From 26a93d77aa17bea5e0a67623558cd3cdcf10009b Mon Sep 17 00:00:00 2001
From: Mark Andrews <marka@isc.org>
Date: Mon, 25 Nov 2019 11:38:09 +1100
Subject: [PATCH] move maxbuffers test to allocate_udp_buffer

---
 lib/dns/dispatch.c | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/lib/dns/dispatch.c b/lib/dns/dispatch.c
index 2e534d26c3..c70ee9fa25 100644
--- a/lib/dns/dispatch.c
+++ b/lib/dns/dispatch.c
@@ -915,6 +915,10 @@ allocate_udp_buffer(dns_dispatch_t *disp) {
 	void *temp;
 
 	LOCK(&disp->mgr->buffer_lock);
+	if (disp->mgr->buffers >= disp->mgr->maxbuffers) {
+		UNLOCK(&disp->mgr->buffer_lock);
+		return (NULL);
+	}
 	bpool = disp->mgr->bpool;
 	disp->mgr->buffers++;
 	UNLOCK(&disp->mgr->buffer_lock);
@@ -1500,15 +1504,6 @@ startrecv(dns_dispatch_t *disp, dispsocket_t *dispsock) {
 	if (disp->recv_pending != 0 && dispsock == NULL)
 		return (ISC_R_SUCCESS);
 
-	if (disp->socktype == isc_sockettype_udp) {
-		LOCK(&disp->mgr->buffer_lock);
-		if (disp->mgr->buffers >= disp->mgr->maxbuffers) {
-			UNLOCK(&disp->mgr->buffer_lock);
-			return (ISC_R_NOMEMORY);
-		}
-		UNLOCK(&disp->mgr->buffer_lock);
-	}
-
 	if ((disp->attributes & DNS_DISPATCHATTR_EXCLUSIVE) != 0 &&
 	    dispsock == NULL)
 		return (ISC_R_SUCCESS);