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 #ifdef CONFIG_EVENTFD
  12
  13 /* For O_CLOEXEC and O_NONBLOCK */
  14 #include <linux/fcntl.h>
  15
  16 /*
  17  * CAREFUL: Check include/asm-generic/fcntl.h when defining
  18  * new flags, since they might collide with O_* ones. We want
  19  * to re-use O_* flags that couldn't possibly have a meaning
  20  * from eventfd, in order to leave a free define-space for
  21  * shared O_* flags.
  22  */
  23 #define EFD_SEMAPHORE (1 << 0)
  24 #define EFD_CLOEXEC O_CLOEXEC
  25 #define EFD_NONBLOCK O_NONBLOCK
  26
  27 #define EFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK)
  28 #define EFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS | EFD_SEMAPHORE)
  29
  30 struct file *eventfd_fget(int fd);
  31 int eventfd_signal(struct file *file, int n);
  32
  33 #else /* CONFIG_EVENTFD */
  34
  35 #define eventfd_fget(fd) ERR_PTR(-ENOSYS)
  36 static inline int eventfd_signal(struct file *file, int n)
  37 { return 0; }
  38
  39 #endif /* CONFIG_EVENTFD */
  40
  41 #endif /* _LINUX_EVENTFD_H */
  42