From: Ondřej Surý <ondrej@sury.org>
Date: Tue, 23 Jul 2019 14:14:14 +0000 (-0400)
Subject: Use C11 atomics for nfctx, kill unused dns_resolver_nrunning()
X-Git-Tag: v9.15.8~10^2~11
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7dfc092f06442de12731e7a39c544501b80989f4;p=thirdparty%2Fbind9.git

Use C11 atomics for nfctx, kill unused dns_resolver_nrunning()
---

diff --git a/lib/dns/include/dns/resolver.h b/lib/dns/include/dns/resolver.h
index 57fa237e584..c6b26914ede 100644
--- a/lib/dns/include/dns/resolver.h
+++ b/lib/dns/include/dns/resolver.h
@@ -440,16 +440,6 @@ dns_resolver_setlamettl(dns_resolver_t *resolver, uint32_t lame_ttl);
  *\li	'resolver' to be valid.
  */
 
-unsigned int
-dns_resolver_nrunning(dns_resolver_t *resolver);
-/*%<
- * Return the number of currently running resolutions in this
- * resolver.  This is may be less than the number of outstanding
- * fetches due to multiple identical fetches, or more than the
- * number of of outstanding fetches due to the fact that resolution
- * can continue even though a fetch has been canceled.
- */
-
 isc_result_t
 dns_resolver_addalternate(dns_resolver_t *resolver, const isc_sockaddr_t *alt,
 			  const dns_name_t *name, in_port_t port);
diff --git a/lib/dns/resolver.c b/lib/dns/resolver.c
index 6fce5cd6c9b..c56d320445f 100644
--- a/lib/dns/resolver.c
+++ b/lib/dns/resolver.c
@@ -539,7 +539,7 @@ struct dns_resolver {
 	dns_fetch_t *			primefetch;
 
 	/* Atomic. */
-	isc_refcount_t			nfctx;
+	atomic_uint_fast32_t		nfctx;
 };
 
 #define RES_MAGIC			ISC_MAGIC('R', 'e', 's', '!')
@@ -4322,7 +4322,7 @@ fctx_unlink(fetchctx_t *fctx) {
 
 	ISC_LIST_UNLINK(res->buckets[bucketnum].fctxs, fctx, link);
 
-	isc_refcount_decrement(&res->nfctx);
+	REQUIRE(atomic_fetch_sub_release(&res->nfctx, 1) > 0);
 
 	dec_stats(res, dns_resstatscounter_nfetch);
 
@@ -4650,7 +4650,7 @@ fctx_start(isc_task_t *task, isc_event_t *event) {
 		else
 			fctx_try(fctx, false, false);
 	} else if (dodestroy) {
-			fctx_destroy(fctx);
+		fctx_destroy(fctx);
 		if (bucket_empty)
 			empty_bucket(res);
 	}
@@ -5015,7 +5015,7 @@ fctx_create(dns_resolver_t *res, const dns_name_t *name, dns_rdatatype_t type,
 
 	ISC_LIST_APPEND(res->buckets[bucketnum].fctxs, fctx, link);
 
-	isc_refcount_increment(&res->nfctx);
+	REQUIRE(atomic_fetch_add_relaxed(&res->nfctx, 1) < UINT32_MAX);
 
 	inc_stats(res, dns_resstatscounter_nfetch);
 
@@ -6986,7 +6986,7 @@ static void
 fctx_increference(fetchctx_t *fctx) {
 	REQUIRE(VALID_FCTX(fctx));
 
-	isc_refcount_increment(&fctx->references);
+	isc_refcount_increment0(&fctx->references);
 }
 
 /*
@@ -9799,7 +9799,7 @@ destroy(dns_resolver_t *res) {
 
 	RTRACE("destroy");
 
-	isc_refcount_destroy(&res->nfctx);
+	REQUIRE(atomic_load_acquire(&res->nfctx) == 0);
 
 	isc_mutex_destroy(&res->primelock);
 	isc_mutex_destroy(&res->lock);
@@ -10045,7 +10045,7 @@ dns_resolver_create(dns_view_t *view,
 	res->priming = false;
 	res->primefetch = NULL;
 
-	isc_refcount_init(&res->nfctx, 0);
+	atomic_init(&res->nfctx, 0);
 
 	isc_mutex_init(&res->lock);
 	isc_mutex_init(&res->primelock);
@@ -10805,11 +10805,6 @@ dns_resolver_setlamettl(dns_resolver_t *resolver, uint32_t lame_ttl) {
 	resolver->lame_ttl = lame_ttl;
 }
 
-unsigned int
-dns_resolver_nrunning(dns_resolver_t *resolver) {
-	return (isc_refcount_current(&resolver->nfctx));
-}
-
 isc_result_t
 dns_resolver_addalternate(dns_resolver_t *resolver, const isc_sockaddr_t *alt,
 			  const dns_name_t *name, in_port_t port) {
diff --git a/lib/dns/win32/libdns.def.in b/lib/dns/win32/libdns.def.in
index d77368debbd..65c4a7ddeca 100644
--- a/lib/dns/win32/libdns.def.in
+++ b/lib/dns/win32/libdns.def.in
@@ -933,7 +933,6 @@ dns_resolver_gettimeout
 dns_resolver_getudpsize
 dns_resolver_getzeronosoattl
 dns_resolver_logfetch
-dns_resolver_nrunning
 dns_resolver_prime
 dns_resolver_printbadcache
 dns_resolver_reset_algorithms