netdev - Re: [PATCH net-next] net: dsa: use struct_size() in devm

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Message-ID: <20190208103239.GB26387@t480s.localdomain>
Date:   Fri, 8 Feb 2019 10:32:39 -0500
From:   Vivien Didelot <vivien.didelot@...il.com>
To:     "Gustavo A. R. Silva" <gustavo@...eddedor.com>
Cc:     Andrew Lunn <andrew@...n.ch>,
        Florian Fainelli <f.fainelli@...il.com>,
        "David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        "Gustavo A. R. Silva" <gustavo@...eddedor.com>
Subject: Re: [PATCH net-next] net: dsa: use struct_size() in devm_kzalloc()

On Thu, 7 Feb 2019 19:16:03 -0600, "Gustavo A. R. Silva" <gustavo@...eddedor.com> 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 = 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@...eddedor.com>

Reviewed-by: Vivien Didelot <vivien.didelot@...il.com>