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

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Message-ID: <CALTww2-bCOHsK=iXqkTokFBdG=kxc6NsdgtyfWPXBaSX6pmcAA@mail.gmail.com>
Date: Mon, 19 Jan 2026 11:20:03 +0800
From: Xiao Ni <xni@...hat.com>
To: linan666@...weicloud.com
Cc: song@...nel.org, yukuai@...as.com, linux-raid@...r.kernel.org, 
	linux-kernel@...r.kernel.org, yangerkun@...wei.com, yi.zhang@...wei.com
Subject: Re: [PATCH 04/15] md/raid1: use folio for tmppage

On Wed, Dec 17, 2025 at 8:11 PM <linan666@...weicloud.com> wrote:
>
> From: Li Nan <linan122@...wei.com>
>
> Convert tmppage to tmpfolio and use it throughout in raid1.
>
> Signed-off-by: Li Nan <linan122@...wei.com>
> ---
>  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