X-Git-Url: http://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Flist%2Flist.h;h=a4c21f189739a2b498b7487c70e454e4024c131e;hp=90989c5fc04b6bd8436361dcda42f8f5f0ce7853;hb=82cdf817001422b742abbefa30fd540bb2a49ec4;hpb=0201703d51e85e5c3eeeef558176c1ed61369ad8

diff --git a/ccan/list/list.h b/ccan/list/list.h
index 90989c5f..a4c21f18 100644
--- a/ccan/list/list.h
+++ b/ccan/list/list.h
@@ -95,8 +95,8 @@ struct list_node *list_check_node(const struct list_node *n,
 #define list_debug(h, loc) list_check((h), loc)
 #define list_debug_node(n, loc) list_check_node((n), loc)
 #else
-#define list_debug(h, loc) (h)
-#define list_debug_node(n, loc) (n)
+#define list_debug(h, loc) ((void)loc, h)
+#define list_debug_node(n, loc) ((void)loc, n)
 #endif
 
 /**
@@ -111,7 +111,7 @@ struct list_node *list_check_node(const struct list_node *n,
  * Example:
  *	static struct list_head my_list = LIST_HEAD_INIT(my_list);
  */
-#define LIST_HEAD_INIT(name) { { &name.n, &name.n } }
+#define LIST_HEAD_INIT(name) { { &(name).n, &(name).n } }
 
 /**
  * LIST_HEAD - define and initialize an empty list_head
@@ -291,6 +291,21 @@ static inline bool list_empty_nodebug(const struct list_head *h)
 }
 #endif
 
+/**
+ * list_empty_nocheck - is a list empty?
+ * @h: the list_head
+ *
+ * If the list is empty, returns true. This doesn't perform any
+ * debug check for list consistency, so it can be called without
+ * locks, racing with the list being modified. This is ok for
+ * checks where an incorrect result is not an issue (optimized
+ * bail out path for example).
+ */
+static inline bool list_empty_nocheck(const struct list_head *h)
+{
+	return h->n.next == &h->n;
+}
+
 /**
  * list_del - delete an entry from an (unknown) linked list.
  * @n: the list_node to delete from the list.
@@ -522,9 +537,29 @@ static inline const void *list_tail_(const struct list_head *h, size_t off)
  *		printf("Name: %s\n", child->name);
  */
 #define list_for_each_rev(h, i, member)					\
-	for (i = container_of_var(list_debug(h,	LIST_LOC)->n.prev, i, member); \
-	     &i->member != &(h)->n;					\
-	     i = container_of_var(i->member.prev, i, member))
+	list_for_each_rev_off(h, i, list_off_var_(i, member))
+
+/**
+ * list_for_each_rev_safe - iterate through a list backwards,
+ * maybe during deletion
+ * @h: the list_head
+ * @i: the structure containing the list_node
+ * @nxt: the structure containing the list_node
+ * @member: the list_node member of the structure
+ *
+ * This is a convenient wrapper to iterate @i over the entire list backwards.
+ * It's a for loop, so you can break and continue as normal.  The extra
+ * variable * @nxt is used to hold the next element, so you can delete @i
+ * from the list.
+ *
+ * Example:
+ *	struct child *next;
+ *	list_for_each_rev_safe(&parent->children, child, next, list) {
+ *		printf("Name: %s\n", child->name);
+ *	}
+ */
+#define list_for_each_rev_safe(h, i, nxt, member)			\
+	list_for_each_rev_safe_off(h, i, nxt, list_off_var_(i, member))
 
 /**
  * list_for_each_safe - iterate through a list, maybe during deletion
@@ -538,7 +573,6 @@ static inline const void *list_tail_(const struct list_head *h, size_t off)
  * @nxt is used to hold the next element, so you can delete @i from the list.
  *
  * Example:
- *	struct child *next;
  *	list_for_each_safe(&parent->children, child, next, list) {
  *		list_del(&child->list);
  *		parent->num_children--;
@@ -703,6 +737,17 @@ static inline void list_prepend_list_(struct list_head *to,
 #define list_for_each_off(h, i, off)                                    \
 	list_for_each_off_dir_((h),(i),(off),next)
 
+/**
+ * list_for_each_rev_off - iterate through a list of memory regions backwards
+ * @h: the list_head
+ * @i: the pointer to a memory region wich contains list node data.
+ * @off: offset(relative to @i) at which list node data resides.
+ *
+ * See list_for_each_off for details
+ */
+#define list_for_each_rev_off(h, i, off)                                    \
+	list_for_each_off_dir_((h),(i),(off),prev)
+
 /**
  * list_for_each_safe_off - iterate through a list of memory regions, maybe
  * during deletion
@@ -722,6 +767,25 @@ static inline void list_prepend_list_(struct list_head *to,
 #define list_for_each_safe_off(h, i, nxt, off)                          \
 	list_for_each_safe_off_dir_((h),(i),(nxt),(off),next)
 
+/**
+ * list_for_each_rev_safe_off - iterate backwards through a list of
+ * memory regions, maybe during deletion
+ * @h: the list_head
+ * @i: the pointer to a memory region wich contains list node data.
+ * @nxt: the structure containing the list_node
+ * @off: offset(relative to @i) at which list node data resides.
+ *
+ * For details see `list_for_each_rev_off' and `list_for_each_rev_safe'
+ * descriptions.
+ *
+ * Example:
+ *	list_for_each_rev_safe_off(&parent->children, child,
+ *		next, offsetof(struct child, list))
+ *		printf("Name: %s\n", child->name);
+ */
+#define list_for_each_rev_safe_off(h, i, nxt, off)                      \
+	list_for_each_safe_off_dir_((h),(i),(nxt),(off),prev)
+
 /* Other -off variants. */
 #define list_entry_off(n, type, off)		\
 	((type *)list_node_from_off_((n), (off)))