Re: [PATCH v2 00/13] mpt3sas driver NVMe support:

[Hannes Reinecke]

On 07/14/2017 03:22 PM, Suganath Prabu S wrote:
> Ventura Series controller are Tri-mode. The controller and
> firmware are capable of supporting NVMe devices and
> PCIe switches to be connected with the controller. This
> patch set adds driver level support for NVMe devices and
> PCIe switches.
> 
> Suganath Prabu S (13):
>   mpt3sas: Update MPI Header
>   mpt3sas: Add nvme device support in slave alloc, target alloc and
>     probe
>   mpt3sas: SGL to PRP Translation for I/Os to NVMe  devices
>   mpt3sas: Added support for nvme encapsulated request message.
>   mpt3sas: API 's to support NVMe drive addition to SML
>   mpt3sas: API's to remove nvme drive from sml
>   mpt3sas: Handle NVMe PCIe device related events generated            
>        from firmware.
>   mpt3sas: Set NVMe device queue depth as 128
>   mpt3sas: scan and add nvme device after controller reset
>   mpt3as: Add-Task-management-debug-info-for-NVMe-drives.
>   mpt3sas: NVMe drive support for BTDHMAPPING ioctl command and log
>     info
>   mpt3sas: Fix nvme drives checking for tlr.
>   mpt3sas: Update mpt3sas driver version.
> 
>  drivers/scsi/mpt3sas/mpi/mpi2.h          |   43 +-
>  drivers/scsi/mpt3sas/mpi/mpi2_cnfg.h     |  647 ++++++++++-
>  drivers/scsi/mpt3sas/mpi/mpi2_init.h     |   11 +-
>  drivers/scsi/mpt3sas/mpi/mpi2_ioc.h      |  331 ++++++-
>  drivers/scsi/mpt3sas/mpi/mpi2_pci.h      |  142 +++
>  drivers/scsi/mpt3sas/mpi/mpi2_tool.h     |   14 +-
>  drivers/scsi/mpt3sas/mpt3sas_base.c      |  710 +++++++++++-
>  drivers/scsi/mpt3sas/mpt3sas_base.h      |  171 +++-
>  drivers/scsi/mpt3sas/mpt3sas_config.c    |  100 ++
>  drivers/scsi/mpt3sas/mpt3sas_ctl.c       |  158 ++-
>  drivers/scsi/mpt3sas/mpt3sas_scsih.c     | 1874 ++++++++++++++++++++++++++++--
>  drivers/scsi/mpt3sas/mpt3sas_warpdrive.c |    2 +-
>  12 files changed, 4063 insertions(+), 140 deletions(-)
>  create mode 100644 drivers/scsi/mpt3sas/mpi/mpi2_pci.h
> 
I'm not happy with this approach.
NVMe devices should _not_ appear as SCSI devices; this will just confuse
matters _and_ will be incompatible with 'normal' NVMe devices.

Rather I would like to see the driver to hook into the existing NVMe
framework (which essentially means to treat the mpt3sas as a weird
NVMe-over-Fabrics HBA), and expose the NVMe devices like any other NVMe HBA.

I'm sorry that you'll have to redo your patchset (again), but this is
the only way I see how this patchset can be brought forward.

I'd be happy to discuss implementation details with you.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		   Teamlead Storage & Networking
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