Re: [PATCH 1/9] drm/amdgpu: use GEM references instead of TTMs

[Christian König]

Am 16.07.24 um 23:53 schrieb Matthew Brost:

On Tue, Jul 16, 2024 at 02:35:11PM +0200, Christian König wrote:

Instead of a TTM reference grab a GEM reference whenever necessary.

Signed-off-by: Christian König <christian.koe...@amd.com>
---
  drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c    | 8 ++++----
  drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 7 ++-----
  2 files changed, 6 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
index 67c234bcf89f..6be3d7cd1c51 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
@@ -87,11 +87,11 @@ static const struct vm_operations_struct amdgpu_gem_vm_ops 
= {

static void amdgpu_gem_object_free(struct drm_gem_object *gobj)

  {
-       struct amdgpu_bo *robj = gem_to_amdgpu_bo(gobj);
+       struct amdgpu_bo *aobj = gem_to_amdgpu_bo(gobj);

- if (robj) {

-               amdgpu_hmm_unregister(robj);
-               amdgpu_bo_unref(&robj);
+       if (aobj) {
+               amdgpu_hmm_unregister(aobj);
+               ttm_bo_put(&aobj->tbo);

So, this relates to my comment in patch number #9 about dropping the TTM
ref count. If TTM only uses the GEM ref count, could we convert this
ttm_bo_put to something like ttm_bo_fini here (also in Xe and any other
drivers with code like this)?

That's exactly what I was planning to do as a follow up.

Regards,
Christian.

I think that might be cleaner.

Matt

        }
  }

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c

index 8d8c39be6129..6c187e310034 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
@@ -853,7 +853,7 @@ struct amdgpu_bo *amdgpu_bo_ref(struct amdgpu_bo *bo)
        if (bo == NULL)
                return NULL;

- ttm_bo_get(&bo->tbo);

+       drm_gem_object_get(&bo->tbo.base);
        return bo;
  }

@@ -865,13 +865,10 @@ struct amdgpu_bo *amdgpu_bo_ref(struct amdgpu_bo *bo)

   */
  void amdgpu_bo_unref(struct amdgpu_bo **bo)
  {
-       struct ttm_buffer_object *tbo;
-
        if ((*bo) == NULL)
                return;

- tbo = &((*bo)->tbo);

-       ttm_bo_put(tbo);
+       drm_gem_object_get(&(*bo)->tbo.base);
        *bo = NULL;
  }

--

2.34.1