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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /include/linux/watch_queue.h | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'include/linux/watch_queue.h')
-rw-r--r-- | include/linux/watch_queue.h | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/include/linux/watch_queue.h b/include/linux/watch_queue.h new file mode 100644 index 000000000..45cd42f55 --- /dev/null +++ b/include/linux/watch_queue.h @@ -0,0 +1,133 @@ +// 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[]; +}; + +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) + +#else +static inline int watch_queue_init(struct pipe_inode_info *pipe) +{ + return -ENOPKG; +} + +#endif + +#endif /* _LINUX_WATCH_QUEUE_H */ |