diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 2fbdff6..8f68ecc 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -1008,17 +1008,22 @@ static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
 {
 	struct dentry *dentry = filp->f_path.dentry;
 	struct sysfs_dirent * parent_sd = dentry->d_fsdata;
-	struct sysfs_dirent *pos = filp->private_data;
+	struct sysfs_dirent *pos;
 	enum kobj_ns_type type;
 	const void *ns;
 	ino_t ino;
+	int ret;
 
 	type = sysfs_ns_type(parent_sd);
 	ns = sysfs_info(dentry->d_sb)->ns[type];
 
+	mutex_lock(&sysfs_mutex);
 	if (filp->f_pos == 0) {
 		ino = parent_sd->s_ino;
-		if (filldir(dirent, ".", 1, filp->f_pos, ino, DT_DIR) == 0)
+		mutex_unlock(&sysfs_mutex);
+		ret = filldir(dirent, ".", 1, filp->f_pos, ino, DT_DIR);
+		mutex_lock(&sysfs_mutex);
+		if (!ret)
 			filp->f_pos++;
 	}
 	if (filp->f_pos == 1) {
@@ -1026,16 +1031,19 @@ static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
 			ino = parent_sd->s_parent->s_ino;
 		else
 			ino = parent_sd->s_ino;
-		if (filldir(dirent, "..", 2, filp->f_pos, ino, DT_DIR) == 0)
+		mutex_unlock(&sysfs_mutex);
+		ret = filldir(dirent, "..", 2, filp->f_pos, ino, DT_DIR);
+		mutex_lock(&sysfs_mutex);
+		if (!ret)
 			filp->f_pos++;
 	}
-	mutex_lock(&sysfs_mutex);
+	pos = filp->private_data;
 	for (pos = sysfs_dir_pos(ns, parent_sd, filp->f_pos, pos);
 	     pos;
 	     pos = sysfs_dir_next_pos(ns, parent_sd, filp->f_pos, pos)) {
 		const char * name;
 		unsigned int type;
-		int len, ret;
+		int len;
 
 		name = pos->s_name;
 		len = strlen(name);