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Subject[PATCH 13/24] fs: add a kern_mkdir helper
Date
Add a simple helper perform a mkdir with a kernel space file name and use
it in the early init code instead of relying on the implicit
set_fs(KERNEL_DS) there. To do so push the getname from do_mkdirat into the
callers. Remove the now unused ksys_mkdir.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
fs/internal.h | 1 -
fs/namei.c | 14 ++++++++++----
include/linux/fs.h | 1 +
include/linux/syscalls.h | 7 -------
init/do_mounts_initrd.c | 2 +-
init/initramfs.c | 2 +-
init/noinitramfs.c | 4 ++--
7 files changed, 15 insertions(+), 16 deletions(-)

diff --git a/fs/internal.h b/fs/internal.h
index 1e2b425f56ee9e..722d33a66d9645 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, const char __user *pathname);
long do_unlinkat(int dfd, struct filename *name);
long do_symlinkat(const char __user *oldname, int newdfd,
diff --git a/fs/namei.c b/fs/namei.c
index 6daffd59e97270..3545623495d1f4 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3665,7 +3665,7 @@ 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 int do_mkdirat(int dfd, struct filename *name, umode_t mode)
{
struct dentry *dentry;
struct path path;
@@ -3673,7 +3673,7 @@ long do_mkdirat(int dfd, const char __user *pathname, umode_t mode)
unsigned int lookup_flags = LOOKUP_DIRECTORY;

retry:
- dentry = user_path_create(dfd, pathname, &path, lookup_flags);
+ dentry = filename_create(dfd, name, &path, lookup_flags);
if (IS_ERR(dentry))
return PTR_ERR(dentry);

@@ -3687,17 +3687,23 @@ long do_mkdirat(int dfd, const char __user *pathname, umode_t mode)
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
+ putname(name);
return error;
}

+int kern_mkdir(const char *pathname, umode_t mode)
+{
+ return do_mkdirat(AT_FDCWD, getname_kernel(pathname), mode);
+}
+
SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, umode_t, mode)
{
- return do_mkdirat(dfd, pathname, mode);
+ return do_mkdirat(dfd, getname(pathname), mode);
}

SYSCALL_DEFINE2(mkdir, const char __user *, pathname, umode_t, mode)
{
- return do_mkdirat(AT_FDCWD, pathname, mode);
+ return do_mkdirat(AT_FDCWD, getname(pathname), mode);
}

int vfs_rmdir(struct inode *dir, struct dentry *dentry)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 7472ff0b7062d9..3bbeeadf2ddd98 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3677,5 +3677,6 @@ int __init kern_access(const char *filename, int mode);
int __init kern_chown(const char *filename, uid_t user, gid_t group, int flag);
int __init kern_chmod(const char *filename, umode_t mode);
int __init kern_utimes(const char *filename, struct timespec64 *tv, int flags);
+int kern_mkdir(const char *pathname, umode_t mode);

#endif /* _LINUX_FS_H */
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index a2ece4cc8692f5..6aa1cd200425a4 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -1284,13 +1284,6 @@ static inline long ksys_rmdir(const char __user *pathname)
return do_rmdir(AT_FDCWD, pathname);
}

-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_symlinkat(const char __user *oldname, int newdfd,
const char __user *newname);

diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c
index 1cbc9988d2e0ad..b9a749ebe85c2d 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);
+ kern_mkdir("/old", 0700);
kern_chdir("/old");

/*
diff --git a/init/initramfs.c b/init/initramfs.c
index de850d4c6da200..40b97ca5fe8cde 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -344,7 +344,7 @@ static int __init do_name(void)
state = CopyFile;
}
} else if (S_ISDIR(mode)) {
- ksys_mkdir(collected, mode);
+ kern_mkdir(collected, mode);
kern_chown(collected, uid, gid, 0);
kern_chmod(collected, mode);
dir_add(collected, mtime);
diff --git a/init/noinitramfs.c b/init/noinitramfs.c
index fa9cdfa7101d3c..89109c1d633adb 100644
--- a/init/noinitramfs.c
+++ b/init/noinitramfs.c
@@ -17,7 +17,7 @@ static int __init default_rootfs(void)
{
int err;

- err = ksys_mkdir((const char __user __force *) "/dev", 0755);
+ err = kern_mkdir("/dev", 0755);
if (err < 0)
goto out;

@@ -27,7 +27,7 @@ static int __init default_rootfs(void)
if (err < 0)
goto out;

- err = ksys_mkdir((const char __user __force *) "/root", 0700);
+ err = kern_mkdir("/root", 0700);
if (err < 0)
goto out;

--
2.27.0
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