[PATCH v2 00/33] ibmvfc: NVMe/FC support over IBM Virtual FC

[Tyrel Datwyler <tyreld@linux.ibm.com>]

This series adds NVMe/FC initiator support to the ibmvfc driver, enabling
IBM POWER virtual machines to discover and use NVMe namespaces presented by
the IBM Virtual I/O Server (VIOS) over the existing NPIV transport.

The ibmvfc driver communicates with the VIOS via a CRQ-based protocol. With
this series the VIOS can present both SCSI/FCP and NVMe/FC targets through
parallel sets of protocol-specific MAD opcodes, fabric login flows, and
sub-CRQ channels.

The series is organized into three phases:

Patches 1-5: Bug fixes and preparatory refactoring
  Four pre-existing bugs are fixed before any NVMe/FC work is introduced:
  a deadlock in the MAD send-failure path (locked done variant called with
  host_lock already held), a race during driver teardown where
  rport_add_work_q work items can outlive the FC host, a NULL event
  dereference in ibmvfc_tgt_implicit_logout_and_del, and an allocator
  mismatch where mempool-allocated ibmvfc_target structs are freed via kfree
  rather than mempool_free. Patch 5 moves the target list and count from
  struct ibmvfc_host into struct ibmvfc_channels as the structural
  prerequisite for independent per-protocol target tracking.

Patches 6-27: Protocol interface and driver scaffolding
  Patch 6 extends ibmvfc.h with NVMe/FC protocol definitions: MAD opcodes,
  capability flags, the v3 command layout, the fabric login MAD, async
  sub-CRQ event format, and updated channel enquiry/setup fields. Patch 7
  splits ibmvfc.c into ibmvfc-core.c and the new ibmvfc-nvme.c/h, registers
  an nvme_fc_port_template with stub callbacks, and adds NVMe module
  parameters. The remaining patches build the NVMe/FC plumbing: NVMe
  channel-group initialization, sub-CRQ lifecycle management, protocol-
  specific fabric login flow, target discovery, PLOGI/PRLI/query-target,
  implicit logout, move-login, protocol-driven target allocation, NVMe
  target deletion, state machine updates, and local/remote port registration
  with the NVMe-FC transport layer.

Patches 28-33: NVMe-FC LLDD callbacks and I/O path
  Implements the full nvme_fc_port_template: create_queue/delete_queue map
  NVMe controller queues to sub-CRQ handles; ls_req submits FC-LS frames via
  the ibmvfc passthru MAD; fcp_io builds and submits NVMe FCP commands via
  the NVMe sub-CRQ and completes them via nvme_fc_rcv_fcp_rsp(); ls_abort
  and fcp_abort cancel outstanding requests via NVMF cancel MADs. Patch 33
  extends the purge path to fail outstanding NVMe FCP and LS requests during
  host reset and link-down events.

Changes since v1 (29 patches -> 33 patches)
--------------------------------------------
  - Added four bug-fix patches (1-4) ahead of any NVMe/FC changes to ensure
    the series is bisect-safe. These address issues identified in the v1
    review: the mempool_free/kfree mismatch (previously flagged on multiple
    patches), the rport_add_work_q teardown race, the NULL event dereference
    in the implicit logout and delete path, and the MAD send-failure deadlock
    due to the locked done handler being invoked with host_lock already held.
  - Fixed the NULL pointer dereference in ibmvfc_nvme_unregister() and
    ibmvfc_nvme_unregister_remoteport() by adding proper NULL guards before
    dereferencing the local and remote port pointers (v1 patch 19/20).
  - Fixed self-deadlock in ibmvfc_send_event() error path for MAD commands:
    on send failure the driver now falls back to the unlocked evt->_done
    handler instead of the locked variant (patch 1 in v2).
  - Fixed NVMe targets being entirely ignored by the TGT_DEL and TGT_DEL_FAILED
    work-loop actions; both the SCSI and NVMe target lists are now walked in
    the relevant state machine helpers (v1 patches 18/21).
  - Fixed the purge path omission: NVMe FCP and LS requests are now properly
    failed during host reset (patch 33, expanded from v1 patch 29 which only
    handled the transport reset case).

Tyrel Datwyler (33):
  ibmvfc: don't call locked done variant for MADs on send failure
  ibmvfc: flush rport_add_work_q during driver teardown
  ibmvfc: check for NULL evt in implicit LOGO and target delete path
  ibmvfc: free ibmvfc_target allocations with mempool_free
  ibmvfc: move target list from host to protocol specific channel groups
  ibmvfc: add NVMe/FC protocol interface definitions
  ibmvfc: split NVMe support into separate source file and add transport stubs
  ibmvfc: initialize NVMe channel configuration during probe
  ibmvfc: alloc/dealloc sub-queues for nvme channels
  ibmvfc: add logic for protocol specific fabric login
  ibmvfc: add wrapper to get vhost associated with a channel group
  ibmvfc: add helper for creating protocol specific discover target events
  ibmvfc: add helper to check NVMe/FC support with active queues
  ibmvfc: allocate and free NVMe channel group discovery buffers
  ibmvfc: send NVMe target discovery MAD
  ibmvfc: add NVMe/FC Implicit Logout and Move Login support
  ibmvfc: add NVMe/FC Port Login support
  ibmvfc: add NVMe/FC Process Login support
  ibmvfc: add NVMe/FC Query Target support
  ibmvfc: allocate targets based on protocol
  ibmvfc: delete NVMe/FC targets as well as SCSI
  ibmvfc: update state machine to process NVMe/FC targets
  ibmvfc: implement NVMe/FC stubs for local/remote port registration
  ibmvfc: register local nvme fc port after fabric login
  ibmvfc: process NVMe/FC rports in work thread
  ibmvfc: extend ibmvfc_debug visibility to ibmvfc-nvme.c
  ibmvfc: declare global function definitions
  ibmvfc: implement LLDD callbacks for mapping nvme-fc queues
  ibmvfc: implement nvme-fc LS submission transport callback
  ibmvfc: implement nvme-fc IO command submission callback
  ibmvfc: implement nvme-fc LS abort handling callback
  ibmvfc: implement nvme-fc FCP abort callback
  ibmvfc: fail nvme-fc fcp-io and ls requests during host reset

 drivers/scsi/ibmvscsi/Makefile                     |   2 +
 drivers/scsi/ibmvscsi/{ibmvfc.c => ibmvfc-core.c}  | ...
 drivers/scsi/ibmvscsi/ibmvfc-nvme.c                | ...
 drivers/scsi/ibmvscsi/ibmvfc-nvme.h                | ...
 drivers/scsi/ibmvscsi/ibmvfc.h                     | ...
 5 files changed

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2.55.0