drm/amdgpu: cleanup VM dw estimation a bit

No functional change.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -1806,14 +1806,13 @@ static int amdgpu_vm_bo_update_mapping(struct amdgpu_device *adev,
 	/*
 	 * reserve space for two commands every (1 << BLOCK_SIZE)
 	 *  entries or 2k dwords (whatever is smaller)
-         *
-         * The second command is for the shadow pagetables.
 	 */
-	if (vm->root.base.bo->shadow)
-		ncmds = ((nptes >> min(adev->vm_manager.block_size, 11u)) + 1) * 2;
-	else
 	ncmds = ((nptes >> min(adev->vm_manager.block_size, 11u)) + 1);
 
+	/* The second command is for the shadow pagetables. */
+	if (vm->root.base.bo->shadow)
+		ncmds *= 2;
+
 	/* padding, etc. */
 	ndw = 64;
 
@@ -1831,10 +1830,11 @@ static int amdgpu_vm_bo_update_mapping(struct amdgpu_device *adev,
 		ndw += ncmds * 10;
 
 		/* extra commands for begin/end fragments */
+		ncmds = 2 * adev->vm_manager.fragment_size;
 		if (vm->root.base.bo->shadow)
-		        ndw += 2 * 10 * adev->vm_manager.fragment_size * 2;
-		else
-		        ndw += 2 * 10 * adev->vm_manager.fragment_size;
+			ncmds *= 2;
+
+		ndw += 10 * ncmds;
 
 		params.func = amdgpu_vm_do_set_ptes;
 	}