diff --git a/src/hlua.c b/src/hlua.c
index 592a0ab..af24004 100644
--- a/src/hlua.c
+++ b/src/hlua.c
@@ -4555,7 +4555,7 @@
 	int l = MAY_LJMP(luaL_checkinteger(L, 3));
 	int max;
 
-	max = htx_free_data_space(htx);
+	max = htx_get_max_blksz(htx, channel_htx_recv_max(res, htx));
 	if (!max)
 		goto snd_yield;