linux-kernel - Re: [PATCH 1/4] GPU-DRM-TILCDC: Use kmalloc_array() in kfree_table

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Date:   Thu, 22 Sep 2016 19:55:36 +0300
From:   Jyri Sarha <jsarha@...com>
To:     SF Markus Elfring <elfring@...rs.sourceforge.net>,
        <dri-devel@...ts.freedesktop.org>, David Airlie <airlied@...ux.ie>,
        Tomi Valkeinen <tomi.valkeinen@...com>
CC:     LKML <linux-kernel@...r.kernel.org>,
        <kernel-janitors@...r.kernel.org>,
        Julia Lawall <julia.lawall@...6.fr>
Subject: Re: [PATCH 1/4] GPU-DRM-TILCDC: Use kmalloc_array() in
 kfree_table_init()

On 09/22/16 11:31, SF Markus Elfring wrote:
> From: Markus Elfring <elfring@...rs.sourceforge.net>
> Date: Thu, 22 Sep 2016 09:05:14 +0200
> 
> A multiplication for the size determination of a memory allocation
> indicated that an array data structure should be processed.
> Thus use the corresponding function "kmalloc_array".
> 
> This issue was detected by using the Coccinelle software.
> 
> Signed-off-by: Markus Elfring <elfring@...rs.sourceforge.net>
> ---
>  drivers/gpu/drm/tilcdc/tilcdc_slave_compat.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/tilcdc/tilcdc_slave_compat.c b/drivers/gpu/drm/tilcdc/tilcdc_slave_compat.c
> index f9c79da..8faa28f 100644
> --- a/drivers/gpu/drm/tilcdc/tilcdc_slave_compat.c
> +++ b/drivers/gpu/drm/tilcdc/tilcdc_slave_compat.c
> @@ -32,8 +32,7 @@ static int __init kfree_table_init(struct kfree_table *kft)
>  {
>  	kft->total = 32;
>  	kft->num = 0;
> -	kft->table = kmalloc(kft->total * sizeof(*kft->table),
> -			     GFP_KERNEL);
> +	kft->table = kmalloc_array(kft->total, sizeof(*kft->table), GFP_KERNEL);

I was not sure if it is Ok to call kremalloc() for a pointer that was
previously allocated with kmalloc_array(). And at least it felt pointless.

But if you can confirm that it is ok, then sure I can take the patch.

Thanks,
Jyri

>  	if (!kft->table)
>  		return -ENOMEM;
>  
>