[PATCH 1/3] bitmap: test bitmap_weight() for more

Yury Norov
2026-03-19T00:43:57Z

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>
---
lib/test_bitmap.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)

diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c
index cd4cb36e42a5..eeb497016ed3 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)
--
2.43.0