Re: [PATCH v2] drm/gem: fix not to assign error value to gem name

[김승우 <sw0312.kim@samsung.com>]

Hello, Chris,

On 2013년 06월 27일 17:31, Chris Wilson wrote:
> On Thu, Jun 27, 2013 at 08:58:33AM +0900, Seung-Woo Kim wrote:
>> From: YoungJun Cho <yj44.cho@samsung.com>
>>
>> If idr_alloc() is failed, obj->name can be error value. Also
>> it cleans up duplicated flink processing code.
>>
>> This regression has been introduced in
>>
>> commit 2e928815c1886fe628ed54623aa98d0889cf5509
>> Author: Tejun Heo <tj@kernel.org>
>> Date:   Wed Feb 27 17:04:08 2013 -0800
>>
>>     drm: convert to idr_alloc()
>>
>> Signed-off-by: YoungJun Cho <yj44.cho@samsung.com>
>> Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com>
>> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
> 
> Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
> 
> Minor comment inline.
> 
>> ---
>> change since v1:
>> - Add a regression commit information in commit msg as Chris commented
>>
>>  drivers/gpu/drm/drm_gem.c |   18 +++++++-----------
>>  1 file changed, 7 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
>> index 4321713..c9d7081 100644
>> --- a/drivers/gpu/drm/drm_gem.c
>> +++ b/drivers/gpu/drm/drm_gem.c
>> @@ -453,25 +453,21 @@ drm_gem_flink_ioctl(struct drm_device *dev, void *data,
>>  	spin_lock(&dev->object_name_lock);
>>  	if (!obj->name) {
>>  		ret = idr_alloc(&dev->object_name_idr, obj, 1, 0, GFP_NOWAIT);
>> -		obj->name = ret;
>> -		args->name = (uint64_t) obj->name;
>> -		spin_unlock(&dev->object_name_lock);
>> -		idr_preload_end();
>> -
>>  		if (ret < 0)
>>  			goto err;
> 
> Being pedantic, ret == 0 is also an error - but a programming error
> leading to an object leak. BUG_ON(ret == 0) ?
> -Chris
> 

It seems that idr_alloc() with start id 1 does not return 0, so IMHO,
ret == 0 can be ignored here.

But if you think it needs to consider programming error, I'll add some
assertion. Please let me know.

Thanks and Regards,
- Seung-Woo Kim

-- 
Seung-Woo Kim
Samsung Software R&D Center
--

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