[PATCH 4/6] drm/tinydrm: Embed drm_device in tinydrm_device

[Noralf Trønnes]

Den 31.08.2017 12.18, skrev Laurent Pinchart:
> Hi Noralf,
>
> Thank you for the patch.
>
> On Monday, 28 August 2017 20:17:46 EEST Noralf Trønnes wrote:
>> Might as well embed drm_device since tinydrm_device (embeds pipe struct
>> and fbdev pointer) needs to stick around after driver-device unbind to
>> handle open fd's after device removal.
>>
>> Cc: David Lechner <david at lechnology.com>
>> Signed-off-by: Noralf Trønnes <noralf at tronnes.org>
>> ---
>>   drivers/gpu/drm/tinydrm/core/tinydrm-core.c | 44  ++++++++++++-------------
>>   drivers/gpu/drm/tinydrm/core/tinydrm-pipe.c |  2 +-
>>   drivers/gpu/drm/tinydrm/mi0283qt.c          |  8 +++---
>>   drivers/gpu/drm/tinydrm/mipi-dbi.c          | 12 ++++----
>>   drivers/gpu/drm/tinydrm/repaper.c           | 10 +++----
>>   drivers/gpu/drm/tinydrm/st7586.c            | 16 +++++------
>>   include/drm/tinydrm/tinydrm.h               |  9 +++++-
>>   7 files changed, 50 insertions(+), 51 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/tinydrm/core/tinydrm-core.c
>> b/drivers/gpu/drm/tinydrm/core/tinydrm-core.c index 551709e..f11f4cd 100644
>> --- a/drivers/gpu/drm/tinydrm/core/tinydrm-core.c
>> +++ b/drivers/gpu/drm/tinydrm/core/tinydrm-core.c
> [snip]
>
>> @@ -142,23 +142,16 @@ static int tinydrm_init(struct device *parent, struct
>> tinydrm_device *tdev, const struct drm_framebuffer_funcs *fb_funcs,
>>   			struct drm_driver *driver)
>>   {
>> -	struct drm_device *drm;
>> +	struct drm_device *drm = &tdev->drm;
>> +	int ret;
>>
>>   	mutex_init(&tdev->dirty_lock);
>>   	tdev->fb_funcs = fb_funcs;
>>
>> -	/*
>> -	 * We don't embed drm_device, because that prevent us from using
>> -	 * devm_kzalloc() to allocate tinydrm_device in the driver since
>> -	 * drm_dev_unref() frees the structure. The devm_ functions provide
>> -	 * for easy error handling.
> Don't you then need a custom drm_driver.release handler to free the parent
> structure ?

I rely on the fact that drm_device is the first member in the driver
structure and thus it will be freed in drm_dev_release(). A later patch
adds a drm_driver.release function though.

Noralf.

>> -	 */
>> -	drm = drm_dev_alloc(driver, parent);
>> -	if (IS_ERR(drm))
>> -		return PTR_ERR(drm);
>> -
>> -	tdev->drm = drm;
>> -	drm->dev_private = tdev;
>> +	ret = drm_dev_init(drm, driver, parent);
>> +	if (ret)
>> +		return ret;
>> +
>>   	drm_mode_config_init(drm);
>>   	drm->mode_config.funcs = &tinydrm_mode_config_funcs;
>>
> [snip]
>
>> diff --git a/drivers/gpu/drm/tinydrm/mi0283qt.c
>> b/drivers/gpu/drm/tinydrm/mi0283qt.c index 7e5bb7d..77d40c9 100644
>> --- a/drivers/gpu/drm/tinydrm/mi0283qt.c
>> +++ b/drivers/gpu/drm/tinydrm/mi0283qt.c
> [snip]
>
>> @@ -169,7 +169,7 @@ static int mi0283qt_probe(struct spi_device *spi)
>>   	u32 rotation = 0;
>>   	int ret;
>>
>> -	mipi = devm_kzalloc(dev, sizeof(*mipi), GFP_KERNEL);
>> +	mipi = kzalloc(sizeof(*mipi), GFP_KERNEL);
> Where's the related kfree() ?
>
>>   	if (!mipi)
>>   		return -ENOMEM;
> [snip]
>
>> diff --git a/drivers/gpu/drm/tinydrm/repaper.c
>> b/drivers/gpu/drm/tinydrm/repaper.c index 30dc97b..b8fc8eb 100644
>> --- a/drivers/gpu/drm/tinydrm/repaper.c
>> +++ b/drivers/gpu/drm/tinydrm/repaper.c
> [snip]
>
>> @@ -949,7 +949,7 @@ static int repaper_probe(struct spi_device *spi)
>>   		}
>>   	}
>>
>> -	epd = devm_kzalloc(dev, sizeof(*epd), GFP_KERNEL);
>> +	epd = kzalloc(sizeof(*epd), GFP_KERNEL);
> Ditto.
>
>>   	if (!epd)
>>   		return -ENOMEM;
> [snip]
>
>> diff --git a/drivers/gpu/drm/tinydrm/st7586.c
>> b/drivers/gpu/drm/tinydrm/st7586.c index b439956..bc2b905 100644
>> --- a/drivers/gpu/drm/tinydrm/st7586.c
>> +++ b/drivers/gpu/drm/tinydrm/st7586.c
> [snip]
>
>> @@ -349,7 +349,7 @@ static int st7586_probe(struct spi_device *spi)
>>   	u32 rotation = 0;
>>   	int ret;
>>
>> -	mipi = devm_kzalloc(dev, sizeof(*mipi), GFP_KERNEL);
>> +	mipi = kzalloc(sizeof(*mipi), GFP_KERNEL);
> Ang here again.
>
>>   	if (!mipi)
>>   		return -ENOMEM;
> [snip]
>