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References: <20240429190500.30979-1-ryncsn@gmail.com> <20240429190500.30979-3-ryncsn@gmail.com>
 <Zi_xeKUSD6C8TNYK@casper.infradead.org>
In-Reply-To: <Zi_xeKUSD6C8TNYK@casper.infradead.org>
From: Kairui Song <ryncsn@gmail.com>
Date: Tue, 30 Apr 2024 03:22:10 +0800
Message-ID: <CAMgjq7D5zwksHxh5c00U82BCsLxYj-_GevZZtAM8xNZO7p-RQQ@mail.gmail.com>
Subject: Re: [PATCH v3 02/12] nilfs2: drop usage of page_index
To: Matthew Wilcox <willy@infradead.org>
Cc: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>, 
	"Huang, Ying" <ying.huang@intel.com>, Chris Li <chrisl@kernel.org>, 
	Barry Song <v-songbaohua@oppo.com>, Ryan Roberts <ryan.roberts@arm.com>, Neil Brown <neilb@suse.de>, 
	Minchan Kim <minchan@kernel.org>, Hugh Dickins <hughd@google.com>, 
	David Hildenbrand <david@redhat.com>, Yosry Ahmed <yosryahmed@google.com>, linux-fsdevel@vger.kernel.org, 
	linux-kernel@vger.kernel.org, Ryusuke Konishi <konishi.ryusuke@gmail.com>, 
	linux-nilfs@vger.kernel.org
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On Tue, Apr 30, 2024 at 3:14=E2=80=AFAM Matthew Wilcox <willy@infradead.org=
> wrote:
>
> On Tue, Apr 30, 2024 at 03:04:50AM +0800, Kairui Song wrote:
> > From: Kairui Song <kasong@tencent.com>
> >
> > page_index is only for mixed usage of page cache and swap cache, for
> > pure page cache usage, the caller can just use page->index instead.
> >
> > It can't be a swap cache page here (being part of buffer head),
> > so just drop it, also convert it to use folio.
> >
> > Signed-off-by: Kairui Song <kasong@tencent.com>
> > Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
> > Cc: linux-nilfs@vger.kernel.org
> > ---
> >  fs/nilfs2/bmap.c | 5 ++---
> >  1 file changed, 2 insertions(+), 3 deletions(-)
> >
> > diff --git a/fs/nilfs2/bmap.c b/fs/nilfs2/bmap.c
> > index 383f0afa2cea..f4e5df0cd720 100644
> > --- a/fs/nilfs2/bmap.c
> > +++ b/fs/nilfs2/bmap.c
> > @@ -453,9 +453,8 @@ __u64 nilfs_bmap_data_get_key(const struct nilfs_bm=
ap *bmap,
> >       struct buffer_head *pbh;
> >       __u64 key;
> >
> > -     key =3D page_index(bh->b_page) << (PAGE_SHIFT -
> > -                                      bmap->b_inode->i_blkbits);
> > -     for (pbh =3D page_buffers(bh->b_page); pbh !=3D bh; pbh =3D pbh->=
b_this_page)
> > +     key =3D bh->b_folio->index << (PAGE_SHIFT - bmap->b_inode->i_blkb=
its);
> > +     for (pbh =3D folio_buffers(bh->b_folio); pbh !=3D bh; pbh =3D pbh=
->b_this_page)
> >               key++;
> >
> >       return key;
>
> Why isn't this entire function simply:
>
>         return bh->b_blocknr;
>

Nice idea, I didn't plan for extra clean up and test for fs code, but
this might be OK to have, will check it.