Revert "drm/amdgpu: install stub fence into potential unused fence po…

…inters"

This reverts commit 04bd3a3 which is
commit 187916e upstream.

It is reported to cause lots of log spam, so it should be dropped for
now.

Reported-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/27d08b24-3581-4451-b8db-5df144784d6a@roeck-us.net
Reported-by: From: Chia-I Wu <olvaffe@gmail.com>
Link: https://lore.kernel.org/r/CAPaKu7RTgAMBLHbwtp4zgiBSDrTFtAj07k5qMzkuLQy2Zr+sZA@mail.gmail.com
Cc: Christian König <christian.koenig@amd.com>
Cc: Lang Yu <Lang.Yu@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

@@ -2155,7 +2155,6 @@ struct amdgpu_bo_va *amdgpu_vm_bo_add(struct amdgpu_device *adev,
 	amdgpu_vm_bo_base_init(&bo_va->base, vm, bo);
 
 	bo_va->ref_count = 1;
-	bo_va->last_pt_update = dma_fence_get_stub();
 	INIT_LIST_HEAD(&bo_va->valids);
 	INIT_LIST_HEAD(&bo_va->invalids);
 
@@ -2868,8 +2867,7 @@ int amdgpu_vm_init(struct amdgpu_device *adev, struct amdgpu_vm *vm,
 		vm->update_funcs = &amdgpu_vm_cpu_funcs;
 	else
 		vm->update_funcs = &amdgpu_vm_sdma_funcs;
-
-	vm->last_update = dma_fence_get_stub();
+	vm->last_update = NULL;
 	vm->last_unlocked = dma_fence_get_stub();
 
 	mutex_init(&vm->eviction_lock);
@@ -3044,7 +3042,7 @@ int amdgpu_vm_make_compute(struct amdgpu_device *adev, struct amdgpu_vm *vm,
 		vm->update_funcs = &amdgpu_vm_sdma_funcs;
 	}
 	dma_fence_put(vm->last_update);
-	vm->last_update = dma_fence_get_stub();
+	vm->last_update = NULL;
 	vm->is_compute_context = true;
 
 	if (vm->pasid) {