Subject: Re: [PATCH 1/8] mm: slab: provide krealloc_array()

From: Mike Rapoport <[email-masked]>
Date: Wed, 28 Oct 2020 10:47:03 +0200

On Tue, Oct 27, 2020 at 01:17:18PM +0100, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <[email-masked]>
> 
> 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 <[email-masked]>
> ---
>  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.