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Sender: Larry Finger <larry.finger@gmail.com>
Message-ID: <96eb9ff2-a687-bbd5-9cb1-4b044f7deae3@lwfinger.net>
Date:   Mon, 4 Sep 2023 19:59:03 -0500
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Subject: Re: [PATCH v2] ssb: Fix division by zero issue in ssb_calc_clock_rate
To:     Rand Deeb <rand.sec96@gmail.com>, Michael Buesch <m@bues.ch>,
        linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     deeb.rand@confident.ru, lvc-project@linuxtesting.org,
        voskresenski.stanislav@confident.ru
References: <20230904232346.34991-1-rand.sec96@gmail.com>
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From:   Larry Finger <Larry.Finger@lwfinger.net>
In-Reply-To: <20230904232346.34991-1-rand.sec96@gmail.com>
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On 9/4/23 18:23, Rand Deeb wrote:
> In ssb_calc_clock_rate(), there is a potential issue where the value of
> m1 could be zero due to initialization using clkfactor_f6_resolv(). This
> situation raised concerns about the possibility of a division by zero
> error.
> 
> We fixed it by following the suggestions provided by Larry Finger
> <Larry.Finger@lwfinger.net> and Michael Büsch <m@bues.ch>. The fix
> involves returning a value of 1 instead of 0 in clkfactor_f6_resolv().
> This modification ensures the proper functioning of the code and
> eliminates the risk of division by zero errors.
> 
> Signed-off-by: Rand Deeb <rand.sec96@gmail.com>
> ---
>   drivers/ssb/main.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/ssb/main.c b/drivers/ssb/main.c
> index 0a26984acb2c..9e54bc7eec66 100644
> --- a/drivers/ssb/main.c
> +++ b/drivers/ssb/main.c
> @@ -835,7 +835,7 @@ static u32 clkfactor_f6_resolve(u32 v)
>   	case SSB_CHIPCO_CLK_F6_7:
>   		return 7;
>   	}
> -	return 0;
> +	return 1;
>   }
Acked-by: Larry Finger <Larry.Finger@lwfinger.net>

Larry

>   
>   /* Calculate the speed the backplane would run at a given set of clockcontrol values */