llist-return-whether-list-is-empty-before-adding-in-llist_add-fix

[pandora-kernel.git] / include / linux / llist.h

diff --git a/include/linux/llist.h b/include/linux/llist.h
index 3eccdfd..801b44b 100644 (file)
--- a/include/linux/llist.h
+++ b/include/linux/llist.h
@@ -35,8 +35,8 @@
  *
  * The basic atomic operation of this list is cmpxchg on long.  On
  * architectures that don't have NMI-safe cmpxchg implementation, the
- * list can NOT be used in NMI handler.  So code uses the list in NMI
- * handler should depend on CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG.
+ * list can NOT be used in NMI handlers.  So code that uses the list in
+ * an NMI handler should depend on CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG.
  *
  * Copyright 2010,2011 Intel Corp.
  *   Author: Huang Ying <ying.huang@intel.com>
@@ -138,25 +138,32 @@ static inline bool llist_empty(const struct llist_head *head)
        return ACCESS_ONCE(head->first) == NULL;
 }
 
+static inline struct llist_node *llist_next(struct llist_node *node)
+{
+       return node->next;
+}
+
 /**
  * llist_add - add a new entry
  * @new:       new entry to be added
  * @head:      the head for your lock-less list
+ *
+ * Returns true if the list was empty prior to adding this entry.
  */
-static inline void llist_add(struct llist_node *new, struct llist_head *head)
+static inline bool llist_add(struct llist_node *new, struct llist_head *head)
 {
        struct llist_node *entry, *old_entry;
 
-#ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
-       BUG_ON(in_nmi());
-#endif
-
        entry = head->first;
-       do {
+       for (;;) {
                old_entry = entry;
                new->next = entry;
-               cpu_relax();
-       } while ((entry = cmpxchg(&head->first, old_entry, new)) != old_entry);
+               entry = cmpxchg(&head->first, old_entry, new);
+               if (entry == old_entry)
+                       break;
+       }
+
+       return old_entry == NULL;
 }
 
 /**
@@ -169,10 +176,12 @@ static inline void llist_add(struct llist_node *new, struct llist_head *head)
  */
 static inline struct llist_node *llist_del_all(struct llist_head *head)
 {
-#ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
-       BUG_ON(in_nmi());
-#endif
-
        return xchg(&head->first, NULL);
 }
+
+extern bool llist_add_batch(struct llist_node *new_first,
+                           struct llist_node *new_last,
+                           struct llist_head *head);
+extern struct llist_node *llist_del_first(struct llist_head *head);
+
 #endif /* LLIST_H */