| Message ID | 20241023023146.372653-3-shaw.leon@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | net: Improve netns handling in RTNL and ip_tunnel | expand |
From: Xiao Liang <shaw.leon@gmail.com> Date: Wed, 23 Oct 2024 10:31:43 +0800 > 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() IIRC, this is to send the notification in the link netns. > > 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 e0d9a8eae6b6..59594cef2272 100644 > --- a/include/net/rtnetlink.h > +++ b/include/net/rtnetlink.h > @@ -74,6 +74,8 @@ 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 > @@ -115,6 +117,7 @@ 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 ff8d25acfc00..99250779d8ba 100644 > --- a/net/core/rtnetlink.c > +++ b/net/core/rtnetlink.c > @@ -3679,8 +3679,9 @@ 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; > @@ -3700,7 +3701,7 @@ 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 >
On Wed, Oct 23, 2024 at 12:03 PM Kuniyuki Iwashima <kuniyu@amazon.com> wrote: > > From: Xiao Liang <shaw.leon@gmail.com> > Date: Wed, 23 Oct 2024 10:31:43 +0800 > > 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() > > IIRC, this is to send the notification in the link netns. > Yes. This patch changes this behavior only when the new flag is set. I doubt if it's really necessary to send link create/delete notifications to link-netns. Also the current behavior is somewhat inconsistent, say 1) ip link add netns n1 link-netns n2 link eth0 mac0 type macvlan 2) ip -n n2 link add netns n1 link eth0 mac0 type macvlan Intuitively, the two commands are equivalent. But notification is sent only for 1.
diff --git a/include/net/rtnetlink.h b/include/net/rtnetlink.h index e0d9a8eae6b6..59594cef2272 100644 --- a/include/net/rtnetlink.h +++ b/include/net/rtnetlink.h @@ -74,6 +74,8 @@ 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 @@ -115,6 +117,7 @@ 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 ff8d25acfc00..99250779d8ba 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -3679,8 +3679,9 @@ 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; @@ -3700,7 +3701,7 @@ 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;
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(-)