[PATCH 1/2] drm/amdgpu: Generalize KFD dmabuf import

[Felix Kuehling <Felix.Kuehling@xxxxxxx>]

Use proper amdgpu_gem_prime_import function to handle all kinds of
imports. Remember the dmabuf reference to enable proper multi-GPU
attachment to multiple VMs without erroneously re-exporting the
underlying BO multiple times.

Signed-off-by: Felix Kuehling <Felix.Kuehling@xxxxxxx>
---
 .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c  | 45 ++++++++++++-------
 1 file changed, 28 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
index 90b985436878..d53d19b9d6dc 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
@@ -2000,30 +2000,34 @@ int amdgpu_amdkfd_gpuvm_import_dmabuf(struct amdgpu_device *adev,
 	struct amdgpu_bo *bo;
 	int ret;
 
-	if (dma_buf->ops != &amdgpu_dmabuf_ops)
-		/* Can't handle non-graphics buffers */
-		return -EINVAL;
-
-	obj = dma_buf->priv;
-	if (drm_to_adev(obj->dev) != adev)
-		/* Can't handle buffers from other devices */
-		return -EINVAL;
+	obj = amdgpu_gem_prime_import(adev_to_drm(adev), dma_buf);
+	if (IS_ERR(obj))
+		return PTR_ERR(obj);
+	if (obj->import_attach) {
+		/* Import takes an extra reference if it creates a dynamic
+		 * dmabuf attachment. Release that reference to avoid
+		 * leaking it. FIXME: I think this is a bug.
+		 */
+		dma_buf_put(dma_buf);
+	}
 
 	bo = gem_to_amdgpu_bo(obj);
 	if (!(bo->preferred_domains & (AMDGPU_GEM_DOMAIN_VRAM |
-				    AMDGPU_GEM_DOMAIN_GTT)))
+				    AMDGPU_GEM_DOMAIN_GTT))) {
 		/* Only VRAM and GTT BOs are supported */
-		return -EINVAL;
+		ret = -EINVAL;
+		goto err_put_obj;
+	}
 
 	*mem = kzalloc(sizeof(struct kgd_mem), GFP_KERNEL);
-	if (!*mem)
-		return -ENOMEM;
+	if (!*mem) {
+		ret = -ENOMEM;
+		goto err_put_obj;
+	}
 
 	ret = drm_vma_node_allow(&obj->vma_node, drm_priv);
-	if (ret) {
-		kfree(mem);
-		return ret;
-	}
+	if (ret)
+		goto err_free_mem;
 
 	if (size)
 		*size = amdgpu_bo_size(bo);
@@ -2040,7 +2044,8 @@ int amdgpu_amdkfd_gpuvm_import_dmabuf(struct amdgpu_device *adev,
 		| KFD_IOC_ALLOC_MEM_FLAGS_WRITABLE
 		| KFD_IOC_ALLOC_MEM_FLAGS_EXECUTABLE;
 
-	drm_gem_object_get(&bo->tbo.base);
+	get_dma_buf(dma_buf);
+	(*mem)->dmabuf = dma_buf;
 	(*mem)->bo = bo;
 	(*mem)->va = va;
 	(*mem)->domain = (bo->preferred_domains & AMDGPU_GEM_DOMAIN_VRAM) ?
@@ -2052,6 +2057,12 @@ int amdgpu_amdkfd_gpuvm_import_dmabuf(struct amdgpu_device *adev,
 	(*mem)->is_imported = true;
 
 	return 0;
+
+err_free_mem:
+	kfree(mem);
+err_put_obj:
+	drm_gem_object_put(obj);
+	return ret;
 }
 
 /* Evict a userptr BO by stopping the queues if necessary
-- 
2.32.0