linux-kernel - Re: [PATCH -next v3 6/7] md: factor out a helper rdev_addable() from remove_and_add

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Message-ID: <CAPhsuW74MEFjNTNErYfOT1gX+BUdbDwaV1oTmmcz=_76Ym3ZuA@mail.gmail.com>
Date:   Mon, 21 Aug 2023 16:22:31 -0700
From:   Song Liu <song@...nel.org>
To:     Yu Kuai <yukuai1@...weicloud.com>
Cc:     xni@...hat.com, mariusz.tkaczyk@...ux.intel.com,
        linux-raid@...r.kernel.org, linux-kernel@...r.kernel.org,
        yukuai3@...wei.com, yi.zhang@...wei.com, yangerkun@...wei.com
Subject: Re: [PATCH -next v3 6/7] md: factor out a helper rdev_addable() from remove_and_add_spares()

On Sun, Aug 20, 2023 at 2:13 AM Yu Kuai <yukuai1@...weicloud.com> wrote:
>
> From: Yu Kuai <yukuai3@...wei.com>
>
> There are no functional changes, just to make the code simpler and
> prepare to delay remove_and_add_spares() to md_start_sync().
>
> Signed-off-by: Yu Kuai <yukuai3@...wei.com>
> ---
>  drivers/md/md.c | 28 ++++++++++++++++------------
>  1 file changed, 16 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index 11d27c934fdd..cdc361c521d4 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -9177,6 +9177,20 @@ static bool rdev_is_spare(struct md_rdev *rdev)
>                !test_bit(Faulty, &rdev->flags);
>  }
>
> +static bool rdev_addable(struct md_rdev *rdev)
> +{
> +       if (test_bit(Candidate, &rdev->flags) || rdev->raid_disk >= 0 ||
> +           test_bit(Faulty, &rdev->flags))
> +               return false;
> +
> +       if (!test_bit(Journal, &rdev->flags) && !md_is_rdwr(rdev->mddev) &&

Instead of straightforward refactoring, I hope we can make these rdev_*
helpers more meaningful, and hopefullly reusable. For example, let's define
the meaning of "addable", and write the function to match that meaning. In
this case, I think we shouldn't check md_is_rdwr() inside rdev_addable().

Does this make sense?

Thanks,
Song


> +           !(rdev->saved_raid_disk >= 0 &&
> +             !test_bit(Bitmap_sync, &rdev->flags)))
> +               return false;
> +
> +       return true;
> +}
> +
>  static int remove_and_add_spares(struct mddev *mddev,
>                                  struct md_rdev *this)
>  {
> @@ -9227,20 +9241,10 @@ static int remove_and_add_spares(struct mddev *mddev,
>                         continue;
>                 if (rdev_is_spare(rdev))
>                         spares++;
> -               if (test_bit(Candidate, &rdev->flags))
> +               if (!rdev_addable(rdev))
>                         continue;
> -               if (rdev->raid_disk >= 0)
> -                       continue;
> -               if (test_bit(Faulty, &rdev->flags))
> -                       continue;
> -               if (!test_bit(Journal, &rdev->flags)) {
> -                       if (!md_is_rdwr(mddev) &&
> -                           !(rdev->saved_raid_disk >= 0 &&
> -                             !test_bit(Bitmap_sync, &rdev->flags)))
> -                               continue;
> -
> +               if (!test_bit(Journal, &rdev->flags))
>                         rdev->recovery_offset = 0;
> -               }
>                 if (mddev->pers->hot_add_disk(mddev, rdev) == 0) {
>                         /* failure here is OK */
>                         sysfs_link_rdev(mddev, rdev);
> --
> 2.39.2
>