134 строки
3.8 KiB
C
134 строки
3.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/* User-mappable watch queue
|
|
*
|
|
* Copyright (C) 2020 Red Hat, Inc. All Rights Reserved.
|
|
* Written by David Howells (dhowells@redhat.com)
|
|
*
|
|
* See Documentation/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 {
|
|
enum watch_notification_type type;
|
|
__u32 subtype_filter[1]; /* Bitmask of subtypes to filter on */
|
|
__u32 info_filter; /* Filter on watch_notification::info */
|
|
__u32 info_mask; /* Mask of relevant bits in info_filter */
|
|
};
|
|
|
|
struct watch_filter {
|
|
union {
|
|
struct rcu_head rcu;
|
|
unsigned long type_filter[2]; /* Bitmask of accepted types */
|
|
};
|
|
u32 nr_filters; /* Number of filters */
|
|
struct watch_type_filter filters[];
|
|
};
|
|
|
|
struct watch_queue {
|
|
struct rcu_head rcu;
|
|
struct watch_filter __rcu *filter;
|
|
struct pipe_inode_info *pipe; /* The pipe we're using as a buffer */
|
|
struct hlist_head watches; /* Contributory watches */
|
|
struct page **notes; /* Preallocated notifications */
|
|
unsigned long *notes_bitmap; /* Allocation bitmap for notes */
|
|
struct kref usage; /* Object usage count */
|
|
spinlock_t lock;
|
|
unsigned int nr_notes; /* Number of notes */
|
|
unsigned int nr_pages; /* Number of pages in notes[] */
|
|
bool defunct; /* T when queues closed */
|
|
};
|
|
|
|
/*
|
|
* Representation of a watch on an object.
|
|
*/
|
|
struct watch {
|
|
union {
|
|
struct rcu_head rcu;
|
|
u32 info_id; /* ID to be OR'd in to info field */
|
|
};
|
|
struct watch_queue __rcu *queue; /* Queue to post events to */
|
|
struct hlist_node queue_node; /* Link in queue->watches */
|
|
struct watch_list __rcu *watch_list;
|
|
struct hlist_node list_node; /* Link in watch_list->watchers */
|
|
const struct cred *cred; /* Creds of the owner of the watch */
|
|
void *private; /* Private data for the watched object */
|
|
u64 id; /* Internal identifier */
|
|
struct kref usage; /* Object usage count */
|
|
};
|
|
|
|
/*
|
|
* List of watches on an object.
|
|
*/
|
|
struct watch_list {
|
|
struct rcu_head rcu;
|
|
struct hlist_head watchers;
|
|
void (*release_watch)(struct watch *);
|
|
spinlock_t lock;
|
|
};
|
|
|
|
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 *))
|
|
{
|
|
INIT_HLIST_HEAD(&wlist->watchers);
|
|
spin_lock_init(&wlist->lock);
|
|
wlist->release_watch = release_watch;
|
|
}
|
|
|
|
static inline void post_watch_notification(struct watch_list *wlist,
|
|
struct watch_notification *n,
|
|
const struct cred *cred,
|
|
u64 id)
|
|
{
|
|
if (unlikely(wlist))
|
|
__post_watch_notification(wlist, n, cred, id);
|
|
}
|
|
|
|
static inline void remove_watch_list(struct watch_list *wlist, u64 id)
|
|
{
|
|
if (wlist) {
|
|
remove_watch_from_object(wlist, NULL, id, true);
|
|
kfree_rcu(wlist, rcu);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* watch_sizeof - Calculate the information part of the size of a watch record,
|
|
* given the structure size.
|
|
*/
|
|
#define watch_sizeof(STRUCT) (sizeof(STRUCT) << WATCH_INFO_LENGTH__SHIFT)
|
|
|
|
#else
|
|
static inline int watch_queue_init(struct pipe_inode_info *pipe)
|
|
{
|
|
return -ENOPKG;
|
|
}
|
|
|
|
#endif
|
|
|
|
#endif /* _LINUX_WATCH_QUEUE_H */
|