From: Yury Norov <ynorov@nvidia.com>
Date: Thu, 19 Mar 2026 00:43:46 +0000 (-0400)
Subject: bitmap: test bitmap_weight() for more
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e9cf8f83c9857a32494002c72b5f6e36ff4dfcd5;p=thirdparty%2Fkernel%2Flinux.git

bitmap: test bitmap_weight() for more

Test the function for correctness when some bits are set in the last word
of bitmap beyond nbits. This is motivated by commit a9dadc1c512807f9
("powerpc/xive: Fix the size of the cpumask used in
xive_find_target_in_mask()").

Signed-off-by: Yury Norov <ynorov@nvidia.com>
---

diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c
index cd4cb36e42a51..eeb497016ed37 100644
--- a/lib/test_bitmap.c
+++ b/lib/test_bitmap.c
@@ -858,6 +858,7 @@ static void __init test_bitmap_weight(void)
 {
 	unsigned int bit, w1, w2, w;
 	DECLARE_BITMAP(b, 30);
+	DECLARE_BITMAP(b1, 128);
 
 	bitmap_parselist("all:1/2", b, 30);
 
@@ -877,6 +878,24 @@ static void __init test_bitmap_weight(void)
 		w2 = bitmap_weight_from(exp1, bit, EXP1_IN_BITS);
 		expect_eq_uint(w1 + w2, w);
 	}
+
+	/* Test out-of-range */
+	w = bitmap_weight_from(b, 31, 30);
+	expect_eq_uint(0, !!(w < 30));
+
+	/*
+	 * Test bitmap_weight() for correctness in case of some bits set between
+	 * nbits and end of the last word.
+	 */
+	bitmap_fill(b1, 128);
+
+	/* Inline */
+	expect_eq_uint(30, bitmap_weight(b1, 30));
+	expect_eq_uint(100, bitmap_weight(b1, 100));
+
+	/* Outline */
+	for (int i  = 1; i < 128; i++)
+		expect_eq_uint(i, bitmap_weight(b1, i));
 }
 
 static void __init test_for_each_clear_bit(void)