fs: add ksys_chroot() helper; remove-in kernel calls to sys_chroot()
Using this helper allows us to avoid the in-kernel calls to the
sys_chroot() syscall. The ksys_ prefix denotes that this function is
meant as a drop-in replacement for the syscall. In particular, it uses the
same calling convention as sys_chroot().
In the near future, the fs-external callers of ksys_chroot() should be
converted to use kern_path()/set_fs_root() directly. Then ksys_chroot()
can be moved within sys_chroot() again.
This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
index e8573e1..7129326 100644
--- a/init/do_mounts_initrd.c
+++ b/init/do_mounts_initrd.c
@@ -44,7 +44,7 @@
/* move initrd over / and chdir/chroot in initrd root */
sys_chdir("/root");
ksys_mount(".", "/", NULL, MS_MOVE, NULL);
- sys_chroot(".");
+ ksys_chroot(".");
sys_setsid();
return 0;
}
@@ -83,7 +83,7 @@
/* move initrd to rootfs' /old */
ksys_mount("..", ".", NULL, MS_MOVE, NULL);
/* switch root and cwd back to / of rootfs */
- sys_chroot("..");
+ ksys_chroot("..");
if (new_decode_dev(real_root_dev) == Root_RAM0) {
sys_chdir("/old");