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

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Message-ID: <e6f77ede-444b-4d5c-9353-b18f84376ee7@redhat.com>
Date: Tue, 20 Jan 2026 11:38:50 +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


在 2026/1/19 11:20, Xiao Ni 写道:
> 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


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