On 3/7/2025 11:36 AM, David Laight wrote: > On Fri, 7 Mar 2025 12:42:41 +0100 > Jiri Slaby <jirislaby@xxxxxxxxxx> wrote: > >> On 07. 03. 25, 12:38, Ingo Molnar wrote: >>> >>> * Jiri Slaby <jirislaby@xxxxxxxxxx> wrote: >>> >>>> On 06. 03. 25, 17:25, Kuan-Wei Chiu wrote: >>>>> Change return type to bool for better clarity. Update the kernel doc >>>>> comment accordingly, including fixing "@value" to "@val" and adjusting >>>>> examples. Also mark the function with __attribute_const__ to allow >>>>> potential compiler optimizations. >>>>> >>>>> Co-developed-by: Yu-Chun Lin <eleanor15x@xxxxxxxxx> >>>>> Signed-off-by: Yu-Chun Lin <eleanor15x@xxxxxxxxx> >>>>> Signed-off-by: Kuan-Wei Chiu <visitorckw@xxxxxxxxx> >>>>> --- >>>>> include/linux/bitops.h | 10 +++++----- >>>>> 1 file changed, 5 insertions(+), 5 deletions(-) >>>>> >>>>> diff --git a/include/linux/bitops.h b/include/linux/bitops.h >>>>> index c1cb53cf2f0f..44e5765b8bec 100644 >>>>> --- a/include/linux/bitops.h >>>>> +++ b/include/linux/bitops.h >>>>> @@ -231,26 +231,26 @@ static inline int get_count_order_long(unsigned long l) >>>>> /** >>>>> * parity8 - get the parity of an u8 value >>>>> - * @value: the value to be examined >>>>> + * @val: the value to be examined >>>>> * >>>>> * Determine the parity of the u8 argument. >>>>> * >>>>> * Returns: >>>>> - * 0 for even parity, 1 for odd parity >>>>> + * false for even parity, true for odd parity >>>> >>>> This occurs somehow inverted to me. When something is in parity means that >>>> it has equal number of 1s and 0s. I.e. return true for even distribution. >>>> Dunno what others think? Or perhaps this should be dubbed odd_parity() when >>>> bool is returned? Then you'd return true for odd. >>> >>> OTOH: >>> >>> - '0' is an even number and is returned for even parity, >>> - '1' is an odd number and is returned for odd parity. >> >> Yes, that used to make sense for me. For bool/true/false, it no longer >> does. But as I wrote, it might be only me... > > No me as well, I've made the same comment before. > When reading code I don't want to have to look up a function definition. > There is even scope for having parity_odd() and parity_even(). > And, with the version that shifts a constant right you want to invert > the constant! > > David This is really a question of whether you expect odd or even parity as the "true" value. I think that would depend on context, and we may not reach a good consensus. I do agree that my brain would jump to "true is even, false is odd". However, I also agree returning the value as 0 for even and 1 for odd kind of made sense before, and updating this to be a bool and then requiring to switch all the callers is a bit obnoxious...
