drm/amdgpu: Fix double free of dmabuf

amdgpu_amdkfd_gpuvm_free_memory_of_gpu drop dmabuf reference increased in
amdgpu_gem_prime_export.
amdgpu_bo_destroy drop dmabuf reference increased in
amdgpu_gem_prime_import.

So remove this extra dma_buf_put to avoid double free.
Signed-off-by: xinhui pan <xinhui.pan@amd.com>
Tested-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -646,12 +646,6 @@ kfd_mem_attach_dmabuf(struct amdgpu_device *adev, struct kgd_mem *mem,
 	if (IS_ERR(gobj))
 		return PTR_ERR(gobj);
 
-	/* Import takes an extra reference on the dmabuf. Drop it now to
-	 * avoid leaking it. We only need the one reference in
-	 * kgd_mem->dmabuf.
-	 */
-	dma_buf_put(mem->dmabuf);
-
 	*bo = gem_to_amdgpu_bo(gobj);
 	(*bo)->flags |= AMDGPU_GEM_CREATE_PREEMPTIBLE;
 	(*bo)->parent = amdgpu_bo_ref(mem->bo);