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(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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C
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134// 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/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 { 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; /* Bitmask of accepted types */ DECLARE_BITMAP(type_filter, WATCH_TYPE__NR); }; u32 nr_filters; /* Number of filters */ struct watch_type_filter filters[] __counted_by(nr_filters);};
struct watch_queue { struct rcu_head rcu; struct watch_filter __rcu *filter; struct pipe_inode_info *pipe; /* Pipe we use as a buffer, NULL if queue closed */ 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[] */};
/* * 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)
#elsestatic inline int watch_queue_init(struct pipe_inode_info *pipe){ return -ENOPKG;}
#endif
#endif /* _LINUX_WATCH_QUEUE_H */