[PATCH v2 0/5] md: use bio_clone_fast()

[Ming Lei]

Hi,

This patches replaces bio_clone() with bio_fast_clone() in
bio_clone_mddev() because:

1) bio_clone_mddev() is used in raid normal I/O and isn't in
resync I/O path, and all the direct access to bvec table in
raid happens on resync I/O only except for write behind of raid1.
Write behind is treated specially, so the replacement is safe.

2) for write behind, bio_clone() is kept, but this patchset
introduces bio_clone_bioset_partial() to just clone one specific 
bvecs range instead of whole table. Then write behind is improved
too.

V2:
	1) move 3rd patch into 2nd one
	2) kill  bio_clone_mddev() and use  bio_clone_fast() directly
	3) define local variable 'offset' as sector_t in raid1_write_request()

V1:
	1) don't introduce bio_clone_slow_mddev_partial()
	2) return failure if mddev->bio_set can't be created
	3) remove check in bio_clone_mddev() as suggested by
	Christoph Hellwig.
	4) rename bio_clone_mddev() as bio_clone_fast_mddev()

Ming Lei (5):
  block: introduce bio_clone_bioset_partial()
  md: fail if mddev->bio_set can't be created
  md/raid1: use bio_clone_bioset_partial() in case of write behind
  md: remove unnecessary check on mddev
  md: fast clone bio in bio_clone_mddev()

 block/bio.c         | 61 +++++++++++++++++++++++++++++++++++++++++------------
 drivers/md/faulty.c |  2 +-
 drivers/md/md.c     | 15 ++++---------
 drivers/md/md.h     |  2 --
 drivers/md/raid1.c  | 28 +++++++++++++++++-------
 drivers/md/raid10.c | 11 +++++-----
 drivers/md/raid5.c  |  4 ++--
 include/linux/bio.h | 11 ++++++++--
 8 files changed, 89 insertions(+), 45 deletions(-)

-- 
2.7.4