linux-kernel - Re: [PATCH 2/2] drm/tests: managed: Add a simple test for drmm_managed

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Message-ID: <5ec7lc2cyrfchpudujcbhlka6oqjmaxc24oebzccge3733tugp@iutnntppwzk4>
Date:   Tue, 5 Dec 2023 02:16:48 +0100
From:   Michał Winiarski <michal.winiarski@...el.com>
To:     Maxime Ripard <mripard@...nel.org>
CC:     <intel-xe@...ts.freedesktop.org>,
        <dri-devel@...ts.freedesktop.org>, <linux-kernel@...r.kernel.org>,
        Rodrigo Vivi <rodrigo.vivi@...el.com>,
        "Michal Wajdeczko" <michal.wajdeczko@...el.com>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        "Javier Martinez Canillas" <javierm@...hat.com>,
        Maíra Canal <mcanal@...lia.com>
Subject: Re: [PATCH 2/2] drm/tests: managed: Add a simple test for
 drmm_managed_release

On Thu, Nov 30, 2023 at 09:38:35AM +0100, Maxime Ripard wrote:
> Hi,
> 
> Thanks for creating a test for that, that's really appreciated :)
> 
> On Wed, Nov 29, 2023 at 11:14:12PM +0100, Michał Winiarski wrote:
> > Add a simple test that checks whether the action is indeed called right
> > away and that it is not called on the final drm_dev_put().
> > 
> > Signed-off-by: Michał Winiarski <michal.winiarski@...el.com>
> > ---
> >  drivers/gpu/drm/tests/drm_managed_test.c | 65 ++++++++++++++++++------
> >  1 file changed, 50 insertions(+), 15 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/tests/drm_managed_test.c b/drivers/gpu/drm/tests/drm_managed_test.c
> > index 1652dca11d30c..a645ea42aee56 100644
> > --- a/drivers/gpu/drm/tests/drm_managed_test.c
> > +++ b/drivers/gpu/drm/tests/drm_managed_test.c
> > @@ -12,6 +12,8 @@
> >  #define TEST_TIMEOUT_MS	100
> >  
> >  struct managed_test_priv {
> > +	struct drm_device *drm;
> > +	struct device *dev;
> >  	bool action_done;
> >  	wait_queue_head_t action_wq;
> >  };
> > @@ -26,42 +28,75 @@ static void drm_action(struct drm_device *drm, void *ptr)
> >  
> >  static void drm_test_managed_run_action(struct kunit *test)
> >  {
> > -	struct managed_test_priv *priv;
> > -	struct drm_device *drm;
> > -	struct device *dev;
> > +	struct managed_test_priv *priv = test->priv;
> >  	int ret;
> >  
> > -	priv = kunit_kzalloc(test, sizeof(*priv), GFP_KERNEL);
> > -	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv);
> > -	init_waitqueue_head(&priv->action_wq);
> > +	ret = drmm_add_action_or_reset(priv->drm, drm_action, priv);
> > +	KUNIT_EXPECT_EQ(test, ret, 0);
> >  
> > -	dev = drm_kunit_helper_alloc_device(test);
> > -	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, dev);
> > +	ret = drm_dev_register(priv->drm, 0);
> > +	KUNIT_ASSERT_EQ(test, ret, 0);
> > +
> > +	drm_dev_unregister(priv->drm);
> > +	drm_kunit_helper_free_device(test, priv->dev);
> 
> I think we'll need two patches here, one to convert to having an init
> function, and one to actually add the new test, it's pretty confusing as
> it is.
> 
> >  
> > -	drm = __drm_kunit_helper_alloc_drm_device(test, dev, sizeof(*drm), 0, DRIVER_MODESET);
> > -	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, drm);
> > +	ret = wait_event_interruptible_timeout(priv->action_wq, priv->action_done,
> > +					       msecs_to_jiffies(TEST_TIMEOUT_MS));
> > +	KUNIT_EXPECT_GT(test, ret, 0);
> > +}
> >  
> > -	ret = drmm_add_action_or_reset(drm, drm_action, priv);
> > +static void drm_test_managed_release_action(struct kunit *test)
> > +{
> > +	struct managed_test_priv *priv = test->priv;
> > +	int ret;
> > +
> > +	ret = drmm_add_action_or_reset(priv->drm, drm_action, priv);
> >  	KUNIT_EXPECT_EQ(test, ret, 0);
> >  
> > -	ret = drm_dev_register(drm, 0);
> > +	ret = drm_dev_register(priv->drm, 0);
> >  	KUNIT_ASSERT_EQ(test, ret, 0);
> >  
> > -	drm_dev_unregister(drm);
> > -	drm_kunit_helper_free_device(test, dev);
> > +	drmm_release_action(priv->drm, drm_action, priv);
> > +	KUNIT_EXPECT_TRUE(test, priv->action_done);
> > +	priv->action_done = false;
> > +
> > +	drm_dev_unregister(priv->drm);
> > +	drm_kunit_helper_free_device(test, priv->dev);
> >  
> >  	ret = wait_event_interruptible_timeout(priv->action_wq, priv->action_done,
> >  					       msecs_to_jiffies(TEST_TIMEOUT_MS));
> > -	KUNIT_EXPECT_GT(test, ret, 0);
> > +	KUNIT_EXPECT_EQ(test, ret, 0);
> > +}
> > +
> > +static int drm_managed_test_init(struct kunit *test)
> > +{
> > +	struct managed_test_priv *priv;
> > +
> > +	priv = kunit_kzalloc(test, sizeof(*priv), GFP_KERNEL);
> > +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv);
> > +	init_waitqueue_head(&priv->action_wq);
> 
> Also, I know that it was there before, but I'm not sure it's valid from
> a lifetime point of view. Or at least, we have to think hard enough
> about it to just remove that construct
> 
> > +	priv->dev = drm_kunit_helper_alloc_device(test);
> > +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv->dev);
> > +
> > +	priv->drm = __drm_kunit_helper_alloc_drm_device(test, priv->dev, sizeof(*priv->drm),
> > +							0, DRIVER_MODESET);
> > +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv->drm);
> 
> For example by storing the drm_device struct in the priv structure
> directly, and thus everything will just work out.

Sure, makes sense, I'll include it in the patch that moves device alloc
to .init().

Thanks,
-Michał

> 
> Maxime