From: Jesse Gross <jesse@nicira.com>
Date: Wed, 20 Mar 2013 23:14:58 +0000 (-0700)
Subject: datapath: Preallocate reply skb in ovs_vport_cmd_set().
X-Git-Tag: sliver-openvswitch-1.10.90-1~10^2~33
X-Git-Url: http://git.onelab.eu/?p=sliver-openvswitch.git;a=commitdiff_plain;h=c25ea53406a819bc2acff7b50e804c21f307bdec

datapath: Preallocate reply skb in ovs_vport_cmd_set().

Allocation of the Netlink notification skb can potentially fail
after changing vport configuration.  In general, we try to avoid
this by undoing any change we made but that is difficult for existing
objects.  This avoids the problem by preallocating the buffer (which
is fixed size).

Signed-off-by: Jesse Gross <jesse@nicira.com>
Acked-by: Pravin B Shelar <pshelar@nicira.com>
---

diff --git a/datapath/datapath.c b/datapath/datapath.c
index b5eb23291..5964789de 100644
--- a/datapath/datapath.c
+++ b/datapath/datapath.c
@@ -1856,10 +1856,8 @@ struct sk_buff *ovs_vport_cmd_build_info(struct vport *vport, u32 portid,
 		return ERR_PTR(-ENOMEM);
 
 	retval = ovs_vport_cmd_fill_info(vport, skb, portid, seq, 0, cmd);
-	if (retval < 0) {
-		kfree_skb(skb);
-		return ERR_PTR(retval);
-	}
+	BUG_ON(retval < 0);
+
 	return skb;
 }
 
@@ -2005,10 +2003,16 @@ static int ovs_vport_cmd_set(struct sk_buff *skb, struct genl_info *info)
 	    nla_get_u32(a[OVS_VPORT_ATTR_TYPE]) != vport->ops->type)
 		err = -EINVAL;
 
+	reply = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!reply) {
+		err = -ENOMEM;
+		goto exit_unlock;
+	}
+
 	if (!err && a[OVS_VPORT_ATTR_OPTIONS])
 		err = ovs_vport_set_options(vport, a[OVS_VPORT_ATTR_OPTIONS]);
 	if (err)
-		goto exit_unlock;
+		goto exit_free;
 
 	if (a[OVS_VPORT_ATTR_STATS])
 		ovs_vport_set_stats(vport, nla_data(a[OVS_VPORT_ATTR_STATS]));
@@ -2016,17 +2020,18 @@ static int ovs_vport_cmd_set(struct sk_buff *skb, struct genl_info *info)
 	if (a[OVS_VPORT_ATTR_UPCALL_PID])
 		vport->upcall_portid = nla_get_u32(a[OVS_VPORT_ATTR_UPCALL_PID]);
 
-	reply = ovs_vport_cmd_build_info(vport, info->snd_portid,
-					 info->snd_seq, OVS_VPORT_CMD_NEW);
-	if (IS_ERR(reply)) {
-		netlink_set_err(GENL_SOCK(sock_net(skb->sk)), 0,
-				ovs_dp_vport_multicast_group.id, PTR_ERR(reply));
-		goto exit_unlock;
-	}
+	err = ovs_vport_cmd_fill_info(vport, reply, info->snd_portid,
+				      info->snd_seq, 0, OVS_VPORT_CMD_NEW);
+	BUG_ON(err < 0);
 
 	genl_notify(reply, genl_info_net(info), info->snd_portid,
 		    ovs_dp_vport_multicast_group.id, info->nlhdr, GFP_KERNEL);
 
+	rtnl_unlock();
+	return 0;
+
+exit_free:
+	kfree_skb(reply);
 exit_unlock:
 	rtnl_unlock();
 exit: