[PATCH v1 net-next 2/8] rtnetlink: Factorise rtnl_link_get_net_tb().

[Kuniyuki Iwashima <kuniyu@amazon.com>]

In ops->newlink(), veth, vxcan, and netkit call rtnl_link_get_net() with
a net pointer, which is the first argument of ->newlink().

rtnl_link_get_net() could return another netns based on IFLA_NET_NS_PID
and IFLA_NET_NS_FD in the peer device's attributes.

We want to get it and fill rtnl_nets->nets[] in advance.

Let's factorise the peer netns part from rtnl_link_get_net().

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
 include/net/rtnetlink.h |  1 +
 net/core/rtnetlink.c    | 17 ++++++++++++++---
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/include/net/rtnetlink.h b/include/net/rtnetlink.h
index 814364367dd7..b9ed44b2d056 100644
--- a/include/net/rtnetlink.h
+++ b/include/net/rtnetlink.h
@@ -221,6 +221,7 @@ struct rtnl_af_ops {
 int rtnl_af_register(struct rtnl_af_ops *ops);
 void rtnl_af_unregister(struct rtnl_af_ops *ops);
 
+struct net *rtnl_link_get_net_tb(struct nlattr *tb[]);
 struct net *rtnl_link_get_net(struct net *src_net, struct nlattr *tb[]);
 struct net_device *rtnl_create_link(struct net *net, const char *ifname,
 				    unsigned char name_assign_type,
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index f98706ad390a..1bc8afcefc1e 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -2511,9 +2511,10 @@ int rtnl_nla_parse_ifinfomsg(struct nlattr **tb, const struct nlattr *nla_peer,
 }
 EXPORT_SYMBOL(rtnl_nla_parse_ifinfomsg);
 
-struct net *rtnl_link_get_net(struct net *src_net, struct nlattr *tb[])
+struct net *rtnl_link_get_net_tb(struct nlattr *tb[])
 {
-	struct net *net;
+	struct net *net = NULL;
+
 	/* Examine the link attributes and figure out which
 	 * network namespace we are talking about.
 	 */
@@ -2521,8 +2522,18 @@ struct net *rtnl_link_get_net(struct net *src_net, struct nlattr *tb[])
 		net = get_net_ns_by_pid(nla_get_u32(tb[IFLA_NET_NS_PID]));
 	else if (tb[IFLA_NET_NS_FD])
 		net = get_net_ns_by_fd(nla_get_u32(tb[IFLA_NET_NS_FD]));
-	else
+
+	return net;
+}
+EXPORT_SYMBOL(rtnl_link_get_net_tb);
+
+struct net *rtnl_link_get_net(struct net *src_net, struct nlattr *tb[])
+{
+	struct net *net = rtnl_link_get_net_tb(tb);
+
+	if (!net)
 		net = get_net(src_net);
+
 	return net;
 }
 EXPORT_SYMBOL(rtnl_link_get_net);
-- 
2.39.5 (Apple Git-154)