[PATCH for-next v10 0/7] Fixed-buffer for uring-cmd/passthru

[Kanchan Joshi]

Hi

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.
Patch 3 and 4 contains a bunch of general nvme cleanups, which got added
along the iterations.

Using registered-buffers showed IOPS hike from 1.65M to 2.04M.
Without fixedbufs
*****************
# taskset -c 0 t/io_uring -b512 -d128 -c32 -s32 -p1 -F1 -B0 -O0 -n1 -u1 /dev/ng0n1
submitter=0, tid=2178, file=/dev/ng0n1, node=-1
polled=1, fixedbufs=0/0, register_files=1, buffered=1, QD=128
Engine=io_uring, sq_ring=128, cq_ring=128
IOPS=1.63M, BW=796MiB/s, IOS/call=32/31
IOPS=1.64M, BW=800MiB/s, IOS/call=32/32
IOPS=1.64M, BW=801MiB/s, IOS/call=32/32
IOPS=1.65M, BW=803MiB/s, IOS/call=32/31
^CExiting on signal
Maximum IOPS=1.65M

With fixedbufs
**************
# taskset -c 0 t/io_uring -b512 -d128 -c32 -s32 -p1 -F1 -B1 -O0 -n1 -u1 /dev/ng0n1
submitter=0, tid=2180, file=/dev/ng0n1, node=-1
polled=1, fixedbufs=1/0, register_files=1, buffered=1, QD=128
Engine=io_uring, sq_ring=128, cq_ring=128
IOPS=2.03M, BW=991MiB/s, IOS/call=32/31
IOPS=2.04M, BW=998MiB/s, IOS/call=32/32
IOPS=2.04M, BW=997MiB/s, IOS/call=32/31
^CExiting on signal
Maximum IOPS=2.04M

Changes since v9:
- Patch 6: Make blk_rq_map_user_iov() to operate on bvec iterator
  (Christoph)
- Patch 7: Change nvme to use the above

Changes since v8:
- Split some patches further; now 7 patches rather than 5 (Christoph)
- Applied a bunch of other suggested cleanups (Christoph)

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 (5):
  nvme: refactor nvme_add_user_metadata
  nvme: refactor nvme_alloc_request
  block: factor out bio_map_get helper
  block: extend functionality to map bvec iterator
  nvme: wire up fixed buffer support for nvme passthrough

 block/blk-map.c               | 108 ++++++++++++++++++++---
 drivers/nvme/host/ioctl.c     | 160 ++++++++++++++++++++--------------
 include/linux/io_uring.h      |  10 ++-
 include/uapi/linux/io_uring.h |   9 ++
 io_uring/uring_cmd.c          |  26 +++++-
 5 files changed, 237 insertions(+), 76 deletions(-)

-- 
2.25.1