linux-kernel - [PATCH v1 2/5] lib/test_cpumask: fix cpu_possible

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Message-Id: <01cf5f4ee3a2d2ef56b19a91056496fd4d648cb1.1660068429.git.sander@svanheule.net>
Date:   Tue,  9 Aug 2022 20:08:52 +0200
From:   Sander Vanheule <sander@...nheule.net>
To:     Yury Norov <yury.norov@...il.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Rasmus Villemoes <linux@...musvillemoes.dk>
Cc:     linux-kernel@...r.kernel.org,
        Maíra Canal <mairacanal@...eup.net>,
        David Gow <davidgow@...gle.com>,
        Sander Vanheule <sander@...nheule.net>
Subject: [PATCH v1 2/5] lib/test_cpumask: fix cpu_possible_mask last test

Since cpumask_first() on the cpu_possible_mask must return at most
nr_cpu_ids - 1 for a valid result, cpumask_last() cannot return anything
larger than this value.  As test_cpumask_weight() also verifies that the
total weight of cpu_possible_mask must equal nr_cpu_ids, the last bit
set in this mask must be at nr_cpu_ids - 1.

Fixes: c41e8866c28c ("lib/test: introduce cpumask KUnit test suite")
Link: https://lore.kernel.org/lkml/346cb279-8e75-24b0-7d12-9803f2b41c73@riseup.net/
Reported-by: Maíra Canal <mairacanal@...eup.net>
Signed-off-by: Sander Vanheule <sander@...nheule.net>
Cc: David Gow <davidgow@...gle.com>
---
 lib/test_cpumask.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/test_cpumask.c b/lib/test_cpumask.c
index 4ebf9f5805f3..4d353614d853 100644
--- a/lib/test_cpumask.c
+++ b/lib/test_cpumask.c
@@ -73,7 +73,7 @@ static void test_cpumask_first(struct kunit *test)
 static void test_cpumask_last(struct kunit *test)
 {
 	KUNIT_EXPECT_LE(test, nr_cpumask_bits, cpumask_last(&mask_empty));
-	KUNIT_EXPECT_EQ(test, nr_cpumask_bits - 1, cpumask_last(cpu_possible_mask));
+	KUNIT_EXPECT_EQ(test, nr_cpu_ids - 1, cpumask_last(cpu_possible_mask));
 }
 
 static void test_cpumask_next(struct kunit *test)
-- 
2.37.1