[PATCH v3 4/4] mm/vmap: move BUG_ON() check to the unlink_va()

[Uladzislau Rezki (Sony)]

Move the BUG_ON()/RB_EMPTY_NODE() check under unlink_va()
function, it means if an empty node gets freed it is a BUG
thus is considered as faulty behaviour.

Signed-off-by: Uladzislau Rezki (Sony) <ure...@gmail.com>
---
 mm/vmalloc.c | 24 +++++++++---------------
 1 file changed, 9 insertions(+), 15 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 371aba9a4bf1..340959b81228 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -533,20 +533,16 @@ link_va(struct vmap_area *va, struct rb_root *root,
 static __always_inline void
 unlink_va(struct vmap_area *va, struct rb_root *root)
 {
-       /*
-        * During merging a VA node can be empty, therefore
-        * not linked with the tree nor list. Just check it.
-        */
-       if (!RB_EMPTY_NODE(&va->rb_node)) {
-               if (root == &free_vmap_area_root)
-                       rb_erase_augmented(&va->rb_node,
-                               root, &free_vmap_area_rb_augment_cb);
-               else
-                       rb_erase(&va->rb_node, root);
+       BUG_ON(RB_EMPTY_NODE(&va->rb_node));
 
-               list_del(&va->list);
-               RB_CLEAR_NODE(&va->rb_node);
-       }
+       if (root == &free_vmap_area_root)
+               rb_erase_augmented(&va->rb_node,
+                       root, &free_vmap_area_rb_augment_cb);
+       else
+               rb_erase(&va->rb_node, root);
+
+       list_del(&va->list);
+       RB_CLEAR_NODE(&va->rb_node);
 }
 
 #if DEBUG_AUGMENT_PROPAGATE_CHECK
@@ -1187,8 +1183,6 @@ EXPORT_SYMBOL_GPL(unregister_vmap_purge_notifier);
 
 static void __free_vmap_area(struct vmap_area *va)
 {
-       BUG_ON(RB_EMPTY_NODE(&va->rb_node));
-
        /*
         * Remove from the busy tree/list.
         */
-- 
2.11.0