| 1 |
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| 2 | |
| 3 | * include/linux/eventfd.h
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| 4 | *
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| 5 | * Copyright (C) 2007 Davide Libenzi <[email protected]>
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| 6 | *
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| 7 |
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| 8 |
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| 9 | #ifndef _LINUX_EVENTFD_H
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| 10 | #define _LINUX_EVENTFD_H
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| 11 |
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| 12 | #include <linux/fcntl.h>
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| 13 | #include <linux/wait.h>
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| 14 | #include <linux/err.h>
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| 15 | #include <linux/percpu-defs.h>
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| 16 | #include <linux/percpu.h>
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| 17 |
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| 18 | |
| 19 | * CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining
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| 20 | * new flags, since they might collide with O_* ones. We want
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| 21 | * to re-use O_* flags that couldn't possibly have a meaning
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| 22 | * from eventfd, in order to leave a free define-space for
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| 23 | * shared O_* flags.
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| 24 |
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| 25 | #define EFD_SEMAPHORE (1 << 0)
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| 26 | #define EFD_CLOEXEC O_CLOEXEC
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| 27 | #define EFD_NONBLOCK O_NONBLOCK
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| 28 |
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| 29 | #define EFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK)
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| 30 | #define EFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS | EFD_SEMAPHORE)
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| 31 |
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| 32 | struct eventfd_ctx;
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| 33 | struct file;
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| 34 |
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| 35 | #ifdef CONFIG_EVENTFD
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| 36 |
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| 37 | void eventfd_ctx_put(struct eventfd_ctx *ctx);
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| 38 | struct file *eventfd_fget(int fd);
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| 39 | struct eventfd_ctx *eventfd_ctx_fdget(int fd);
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| 40 | struct eventfd_ctx *eventfd_ctx_fileget(struct file *file);
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| 41 | __u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n);
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| 42 | int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_entry_t *wait,
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| 43 | __u64 *cnt);
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| 44 |
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| 45 | DECLARE_PER_CPU(int, eventfd_wake_count);
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| 46 |
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| 47 | static inline bool eventfd_signal_count(void)
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| 48 | {
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| 49 | return this_cpu_read(eventfd_wake_count);
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| 50 | }
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| 51 |
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| 52 | #else
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| 53 |
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| 54 | |
| 55 | * Ugly ugly ugly error layer to support modules that uses eventfd but
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| 56 | * pretend to work in !CONFIG_EVENTFD configurations. Namely, AIO.
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| 57 |
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| 58 |
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| 59 | static inline struct eventfd_ctx *eventfd_ctx_fdget(int fd)
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| 60 | {
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| 61 | return ERR_PTR(-ENOSYS);
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| 62 | }
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| 63 |
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| 64 | static inline int eventfd_signal(struct eventfd_ctx *ctx, int n)
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| 65 | {
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| 66 | return -ENOSYS;
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| 67 | }
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| 68 |
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| 69 | static inline void eventfd_ctx_put(struct eventfd_ctx *ctx)
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| 70 | {
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| 71 |
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| 72 | }
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| 73 |
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| 74 | static inline int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx,
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| 75 | wait_queue_entry_t *wait, __u64 *cnt)
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| 76 | {
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| 77 | return -ENOSYS;
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| 78 | }
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| 79 |
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| 80 | static inline bool eventfd_signal_count(void)
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| 81 | {
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| 82 | return false;
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| 83 | }
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| 84 |
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| 85 | #endif
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| 86 |
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| 87 | #endif
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| 88 |
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