LXR linux/include/linux/eventfd.h

   1/*
   2 *  include/linux/eventfd.h
   3 *
   4 *  Copyright (C) 2007  Davide Libenzi <davidel@xmailserver.org>
   5 *
   6 */
   7
   8#ifndef _LINUX_EVENTFD_H
   9#define _LINUX_EVENTFD_H
  10
  11#include <linux/fcntl.h>
  12#include <linux/file.h>
  13
  14/*
  15 * CAREFUL: Check include/asm-generic/fcntl.h when defining
  16 * new flags, since they might collide with O_* ones. We want
  17 * to re-use O_* flags that couldn't possibly have a meaning
  18 * from eventfd, in order to leave a free define-space for
  19 * shared O_* flags.
  20 */
  21#define EFD_SEMAPHORE (1 << 0)
  22#define EFD_CLOEXEC O_CLOEXEC
  23#define EFD_NONBLOCK O_NONBLOCK
  24
  25#define EFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK)
  26#define EFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS | EFD_SEMAPHORE)
  27
  28#ifdef CONFIG_EVENTFD
  29
  30struct file *eventfd_file_create(unsigned int count, int flags);
  31struct eventfd_ctx *eventfd_ctx_get(struct eventfd_ctx *ctx);
  32void eventfd_ctx_put(struct eventfd_ctx *ctx);
  33struct file *eventfd_fget(int fd);
  34struct eventfd_ctx *eventfd_ctx_fdget(int fd);
  35struct eventfd_ctx *eventfd_ctx_fileget(struct file *file);
  36int eventfd_signal(struct eventfd_ctx *ctx, int n);
  37
  38#else /* CONFIG_EVENTFD */
  39
  40/*
  41 * Ugly ugly ugly error layer to support modules that uses eventfd but
  42 * pretend to work in !CONFIG_EVENTFD configurations. Namely, AIO.
  43 */
  44static inline struct file *eventfd_file_create(unsigned int count, int flags)
  45{
  46        return ERR_PTR(-ENOSYS);
  47}
  48
  49static inline struct eventfd_ctx *eventfd_ctx_fdget(int fd)
  50{
  51        return ERR_PTR(-ENOSYS);
  52}
  53
  54static inline int eventfd_signal(struct eventfd_ctx *ctx, int n)
  55{
  56        return -ENOSYS;
  57}
  58
  59static inline void eventfd_ctx_put(struct eventfd_ctx *ctx)
  60{
  61
  62}
  63
  64#endif
  65
  66#endif /* _LINUX_EVENTFD_H */
  67
  68