[PATCH 18/21] init: add an init_mkdir helper

[Christoph Hellwig <hch@xxxxxx>]

Add a simple helper to mkdir with a kernel space file name and switch
the early init code over to it.  Remove the now unused ksys_mkdir.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
 fs/for_init.c                 | 18 ++++++++++++++++++
 fs/internal.h                 |  1 -
 fs/namei.c                    |  2 +-
 include/linux/init_syscalls.h |  1 +
 include/linux/syscalls.h      |  7 -------
 init/do_mounts_initrd.c       |  2 +-
 init/initramfs.c              |  2 +-
 init/noinitramfs.c            |  5 +++--
 8 files changed, 25 insertions(+), 13 deletions(-)

diff --git a/fs/for_init.c b/fs/for_init.c
index 082ff1004f06b3..6ae3305bece1eb 100644
--- a/fs/for_init.c
+++ b/fs/for_init.c
@@ -172,6 +172,24 @@ int __init init_unlink(const char *pathname)
 	return do_unlinkat(AT_FDCWD, getname_kernel(pathname));
 }
 
+int __init init_mkdir(const char *pathname, umode_t mode)
+{
+	struct dentry *dentry;
+	struct path path;
+	int error;
+
+	dentry = kern_path_create(AT_FDCWD, pathname, &path, LOOKUP_DIRECTORY);
+	if (IS_ERR(dentry))
+		return PTR_ERR(dentry);
+	if (!IS_POSIXACL(path.dentry->d_inode))
+		mode &= ~current_umask();
+	error = security_path_mkdir(&path, dentry, mode);
+	if (!error)
+		error = vfs_mkdir(path.dentry->d_inode, dentry, mode);
+	done_path_create(&path, dentry);
+	return error;
+}
+
 int __init init_rmdir(const char *pathname)
 {
 	return do_rmdir(AT_FDCWD, getname_kernel(pathname));
diff --git a/fs/internal.h b/fs/internal.h
index 40b50a222d7a22..4741e591e923bf 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -64,7 +64,6 @@ extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
 			   const char *, unsigned int, struct path *);
 long do_mknodat(int dfd, const char __user *filename, umode_t mode,
 		unsigned int dev);
-long do_mkdirat(int dfd, const char __user *pathname, umode_t mode);
 long do_rmdir(int dfd, struct filename *name);
 long do_unlinkat(int dfd, struct filename *name);
 int may_linkat(struct path *link);
diff --git a/fs/namei.c b/fs/namei.c
index 2f6fa53eb3da28..d6b25dd32f4d50 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3645,7 +3645,7 @@ int vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 }
 EXPORT_SYMBOL(vfs_mkdir);
 
-long do_mkdirat(int dfd, const char __user *pathname, umode_t mode)
+static long do_mkdirat(int dfd, const char __user *pathname, umode_t mode)
 {
 	struct dentry *dentry;
 	struct path path;
diff --git a/include/linux/init_syscalls.h b/include/linux/init_syscalls.h
index 125f55ae3f80b8..d808985231f8f8 100644
--- a/include/linux/init_syscalls.h
+++ b/include/linux/init_syscalls.h
@@ -11,4 +11,5 @@ int __init init_eaccess(const char *filename);
 int __init init_link(const char *oldname, const char *newname);
 int __init init_symlink(const char *oldname, const char *newname);
 int __init init_unlink(const char *pathname);
+int __init init_mkdir(const char *pathname, umode_t mode);
 int __init init_rmdir(const char *pathname);
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 7cdc0d749a049f..5ef77a91382aa5 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -1270,13 +1270,6 @@ int compat_ksys_ipc(u32 call, int first, int second,
  * The following kernel syscall equivalents are just wrappers to fs-internal
  * functions. Therefore, provide stubs to be inlined at the callsites.
  */
-extern long do_mkdirat(int dfd, const char __user *pathname, umode_t mode);
-
-static inline long ksys_mkdir(const char __user *pathname, umode_t mode)
-{
-	return do_mkdirat(AT_FDCWD, pathname, mode);
-}
-
 extern long do_mknodat(int dfd, const char __user *filename, umode_t mode,
 		       unsigned int dev);
 
diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
index a6b447b191dbc8..3f5ac81913dde4 100644
--- a/init/do_mounts_initrd.c
+++ b/init/do_mounts_initrd.c
@@ -81,7 +81,7 @@ static void __init handle_initrd(void)
 	create_dev("/dev/root.old", Root_RAM0);
 	/* mount initrd on rootfs' /root */
 	mount_block_root("/dev/root.old", root_mountflags & ~MS_RDONLY);
-	ksys_mkdir("/old", 0700);
+	init_mkdir("/old", 0700);
 	init_chdir("/old");
 
 	/*
diff --git a/init/initramfs.c b/init/initramfs.c
index 889c470b0c2aba..076e66f11bda8d 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -345,7 +345,7 @@ static int __init do_name(void)
 			state = CopyFile;
 		}
 	} else if (S_ISDIR(mode)) {
-		ksys_mkdir(collected, mode);
+		init_mkdir(collected, mode);
 		init_chown(collected, uid, gid, 0);
 		init_chmod(collected, mode);
 		dir_add(collected, mtime);
diff --git a/init/noinitramfs.c b/init/noinitramfs.c
index fa9cdfa7101d3c..94cc4df74b11f2 100644
--- a/init/noinitramfs.c
+++ b/init/noinitramfs.c
@@ -9,6 +9,7 @@
 #include <linux/stat.h>
 #include <linux/kdev_t.h>
 #include <linux/syscalls.h>
+#include <linux/init_syscalls.h>
 
 /*
  * Create a simple rootfs that is similar to the default initramfs
@@ -17,7 +18,7 @@ static int __init default_rootfs(void)
 {
 	int err;
 
-	err = ksys_mkdir((const char __user __force *) "/dev", 0755);
+	err = init_mkdir("/dev", 0755);
 	if (err < 0)
 		goto out;
 
@@ -27,7 +28,7 @@ static int __init default_rootfs(void)
 	if (err < 0)
 		goto out;
 
-	err = ksys_mkdir((const char __user __force *) "/root", 0700);
+	err = init_mkdir("/root", 0700);
 	if (err < 0)
 		goto out;
 
-- 
2.27.0