docs: Move binderfs to admin-guide

The documentation is more appropriate for the administrator than for
the internal kernel API section it is currently in.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Christian Brauner <christian@brauner.io>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

2 files changed, 0 insertions, 78 deletions

diff --git a/Documentation/filesystems/binderfs.rst b/Documentation/filesystems/binderfs.rst
deleted file mode 100644
index c009671f8434..000000000000
--- a/Documentation/filesystems/binderfs.rst
+++ /dev/null
@@ -1,68 +0,0 @@
-.. SPDX-License-Identifier: GPL-2.0
-
-The Android binderfs Filesystem
-===============================
-
-Android binderfs is a filesystem for the Android binder IPC mechanism.  It
-allows to dynamically add and remove binder devices at runtime.  Binder devices
-located in a new binderfs instance are independent of binder devices located in
-other binderfs instances.  Mounting a new binderfs instance makes it possible
-to get a set of private binder devices.
-
-Mounting binderfs
------------------
-
-Android binderfs can be mounted with::
-
-  mkdir /dev/binderfs
-  mount -t binder binder /dev/binderfs
-
-at which point a new instance of binderfs will show up at ``/dev/binderfs``.
-In a fresh instance of binderfs no binder devices will be present.  There will
-only be a ``binder-control`` device which serves as the request handler for
-binderfs. Mounting another binderfs instance at a different location will
-create a new and separate instance from all other binderfs mounts.  This is
-identical to the behavior of e.g. ``devpts`` and ``tmpfs``. The Android
-binderfs filesystem can be mounted in user namespaces.
-
-Options
--------
-max
-  binderfs instances can be mounted with a limit on the number of binder
-  devices that can be allocated. The ``max=<count>`` mount option serves as
-  a per-instance limit. If ``max=<count>`` is set then only ``<count>`` number
-  of binder devices can be allocated in this binderfs instance.
-
-Allocating binder Devices
--------------------------
-
-.. _ioctl: http://man7.org/linux/man-pages/man2/ioctl.2.html
-
-To allocate a new binder device in a binderfs instance a request needs to be
-sent through the ``binder-control`` device node.  A request is sent in the form
-of an `ioctl() <ioctl_>`_.
-
-What a program needs to do is to open the ``binder-control`` device node and
-send a ``BINDER_CTL_ADD`` request to the kernel.  Users of binderfs need to
-tell the kernel which name the new binder device should get.  By default a name
-can only contain up to ``BINDERFS_MAX_NAME`` chars including the terminating
-zero byte.
-
-Once the request is made via an `ioctl() <ioctl_>`_ passing a ``struct
-binder_device`` with the name to the kernel it will allocate a new binder
-device and return the major and minor number of the new device in the struct
-(This is necessary because binderfs allocates a major device number
-dynamically.).  After the `ioctl() <ioctl_>`_ returns there will be a new
-binder device located under /dev/binderfs with the chosen name.
-
-Deleting binder Devices
------------------------
-
-.. _unlink: http://man7.org/linux/man-pages/man2/unlink.2.html
-.. _rm: http://man7.org/linux/man-pages/man1/rm.1.html
-
-Binderfs binder devices can be deleted via `unlink() <unlink_>`_.  This means
-that the `rm() <rm_>`_ tool can be used to delete them. Note that the
-``binder-control`` device cannot be deleted since this would make the binderfs
-instance unuseable.  The ``binder-control`` device will be deleted when the
-binderfs instance is unmounted and all references to it have been dropped.
diff --git a/Documentation/filesystems/index.rst b/Documentation/filesystems/index.rst
index 1651173f1118..2de2fe2ab078 100644
--- a/Documentation/filesystems/index.rst
+++ b/Documentation/filesystems/index.rst
@@ -32,13 +32,3 @@ filesystem implementations.
 
    journalling
    fscrypt
-
-Filesystem-specific documentation
-=================================
-
-Documentation for individual filesystem types can be found here.
-
-.. toctree::
-   :maxdepth: 2
-
-   binderfs