text: /*
   * Copyright (c) 2010, XenSource Inc.
   * All rights reserved.
   *
   * This  library is  free  software; you  can  redistribute it  and/or
   * modify it under the terms  of the GNU Lesser General Public License
   * as published by  the Free Software Foundation; either  version 2 of
   * the License, or (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful, but
   * WITHOUT  ANY  WARRANTY;  without   even  the  implied  warranty  of
   * MERCHANTABILITY or  FITNESS FOR A PARTICULAR PURPOSE.   See the GNU
   * Lesser General Public License for more details.
   *
   * You should  have received a copy  of the GNU  Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
   * USA
   */
  
  /*
   * kernel 2.6.21 added eventfd(2) support, kernel 2.6.22 eventfds for
   * aio. libaio 0.3.107 updated the header file, but few systems have
   * it. define a custom iocb_common struct instead, and work around a
   * potentially missing sys/eventfd.h. this header should vanish over
   * time.
   */
  
  #ifndef __LIBAIO_COMPAT
  #define __LIBAIO_COMPAT
  
  #include <libaio.h>
  #include <unistd.h>
  #include <sys/syscall.h>
  
  struct __compat_io_iocb_common {
  	char             __pad_buf[8];
  	char             __pad_nbytes[8];
  	long long	offset;
  	long long	__pad3;
  	unsigned	flags;
  	unsigned	resfd;
  };
  
  static inline void __io_set_eventfd(struct iocb *iocb, int eventfd)
  {
  	struct __compat_io_iocb_common *c;
  	c = (struct __compat_io_iocb_common*)&iocb->u.c;
  	c->flags |= (1 << 0);
  	c->resfd = eventfd;
  }
  
  #ifndef SYS_eventfd
  #ifndef __NR_eventfd
  # if defined(__alpha__)
  #  define __NR_eventfd		478
  # elif defined(__arm__)
  #  define __NR_eventfd		(__NR_SYSCALL_BASE+351)
  # elif defined(__ia64__)
  #  define __NR_eventfd		1309
  # elif defined(__i386__)
  #  define __NR_eventfd		323
  # elif defined(__m68k__)
  #  define __NR_eventfd		319
  # elif 0 && defined(__mips__)
  #  error __NR_eventfd?
  #  define __NR_eventfd		(__NR_Linux + 319)
  #  define __NR_eventfd		(__NR_Linux + 278)
  #  define __NR_eventfd		(__NR_Linux + 282)
  # elif defined(__hppa__)
  #  define __NR_eventfd		(__NR_Linux + 304)
  # elif defined(__PPC__) || defined(__powerpc64__)
  #  define __NR_eventfd		307
  # elif defined(__s390__) || defined(__s390x__)
  #  define __NR_eventfd		318
  # elif defined(__sparc__)
  #  define __NR_eventfd		313
  # elif defined(__x86_64__)
  #  define __NR_eventfd		284
  # endif
  #else
  # error __NR_eventfd?
  #endif
  #define SYS_eventfd __NR_eventfd
  #endif
  
  static inline int tapdisk_sys_eventfd(int initval)
  {
  	return syscall(SYS_eventfd, initval, 0);
  }
  
  #endif /* __LIBAIO_COMPAT */
  