Re: [KJ] [PATCH] is_power_of_2 in ia64mm

Robert P. J. Day
2007-02-16T17:00:54Z

On Fri, 16 Feb 2007, Richard Knutsson wrote:

> Andreas Schwab wrote:
> > Richard Knutsson <ricknu-0@student.ltu.se> 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?
> Otherwise, imho, it should be left as-is.

i think the above change is fine. as long as the final, overall
semantics of the condition are identical, then there's no problem.

rday

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Robert P. J. Day
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