Currently these two steps are needed to create a net device with IFLA_LINK_NETNSID attr:
1. create and setup the netdev in the link netns with rtnl_create_link() 2. move it to the target netns with dev_change_net_namespace()
This has some side effects, including extra ifindex allocation, ifname validation and link notifications in link netns.
Add a netns_atomic flag, that if set to true, devices will be created in the target netns directly.
Signed-off-by: Xiao Liang shaw.leon@gmail.com --- include/net/rtnetlink.h | 3 +++ net/core/rtnetlink.c | 7 ++++--- 2 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/include/net/rtnetlink.h b/include/net/rtnetlink.h index b260c0cc9671..7e78f3952774 100644 --- a/include/net/rtnetlink.h +++ b/include/net/rtnetlink.h @@ -75,6 +75,8 @@ static inline int rtnl_msg_family(const struct nlmsghdr *nlh) * @srcu: Used internally * @kind: Identifier * @netns_refund: Physical device, move to init_net on netns exit + * @netns_atomic: Device can be created in target netns even when + * link-netns is different, avoiding netns change. * @maxtype: Highest device specific netlink attribute number * @policy: Netlink policy for device specific attribute validation * @validate: Optional validation function for netlink/changelink parameters @@ -116,6 +118,7 @@ struct rtnl_link_ops { void (*setup)(struct net_device *dev);
bool netns_refund; + bool netns_atomic; unsigned int maxtype; const struct nla_policy *policy; int (*validate)(struct nlattr *tb[], diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 8119f4ad9e5f..b0d1cbb44a03 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -3690,8 +3690,9 @@ static int rtnl_newlink_create(struct sk_buff *skb, struct ifinfomsg *ifm, name_assign_type = NET_NAME_ENUM; }
- dev = rtnl_create_link(link_net ? : tgt_net, ifname, - name_assign_type, ops, tb, extack); + dev = rtnl_create_link(!link_net || ops->netns_atomic ? + tgt_net : link_net, ifname, name_assign_type, + ops, tb, extack); if (IS_ERR(dev)) { err = PTR_ERR(dev); goto out; @@ -3711,7 +3712,7 @@ static int rtnl_newlink_create(struct sk_buff *skb, struct ifinfomsg *ifm, err = rtnl_configure_link(dev, ifm, portid, nlh); if (err < 0) goto out_unregister; - if (link_net) { + if (link_net && !ops->netns_atomic) { err = dev_change_net_namespace(dev, tgt_net, ifname); if (err < 0) goto out_unregister;