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>

diff --git a/Documentation/admin-guide/binderfs.rst b/Documentation/admin-guide/binderfs.rst
new file mode 100644 (file)
index 0000000..c009671
--- /dev/null
+++ b/Documentation/admin-guide/binderfs.rst
@@ -0,0 +1,68 @@
+.. 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/admin-guide/index.rst b/Documentation/admin-guide/index.rst
index 8001917ee012b429954c13b1d26f6ad65a972dc4..24fbe0568eff6c8f903354098b240fca0e97e211 100644 (file)
--- a/Documentation/admin-guide/index.rst
+++ b/Documentation/admin-guide/index.rst
@@ -70,6 +70,7 @@ configure specific aspects of kernel behavior to your liking.
    ras
    bcache
    ext4
+   binderfs
    pm/index
    thunderbolt
    LSM/index

diff --git a/Documentation/filesystems/binderfs.rst b/Documentation/filesystems/binderfs.rst
deleted file mode 100644 (file)
index c009671..0000000
--- 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 1651173f111819ad1cb2d264f7e865783a210e94..2de2fe2ab07862ba458da8715b1e819f8e9309ec 100644 (file)
--- 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