[dm-devel] simplify I/O size calculation helpers v2

[Christoph Hellwig]

Hi Jens,

this series calculates various I/O size calculations.

Changes since v1:
 - rename chunk_size_left to blk_chunk_sectors_left
 - split a patch into two

Diffstat:
 block/blk-merge.c      |   28 ++++++++++++++++------------
 drivers/md/dm.c        |   18 ++++++------------
 include/linux/blkdev.h |   27 ++++++++-------------------
 3 files changed, 30 insertions(+), 43 deletions(-)