linux/include/linux/rculist_bl.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_RCULIST_BL_H
#define _LINUX_RCULIST_BL_H

/*
 * RCU-protected bl list version. See include/linux/list_bl.h.
 */
#include <linux/list_bl.h>
#include <linux/rcupdate.h>

static inline void hlist_bl_set_first_rcu(struct hlist_bl_head *h,
					struct hlist_bl_node *n)
{ … }

static inline struct hlist_bl_node *hlist_bl_first_rcu(struct hlist_bl_head *h)
{ … }

/**
 * hlist_bl_del_rcu - deletes entry from hash list without re-initialization
 * @n: the element to delete from the hash list.
 *
 * Note: hlist_bl_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_bl_add_head_rcu()
 * or hlist_bl_del_rcu(), running on this same list.
 * However, it is perfectly legal to run concurrently with
 * the _rcu list-traversal primitives, such as
 * hlist_bl_for_each_entry().
 */
static inline void hlist_bl_del_rcu(struct hlist_bl_node *n)
{ … }

/**
 * hlist_bl_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_bl,
 * 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_bl_add_head_rcu()
 * or hlist_bl_del_rcu(), running on this same list.
 * However, it is perfectly legal to run concurrently with
 * the _rcu list-traversal primitives, such as
 * hlist_bl_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_bl_add_head_rcu(struct hlist_bl_node *n,
					struct hlist_bl_head *h)
{ … }
/**
 * hlist_bl_for_each_entry_rcu - iterate over rcu list of given type
 * @tpos:	the type * to use as a loop cursor.
 * @pos:	the &struct hlist_bl_node to use as a loop cursor.
 * @head:	the head for your list.
 * @member:	the name of the hlist_bl_node within the struct.
 *
 */
#define hlist_bl_for_each_entry_rcu(tpos, pos, head, member) …

#endif