On Tue, Apr 30, 2024 at 4:38 AM Matthew Wilcox wrote: > > On Tue, Apr 30, 2024 at 04:28:41AM +0900, Ryusuke Konishi wrote: > > On Tue, Apr 30, 2024 at 4:22 AM Kairui Song <ryncsn@xxxxxxxxx> wrote: > > > > > > On Tue, Apr 30, 2024 at 3:14 AM Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote: > > > > > > > > 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; > > > > > > > > > > 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. > > > > Wait a minute. > > > > This function returns a key that corresponds to the cache offset of > > the data block, not the disk block number. > > > > Why is returning to bh->b_blocknr an alternative ? > > Am I missing something? > > Sorry, I forgot how b_blocknr was used. What I meant was: > > u64 key = bh->b_folio->index << (PAGE_SHIFT - bmap->b_inode->i_blkbits); > > return key + bh_offset(bh) >> bmap->b_inode->i_blkbits; > > The point is to get rid of the loop. We could simplify this (and make > it ready for bs>PS) by doing: > > loff_t pos = folio_pos(bh->b_folio) + bh_offset(bh); > return pos >> bmap->b_inode->i_blkbits; I see, I understand the idea that it would be better to eliminate the loop. The above conversion looks fine. What are you going to do, Kairui ? Thanks, Ryusuke Konishi
