[PATCH 0/5] block: another block copy offload

[Keith Busch]

From: Keith Busch <kbusch at kernel.org>

I was never happy with previous block copy offload attempts, so I had to
take a stab at it. And I was recently asked to take a look at this, so
here goes.

Some key implementation differences from previous approaches:

  1. Only one bio is needed to describe a copy request, so no plugging
     or dispatch tricks required. Like read and write requests, these
     can be artbitrarily large and will be split as needed based on the
     request_queue's limits. The bio's are mergeable with other copy
     commands on adjacent destination sectors.

  2. You can describe as many source sectors as you want in a vector in
     a single bio. This aligns with the nvme protocol's Copy implementation,
     which can be used to efficiently defragment scattered blocks into a
     contiguous destination with a single command.

Oh, and the nvme-target support was included with this patchset too, so
there's a purely in-kernel way to test out the code paths if you don't
have otherwise capable hardware. I also used qemu since that nvme device
supports copy offload too.

Keith Busch (5):
  block: new sector copy api
  block: add support for copy offload
  nvme: add support for copy offload
  block: add support for vectored copies
  nvmet: implement copy support for bdev backed target

 block/bio.c                       |  25 +++++++
 block/blk-core.c                  |   4 ++
 block/blk-lib.c                   | 115 ++++++++++++++++++++++++++++++
 block/blk-merge.c                 |  28 +++++++-
 block/blk-sysfs.c                 |   9 +++
 block/blk.h                       |  17 ++++-
 block/ioctl.c                     |  89 +++++++++++++++++++++++
 drivers/nvme/host/core.c          |  61 ++++++++++++++++
 drivers/nvme/target/io-cmd-bdev.c |  52 ++++++++++++++
 include/linux/bio.h               |  20 ++++++
 include/linux/blk-mq.h            |   5 ++
 include/linux/blk_types.h         |   2 +
 include/linux/blkdev.h            |  18 +++++
 include/linux/bvec.h              |  68 +++++++++++++++++-
 include/linux/nvme.h              |  42 ++++++++++-
 include/uapi/linux/fs.h           |  17 +++++
 16 files changed, 566 insertions(+), 6 deletions(-)

-- 
2.47.1