Remove __ASSUME_EVENTFD2, move eventfd to syscalls.list

[Joseph Myers <joseph at codesourcery dot com>]

Given current Linux kernel version requirements, we can assume the
presence of the eventfd2 syscall.  This means that __ASSUME_EVENTFD2
can be removed, and a syscalls.list entry suffices for eventfd instead
of needing a .c file.  This patch implements those changes.

Tested for x86_64 and x86 (not that that means much, given the lack of
testsuite coverage for eventfd).

2016-03-17  Joseph Myers  <joseph@codesourcery.com>

	* sysdeps/unix/sysv/linux/kernel-features.h (__ASSUME_EVENTFD2):
	Remove macro.
	* sysdeps/unix/sysv/linux/eventfd.c: Remove file.
	* sysdeps/unix/sysv/linux/syscalls.list (eventfd): New syscall
	entry.

diff --git a/sysdeps/unix/sysv/linux/eventfd.c b/sysdeps/unix/sysv/linux/eventfd.c
deleted file mode 100644
index ba193ba..0000000
--- a/sysdeps/unix/sysv/linux/eventfd.c
+++ /dev/null
@@ -1,51 +0,0 @@
-/* Copyright (C) 2007-2016 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-
-   The GNU C 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 2.1 of the License, or (at your option) any later version.
-
-   The GNU C 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 the GNU C Library; if not, see
-   <http://www.gnu.org/licenses/>.  */
-
-#include <errno.h>
-#include <sys/eventfd.h>
-#include <sysdep.h>
-#include <kernel-features.h>
-
-
-int
-eventfd (unsigned int count, int flags)
-{
-#ifdef __NR_eventfd2
-  int res = INLINE_SYSCALL (eventfd2, 2, count, flags);
-# ifndef __ASSUME_EVENTFD2
-  if (res != -1 || errno != ENOSYS)
-# endif
-    return res;
-#endif
-
-#ifndef __ASSUME_EVENTFD2
-  /* The old system call has no flag parameter which is bad.  So we have
-     to wait until we have to support to pass additional values to the
-     kernel (sys_indirect) before implementing setting flags like
-     O_NONBLOCK etc.  */
-  if (flags != 0)
-    return INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL);
-
-# ifdef __NR_eventfd
-  return INLINE_SYSCALL (eventfd, 1, count);
-# else
-  return INLINE_SYSCALL_ERROR_RETURN_VALUE (ENOSYS);
-# endif
-#elif !defined __NR_eventfd2
-# error "__ASSUME_EVENTFD2 defined but not __NR_eventfd2"
-#endif
-}
diff --git a/sysdeps/unix/sysv/linux/kernel-features.h b/sysdeps/unix/sysv/linux/kernel-features.h
index 51cd63c..34a7bd2 100644
--- a/sysdeps/unix/sysv/linux/kernel-features.h
+++ b/sysdeps/unix/sysv/linux/kernel-features.h
@@ -83,7 +83,6 @@
    2.6.27.  */
 #define __ASSUME_IN_NONBLOCK	1
 #define __ASSUME_PIPE2		1
-#define __ASSUME_EVENTFD2	1
 #define __ASSUME_SIGNALFD4	1
 #define __ASSUME_DUP3		1
 
diff --git a/sysdeps/unix/sysv/linux/syscalls.list b/sysdeps/unix/sysv/linux/syscalls.list
index afaf033..7ae2541 100644
--- a/sysdeps/unix/sysv/linux/syscalls.list
+++ b/sysdeps/unix/sysv/linux/syscalls.list
@@ -13,6 +13,7 @@ epoll_create	EXTRA	epoll_create	i:i	epoll_create
 epoll_create1	EXTRA	epoll_create1	i:i	epoll_create1
 epoll_ctl	EXTRA	epoll_ctl	i:iiip	epoll_ctl
 epoll_wait	EXTRA	epoll_wait	Ci:ipii	epoll_wait
+eventfd		EXTRA	eventfd2	i:ii	eventfd
 execve		-	execve		i:spp	__execve	execve
 fdatasync	-	fdatasync	Ci:i	fdatasync
 flock		-	flock		i:ii	__flock		flock

-- 
Joseph S. Myers
joseph@codesourcery.com