[PATCH for-next v12 00/12] Fixed-buffer for uring-cmd/passthru

[Anuj Gupta]

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.
Patches 3 - 5 carve out a block helper and scsi, nvme then use it to
avoid duplication of code.
Patch 6 and 7 contains a bunch of general nvme cleanups, which got added
along the iterations.


Using registered-buffers showed ~20% IOPS hike from 2.62M to 3.17M in my setup
Without fixedbufs
*****************
# taskset -c 0 t/io_uring -b512 -d128 -c32 -s32 -p1 -F1 -B0 -O0 -n1 -u1 /dev/ng0n1
submitter=0, tid=3623, 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=2.62M, BW=1281MiB/s, IOS/call=32/31
IOPS=2.62M, BW=1277MiB/s, IOS/call=32/32
IOPS=2.62M, BW=1277MiB/s, IOS/call=32/32
IOPS=2.61M, BW=1276MiB/s, IOS/call=32/32
^CExiting on signal
Maximum IOPS=2.62M


With fixedbufs
**************
# taskset -c 0 t/io_uring -b512 -d128 -c32 -s32 -p1 -F1 -B1 -O0 -n1 -u1 /dev/ng0n1
submitter=0, tid=3627, 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=3.17M, BW=1546MiB/s, IOS/call=32/31
IOPS=3.17M, BW=1546MiB/s, IOS/call=32/31
IOPS=3.17M, BW=1546MiB/s, IOS/call=32/32
IOPS=3.16M, BW=1544MiB/s, IOS/call=32/32
^CExiting on signal
Maximum IOPS=3.17M


Changes since v11:

Patch 2 - Add a check for flags (Jens)
Patch 3 - Moved the refactoring patches to start, before the nvme-refactoring
patches (Christoph)
Patch 3 - Initialize ret to 0, to prevent uninitialized variable warning
(kernel test robot)
Patch 4 - Added the onstack advantage part in the commit description (Christoph)
Patch 7 - Move blk_rq_free_request into nvme_map_user_request to handle error
scenarios, instead of doing it using goto in it's callers, helps in getting
rid of a uninitialized variable warning (kernel test robot)
Patch 10 - Folded it in with the next patch to avoid compiler warning for
unused static functions(Christoph)

Changes since v10:
- Patch 3: Fix overly long line (Christoph)
- Patch 4: create a helper in block-map for vectored and non-vectored-io, to be used by scsi and nvme (Christoph)
- Patch 5: Rename bio_map_get to blk_rq_map_bio_alloc and bio_map_put to blk_mq_map_bio_put (Christoph)
- Patch 6: Split it into a prep patch and avoid duplicate checks (Christoph)
- Patch 7: Put changes to pass ubuffer as a integer in a separate prep patch and simplify condition checks in nvme (Christoph)

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 (6):
  io_uring: add io_uring_cmd_import_fixed
  io_uring: introduce fixed buffer support for io_uring_cmd
  block: add blk_rq_map_user_io
  scsi: Use blk_rq_map_user_io helper
  nvme: Use blk_rq_map_user_io helper
  block: rename bio_map_put to blk_mq_map_bio_put

Kanchan Joshi (6):
  nvme: refactor nvme_add_user_metadata
  nvme: refactor nvme_alloc_request
  block: factor out blk_rq_map_bio_alloc helper
  block: extend functionality to map bvec iterator
  nvme: pass ubuffer as an integer
  nvme: wire up fixed buffer support for nvme passthrough

 block/blk-map.c               | 150 ++++++++++++++++++++++++++++++----
 drivers/nvme/host/ioctl.c     | 144 ++++++++++++++++++--------------
 drivers/scsi/scsi_ioctl.c     |  22 +----
 drivers/scsi/sg.c             |  22 +----
 include/linux/blk-mq.h        |   2 +
 include/linux/io_uring.h      |  10 ++-
 include/uapi/linux/io_uring.h |   9 ++
 io_uring/uring_cmd.c          |  28 ++++++-
 8 files changed, 266 insertions(+), 121 deletions(-)

-- 
2.25.1