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

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;