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Date:   Sat, 1 Jun 2019 10:19:12 +0200
From:   Boris Brezillon <boris.brezillon@collabora.com>
To:     "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Cc:     Boris Brezillon <bbrezillon@kernel.org>,
        linux-i3c@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] i3c: master: Use struct_size() helper
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In-Reply-To: <20190531173532.GA7141@embeddedor>
References: <20190531173532.GA7141@embeddedor>
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On Fri, 31 May 2019 12:35:32 -0500
"Gustavo A. R. Silva" <gustavo@embeddedor.com> wrote:

> Make use of the struct_size() helper instead of an open-coded version
> in order to avoid any potential type mistakes, in particular in the
> context in which this code is being used.
> 
> So, replace the following form:
> 
> sizeof(*defslvs) + ((ndevs - 1) * sizeof(struct i3c_ccc_dev_desc))
> 
> with:
> 
> struct_size(defslvs, slaves, ndevs - 1)
> 
> This code was detected with the help of Coccinelle.
> 
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
> ---
>  drivers/i3c/master.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
> index b9d2b88928e1..923b04052038 100644
> --- a/drivers/i3c/master.c
> +++ b/drivers/i3c/master.c
> @@ -924,9 +924,8 @@ int i3c_master_defslvs_locked(struct i3c_master_controller *master)
>  		ndevs++;
>  
>  	defslvs = i3c_ccc_cmd_dest_init(&dest, I3C_BROADCAST_ADDR,
> -					sizeof(*defslvs) +
> -					((ndevs - 1) *
> -					 sizeof(struct i3c_ccc_dev_desc)));
> +					struct_size(defslvs, slaves,
> +					ndevs - 1));

ndev - 1 should be aligned on the struct_size open parens, or even
better, be put on one line since it seems to fit the 80-chars limit:

defslvs = i3c_ccc_cmd_dest_init(&dest, I3C_BROADCAST_ADDR,
				struct_size(defslvs, slaves, ndevs - 1));


>  	if (!defslvs)
>  		return -ENOMEM;
>