1 files changed, 105 insertions, 64 deletions

diff --git a/include/linux/list.h b/include/linux/list.h
index a02642e4710a..a9c90287c0ff 100644
--- a/include/linux/list.h
+++ b/include/linux/list.h
@@ -4,18 +4,11 @@
 #ifdef __KERNEL__
 
 #include <linux/stddef.h>
+#include <linux/poison.h>
 #include <linux/prefetch.h>
 #include <asm/system.h>
 
 /*
- * These are non-NULL pointers that will result in page faults
- * under normal circumstances, used to verify that nobody uses
- * non-initialized list entries.
- */
-#define LIST_POISON1  ((void *) 0x00100100)
-#define LIST_POISON2  ((void *) 0x00200200)
-
-/*
  * Simple doubly linked list implementation.
  *
  * Some of the internal functions ("__xxx") are useful when
@@ -46,6 +39,7 @@ static inline void INIT_LIST_HEAD(struct list_head *list)
  * This is only for internal list manipulation where we know
  * the prev/next entries already!
  */
+#ifndef CONFIG_DEBUG_LIST
 static inline void __list_add(struct list_head *new,
                               struct list_head *prev,
                               struct list_head *next)
@@ -55,6 +49,11 @@ static inline void __list_add(struct list_head *new,
         new->prev = prev;
         prev->next = new;
 }
+#else
+extern void __list_add(struct list_head *new,
+                              struct list_head *prev,
+                              struct list_head *next);
+#endif
 
 /**
  * list_add - add a new entry
@@ -64,10 +63,15 @@ static inline void __list_add(struct list_head *new,
  * Insert a new entry after the specified head.
  * This is good for implementing stacks.
  */
+#ifndef CONFIG_DEBUG_LIST
 static inline void list_add(struct list_head *new, struct list_head *head)
 {
         __list_add(new, head, head->next);
 }
+#else
+extern void list_add(struct list_head *new, struct list_head *head);
+#endif
+
 
 /**
  * list_add_tail - add a new entry
@@ -160,12 +164,16 @@ static inline void __list_del(struct list_head * prev, struct list_head * next)
  * Note: list_empty on entry does not return true after this, the entry is
  * in an undefined state.
  */
+#ifndef CONFIG_DEBUG_LIST
 static inline void list_del(struct list_head *entry)
 {
         __list_del(entry->prev, entry->next);
         entry->next = LIST_POISON1;
         entry->prev = LIST_POISON2;
 }
+#else
+extern void list_del(struct list_head *entry);
+#endif
 
 /**
  * list_del_rcu - deletes entry from list without re-initialization
@@ -272,6 +280,17 @@ static inline void list_move_tail(struct list_head *list,
 }
 
 /**
+ * list_is_last - tests whether @list is the last entry in list @head
+ * @list: the entry to test
+ * @head: the head of the list
+ */
+static inline int list_is_last(const struct list_head *list,
+                                const struct list_head *head)
+{
+        return list->next == head;
+}
+
+/**
  * list_empty - tests whether a list is empty
  * @head: the list to test.
  */
@@ -281,16 +300,17 @@ static inline int list_empty(const struct list_head *head)
 }
 
 /**
- * list_empty_careful - tests whether a list is
- * empty _and_ checks that no other CPU might be
- * in the process of still modifying either member
+ * list_empty_careful - tests whether a list is empty and not being modified
+ * @head: the list to test
+ *
+ * Description:
+ * tests whether a list is empty _and_ checks that no other CPU might be
+ * in the process of modifying either member (next or prev)
  *
  * NOTE: using list_empty_careful() without synchronization
  * can only be safe if the only activity that can happen
  * to the list entry is list_del_init(). Eg. it cannot be used
  * if another CPU could re-list_add() it.
- *
- * @head: the list to test.
  */
 static inline int list_empty_careful(const struct list_head *head)
 {
@@ -350,7 +370,7 @@ static inline void list_splice_init(struct list_head *list,
 
 /**
  * list_for_each        -       iterate over a list
- * @pos:        the &struct list_head to use as a loop counter.
+ * @pos:        the &struct list_head to use as a loop cursor.
  * @head:       the head for your list.
  */
 #define list_for_each(pos, head) \
@@ -359,7 +379,7 @@ static inline void list_splice_init(struct list_head *list,
 
 /**
  * __list_for_each      -       iterate over a list
- * @pos:        the &struct list_head to use as a loop counter.
+ * @pos:        the &struct list_head to use as a loop cursor.
  * @head:       the head for your list.
  *
  * This variant differs from list_for_each() in that it's the
@@ -372,7 +392,7 @@ static inline void list_splice_init(struct list_head *list,
 
