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

From: Jiri Pirko
Date: Wed Jun 05 2019 - 11:25:43 EST

Wed, Jun 05, 2019 at 04:45:16PM CEST, gustavo@xxxxxxxxxxxxxx wrote:
>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@xxxxxxxxxxxxxx>

Acked-by: Jiri Pirko <jiri@xxxxxxxxxxxx>