fs: expose do_unlinkat for built-in callers

And make it take a struct filename instead of a user pointer.

Signed-off-by: Christoph Hellwig <[e-mail]>
Signed-off-by: Al Viro <[e-mail]>

fs/internal.h

···
 extern int user_path_mountpoint_at(int, const char __user *, unsigned int, struct path *);
 extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
 			   const char *, unsigned int, struct path *);
+long do_unlinkat(int dfd, struct filename *name);
 
 /*
  * namespace.c

fs/namei.c

···
  * writeout happening, and we don't want to prevent access to the directory
  * while waiting on the I/O.
  */
-static long do_unlinkat(int dfd, const char __user *pathname)
+long do_unlinkat(int dfd, struct filename *name)
 {
 	int error;
-	struct filename *name;
 	struct dentry *dentry;
 	struct path path;
 	struct qstr last;
···
 	struct inode *delegated_inode = NULL;
 	unsigned int lookup_flags = 0;
 retry:
-	name = filename_parentat(dfd, getname(pathname), lookup_flags,
-				&path, &last, &type);
+	name = filename_parentat(dfd, name, lookup_flags, &path, &last, &type);
 	if (IS_ERR(name))
 		return PTR_ERR(name);
 
···
 	mnt_drop_write(path.mnt);
 exit1:
 	path_put(&path);
-	putname(name);
 	if (retry_estale(error, lookup_flags)) {
 		lookup_flags |= LOOKUP_REVAL;
 		inode = NULL;
 		goto retry;
 	}
+	putname(name);
 	return error;
 
 slashes:
···
 	if (flag & AT_REMOVEDIR)
 		return do_rmdir(dfd, pathname);
 
-	return do_unlinkat(dfd, pathname);
+	return do_unlinkat(dfd, getname(pathname));
 }
 
 SYSCALL_DEFINE1(unlink, const char __user *, pathname)
 {
-	return do_unlinkat(AT_FDCWD, pathname);
+	return do_unlinkat(AT_FDCWD, getname(pathname));
 }
 
 int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname)