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

[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?

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);
>>   }
>>     /*
>>
>