From: Ondřej Surý <ondrej@sury.org>
Date: Fri, 9 Jul 2021 12:35:00 +0000 (+0200)
Subject: Properly disable the "water" in isc_mem
X-Git-Tag: v9.17.17~40^2~1
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=9c3bebc26f943566a685d343fcc32a0402c11f9a;p=thirdparty%2Fbind9.git

Properly disable the "water" in isc_mem

The proper way how to disable the water limit in the isc_mem context is
to call:

    isc_mem_setwater(ctx, NULL, NULL, 0, 0);

this ensures that the old water callback is called with ISC_MEM_LOWATER
if the callback was called with ISC_MEM_HIWATER before.

Historically, there were some places where the limits were disabled by
calling:

    isc_mem_setwater(ctx, water, water_arg, 0, 0);

which would also call the old callback, but it also causes the water_t
to be allocated and extra check to be executed because water callback is
not NULL.

This commits unifies the calls to disable water to the preferred form.
---

diff --git a/lib/dns/adb.c b/lib/dns/adb.c
index defb75c44ce..6b1bddad636 100644
--- a/lib/dns/adb.c
+++ b/lib/dns/adb.c
@@ -2869,7 +2869,7 @@ dns_adb_shutdown(dns_adb_t *adb) {
 
 	if (!adb->shutting_down) {
 		adb->shutting_down = true;
-		isc_mem_setwater(adb->mctx, water, adb, 0, 0);
+		isc_mem_setwater(adb->mctx, NULL, NULL, 0, 0);
 		/*
 		 * Isolate shutdown_names and shutdown_entries calls.
 		 */
@@ -4699,7 +4699,7 @@ dns_adb_setadbsize(dns_adb_t *adb, size_t size) {
 	lowater = size - (size >> 2); /* Approximately 3/4ths. */
 
 	if (size == 0U || hiwater == 0U || lowater == 0U) {
-		isc_mem_setwater(adb->mctx, water, adb, 0, 0);
+		isc_mem_setwater(adb->mctx, NULL, NULL, 0, 0);
 	} else {
 		isc_mem_setwater(adb->mctx, water, adb, hiwater, lowater);
 	}
diff --git a/lib/dns/cache.c b/lib/dns/cache.c
index 9935275d8f6..bf73300c058 100644
--- a/lib/dns/cache.c
+++ b/lib/dns/cache.c
@@ -950,7 +950,7 @@ dns_cache_setcachesize(dns_cache_t *cache, size_t size) {
 		/*
 		 * Disable cache memory limiting.
 		 */
-		isc_mem_setwater(cache->mctx, water, cache, 0, 0);
+		isc_mem_setwater(cache->mctx, NULL, NULL, 0, 0);
 	} else {
 		/*
 		 * Establish new cache memory limits (either for the first