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SubjectRe: [PATCH] clk: divider: Fix overflow in clk_divider_bestdiv
Hi Mike,

On 07.05.2014 18:24, Tomasz Figa wrote:
> Commit c686078 ("clk: divider: Add round to closest divider") introduced
> a helper function to check whether given divisor is the best one instead
> of direct check. However due to int type used instead of unsigned long
> for passing calculated rates to this function in certain cases an
> overflow could occur, for example when trying to obtain maximum possible
> clock rate by calling clk_round_rate(..., UINT_MAX).
>
> This patch fixes this issue by changing the type of rate, now and best
> arguments of the function to unsigned long, which is the type that
> should be used for clock rates.
>
> Signed-off-by: Tomasz Figa <t.figa@samsung.com>
> ---
> drivers/clk/clk-divider.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
> index c572945..e0b360a 100644
> --- a/drivers/clk/clk-divider.c
> +++ b/drivers/clk/clk-divider.c
> @@ -232,7 +232,7 @@ static int _div_round(struct clk_divider *divider, unsigned long parent_rate,
> }
>
> static bool _is_best_div(struct clk_divider *divider,
> - int rate, int now, int best)
> + unsigned long rate, unsigned long now, unsigned long best)
> {
> if (divider->flags & CLK_DIVIDER_ROUND_CLOSEST)
> return abs(rate - now) < abs(rate - best);
>

Ping. It's quite important fix as the issue makes all Exynos boards
using sdhci-s3c almost unusable.

Best regards,
Tomasz


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