On 2021-02-01 12:16 a.m., Kashyap Desai wrote:

This patch series is to support io_uring iopoll feature
in scsi stack. This patch set requires shared hosttag support.

This patch set is created on top of 5.12/scsi-staging branch.
https://kernel.googlesource.com/pub/scm/linux/kernel/git/mkp/scsi/+/refs/heads/5.12/scsi-staging

Hi,
I don't understand how this patchset works. My testing shows
scsi_debug is broken and I will be sending a correcting patch
shortly (similar to the one I sent you on 20210108).

The scsi_debug driver is a simplified LLD that needs to know in
advance whether a request/command issued to it will be using the
.mq_poll callback. Perhaps you have found another way but one
simple way to find that out is this test:
    if (request->cmd_flags & REQ_HIPRI)

In the case of scsi_debug (after my patch) the delay associated with
the command is not wired up to generate an event which leads to
completion. Instead, callbacks through .mq_poll are expected and
they will check if that delay has expired, if not the callback returns
0. When the delay has expired and a .mq_poll is received then completion
occurs.

Doug Gilbert

v3 ->
- added reviewed-by tag
- Fix comment provided by Hannes for below patch.
https://patchwork.kernel.org/project/linux-scsi/patch/20201203034100.29716-3-kashyap.desai@broadcom.com/
- Fix Functional issue of poll_queues settings not working in v2.

v2 ->
- updated feedback from v1.
- added reviewed-by & tested-by tag
- remove flood of prints in scsi_debug driver during iopoll
   reported by Douglas Gilbert.
- added new patch to support to get shost from hctx.
   added new helper function "scsi_init_hctx"

v1 ->
Fixed warnings in scsi_debug driver.
Reported-by: kernel test robot <redacted>

Kashyap Desai (4):
   add io_uring with IOPOLL support in scsi layer
   megaraid_sas: iouring iopoll support
   scsi_debug : iouring iopoll support
   scsi: set shost as hctx driver_data

  drivers/scsi/megaraid/megaraid_sas.h        |   3 +
  drivers/scsi/megaraid/megaraid_sas_base.c   |  87 +++++++++++--
  drivers/scsi/megaraid/megaraid_sas_fusion.c |  42 ++++++-
  drivers/scsi/megaraid/megaraid_sas_fusion.h |   2 +
  drivers/scsi/scsi_debug.c                   | 130 ++++++++++++++++++++
  drivers/scsi/scsi_lib.c                     |  29 ++++-
  include/scsi/scsi_cmnd.h                    |   1 +
  include/scsi/scsi_host.h                    |  11 ++
  8 files changed, 291 insertions(+), 14 deletions(-)


base-commit: a927ec3995427e9c47752900ad2df0755d02aba5