#ifndef _LINUX_LIST_H
#define _LINUX_LIST_H
-#ifdef __KERNEL__
-
#include <linux/stddef.h>
#include <linux/poison.h>
#include <linux/prefetch.h>
* 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
/**
}
/*
- * Insert a new entry between two known consecutive entries.
- *
- * This is only for internal list manipulation where we know
- * the prev/next entries already!
- */
-static inline void __list_add_rcu(struct list_head * new,
- struct list_head * prev, struct list_head * next)
-{
- new->next = next;
- new->prev = prev;
- smp_wmb();
- next->prev = new;
- prev->next = new;
-}
-
-/**
- * list_add_rcu - add a new entry to rcu-protected list
- * @new: new entry to be added
- * @head: list head to add it after
- *
- * Insert a new entry after the specified head.
- * This is good for implementing stacks.
- *
- * The caller must take whatever precautions are necessary
- * (such as holding appropriate locks) to avoid racing
- * with another list-mutation primitive, such as list_add_rcu()
- * or list_del_rcu(), running on this same list.
- * However, it is perfectly legal to run concurrently with
- * the _rcu list-traversal primitives, such as
- * list_for_each_entry_rcu().
- */
-static inline void list_add_rcu(struct list_head *new, struct list_head *head)
-{
- __list_add_rcu(new, head, head->next);
-}
-
-/**
- * list_add_tail_rcu - add a new entry to rcu-protected list
- * @new: new entry to be added
- * @head: list head to add it before
- *
- * Insert a new entry before the specified head.
- * This is useful for implementing queues.
- *
- * The caller must take whatever precautions are necessary
- * (such as holding appropriate locks) to avoid racing
- * with another list-mutation primitive, such as list_add_tail_rcu()
- * or list_del_rcu(), running on this same list.
- * However, it is perfectly legal to run concurrently with
- * the _rcu list-traversal primitives, such as
- * list_for_each_entry_rcu().
- */
-static inline void list_add_tail_rcu(struct list_head *new,
- struct list_head *head)
-{
- __list_add_rcu(new, head->prev, head);
-}
-
-/*
* Delete a list entry by making the prev/next entries
* point to each other.
*
/**
* list_del - deletes entry from list.
* @entry: the element to delete from the list.
- * Note: list_empty on entry does not return true after this, the entry is
+ * Note: list_empty() on entry does not return true after this, the entry is
* in an undefined state.
*/
#ifndef CONFIG_DEBUG_LIST
#endif
/**
- * list_del_rcu - deletes entry from list without re-initialization
- * @entry: the element to delete from the list.
- *
- * Note: list_empty on entry does not return true after this,
- * the entry is in an undefined state. It is useful for RCU based
- * lockfree traversal.
- *
- * In particular, it means that we can not poison the forward
- * pointers that may still be used for walking the list.
- *
- * The caller must take whatever precautions are necessary
- * (such as holding appropriate locks) to avoid racing
- * with another list-mutation primitive, such as list_del_rcu()
- * or list_add_rcu(), running on this same list.
- * However, it is perfectly legal to run concurrently with
- * the _rcu list-traversal primitives, such as
- * list_for_each_entry_rcu().
- *
- * Note that the caller is not permitted to immediately free
- * the newly deleted entry. Instead, either synchronize_rcu()
- * or call_rcu() must be used to defer freeing until an RCU
- * grace period has elapsed.
- */
-static inline void list_del_rcu(struct list_head *entry)
-{
- __list_del(entry->prev, entry->next);
- entry->prev = LIST_POISON2;
-}
-
-/**
* list_replace - replace old entry by new one
* @old : the element to be replaced
* @new : the new element to insert
- * Note: if 'old' was empty, it will be overwritten.
+ *
+ * If @old was empty, it will be overwritten.
*/
static inline void list_replace(struct list_head *old,
struct list_head *new)
}
/**
- * list_replace_rcu - replace old entry by new one
- * @old : the element to be replaced
- * @new : the new element to insert
- *
- * The @old entry will be replaced with the @new entry atomically.
- * Note: @old should not be empty.
- */
-static inline void list_replace_rcu(struct list_head *old,
- struct list_head *new)
-{
- new->next = old->next;
- new->prev = old->prev;
- smp_wmb();
- new->next->prev = new;
- new->prev->next = new;
- old->prev = LIST_POISON2;
-}
-
-/**
* list_del_init - deletes entry from list and reinitialize it.
* @entry: the element to delete from the list.
