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 */