dns/zt.c: use isc_refcount_t for reference counting

diff --git a/lib/dns/zt.c b/lib/dns/zt.c
index cb97bcac8acf68fe4a7cd1c419e482309f462b68..6e813a979f4bfbf29d9b601bbcc2c65dabbe04a2 100644 (file)
--- a/lib/dns/zt.c
+++ b/lib/dns/zt.c
@@ -45,9 +45,9 @@ struct dns_zt {
        dns_zt_allloaded_t      loaddone;
        void *                  loaddone_arg;
        struct zt_load_params   *loadparams;
+       isc_refcount_t          references;
        /* Locked by lock. */
        bool            flush;
-       uint32_t                references;
        unsigned int            loads_pending;
        dns_rbt_t               *table;
 };
@@ -93,7 +93,7 @@ dns_zt_create(isc_mem_t *mctx, dns_rdataclass_t rdclass, dns_zt_t **ztp) {
 
        zt->mctx = NULL;
        isc_mem_attach(mctx, &zt->mctx);
-       zt->references = 1;
+       isc_refcount_init(&zt->references, 1);
        zt->flush = false;
        zt->rdclass = rdclass;
        zt->magic = ZTMAGIC;
@@ -209,13 +209,7 @@ dns_zt_attach(dns_zt_t *zt, dns_zt_t **ztp) {
        REQUIRE(VALID_ZT(zt));
        REQUIRE(ztp != NULL && *ztp == NULL);
 
-       RWLOCK(&zt->rwlock, isc_rwlocktype_write);
-
-       INSIST(zt->references > 0);
-       zt->references++;
-       INSIST(zt->references != 0);
-
-       RWUNLOCK(&zt->rwlock, isc_rwlocktype_write);
+       isc_refcount_increment(&zt->references);
 
        *ztp = zt;
 }
@@ -238,26 +232,17 @@ zt_destroy(dns_zt_t *zt) {
 
 static void
 zt_flushanddetach(dns_zt_t **ztp, bool need_flush) {
-       bool destroy = false;
        dns_zt_t *zt;
 
        REQUIRE(ztp != NULL && VALID_ZT(*ztp));
 
        zt = *ztp;
-
-       RWLOCK(&zt->rwlock, isc_rwlocktype_write);
-
-       INSIST(zt->references > 0);
-       zt->references--;
-       if (zt->references == 0)
-               destroy = true;
-       if (need_flush)
+       if (need_flush) {
                zt->flush = true;
-
-       RWUNLOCK(&zt->rwlock, isc_rwlocktype_write);
-
-       if (destroy)
+       }
+       if (isc_refcount_decrement(&zt->references) == 1) {
                zt_destroy(zt);
+       }
 
        *ztp = NULL;
 }
@@ -340,15 +325,13 @@ asyncload(dns_zone_t *zone, void *zt_) {
        isc_result_t result;
        struct dns_zt *zt = (dns_zt_t*) zt_;
        REQUIRE(zone != NULL);
-       INSIST(zt->references > 0);
-       zt->references++;
+       INSIST(isc_refcount_increment(&zt->references) > 0);
        zt->loads_pending++;
 
        result = dns_zone_asyncload(zone, zt->loadparams->newonly, *zt->loadparams->dl, zt);
        if (result != ISC_R_SUCCESS) {
-               zt->references--;
+               INSIST(isc_refcount_decrement(&zt->references) > 1);
                zt->loads_pending--;
-               INSIST(zt->references > 0);
        }
        return (ISC_R_SUCCESS);
 }
@@ -548,10 +531,9 @@ doneloading(dns_zt_t *zt, dns_zone_t *zone, isc_task_t *task) {
 
        RWLOCK(&zt->rwlock, isc_rwlocktype_write);
        INSIST(zt->loads_pending != 0);
-       INSIST(zt->references != 0);
-       zt->references--;
-       if (zt->references == 0)
+       if (isc_refcount_decrement(&zt->references) == 1) {
                destroy = true;
+       }
        zt->loads_pending--;
        if (zt->loads_pending == 0) {
                alldone = zt->loaddone;