*/
*/
static inline void list_move(struct list_head *list, struct list_head *head)
{
- __list_del(list->prev, list->next);
- list_add(list, head);
+ __list_del(list->prev, list->next);
+ list_add(list, head);
}
/**
static inline void list_move_tail(struct list_head *list,
struct list_head *head)
{
- __list_del(list->prev, list->next);
- list_add_tail(list, head);
+ __list_del(list->prev, list->next);
+ list_add_tail(list, head);
}
/**
return (next == head) && (next == head->prev);
}
-static inline void __list_splice(struct list_head *list,
- struct list_head *head)
+/**
+ * list_is_singular - tests whether a list has just one entry.
+ * @head: the list to test.
+ */
+static inline int list_is_singular(const struct list_head *head)
+{
+ return !list_empty(head) && (head->next == head->prev);
+}
+
+static inline void __list_cut_position(struct list_head *list,
+ struct list_head *head, struct list_head *entry)
+{
+ struct list_head *new_first = entry->next;
+ list->next = head->next;
+ list->next->prev = list;
+ list->prev = entry;
+ entry->next = list;
+ head->next = new_first;
+ new_first->prev = head;
+}
+
+/**
+ * list_cut_position - cut a list into two
+ * @list: a new list to add all removed entries
+ * @head: a list with entries
+ * @entry: an entry within head, could be the head itself
+ * and if so we won't cut the list
+ *
+ * This helper moves the initial part of @head, up to and
+ * including @entry, from @head to @list. You should
+ * pass on @entry an element you know is on @head. @list
+ * should be an empty list or a list you do not care about
+ * losing its data.
+ *
+ */
+static inline void list_cut_position(struct list_head *list,
+ struct list_head *head, struct list_head *entry)
+{
+ if (list_empty(head))
+ return;
+ if (list_is_singular(head) &&
+ (head->next != entry && head != entry))
+ return;
+ if (entry == head)
+ INIT_LIST_HEAD(list);
+ else
+ __list_cut_position(list, head, entry);
+}
+
+static inline void __list_splice(const struct list_head *list,
+ struct list_head *prev,
+ struct list_head *next)
{
struct list_head *first = list->next;
struct list_head *last = list->prev;
- struct list_head *at = head->next;
- first->prev = head;
- head->next = first;
+ first->prev = prev;
+ prev->next = first;
- last->next = at;
- at->prev = last;
+ last->next = next;
+ next->prev = last;
}
/**
- * list_splice - join two lists
+ * list_splice - join two lists, this is designed for stacks
* @list: the new list to add.
* @head: the place to add it in the first list.
*/
-static inline void list_splice(struct list_head *list, struct list_head *head)
+static inline void list_splice(const struct list_head *list,
+ struct list_head *head)
{
if (!list_empty(list))
- __list_splice(list, head);
+ __list_splice(list, head, head->next);
+}
+
+/**
+ * list_splice_tail - join two lists, each list being a queue
+ * @list: the new list to add.
+ * @head: the place to add it in the first list.
+ */
+static inline void list_splice_tail(struct list_head *list,
+ struct list_head *head)
+{
+ if (!list_empty(list))
+ __list_splice(list, head->prev, head);
}
/**
struct list_head *head)
{
if (!list_empty(list)) {
- __list_splice(list, head);
+ __list_splice(list, head, head->next);
INIT_LIST_HEAD(list);
}
}
/**
- * list_splice_init_rcu - splice an RCU-protected list into an existing list.
- * @list: the RCU-protected list to splice
- * @head: the place in the list to splice the first list into
- * @sync: function to sync: synchronize_rcu(), synchronize_sched(), ...
- *
- * @head can be RCU-read traversed concurrently with this function.
- *
- * Note that this function blocks.
+ * list_splice_tail_init - join two lists and reinitialise the emptied list
+ * @list: the new list to add.
+ * @head: the place to add it in the first list.
*
- * Important note: the caller must take whatever action is necessary to
- * prevent any other updates to @head. In principle, it is possible
- * to modify the list as soon as sync() begins execution.
- * If this sort of thing becomes necessary, an alternative version
- * based on call_rcu() could be created. But only if -really-
- * needed -- there is no shortage of RCU API members.
+ * Each of the lists is a queue.
