[PATCH net-next 2/2] addrlabel: add/delete/get can run without rtnl

[Florian Westphal]

There appears to be no need to use rtnl, addrlabel entries are refcounted
and add/delete is serialized by the addrlabel table spinlock.

Signed-off-by: Florian Westphal <f...@strlen.de>
---
 net/ipv6/addrlabel.c | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/net/ipv6/addrlabel.c b/net/ipv6/addrlabel.c
index cea5eb488013..b055bc79f56d 100644
--- a/net/ipv6/addrlabel.c
+++ b/net/ipv6/addrlabel.c
@@ -405,6 +405,18 @@ static const struct nla_policy ifal_policy[IFAL_MAX+1] = {
        [IFAL_LABEL]            = { .len = sizeof(u32), },
 };
 
+static bool addrlbl_ifindex_exists(struct net *net, int ifindex)
+{
+
+       struct net_device *dev;
+
+       rcu_read_lock();
+       dev = dev_get_by_index_rcu(net, ifindex);
+       rcu_read_unlock();
+
+       return dev != NULL;
+}
+
 static int ip6addrlbl_newdel(struct sk_buff *skb, struct nlmsghdr *nlh,
                             struct netlink_ext_ack *extack)
 {
@@ -439,7 +451,7 @@ static int ip6addrlbl_newdel(struct sk_buff *skb, struct 
nlmsghdr *nlh,
        switch (nlh->nlmsg_type) {
        case RTM_NEWADDRLABEL:
                if (ifal->ifal_index &&
-                   !__dev_get_by_index(net, ifal->ifal_index))
+                   !addrlbl_ifindex_exists(net, ifal->ifal_index))
                        return -EINVAL;
 
                err = ip6addrlbl_add(net, pfx, ifal->ifal_prefixlen,
@@ -548,7 +560,7 @@ static int ip6addrlbl_get(struct sk_buff *in_skb, struct 
nlmsghdr *nlh,
                return -EINVAL;
 
        if (ifal->ifal_index &&
-           !__dev_get_by_index(net, ifal->ifal_index))
+           !addrlbl_ifindex_exists(net, ifal->ifal_index))
                return -EINVAL;
 
        if (!tb[IFAL_ADDRESS])
@@ -593,10 +605,10 @@ static int ip6addrlbl_get(struct sk_buff *in_skb, struct 
nlmsghdr *nlh,
 void __init ipv6_addr_label_rtnl_register(void)
 {
        __rtnl_register(PF_INET6, RTM_NEWADDRLABEL, ip6addrlbl_newdel,
-                       NULL, 0);
+                       NULL, RTNL_FLAG_DOIT_UNLOCKED);
        __rtnl_register(PF_INET6, RTM_DELADDRLABEL, ip6addrlbl_newdel,
-                       NULL, 0);
+                       NULL, RTNL_FLAG_DOIT_UNLOCKED);
        __rtnl_register(PF_INET6, RTM_GETADDRLABEL, ip6addrlbl_get,
-                       ip6addrlbl_dump, 0);
+                       ip6addrlbl_dump, RTNL_FLAG_DOIT_UNLOCKED);
 }
 
-- 
2.13.0