Re: [PATCH net-next] nfp: flower: cmsg: use struct_size() helper

[Jakub Kicinski]

On Thu, 7 Feb 2019 21:47:25 -0600, Gustavo A. R. Silva 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 foo {
>     int stuff;
>     void *entry[];
> };
> 
> size = sizeof(struct foo) + count * sizeof(void *);
> instance = alloc(size, GFP_KERNEL);
> 
> Instead of leaving these open-coded and prone to type mistakes, we can
> now use the new struct_size() helper:
> 
> instance = alloc(struct_size(instance, entry, count), GFP_KERNEL);
> 
> Notice that, in this case, variable 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: Jakub Kicinski <jakub.kicinski@xxxxxxxxxxxxx>