phonet: Don't hold RTNL for route_doit().

Now only __dev_get_by_index() depends on RTNL in route_doit().

Let's use dev_get_by_index_rcu() and register route_doit() with
RTNL_FLAG_DOIT_UNLOCKED.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/net/phonet/pn_netlink.c b/net/phonet/pn_netlink.c
index bfec5bd639b64043b979d1e8f52e8f4561d660f6..ca1f04e4a2d9eb3b2a6d6cc5b299aee28d569b08 100644 (file)
--- a/net/phonet/pn_netlink.c
+++ b/net/phonet/pn_netlink.c
@@ -245,8 +245,6 @@ static int route_doit(struct sk_buff *skb, struct nlmsghdr *nlh,
        if (!netlink_capable(skb, CAP_SYS_ADMIN))
                return -EPERM;
 
-       ASSERT_RTNL();
-
        err = nlmsg_parse_deprecated(nlh, sizeof(*rtm), tb, RTA_MAX,
                                     rtm_phonet_policy, extack);
        if (err < 0)
@@ -262,16 +260,25 @@ static int route_doit(struct sk_buff *skb, struct nlmsghdr *nlh,
                return -EINVAL;
 
        ifindex = nla_get_u32(tb[RTA_OIF]);
-       dev = __dev_get_by_index(net, ifindex);
-       if (dev == NULL)
+
+       rcu_read_lock();
+
+       dev = dev_get_by_index_rcu(net, ifindex);
+       if (!dev) {
+               rcu_read_unlock();
                return -ENODEV;
+       }
 
        if (nlh->nlmsg_type == RTM_NEWROUTE)
                err = phonet_route_add(dev, dst);
        else
                err = phonet_route_del(dev, dst);
+
+       rcu_read_unlock();
+
        if (!err)
                rtm_phonet_notify(net, nlh->nlmsg_type, ifindex, dst);
+
        return err;
 }
 
@@ -308,9 +315,9 @@ static const struct rtnl_msg_handler phonet_rtnl_msg_handlers[] __initdata_or_mo
        {.owner = THIS_MODULE, .protocol = PF_PHONET, .msgtype = RTM_GETADDR,
         .dumpit = getaddr_dumpit, .flags = RTNL_FLAG_DUMP_UNLOCKED},
        {.owner = THIS_MODULE, .protocol = PF_PHONET, .msgtype = RTM_NEWROUTE,
-        .doit = route_doit},
+        .doit = route_doit, .flags = RTNL_FLAG_DOIT_UNLOCKED},
        {.owner = THIS_MODULE, .protocol = PF_PHONET, .msgtype = RTM_DELROUTE,
-        .doit = route_doit},
+        .doit = route_doit, .flags = RTNL_FLAG_DOIT_UNLOCKED},
        {.owner = THIS_MODULE, .protocol = PF_PHONET, .msgtype = RTM_GETROUTE,
         .dumpit = route_dumpit, .flags = RTNL_FLAG_DUMP_UNLOCKED},
 };