Re: [PATCH v2] jiffies: Cast to unsigned long for secs_to_jiffies() conversion

[Thomas Gleixner]

On Fri, Jan 31 2025 at 08:06, Jiri Slaby wrote:
> On 30. 01. 25, 20:26, Easwar Hariharan wrote:
>> While converting users of msecs_to_jiffies(), lkp reported that some
>> range checks would always be true because of the mismatch between the
>> implied int value of secs_to_jiffies() vs the unsigned long
>> return value of the msecs_to_jiffies() calls it was replacing. Fix this
>> by casting secs_to_jiffies() values as unsigned long.
>> 
>> Fixes: b35108a51cf7ba ("jiffies: Define secs_to_jiffies()")
>> CC: stable@xxxxxxxxxxxxxxx # 6.13+
>> CC: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
>> Reported-by: kernel test robot <lkp@xxxxxxxxx>
>> Closes: https://lore.kernel.org/oe-kbuild-all/202501301334.NB6NszQR-lkp@xxxxxxxxx/
>> Signed-off-by: Easwar Hariharan <eahariha@xxxxxxxxxxxxxxxxxxx>
>> ---
>>   include/linux/jiffies.h | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>> 
>> diff --git a/include/linux/jiffies.h b/include/linux/jiffies.h
>> index ed945f42e064..0ea8c9887429 100644
>> --- a/include/linux/jiffies.h
>> +++ b/include/linux/jiffies.h
>> @@ -537,7 +537,7 @@ static __always_inline unsigned long msecs_to_jiffies(const unsigned int m)
>>    *
>>    * Return: jiffies value
>>    */
>> -#define secs_to_jiffies(_secs) ((_secs) * HZ)
>> +#define secs_to_jiffies(_secs) (unsigned long)((_secs) * HZ)
>
> Could you just switch the fun to an inline instead?

It's a macro so it can be used in static initializers.