On March 12, 2025 4:56:31 PM PDT, Jacob Keller <jacob.e.keller@xxxxxxxxx> wrote: > > >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... Odd = 1 = true is the only same definition. It is a bitwise XOR, or sum mod 1.
