[PATCH v4 1/7] drm/ttm: Don't override vm_ops callbacks, if set

[Thomas Zimmermann]

Drivers may want to set their own callbacks for a VM area. Only set
TTM's callbacks if the vm_ops field is clear.

Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
---
 drivers/gpu/drm/ttm/ttm_bo_vm.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c
index 7ff9fd551357..ff07dbc91c03 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_vm.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c
@@ -586,7 +586,12 @@ static struct ttm_buffer_object *ttm_bo_vm_lookup(struct ttm_device *bdev,
 
 static void ttm_bo_mmap_vma_setup(struct ttm_buffer_object *bo, struct vm_area_struct *vma)
 {
-	vma->vm_ops = &ttm_bo_vm_ops;
+	/*
+	 * Drivers may want to override the vm_ops field. Otherwise we
+	 * use TTM's default callbacks.
+	 */
+	if (!vma->vm_ops)
+		vma->vm_ops = &ttm_bo_vm_ops;
 
 	/*
 	 * Note: We're transferring the bo reference to
-- 
2.31.1