/*
 * 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, see <http://www.gnu.org/licenses/>.
 */

/*
 * 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 "../../config.h"
#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;
}

#ifdef HAVE_SYS_EVENTFD_H

#include <sys/eventfd.h>

static inline int tapdisk_sys_eventfd(int initval)
{
	return eventfd(initval, 0);
}

#else /* Fallback */
#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

#endif /* __LIBAIO_COMPAT */
