Re: [PATCH -v8 3/4] Enable the MS_ASYNC functionality in sys_msync()

[Peter Zijlstra <a.p.zijlstra@chello.nl>]

On Wed, 2008-01-23 at 09:47 +0100, Peter Zijlstra wrote:
> On Wed, 2008-01-23 at 02:21 +0300, Anton Salikhmetov wrote:

> > +static void vma_wrprotect(struct vm_area_struct *vma)
> > +{
> > +	unsigned long addr = vma->vm_start;
> > +	pgd_t *pgd = pgd_offset(vma->vm_mm, addr);
> > +
> > +	while (addr < vma->vm_end) {
> > +		unsigned long next = pgd_addr_end(addr, vma->vm_end);
> > +
> > +		if (!pgd_none_or_clear_bad(pgd))
> > +			vma_wrprotect_pgd_range(vma, pgd, addr, next);
> > +
> > +		++pgd;
> > +		addr = next;
> > +	}
> > +}
> 
> I think you want to pass start, end here too, you might not need to
> sweep the whole vma.

Also, it still doesn't make sense to me why we'd not need to walk the
rmap, it is all the same file after all.