[patch 39/86] lib/rbtree: get successor's color directly

Andrew Morton
2019-12-05T00:51:53Z

From: Wei Yang <richardw.yang@linux.intel.com>
Subject: lib/rbtree: get successor's color directly

After move parent assignment out, we can check the color directly.

Link: http://lkml.kernel.org/r/20191028021442.5450-2-richardw.yang@linux.intel.com
Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

include/linux/rbtree_augmented.h | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

--- a/include/linux/rbtree_augmented.h~lib-rbtree-get-successors-color-directly
+++ a/include/linux/rbtree_augmented.h
@@ -286,8 +286,7 @@ __rb_erase_augmented(struct rb_node *nod
rb_set_parent_color(child2, parent, RB_BLACK);
rebalance = NULL;
} else {
- unsigned long pc2 = successor->__rb_parent_color;
- rebalance = __rb_is_black(pc2) ? parent : NULL;
+ rebalance = rb_is_black(successor) ? parent : NULL;
}
successor->__rb_parent_color = pc;
tmp = successor;
_