On Mon, Jan 24, 2022 at 02:48:32PM +1100, NeilBrown wrote: > If a filesystem wishes to handle all swap IO itself (via ->direct_IO), Right now it's half ->direct_IO and half ->readpage and about to change with your series, isn't it? > rather than just providing devices addresses for submit_bio(), > SWP_FS_OPS must be set. > Currently the protocol for setting this it to have ->swap_activate > return zero. In that case SWP_FS_OPS is set, and add_swap_extent() > is called for the entire file. > > This is a little clumsy as different return values for ->swap_activate > have quite different meanings, and it makes it hard to search for which > filesystems require SWP_FS_OPS to be set. > > So remove the special meaning of a zero return, and require the > filesystem to set SWP_FS_OPS if it so desires, and to always call > add_swap_extent() as required. > > Currently only NFS and CIFS return zero for add_swap_extent(). > > Signed-off-by: NeilBrown <neilb@xxxxxxx> Otherwise looks good: Reviewed-by: Christoph Hellwig <hch@xxxxxx>
