From d9f9b83539ab9b1ebb5cbdfa0a5a9994e20e6a0d Mon Sep 17 00:00:00 2001
From: Trond Myklebust <trond.myklebust@primarydata.com>
Date: Wed, 26 Apr 2017 11:55:26 -0400
Subject: [PATCH] SUNRPC: Refactor svc_set_num_threads()

commit 9e0d87680d689f1758185851c3da6eafb16e71e1 upstream.

Refactor to separate out the functions of starting and stopping threads
so that they can be used in other helpers.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Tested-and-reviewed-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Cc: Jan Hudoba <kernel@jahu.sk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/sunrpc/svc.c | 108 ++++++++++++++++++++++++++++-------------------
 1 file changed, 64 insertions(+), 44 deletions(-)

diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index 75f290bddca1..70c9040ed7f7 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -702,6 +702,65 @@ found_pool:
 	return task;
 }
 
+/* create new threads */
+static int
+svc_start_kthreads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
+{
+	struct svc_rqst	*rqstp;
+	struct task_struct *task;
+	struct svc_pool *chosen_pool;
+	unsigned int state = serv->sv_nrthreads-1;
+	int node;
+
+	do {
+		nrservs--;
+		chosen_pool = choose_pool(serv, pool, &state);
+
+		node = svc_pool_map_get_node(chosen_pool->sp_id);
+		rqstp = svc_prepare_thread(serv, chosen_pool, node);
+		if (IS_ERR(rqstp))
+			return PTR_ERR(rqstp);
+
+		__module_get(serv->sv_ops->svo_module);
+		task = kthread_create_on_node(serv->sv_ops->svo_function, rqstp,
+					      node, "%s", serv->sv_name);
+		if (IS_ERR(task)) {
+			module_put(serv->sv_ops->svo_module);
+			svc_exit_thread(rqstp);
+			return PTR_ERR(task);
+		}
+
+		rqstp->rq_task = task;
+		if (serv->sv_nrpools > 1)
+			svc_pool_map_set_cpumask(task, chosen_pool->sp_id);
+
+		svc_sock_update_bufs(serv);
+		wake_up_process(task);
+	} while (nrservs > 0);
+
+	return 0;
+}
+
+
+/* destroy old threads */
+static int
+svc_signal_kthreads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
+{
+	struct task_struct *task;
+	unsigned int state = serv->sv_nrthreads-1;
+
+	/* destroy old threads */
+	do {
+		task = choose_victim(serv, pool, &state);
+		if (task == NULL)
+			break;
+		send_sig(SIGINT, task, 1);
+		nrservs++;
+	} while (nrservs < 0);
+
+	return 0;
+}
+
 /*
  * Create or destroy enough new threads to make the number
  * of threads the given number.  If `pool' is non-NULL, applies
@@ -719,13 +778,6 @@ found_pool:
 int
 svc_set_num_threads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
 {
-	struct svc_rqst	*rqstp;
-	struct task_struct *task;
-	struct svc_pool *chosen_pool;
-	int error = 0;
-	unsigned int state = serv->sv_nrthreads-1;
-	int node;
-
 	if (pool == NULL) {
 		/* The -1 assumes caller has done a svc_get() */
 		nrservs -= (serv->sv_nrthreads-1);
@@ -735,43 +787,11 @@ svc_set_num_threads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
 		spin_unlock_bh(&pool->sp_lock);
 	}
 
-	/* create new threads */
-	while (nrservs > 0) {
-		nrservs--;
-		chosen_pool = choose_pool(serv, pool, &state);
-
-		node = svc_pool_map_get_node(chosen_pool->sp_id);
-		rqstp = svc_prepare_thread(serv, chosen_pool, node);
-		if (IS_ERR(rqstp)) {
-			error = PTR_ERR(rqstp);
-			break;
-		}
-
-		__module_get(serv->sv_ops->svo_module);
-		task = kthread_create_on_node(serv->sv_ops->svo_function, rqstp,
-					      node, "%s", serv->sv_name);
-		if (IS_ERR(task)) {
-			error = PTR_ERR(task);
-			module_put(serv->sv_ops->svo_module);
-			svc_exit_thread(rqstp);
-			break;
-		}
-
-		rqstp->rq_task = task;
-		if (serv->sv_nrpools > 1)
-			svc_pool_map_set_cpumask(task, chosen_pool->sp_id);
-
-		svc_sock_update_bufs(serv);
-		wake_up_process(task);
-	}
-	/* destroy old threads */
-	while (nrservs < 0 &&
-	       (task = choose_victim(serv, pool, &state)) != NULL) {
-		send_sig(SIGINT, task, 1);
-		nrservs++;
-	}
-
-	return error;
+	if (nrservs > 0)
+		return svc_start_kthreads(serv, pool, nrservs);
+	if (nrservs < 0)
+		return svc_signal_kthreads(serv, pool, nrservs);
+	return 0;
 }
 EXPORT_SYMBOL_GPL(svc_set_num_threads);