netdev - RE: [PATCH net-next] bridge: fix setlink/dellink notifications

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Date:	Wed, 14 Jan 2015 23:22:00 +0000
From:	"Arad, Ronen" <ronen.arad@...el.com>
To:	"roopa@...ulusnetworks.com" <roopa@...ulusnetworks.com>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	"shemminger@...tta.com" <shemminger@...tta.com>,
	"vyasevic@...hat.com" <vyasevic@...hat.com>,
	"john.fastabend@...il.com" <john.fastabend@...il.com>,
	"tgraf@...g.ch" <tgraf@...g.ch>,
	"jhs@...atatu.com" <jhs@...atatu.com>,
	"sfeldma@...il.com" <sfeldma@...il.com>,
	"jiri@...nulli.us" <jiri@...nulli.us>
CC:	"wkok@...ulusnetworks.com" <wkok@...ulusnetworks.com>
Subject: RE: [PATCH net-next] bridge: fix setlink/dellink notifications



>-----Original Message-----
>From: netdev-owner@...r.kernel.org [mailto:netdev-owner@...r.kernel.org] On
>Behalf Of roopa@...ulusnetworks.com
>Sent: Tuesday, January 13, 2015 10:49 PM
>To: netdev@...r.kernel.org; shemminger@...tta.com; vyasevic@...hat.com;
>john.fastabend@...il.com; tgraf@...g.ch; jhs@...atatu.com; sfeldma@...il.com;
>jiri@...nulli.us
>Cc: wkok@...ulusnetworks.com
>Subject: [PATCH net-next] bridge: fix setlink/dellink notifications
>
>From: Roopa Prabhu <roopa@...ulusnetworks.com>
>
[..]
>diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
>index d06107d..4ac79ff 100644
>--- a/net/core/rtnetlink.c
>+++ b/net/core/rtnetlink.c
>@@ -2876,13 +2876,6 @@ static int rtnl_bridge_notify(struct net_device *dev,
>u16 flags)

The 'flags' argument was only used for applying the same handling of
MASTER/SELF flags to notification as used for setlink/delink.
This patch eliminates the MASTER case and leaves only SELF notification.
It seems clearer to eliminate flags argument and rename the function to
something like rtnl_bridge_self_notify().
   
> 		goto errout;
> 	}
>
>-	if ((!flags || (flags & BRIDGE_FLAGS_MASTER)) &&
>-	    br_dev && br_dev->netdev_ops->ndo_bridge_getlink) {
>-		err = br_dev->netdev_ops->ndo_bridge_getlink(skb, 0, 0, dev, 0);
>-		if (err < 0)
>-			goto errout;
>-	}
>-
> 	if ((flags & BRIDGE_FLAGS_SELF) &&
> 	    dev->netdev_ops->ndo_bridge_getlink) {
> 		err = dev->netdev_ops->ndo_bridge_getlink(skb, 0, 0, dev, 0);
>@@ -2958,16 +2951,19 @@ static int rtnl_bridge_setlink(struct sk_buff *skb,
>struct nlmsghdr *nlh)
> 			err = -EOPNOTSUPP;
> 		else
> 			err = dev->netdev_ops->ndo_bridge_setlink(dev, nlh);
>-
>-		if (!err)
>+		if (!err) {
> 			flags &= ~BRIDGE_FLAGS_SELF;
>+
>+			/* Generate event to notify upper layer of bridge
>+			 * change
>+			 */
>+			if (!err)
>+				err = rtnl_bridge_notify(dev, oflags);
>+		}
> 	}
>
> 	if (have_flags)
> 		memcpy(nla_data(attr), &flags, sizeof(flags));

What is the purpose of the above two lines (not changed by the patch)?
They seem to copy over the flags with the successfully applied cases
(MASTER and/or SELF) flags cleared back into the incoming netlink message.
I could not figure any place where the modified flags attribute is used

>-	/* Generate event to notify upper layer of bridge change */
>-	if (!err)
>-		err = rtnl_bridge_notify(dev, oflags);
> out:
> 	return err;
> }
>@@ -3032,15 +3028,19 @@ static int rtnl_bridge_dellink(struct sk_buff *skb,
>struct nlmsghdr *nlh)
> 		else
> 			err = dev->netdev_ops->ndo_bridge_dellink(dev, nlh);
>
>-		if (!err)
>+		if (!err) {
> 			flags &= ~BRIDGE_FLAGS_SELF;
>+
>+			/* Generate event to notify upper layer of bridge
>+			 * change
>+			 */
>+			err = rtnl_bridge_notify(dev, oflags);
>+		}
>+
> 	}
>
> 	if (have_flags)
> 		memcpy(nla_data(attr), &flags, sizeof(flags));
>-	/* Generate event to notify upper layer of bridge change */
>-	if (!err)
>-		err = rtnl_bridge_notify(dev, oflags);
> out:
> 	return err;
> }
>--
>1.7.10.4
>
>--
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