From 192ac21a3c057c5dedca4cdd1bf700f38992030c Mon Sep 17 00:00:00 2001
Message-Id: <192ac21a3c057c5dedca4cdd1bf700f38992030c.1496667760.git.jstancek@redhat.com>
From: Jan Stancek <jstancek@redhat.com>
Date: Thu, 1 Jun 2017 09:48:41 +0200
Subject: [PATCH v2 1/2] testutils: fix range_is_mapped()

It doesn't return correct value when tested region is
completely inside existing mapping:

  +--------------------------------------+
  ^ start                                ^ end
           +----------------+
           ^ low            ^ high

Rather than testing for all combinations of 2 regions overlapping,
flip the condition and test if they don't overlap.

Signed-off-by: Jan Stancek <jstancek@redhat.com>
---
 tests/testutils.c | 22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)

This is a v2 series for:
  https://groups.google.com/forum/#!topic/libhugetlbfs/tAsWjuJ7x8k

diff --git a/tests/testutils.c b/tests/testutils.c
index 629837045465..f42852e1938b 100644
--- a/tests/testutils.c
+++ b/tests/testutils.c
@@ -190,19 +190,29 @@ int range_is_mapped(unsigned long low, unsigned long high)
 			return -1;
 		}
 
-		if ((start >= low) && (start < high)) {
+		/*
+		 * (existing mapping)    (tested region)
+		 * +----------------+      +.......+
+		 * ^start           ^end   ^ low   ^high
+		 */
+		if (low >= end) {
 			fclose(f);
-			return 1;
+			return 0;
 		}
-		if ((end >= low) && (end < high)) {
+
+		/*
+		 * (tested region)  (existing mapping)
+		 *     +.....+      +----------------+
+		 *     ^low  ^high  ^ start          ^end
+		 */
+		if (high <= start) {
 			fclose(f);
-			return 1;
+			return 0;
 		}
-
 	}
 
 	fclose(f);
-	return 0;
+	return 1;
 }
 
 /*
-- 
1.8.3.1