drm/amdgpu: use GEM references instead of TTMs v2

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

v2: fix typo in amdgpu_bo_unref pointed out by Vitaly,
initialize the GEM funcs for kernel allocations as well.

Signed-off-by: Christian König <[e-mail]>
Reviewed-by: Daniel Vetter <[e-mail]> (v1)
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c

···
 #include "amdgpu_hmm.h"
 #include "amdgpu_xgmi.h"
 
-static const struct drm_gem_object_funcs amdgpu_gem_object_funcs;
-
 static vm_fault_t amdgpu_gem_fault(struct vm_fault *vmf)
 {
 	struct ttm_buffer_object *bo = vmf->vma->vm_private_data;
···
 
 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);
 	}
 }
 
···
 
 	bo = &ubo->bo;
 	*obj = &bo->tbo.base;
-	(*obj)->funcs = &amdgpu_gem_object_funcs;
 
 	return 0;
 }
···
 	return drm_gem_ttm_mmap(obj, vma);
 }
 
-static const struct drm_gem_object_funcs amdgpu_gem_object_funcs = {
+const struct drm_gem_object_funcs amdgpu_gem_object_funcs = {
 	.free = amdgpu_gem_object_free,
 	.open = amdgpu_gem_object_open,
 	.close = amdgpu_gem_object_close,

drivers/gpu/drm/amd/amdgpu/amdgpu_gem.h

···
 #define AMDGPU_GEM_DOMAIN_MAX		0x3
 #define gem_to_amdgpu_bo(gobj) container_of((gobj), struct amdgpu_bo, tbo.base)
 
+extern const struct drm_gem_object_funcs amdgpu_gem_object_funcs;
+
 unsigned long amdgpu_gem_timeout(uint64_t timeout_ns);
 
 /*

drivers/gpu/drm/amd/amdgpu/amdgpu_object.c

···
 	if (bo == NULL)
 		return -ENOMEM;
 	drm_gem_private_object_init(adev_to_drm(adev), &bo->tbo.base, size);
+	bo->tbo.base.funcs = &amdgpu_gem_object_funcs;
 	bo->vm_bo = NULL;
 	bo->preferred_domains = bp->preferred_domain ? bp->preferred_domain :
 		bp->domain;
···
 	if (bo == NULL)
 		return NULL;
 
-	ttm_bo_get(&bo->tbo);
+	drm_gem_object_get(&bo->tbo.base);
 	return 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_put(&(*bo)->tbo.base);
 	*bo = NULL;
 }