[PATCH] kvmtool: devices.c: Update parent when inserting into rbtree

From: James Morse <james.morse@arm.com>
To: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org
Cc: Will Deacon <will.deacon@arm.com>
Subject: [PATCH] kvmtool: devices.c: Update parent when inserting into rbtree
Date: Wed, 15 Jun 2016 11:59:08 +0100	[thread overview]
Message-ID: <1465988348-968-1-git-send-email-james.morse@arm.com> (raw)

When walking the devices rbtree to insert a node, we must keep track of the
parent node when we descend. If we skip this step, we always insert new
nodes with a NULL parent, bypassing __rb_insert()s rebalance code.

Things get worse when we come to walk the tree, as we can't move up a
level. This isn't a problem in practice, as all devices appear to be
inserted in-order, so our rbtree is actually a monochrome linked list.

Signed-off-by: James Morse <james.morse@arm.com>
---
 devices.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/devices.c b/devices.c
index b560a59..a7c666a 100644
--- a/devices.c
+++ b/devices.c
@@ -45,6 +45,7 @@ int device__register(struct device_header *dev)
 		int num = rb_entry(*node, struct device_header, node)->dev_num;
 		int result = dev->dev_num - num;
 
+		parent = *node;
 		if (result < 0)
 			node = &((*node)->rb_left);
 		else if (result > 0)
-- 
2.8.0.rc3
