From 3fcf98c8d3ddce418ffebf7bec161a52bb4dd154 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Witold=20Kr=C4=99cicki?= <wpk@isc.org>
Date: Thu, 16 May 2019 19:27:01 +0200
Subject: [PATCH] isc/stats: use isc_refcount_t

---
 lib/ns/stats.c | 23 +++++------------------
 1 file changed, 5 insertions(+), 18 deletions(-)

diff --git a/lib/ns/stats.c b/lib/ns/stats.c
index 8a39a84940..4c558275e9 100644
--- a/lib/ns/stats.c
+++ b/lib/ns/stats.c
@@ -13,6 +13,7 @@
 
 #include <isc/magic.h>
 #include <isc/mem.h>
+#include <isc/refcount.h>
 #include <isc/stats.h>
 #include <isc/util.h>
 
@@ -22,14 +23,10 @@
 #define NS_STATS_VALID(x)		ISC_MAGIC_VALID(x, NS_STATS_MAGIC)
 
 struct ns_stats {
-	/*% Unlocked */
 	unsigned int	magic;
 	isc_mem_t	*mctx;
-	isc_mutex_t	lock;
 	isc_stats_t	*counters;
-
-	/*%  Locked by lock */
-	unsigned int	references;
+	isc_refcount_t	references;
 };
 
 void
@@ -37,9 +34,7 @@ ns_stats_attach(ns_stats_t *stats, ns_stats_t **statsp) {
 	REQUIRE(NS_STATS_VALID(stats));
 	REQUIRE(statsp != NULL && *statsp == NULL);
 
-	LOCK(&stats->lock);
-	stats->references++;
-	UNLOCK(&stats->lock);
+	isc_refcount_increment(&stats->references);
 
 	*statsp = stats;
 }
@@ -53,13 +48,8 @@ ns_stats_detach(ns_stats_t **statsp) {
 	stats = *statsp;
 	*statsp = NULL;
 
-	LOCK(&stats->lock);
-	stats->references--;
-	UNLOCK(&stats->lock);
-
-	if (stats->references == 0) {
+	if (isc_refcount_decrement(&stats->references) == 1) {
 		isc_stats_detach(&stats->counters);
-		isc_mutex_destroy(&stats->lock);
 		isc_mem_putanddetach(&stats->mctx, stats, sizeof(*stats));
 	}
 }
@@ -76,9 +66,7 @@ ns_stats_create(isc_mem_t *mctx, int ncounters, ns_stats_t **statsp) {
 		return (ISC_R_NOMEMORY);
 
 	stats->counters = NULL;
-	stats->references = 1;
-
-	isc_mutex_init(&stats->lock);
+	atomic_init(&stats->references, 1);
 
 	result = isc_stats_create(mctx, &stats->counters, ncounters);
 	if (result != ISC_R_SUCCESS)
@@ -92,7 +80,6 @@ ns_stats_create(isc_mem_t *mctx, int ncounters, ns_stats_t **statsp) {
 	return (ISC_R_SUCCESS);
 
   clean_mutex:
-	isc_mutex_destroy(&stats->lock);
 	isc_mem_put(mctx, stats, sizeof(*stats));
 
 	return (result);