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- /* SPDX-License-Identifier: GPL-2.0 */
- #ifndef _LINUX_LIST_H
- #define _LINUX_LIST_H
- #include <linux/container_of.h>
- #include <linux/types.h>
- #include <linux/stddef.h>
- #include <linux/poison.h>
- #include <linux/const.h>
- #include <asm/barrier.h>
- /*
- * Circular doubly linked list implementation.
- *
- * 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.
- */
- #define LIST_HEAD_INIT(name) { &(name), &(name) }
- #define LIST_HEAD(name) \
- struct list_head name = LIST_HEAD_INIT(name)
- /**
- * INIT_LIST_HEAD - Initialize a list_head structure
- * @list: list_head structure to be initialized.
- *
- * Initializes the list_head to point to itself. If it is a list header,
- * the result is an empty list.
- */
- static inline void INIT_LIST_HEAD(struct list_head *list)
- {
- WRITE_ONCE(list->next, list);
- WRITE_ONCE(list->prev, list);
- }
- #ifdef CONFIG_DEBUG_LIST
- extern bool __list_add_valid(struct list_head *new,
- struct list_head *prev,
- struct list_head *next);
- extern bool __list_del_entry_valid(struct list_head *entry);
- #else
- static inline bool __list_add_valid(struct list_head *new,
- struct list_head *prev,
- struct list_head *next)
- {
- return true;
- }
- static inline bool __list_del_entry_valid(struct list_head *entry)
- {
- return true;
- }
- #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(struct list_head *new,
- struct list_head *prev,
- struct list_head *next)
- {
- if (!__list_add_valid(new, prev, next))
- return;
- next->prev = new;
- new->next = next;
- new->prev = prev;
- WRITE_ONCE(prev->next, new);
- }
- /**
- * list_add - add a new entry
- * @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.
- */
- static inline void list_add(struct list_head *new, struct list_head *head)
- {
- __list_add(new, head, head->next);
- }
- /**
- * list_add_tail - add a new entry
- * @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.
- */
- static inline void list_add_tail(struct list_head *new, struct list_head *head)
- {
- __list_add(new, head->prev, head);
- }
- /*
- * 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!
- */
- static inline void __list_del(struct list_head * prev, struct list_head * next)
- {
- next->prev = prev;
- WRITE_ONCE(prev->next, next);
- }
- /*
- * Delete a list entry and clear the 'prev' pointer.
- *
- * This is a special-purpose list clearing method used in the networking code
- * for lists allocated as per-cpu, where we don't want to incur the extra
- * WRITE_ONCE() overhead of a regular list_del_init(). The code that uses this
- * needs to check the node 'prev' pointer instead of calling list_empty().
- */
- static inline void __list_del_clearprev(struct list_head *entry)
- {
- __list_del(entry->prev, entry->next);
- entry->prev = NULL;
- }
- static inline void __list_del_entry(struct list_head *entry)
- {
- if (!__list_del_entry_valid(entry))
- return;
- __list_del(entry->prev, entry->next);
- }
- /**
- * 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
- * in an undefined state.
- */
- static inline void list_del(struct list_head *entry)
- {
- __list_del_entry(entry);
- entry->next = LIST_POISON1;
- entry->prev = LIST_POISON2;
- }
- /**
- * list_replace - replace old entry by new one
- * @old : the element to be replaced
- * @new : the new element to insert
- *
- * If @old was empty, it will be overwritten.
- */
- static inline void list_replace(struct list_head *old,
- struct list_head *new)
- {
- new->next = old->next;
- new->next->prev = new;
- new->prev = old->prev;
- new->prev->next = new;
- }
- /**
- * list_replace_init - replace old entry by new one and initialize the old one
- * @old : the element to be replaced
- * @new : the new element to insert
- *
- * If @old was empty, it will be overwritten.
- */
- static inline void list_replace_init(struct list_head *old,
- struct list_head *new)
- {
- list_replace(old, new);
- INIT_LIST_HEAD(old);
- }
- /**
- * list_swap - replace entry1 with entry2 and re-add entry1 at entry2's position
- * @entry1: the location to place entry2
- * @entry2: the location to place entry1
- */
- static inline void list_swap(struct list_head *entry1,
- struct list_head *entry2)
- {
- struct list_head *pos = entry2->prev;
- list_del(entry2);
- list_replace(entry1, entry2);
- if (pos == entry1)
- pos = entry2;
- list_add(entry1, pos);
- }
- /**
- * list_del_init - deletes entry from list and reinitialize it.
- * @entry: the element to delete from the list.
- */
- static inline void list_del_init(struct list_head *entry)
- {
- __list_del_entry(entry);
- INIT_LIST_HEAD(entry);
- }
- /**
- * list_move - delete from one list and add as another's head
- * @list: the entry to move
- * @head: the head that will precede our entry
- */
- static inline void list_move(struct list_head *list, struct list_head *head)
- {
- __list_del_entry(list);
- list_add(list, head);
- }
- /**
- * list_move_tail - delete from one list and add as another's tail
- * @list: the entry to move
- * @head: the head that will follow our entry
- */
- static inline void list_move_tail(struct list_head *list,
- struct list_head *head)
- {
- __list_del_entry(list);
- list_add_tail(list, head);
- }
- /**
- * list_bulk_move_tail - move a subsection of a list to its tail
- * @head: the head that will follow our entry
- * @first: first entry to move
- * @last: last entry to move, can be the same as first
- *
- * Move all entries between @first and including @last before @head.
- * All three entries must belong to the same linked list.
- */
- static inline void list_bulk_move_tail(struct list_head *head,
- struct list_head *first,
- struct list_head *last)
- {
- first->prev->next = last->next;
- last->next->prev = first->prev;
- head->prev->next = first;
- first->prev = head->prev;
- last->next = head;
- head->prev = last;
- }
- /**
- * list_is_first -- tests whether @list is the first entry in list @head
- * @list: the entry to test
- * @head: the head of the list
- */
- static inline int list_is_first(const struct list_head *list, const struct list_head *head)
- {
- return list->prev == head;
- }
- /**
- * 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_is_head - tests whether @list is the list @head
- * @list: the entry to test
- * @head: the head of the list
- */
- static inline int list_is_head(const struct list_head *list, const struct list_head *head)
- {
- return list == head;
- }
- /**
- * list_empty - tests whether a list is empty
- * @head: the list to test.
- */
- static inline int list_empty(const struct list_head *head)
- {
- return READ_ONCE(head->next) == head;
- }
- /**
- * list_del_init_careful - deletes entry from list and reinitialize it.
- * @entry: the element to delete from the list.
- *
- * This is the same as list_del_init(), except designed to be used
- * together with list_empty_careful() in a way to guarantee ordering
- * of other memory operations.
- *
- * Any memory operations done before a list_del_init_careful() are
- * guaranteed to be visible after a list_empty_careful() test.
- */
- static inline void list_del_init_careful(struct list_head *entry)
- {
- __list_del_entry(entry);
- WRITE_ONCE(entry->prev, entry);
- smp_store_release(&entry->next, entry);
- }
- /**
- * 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.
- */
- static inline int list_empty_careful(const struct list_head *head)
- {
- struct list_head *next = smp_load_acquire(&head->next);
- return list_is_head(next, head) && (next == READ_ONCE(head->prev));
- }
- /**
- * list_rotate_left - rotate the list to the left
- * @head: the head of the list
- */
- static inline void list_rotate_left(struct list_head *head)
- {
- struct list_head *first;
- if (!list_empty(head)) {
- first = head->next;
- list_move_tail(first, head);
- }
- }
- /**
- * list_rotate_to_front() - Rotate list to specific item.
- * @list: The desired new front of the list.
- * @head: The head of the list.
- *
- * Rotates list so that @list becomes the new front of the list.
- */
- static inline void list_rotate_to_front(struct list_head *list,
- struct list_head *head)
- {
- /*
- * Deletes the list head from the list denoted by @head and
- * places it as the tail of @list, this effectively rotates the
- * list so that @list is at the front.
- */
- list_move_tail(head, list);
- }
- /**
- * 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) && !list_is_head(entry, head) && (entry != head->next))
- return;
- if (list_is_head(entry, head))
- INIT_LIST_HEAD(list);
- else
- __list_cut_position(list, head, entry);
- }
- /**
- * list_cut_before - cut a list into two, before given entry
- * @list: a new list to add all removed entries
- * @head: a list with entries
- * @entry: an entry within head, could be the head itself
- *
- * This helper moves the initial part of @head, up to but
- * excluding @entry, from @head to @list. You should pass
- * in @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.
- * If @entry == @head, all entries on @head are moved to
- * @list.
- */
- static inline void list_cut_before(struct list_head *list,
- struct list_head *head,
- struct list_head *entry)
- {
- if (head->next == entry) {
- INIT_LIST_HEAD(list);
- return;
- }
- list->next = head->next;
- list->next->prev = list;
- list->prev = entry->prev;
- list->prev->next = list;
- head->next = entry;
- entry->prev = head;
- }
- 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;
- first->prev = prev;
- prev->next = first;
- last->next = next;
- next->prev = last;
- }
- /**
- * 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(const struct list_head *list,
- struct list_head *head)
- {
- if (!list_empty(list))
- __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);
- }
- /**
- * list_splice_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.
- *
- * The list at @list is reinitialised
- */
- static inline void list_splice_init(struct list_head *list,
- struct list_head *head)
- {
- if (!list_empty(list)) {
- __list_splice(list, head, head->next);
- INIT_LIST_HEAD(list);
- }
- }
- /**
- * 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.
- *
- * Each of the lists is a queue.
- * The list at @list is reinitialised
- */
- static inline void list_splice_tail_init(struct list_head *list,
- struct list_head *head)
- {
- if (!list_empty(list)) {
- __list_splice(list, head->prev, head);
- INIT_LIST_HEAD(list);
- }
- }
- /**
- * list_entry - get the struct for this entry
- * @ptr: the &struct list_head pointer.
- * @type: the type of the struct this is embedded in.
- * @member: the name of the list_head within the struct.
- */
- #define list_entry(ptr, type, member) \
- 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_head 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_last_entry - get the last 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_head within the struct.
- *
- * Note, that list is expected to be not empty.
- */
- #define list_last_entry(ptr, type, member) \
- list_entry((ptr)->prev, type, member)
- /**
- * list_first_entry_or_null - 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_head within the struct.
- *
- * Note that if the list is empty, it returns NULL.
- */
- #define list_first_entry_or_null(ptr, type, member) ({ \
- struct list_head *head__ = (ptr); \
- struct list_head *pos__ = READ_ONCE(head__->next); \
- pos__ != head__ ? list_entry(pos__, type, member) : NULL; \
- })
- /**
- * list_next_entry - get the next element in list
- * @pos: the type * to cursor
- * @member: the name of the list_head within the struct.
- */
- #define list_next_entry(pos, member) \
- list_entry((pos)->member.next, typeof(*(pos)), member)
- /**
- * list_next_entry_circular - get the next element in list
- * @pos: the type * to cursor.
- * @head: the list head to take the element from.
- * @member: the name of the list_head within the struct.
- *
- * Wraparound if pos is the last element (return the first element).
- * Note, that list is expected to be not empty.
- */
- #define list_next_entry_circular(pos, head, member) \
- (list_is_last(&(pos)->member, head) ? \
- list_first_entry(head, typeof(*(pos)), member) : list_next_entry(pos, member))
- /**
- * list_prev_entry - get the prev element in list
- * @pos: the type * to cursor
- * @member: the name of the list_head within the struct.
- */
- #define list_prev_entry(pos, member) \
- list_entry((pos)->member.prev, typeof(*(pos)), member)
- /**
- * list_prev_entry_circular - get the prev element in list
- * @pos: the type * to cursor.
- * @head: the list head to take the element from.
- * @member: the name of the list_head within the struct.
- *
- * Wraparound if pos is the first element (return the last element).
- * Note, that list is expected to be not empty.
- */
- #define list_prev_entry_circular(pos, head, member) \
- (list_is_first(&(pos)->member, head) ? \
- list_last_entry(head, typeof(*(pos)), member) : list_prev_entry(pos, 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.
- */
- #define list_for_each(pos, head) \
- for (pos = (head)->next; !list_is_head(pos, (head)); pos = pos->next)
- /**
- * list_for_each_rcu - Iterate over a list in an RCU-safe fashion
- * @pos: the &struct list_head to use as a loop cursor.
- * @head: the head for your list.
- */
- #define list_for_each_rcu(pos, head) \
- for (pos = rcu_dereference((head)->next); \
- !list_is_head(pos, (head)); \
- pos = rcu_dereference(pos->next))
- /**
- * list_for_each_continue - continue iteration over a list
- * @pos: the &struct list_head to use as a loop cursor.
- * @head: the head for your list.
- *
- * Continue to iterate over a list, continuing after the current position.
- */
- #define list_for_each_continue(pos, head) \
- for (pos = pos->next; !list_is_head(pos, (head)); pos = pos->next)
- /**
- * list_for_each_prev - iterate over a list backwards
- * @pos: the &struct list_head to use as a loop cursor.
- * @head: the head for your list.
- */
- #define list_for_each_prev(pos, head) \
- for (pos = (head)->prev; !list_is_head(pos, (head)); 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 cursor.
- * @n: another &struct list_head to use as temporary storage
- * @head: the head for your list.
- */
- #define list_for_each_safe(pos, n, head) \
- for (pos = (head)->next, n = pos->next; \
- !list_is_head(pos, (head)); \
- 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; \
- !list_is_head(pos, (head)); \
- pos = n, n = pos->prev)
- /**
- * list_entry_is_head - test if the entry points to the head of the list
- * @pos: the type * to cursor
- * @head: the head for your list.
- * @member: the name of the list_head within the struct.
- */
- #define list_entry_is_head(pos, head, member) \
- (&pos->member == (head))
- /**
- * 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.
- * @member: the name of the list_head within the struct.
- */
- #define list_for_each_entry(pos, head, member) \
- for (pos = list_first_entry(head, typeof(*pos), member); \
- !list_entry_is_head(pos, head, member); \
- pos = list_next_entry(pos, member))
- /**
- * list_for_each_entry_reverse - iterate backwards 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_head within the struct.
- */
- #define list_for_each_entry_reverse(pos, head, member) \
- for (pos = list_last_entry(head, typeof(*pos), member); \
- !list_entry_is_head(pos, head, member); \
- pos = list_prev_entry(pos, member))
- /**
- * 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_head 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 - 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_head 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_next_entry(pos, member); \
- !list_entry_is_head(pos, head, member); \
- pos = list_next_entry(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_head 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_prev_entry(pos, member); \
- !list_entry_is_head(pos, head, member); \
- pos = list_prev_entry(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.
- * @member: the name of the list_head within the struct.
- *
- * Iterate over list of given type, continuing from current position.
- */
- #define list_for_each_entry_from(pos, head, member) \
- for (; !list_entry_is_head(pos, head, member); \
- pos = list_next_entry(pos, member))
- /**
- * list_for_each_entry_from_reverse - iterate backwards 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_head within the struct.
- *
- * Iterate backwards over list of given type, continuing from current position.
- */
- #define list_for_each_entry_from_reverse(pos, head, member) \
- for (; !list_entry_is_head(pos, head, member); \
- pos = list_prev_entry(pos, member))
- /**
- * 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 cursor.
- * @n: another type * to use as temporary storage
- * @head: the head for your list.
- * @member: the name of the list_head within the struct.
- */
- #define list_for_each_entry_safe(pos, n, head, member) \
- for (pos = list_first_entry(head, typeof(*pos), member), \
- n = list_next_entry(pos, member); \
- !list_entry_is_head(pos, head, member); \
- pos = n, n = list_next_entry(n, member))
- /**
- * list_for_each_entry_safe_continue - continue list iteration safe against removal
- * @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_head 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_next_entry(pos, member), \
- n = list_next_entry(pos, member); \
- !list_entry_is_head(pos, head, member); \
- pos = n, n = list_next_entry(n, member))
- /**
- * list_for_each_entry_safe_from - iterate over list from current point safe against removal
- * @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_head 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_next_entry(pos, member); \
- !list_entry_is_head(pos, head, member); \
- pos = n, n = list_next_entry(n, member))
- /**
- * list_for_each_entry_safe_reverse - iterate backwards over list safe against removal
- * @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_head 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_last_entry(head, typeof(*pos), member), \
- n = list_prev_entry(pos, member); \
- !list_entry_is_head(pos, head, member); \
- pos = n, n = list_prev_entry(n, member))
- /**
- * list_safe_reset_next - reset a stale list_for_each_entry_safe loop
- * @pos: the loop cursor used in the list_for_each_entry_safe loop
- * @n: temporary storage used in list_for_each_entry_safe
- * @member: the name of the list_head within the struct.
- *
- * list_safe_reset_next is not safe to use in general if the list may be
- * modified concurrently (eg. the lock is dropped in the loop body). An
- * exception to this is if the cursor element (pos) is pinned in the list,
- * and list_safe_reset_next is called after re-taking the lock and before
- * completing the current iteration of the loop body.
- */
- #define list_safe_reset_next(pos, n, member) \
- n = list_next_entry(pos, member)
- /*
- * Double linked lists with a single pointer list head.
- * Mostly useful for hash tables where the two pointer list head is
- * too wasteful.
- * You lose the ability to access the tail in O(1).
- */
- #define HLIST_HEAD_INIT { .first = NULL }
- #define HLIST_HEAD(name) struct hlist_head name = { .first = NULL }
- #define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL)
- static inline void INIT_HLIST_NODE(struct hlist_node *h)
- {
- h->next = NULL;
- h->pprev = NULL;
- }
- /**
- * hlist_unhashed - Has node been removed from list and reinitialized?
- * @h: Node to be checked
- *
- * Not that not all removal functions will leave a node in unhashed
- * state. For example, hlist_nulls_del_init_rcu() does leave the
- * node in unhashed state, but hlist_nulls_del() does not.
- */
- static inline int hlist_unhashed(const struct hlist_node *h)
- {
- return !h->pprev;
- }
- /**
- * hlist_unhashed_lockless - Version of hlist_unhashed for lockless use
- * @h: Node to be checked
- *
- * This variant of hlist_unhashed() must be used in lockless contexts
- * to avoid potential load-tearing. The READ_ONCE() is paired with the
- * various WRITE_ONCE() in hlist helpers that are defined below.
- */
- static inline int hlist_unhashed_lockless(const struct hlist_node *h)
- {
- return !READ_ONCE(h->pprev);
- }
- /**
- * hlist_empty - Is the specified hlist_head structure an empty hlist?
- * @h: Structure to check.
- */
- static inline int hlist_empty(const struct hlist_head *h)
- {
- return !READ_ONCE(h->first);
- }
- static inline void __hlist_del(struct hlist_node *n)
- {
- struct hlist_node *next = n->next;
- struct hlist_node **pprev = n->pprev;
- WRITE_ONCE(*pprev, next);
- if (next)
- WRITE_ONCE(next->pprev, pprev);
- }
- /**
- * hlist_del - Delete the specified hlist_node from its list
- * @n: Node to delete.
- *
- * Note that this function leaves the node in hashed state. Use
- * hlist_del_init() or similar instead to unhash @n.
- */
- static inline void hlist_del(struct hlist_node *n)
- {
- __hlist_del(n);
- n->next = LIST_POISON1;
- n->pprev = LIST_POISON2;
- }
- /**
- * hlist_del_init - Delete the specified hlist_node from its list and initialize
- * @n: Node to delete.
- *
- * Note that this function leaves the node in unhashed state.
- */
- static inline void hlist_del_init(struct hlist_node *n)
- {
- if (!hlist_unhashed(n)) {
- __hlist_del(n);
- INIT_HLIST_NODE(n);
- }
- }
- /**
- * hlist_add_head - add a new entry at the beginning of the hlist
- * @n: new entry to be added
- * @h: hlist head to add it after
- *
- * Insert a new entry after the specified head.
- * This is good for implementing stacks.
- */
- static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h)
- {
- struct hlist_node *first = h->first;
- WRITE_ONCE(n->next, first);
- if (first)
- WRITE_ONCE(first->pprev, &n->next);
- WRITE_ONCE(h->first, n);
- WRITE_ONCE(n->pprev, &h->first);
- }
- /**
- * hlist_add_before - add a new entry before the one specified
- * @n: new entry to be added
- * @next: hlist node to add it before, which must be non-NULL
- */
- static inline void hlist_add_before(struct hlist_node *n,
- struct hlist_node *next)
- {
- WRITE_ONCE(n->pprev, next->pprev);
- WRITE_ONCE(n->next, next);
- WRITE_ONCE(next->pprev, &n->next);
- WRITE_ONCE(*(n->pprev), n);
- }
- /**
- * hlist_add_behind - add a new entry after the one specified
- * @n: new entry to be added
- * @prev: hlist node to add it after, which must be non-NULL
- */
- static inline void hlist_add_behind(struct hlist_node *n,
- struct hlist_node *prev)
- {
- WRITE_ONCE(n->next, prev->next);
- WRITE_ONCE(prev->next, n);
- WRITE_ONCE(n->pprev, &prev->next);
- if (n->next)
- WRITE_ONCE(n->next->pprev, &n->next);
- }
- /**
- * hlist_add_fake - create a fake hlist consisting of a single headless node
- * @n: Node to make a fake list out of
- *
- * This makes @n appear to be its own predecessor on a headless hlist.
- * The point of this is to allow things like hlist_del() to work correctly
- * in cases where there is no list.
- */
- static inline void hlist_add_fake(struct hlist_node *n)
- {
- n->pprev = &n->next;
- }
- /**
- * hlist_fake: Is this node a fake hlist?
- * @h: Node to check for being a self-referential fake hlist.
- */
- static inline bool hlist_fake(struct hlist_node *h)
- {
- return h->pprev == &h->next;
- }
- /**
- * hlist_is_singular_node - is node the only element of the specified hlist?
- * @n: Node to check for singularity.
- * @h: Header for potentially singular list.
- *
- * Check whether the node is the only node of the head without
- * accessing head, thus avoiding unnecessary cache misses.
- */
- static inline bool
- hlist_is_singular_node(struct hlist_node *n, struct hlist_head *h)
- {
- return !n->next && n->pprev == &h->first;
- }
- /**
- * hlist_move_list - Move an hlist
- * @old: hlist_head for old list.
- * @new: hlist_head for new list.
- *
- * 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)
- {
- 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)
- #define hlist_for_each(pos, head) \
- for (pos = (head)->first; pos ; pos = pos->next)
- #define hlist_for_each_safe(pos, n, head) \
- for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \
- pos = n)
- #define hlist_entry_safe(ptr, type, member) \
- ({ typeof(ptr) ____ptr = (ptr); \
- ____ptr ? hlist_entry(____ptr, type, member) : NULL; \
- })
- /**
- * hlist_for_each_entry - iterate 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 hlist_node within the struct.
- */
- #define hlist_for_each_entry(pos, head, member) \
- for (pos = hlist_entry_safe((head)->first, typeof(*(pos)), member);\
- pos; \
- pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member))
- /**
- * hlist_for_each_entry_continue - iterate over a hlist continuing after current point
- * @pos: the type * to use as a loop cursor.
- * @member: the name of the hlist_node within the struct.
- */
- #define hlist_for_each_entry_continue(pos, member) \
- for (pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member);\
- pos; \
- pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member))
- /**
- * hlist_for_each_entry_from - iterate over a hlist continuing from current point
- * @pos: the type * to use as a loop cursor.
- * @member: the name of the hlist_node within the struct.
- */
- #define hlist_for_each_entry_from(pos, member) \
- for (; pos; \
- pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member))
- /**
- * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry
- * @pos: the type * to use as a loop cursor.
- * @n: a &struct hlist_node to use as temporary storage
- * @head: the head for your list.
- * @member: the name of the hlist_node within the struct.
- */
- #define hlist_for_each_entry_safe(pos, n, head, member) \
- for (pos = hlist_entry_safe((head)->first, typeof(*pos), member);\
- pos && ({ n = pos->member.next; 1; }); \
- pos = hlist_entry_safe(n, typeof(*pos), member))
- #endif
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