[PATCH] drm/shmem-helpers: vunmap: Don't put pages for dma-buf

[Thomas Zimmermann]

Am 25.02.21 um 10:25 schrieb Noralf Trønnes:
> 
> 
> Den 25.02.2021 09.12, skrev Thomas Zimmermann:
>> Hi
>>
>> Am 24.02.21 um 18:14 schrieb Noralf Trønnes:
>>>
>>>
>>> Den 19.02.2021 14.54, skrev Thomas Zimmermann:
>>>> Hi
>>>>
>>>> Am 19.02.21 um 13:22 schrieb Noralf Trønnes:
>>>>> dma-buf importing was reworked in commit 7d2cd72a9aa3
>>>>> ("drm/shmem-helpers: Simplify dma-buf importing"). Before that commit
>>>>> drm_gem_shmem_prime_import_sg_table() did set ->pages_use_count=1 and
>>>>> drm_gem_shmem_vunmap_locked() could call drm_gem_shmem_put_pages()
>>>>> unconditionally. Now without the use count set, put pages is called
>>>>> also
>>>>> on dma-bufs. Fix this by only putting pages if it's not imported.
>>>>>
>>>>> Fixes: 7d2cd72a9aa3 ("drm/shmem-helpers: Simplify dma-buf importing")
>>>>> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
>>>>> Cc: Thomas Zimmermann <tzimmermann at suse.de>
>>>>> Signed-off-by: Noralf Trønnes <noralf at tronnes.org>
>>>>
>>>> Just when I saw the error. Nice. :)
>>>>
>>>> Acked-by: Thomas Zimmermann <tzimmermann at suse.de>
>>>> Tested-by: Thomas Zimmermann <tzimmermann at suse.de>
>>>>
>>>
>>> Should I apply this to drm-misc-fixes?
>>
>> I think so. Ping me if you want me to add it.
>>
> 
> I'd appreciate if you could do it. I haven't applied a patch in almost a
> year now and need to dig out my notes on how I do it. -fixes stuff is
> for me a "hold my breath and hope I don't screw up anything" exercise.
> Stressful :/

Applied now to drm-misc-next. If it breaks, I'll also take the blame. :) 
I took the liberty of moving your S-o-b line to the top of the tag. IIRC 
this is the preferred style. Thanks again for the fix.

Best regards
Thomas

> 
> One day in the future I hope there's a green button I can push that
> says: Merge patch to -fixes and make sure everything is OK. That would
> be nice :)
> 
> Thanks,
> Noralf.
> 
>> Best regards
>> Thomas
>>
>>>
>>> Noralf.
>>>
>>>> For testing the GUD driver, you may also want to keep an eye at [1]
>>>>
>>>> Best regards
>>>> Thomas
>>>>
>>>> [1]
>>>> https://lore.kernel.org/dri-devel/02a45c11-fc73-1e5a-3839-30b080950af8@amd.com/T/#t
>>>>
>>>>
>>>>
>>>>> ---
>>>>>     drivers/gpu/drm/drm_gem_shmem_helper.c | 7 ++++---
>>>>>     1 file changed, 4 insertions(+), 3 deletions(-)
>>>>>
>>>>> diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c
>>>>> b/drivers/gpu/drm/drm_gem_shmem_helper.c
>>>>> index 9825c378dfa6..c8a6547a1757 100644
>>>>> --- a/drivers/gpu/drm/drm_gem_shmem_helper.c
>>>>> +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
>>>>> @@ -357,13 +357,14 @@ static void drm_gem_shmem_vunmap_locked(struct
>>>>> drm_gem_shmem_object *shmem,
>>>>>         if (--shmem->vmap_use_count > 0)
>>>>>             return;
>>>>>     -    if (obj->import_attach)
>>>>> +    if (obj->import_attach) {
>>>>>             dma_buf_vunmap(obj->import_attach->dmabuf, map);
>>>>> -    else
>>>>> +    } else {
>>>>>             vunmap(shmem->vaddr);
>>>>> +        drm_gem_shmem_put_pages(shmem);
>>>>> +    }
>>>>>           shmem->vaddr = NULL;
>>>>> -    drm_gem_shmem_put_pages(shmem);
>>>>>     }
>>>>>       /*
>>>>>
>>>>
>>

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

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