From: David Gow <davidgow@google.com>
To: Matti Vaittinen <mazziesaccount@gmail.com>,
Daniel Latypov <dlatypov@google.com>,
Maxime Ripard <maxime@cerno.tech>,
Benjamin Berg <benjamin@sipsolutions.net>,
Brendan Higgins <brendan.higgins@linux.dev>,
Stephen Boyd <sboyd@kernel.org>,
Shuah Khan <skhan@linuxfoundation.org>,
Rae Moar <rmoar@google.com>
Cc: David Gow <davidgow@google.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J . Wysocki" <rafael@kernel.org>,
Heikki Krogerus <heikki.krogerus@linux.intel.com>,
Jonathan Cameron <jic23@kernel.org>,
Sadiya Kazi <sadiyakazi@google.com>,
Jonathan Corbet <corbet@lwn.net>,
linux-doc@vger.kernel.org, kunit-dev@googlegroups.com,
linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2 4/4] Documentation: kunit: Add usage notes for kunit_add_action()
Date: Thu, 18 May 2023 16:38:46 +0800 [thread overview]
Message-ID: <20230518083849.2631178-4-davidgow@google.com> (raw)
In-Reply-To: <20230518083849.2631178-1-davidgow@google.com>
Add some basic documentation for kunit_add_action() and related
deferred action functions.
Signed-off-by: David Gow <davidgow@google.com>
---
This patch is new in v2.
---
Documentation/dev-tools/kunit/usage.rst | 51 +++++++++++++++++++++++++
1 file changed, 51 insertions(+)
diff --git a/Documentation/dev-tools/kunit/usage.rst b/Documentation/dev-tools/kunit/usage.rst
index 46957d1cbcbb..c2f0ed648385 100644
--- a/Documentation/dev-tools/kunit/usage.rst
+++ b/Documentation/dev-tools/kunit/usage.rst
@@ -615,6 +615,57 @@ For example:
KUNIT_ASSERT_STREQ(test, buffer, "");
}
+Registering Cleanup Actions
+---------------------------
+
+If you need to perform some cleanup beyond simple use of ``kunit_kzalloc``,
+you can register a cusom "deferred action", which is a cleanup function
+run when the test exits (whether cleanly, or via a failed assertion).
+
+Actions are simple functions with no return value, and a single ``void*``
+context argument, and forfil the same role as "cleanup" functions in Python
+and Go tests, "defer" statements in languages which support them, and
+(in some cases) destructors in RAII languages.
+
+These are very useful for unregistering things from global lists, closing
+files or other resources, or freeing resources.
+
+For example:
+
+.. code-block:: C
+
+ static void cleanup_device(void *ctx)
+ {
+ struct device *dev = (struct device *)ctx;
+
+ device_unregister(dev);
+ }
+
+ void example_device_test(struct kunit *test)
+ {
+ struct my_device dev;
+
+ device_register(&dev);
+
+ kunit_add_action(test, &cleanup_device, &dev);
+ }
+
+Note that, for functions like device_unregister which only accept a single
+pointer-sized argument, it's possible to directly cast that function to
+a ``kunit_action_t`` rather than writing a wrapper function, for example:
+
+.. code-block:: C
+
+ kunit_add_action(test, (kunit_action_t *)&device_unregister, &dev);
+
+``kunit_add_action`` can fail if, for example, the system is out of memory.
+You can use ``kunit_add_action_or_reset`` instead which runs the action
+immediately if it cannot be deferred.
+
+If you need more control over when the cleanup function is called, you
+can trigger it early using ``kunit_release_action``, or cancel it entirely
+with ``kunit_remove_action``.
+
Testing Static Functions
------------------------
--
2.40.1.698.g37aff9b760-goog
next prev parent reply other threads:[~2023-05-18 8:39 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-18 8:38 [PATCH v2 1/4] kunit: Add kunit_add_action() to defer a call until test exit David Gow
2023-05-18 8:38 ` [PATCH v2 2/4] kunit: executor_test: Use kunit_add_action() David Gow
2023-05-18 8:38 ` [PATCH v2 3/4] kunit: kmalloc_array: " David Gow
2023-05-18 8:38 ` David Gow [this message]
2023-05-19 8:30 ` [PATCH v2 4/4] Documentation: kunit: Add usage notes for kunit_add_action() Bagas Sanjaya
2023-05-24 21:22 ` Rae Moar
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