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Date:   Thu, 22 Jul 2021 15:34:19 +0100
From:   Matthew Wilcox <willy@infradead.org>
To:     Dmitry Osipenko <digetx@gmail.com>
Cc:     linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        linux-fsdevel@vger.kernel.org, "Theodore Y. Ts'o" <tytso@mit.edu>
Subject: Re: [PATCH v14 062/138] mm/migrate: Add folio_migrate_copy()
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References: <20210715033704.692967-1-willy@infradead.org>
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 <a670e7c1-95fb-324f-055f-74dd4c81c0d0@gmail.com>
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On Thu, Jul 22, 2021 at 04:45:59PM +0300, Dmitry Osipenko wrote:
> 22.07.2021 15:29, Matthew Wilcox пишет:
> > On Thu, Jul 22, 2021 at 02:52:28PM +0300, Dmitry Osipenko wrote:
> ...
> > The obvious solution is just to change folio_copy():
> > 
> >  {
> > -       unsigned i, nr = folio_nr_pages(src);
> > +       unsigned i = 0;
> > +       unsigned nr = folio_nr_pages(src);
> > 
> > -       for (i = 0; i < nr; i++) {
> > -               cond_resched();
> > +       for (;;) {
> >                 copy_highpage(folio_page(dst, i), folio_page(src, i));
> > +               if (i++ == nr)
> 
> This works with the ++i precedence change. Thanks!

Thanks for testing!  (and fixing my bug)
I just pushed out an update to for-next with this fix.

> The fs/ and mm/ are mostly outside of my scope, hope you'll figure out
> the buffer-head case soon.

Thanks.  We don't need it fixed yet, but probably in the next six months.