Re: [PATCH] lib: objagg: Use struct_size() in kzalloc()

David Miller
2019-06-06T02:03:57Z

From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Date: Wed, 5 Jun 2019 09:45:16 -0500

> One of the more common cases of allocation size calculations is finding
> the size of a structure that has a zero-sized array at the end, along
> with memory for some number of elements for that array. For example:
>
> struct objagg_stats {
> ...
> struct objagg_obj_stats_info stats_info[];
> };
>
> size = sizeof(*objagg_stats) + sizeof(objagg_stats->stats_info[0]) * count;
> instance = kzalloc(size, GFP_KERNEL);
>
> Instead of leaving these open-coded and prone to type mistakes, we can
> now use the new struct_size() helper:
>
> instance = kzalloc(struct_size(instance, stats_info, count), GFP_KERNEL);
>
> Notice that, in this case, variable alloc_size is not necessary, hence it
> is removed.
>
> This code was detected with the help of Coccinelle.
>
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

Applied.