linux/include/linux/watch_queue.h

// SPDX-License-Identifier: GPL-2.0
/* User-mappable watch queue
 *
 * Copyright (C) 2020 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells ([email protected])
 *
 * See Documentation/core-api/watch_queue.rst
 */

#ifndef _LINUX_WATCH_QUEUE_H
#define _LINUX_WATCH_QUEUE_H

#include <uapi/linux/watch_queue.h>
#include <linux/kref.h>
#include <linux/rcupdate.h>

#ifdef CONFIG_WATCH_QUEUE

struct cred;

struct watch_type_filter { … };

struct watch_filter { … };

struct watch_queue { … };

/*
 * Representation of a watch on an object.
 */
struct watch { … };

/*
 * List of watches on an object.
 */
struct watch_list { … };

extern void __post_watch_notification(struct watch_list *,
				      struct watch_notification *,
				      const struct cred *,
				      u64);
extern struct watch_queue *get_watch_queue(int);
extern void put_watch_queue(struct watch_queue *);
extern void init_watch(struct watch *, struct watch_queue *);
extern int add_watch_to_object(struct watch *, struct watch_list *);
extern int remove_watch_from_object(struct watch_list *, struct watch_queue *, u64, bool);
extern long watch_queue_set_size(struct pipe_inode_info *, unsigned int);
extern long watch_queue_set_filter(struct pipe_inode_info *,
				   struct watch_notification_filter __user *);
extern int watch_queue_init(struct pipe_inode_info *);
extern void watch_queue_clear(struct watch_queue *);

static inline void init_watch_list(struct watch_list *wlist,
				   void (*release_watch)(struct watch *))
{ … }

static inline void post_watch_notification(struct watch_list *wlist,
					   struct watch_notification *n,
					   const struct cred *cred,
					   u64 id)
{ … }

static inline void remove_watch_list(struct watch_list *wlist, u64 id)
{ … }

/**
 * watch_sizeof - Calculate the information part of the size of a watch record,
 * given the structure size.
 */
#define watch_sizeof(STRUCT) …

#else
static inline int watch_queue_init(struct pipe_inode_info *pipe)
{
	return -ENOPKG;
}

#endif

#endif /* _LINUX_WATCH_QUEUE_H */