linux-kernel - Re: [PATCH net-next] netfilter: xt_recent: Use struct

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Message-ID: <20190211234520.xjlpm4kqm5h6wvnr@salvia>
Date:   Tue, 12 Feb 2019 00:45:20 +0100
From:   Pablo Neira Ayuso <pablo@...filter.org>
To:     "Gustavo A. R. Silva" <gustavo@...eddedor.com>
Cc:     Jozsef Kadlecsik <kadlec@...ckhole.kfki.hu>,
        Florian Westphal <fw@...len.de>,
        "David S. Miller" <davem@...emloft.net>,
        netfilter-devel@...r.kernel.org, coreteam@...filter.org,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH net-next] netfilter: xt_recent: Use struct_size() in
 kvzalloc()

On Thu, Feb 07, 2019 at 06:56:08PM -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:
> 
> size = struct_size(instance, entry, count);
> instance = alloc(size, GFP_KERNEL)
> 
> Notice that, in this case, variable sz is not necessary, hence it is
> removed.
> 
> This code was detected with the help of Coccinelle.

Applied, thanks.