Unify umount function implementations (bug 16552).

Linux kernel architectures have various arrangements for umount
syscalls.  There is a syscall that takes flags, and an older one that
does not.  Newer architectures have only the one taking flags, under
the name umount2 (or under the name umount, in the ia64 case).  Older
architectures may have both, under the names umount2 and umount (or
under the names umount and oldumount, in the alpha case).  glibc then
has several similar implementations of the umount function (no flags)
in terms of either the __umount2 function, or the corresponding
syscall, or in terms of the old syscall under either of its names.

This patch simplifies the implementations in glibc by always using the
__umount2 function to implement the umount function on all systems
using the Linux kernel.  The linux/generic implementation is moved to
sysdeps/unix/sysv/linux (without any changes to code or comments) and
all the other variants are removed.  (This will have the effect of
causing the new syscall to be used in some cases that previously used
the old one, but as discussed for previous changes, such a change to
the underlying syscalls used is OK.)

There remain two variants of how the __umount2 function is
implemented, either in umount2.S, or, for ia64, in syscalls.list.

Tested with build-many-glibcs.py.

	[BZ #16552]
	* sysdeps/unix/sysv/linux/generic/umount.c: Move to ....
	* sysdeps/unix/sysv/linux/umount.c: ... here.
	* sysdeps/unix/sysv/linux/arm/umount.c: Remove file.
	* sysdeps/unix/sysv/linux/hppa/umount.c: Likewise.
	* sysdeps/unix/sysv/linux/ia64/umount.c: Likewise.
	* sysdeps/unix/sysv/linux/mips/mips64/umount.c: Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/umount.c: Likewise.
	* sysdeps/unix/sysv/linux/umount.S: Likewise.
	* sysdeps/unix/sysv/linux/x86_64/umount.c: Likewise.

9 files changed, 13 insertions, 133 deletions

diff --git a/ChangeLog b/ChangeLog
index b571e4ef02..111623dc70 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,16 @@
+2018-03-26  Joseph Myers  <joseph@codesourcery.com>
+
+	[BZ #16552]
+	* sysdeps/unix/sysv/linux/generic/umount.c: Move to ....
+	* sysdeps/unix/sysv/linux/umount.c: ... here.
+	* sysdeps/unix/sysv/linux/arm/umount.c: Remove file.
+	* sysdeps/unix/sysv/linux/hppa/umount.c: Likewise.
+	* sysdeps/unix/sysv/linux/ia64/umount.c: Likewise.
+	* sysdeps/unix/sysv/linux/mips/mips64/umount.c: Likewise.
+	* sysdeps/unix/sysv/linux/powerpc/powerpc64/umount.c: Likewise.
+	* sysdeps/unix/sysv/linux/umount.S: Likewise.
+	* sysdeps/unix/sysv/linux/x86_64/umount.c: Likewise.
+
 2018-03-26  Andreas Schwab  <schwab@suse.de>
 
