| 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
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| 2 | /* |
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| 3 | * include/linux/eventfd.h |
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| 4 | * |
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| 5 | * Copyright (C) 2007 Davide Libenzi <davidel@xmailserver.org> |
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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/wait.h> |
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| 13 | #include <linux/err.h> |
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| 14 | #include <linux/percpu-defs.h> |
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| 15 | #include <linux/percpu.h> |
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| 16 | #include <linux/sched.h> |
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| 17 | #include <uapi/linux/eventfd.h> |
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| 18 | |
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| 19 | /* |
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| 20 | * CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining |
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| 21 | * new flags, since they might collide with O_* ones. We want |
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| 22 | * to re-use O_* flags that couldn't possibly have a meaning |
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| 23 | * from eventfd, in order to leave a free define-space for |
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| 24 | * shared O_* flags. |
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| 25 | */ |
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| 26 | #define EFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK) |
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| 27 | #define EFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS | EFD_SEMAPHORE) |
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| 28 | |
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| 29 | struct eventfd_ctx; |
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| 30 | struct file; |
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| 31 | |
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| 32 | #ifdef CONFIG_EVENTFD |
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| 33 | |
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| 34 | void eventfd_ctx_put(struct eventfd_ctx *ctx); |
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| 35 | struct file *eventfd_fget(int fd); |
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| 36 | struct eventfd_ctx *eventfd_ctx_fdget(int fd); |
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| 37 | struct eventfd_ctx *eventfd_ctx_fileget(struct file *file); |
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| 38 | void eventfd_signal_mask(struct eventfd_ctx *ctx, __poll_t mask); |
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| 39 | int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_entry_t *wait, |
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| 40 | __u64 *cnt); |
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| 41 | void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt); |
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| 42 | |
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| 43 | static inline bool eventfd_signal_allowed(void) |
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| 44 | { |
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| 45 | return !current->in_eventfd; |
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| 46 | } |
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| 47 | |
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| 48 | #else /* CONFIG_EVENTFD */ |
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| 49 | |
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| 50 | /* |
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| 51 | * Ugly ugly ugly error layer to support modules that uses eventfd but |
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| 52 | * pretend to work in !CONFIG_EVENTFD configurations. Namely, AIO. |
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| 53 | */ |
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| 54 | |
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| 55 | static inline struct eventfd_ctx *eventfd_ctx_fdget(int fd) |
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| 56 | { |
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| 57 | return ERR_PTR(-ENOSYS); |
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| 58 | } |
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| 59 | |
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| 60 | static inline void eventfd_signal_mask(struct eventfd_ctx *ctx, __poll_t mask) |
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| 61 | { |
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| 62 | } |
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| 63 | |
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| 64 | static inline void eventfd_ctx_put(struct eventfd_ctx *ctx) |
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| 65 | { |
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| 66 | |
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| 67 | } |
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| 68 | |
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| 69 | static inline int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, |
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| 70 | wait_queue_entry_t *wait, __u64 *cnt) |
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| 71 | { |
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| 72 | return -ENOSYS; |
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| 73 | } |
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| 74 | |
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| 75 | static inline bool eventfd_signal_allowed(void) |
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| 76 | { |
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| 77 | return true; |
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| 78 | } |
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| 79 | |
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| 80 | static inline void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt) |
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| 81 | { |
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| 82 | |
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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 | static inline void eventfd_signal(struct eventfd_ctx *ctx) |
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| 88 | { |
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| 89 | eventfd_signal_mask(ctx, mask: 0); |
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| 90 | } |
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| 91 | |
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| 92 | #endif /* _LINUX_EVENTFD_H */ |
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| 93 | |
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| 94 | |
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