Re: [PATCH net-next] mlxsw: spectrum: acl: Use struct_size() in kzalloc()

From: Ido Schimmel
Date: Mon Feb 25 2019 - 14:17:28 EST


On Mon, Feb 25, 2019 at 01:01:32PM -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;
> struct boo entry[];
> };
>
> size = sizeof(struct foo) + count * sizeof(struct boo);
> 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, entry, 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>

Reviewed-by: Ido Schimmel <idosch@xxxxxxxxxxxx>

Thanks