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

[Daniel Vetter]

On Wed, Feb 24, 2021 at 6:14 PM Noralf Trønnes <noralf at tronnes.org> wrote:
>
>
>
> 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?

drm-misc-next-fixes because we're in the merge window.
-Daniel

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



-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch