[PATCH v5 00/21] ibmvfc: initial MQ development/enablement

[Tyrel Datwyler]

Recent updates in pHyp Firmware and VIOS releases provide new infrastructure
towards enabling Subordinate Command Response Queues (Sub-CRQs) such that each
Sub-CRQ is a channel backed by an actual hardware queue in the FC stack on the
partner VIOS. Sub-CRQs are registered with the firmware via hypercalls and then
negotiated with the VIOS via new Management Datagrams (MADs) for channel setup.

This initial implementation adds the necessary Sub-CRQ framework and implements
the new MADs for negotiating and assigning a set of Sub-CRQs to associated VIOS
HW backed channels.

This latest series is completely rebased and reimplemented on top of the recent
("ibmvfc: MQ prepartory locking work") series. [1]

[1] https://lore.kernel.org/linux-scsi/20210106201835.1053593-1-tyreld@linux.ibm.com/

changes in v5:
* Addressed comments from brking in following patches:
* Patch 18: Drop queue lock in loop after sending cancel event
	    Remove cancel event from list after completion
	    Return -EIO on unknown failure
* Patch 21: Removed can_queue rebase artifact and range check user supplied
            nr_scsi_hw_queue value

changes in v4:
* Series rebased and reworked on top of previous ibmvfc locking series
* Dropped all previous Reviewed-by tags

changes in v3:
* Patch 4: changed firmware support logging to dev_warn_once
* Patch 6: adjusted locking
* Patch 15: dropped logging verbosity, moved cancel event tracking into subqueue
* Patch 17: removed write permission for migration module parameters
	    drive hard reset after update to num of scsi channels

changes in v2:
* Patch 4: NULL'd scsi_scrq reference after deallocation
* Patch 6: Added switch case to handle XPORT event
* Patch 9: fixed ibmvfc_event leak and double free
* added support for cancel command with MQ
* added parameter toggles for MQ settings

Tyrel Datwyler (21):
  ibmvfc: add vhost fields and defaults for MQ enablement
  ibmvfc: move event pool init/free routines
  ibmvfc: init/free event pool during queue allocation/free
  ibmvfc: add size parameter to ibmvfc_init_event_pool
  ibmvfc: define hcall wrapper for registering a Sub-CRQ
  ibmvfc: add Subordinate CRQ definitions
  ibmvfc: add alloc/dealloc routines for SCSI Sub-CRQ Channels
  ibmvfc: add Sub-CRQ IRQ enable/disable routine
  ibmvfc: add handlers to drain and complete Sub-CRQ responses
  ibmvfc: define Sub-CRQ interrupt handler routine
  ibmvfc: map/request irq and register Sub-CRQ interrupt handler
  ibmvfc: implement channel enquiry and setup commands
  ibmvfc: advertise client support for using hardware channels
  ibmvfc: set and track hw queue in ibmvfc_event struct
  ibmvfc: send commands down HW Sub-CRQ when channelized
  ibmvfc: register Sub-CRQ handles with VIOS during channel setup
  ibmvfc: add cancel mad initialization helper
  ibmvfc: send Cancel MAD down each hw scsi channel
  ibmvfc: purge scsi channels after transport loss/reset
  ibmvfc: enable MQ and set reasonable defaults
  ibmvfc: provide modules parameters for MQ settings

 drivers/scsi/ibmvscsi/ibmvfc.c | 917 ++++++++++++++++++++++++++++-----
 drivers/scsi/ibmvscsi/ibmvfc.h |  39 ++
 2 files changed, 828 insertions(+), 128 deletions(-)

-- 
2.27.0