drm/amdgpu: Use dma_buf from GEM object instance

Avoid dereferencing struct drm_gem_object.import_attach for the
imported dma-buf. The dma_buf field in the GEM object instance refers
to the same buffer. Prepares to make import_attach an implementation
detail of PRIME.

Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Author: tdz

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

@@ -514,7 +514,7 @@ bool amdgpu_dmabuf_is_xgmi_accessible(struct amdgpu_device *adev,
 		return false;
 
 	if (drm_gem_is_imported(obj)) {
-		struct dma_buf *dma_buf = obj->import_attach->dmabuf;
+		struct dma_buf *dma_buf = obj->dma_buf;
 
 		if (dma_buf->ops != &amdgpu_dmabuf_ops)
 			/* No XGMI with non AMD GPUs */

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

@@ -317,8 +317,7 @@ static int amdgpu_gem_object_open(struct drm_gem_object *obj,
 	 */
 	if (!vm->is_compute_context || !vm->process_info)
 		return 0;
-	if (!drm_gem_is_imported(obj) ||
-	    !dma_buf_is_dynamic(obj->import_attach->dmabuf))
+	if (!drm_gem_is_imported(obj) || !dma_buf_is_dynamic(obj->dma_buf))
 		return 0;
 	mutex_lock_nested(&vm->process_info->lock, 1);
 	if (!WARN_ON(!vm->process_info->eviction_fence)) {

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

@@ -1272,7 +1272,7 @@ int amdgpu_vm_bo_update(struct amdgpu_device *adev, struct amdgpu_bo_va *bo_va,
 		struct drm_gem_object *obj = &bo->tbo.base;
 
 		if (drm_gem_is_imported(obj) && bo_va->is_xgmi) {
-			struct dma_buf *dma_buf = obj->import_attach->dmabuf;
+			struct dma_buf *dma_buf = obj->dma_buf;
 			struct drm_gem_object *gobj = dma_buf->priv;
 			struct amdgpu_bo *abo = gem_to_amdgpu_bo(gobj);