linux-kernel - Re: [PATCH 06/10] drm/tegra: Deliver job completion callback to client

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Message-ID: <08af58dc-c044-337b-281f-87dc9071d35e@kapsi.fi>
Date:   Wed, 29 Nov 2017 11:09:48 +0200
From:   Mikko Perttunen <cyndis@...si.fi>
To:     Dmitry Osipenko <digetx@...il.com>,
        Mikko Perttunen <mperttunen@...dia.com>,
        thierry.reding@...il.com, jonathanh@...dia.com
Cc:     dri-devel@...ts.freedesktop.org, linux-tegra@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 06/10] drm/tegra: Deliver job completion callback to
 client

On 16.11.2017 18:40, Dmitry Osipenko wrote:
> On 05.11.2017 14:01, Mikko Perttunen wrote:
>> To allow client drivers to free resources when jobs have completed,
>> deliver job completion callbacks to them. This requires adding
>> reference counting to context objects, as job completion can happen
>> after the userspace application has closed the context. As such,
>> also add kref-based refcounting for contexts.
>>
>> Signed-off-by: Mikko Perttunen <mperttunen@...dia.com>
>> ---
>>  drivers/gpu/drm/tegra/drm.c | 27 ++++++++++++++++++++++++---
>>  drivers/gpu/drm/tegra/drm.h |  4 ++++
>>  2 files changed, 28 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c
>> index 2cdd054520bf..3e2a4a19412e 100644
>> --- a/drivers/gpu/drm/tegra/drm.c
>> +++ b/drivers/gpu/drm/tegra/drm.c
>> @@ -281,8 +281,11 @@ static int tegra_drm_open(struct drm_device *drm, struct drm_file *filp)
>>  	return 0;
>>  }
>>
>> -static void tegra_drm_context_free(struct tegra_drm_context *context)
>> +static void tegra_drm_context_free(struct kref *ref)
>>  {
>> +	struct tegra_drm_context *context =
>> +		container_of(ref, struct tegra_drm_context, ref);
>> +
>>  	context->client->ops->close_channel(context);
>>  	kfree(context);
>>  }
>> @@ -379,6 +382,16 @@ static int host1x_waitchk_copy_from_user(struct host1x_waitchk *dest,
>>  	return 0;
>>  }
>>
>> +static void tegra_drm_job_done(struct host1x_job *job)
>> +{
>> +	struct tegra_drm_context *context = job->callback_data;
>> +
>> +	if (context->client->ops->submit_done)
>> +		context->client->ops->submit_done(context);
>> +
>> +	kref_put(&context->ref, tegra_drm_context_free);
>> +}
>> +
>>  int tegra_drm_submit(struct tegra_drm_context *context,
>>  		     struct drm_tegra_submit *args, struct drm_device *drm,
>>  		     struct drm_file *file)
>> @@ -560,6 +573,9 @@ int tegra_drm_submit(struct tegra_drm_context *context,
>>  	job->syncpt_id = syncpt.id;
>>  	job->timeout = 10000;
>>
>> +	job->done = tegra_drm_job_done;
>> +	job->callback_data = context;
>> +
>>  	if (args->timeout && args->timeout < 10000)
>>  		job->timeout = args->timeout;
>>
>> @@ -567,8 +583,11 @@ int tegra_drm_submit(struct tegra_drm_context *context,
>>  	if (err)
>>  		goto fail;
>>
>> +	kref_get(&context->ref);
>> +
>>  	err = host1x_job_submit(job);
>>  	if (err) {
>> +		kref_put(&context->ref, tegra_drm_context_free);
>>  		host1x_job_unpin(job);
>>  		goto fail;
>>  	}
>> @@ -717,6 +736,8 @@ static int tegra_open_channel(struct drm_device *drm, void *data,
>>  	if (err < 0)
>>  		kfree(context);
>>
>> +	kref_init(&context->ref);
>> +
>>  	mutex_unlock(&fpriv->lock);
>>  	return err;
>>  }
>> @@ -738,7 +759,7 @@ static int tegra_close_channel(struct drm_device *drm, void *data,
>>  	}
>>
>>  	idr_remove(&fpriv->contexts, context->id);
>> -	tegra_drm_context_free(context);
>> +	kref_put(&context->ref, tegra_drm_context_free);
>>
>>  unlock:
>>  	mutex_unlock(&fpriv->lock);
>> @@ -1026,7 +1047,7 @@ static int tegra_drm_context_cleanup(int id, void *p, void *data)
>>  {
>>  	struct tegra_drm_context *context = p;
>>
>> -	tegra_drm_context_free(context);
>> +	kref_put(&context->ref, tegra_drm_context_free);
>>
>
> Probably won't hurt to add and use tegra_drm_context_get()/tegra_drm_context_put().
>

Yeah, maybe we have enough places where this is called for it to make sense.