Re: [PATCH] x86/mm: Fix incorrect for loop count calculation in sync_global_pgds

[Baoquan He <bhe@redhat.com>]

On 05/01/17 at 03:37pm, Yinghai Lu wrote:
> On Mon, May 1, 2017 at 4:41 AM, Baoquan He <bhe@redhat.com> wrote:
> >  arch/x86/mm/init_64.c | 6 ++++--
> >  1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
> > index 15173d3..dbf4f00 100644
> > --- a/arch/x86/mm/init_64.c
> > +++ b/arch/x86/mm/init_64.c
> > @@ -94,12 +94,14 @@ __setup("noexec32=", nonx32_setup);
> >   */
> >  void sync_global_pgds(unsigned long start, unsigned long end)
> >  {
> > -       unsigned long address;
> > +       unsigned long address, address_next;
> >
> > -       for (address = start; address <= end; address += PGDIR_SIZE) {
> > +       for (address = start; address <= end; address = address_next) {
> >                 const pgd_t *pgd_ref = pgd_offset_k(address);
> >                 struct page *page;
> >
> > +               address_next = (address & PGDIR_MASK) + PGDIR_SIZE;
> > +
> >                 if (pgd_none(*pgd_ref))
> >                         continue;
> >
> 
> This one is better than V2.
> 
> It would better if could rename address to addr as Ingo suggested.

Thanks for your checking and suggestion, Yinghai.

Both v1 and v2 are fine to me. As you said, code in v1 is easily
understood, while v2 code is more compact, less line. The line of v1 is
not more than 80. Maybe Ingo can help choose one which he likes better.

Thanks
Baoquan