Re: [PATCH] clk: divider: Fix table round up function

From: Shawn Guo
Date: Wed May 07 2014 - 22:54:10 EST


On Wed, May 07, 2014 at 06:48:52PM +0200, Maxime COQUELIN wrote:
> Commit 1d9fe6b97 ("clk: divider: Fix best div calculation for power-of-two and
> table dividers") introduces a regression in its _table_round_up function.
>
> When the divider passed to this function is greater than the max divider
> available in the table, this function returns table's max divider.
> Problem is that it causes an infinite loop in clk_divider_bestdiv() because
> _next_div() will never return a value greater than maxdiv.
>
> Instead of returning table's max divider, this patch returns INT_MAX.
>
> Reported-by: Fabio Estevam <festevam@xxxxxxxxx>
> Reported-by: Shawn Guo <shawn.guo@xxxxxxxxxxxxx>
> Tested-by: Fabio Estevam <festevam@xxxxxxxxx>
> Cc: Mike Turquette <mike.turquette@xxxxxxxxxx>
> Signed-off-by: Maxime Coquelin <maxime.coquelin@xxxxxx>

Tested-by: Shawn Guo <shawn.guo@xxxxxxxxxxxxx>

Thanks for the fix.

Shawn

> ---
> 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 b3c8396..cf9114a 100644
> --- a/drivers/clk/clk-divider.c
> +++ b/drivers/clk/clk-divider.c
> @@ -158,7 +158,7 @@ static bool _is_valid_div(struct clk_divider *divider, unsigned int div)
> static int _round_up_table(const struct clk_div_table *table, int div)
> {
> const struct clk_div_table *clkt;
> - int up = _get_table_maxdiv(table);
> + int up = INT_MAX;
>
> for (clkt = table; clkt->div; clkt++) {
> if (clkt->div == div)
> --
> 1.9.1
>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/