1 files changed, 124 insertions, 50 deletions

diff --git a/lib/list_sort.c b/lib/list_sort.c
index 4b5cb794c38..d7325c6b103 100644
--- a/lib/list_sort.c
+++ b/lib/list_sort.c
@@ -70,7 +70,7 @@ static void merge_and_restore_back_links(void *priv,
 		 * element comparison is needed, so the client's cmp()
 		 * routine can invoke cond_resched() periodically.
 		 */
-		(*cmp)(priv, tail, tail);
+		(*cmp)(priv, tail->next, tail->next);
 
 		tail->next->prev = tail;
 		tail = tail->next;
@@ -141,77 +141,151 @@ void list_sort(void *priv, struct list_head *head,
 }
 EXPORT_SYMBOL(list_sort);
 
-#ifdef DEBUG_LIST_SORT
+#ifdef CONFIG_TEST_LIST_SORT
+
+#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 {
-	struct list_head l_h;
+	unsigned int poison1;
+	struct list_head list;
+	unsigned int poison2;
 	int value;
 	unsigned serial;
 };
 
-static int cmp(void *priv, struct list_head *a, struct list_head *b)
+/* 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)
 {
-	return container_of(a, struct debug_el, l_h)->value
-	     - container_of(b, struct debug_el, l_h)->value;
+	if (ela->serial >= TEST_LIST_LEN) {
+		printk(KERN_ERR "list_sort_test: error: incorrect serial %d\n",
+				ela->serial);
+		return -EINVAL;
+	}
+	if (elb->serial >= TEST_LIST_LEN) {
+		printk(KERN_ERR "list_sort_test: error: incorrect serial %d\n",
+				elb->serial);
+		return -EINVAL;
+	}
+	if (elts[ela->serial] != ela || elts[elb->serial] != elb) {
+		printk(KERN_ERR "list_sort_test: error: phantom element\n");
+		return -EINVAL;
+	}
+	if (ela->poison1 != TEST_POISON1 || ela->poison2 != TEST_POISON2) {
+		printk(KERN_ERR "list_sort_test: error: bad poison: %#x/%#x\n",
+				ela->poison1, ela->poison2);
+		return -EINVAL;
+	}
+	if (elb->poison1 != TEST_POISON1 || elb->poison2 != TEST_POISON2) {
+		printk(KERN_ERR "list_sort_test: error: bad poison: %#x/%#x\n",
+				elb->poison1, elb->poison2);
+		return -EINVAL;
+	}
+	return 0;
 }
 
-/*
- * The pattern of set bits in the list length determines which cases
- * are hit in list_sort().
- */
-#define LIST_SORT_TEST_LENGTH (512+128+2) /* not including head */
+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, r = 1, count;
-	struct list_head *head = kmalloc(sizeof(*head), GFP_KERNEL);
-	struct list_head *cur;
+	int i, count = 1, err = -EINVAL;
+	struct debug_el *el;
+	struct list_head *cur, *tmp;
+	LIST_HEAD(head);
+
+	printk(KERN_DEBUG "list_sort_test: start testing list_sort()\n");
 
-	printk(KERN_WARNING "testing list_sort()\n");
+	elts = kmalloc(sizeof(void *) * TEST_LIST_LEN, GFP_KERNEL);
+	if (!elts) {
+		printk(KERN_ERR "list_sort_test: error: cannot allocate "
+				"memory\n");
+		goto exit;
+	}
 
-	cur = head;
-	for (i = 0; i < LIST_SORT_TEST_LENGTH; i++) {
-		struct debug_el *el = kmalloc(sizeof(*el), GFP_KERNEL);
-		BUG_ON(!el);
+	for (i = 0; i < TEST_LIST_LEN; i++) {
+		el = kmalloc(sizeof(*el), GFP_KERNEL);
+		if (!el) {
+			printk(KERN_ERR "list_sort_test: error: cannot "
+					"allocate memory\n");
+			goto exit;
+		}
 		 /* force some equivalencies */
-		el->value = (r = (r * 725861) % 6599) % (LIST_SORT_TEST_LENGTH/3);
+		el->value = random32() % (TEST_LIST_LEN/3);
 		el->serial = i;
-
-		el->l_h.prev = cur;
-		cur->next = &el->l_h;
-		cur = cur->next;
+		el->poison1 = TEST_POISON1;
+		el->poison2 = TEST_POISON2;
+		elts[i] = el;
+		list_add_tail(&el->list, &head);
 	}
-	head->prev = cur;
 
-	list_sort(NULL, head, cmp);
+	list_sort(NULL, &head, cmp);
+
+	for (cur = head.next; cur->next != &head; cur = cur->next) {
+		struct debug_el *el1;
+		int cmp_result;
 
-	count = 1;
-	for (cur = head->next; cur->next != head; cur = cur->next) {
-		struct debug_el *el = container_of(cur, struct debug_el, l_h);
-		int cmp_result = cmp(NULL, cur, cur->next);
 		if (cur->next->prev != cur) {
-			printk(KERN_EMERG "list_sort() returned "
-						"a corrupted list!\n");
-			return 1;
-		} else if (cmp_result > 0) {
-			printk(KERN_EMERG "list_sort() failed to sort!\n");
-			return 1;
-		} else if (cmp_result == 0 &&
-				el->serial >= container_of(cur->next,
-					struct debug_el, l_h)->serial) {
-			printk(KERN_EMERG "list_sort() failed to preserve order"
-						 " of equivalent elements!\n");
-			return 1;
+			printk(KERN_ERR "list_sort_test: error: list is "
+					"corrupted\n");
+			goto exit;
+		}
+
+		cmp_result = cmp(NULL, cur, cur->next);
+		if (cmp_result > 0) {
+			printk(KERN_ERR "list_sort_test: 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) {
+			printk(KERN_ERR "list_sort_test: error: order of "
+					"equivalent elements not preserved\n");
+			goto exit;
+		}
+
+		if (check(el, el1)) {
+			printk(KERN_ERR "list_sort_test: error: element check "
+					"failed\n");
+			goto exit;
 		}
-		kfree(cur->prev);
 		count++;
 	}
-	kfree(cur);
-	if (count != LIST_SORT_TEST_LENGTH) {
-		printk(KERN_EMERG "list_sort() returned list of"
-						"different length!\n");
-		return 1;
+
+	if (count != TEST_LIST_LEN) {
+		printk(KERN_ERR "list_sort_test: error: bad list length %d",
+				count);
+		goto exit;
 	}
-	return 0;
+
+	err = 0;
+exit:
+	kfree(elts);
+	list_for_each_safe(cur, tmp, &head) {
+		list_del(cur);
+		kfree(container_of(cur, struct debug_el, list));
+	}
+	return err;
 }
 module_init(list_sort_test);
-#endif
+#endif /* CONFIG_TEST_LIST_SORT */