diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
index 1966e1a0..502c949 100644
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -33,6 +33,7 @@
 extern void sysfs_drop_dentry(struct sysfs_dirent *sd, struct dentry *parent);
 extern int sysfs_setattr(struct dentry *dentry, struct iattr *iattr);
 
+extern spinlock_t sysfs_lock;
 extern struct rw_semaphore sysfs_rename_sem;
 extern struct super_block * sysfs_sb;
 extern const struct file_operations sysfs_dir_operations;