fs: add ksys_mount() helper; remove in-kernel calls to sys_mount()

Using this helper allows us to avoid the in-kernel calls to the sys_mount()
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_mount().

In the near future, all callers of ksys_mount() should be converted to call
do_mount() directly.

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>

1 files changed, 2 insertions, 2 deletions

diff --git a/init/do_mounts.c b/init/do_mounts.c
index 7cf4f6d..eb768de 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -363,7 +363,7 @@ static void __init get_fs_names(char *page)
 static int __init do_mount_root(char *name, char *fs, int flags, void *data)
 {
 	struct super_block *s;
-	int err = sys_mount(name, "/root", fs, flags, data);
+	int err = ksys_mount(name, "/root", fs, flags, data);
 	if (err)
 		return err;
 
@@ -599,7 +599,7 @@ void __init prepare_namespace(void)
 	mount_root();
 out:
 	devtmpfs_mount("dev");
-	sys_mount(".", "/", NULL, MS_MOVE, NULL);
+	ksys_mount(".", "/", NULL, MS_MOVE, NULL);
 	sys_chroot(".");
 }