 	* elf/elf.h (R_RISCV_BRANCH, R_RISCV_JAL, R_RISCV_CALL)
diff --git a/sysdeps/unix/sysv/linux/arm/umount.c b/sysdeps/unix/sysv/linux/arm/umount.c
deleted file mode 100644
index 87997e029f..0000000000
--- a/sysdeps/unix/sysv/linux/arm/umount.c
+++ /dev/null
@@ -1,30 +0,0 @@
-/* Copyright (C) 2000-2018 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-   Contributed by David Huggins-Daines <dhd@debian.org>, 2000.
-
-   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/>.  */
-
-/* Since we don't have an oldumount system call, do what the kernel
-   does down here.  */
-
-extern long int __umount2 (const char *name, int flags);
-
-long int
-__umount (const char *name)
-{
-  return __umount2 (name, 0);
-}
-
-weak_alias (__umount, umount);
diff --git a/sysdeps/unix/sysv/linux/hppa/umount.c b/sysdeps/unix/sysv/linux/hppa/umount.c
deleted file mode 100644
index 208fbec994..0000000000
--- a/sysdeps/unix/sysv/linux/hppa/umount.c
+++ /dev/null
@@ -1 +0,0 @@
-#include <sysdeps/unix/sysv/linux/mips/mips64/umount.c>
diff --git a/sysdeps/unix/sysv/linux/ia64/umount.c b/sysdeps/unix/sysv/linux/ia64/umount.c
deleted file mode 100644
index 8cf5a7564a..0000000000
--- a/sysdeps/unix/sysv/linux/ia64/umount.c
+++ /dev/null
@@ -1,29 +0,0 @@
-/* umount system call for Linux/ia64.
-   Copyright (C) 2003-2018 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 <sys/mount.h>
-#include <errno.h>
-
-#include <sysdep.h>
-
-/* Unmount a filesystem.  */
-int
-umount (const char *special_file)
-{
-  return INLINE_SYSCALL (umount, 2, special_file, 0);
-}
diff --git a/sysdeps/unix/sysv/linux/mips/mips64/umount.c b/sysdeps/unix/sysv/linux/mips/mips64/umount.c
deleted file mode 100644
index 87997e029f..0000000000
--- a/sysdeps/unix/sysv/linux/mips/mips64/umount.c
+++ /dev/null
@@ -1,30 +0,0 @@
-/* Copyright (C) 2000-2018 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-   Contributed by David Huggins-Daines <dhd@debian.org>, 2000.
-
-   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/>.  */
-
-/* Since we don't have an oldumount system call, do what the kernel
-   does down here.  */
-
-extern long int __umount2 (const char *name, int flags);
-
-long int
-__umount (const char *name)
-{
-  return __umount2 (name, 0);
-}
-
-weak_alias (__umount, umount);
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/umount.c b/sysdeps/unix/sysv/linux/powerpc/powerpc64/umount.c
deleted file mode 100644
index e10b40f96c..0000000000
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/umount.c
+++ /dev/null
@@ -1 +0,0 @@
-#include <sysdeps/unix/sysv/linux/x86_64/umount.c>
diff --git a/sysdeps/unix/sysv/linux/umount.S b/sysdeps/unix/sysv/linux/umount.S
deleted file mode 100644
index e18463e2e6..0000000000
--- a/sysdeps/unix/sysv/linux/umount.S
+++ /dev/null
@@ -1,12 +0,0 @@
-/* This hack is necessary since the kernel people are making "strange"
-   changes.  They simply rename old system calls.  */
-
-#include <sysdep.h>
-#ifdef __NR_oldumount
-PSEUDO (__umount, oldumount, 1)
-#else
-PSEUDO (__umount, umount, 1)
-#endif
-	ret
-PSEUDO_END(__umount)
-weak_alias (__umount, umount)
diff --git a/sysdeps/unix/sysv/linux/generic/umount.c b/sysdeps/unix/sysv/linux/umount.c
index 1c8bea55e0..1c8bea55e0 100644
--- a/sysdeps/unix/sysv/linux/generic/umount.c
+++ b/sysdeps/unix/sysv/linux/umount.c
diff --git a/sysdeps/unix/sysv/linux/x86_64/umount.c b/sysdeps/unix/sysv/linux/x86_64/umount.c
deleted file mode 100644
index 9030774776..0000000000
--- a/sysdeps/unix/sysv/linux/x86_64/umount.c
+++ /dev/null
@@ -1,30 +0,0 @@
-/* Copyright (C) 2000-2018 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-   Contributed by David Huggins-Daines <dhd@debian.org>, 2000.
-
-   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/>.  */
-
-/* Since we don't have an oldumount system call, do what the kernel
-   does down here.  */
-
-extern long int __umount2 (const char *name, int flags);
-
-long int
-__umount (const char *name)
-{
-  return __umount2 (name, 0);
-}
-
-weak_alias (__umount, umount);