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Date:   Wed, 28 Oct 2020 10:47:03 +0200
From:   Mike Rapoport <rppt@kernel.org>
To:     Bartosz Golaszewski <brgl@bgdev.pl>
Cc:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Sumit Semwal <sumit.semwal@linaro.org>,
        Gustavo Padovan <gustavo@padovan.org>,
        Christian =?iso-8859-1?Q?K=F6nig?= <christian.koenig@amd.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Borislav Petkov <bp@alien8.de>,
        Tony Luck <tony.luck@intel.com>,
        James Morse <james.morse@arm.com>,
        Robert Richter <rric@kernel.org>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <mripard@kernel.org>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Linus Walleij <linus.walleij@linaro.org>,
        "Michael S . Tsirkin" <mst@redhat.com>,
        Jason Wang <jasowang@redhat.com>,
        Christoph Lameter <cl@linux.com>,
        Pekka Enberg <penberg@kernel.org>,
        David Rientjes <rientjes@google.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Jaroslav Kysela <perex@perex.cz>,
        Takashi Iwai <tiwai@suse.com>, linux-media@vger.kernel.org,
        dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org,
        linux-kernel@vger.kernel.org, linux-edac@vger.kernel.org,
        linux-gpio@vger.kernel.org, kvm@vger.kernel.org,
        virtualization@lists.linux-foundation.org, netdev@vger.kernel.org,
        linux-mm@kvack.org, alsa-devel@alsa-project.org,
        Bartosz Golaszewski <bgolaszewski@baylibre.com>
Subject: Re: [PATCH 1/8] mm: slab: provide krealloc_array()
Message-ID: <20201028084703.GC1428094@kernel.org>
References: <20201027121725.24660-1-brgl@bgdev.pl>
 <20201027121725.24660-2-brgl@bgdev.pl>
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On Tue, Oct 27, 2020 at 01:17:18PM +0100, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> 
> When allocating an array of elements, users should check for
> multiplication overflow or preferably use one of the provided helpers
> like: kmalloc_array().
> 
> There's no krealloc_array() counterpart but there are many users who use
> regular krealloc() to reallocate arrays. Let's provide an actual
> krealloc_array() implementation.
> 
> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> ---
>  include/linux/slab.h | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/include/linux/slab.h b/include/linux/slab.h
> index dd6897f62010..0e6683affee7 100644
> --- a/include/linux/slab.h
> +++ b/include/linux/slab.h
> @@ -592,6 +592,17 @@ static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags)
>  	return __kmalloc(bytes, flags);
>  }
>  

Can you please add kernel-doc here and a word or two about this function
to Documentation/core-api/memory-allocation.rst?

> +static __must_check inline void *
> +krealloc_array(void *p, size_t new_n, size_t new_size, gfp_t flags)
> +{
> +	size_t bytes;
> +
> +	if (unlikely(check_mul_overflow(new_n, new_size, &bytes)))
> +		return NULL;
> +
> +	return krealloc(p, bytes, flags);
> +}
> +
>  /**
>   * kcalloc - allocate memory for an array. The memory is set to zero.
>   * @n: number of elements.
> -- 
> 2.29.1
> 
> 

-- 
Sincerely yours,
Mike.