+ * The list at @list is reinitialised
*/
-static inline void list_splice_init_rcu(struct list_head *list,
- struct list_head *head,
- void (*sync)(void))
+static inline void list_splice_tail_init(struct list_head *list,
+ struct list_head *head)
{
- struct list_head *first = list->next;
- struct list_head *last = list->prev;
- struct list_head *at = head->next;
-
- if (list_empty(head))
- return;
-
- /* "first" and "last" tracking list, so initialize it. */
-
- INIT_LIST_HEAD(list);
-
- /*
- * At this point, the list body still points to the source list.
- * Wait for any readers to finish using the list before splicing
- * the list body into the new list. Any new readers will see
- * an empty list.
- */
-
- sync();
-
- /*
- * Readers are finished with the source list, so perform splice.
- * The order is important if the new list is global and accessible
- * to concurrent RCU readers. Note that RCU readers are not
- * permitted to traverse the prev pointers without excluding
- * this function.
- */
-
- last->next = at;
- smp_wmb();
- head->next = first;
- first->prev = head;
- at->prev = last;
+ if (!list_empty(list)) {
+ __list_splice(list, head->prev, head);
+ INIT_LIST_HEAD(list);
+ }
}
/**
container_of(ptr, type, member)
/**
+ * list_first_entry - get the first element from a list
+ * @ptr: the list head to take the element from.
+ * @type: the type of the struct this is embedded in.
+ * @member: the name of the list_struct within the struct.
+ *
+ * Note, that list is expected to be not empty.
+ */
+#define list_first_entry(ptr, type, member) \
+ list_entry((ptr)->next, type, member)
+
+/**
* list_for_each - iterate over a list
* @pos: the &struct list_head to use as a loop cursor.
* @head: the head for your list.
pos = n, n = pos->next)
/**
+ * list_for_each_prev_safe - iterate over a list backwards 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.
+ */
+#define list_for_each_prev_safe(pos, n, head) \
+ for (pos = (head)->prev, n = pos->prev; \
+ prefetch(pos->prev), pos != (head); \
+ pos = n, n = pos->prev)
+
+/**
* list_for_each_entry - iterate over list of given type
* @pos: the type * to use as a loop cursor.
* @head: the head for your list.
pos = list_entry(pos->member.prev, typeof(*pos), member))
/**
- * list_prepare_entry - prepare a pos entry for use 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.
+ * 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))
pos = list_entry(pos->member.next, typeof(*pos), member))
/**
+ * list_for_each_entry_continue_reverse - iterate backwards from the given 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.
+ *
+ * Start to iterate over list of given type backwards, continuing after
+ * the current position.
+ */
+#define list_for_each_entry_continue_reverse(pos, head, member) \
+ for (pos = list_entry(pos->member.prev, typeof(*pos), member); \
+ prefetch(pos->member.prev), &pos->member != (head); \
+ pos = list_entry(pos->member.prev, typeof(*pos), member))
+
+/**
* 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.
&pos->member != (head); \
pos = n, n = list_entry(n->member.prev, typeof(*n), member))
-/**
- * list_for_each_rcu - iterate over an rcu-protected list
- * @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
- * the _rcu list-mutation primitives such as list_add_rcu()
- * as long as the traversal is guarded by rcu_read_lock().
- */
-#define list_for_each_rcu(pos, head) \
- for (pos = (head)->next; \
- prefetch(rcu_dereference(pos)->next), pos != (head); \
- pos = pos->next)
-
-#define __list_for_each_rcu(pos, head) \
- for (pos = (head)->next; \
- rcu_dereference(pos) != (head); \
- pos = pos->next)
-
-/**
- * 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().
- */
-#define list_for_each_safe_rcu(pos, n, head) \
- for (pos = (head)->next; \
- n = rcu_dereference(pos)->next, pos != (head); \
- pos = n)
-
-/**
- * list_for_each_entry_rcu - iterate over rcu 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.
- *
- * 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().
- */
-#define list_for_each_entry_rcu(pos, head, member) \
- for (pos = list_entry((head)->next, typeof(*pos), member); \
- prefetch(rcu_dereference(pos)->member.next), \
- &pos->member != (head); \
- pos = list_entry(pos->member.next, typeof(*pos), member))
-
-
-/**
- * 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().
- */
-#define list_for_each_continue_rcu(pos, head) \
- for ((pos) = (pos)->next; \
- prefetch(rcu_dereference((pos))->next), (pos) != (head); \
- (pos) = (pos)->next)
-
/*
* Double linked lists with a single pointer list head.
* Mostly useful for hash tables where the two pointer list head is
n->pprev = LIST_POISON2;
}
-/**
- * hlist_del_rcu - deletes entry from hash list without re-initialization
- * @n: the element to delete from the hash list.
