Re: [PATCH 03/15] md: use folio for bb_folio

在 2026/1/19 11:03, Xiao Ni 写道:
> On Wed, Dec 17, 2025 at 8:11 PM <[email protected]> wrote:
>>
>> From: Li Nan <[email protected]>
>>
>> Convert bio_page to bio_folio and use it throughout.
>>
>> Signed-off-by: Li Nan <[email protected]>
>> ---
>>   drivers/md/md.h |  3 ++-
>>   drivers/md/md.c | 25 +++++++++++++------------
>>   2 files changed, 15 insertions(+), 13 deletions(-)
>>
>> diff --git a/drivers/md/md.h b/drivers/md/md.h
>> index 410f8a6b75e7..aa6d9df50fd0 100644
>> --- a/drivers/md/md.h
>> +++ b/drivers/md/md.h
>> @@ -144,7 +144,8 @@ struct md_rdev {
>>          struct block_device *bdev;      /* block device handle */
>>          struct file *bdev_file;         /* Handle from open for bdev */
>>
>> -       struct page     *sb_page, *bb_page;
>> +       struct page     *sb_page;
>> +       struct folio    *bb_folio;
>>          int             sb_loaded;
>>          __u64           sb_events;
>>          sector_t        data_offset;    /* start of data in array */
>> diff --git a/drivers/md/md.c b/drivers/md/md.c
>> index 9dfd6f8da5b8..0732bbcdb95d 100644
>> --- a/drivers/md/md.c
>> +++ b/drivers/md/md.c
>> @@ -1073,9 +1073,9 @@ void md_rdev_clear(struct md_rdev *rdev)
>>                  rdev->sb_start = 0;
>>                  rdev->sectors = 0;
>>          }
>> -       if (rdev->bb_page) {
>> -               put_page(rdev->bb_page);
>> -               rdev->bb_page = NULL;
>> +       if (rdev->bb_folio) {
>> +               folio_put(rdev->bb_folio);
>> +               rdev->bb_folio = NULL;
>>          }
>>          badblocks_exit(&rdev->badblocks);
>>   }
>> @@ -1909,9 +1909,10 @@ static int super_1_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor_
>>
>>          rdev->desc_nr = le32_to_cpu(sb->dev_number);
>>
>> -       if (!rdev->bb_page) {
>> -               rdev->bb_page = alloc_page(GFP_KERNEL);
>> -               if (!rdev->bb_page)
>> +       if (!rdev->bb_folio) {
>> +               rdev->bb_folio = folio_alloc(GFP_KERNEL, 0);
>> +
>> +               if (!rdev->bb_folio)
>>                          return -ENOMEM;
>>          }
>>          if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_BAD_BLOCKS) &&
>> @@ -1930,10 +1931,10 @@ static int super_1_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor_
>>                  if (offset == 0)
>>                          return -EINVAL;
>>                  bb_sector = (long long)offset;
>> -               if (!sync_page_io(rdev, bb_sector, sectors << 9,
>> -                                 rdev->bb_page, REQ_OP_READ, true))
>> +               if (!sync_folio_io(rdev, bb_sector, sectors << 9, 0,
>> +                                 rdev->bb_folio, REQ_OP_READ, true))
>>                          return -EIO;
>> -               bbp = (__le64 *)page_address(rdev->bb_page);
>> +               bbp = (__le64 *)folio_address(rdev->bb_folio);
>>                  rdev->badblocks.shift = sb->bblog_shift;
>>                  for (i = 0 ; i < (sectors << (9-3)) ; i++, bbp++) {
>>                          u64 bb = le64_to_cpu(*bbp);
>> @@ -2300,7 +2301,7 @@ static void super_1_sync(struct mddev *mddev, struct md_rdev *rdev)
>>                  md_error(mddev, rdev);
>>          else {
>>                  struct badblocks *bb = &rdev->badblocks;
>> -               __le64 *bbp = (__le64 *)page_address(rdev->bb_page);
>> +               __le64 *bbp = (__le64 *)folio_address(rdev->bb_folio);
>>                  u64 *p = bb->page;
>>                  sb->feature_map |= cpu_to_le32(MD_FEATURE_BAD_BLOCKS);
>>                  if (bb->changed) {
>> @@ -2953,7 +2954,7 @@ void md_update_sb(struct mddev *mddev, int force_change)
>>                                  md_write_metadata(mddev, rdev,
>>                                                    rdev->badblocks.sector,
>>                                                    rdev->badblocks.size << 9,
>> -                                                 rdev->bb_page, 0);
>> +                                                 folio_page(rdev->bb_folio, 0), 0);
>>                                  rdev->badblocks.size = 0;
>>                          }
>>
>> @@ -3809,7 +3810,7 @@ int md_rdev_init(struct md_rdev *rdev)
>>          rdev->sb_events = 0;
>>          rdev->last_read_error = 0;
>>          rdev->sb_loaded = 0;
>> -       rdev->bb_page = NULL;
>> +       rdev->bb_folio = NULL;
>>          atomic_set(&rdev->nr_pending, 0);
>>          atomic_set(&rdev->read_errors, 0);
>>          atomic_set(&rdev->corrected_errors, 0);
>> --
>> 2.39.2
>>
> 
> Hi Nan
> 
> Bad block page is only one single page. I don't think it's necessary
> to use folio here. And it uses folio_page to get the page again. Or do
> you plan to replace all page apis to folio apis? Looking through all
> patches, sync_page_io is not removed. In patch02, it says sync_page_io
> will be removed. So maybe it's better to switch bb_page to bb_folio in
> your second patch set? And this patch set only focuses on replacing
> sync pages with folio. It's my 2 cents point. If you think it's better
> to change the bad block page here, I'm still ok.
> 
> Best Regards
> Xiao
> 

Hi Xiao,

Thanks for your review. Move it to next patch set is fine. I will delete
this patch in v2.

-- 
Thanks,
Nan