 /**
  * list_for_each_prev   -       iterate over a list backwards
- * @pos:        the &struct list_head to use as a loop counter.
+ * @pos:        the &struct list_head to use as a loop cursor.
  * @head:       the head for your list.
  */
 #define list_for_each_prev(pos, head) \
@@ -380,8 +400,8 @@ static inline void list_splice_init(struct list_head *list,
                 pos = pos->prev)
 
 /**
- * list_for_each_safe   -       iterate over a list safe against removal of list entry
- * @pos:        the &struct list_head to use as a loop counter.
+ * list_for_each_safe - iterate over a list safe against removal of list entry
+ * @pos:        the &struct list_head to use as a loop cursor.
  * @n:          another &struct list_head to use as temporary storage
  * @head:       the head for your list.
  */
@@ -391,7 +411,7 @@ static inline void list_splice_init(struct list_head *list,
 
 /**
  * list_for_each_entry  -       iterate over list of given type
- * @pos:        the type * to use as a loop counter.
+ * @pos:        the type * to use as a loop cursor.
  * @head:       the head for your list.
  * @member:     the name of the list_struct within the struct.
  */
@@ -402,7 +422,7 @@ static inline void list_splice_init(struct list_head *list,
 
 /**
  * list_for_each_entry_reverse - iterate backwards over list of given type.
- * @pos:        the type * to use as a loop counter.
+ * @pos:        the type * to use as a loop cursor.
  * @head:       the head for your list.
  * @member:     the name of the list_struct within the struct.
  */
@@ -412,21 +432,24 @@ static inline void list_splice_init(struct list_head *list,
              pos = list_entry(pos->member.prev, typeof(*pos), member))
 
 /**
- * list_prepare_entry - prepare a pos entry for use as a start point in
- *                      list_for_each_entry_continue
+ * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue
  * @pos:        the type * to use as a start point
  * @head:       the head of the list
  * @member:     the name of the list_struct within the struct.
+ *
+ * Prepares a pos entry for use as a start point in list_for_each_entry_continue.
  */
 #define list_prepare_entry(pos, head, member) \
         ((pos) ? : list_entry(head, typeof(*pos), member))
 
 /**
- * list_for_each_entry_continue -       iterate over list of given type
- *                      continuing after existing point
- * @pos:        the type * to use as a loop counter.
+ * list_for_each_entry_continue - continue iteration over list of given type
+ * @pos:        the type * to use as a loop cursor.
  * @head:       the head for your list.
  * @member:     the name of the list_struct within the struct.
+ *
+ * Continue to iterate over list of given type, continuing after
+ * the current position.
  */
 #define list_for_each_entry_continue(pos, head, member)                 \
         for (pos = list_entry(pos->member.next, typeof(*pos), member);  \
@@ -434,11 +457,12 @@ static inline void list_splice_init(struct list_head *list,
              pos = list_entry(pos->member.next, typeof(*pos), member))
 
 /**
- * list_for_each_entry_from -   iterate over list of given type
- *                      continuing from existing point
- * @pos:        the type * to use as a loop counter.
+ * list_for_each_entry_from - iterate over list of given type from the current point
+ * @pos:        the type * to use as a loop cursor.
  * @head:       the head for your list.
  * @member:     the name of the list_struct within the struct.
+ *
+ * Iterate over list of given type, continuing from current position.
  */
 #define list_for_each_entry_from(pos, head, member)                     \
         for (; prefetch(pos->member.next), &pos->member != (head);      \
@@ -446,7 +470,7 @@ static inline void list_splice_init(struct list_head *list,
 
 /**
  * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
- * @pos:        the type * to use as a loop counter.
+ * @pos:        the type * to use as a loop cursor.
  * @n:          another type * to use as temporary storage
  * @head:       the head for your list.
  * @member:     the name of the list_struct within the struct.
@@ -458,12 +482,14 @@ static inline void list_splice_init(struct list_head *list,
              pos = n, n = list_entry(n->member.next, typeof(*n), member))
 
