Commit 62f26317 authored by Jeffle Xu's avatar Jeffle Xu Committed by Mike Snitzer
Browse files

dm: cleanup of front padding calculation 



Add two helper macros calculating the offset of bio in struct dm_io and
struct dm_target_io respectively.

Besides, simplify the front padding calculation in
dm_alloc_md_mempools().

Signed-off-by: default avatarJeffle Xu <jefflexu@linux.alibaba.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 23c4ecbc

drivers/md/dm.c

+10 −6
Original line number Diff line number Diff line
@@ -105,12 +105,16 @@ struct dm_io { 
	struct dm_target_io tio;

};



#define DM_TARGET_IO_BIO_OFFSET (offsetof(struct dm_target_io, clone))

#define DM_IO_BIO_OFFSET \

	(offsetof(struct dm_target_io, clone) + offsetof(struct dm_io, tio))



void *dm_per_bio_data(struct bio *bio, size_t data_size)

{

	struct dm_target_io *tio = container_of(bio, struct dm_target_io, clone);

	if (!tio->inside_dm_io)

		return (char *)bio - offsetof(struct dm_target_io, clone) - data_size;

	return (char *)bio - offsetof(struct dm_target_io, clone) - offsetof(struct dm_io, tio) - data_size;

		return (char *)bio - DM_TARGET_IO_BIO_OFFSET - data_size;

	return (char *)bio - DM_IO_BIO_OFFSET - data_size;

}

EXPORT_SYMBOL_GPL(dm_per_bio_data);
@@ -118,9 +122,9 @@ struct bio *dm_bio_from_per_bio_data(void *data, size_t data_size) 
{

	struct dm_io *io = (struct dm_io *)((char *)data + data_size);

	if (io->magic == DM_IO_MAGIC)

		return (struct bio *)((char *)io + offsetof(struct dm_io, tio) + offsetof(struct dm_target_io, clone));

		return (struct bio *)((char *)io + DM_IO_BIO_OFFSET);

	BUG_ON(io->magic != DM_TIO_MAGIC);

	return (struct bio *)((char *)io + offsetof(struct dm_target_io, clone));

	return (struct bio *)((char *)io + DM_TARGET_IO_BIO_OFFSET);

}

EXPORT_SYMBOL_GPL(dm_bio_from_per_bio_data);
@@ -2849,8 +2853,8 @@ struct dm_md_mempools *dm_alloc_md_mempools(struct mapped_device *md, enum dm_qu 
	case DM_TYPE_BIO_BASED:

	case DM_TYPE_DAX_BIO_BASED:

		pool_size = max(dm_get_reserved_bio_based_ios(), min_pool_size);

		front_pad = roundup(per_io_data_size, __alignof__(struct dm_target_io)) + offsetof(struct dm_target_io, clone);

		io_front_pad = roundup(front_pad,  __alignof__(struct dm_io)) + offsetof(struct dm_io, tio);

		front_pad = roundup(per_io_data_size, __alignof__(struct dm_target_io)) + DM_TARGET_IO_BIO_OFFSET;

		io_front_pad = roundup(per_io_data_size,  __alignof__(struct dm_io)) + DM_IO_BIO_OFFSET;

		ret = bioset_init(&pools->io_bs, pool_size, io_front_pad, 0);

		if (ret)

			goto out;