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From:   Yang Shi <shy828301@gmail.com>
Date:   Mon, 24 Apr 2023 14:17:12 -0700
Message-ID: <CAHbLzkoEAJhz8GG91MSM9+wCYVqseSFzBQdVAP78W5WPq26GHQ@mail.gmail.com>
Subject: Re: [RFC 2/8] shmem: convert to use folio_test_hwpoison()
To:     Luis Chamberlain <mcgrof@kernel.org>
Cc:     Matthew Wilcox <willy@infradead.org>, hughd@google.com,
        akpm@linux-foundation.org, brauner@kernel.org, djwong@kernel.org,
        p.raghav@samsung.com, da.gomez@samsung.com,
        a.manzanares@samsung.com, dave@stgolabs.net, yosryahmed@google.com,
        keescook@chromium.org, hare@suse.de, kbusch@kernel.org,
        patches@lists.linux.dev, linux-block@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
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On Fri, Apr 21, 2023 at 8:05=E2=80=AFPM Luis Chamberlain <mcgrof@kernel.org=
> wrote:
>
> On Fri, Apr 21, 2023 at 11:42:53PM +0100, Matthew Wilcox wrote:
> > On Fri, Apr 21, 2023 at 02:43:54PM -0700, Luis Chamberlain wrote:
> > > The PageHWPoison() call can be converted over to the respective folio=
 call
> > > folio_test_hwpoison(). This introduces no functional changes.
> >
> > Um, no.  Nobody should use folio_test_hwpoison(), it's a nonsense.
> >
> > Individual pages are hwpoisoned.  You're only testing the head page
> > if you use folio_test_hwpoison().  There's folio_has_hwpoisoned() to
> > test if _any_ page in the folio is poisoned.  But blindly converting
> > PageHWPoison to folio_test_hwpoison() is wrong.
>
> Thanks! I don't see folio_has_hwpoisoned() though.

We do have PageHasHWPoisoned(), which indicates at least one subpage
is hwpoisoned in the huge page.

You may need to add a folio variant.

>
>   Luis
>