 /**
- * list_for_each_entry_safe_continue -  iterate over list of given type
- *                      continuing after existing point safe against removal of list entry
- * @pos:        the type * to use as a loop counter.
+ * list_for_each_entry_safe_continue
+ * @pos:        the type * to use as a loop cursor.
  * @n:          another type * to use as temporary storage
  * @head:       the head for your list.
  * @member:     the name of the list_struct within the struct.
+ *
+ * Iterate over list of given type, continuing after current point,
+ * safe against removal of list entry.
  */
 #define list_for_each_entry_safe_continue(pos, n, head, member)                 \
         for (pos = list_entry(pos->member.next, typeof(*pos), member),          \
@@ -472,12 +498,14 @@ static inline void list_splice_init(struct list_head *list,
              pos = n, n = list_entry(n->member.next, typeof(*n), member))
 
 /**
- * list_for_each_entry_safe_from - iterate over list of given type
- *                      from existing point safe against removal of list entry
- * @pos:        the type * to use as a loop counter.
+ * list_for_each_entry_safe_from
+ * @pos:        the type * to use as a loop cursor.
  * @n:          another type * to use as temporary storage
  * @head:       the head for your list.
  * @member:     the name of the list_struct within the struct.
+ *
+ * Iterate over list of given type from current point, safe against
+ * removal of list entry.
  */
 #define list_for_each_entry_safe_from(pos, n, head, member)                     \
         for (n = list_entry(pos->member.next, typeof(*pos), member);            \
@@ -485,12 +513,14 @@ static inline void list_splice_init(struct list_head *list,
              pos = n, n = list_entry(n->member.next, typeof(*n), member))
 
 /**
- * list_for_each_entry_safe_reverse - iterate backwards over list of given type safe against
- *                                    removal of list entry
- * @pos:        the type * to use as a loop counter.
+ * list_for_each_entry_safe_reverse
+ * @pos:        the type * to use as a loop cursor.
  * @n:          another type * to use as temporary storage
  * @head:       the head for your list.
  * @member:     the name of the list_struct within the struct.
+ *
+ * Iterate backwards over list of given type, safe against removal
+ * of list entry.
  */
 #define list_for_each_entry_safe_reverse(pos, n, head, member)          \
         for (pos = list_entry((head)->prev, typeof(*pos), member),      \
@@ -500,7 +530,7 @@ static inline void list_splice_init(struct list_head *list,
 
 /**
  * list_for_each_rcu    -       iterate over an rcu-protected list
- * @pos:        the &struct list_head to use as a loop counter.
+ * @pos:        the &struct list_head to use as a loop cursor.
  * @head:       the head for your list.
  *
  * This list-traversal primitive may safely run concurrently with
@@ -518,12 +548,13 @@ static inline void list_splice_init(struct list_head *list,
                 pos = pos->next)
 
 /**
- * list_for_each_safe_rcu       -       iterate over an rcu-protected list safe
- *                                      against removal of list entry
- * @pos:        the &struct list_head to use as a loop counter.
+ * list_for_each_safe_rcu
+ * @pos:        the &struct list_head to use as a loop cursor.
  * @n:          another &struct list_head to use as temporary storage
  * @head:       the head for your list.
  *
+ * Iterate over an rcu-protected list, safe against removal of list entry.
+ *
  * This list-traversal primitive may safely run concurrently with
  * the _rcu list-mutation primitives such as list_add_rcu()
  * as long as the traversal is guarded by rcu_read_lock().
@@ -535,7 +566,7 @@ static inline void list_splice_init(struct list_head *list,
 
 /**
  * list_for_each_entry_rcu      -       iterate over rcu list of given type
- * @pos:        the type * to use as a loop counter.
+ * @pos:        the type * to use as a loop cursor.
  * @head:       the head for your list.
  * @member:     the name of the list_struct within the struct.
  *
@@ -551,11 +582,12 @@ static inline void list_splice_init(struct list_head *list,
 
 
 /**
- * list_for_each_continue_rcu   -       iterate over an rcu-protected list
- *                      continuing after existing point.
- * @pos:        the &struct list_head to use as a loop counter.
+ * list_for_each_continue_rcu
+ * @pos:        the &struct list_head to use as a loop cursor.
  * @head:       the head for your list.
  *
+ * Iterate over an rcu-protected list, continuing after current point.
+ *
  * This list-traversal primitive may safely run concurrently with
  * the _rcu list-mutation primitives such as list_add_rcu()
  * as long as the traversal is guarded by rcu_read_lock().
@@ -681,11 +713,14 @@ static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h)
 
 
 /**
- * hlist_add_head_rcu - adds the specified element to the specified hlist,
- * while permitting racing traversals.
+ * hlist_add_head_rcu
  * @n: the element to add to the hash list.
  * @h: the list to add to.
  *
+ * Description:
+ * Adds the specified element to the specified hlist,
+ * while permitting racing traversals.
+ *
  * The caller must take whatever precautions are necessary
  * (such as holding appropriate locks) to avoid racing
  * with another list-mutation primitive, such as hlist_add_head_rcu()
@@ -730,11 +765,14 @@ static inline void hlist_add_after(struct hlist_node *n,
 }
 
 /**
- * hlist_add_before_rcu - adds the specified element to the specified hlist
- * before the specified node while permitting racing traversals.
+ * hlist_add_before_rcu
  * @n: the new element to add to the hash list.
  * @next: the existing element to add the new element before.
  *
+ * Description:
+ * Adds the specified element to the specified hlist
+ * before the specified node while permitting racing traversals.
+ *
  * The caller must take whatever precautions are necessary
  * (such as holding appropriate locks) to avoid racing
  * with another list-mutation primitive, such as hlist_add_head_rcu()
@@ -755,11 +793,14 @@ static inline void hlist_add_before_rcu(struct hlist_node *n,
 }
 
 /**
- * hlist_add_after_rcu - adds the specified element to the specified hlist
- * after the specified node while permitting racing traversals.
+ * hlist_add_after_rcu
  * @prev: the existing element to add the new element after.
  * @n: the new element to add to the hash list.
  *
+ * Description:
+ * Adds the specified element to the specified hlist
+ * after the specified node while permitting racing traversals.
+ *
  * The caller must take whatever precautions are necessary
  * (such as holding appropriate locks) to avoid racing
  * with another list-mutation primitive, such as hlist_add_head_rcu()
@@ -792,8 +833,8 @@ static inline void hlist_add_after_rcu(struct hlist_node *prev,
 
 /**
  * hlist_for_each_entry - iterate over list of given type
- * @tpos:       the type * to use as a loop counter.
- * @pos:        the &struct hlist_node to use as a loop counter.
+ * @tpos:       the type * to use as a loop cursor.
+ * @pos:        the &struct hlist_node to use as a loop cursor.
  * @head:       the head for your list.
  * @member:     the name of the hlist_node within the struct.
  */
@@ -804,9 +845,9 @@ static inline void hlist_add_after_rcu(struct hlist_node *prev,
              pos = pos->next)
 
 /**
- * hlist_for_each_entry_continue - iterate over a hlist continuing after existing point
- * @tpos:       the type * to use as a loop counter.
- * @pos:        the &struct hlist_node to use as a loop counter.
+ * hlist_for_each_entry_continue - iterate over a hlist continuing after current point
+ * @tpos:       the type * to use as a loop cursor.
+ * @pos:        the &struct hlist_node to use as a loop cursor.
  * @member:     the name of the hlist_node within the struct.
  */
 #define hlist_for_each_entry_continue(tpos, pos, member)                 \
@@ -816,9 +857,9 @@ static inline void hlist_add_after_rcu(struct hlist_node *prev,
              pos = pos->next)
 
 /**
- * hlist_for_each_entry_from - iterate over a hlist continuing from existing point
- * @tpos:       the type * to use as a loop counter.
- * @pos:        the &struct hlist_node to use as a loop counter.
+ * hlist_for_each_entry_from - iterate over a hlist continuing from current point
+ * @tpos:       the type * to use as a loop cursor.
+ * @pos:        the &struct hlist_node to use as a loop cursor.
  * @member:     the name of the hlist_node within the struct.
  */
 #define hlist_for_each_entry_from(tpos, pos, member)                     \
@@ -828,8 +869,8 @@ static inline void hlist_add_after_rcu(struct hlist_node *prev,
 
 /**
  * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry
- * @tpos:       the type * to use as a loop counter.
- * @pos:        the &struct hlist_node to use as a loop counter.
+ * @tpos:       the type * to use as a loop cursor.
+ * @pos:        the &struct hlist_node to use as a loop cursor.
  * @n:          another &struct hlist_node to use as temporary storage
  * @head:       the head for your list.
  * @member:     the name of the hlist_node within the struct.
@@ -842,8 +883,8 @@ static inline void hlist_add_after_rcu(struct hlist_node *prev,
 
 /**
  * hlist_for_each_entry_rcu - iterate over rcu list of given type
- * @tpos:       the type * to use as a loop counter.
- * @pos:        the &struct hlist_node to use as a loop counter.
+ * @tpos:       the type * to use as a loop cursor.
+ * @pos:        the &struct hlist_node to use as a loop cursor.
  * @head:       the head for your list.
  * @member:     the name of the hlist_node within the struct.
  *