knfsd: move nfsv4 slab creation/destruction to module init/exit

We have some slabs that the nfs4 server uses to store state objects.
We're currently creating and destroying those slabs whenever the server
is brought up or down.  That seems excessive; may as well just do that
in module initialization and exit.

Also add some minor header cleanup.  (Thanks to Andrew Morton for that
and a compile fix.)

Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
Acked-by:  Neil Brown <neilb@suse.de>
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index baac89d..d135f5f 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -679,11 +679,13 @@
 	int retval;
 	printk(KERN_INFO "Installing knfsd (copyright (C) 1996 okir@monad.swb.de).\n");
 
+	retval = nfs4_state_init(); /* nfs4 locking state */
+	if (retval)
+		return retval;
 	nfsd_stat_init();	/* Statistics */
 	nfsd_cache_init();	/* RPC reply cache */
 	nfsd_export_init();	/* Exports table */
 	nfsd_lockd_init();	/* lockd->nfsd callbacks */
-	nfs4_state_init();	/* NFSv4 locking state */
 	nfsd_idmap_init();      /* Name to ID mapping */
 	if (proc_mkdir("fs/nfs", NULL)) {
 		struct proc_dir_entry *entry;
@@ -712,6 +714,7 @@
 	nfsd_stat_shutdown();
 	nfsd_lockd_shutdown();
 	nfsd_idmap_shutdown();
+	nfsd4_free_slabs();
 	unregister_filesystem(&nfsd_fs_type);
 }