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charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, May 12, 2026 at 6:50=E2=80=AFPM Baoquan He w= rote: > > This simplifies codes and makes logic clearer. And also makes later any > new swap device type being added easier to handle. > > Currently there are three types of swap devices: bdev_fs, bdev_sync > and bdev_async, and only operations read_folio and write_folio are > included. In the future, there could be more swap device types added > and more appropriate opeations adapted into swap_ops. opeations -> operations > > Suggested-by: Chris Li > Acked-by: Chris Li > Co-developed-by: Barry Song > Signed-off-by: Barry Song > Signed-off-by: Baoquan He A few nitpicks below: > -void __swap_writepage(struct folio *folio, struct swap_iocb **swap_plug) > -{ > - struct swap_info_struct *sis =3D __swap_entry_to_info(folio->swap= ); > - > - VM_BUG_ON_FOLIO(!folio_test_swapcache(folio), folio); This sanify check is dropped and not added back in anywhere. This is fine, but it might be better to have a similar VM_WARN_ON_FOLIO in swap_writeout? > void swap_read_folio(struct folio *folio, struct swap_iocb **plug) > { > struct swap_info_struct *sis =3D __swap_entry_to_info(folio->swap= ); > @@ -642,13 +664,7 @@ void swap_read_folio(struct folio *folio, struct swa= p_iocb **plug) > /* We have to read from slower devices. Increase zswap protection= . */ > zswap_folio_swapin(folio); > > - if (data_race(sis->flags & SWP_FS_OPS)) { > - swap_read_folio_fs(folio, plug); > - } else if (synchronous) { > - swap_read_folio_bdev_sync(folio, sis); > - } else { > - swap_read_folio_bdev_async(folio, sis); > - } > + sis->ops->read_folio(sis, folio, plug); > > finish: > if (workingset) { > diff --git a/mm/swapfile.c b/mm/swapfile.c > index 4840fd40f36f..8c42632e6765 100644 > --- a/mm/swapfile.c > +++ b/mm/swapfile.c > @@ -3780,6 +3780,15 @@ SYSCALL_DEFINE2(swapon, const char __user *, speci= alfile, int, swap_flags) > goto free_swap_zswap; > } > > + /* > + * init_swap_ops() sets si->ops based on flags. It does not need > + * swapon_mutex, and must complete before enable_swap_info() > + * exposes the device. > + */ > + error =3D init_swap_ops(si); > + if (error) > + goto bad_swap_unlock_inode; I checked the comment above previously and it looked good. But the error label seems not that correct after double check. inode->i_flags will keep the S_SWAPFILE flag. Maybe something like add a inode->i_flags &=3D ~S_SWAPFILE here and goto free_swap_zswap. Sorry I didn't check this part carefully last time. But fortunately, init_swap_ops will never fail at this moment so the issue never triggers. > + > mutex_lock(&swapon_mutex); > prio =3D DEF_SWAP_PRIO; > if (swap_flags & SWAP_FLAG_PREFER) > diff --git a/mm/zswap.c b/mm/zswap.c > index 4b5149173b0e..192401f46de4 100644 > --- a/mm/zswap.c > +++ b/mm/zswap.c > @@ -1054,7 +1054,7 @@ static int zswap_writeback_entry(struct zswap_entry= *entry, > folio_set_reclaim(folio); > > /* start writeback */ > - __swap_writepage(folio, NULL); > + si->ops->write_folio(si, folio, NULL); > > out: > if (ret && ret !=3D -EEXIST) { > -- > 2.52.0 > Rest looks good to me!