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Message-Id: <20200720155902.181712-15-hch@lst.de>
Date: Mon, 20 Jul 2020 17:58:52 +0200
From: Christoph Hellwig <hch@....de>
To: Al Viro <viro@...iv.linux.org.uk>,
Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
"Rafael J. Wysocki" <rafael@...nel.org>,
linux-kernel@...r.kernel.org, linux-raid@...r.kernel.org,
linux-fsdevel@...r.kernel.org, linux-api@...r.kernel.org
Subject: [PATCH 14/24] fs: add a kern_mknod helper
Add a simple helper perform a mknod 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_mknodat into the
callers. Remove the now unused ksys_mknod.
Signed-off-by: Christoph Hellwig <hch@....de>
---
fs/internal.h | 2 --
fs/namei.c | 18 +++++++++++++-----
include/linux/fs.h | 1 +
include/linux/syscalls.h | 9 ---------
init/do_mounts.h | 2 +-
init/initramfs.c | 2 +-
init/noinitramfs.c | 5 ++---
7 files changed, 18 insertions(+), 21 deletions(-)
diff --git a/fs/internal.h b/fs/internal.h
index 722d33a66d9645..1e7a72bd183e63 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -62,8 +62,6 @@ extern int filename_lookup(int dfd, struct filename *name, unsigned flags,
struct path *path, struct path *root);
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_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 3545623495d1f4..de97edac21849d 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3584,7 +3584,7 @@ static int may_mknod(umode_t mode)
}
}
-long do_mknodat(int dfd, const char __user *filename, umode_t mode,
+static int do_mknodat(int dfd, struct filename *name, umode_t mode,
unsigned int dev)
{
struct dentry *dentry;
@@ -3594,9 +3594,9 @@ long do_mknodat(int dfd, const char __user *filename, umode_t mode,
error = may_mknod(mode);
if (error)
- return error;
+ goto out_putname;
retry:
- dentry = user_path_create(dfd, filename, &path, lookup_flags);
+ dentry = filename_create(dfd, name, &path, lookup_flags);
if (IS_ERR(dentry))
return PTR_ERR(dentry);
@@ -3625,18 +3625,26 @@ long do_mknodat(int dfd, const char __user *filename, umode_t mode,
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
+out_putname:
+ if (!IS_ERR(name))
+ putname(name);
return error;
}
+int kern_mknod(const char *filename, umode_t mode, unsigned int dev)
+{
+ return do_mknodat(AT_FDCWD, getname_kernel(filename), mode, dev);
+}
+
SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, umode_t, mode,
unsigned int, dev)
{
- return do_mknodat(dfd, filename, mode, dev);
+ return do_mknodat(dfd, getname(filename), mode, dev);
}
SYSCALL_DEFINE3(mknod, const char __user *, filename, umode_t, mode, unsigned, dev)
{
- return do_mknodat(AT_FDCWD, filename, mode, dev);
+ return do_mknodat(AT_FDCWD, getname(filename), mode, dev);
}
int vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 3bbeeadf2ddd98..846a21a9b3e14c 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3678,5 +3678,6 @@ 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);
+int kern_mknod(const char *filename, umode_t mode, unsigned int dev);
#endif /* _LINUX_FS_H */
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 6aa1cd200425a4..3dfcae351a077d 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -1293,15 +1293,6 @@ static inline long ksys_symlink(const char __user *oldname,
return do_symlinkat(oldname, AT_FDCWD, newname);
}
-extern long do_mknodat(int dfd, const char __user *filename, umode_t mode,
- unsigned int dev);
-
-static inline long ksys_mknod(const char __user *filename, umode_t mode,
- unsigned int dev)
-{
- return do_mknodat(AT_FDCWD, filename, mode, dev);
-}
-
extern int do_linkat(int olddfd, const char __user *oldname, int newdfd,
const char __user *newname, int flags);
diff --git a/init/do_mounts.h b/init/do_mounts.h
index c855b3f0e06d19..b9ec1d522f0ce1 100644
--- a/init/do_mounts.h
+++ b/init/do_mounts.h
@@ -16,7 +16,7 @@ extern int root_mountflags;
static inline int create_dev(char *name, dev_t dev)
{
ksys_unlink(name);
- return ksys_mknod(name, S_IFBLK|0600, new_encode_dev(dev));
+ return kern_mknod(name, S_IFBLK|0600, new_encode_dev(dev));
}
#ifdef CONFIG_BLK_DEV_RAM
diff --git a/init/initramfs.c b/init/initramfs.c
index 40b97ca5fe8cde..f32226d0388100 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -351,7 +351,7 @@ static int __init do_name(void)
} else if (S_ISBLK(mode) || S_ISCHR(mode) ||
S_ISFIFO(mode) || S_ISSOCK(mode)) {
if (maybe_link() == 0) {
- ksys_mknod(collected, mode, rdev);
+ kern_mknod(collected, mode, rdev);
kern_chown(collected, uid, gid, 0);
kern_chmod(collected, mode);
do_utime(collected, mtime);
diff --git a/init/noinitramfs.c b/init/noinitramfs.c
index 89109c1d633adb..8048777874e4f1 100644
--- a/init/noinitramfs.c
+++ b/init/noinitramfs.c
@@ -21,9 +21,8 @@ static int __init default_rootfs(void)
if (err < 0)
goto out;
- err = ksys_mknod((const char __user __force *) "/dev/console",
- S_IFCHR | S_IRUSR | S_IWUSR,
- new_encode_dev(MKDEV(5, 1)));
+ err = kern_mknod("/dev/console", S_IFCHR | S_IRUSR | S_IWUSR,
+ new_encode_dev(MKDEV(5, 1)));
if (err < 0)
goto out;
--
2.27.0
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