Re: [KJ] [PATCH] is_power_of_2 in ia64mm

From: Andreas Schwab
Date: Fri Feb 16 2007 - 11:00:33 EST


Richard Knutsson <ricknu-0@xxxxxxxxxxxxxx> writes:

> Andreas Schwab wrote:
>> Richard Knutsson <ricknu-0@xxxxxxxxxxxxxx> writes:
>>
>>
>>> Vignesh Babu BM wrote:
>>>
>>>> @@ -175,7 +176,7 @@ static int __init hugetlb_setup_sz(char *str)
>>>> tr_pages = 0x15557000UL;
>>>> size = memparse(str, &str);
>>>> - if (*str || (size & (size-1)) || !(tr_pages & size) ||
>>>> + if (*str || !is_power_of_2(size) || !(tr_pages & size) ||
>>>> size <= PAGE_SIZE ||
>>>> size >= (1UL << PAGE_SHIFT << MAX_ORDER)) {
>>>> printk(KERN_WARNING "Invalid huge page size specified\n");
>>>>
>>>>
>>> As we talked about before; is this really correct? !is_power_of_2(0) ==
>>> true while (0 & (0-1)) == 0.
>>>
>>
>> size == 0 is also covered by the next two conditions, so the overall value
>> does not change.
>>
> Yes, but is it meant to state that 'size' is not a power of two?

What else can it mean?

Andreas.

--
Andreas Schwab, SuSE Labs, schwab@xxxxxxx
SuSE Linux Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
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