--- /dev/null
+From a6097180d884ddab769fb25588ea8598589c218c Mon Sep 17 00:00:00 2001
+From: NeilBrown <neilb@suse.de>
+Date: Mon, 17 Jan 2022 09:07:26 +1100
+Subject: devtmpfs regression fix: reconfigure on each mount
+
+From: NeilBrown <neilb@suse.de>
+
+commit a6097180d884ddab769fb25588ea8598589c218c upstream.
+
+Prior to Linux v5.4 devtmpfs used mount_single() which treats the given
+mount options as "remount" options, so it updates the configuration of
+the single super_block on each mount.
+
+Since that was changed, the mount options used for devtmpfs are ignored.
+This is a regression which affect systemd - which mounts devtmpfs with
+"-o mode=755,size=4m,nr_inodes=1m".
+
+This patch restores the "remount" effect by calling reconfigure_single()
+
+Fixes: d401727ea0d7 ("devtmpfs: don't mix {ramfs,shmem}_fill_super() with mount_single()")
+Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
+Cc: Al Viro <viro@zeniv.linux.org.uk>
+Signed-off-by: NeilBrown <neilb@suse.de>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/base/devtmpfs.c | 7 +++++++
+ fs/super.c | 4 ++--
+ include/linux/fs_context.h | 2 ++
+ 3 files changed, 11 insertions(+), 2 deletions(-)
+
+--- a/drivers/base/devtmpfs.c
++++ b/drivers/base/devtmpfs.c
+@@ -59,8 +59,15 @@ static struct dentry *public_dev_mount(s
+ const char *dev_name, void *data)
+ {
+ struct super_block *s = mnt->mnt_sb;
++ int err;
++
+ atomic_inc(&s->s_active);
+ down_write(&s->s_umount);
++ err = reconfigure_single(s, flags, data);
++ if (err < 0) {
++ deactivate_locked_super(s);
++ return ERR_PTR(err);
++ }
+ return dget(s->s_root);
+ }
+
+--- a/fs/super.c
++++ b/fs/super.c
+@@ -1423,8 +1423,8 @@ struct dentry *mount_nodev(struct file_s
+ }
+ EXPORT_SYMBOL(mount_nodev);
+
+-static int reconfigure_single(struct super_block *s,
+- int flags, void *data)
++int reconfigure_single(struct super_block *s,
++ int flags, void *data)
+ {
+ struct fs_context *fc;
+ int ret;
+--- a/include/linux/fs_context.h
++++ b/include/linux/fs_context.h
+@@ -142,6 +142,8 @@ extern void put_fs_context(struct fs_con
+ extern int vfs_parse_fs_param_source(struct fs_context *fc,
+ struct fs_parameter *param);
+ extern void fc_drop_locked(struct fs_context *fc);
++int reconfigure_single(struct super_block *s,
++ int flags, void *data);
+
+ /*
+ * sget() wrappers to be called from the ->get_tree() op.