[PATCH for-next v8 0/5] fixed-buffer for uring-cmd/passthru

[Kanchan Joshi <joshi.k@samsung.com>]

Currently uring-cmd lacks the ability to leverage the pre-registered
buffers. This series adds that support in uring-cmd, and plumbs
nvme passthrough to work with it.

Using registered-buffers showed IOPS hike from 1.9M to 2.2M in my tests.

Patch 1, 3, 4 = prep
Patch 2 = expand io_uring command to use registered-buffers
Patch 5 = expand nvme passthrough to use registered-buffers

Changes since v7:
- Patch 3: added many cleanups/refactoring suggested by Christoph
- Patch 4: added copying-pages fallback for bounce-buffer/dma-alignment case
  (Christoph)

Changes since v6:
- Patch 1: fix warning for io_uring_cmd_import_fixed (robot)
-
Changes since v5:
- Patch 4: newly addd, to split a nvme function into two
- Patch 3: folded cleanups in bio_map_user_iov (Chaitanya, Pankaj)
- Rebase to latest for-next

Changes since v4:
- Patch 1, 2: folded all review comments of Jens

Changes since v3:
- uring_cmd_flags, change from u16 to u32 (Jens)
- patch 3, add another helper to reduce code-duplication (Jens)

Changes since v2:
- Kill the new opcode, add a flag instead (Pavel)
- Fix standalone build issue with patch 1 (Pavel)

Changes since v1:
- Fix a naming issue for an exported helper

Anuj Gupta (2):
  io_uring: add io_uring_cmd_import_fixed
  io_uring: introduce fixed buffer support for io_uring_cmd

Kanchan Joshi (3):
  nvme: refactor nvme_alloc_user_request
  block: add helper to map bvec iterator for passthrough
  nvme: wire up fixed buffer support for nvme passthrough

 block/blk-map.c               | 111 +++++++++++++++++++++++---
 drivers/nvme/host/ioctl.c     | 141 ++++++++++++++++++++--------------
 include/linux/blk-mq.h        |   1 +
 include/linux/io_uring.h      |  10 ++-
 include/uapi/linux/io_uring.h |   9 +++
 io_uring/uring_cmd.c          |  26 ++++++-
 6 files changed, 230 insertions(+), 68 deletions(-)

-- 
2.25.1