rtnetlink: Move rtnl_link_ops_get() and retry to rtnl_newlink().

Currently, if neither dev nor rtnl_link_ops is found in __rtnl_newlink(),
we release RTNL and redo the whole process after request_module(), which
complicates the logic.

The ops will be RTNL-independent later.

Let's move the ops lookup to rtnl_newlink() and do the retry earlier.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 97d6ad65647c8b30b9ec9c78a94358c058f48217..e708f0852602cc85de8807290513c995a0381006 100644 (file)
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -3690,23 +3690,19 @@ out_unregister:
 }
 
 static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,
+                         const struct rtnl_link_ops *ops,
                          struct rtnl_newlink_tbs *tbs,
                          struct netlink_ext_ack *extack)
 {
        struct nlattr ** const linkinfo = tbs->linkinfo;
        struct nlattr ** const tb = tbs->tb;
        struct net *net = sock_net(skb->sk);
-       const struct rtnl_link_ops *ops;
-       char kind[MODULE_NAME_LEN];
        struct net_device *dev;
        struct ifinfomsg *ifm;
        struct nlattr **data;
        bool link_specified;
        int err;
 
-#ifdef CONFIG_MODULES
-replay:
-#endif
        ifm = nlmsg_data(nlh);
        if (ifm->ifi_index > 0) {
                link_specified = true;
@@ -3722,14 +3718,6 @@ replay:
                dev = NULL;
        }
 
-       if (linkinfo[IFLA_INFO_KIND]) {
-               nla_strscpy(kind, linkinfo[IFLA_INFO_KIND], sizeof(kind));
-               ops = rtnl_link_ops_get(kind);
-       } else {
-               kind[0] = '\0';
-               ops = NULL;
-       }
-
        data = NULL;
        if (ops) {
                if (ops->maxtype > RTNL_MAX_TYPE)
@@ -3770,16 +3758,6 @@ replay:
                return -EOPNOTSUPP;
 
        if (!ops) {
-#ifdef CONFIG_MODULES
-               if (kind[0]) {
-                       __rtnl_unlock();
-                       request_module("rtnl-link-%s", kind);
-                       rtnl_lock();
-                       ops = rtnl_link_ops_get(kind);
-                       if (ops)
-                               goto replay;
-               }
-#endif
                NL_SET_ERR_MSG(extack, "Unknown device type");
                return -EOPNOTSUPP;
        }
@@ -3790,6 +3768,7 @@ replay:
 static int rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,
                        struct netlink_ext_ack *extack)
 {
+       const struct rtnl_link_ops *ops = NULL;
        struct nlattr **tb, **linkinfo;
        struct rtnl_newlink_tbs *tbs;
        int ret;
@@ -3819,7 +3798,22 @@ static int rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,
                memset(linkinfo, 0, sizeof(tbs->linkinfo));
        }
 
-       ret = __rtnl_newlink(skb, nlh, tbs, extack);
+       if (linkinfo[IFLA_INFO_KIND]) {
+               char kind[MODULE_NAME_LEN];
+
+               nla_strscpy(kind, linkinfo[IFLA_INFO_KIND], sizeof(kind));
+               ops = rtnl_link_ops_get(kind);
+#ifdef CONFIG_MODULES
+               if (!ops) {
+                       __rtnl_unlock();
+                       request_module("rtnl-link-%s", kind);
+                       rtnl_lock();
+                       ops = rtnl_link_ops_get(kind);
+               }
+#endif
+       }
+
+       ret = __rtnl_newlink(skb, nlh, ops, tbs, extack);
 
 free:
        kfree(tbs);