[Intel-gfx] [PATCH] drm/i915: Return -EPERM when i915_gem_mmap_ioctl handling prime objects

[Daniel Vetter]

On Tue, Aug 15, 2017 at 3:18 PM, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> Quoting Daniel Vetter (2017-08-15 11:49:51)
>> On Tue, Aug 15, 2017 at 10:42 AM, Tina Zhang <tina.zhang at intel.com> wrote:
>> > Prime objects have no backing filp to GEM mmap pages from. So, for Prime
>> > objects, such operation is not permitted.
>>
>> EPERM is when you don't have enough permissions, but it's possible
>> (e.g. a feature requiring root, or drm master). -EINVAL is if
>> something is invalid, and not even root can change that. So from a
>> consistency pov, EINVAL is the right error code here I think.
>
> Consistency is that we wanted the same error code for all objects where
> you did not have the ability to change the underlying storage.
>
> The question is that an access issue or a permission issue. But at the
> very least, mmap_ioctl is the odd one out. Which the changelog did not
> explain and being sent out of context does not help.

Which other ioctl give you an EPERM for something that doesn't even
work when you're root and/or drm master or whatever it is that gives
you permission? I thought we've been pretty consistent with that one
...
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch