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

[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.

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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