Re: [PATCH net-next 1/3] dpll: do not truncate the requested pin frequency before checking it

[Ivan Vecera <ivecera@redhat.com>]

On 9/25/26 1:12 AM, Jakub Kicinski wrote:
> DPLL_A_PIN_FREQUENCY is a u64 on the wire and dpll_pin_freq_set() keeps it
> as one, but dpll_pin_is_freq_supported() takes a u32 while the ranges it
> compares against are u64. The supported-frequency check therefore only
> looks at the low 32 bits, and the full value is what reaches the driver.
> 
> Nothing is hitting this today. Reaching it at all needs a pin-set above
> U32_MAX, which no sane caller sends, and the outcome is mild: a pin
> advertising 10 kHz accepts 0x1_0000_2710, ice narrows it straight back to
> 10 kHz in ice_dpll_pin_freq_set(), so the hardware still ends up on an
> advertised frequency and only the "frequency is not supported by the
> device" rejection goes missing. The other direction - a legitimate request
> above U32_MAX wrapping out of the pin's range - needs a driver advertising
> such a range, and none does; zl3073x_pin_check_freq() refuses one outright.
> 
> So this is types rather than a live bug. Widen the check to match the
> attribute, the ranges and the driver callback instead of adding a U32_MAX
> rejection, so that the second case stays right if such a driver appears.
> dpll_pin_esync_set() already keeps u64 throughout its equivalent loop.
> 
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> ---
>   drivers/dpll/dpll_netlink.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/dpll/dpll_netlink.c b/drivers/dpll/dpll_netlink.c
> index fb24fd53f2e1..e5380d95f238 100644
> --- a/drivers/dpll/dpll_netlink.c
> +++ b/drivers/dpll/dpll_netlink.c
> @@ -608,7 +608,7 @@ dpll_msg_add_pin_ref_sync(struct sk_buff *msg, struct dpll_pin *pin,
>   	return -EMSGSIZE;
>   }
>   
> -static bool dpll_pin_is_freq_supported(struct dpll_pin *pin, u32 freq)
> +static bool dpll_pin_is_freq_supported(struct dpll_pin *pin, u64 freq)
>   {
>   	int fs;
>   

Reviewed-by: Ivan Vecera <ivecera@redhat.com>