* Copied from the Linux kernel source tree, version 2.6.13.
*
* Licensed under the GPL v2 as per the whole kernel source tree.
- *
*/
-/** \file list.h doubly linked list implementation */
+/** \file list.h Doubly linked list implementation. */
#include <stddef.h> /* offsetof */
-/** get the struct this entry is embedded in */
+/** Get the struct this entry is embedded in. */
#define container_of(ptr, type, member) ({ \
const typeof( ((type *)0)->member ) *__mptr = (ptr); \
(type *)( (char *)__mptr - offsetof(type,member) );})
-/**
- * Non-NULL pointers that will result in page faults under normal
- * circumstances, used to verify that nobody uses non-initialized list entries.
- * Used for poisoning the \a next pointer of struct list_head.
- */
-#define LIST_POISON1 ((void *) 0x00100100)
-/** Non-null pointer, used for poisoning the \a prev pointer of struct
- * list_head
- */
-#define LIST_POISON2 ((void *) 0x00200200)
-
-/** Simple doubly linked list implementation. */
+/** A list head is just a pair of pointers. */
struct list_head {
- /** pointer to the next list entry */
+ /** Pointer to the next list entry. */
struct list_head *next;
- /** pointer to the previous list entry */
+ /** Pointer to the previous list entry. */
struct list_head *prev;
};
/** Define an initialized list head. */
-#define INITIALIZED_LIST_HEAD(name) struct list_head name = { &(name), &(name) }
-
+#define INITIALIZED_LIST_HEAD(name) struct list_head name = {&(name), &(name)}
-/** must be called before using any other list functions */
+/** This must be called before using any other list functions. */
#define INIT_LIST_HEAD(ptr) do { \
(ptr)->next = (ptr); (ptr)->prev = (ptr); \
} while (0)
-
/*
- * Some of the internal functions ("__xxx") are useful when
- * manipulating whole lists rather than single entries, as
- * sometimes we already know the next/prev entries and we can
- * generate better code by using them directly rather than
+ * Some of the internal functions ("__xxx") are useful when manipulating whole
+ * lists rather than single entries, as sometimes we already know the next/prev
+ * entries and we can generate better code by using them directly rather than
* using the generic single-entry routines.
*/
-
/*
* Insert a new entry between two known consecutive entries.
*
- * This is only for internal list manipulation where we know
- * the prev/next entries already!
+ * \param new The new entry to add.
+ * \param prev The entry preceeding the new entry.
+ * \param next The entry following the new entry.
+ *
+ * This is only for internal list manipulations where we know the prev/next
+ * entries already.
*/
static inline void __list_add(struct list_head *new,
- struct list_head *prev,
- struct list_head *next)
+ struct list_head *prev, struct list_head *next)
{
next->prev = new;
new->next = next;
}
/**
- * add a new entry
+ * Insert a new entry after the specified head.
*
- * \param new new entry to be added
- * \param head list head to add it after
+ * \param new The new entry to add.
+ * \param head The list head to add it after.
*
- * Insert a new entry after the specified head.
* This is good for implementing stacks.
*/
static inline void para_list_add(struct list_head *new, struct list_head *head)
}
/**
- * add a new entry
+ * Insert a new entry before the specified head.
*
- * \param new new entry to be added
- * \param head list head to add it before
+ * \param new The new entry to add.
+ * \param head list head to add it before.
*
- * Insert a new entry before the specified head.
* This is useful for implementing queues.
*/
static inline void list_add_tail(struct list_head *new, struct list_head *head)
}
/*
- * Delete a list entry by making the prev/next entries
- * point to each other.
+ * Delete a list entry by making the prev/next entries point to each other.
*
- * This is only for internal list manipulation where we know
- * the prev/next entries already!
+ * This is only for internal list manipulation where we know the prev/next
+ * entries already.
*/
-static inline void __list_del(struct list_head * prev, struct list_head * next)
+static inline void __list_del(struct list_head *prev, struct list_head *next)
{
next->prev = prev;
prev->next = next;
}
+/*
+ * These non-NULL pointers result in page faults when dereferenced. This helps
+ * to catch bugs resulting from using deleted list heads.
+ */
+
+/** Used for poisoning the next pointer. */
+#define LIST_POISON1 ((void *)0x00100100)
+
+/** Used for poisoning the prev pointer. */
+#define LIST_POISON2 ((void *)0x00200200)
+
/**
- * Delete entry from list.
+ * Delete an entry from a list.
*
- * \param entry the element to delete from the list.
+ * \param entry The element to delete.
*
- * Note: list_empty on entry does not return true after this, the entry is
- * in an undefined state.
+ * The list entry is in an undefined state after this and \ref list_empty()
+ * does not return true.
*/
static inline void list_del(struct list_head *entry)
{
}
/**
- * delete from one list and add as another's head
+ * Delete an entry from one list and add it as another list's head.
*
- * \param list: the entry to move
- * \param head: the head that will precede our entry
+ * \param list The entry to move.
+ * \param head The head that will precede our entry.
*/
static inline void list_move(struct list_head *list, struct list_head *head)
{
}
/**
- * test whether a list is empty
+ * Test whether a list contains no entries.
*
- * \param head the list to test.
+ * \param head The list to test.
*/
static inline int list_empty(const struct list_head *head)
{
}
/**
- * get the struct for this entry
+ * Get the struct in which this entry is embedded in.
*
- * \param ptr the &struct list_head pointer.
- * \param type the type of the struct this is embedded in.
- * \param member the name of the list_struct within the struct.
+ * \param ptr The list head pointer.
+ * \param type The type of containing structure.
+ * \param member The name of the list head member within the structure.
*/
-#define list_entry(ptr, type, member) \
- container_of(ptr, type, member)
+#define list_entry(ptr, type, member) container_of(ptr, type, member)
/**
- * iterate over list of given type
+ * Iterate over a list.
*
- * \param pos the type * to use as a loop counter.
- * \param head the head for your list.
- * \param member the name of the list_struct within the struct.
+ * \param pos A list head pointer which serves as the iterator.
+ * \param head The head of the list.
+ * \param member The name of the list head member within the structure.
*/
#define list_for_each_entry(pos, head, member) \
for (pos = list_entry((head)->next, typeof(*pos), member); \
pos = list_entry(pos->member.next, typeof(*pos), member))
/**
- * iterate over list of given type safe against removal of list entry
+ * Iterate over list, safe against removal of list entry.
*
- * \param pos the type * to use as a loop counter.
- * \param n another type * to use as temporary storage
- * \param head the head for your list.
- * \param member the name of the list_struct within the struct.
+ * \param pos The iterator.
+ * \param n A list head pointer which is used as temporary storage.
+ * \param head The head of the list.
+ * \param member The name of the list head member within the structure.
*/
#define list_for_each_entry_safe(pos, n, head, member) \
for (pos = list_entry((head)->next, typeof(*pos), member), \
pos = n, n = list_entry(n->member.next, typeof(*n), member))
/**
- * Get the first element from a list
- * \param ptr the list head to take the element from.
+ * Get the first element of a list.
+ *
+ * \param ptr The list head to take the element from.
* \param type The type of the struct this is embedded in.
* \param member The name of the list_struct within the struct.
*
- * Note that list is expected to be not empty.
+ * Note that the list is expected to be non-empty.
*/
#define list_first_entry(ptr, type, member) \
- list_entry((ptr)->next, type, member)
+ list_entry((ptr)->next, type, member)
/**
* Test whether a list has just one entry.
{
return !list_empty(head) && (head->next == head->prev);
}
-
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