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Date:   Thu, 15 Jul 2021 03:18:04 +0000
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Subject: [PATCH v2 2/3] docs: binderfs: add section about feature files
From:   Carlos Llamas <cmllamas@google.com>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "=?UTF-8?q?Arve=20Hj=C3=B8nnev=C3=A5g?=" <arve@android.com>,
        Todd Kjos <tkjos@android.com>,
        Martijn Coenen <maco@android.com>,
        Christian Brauner <christian@brauner.io>
Cc:     Joel Fernandes <joel@joelfernandes.org>,
        Steven Moreland <smoreland@google.com>,
        kernel-team@android.com, linux-kernel@vger.kernel.org,
        Carlos Llamas <cmllamas@google.com>
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Document how binder feature files can be used to determine whether a
feature is supported by the binder driver. "oneway_spam_detection" is
used as an example as it is the first available feature file.

Signed-off-by: Carlos Llamas <cmllamas@google.com>
---
 Documentation/admin-guide/binderfs.rst | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/Documentation/admin-guide/binderfs.rst b/Documentation/admin-guide/binderfs.rst
index 199d84314a14..41a4db00df8d 100644
--- a/Documentation/admin-guide/binderfs.rst
+++ b/Documentation/admin-guide/binderfs.rst
@@ -72,3 +72,16 @@ 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 unusable.  The ``binder-control`` device will be deleted when the
 binderfs instance is unmounted and all references to it have been dropped.
+
+Binder features
+---------------
+
+Assuming an instance of binderfs has been mounted at ``/dev/binderfs``, the
+features supported by the binder driver can be located under
+``/dev/binderfs/features/``. The presence of individual files can be tested
+to determine whether a particular feature is supported by the driver.
+
+Example::
+
+        cat /dev/binderfs/features/oneway_spam_detection
+        1
-- 
2.32.0.93.g670b81a890-goog