From: Jarek Poplawski <jarkao2@gmail.com>
Date: Tue, 6 Jan 2009 02:14:19 +0000 (-0800)
Subject: pkt_sched: cls_u32: Fix locking in u32_change()
X-Git-Tag: v2.6.29-rc1~502^2~6
X-Git-Url: http://ftp.safe.ca/?p=safe%2Fjmp%2Flinux-2.6;a=commitdiff_plain;h=6f57321422e0d359e83c978c2b03db77b967b7d5

pkt_sched: cls_u32: Fix locking in u32_change()

New nodes are inserted in u32_change() under rtnl_lock() with wmb(),
so without tcf_tree_lock() like in other classifiers (e.g. cls_fw).
This isn't enough without rmb() on the read side, but on the other
hand adding such barriers doesn't give any savings, so the lock is
added instead.

Reported-by: m0sia <m0sia@plotinka.ru>
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c
index 05d1780..07372f6 100644
--- a/net/sched/cls_u32.c
+++ b/net/sched/cls_u32.c
@@ -638,8 +638,9 @@ static int u32_change(struct tcf_proto *tp, unsigned long base, u32 handle,
 				break;
 
 		n->next = *ins;
-		wmb();
+		tcf_tree_lock(tp);
 		*ins = n;
+		tcf_tree_unlock(tp);
 
 		*arg = (unsigned long)n;
 		return 0;