[PATCH 2/8] nilfs2: drop usage of page_index

[PATCH 2/8] nilfs2: drop usage of page_index

[Kairui Song]

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.

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 | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/fs/nilfs2/bmap.c b/fs/nilfs2/bmap.c
index 383f0afa2cea..4594a4459862 100644
--- a/fs/nilfs2/bmap.c
+++ b/fs/nilfs2/bmap.c
@@ -453,8 +453,7 @@ __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);
+	key = bh->b_page->index << (PAGE_SHIFT - bmap->b_inode->i_blkbits);
 	for (pbh = page_buffers(bh->b_page); pbh != bh; pbh = pbh->b_this_page)
 		key++;
 
-- 
2.44.0

Re: [PATCH 2/8] nilfs2: drop usage of page_index

[Matthew Wilcox]

On Thu, Apr 18, 2024 at 12:08:36AM +0800, Kairui Song wrote:
> +++ b/fs/nilfs2/bmap.c
> @@ -453,8 +453,7 @@ __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);
> +	key = bh->b_page->index << (PAGE_SHIFT - bmap->b_inode->i_blkbits);

I'd prefer this were

	key = bh->b_folio->index << (PAGE_SHIFT - bmap->b_inode->i_blkbits);

(pages only have a ->index field for historical reasons; I'm trying to
get rid of it)

Re: [PATCH 2/8] nilfs2: drop usage of page_index

[Kairui Song]

On Thu, Apr 18, 2024 at 12:14 AM Matthew Wilcox <willy@infradead.org> wrote:
>
> On Thu, Apr 18, 2024 at 12:08:36AM +0800, Kairui Song wrote:
> > +++ b/fs/nilfs2/bmap.c
> > @@ -453,8 +453,7 @@ __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);
> > +     key = bh->b_page->index << (PAGE_SHIFT - bmap->b_inode->i_blkbits);
>
> I'd prefer this were
>
>         key = bh->b_folio->index << (PAGE_SHIFT - bmap->b_inode->i_blkbits);
>
> (pages only have a ->index field for historical reasons; I'm trying to
> get rid of it)
>

Good suggestion! For easier review I just copied the original logic
from page_index, I will update with folio conventions in V2.