Re: [PATCH RFC -next 03/26] md/md-bitmap: merge md_bitmap_load() into bitmap_operations

[Mariusz Tkaczyk <mariusz.tkaczyk@linux.intel.com>]

On Sat, 10 Aug 2024 10:08:31 +0800
Yu Kuai <yukuai1@huaweicloud.com> wrote:

> From: Yu Kuai <yukuai3@huawei.com>
> 
> So that the implementation won't be exposed, and it'll be possible
> to invent a new bitmap by replacing bitmap_operations.

I don't like repeating same commit message for few patches.

> 
> Signed-off-by: Yu Kuai <yukuai3@huawei.com>
> ---
>  drivers/md/md-bitmap.c |  6 +++---
>  drivers/md/md-bitmap.h | 10 +++++++++-
>  2 files changed, 12 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
> index d731f7d4bbbb..9a9f0fe3ebd0 100644
> --- a/drivers/md/md-bitmap.c
> +++ b/drivers/md/md-bitmap.c
> @@ -1965,7 +1965,7 @@ static struct bitmap *bitmap_create(struct mddev
> *mddev, int slot) return ERR_PTR(err);
>  }
>  
> -int md_bitmap_load(struct mddev *mddev)
> +static int bitmap_load(struct mddev *mddev)
>  {
>  	int err = 0;
>  	sector_t start = 0;
> @@ -2021,7 +2021,6 @@ int md_bitmap_load(struct mddev *mddev)
>  out:
>  	return err;
>  }
> -EXPORT_SYMBOL_GPL(md_bitmap_load);
>  
>  /* caller need to free returned bitmap with md_bitmap_free() */
>  struct bitmap *get_bitmap_from_slot(struct mddev *mddev, int slot)
> @@ -2411,7 +2410,7 @@ location_store(struct mddev *mddev, const char *buf,
> size_t len) }
>  
>  			mddev->bitmap = bitmap;
> -			rv = md_bitmap_load(mddev);
> +			rv = bitmap_load(mddev);
>  			if (rv) {
>  				mddev->bitmap_info.offset = 0;
>  				md_bitmap_destroy(mddev);
> @@ -2710,6 +2709,7 @@ const struct attribute_group md_bitmap_group = {
>  
>  static struct bitmap_operations bitmap_ops = {
>  	.create			= bitmap_create,
> +	.load			= bitmap_load,
>  };
>  
>  void mddev_set_bitmap_ops(struct mddev *mddev)
> diff --git a/drivers/md/md-bitmap.h b/drivers/md/md-bitmap.h
> index a7cbf0c692fc..de7fbe5903dd 100644
> --- a/drivers/md/md-bitmap.h
> +++ b/drivers/md/md-bitmap.h
> @@ -236,6 +236,7 @@ struct bitmap {
>  
>  struct bitmap_operations {
>  	struct bitmap* (*create)(struct mddev *mddev, int slot);
> +	int (*load)(struct mddev *mddev);
>  };
>  
>  /* the bitmap API */
> @@ -250,7 +251,14 @@ static inline struct bitmap *md_bitmap_create(struct
> mddev *mddev, int slot) return mddev->bitmap_ops->create(mddev, slot);
>  }
>  
> -int md_bitmap_load(struct mddev *mddev);
> +static inline int md_bitmap_load(struct mddev *mddev)
> +{
> +	if (!mddev->bitmap_ops->load)
> +		return -EOPNOTSUPP;
> +
> +	return mddev->bitmap_ops->load(mddev);
> +}

At this point we have only on bitmpa op (at that probably won't change), so if
we we have bitmap_ops assigned (mddev->bitmap_ops != NULL) then ->load is must
have, hence I don't see a need for this wrapper.

you probably made this to avoid changes across code. If yes, please mention it
in commit message but I still would prefer to replace them all by calls to
mddev->bitmap_ops->load().

Mariusz