linux-kernel - Re: [PATCH net-next] mlxsw: spectrum: acl: Use struct

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Message-ID: <20190225191708.GA30453@splinter>
Date:   Mon, 25 Feb 2019 21:17:08 +0200
From:   Ido Schimmel <idosch@...sch.org>
To:     "Gustavo A. R. Silva" <gustavo@...eddedor.com>
Cc:     Jiri Pirko <jiri@...lanox.com>, Ido Schimmel <idosch@...lanox.com>,
        "David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH net-next] mlxsw: spectrum: acl: Use struct_size() in
 kzalloc()

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@...eddedor.com>

Reviewed-by: Ido Schimmel <idosch@...lanox.com>

Thanks