Re: [PATCH 04/15] md/raid1: use folio for tmppage

[Xiao Ni]

在 2026/1/19 11:20, Xiao Ni 写道:
> On Wed, Dec 17, 2025 at 8:11 PM <linan666@xxxxxxxxxxxxxxx> wrote:
> > From: Li Nan <linan122@xxxxxxxxxx>
> >
> > Convert tmppage to tmpfolio and use it throughout in raid1.
> >
> > Signed-off-by: Li Nan <linan122@xxxxxxxxxx>
> > ---
> >   drivers/md/raid1.h |  2 +-
> >   drivers/md/raid1.c | 18 ++++++++++--------
> >   2 files changed, 11 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/md/raid1.h b/drivers/md/raid1.h
> > index c98d43a7ae99..d480b3a8c2c4 100644
> > --- a/drivers/md/raid1.h
> > +++ b/drivers/md/raid1.h
> > @@ -101,7 +101,7 @@ struct r1conf {
> >          /* temporary buffer to synchronous IO when attempting to repair
> >           * a read error.
> >           */
> > -       struct page             *tmppage;
> > +       struct folio            *tmpfolio;
> >
> >          /* When taking over an array from a different personality, we store
> >           * the new thread here until we fully activate the array.
> > diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
> > index 407925951299..43453f1a04f4 100644
> > --- a/drivers/md/raid1.c
> > +++ b/drivers/md/raid1.c
> > @@ -2417,8 +2417,8 @@ static void fix_read_error(struct r1conf *conf, struct r1bio *r1_bio)
> >                                rdev->recovery_offset >= sect + s)) &&
> >                              rdev_has_badblock(rdev, sect, s) == 0) {
> >                                  atomic_inc(&rdev->nr_pending);
> > -                               if (sync_page_io(rdev, sect, s<<9,
> > -                                        conf->tmppage, REQ_OP_READ, false))
> > +                               if (sync_folio_io(rdev, sect, s<<9, 0,
> > +                                        conf->tmpfolio, REQ_OP_READ, false))
> >                                          success = 1;
> >                                  rdev_dec_pending(rdev, mddev);
> >                                  if (success)
> > @@ -2447,7 +2447,8 @@ static void fix_read_error(struct r1conf *conf, struct r1bio *r1_bio)
> >                              !test_bit(Faulty, &rdev->flags)) {
> >                                  atomic_inc(&rdev->nr_pending);
> >                                  r1_sync_page_io(rdev, sect, s,
> > -                                               conf->tmppage, REQ_OP_WRITE);
> > +                                               folio_page(conf->tmpfolio, 0),
> > +                                               REQ_OP_WRITE);
> >                                  rdev_dec_pending(rdev, mddev);
> >                          }
> >                  }
> > @@ -2461,7 +2462,8 @@ static void fix_read_error(struct r1conf *conf, struct r1bio *r1_bio)
> >                              !test_bit(Faulty, &rdev->flags)) {
> >                                  atomic_inc(&rdev->nr_pending);
> >                                  if (r1_sync_page_io(rdev, sect, s,
> > -                                               conf->tmppage, REQ_OP_READ)) {
> > +                                               folio_page(conf->tmpfolio, 0),
> > +                                               REQ_OP_READ)) {
> >                                          atomic_add(s, &rdev->corrected_errors);
> >                                          pr_info("md/raid1:%s: read error corrected (%d sectors at %llu on %pg)\n",
> >                                                  mdname(mddev), s,
> > @@ -3120,8 +3122,8 @@ static struct r1conf *setup_conf(struct mddev *mddev)
> >          if (!conf->mirrors)
> >                  goto abort;
> >
> > -       conf->tmppage = alloc_page(GFP_KERNEL);
> > -       if (!conf->tmppage)
> > +       conf->tmpfolio = folio_alloc(GFP_KERNEL, 0);
> > +       if (!conf->tmpfolio)
> >                  goto abort;
> >
> >          r1bio_size = offsetof(struct r1bio, bios[mddev->raid_disks * 2]);
> > @@ -3196,7 +3198,7 @@ static struct r1conf *setup_conf(struct mddev *mddev)
> >          if (conf) {
> >                  mempool_destroy(conf->r1bio_pool);
> >                  kfree(conf->mirrors);
> > -               safe_put_page(conf->tmppage);
> > +               folio_put(conf->tmpfolio);
> >                  kfree(conf->nr_pending);
> >                  kfree(conf->nr_waiting);
> >                  kfree(conf->nr_queued);
> > @@ -3310,7 +3312,7 @@ static void raid1_free(struct mddev *mddev, void *priv)
> >
> >          mempool_destroy(conf->r1bio_pool);
> >          kfree(conf->mirrors);
> > -       safe_put_page(conf->tmppage);
> > +       folio_put(conf->tmpfolio);
> >          kfree(conf->nr_pending);
> >          kfree(conf->nr_waiting);
> >          kfree(conf->nr_queued);
> > --
> > 2.39.2
> Hi Nan
>
> Same question for patch04 and patch05, tmpage is used in read io path.
>  From the cover letter, this patch set wants to resolve the multi pages
> in sync io path. Is it better to keep them for your future patch set?
>
> Best Regards
> Xiao
>
> Xiao


After reading patch06, I understand here. r1_sync_page_io needs to 
change to r1_sync_folio_io to handle sync read error. Please ignore my 
above comments. patch04 and patch05 look good to me.

Best Regards

Xiao