linux-kernel - Re: [PATCH] drm/v3d: Use kvcalloc

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Message-ID: <bf3cd367-81be-a72b-6f23-14005f308a1d@oracle.com>
Date:   Sun, 13 Mar 2022 11:35:49 +0530
From:   Harshit Mogalapalli <harshit.m.mogalapalli@...cle.com>
To:     Joe Perches <joe@...ches.com>
Cc:     dan.carpenter@...cle.com, Emma Anholt <emma@...olt.net>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drm/v3d: Use kvcalloc

Hi Joe,

On 13/03/22 3:57 am, Joe Perches wrote:
> On Sat, 2022-03-12 at 07:26 -0800, Harshit Mogalapalli wrote:
>> kvcalloc is same as kvmalloc_array + __GFP_ZERO.
> []
>> diff --git a/drivers/gpu/drm/v3d/v3d_gem.c b/drivers/gpu/drm/v3d/v3d_gem.c
> []
>> @@ -308,9 +308,8 @@ v3d_lookup_bos(struct drm_device *dev,
>>   		return -EINVAL;
>>   	}
>>   
>> -	job->bo = kvmalloc_array(job->bo_count,
>> -				 sizeof(struct drm_gem_cma_object *),
>> -				 GFP_KERNEL | __GFP_ZERO);
>> +	job->bo = kvcalloc(job->bo_count, sizeof(struct drm_gem_cma_object *),
>> +			   GFP_KERNEL);
>>   	if (!job->bo) {
>>   		DRM_DEBUG("Failed to allocate validated BO pointers\n");
>>   		return -ENOMEM;
> 
> trivia:
> 
> The DRM_DEBUG could also be removed as the the alloc will do a
> a dump_stack on failure.
> 
> 
Thanks for sharing your comments.

DRM_DEBUG statements are present in other parts of code as well. So 
didnot remove it.

Example below:
drivers/gpu/drm/v3d/v3d_gem.c at 322.

  311         job->bo = kvmalloc_array(job->bo_count,
  312                                  sizeof(struct drm_gem_cma_object *),
  313                                  GFP_KERNEL | __GFP_ZERO);
  314         if (!job->bo) {
  315                 DRM_DEBUG("Failed to allocate validated BO 
pointers\n");
  316                 return -ENOMEM;
  317         }
  318
  319         handles = kvmalloc_array(job->bo_count, sizeof(u32), 
GFP_KERNEL);
  320         if (!handles) {
  321                 ret = -ENOMEM;
  322                 DRM_DEBUG("Failed to allocate incoming GEM 
handles\n");
  323                 goto fail;
  324         }


Regards,
Harshit