- *
- * Note: list_unhashed() on entry does not return true after this,
- * the entry is in an undefined state. It is useful for RCU based
- * lockfree traversal.
- *
- * In particular, it means that we can not poison the forward
- * pointers that may still be used for walking the hash list.
- *
- * 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()
- * or hlist_del_rcu(), running on this same list.
- * However, it is perfectly legal to run concurrently with
- * the _rcu list-traversal primitives, such as
- * hlist_for_each_entry().
- */
-static inline void hlist_del_rcu(struct hlist_node *n)
-{
- __hlist_del(n);
- n->pprev = LIST_POISON2;
-}
-
static inline void hlist_del_init(struct hlist_node *n)
{
if (!hlist_unhashed(n)) {
}
}
-/**
- * hlist_replace_rcu - replace old entry by new one
- * @old : the element to be replaced
- * @new : the new element to insert
- *
- * The @old entry will be replaced with the @new entry atomically.
- */
-static inline void hlist_replace_rcu(struct hlist_node *old,
- struct hlist_node *new)
-{
- struct hlist_node *next = old->next;
-
- new->next = next;
- new->pprev = old->pprev;
- smp_wmb();
- if (next)
- new->next->pprev = &new->next;
- *new->pprev = new;
- old->pprev = LIST_POISON2;
-}
-
static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h)
{
struct hlist_node *first = h->first;
n->pprev = &h->first;
}
-
-/**
- * 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()
- * or hlist_del_rcu(), running on this same list.
- * However, it is perfectly legal to run concurrently with
- * the _rcu list-traversal primitives, such as
- * hlist_for_each_entry_rcu(), used to prevent memory-consistency
- * problems on Alpha CPUs. Regardless of the type of CPU, the
- * list-traversal primitive must be guarded by rcu_read_lock().
- */
-static inline void hlist_add_head_rcu(struct hlist_node *n,
- struct hlist_head *h)
-{
- struct hlist_node *first = h->first;
- n->next = first;
- n->pprev = &h->first;
- smp_wmb();
- if (first)
- first->pprev = &n->next;
- h->first = n;
-}
-
/* next must be != NULL */
static inline void hlist_add_before(struct hlist_node *n,
struct hlist_node *next)
next->next->pprev = &next->next;
}
-/**
- * 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()
- * or hlist_del_rcu(), running on this same list.
- * However, it is perfectly legal to run concurrently with
- * the _rcu list-traversal primitives, such as
- * hlist_for_each_entry_rcu(), used to prevent memory-consistency
- * problems on Alpha CPUs.
- */
-static inline void hlist_add_before_rcu(struct hlist_node *n,
- struct hlist_node *next)
+/*
+ * Move a list from one list head to another. Fixup the pprev
+ * reference of the first entry if it exists.
+ */
+static inline void hlist_move_list(struct hlist_head *old,
+ struct hlist_head *new)
{
- n->pprev = next->pprev;
- n->next = next;
- smp_wmb();
- next->pprev = &n->next;
- *(n->pprev) = n;
-}
-
-/**
- * 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()
- * or hlist_del_rcu(), running on this same list.
- * However, it is perfectly legal to run concurrently with
- * the _rcu list-traversal primitives, such as
- * hlist_for_each_entry_rcu(), used to prevent memory-consistency
- * problems on Alpha CPUs.
- */
-static inline void hlist_add_after_rcu(struct hlist_node *prev,
- struct hlist_node *n)
-{
- n->next = prev->next;
- n->pprev = &prev->next;
- smp_wmb();
- prev->next = n;
- if (n->next)
- n->next->pprev = &n->next;
+ new->first = old->first;
+ if (new->first)
+ new->first->pprev = &new->first;
+ old->first = NULL;
}
#define hlist_entry(ptr, type, member) container_of(ptr,type,member)
({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
pos = n)
-/**
- * hlist_for_each_entry_rcu - iterate over rcu list of given type
- * @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.
- *
- * This list-traversal primitive may safely run concurrently with
- * the _rcu list-mutation primitives such as hlist_add_head_rcu()
- * as long as the traversal is guarded by rcu_read_lock().
- */
-#define hlist_for_each_entry_rcu(tpos, pos, head, member) \
- for (pos = (head)->first; \
- rcu_dereference(pos) && ({ prefetch(pos->next); 1;}) && \
- ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
- pos = pos->next)
-
-#else
-#warning "don't include kernel headers in userspace"
-#endif /* __KERNEL__ */
#endif
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff