123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213 |
- /* SPDX-License-Identifier: GPL-2.0 */
- #ifndef LIST_H
- #define LIST_H
- #include <stdbool.h>
- #include <stddef.h>
- /* Are two types/vars the same type (ignoring qualifiers)? */
- #define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
- /**
- * container_of - cast a member of a structure out to the containing structure
- * @ptr: the pointer to the member.
- * @type: the type of the container struct this is embedded in.
- * @member: the name of the member within the struct.
- *
- */
- #define container_of(ptr, type, member) ({ \
- void *__mptr = (void *)(ptr); \
- _Static_assert(__same_type(*(ptr), ((type *)0)->member) || \
- __same_type(*(ptr), void), \
- "pointer type mismatch in container_of()"); \
- ((type *)(__mptr - offsetof(type, member))); })
- #define LIST_POISON1 ((void *) 0x100)
- #define LIST_POISON2 ((void *) 0x122)
- /*
- * 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.
- */
- struct list_head {
- struct list_head *next, *prev;
- };
- #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)
- {
- list->next = list;
- list->prev = list;
- }
- /*
- * 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)
- {
- next->prev = new;
- new->next = next;
- new->prev = prev;
- 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;
- prev->next = next;
- }
- static inline void __list_del_entry(struct list_head *entry)
- {
- __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_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 head->next == head;
- }
- /**
- * 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_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_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_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))
- #endif /* LIST_H */
|