nfsd/sunrpc: add a new svc_serv_ops struct and move sv_shutdown into it

In later patches we'll need to abstract out more operations on a
per-service level, besides sv_shutdown and sv_function.

Declare a new svc_serv_ops struct to hold these operations, and move
sv_shutdown into this struct.

Signed-off-by: Shirley Ma <shirley.ma@oracle.com>
Acked-by: Jeff Layton <jlayton@primarydata.com>
Tested-by: Shirley Ma <shirley.ma@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfs/callback.c b/fs/nfs/callback.c
index 682529c..182792d 100644
--- a/fs/nfs/callback.c
+++ b/fs/nfs/callback.c
@@ -308,6 +308,9 @@
 	return ret;
 }
 
+static struct svc_serv_ops nfs_cb_sv_ops = {
+};
+
 static struct svc_serv *nfs_callback_create_svc(int minorversion)
 {
 	struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
@@ -333,7 +336,7 @@
 		printk(KERN_WARNING "nfs_callback_create_svc: no kthread, %d users??\n",
 			cb_info->users);
 
-	serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL);
+	serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, &nfs_cb_sv_ops);
 	if (!serv) {
 		printk(KERN_ERR "nfs_callback_create_svc: create service failed\n");
 		return ERR_PTR(-ENOMEM);