1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * include/linux/eventfd.h
4 *
5 * Copyright (C) 2007 Davide Libenzi <davidel@xmailserver.org>
6 *
7 */
8
9 #ifndef _LINUX_EVENTFD_H
10 #define _LINUX_EVENTFD_H
11
12 #include <linux/wait.h>
13 #include <linux/err.h>
14 #include <linux/percpu-defs.h>
15 #include <linux/percpu.h>
16 #include <linux/sched.h>
17 #include <uapi/linux/eventfd.h>
18
19 /*
20 * CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining
21 * new flags, since they might collide with O_* ones. We want
22 * to re-use O_* flags that couldn't possibly have a meaning
23 * from eventfd, in order to leave a free define-space for
24 * shared O_* flags.
25 */
26 #define EFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK)
27 #define EFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS | EFD_SEMAPHORE)
28
29 struct eventfd_ctx;
30 struct file;
31
32 #ifdef CONFIG_EVENTFD
33
34 void eventfd_ctx_put(struct eventfd_ctx *ctx);
35 struct file *eventfd_fget(int fd);
36 struct eventfd_ctx *eventfd_ctx_fdget(int fd);
37 struct eventfd_ctx *eventfd_ctx_fileget(struct file *file);
38 __u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n);
39 __u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n, __poll_t mask);
40 int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_entry_t *wait,
41 __u64 *cnt);
42 void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt);
43
eventfd_signal_allowed(void)44 static inline bool eventfd_signal_allowed(void)
45 {
46 return !current->in_eventfd;
47 }
48
49 #else /* CONFIG_EVENTFD */
50
51 /*
52 * Ugly ugly ugly error layer to support modules that uses eventfd but
53 * pretend to work in !CONFIG_EVENTFD configurations. Namely, AIO.
54 */
55
eventfd_ctx_fdget(int fd)56 static inline struct eventfd_ctx *eventfd_ctx_fdget(int fd)
57 {
58 return ERR_PTR(-ENOSYS);
59 }
60
eventfd_signal(struct eventfd_ctx * ctx,__u64 n)61 static inline int eventfd_signal(struct eventfd_ctx *ctx, __u64 n)
62 {
63 return -ENOSYS;
64 }
65
eventfd_signal_mask(struct eventfd_ctx * ctx,__u64 n,unsigned mask)66 static inline int eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n,
67 unsigned mask)
68 {
69 return -ENOSYS;
70 }
71
eventfd_ctx_put(struct eventfd_ctx * ctx)72 static inline void eventfd_ctx_put(struct eventfd_ctx *ctx)
73 {
74
75 }
76
eventfd_ctx_remove_wait_queue(struct eventfd_ctx * ctx,wait_queue_entry_t * wait,__u64 * cnt)77 static inline int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx,
78 wait_queue_entry_t *wait, __u64 *cnt)
79 {
80 return -ENOSYS;
81 }
82
eventfd_signal_allowed(void)83 static inline bool eventfd_signal_allowed(void)
84 {
85 return true;
86 }
87
eventfd_ctx_do_read(struct eventfd_ctx * ctx,__u64 * cnt)88 static inline void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt)
89 {
90
91 }
92
93 #endif
94
95 #endif /* _LINUX_EVENTFD_H */
96
97