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

[Yu Kuai <yukuai1@xxxxxxxxxxxxxxx>]

Hi,

在 2024/08/13 15:07, Mariusz Tkaczyk 写道:
> On Sat, 10 Aug 2024 10:08:31 +0800
> Yu Kuai <yukuai1@xxxxxxxxxxxxxxx> wrote:
>
> > From: Yu Kuai <yukuai3@xxxxxxxxxx>
> >
> > 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@xxxxxxxxxx>
> > ---
> >   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.

Yes, we must define the load op otherwise the bitmap_ops is meaningless.

> 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().

I'll replace to use mddev->bitmap_ops->load() directly, and other
places. And I'll keep this inline helper for some ops that is used for
md-cluster, because I'm not planning to support md-cluster for the new
bitmap first.

Thanks,
Kuai

> Mariusz
>
>
> .