rtnetlink: call rtnl_calcit directly

There is only a single place in the kernel that regisers the "calcit"
callback (to determine min allocation for dumps).

This is in rtnetlink.c for PF_UNSPEC RTM_GETLINK.
The function that checks for calcit presence at run time will first check
the requested family (which will always fail for !PF_UNSPEC as no callsite
registers this), then falls back to checking PF_UNSPEC.

Therefore we can just check if type is RTM_GETLINK and then do a direct
call.  Because of fallback to PF_UNSPEC all RTM_GETLINK types used this
regardless of family.

This has the advantage that we don't need to allocate space for
the function pointer for all the other families.

A followup patch will drop the calcit function pointer from the
rtnl_link callback structure.

Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 9201e3621351144f1fde497dfa1025d93d0a76f9..8c9d34deea7d0f8fff7202e9ffcffad54b04361f 100644 (file)
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -62,7 +62,6 @@
 struct rtnl_link {
        rtnl_doit_func          doit;
        rtnl_dumpit_func        dumpit;
-       rtnl_calcit_func        calcit;
 };
 
 static DEFINE_MUTEX(rtnl_mutex);
@@ -173,21 +172,6 @@ static rtnl_dumpit_func rtnl_get_dumpit(int protocol, int msgindex)
        return tab[msgindex].dumpit;
 }
 
-static rtnl_calcit_func rtnl_get_calcit(int protocol, int msgindex)
-{
-       struct rtnl_link *tab;
-
-       if (protocol <= RTNL_FAMILY_MAX)
-               tab = rtnl_msg_handlers[protocol];
-       else
-               tab = NULL;
-
-       if (tab == NULL || tab[msgindex].calcit == NULL)
-               tab = rtnl_msg_handlers[PF_UNSPEC];
-
-       return tab[msgindex].calcit;
-}
-
 /**
  * __rtnl_register - Register a rtnetlink message type
  * @protocol: Protocol family or PF_UNSPEC
@@ -231,9 +215,6 @@ int __rtnl_register(int protocol, int msgtype,
        if (dumpit)
                tab[msgindex].dumpit = dumpit;
 
-       if (calcit)
-               tab[msgindex].calcit = calcit;
-
        return 0;
 }
 EXPORT_SYMBOL_GPL(__rtnl_register);
@@ -277,7 +258,6 @@ int rtnl_unregister(int protocol, int msgtype)
 
        rtnl_msg_handlers[protocol][msgindex].doit = NULL;
        rtnl_msg_handlers[protocol][msgindex].dumpit = NULL;
-       rtnl_msg_handlers[protocol][msgindex].calcit = NULL;
 
        return 0;
 }
@@ -4187,15 +4167,14 @@ static int rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
        if (kind == 2 && nlh->nlmsg_flags&NLM_F_DUMP) {
                struct sock *rtnl;
                rtnl_dumpit_func dumpit;
-               rtnl_calcit_func calcit;
                u16 min_dump_alloc = 0;
 
                dumpit = rtnl_get_dumpit(family, type);
                if (dumpit == NULL)
                        return -EOPNOTSUPP;
-               calcit = rtnl_get_calcit(family, type);
-               if (calcit)
-                       min_dump_alloc = calcit(skb, nlh);
+
+               if (type == RTM_GETLINK)
+                       min_dump_alloc = rtnl_calcit(skb, nlh);
 
                __rtnl_unlock();
                rtnl = net->rtnl;
@@ -4300,7 +4279,7 @@ void __init rtnetlink_init(void)
        register_netdevice_notifier(&rtnetlink_dev_notifier);
 
        rtnl_register(PF_UNSPEC, RTM_GETLINK, rtnl_getlink,
-                     rtnl_dump_ifinfo, rtnl_calcit);
+                     rtnl_dump_ifinfo, NULL);
        rtnl_register(PF_UNSPEC, RTM_SETLINK, rtnl_setlink, NULL, NULL);
        rtnl_register(PF_UNSPEC, RTM_NEWLINK, rtnl_newlink, NULL, NULL);
        rtnl_register(PF_UNSPEC, RTM_DELLINK, rtnl_dellink, NULL, NULL);