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charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Thu, May 14, 2026 at 10:06=E2=80=AFAM Baoquan He = wrote: > > On 05/13/26 at 01:53am, Kairui Song wrote: > > On Tue, May 12, 2026 at 6:50=E2=80=AFPM Baoquan He wrote: > > > > > > This simplifies codes and makes logic clearer. And also makes later a= ny > > > 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 > > Will fix, thanks. > > > > > > > > > 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_p= lug) > > > -{ > > > - 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? > > Good catch. In the old code, it's called by both swap_writeout() and > zswap_writeback_entry(). In zswap_writeback_entry(), the folio is > allocated in-place, we don't need to worry about it now. I am fine to > add it back in swap_writeout() because adding it inside all three > swap_write_xxx() is a little too much. > > Cscope tag: __swap_writepage > # line filename / context / line > 1 288 /home/bhe/code/linux/mm/page_io.c <> > __swap_writepage(folio, swap_plug); > 2 1053 /home/bhe/code/linux/mm/zswap.c <> > __swap_writepage(folio, NULL); > > > > > > 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= swap_iocb **plug) > > > /* We have to read from slower devices. Increase zswap protec= tion. */ > > > 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 *, s= pecialfile, int, swap_flags) > > > goto free_swap_zswap; > > > } > > > > > > + /* > > > + * init_swap_ops() sets si->ops based on flags. It does not n= eed > > > + * 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. > > Right. How about moving it zswap_swapon() because it only relies on > si->flags setting currently? You mean before zswap_swapon()? Then that sounds good to me.