Re: [PATCH v3 02/12] nilfs2: drop usage of page_index

From: Matthew Wilcox
Date: Mon Apr 29 2024 - 15:14:36 EST


On Tue, Apr 30, 2024 at 03:04:50AM +0800, Kairui Song wrote:
> From: Kairui Song <kasong@xxxxxxxxxxx>
>
> 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@xxxxxxxxxxx>
> Cc: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
> Cc: linux-nilfs@xxxxxxxxxxxxxxx
> ---
> 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_bmap *bmap,
> struct buffer_head *pbh;
> __u64 key;
>
> - key = page_index(bh->b_page) << (PAGE_SHIFT -
> - bmap->b_inode->i_blkbits);
> - for (pbh = page_buffers(bh->b_page); pbh != bh; pbh = pbh->b_this_page)
> + key = bh->b_folio->index << (PAGE_SHIFT - bmap->b_inode->i_blkbits);
> + for (pbh = folio_buffers(bh->b_folio); pbh != bh; pbh = pbh->b_this_page)
> key++;
>
> return key;

Why isn't this entire function simply:

return bh->b_blocknr;