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
  30 struct eventfd_ctx *eventfd_ctx_get(struct eventfd_ctx *ctx);
  31 void eventfd_ctx_put(struct eventfd_ctx *ctx);
  32 struct file *eventfd_fget(int fd);
  33 struct eventfd_ctx *eventfd_ctx_fdget(int fd);
  34 struct eventfd_ctx *eventfd_ctx_fileget(struct file *file);
  35 int eventfd_signal(struct eventfd_ctx *ctx, int n);
  36
  37 #else /* CONFIG_EVENTFD */
  38
  39 /*
  40  * Ugly ugly ugly error layer to support modules that uses eventfd but
  41  * pretend to work in !CONFIG_EVENTFD configurations. Namely, AIO.
  42  */
  43 static inline struct eventfd_ctx *eventfd_ctx_fdget(int fd)
  44 {
  45         return ERR_PTR(-ENOSYS);
  46 }
  47
  48 static inline int eventfd_signal(struct eventfd_ctx *ctx, int n)
  49 {
  50         return -ENOSYS;
  51 }
  52
  53 static inline void eventfd_ctx_put(struct eventfd_ctx *ctx)
  54 {
  55
  56 }
  57
  58 #endif
  59
  60 #endif /* _LINUX_EVENTFD_H */
  61