1 files changed, 123 insertions, 0 deletions
diff --git a/lib/tests/test_list_sort.c b/lib/tests/test_list_sort.c
new file mode 100644
index 000000000000..30879abc8a42
--- /dev/null
+++ b/lib/tests/test_list_sort.c
@@ -0,0 +1,123 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <kunit/test.h>
+
+#include <linux/kernel.h>
+#include <linux/list_sort.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/printk.h>
+#include <linux/slab.h>
+#include <linux/random.h>
+
+/*
+ * The pattern of set bits in the list length determines which cases
+ * are hit in list_sort().
+ */
+#define TEST_LIST_LEN (512+128+2) /* not including head */
+
+#define TEST_POISON1 0xDEADBEEF
+#define TEST_POISON2 0xA324354C
+
+struct debug_el {
+	unsigned int poison1;
+	struct list_head list;
+	unsigned int poison2;
+	int value;
+	unsigned int serial;
+};
+
+static void check(struct kunit *test, struct debug_el *ela, struct debug_el *elb)
+{
+	struct debug_el **elts = test->priv;
+
+	KUNIT_EXPECT_LT_MSG(test, ela->serial, (unsigned int)TEST_LIST_LEN, "incorrect serial");
+	KUNIT_EXPECT_LT_MSG(test, elb->serial, (unsigned int)TEST_LIST_LEN, "incorrect serial");
+
+	KUNIT_EXPECT_PTR_EQ_MSG(test, elts[ela->serial], ela, "phantom element");
+	KUNIT_EXPECT_PTR_EQ_MSG(test, elts[elb->serial], elb, "phantom element");
+
+	KUNIT_EXPECT_EQ_MSG(test, ela->poison1, TEST_POISON1, "bad poison");
+	KUNIT_EXPECT_EQ_MSG(test, ela->poison2, TEST_POISON2, "bad poison");
+
+	KUNIT_EXPECT_EQ_MSG(test, elb->poison1, TEST_POISON1, "bad poison");
+	KUNIT_EXPECT_EQ_MSG(test, elb->poison2, TEST_POISON2, "bad poison");
+}
+
+/* `priv` is the test pointer so check() can fail the test if the list is invalid. */
+static int cmp(void *priv, const struct list_head *a, const struct list_head *b)
+{
+	struct debug_el *ela, *elb;
+
+	ela = container_of(a, struct debug_el, list);
+	elb = container_of(b, struct debug_el, list);
+
+	check(priv, ela, elb);
+	return ela->value - elb->value;
+}
+
+static void list_sort_test(struct kunit *test)
+{
+	int i, count = 1;
+	struct debug_el *el, **elts;
+	struct list_head *cur;
+	LIST_HEAD(head);
+
+	elts = kunit_kcalloc(test, TEST_LIST_LEN, sizeof(*elts), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, elts);
+	test->priv = elts;
+
+	for (i = 0; i < TEST_LIST_LEN; i++) {
+		el = kunit_kmalloc(test, sizeof(*el), GFP_KERNEL);
+		KUNIT_ASSERT_NOT_ERR_OR_NULL(test, el);
+
+		 /* force some equivalencies */
+		el->value = get_random_u32_below(TEST_LIST_LEN / 3);
+		el->serial = i;
+		el->poison1 = TEST_POISON1;
+		el->poison2 = TEST_POISON2;
+		elts[i] = el;
+		list_add_tail(&el->list, &head);
+	}
+
+	list_sort(test, &head, cmp);
+
+	for (cur = head.next; cur->next != &head; cur = cur->next) {
+		struct debug_el *el1;
+		int cmp_result;
+
+		KUNIT_ASSERT_PTR_EQ_MSG(test, cur->next->prev, cur,
+					"list is corrupted");
+
+		cmp_result = cmp(test, cur, cur->next);
+		KUNIT_ASSERT_LE_MSG(test, cmp_result, 0, "list is not sorted");
+
+		el = container_of(cur, struct debug_el, list);
+		el1 = container_of(cur->next, struct debug_el, list);
+		if (cmp_result == 0) {
+			KUNIT_ASSERT_LE_MSG(test, el->serial, el1->serial,
+					    "order of equivalent elements not preserved");
+		}
+
+		check(test, el, el1);
+		count++;
+	}
+	KUNIT_EXPECT_PTR_EQ_MSG(test, head.prev, cur, "list is corrupted");
+
+	KUNIT_EXPECT_EQ_MSG(test, count, TEST_LIST_LEN,
+			    "list length changed after sorting!");
+}
+
+static struct kunit_case list_sort_cases[] = {
+	KUNIT_CASE(list_sort_test),
+	{}
+};
+
+static struct kunit_suite list_sort_suite = {
+	.name = "list_sort",
+	.test_cases = list_sort_cases,
+};
+
+kunit_test_suites(&list_sort_suite);
+
+MODULE_DESCRIPTION("list_sort() KUnit test suite");
+MODULE_LICENSE("GPL");