linux-kernel - Re: [PATCH 06/15] drm/exynos/ipp: free partially allocated resources on error

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Message-id: <53FE70C4.9020501@samsung.com>
Date:	Thu, 28 Aug 2014 08:59:00 +0900
From:	Joonyoung Shim <jy0922.shim@...sung.com>
To:	Andrzej Hajda <a.hajda@...sung.com>,
	Inki Dae <inki.dae@...sung.com>
Cc:	Marek Szyprowski <m.szyprowski@...sung.com>,
	Seung-Woo Kim <sw0312.kim@...sung.com>,
	Kyungmin Park <kyungmin.park@...sung.com>,
	dri-devel@...ts.freedesktop.org,
	open list <linux-kernel@...r.kernel.org>,
	"moderated list:ARM/S5P EXYNOS AR..." 
	<linux-samsung-soc@...r.kernel.org>,
	Joonyoung Shim <jy0922.shim@...sung.com>
Subject: Re: [PATCH 06/15] drm/exynos/ipp: free partially allocated resources
 on error

Hi,

On 08/27/2014 07:27 PM, Andrzej Hajda wrote:
> On 08/26/2014 07:00 AM, Joonyoung Shim wrote:
>> Hi Andrzej,
>>
>> On 08/22/2014 04:52 PM, Andrzej Hajda wrote:
>>> In case of allocation errors some already allocated buffers
>>> were not freed. The patch fixes it.
>>>
>>> Signed-off-by: Andrzej Hajda <a.hajda@...sung.com>
>>> ---
>>>  drivers/gpu/drm/exynos/exynos_drm_ipp.c | 68 ++++++++++++++++-----------------
>>>  1 file changed, 33 insertions(+), 35 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/exynos/exynos_drm_ipp.c b/drivers/gpu/drm/exynos/exynos_drm_ipp.c
>>> index 060a198..728f3b9 100644
>>> --- a/drivers/gpu/drm/exynos/exynos_drm_ipp.c
>>> +++ b/drivers/gpu/drm/exynos/exynos_drm_ipp.c
>>> @@ -599,6 +599,37 @@ static int ipp_set_mem_node(struct exynos_drm_ippdrv *ippdrv,
>>>  	return ret;
>>>  }
>>>  
>>> +static int ipp_put_mem_node(struct drm_device *drm_dev,
>>> +		struct drm_exynos_ipp_cmd_node *c_node,
>>> +		struct drm_exynos_ipp_mem_node *m_node)
>>> +{
>>> +	int i;
>>> +
>>> +	DRM_DEBUG_KMS("node[0x%x]\n", (int)m_node);
>>> +
>>> +	if (!m_node) {
>>> +		DRM_ERROR("invalid dequeue node.\n");
>>> +		return -EFAULT;
>>> +	}
>>> +
>>> +	DRM_DEBUG_KMS("ops_id[%d]\n", m_node->ops_id);
>>> +
>>> +	/* put gem buffer */
>>> +	for_each_ipp_planar(i) {
>>> +		unsigned long handle = m_node->buf_info.handles[i];
>>> +		if (handle)
>>> +			exynos_drm_gem_put_dma_addr(drm_dev, handle,
>>> +							c_node->filp);
>>> +	}
>>> +
>>> +	/* conditionally remove from queue */
>>> +	if (m_node->list.next)
>> How about do INIT_LIST_HEAD for list in ipp_get_mem_node()?
> 
> I am not sure if it is better. For sure it adds unnecessary
> initialization sequence.

In other words, this NULL checking is unnecessary if you initialize the
list_head by INIT_LIST_HEAD.

> Maybe adding list_is_initialized inline function to list.h would be the
> best solution.

There is just list_empty and we can't know whether list is initialized
or not. I recommend to use initialized list_head.

Thanks.

> 
> Regards
> Andrzej
> 
>>
>>> +		list_del(&m_node->list);
>>> +	kfree(m_node);
>>> +
>>> +	return 0;
>>> +}
>>> +
>>>  static struct drm_exynos_ipp_mem_node
>>>  		*ipp_get_mem_node(struct drm_device *drm_dev,
>>>  		struct drm_file *file,
>>> @@ -634,7 +665,8 @@ static struct drm_exynos_ipp_mem_node
>>>  					qbuf->handle[i], file);
>>>  			if (IS_ERR(addr)) {
>>>  				DRM_ERROR("failed to get addr.\n");
>>> -				goto err_clear;
>>> +				ipp_put_mem_node(drm_dev, c_node, m_node);
>>> +				return ERR_PTR(-EFAULT);
>>>  			}
>>>  
>>>  			buf_info->handles[i] = qbuf->handle[i];
>>> @@ -649,40 +681,6 @@ static struct drm_exynos_ipp_mem_node
>>>  	mutex_unlock(&c_node->mem_lock);
>>>  
>>>  	return m_node;
>>> -
>>> -err_clear:
>>> -	kfree(m_node);
>>> -	return ERR_PTR(-EFAULT);
>>> -}
>>> -
>>> -static int ipp_put_mem_node(struct drm_device *drm_dev,
>>> -		struct drm_exynos_ipp_cmd_node *c_node,
>>> -		struct drm_exynos_ipp_mem_node *m_node)
>>> -{
>>> -	int i;
>>> -
>>> -	DRM_DEBUG_KMS("node[0x%x]\n", (int)m_node);
>>> -
>>> -	if (!m_node) {
>>> -		DRM_ERROR("invalid dequeue node.\n");
>>> -		return -EFAULT;
>>> -	}
>>> -
>>> -	DRM_DEBUG_KMS("ops_id[%d]\n", m_node->ops_id);
>>> -
>>> -	/* put gem buffer */
>>> -	for_each_ipp_planar(i) {
>>> -		unsigned long handle = m_node->buf_info.handles[i];
>>> -		if (handle)
>>> -			exynos_drm_gem_put_dma_addr(drm_dev, handle,
>>> -							c_node->filp);
>>> -	}
>>> -
>>> -	/* delete list in queue */
>>> -	list_del(&m_node->list);
>>> -	kfree(m_node);
>>> -
>>> -	return 0;
>>>  }
>>>  
>>>  static void ipp_free_event(struct drm_pending_event *event)
>>>
>>
> 
> 

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