lib: add module support to linked list sorting tests

Extract the linked list sorting test code into its own source file, to
allow to compile it either to a loadable module, or builtin into the
kernel.

Link: http://lkml.kernel.org/r/1488287219-15832-4-git-send-email-geert@linux-m68k.org
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 150 insertions, 0 deletions

diff --git a/lib/test_list_sort.c b/lib/test_list_sort.c
new file mode 100644
index 000000000000..28e817387b04
--- /dev/null
+++ b/lib/test_list_sort.c
@@ -0,0 +1,150 @@
+#define pr_fmt(fmt) "list_sort_test: " fmt
+
+#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 serial;
+};
+
+/* Array, containing pointers to all elements in the test list */
+static struct debug_el **elts __initdata;
+
+static int __init check(struct debug_el *ela, struct debug_el *elb)
+{
+	if (ela->serial >= TEST_LIST_LEN) {
+		pr_err("error: incorrect serial %d\n", ela->serial);
+		return -EINVAL;
+	}
+	if (elb->serial >= TEST_LIST_LEN) {
+		pr_err("error: incorrect serial %d\n", elb->serial);
+		return -EINVAL;
+	}
+	if (elts[ela->serial] != ela || elts[elb->serial] != elb) {
+		pr_err("error: phantom element\n");
+		return -EINVAL;
+	}
+	if (ela->poison1 != TEST_POISON1 || ela->poison2 != TEST_POISON2) {
+		pr_err("error: bad poison: %#x/%#x\n",
+			ela->poison1, ela->poison2);
+		return -EINVAL;
+	}
+	if (elb->poison1 != TEST_POISON1 || elb->poison2 != TEST_POISON2) {
+		pr_err("error: bad poison: %#x/%#x\n",
+			elb->poison1, elb->poison2);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int __init cmp(void *priv, struct list_head *a, 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(ela, elb);
+	return ela->value - elb->value;
+}
+
+static int __init list_sort_test(void)
+{
+	int i, count = 1, err = -ENOMEM;
+	struct debug_el *el;
+	struct list_head *cur;
+	LIST_HEAD(head);
+
+	pr_debug("start testing list_sort()\n");
+
+	elts = kcalloc(TEST_LIST_LEN, sizeof(*elts), GFP_KERNEL);
+	if (!elts) {
+		pr_err("error: cannot allocate memory\n");
+		return err;
+	}
+
+	for (i = 0; i < TEST_LIST_LEN; i++) {
+		el = kmalloc(sizeof(*el), GFP_KERNEL);
+		if (!el) {
+			pr_err("error: cannot allocate memory\n");
+			goto exit;
+		}
+		 /* force some equivalencies */
+		el->value = prandom_u32() % (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(NULL, &head, cmp);
+
+	err = -EINVAL;
+	for (cur = head.next; cur->next != &head; cur = cur->next) {
+		struct debug_el *el1;
+		int cmp_result;
+
+		if (cur->next->prev != cur) {
+			pr_err("error: list is corrupted\n");
+			goto exit;
+		}
+
+		cmp_result = cmp(NULL, cur, cur->next);
+		if (cmp_result > 0) {
+			pr_err("error: list is not sorted\n");
+			goto exit;
+		}
+
+		el = container_of(cur, struct debug_el, list);
+		el1 = container_of(cur->next, struct debug_el, list);
+		if (cmp_result == 0 && el->serial >= el1->serial) {
+			pr_err("error: order of equivalent elements not "
+				"preserved\n");
+			goto exit;
+		}
+
+		if (check(el, el1)) {
+			pr_err("error: element check failed\n");
+			goto exit;
+		}
+		count++;
+	}
+	if (head.prev != cur) {
+		pr_err("error: list is corrupted\n");
+		goto exit;
+	}
+
+
+	if (count != TEST_LIST_LEN) {
+		pr_err("error: bad list length %d", count);
+		goto exit;
+	}
+
+	err = 0;
+exit:
+	for (i = 0; i < TEST_LIST_LEN; i++)
+		kfree(elts[i]);
+	kfree(elts);
+	return err;
+}
+module_init(list_sort_test);
+MODULE_LICENSE("GPL");