cannot allocate secure buffer since TMZ is disabled\n");
> >> Only the error message should be removed, but we still need to test the
> >> flag.
> >>
> >> E.g. in general we should never log that userspace sends invalid parameters.
> >>
> > Why? It probably can help userspace to understand what wrong input it is.
> 
> That's correct, but it also allows userspace to spam the logs with those 
> messages.
> 
> While the kernel tools are rather clever and filter out repeated 
> messages this is still considered a bad idea because it might hide more 
> serious error messages.
> 
> What we could do is either make this debug severity or use something 
> DRM_NOTE_ONCE() to print it only once.

I see, make sense. There is no DRM_ERROR_ONCE() and I think this case is
not very hard to check. So let's remove the error message only as you
suggested.

Thanks,
Ray