Re: [PATCH RFC v3 for-6.8/block 02/17] xen/blkback: use bdev api in xen_update_blkif_status()

[Yu Kuai <yukuai1@xxxxxxxxxxxxxxx>]

Hi, Jan!

在 2024/01/04 19:06, Jan Kara 写道:
> On Thu 21-12-23 16:56:57, Yu Kuai wrote:
> > From: Yu Kuai <yukuai3@xxxxxxxxxx>
> >
> > Avoid to access bd_inode directly, prepare to remove bd_inode from
> > block_devcie.
> >
> > Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
> > ---
> >   drivers/block/xen-blkback/xenbus.c | 3 +--
> >   1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/drivers/block/xen-blkback/xenbus.c 
> > b/drivers/block/xen-blkback/xenbus.c
> > index e34219ea2b05..e645afa4af57 100644
> > --- a/drivers/block/xen-blkback/xenbus.c
> > +++ b/drivers/block/xen-blkback/xenbus.c
> > @@ -104,8 +104,7 @@ static void xen_update_blkif_status(struct xen_blkif *blkif)
> >                 xenbus_dev_error(blkif->be->dev, err, "block flush");
> >                 return;
> >         }
> > -       invalidate_inode_pages2(
> > -                       blkif->vbd.bdev_handle->bdev->bd_inode->i_mapping);
> > +       invalidate_bdev(blkif->vbd.bdev_handle->bdev);
> This function uses invalidate_inode_pages2() while invalidate_bdev() ends
> up using mapping_try_invalidate() and there are subtle behavioral
> differences between these two (for example invalidate_inode_pages2() tries
> to clean dirty pages using the ->launder_folio method). So I think you'll
> need helper like invalidate_bdev2() for this.
Thanks for reviewing this patch, I know the differenct between then,
what I don't understand is that why using invalidate_inode_pages2()
here. sync_blockdev() is just called and 0 is returned, I think in this
case it's safe to call invalidate_bdev() directly, or am I missing
other things?

Thanks,
Kuai

>                                                                 Honza