netdev - [PATCH net 5/6] rtnetlink: check DO_SETLINK_NOTIFY correctly in do

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Date:   Sun, 15 Oct 2017 18:13:45 +0800
From:   Xin Long <lucien.xin@...il.com>
To:     network dev <netdev@...r.kernel.org>
Cc:     davem@...emloft.net, David Ahern <dsahern@...il.com>,
        hannes@...essinduktion.org
Subject: [PATCH net 5/6] rtnetlink: check DO_SETLINK_NOTIFY correctly in do_setlink

The check 'status & DO_SETLINK_NOTIFY' in do_setlink doesn't really
work after status & DO_SETLINK_MODIFIED, as:

  DO_SETLINK_MODIFIED 0x1
  DO_SETLINK_NOTIFY 0x3

Considering that notifications are suppposed to be sent only when
status have the flag DO_SETLINK_NOTIFY, the right check would be:

  (status & DO_SETLINK_NOTIFY) == DO_SETLINK_NOTIFY

This would avoid lots of duplicated notifications when setting some
properties of a link.

Fixes: ba9989069f4e ("rtnl/do_setlink(): notify when a netdev is modified")
Signed-off-by: Xin Long <lucien.xin@...il.com>
---
 net/core/rtnetlink.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index ab98c1c..3e98fb5 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -2248,7 +2248,7 @@ static int do_setlink(const struct sk_buff *skb,
 
 errout:
 	if (status & DO_SETLINK_MODIFIED) {
-		if (status & DO_SETLINK_NOTIFY)
+		if ((status & DO_SETLINK_NOTIFY) == DO_SETLINK_NOTIFY)
 			netdev_state_change(dev);
 
 		if (err < 0)
-- 
2.1.0