Revert "genetlink: fix family dump race"

This reverts commit aab4f8d4, commit
58ad436f upstream, as it causes
problems.

Cc: Johannes Berg <johannes.berg@intel.com>
Cc: Andrei Otcheretianski <andrei.otcheretianski@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

net/netlink/genetlink.c

@@ -789,10 +789,6 @@ static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
 	struct net *net = sock_net(skb->sk);
 	int chains_to_skip = cb->args[0];
 	int fams_to_skip = cb->args[1];
-	bool need_locking = chains_to_skip || fams_to_skip;
-
-	if (need_locking)
-		genl_lock();
 
 	for (i = chains_to_skip; i < GENL_FAM_TAB_SIZE; i++) {
 		n = 0;
@@ -814,9 +810,6 @@ static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
 	cb->args[0] = i;
 	cb->args[1] = n;
 
-	if (need_locking)
-		genl_unlock();
-
 	return skb->len;
 }