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.l...@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;
--
2.47.0
