Re: [PATCH] drm: use kvmalloc_array for drm_malloc*

[Daniel Vetter]

On Tue, May 16, 2017 at 11:06:06AM +0200, Michal Hocko wrote:
> From: Michal Hocko <mhocko@xxxxxxxx>
> 
> drm_malloc* has grown their own kmalloc with vmalloc fallback
> implementations. MM has grown kvmalloc* helpers in the meantime. Let's
> use those because it a) reduces the code and b) MM has a better idea
> how to implement fallbacks (e.g. do not vmalloc before kmalloc is tried
> with __GFP_NORETRY).
> 
> Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>

Shouldn't we go one step further and just remove these wrappers, maybe
with cocci? Especially drm_malloc_gfp is surpremely pointless after this
patch (and drm_malloc_ab probably not that useful either).
-Daniel
> ---
>  include/drm/drm_mem_util.h | 23 ++---------------------
>  1 file changed, 2 insertions(+), 21 deletions(-)
> 
> diff --git a/include/drm/drm_mem_util.h b/include/drm/drm_mem_util.h
> index d0f6cf2e5324..b461e4e4e6db 100644
> --- a/include/drm/drm_mem_util.h
> +++ b/include/drm/drm_mem_util.h
> @@ -43,31 +43,12 @@ static __inline__ void *drm_calloc_large(size_t nmemb, size_t size)
>  /* Modeled after cairo's malloc_ab, it's like calloc but without the zeroing. */
>  static __inline__ void *drm_malloc_ab(size_t nmemb, size_t size)
>  {
> -	if (size != 0 && nmemb > SIZE_MAX / size)
> -		return NULL;
> -
> -	if (size * nmemb <= PAGE_SIZE)
> -	    return kmalloc(nmemb * size, GFP_KERNEL);
> -
> -	return vmalloc(size * nmemb);
> +	return kvmalloc_array(nmemb, size, GFP_KERNEL);
>  }
>  
>  static __inline__ void *drm_malloc_gfp(size_t nmemb, size_t size, gfp_t gfp)
>  {
> -	if (size != 0 && nmemb > SIZE_MAX / size)
> -		return NULL;
> -
> -	if (size * nmemb <= PAGE_SIZE)
> -		return kmalloc(nmemb * size, gfp);
> -
> -	if (gfp & __GFP_RECLAIMABLE) {
> -		void *ptr = kmalloc(nmemb * size,
> -				    gfp | __GFP_NOWARN | __GFP_NORETRY);
> -		if (ptr)
> -			return ptr;
> -	}
> -
> -	return __vmalloc(size * nmemb, gfp, PAGE_KERNEL);
> +	return kvmalloc_array(nmemb, size, gfp);
>  }
>  
>  static __inline void drm_free_large(void *ptr)
> -- 
> 2.11.0
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch