nfsd/sunrpc: abstract out svc_set_num_threads to sv_ops

Add an operation that will do setup of the service. In the case of a
classic thread-based service that means starting up threads. In the case
of a workqueue-based service, the setup will do something different.
Signed-off-by: Shirley Ma <shirley.ma@oracle.com>
Acked-by: Jeff Layton <jlayton@primarydata.com>
Tested-by: Shirley Ma <shirliey.ma@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfssvc.c

@@ -395,6 +395,7 @@ static struct svc_serv_ops nfsd_thread_sv_ops = {
 	.svo_shutdown		= nfsd_last_thread,
 	.svo_function		= nfsd,
 	.svo_enqueue_xprt	= svc_xprt_do_enqueue,
+	.svo_setup		= svc_set_num_threads,
 	.svo_module		= THIS_MODULE,
 };
 
@@ -507,8 +508,8 @@ int nfsd_set_nrthreads(int n, int *nthreads, struct net *net)
 	/* apply the new numbers */
 	svc_get(nn->nfsd_serv);
 	for (i = 0; i < n; i++) {
-		err = svc_set_num_threads(nn->nfsd_serv, &nn->nfsd_serv->sv_pools[i],
-				    	  nthreads[i]);
+		err = nn->nfsd_serv->sv_ops->svo_setup(nn->nfsd_serv,
+				&nn->nfsd_serv->sv_pools[i], nthreads[i]);
 		if (err)
 			break;
 	}
@@ -547,7 +548,8 @@ nfsd_svc(int nrservs, struct net *net)
 	error = nfsd_startup_net(nrservs, net);
 	if (error)
 		goto out_destroy;
-	error = svc_set_num_threads(nn->nfsd_serv, NULL, nrservs);
+	error = nn->nfsd_serv->sv_ops->svo_setup(nn->nfsd_serv,
+			NULL, nrservs);
 	if (error)
 		goto out_shutdown;
 	/* We are holding a reference to nn->nfsd_serv which

include/linux/sunrpc/svc.h

@@ -61,6 +61,9 @@ struct svc_serv_ops {
 	/* queue up a transport for servicing */
 	void		(*svo_enqueue_xprt)(struct svc_xprt *);
 
+	/* set up thread (or whatever) execution context */
+	int		(*svo_setup)(struct svc_serv *, struct svc_pool *, int);
+
 	/* optional module to count when adding threads (pooled svcs only) */
 	struct module	*svo_module;
 };