[PATCH] drm: Return error codes from struct drm_driver.gem_create_object

[Thomas Zimmermann]

Hi

Am 06.12.21 um 15:40 schrieb Dan Carpenter:
> On Mon, Dec 06, 2021 at 12:16:24PM +0100, Thomas Zimmermann wrote:
>> Hi
>>
>> Am 06.12.21 um 11:42 schrieb Dan Carpenter:
>>> On Tue, Nov 30, 2021 at 10:52:55AM +0100, Thomas Zimmermann wrote:
>>>> GEM helper libraries use struct drm_driver.gem_create_object to let
>>>> drivers override GEM object allocation. On failure, the call returns
>>>> NULL.
>>>>
>>>> Change the semantics to make the calls return a pointer-encoded error.
>>>> This aligns the callback with its callers. Fixes the ingenic driver,
>>>> which already returns an error pointer.
>>>>
>>>> Also update the callers to handle the involved types more strictly.
>>>>
>>>> Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
>>>> ---
>>>> There is an alternative patch at [1] that updates the value returned
>>>> by ingenics' gem_create_object to NULL. Fixing the interface to return
>>>> an errno code is more consistent with the rest of the GEM functions.
>>>>
>>>> [1] https://lore.kernel.org/dri-devel/20211118111522.GD1147@kili/
>>>
>>> My fix was already applied and backported to -stable etc...  Your
>>> patch is not developed against a current tree so you broke it.
>>
>> Do you have a specific link? I just checked the stable tree at [1] and there
>> no trace of your patch.
> 
> It's in 5.15.6 and probably all the other supported -stable trees.
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/drivers/gpu/drm/vc4/vc4_bo.c?h=v5.15.6#n387

I'm not sure that I understand the problem.

The URL points to vc4, but my link was to your patch for ingenic. vc4 is 
being updated here as well to ERR_PTR. The ingenic patch never made it 
into any tree. It actually was the reason to fix the interface.

When the current patch makes it through the trees, it should fix all the 
affected drivers.

Best regards
Thomas

> 
>>
>> Patches for DRM should go through through DRM trees; drm-misc-fixes in this
>> case. Exceptions should at least be announce on dri-devel. Neither is the
>> case here.
> 
> Yeah.  That's a good question.  I don't know, because I just work
> against linux-next...
> 
> regards,
> dan carpenter
> 
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev
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