nfsd: only register cld pipe notifier when CONFIG_NFSD_V4 is enabled

Otherwise, we get a warning or error similar to this when building with
CONFIG_NFSD_V4 disabled:

    ERROR: "nfsd4_cld_block" [fs/nfsd/nfsd.ko] undefined!

Fix this by wrapping the calls to rpc_pipefs_notifier_register and
..._unregister in another function and providing no-op replacements
when CONFIG_NFSD_V4 is disabled.

Reported-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index dee6c1bb9ba8..2c53be6d3579 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -1137,7 +1137,7 @@ static int __init init_nfsd(void)
 	int retval;
 	printk(KERN_INFO "Installing knfsd (copyright (C) 1996 okir@monad.swb.de).\n");
 
-	retval = rpc_pipefs_notifier_register(&nfsd4_cld_block);
+	retval = register_cld_notifier();
 	if (retval)
 		return retval;
 	retval = register_pernet_subsys(&nfsd_net_ops);
@@ -1186,7 +1186,7 @@ out_free_slabs:
 out_unregister_pernet:
 	unregister_pernet_subsys(&nfsd_net_ops);
 out_unregister_notifier:
-	rpc_pipefs_notifier_unregister(&nfsd4_cld_block);
+	unregister_cld_notifier();
 	return retval;
 }
 
@@ -1203,7 +1203,7 @@ static void __exit exit_nfsd(void)
 	nfsd_fault_inject_cleanup();
 	unregister_filesystem(&nfsd_fs_type);
 	unregister_pernet_subsys(&nfsd_net_ops);
-	rpc_pipefs_notifier_unregister(&nfsd4_cld_block);
+	unregister_cld_notifier();
 }
 
 MODULE_AUTHOR("Olaf Kirch <okir@monad.swb.de>");