Re: [PATCH v2 00/20] libnd: non-volatile memory device support

[Dan Williams <dan.j.williams@intel.com>]

On Tue, Apr 28, 2015 at 5:25 PM, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
> On Tuesday, April 28, 2015 02:24:12 PM Dan Williams wrote:
>> Changes since v1 [1]: Incorporates feedback received prior to April 24.
>>
>> 1/ Ingo said [2]:
>>
>>        "So why on earth is this whole concept and the naming itself
>>        ('drivers/block/nd/' stands for 'NFIT Defined', apparently)
>>        revolving around a specific 'firmware' mindset and revolving
>>        around specific, weirdly named, overly complicated looking
>>        firmware interfaces that come with their own new weird
>>        glossary??"
>>
>>    Indeed, we of course consulted the NFIT specification to determine
>>    the shape of the sub-system, but then let its terms and data
>>    structures permeate too deep into the implementation.  That is fixed
>>    now with all NFIT specifics factored out into acpi.c.  The NFIT is no
>>    longer required reading to review libnd.  Only three concepts are
>>    needed:
>>
>>       i/ PMEM - contiguous memory range where cpu stores are
>>        persistent once they are flushed through the memory
>>          controller.
>>
>>      ii/ BLK - mmio apertures (sliding windows) that can be
>>        programmed to access an aperture's-worth of persistent
>>          media at a time.
>>
>>     iii/ DPA - "dimm-physical-address", address space local to a
>>        dimm.  A dimm may provide both PMEM-mode and BLK-mode
>>        access to a range of DPA.  libnd manages allocation of DPA
>>          to either PMEM or BLK-namespaces to resolve this aliasing.
>>
>>    The v1..v2 diffstat below shows the migration of nfit-specifics to
>>    acpi.c and the new state of libnd being nfit-free.  "nd" now only
>>    refers to "non-volatile devices".  Note, reworked documentation will
>>    return once the review has settled.
>>
>>    Documentation/blockdev/nd.txt     |  867 ---------------------
>>    MAINTAINERS                       |   34 +-
>>    arch/ia64/kernel/efi.c            |    5 +-
>>    arch/x86/kernel/e820.c            |   11 +-
>>    arch/x86/kernel/pmem.c            |    2 +-
>>    drivers/block/Makefile            |    2 +-
>>    drivers/block/nd/Kconfig          |  135 ++--
>>    drivers/block/nd/Makefile         |   32 +-
>>    drivers/block/nd/acpi.c           | 1506 +++++++++++++++++++++++++++++++------
>>    drivers/block/nd/acpi_nfit.h      |  321 ++++++++
>>    drivers/block/nd/blk.c            |   27 +-
>>    drivers/block/nd/btt.c            |    6 +-
>>    drivers/block/nd/btt_devs.c       |    8 +-
>>    drivers/block/nd/bus.c            |  337 +++++----
>>    drivers/block/nd/core.c           |  574 +-------------
>>    drivers/block/nd/dimm.c           |   11 -
>>    drivers/block/nd/dimm_devs.c      |  292 ++-----
>>    drivers/block/nd/e820.c           |  100 +++
>>    drivers/block/nd/libnd.h          |  122 +++
>>    drivers/block/nd/namespace_devs.c |   10 +-
>>    drivers/block/nd/nd-private.h     |  107 +--
>>    drivers/block/nd/nd.h             |   91 +--
>>    drivers/block/nd/nfit.h           |  238 ------
>>    drivers/block/nd/pmem.c           |   56 +-
>>    drivers/block/nd/region.c         |   78 +-
>>    drivers/block/nd/region_devs.c    |  783 +++----------------
>>    drivers/block/nd/test/iomap.c     |   86 +--
>>    drivers/block/nd/test/nfit.c      | 1115 +++++++++++++++------------
>>    drivers/block/nd/test/nfit_test.h |   15 +-
>>    include/uapi/linux/ndctl.h        |  130 ++--
>>    30 files changed, 3166 insertions(+), 3935 deletions(-)
>>    delete mode 100644 Documentation/blockdev/nd.txt
>>    create mode 100644 drivers/block/nd/acpi_nfit.h
>>    create mode 100644 drivers/block/nd/e820.c
>>    create mode 100644 drivers/block/nd/libnd.h
>>    delete mode 100644 drivers/block/nd/nfit.h
>>
>>    [1]: https://lists.01.org/pipermail/linux-nvdimm/2015-April/000484.html
>>    [2]: https://lists.01.org/pipermail/linux-nvdimm/2015-April/000520.html
>>
>> 2/ Christoph asked the pmem ida conversion to be moved to its own patch
>>    (done), and to consider leaving the current pmem.c in drivers/block/.
>>    Instead, I converted the e820-type-12 enabling to be the first
>>    non-ACPI-NFIT based consumer of libnd.  The new nd_e820 driver simply
>>    registers e820-type-12 ranges as libnd PMEM regions.  Among other
>>    things this conversion enables BTT for these ranges.  The alternative
>>    is to move drivers/block/nd/nd.h internals out to include/linux/
>>    which I think is worse.
>>
>> 3/ Toshi reported that the NFIT parsing fails to handle the case of a
>>    PMEM range with a single-dimm (non-aliasing) interleave description.
>>    Support for this case was added and is tested by default by the
>>    nfit_test.1 configuration.
>>
>> 4/ Toshi reported that we should not be treating a missing _STA property
>>    as a "dimm disabled by firmware" case.  (fixed).
>>
>> 5/ Christoph noted that ND_ARCH_HAS_IOREMAP_CACHE needs to be moved to
>>    arch code.  It is gone for now and we'll revisit when adding cached
>>    mappings back to the PMEM driver.
>>
>> 6/ Toshi mentioned that the presence of two different nd_bus_probe()
>>    functions was confusing.  (cleaned up).
>>
>> 7/ Robert asked for s/btt_checksum/nd_btt_checksum/ (done).
>>
>> 8/ Linda asked for nfit_test to honor dynamic cma reservations via the
>>    cma= command line (done).  The cma requirements have also been
>>    reduced to 128M as only the simulated DAX regions need CMA.  The rest
>>    can use vmalloc().
>>
>> ---
>>
>> Available here:
>>   git://git.kernel.org/pub/scm/linux/kernel/git/djbw/nvdimm nd-v2
>>
>> ---
>>
>> Dan Williams (18):
>>       e820, efi: add ACPI 6.0 persistent memory types
>>       libnd, nd_acpi: initial libnd infrastructure and NFIT support
>>       nd_acpi, nfit-test: manufactured NFITs for interface development
>>       libnd: ndctl class device, and nd bus attributes
>>       libnd, nd_acpi: dimm/memory-devices
>>       libnd: ndctl.h, the nd ioctl abi
>>       libnd, nd_dimm: dimm driver and base libnd device-driver infrastructure
>>       libnd, nd_acpi: regions (block-data-window, persistent memory, volatile memory)
>>       libnd: support for legacy (non-aliasing) nvdimms
>>       pmem: use ida
>>       libnd, nd_pmem: add libnd support to the pmem driver
>>       libnd, nd_acpi: add interleave-set state-tracking infrastructure
>>       libnd: namespace indices: read and validate
>>       libnd: pmem label sets and namespace instantiation.
>>       libnd: blk labels and namespace instantiation
>>       libnd: write pmem label set
>>       libnd: write blk label set
>>       libnd: infrastructure for btt devices
>>
>> Ross Zwisler (1):
>>       libnd, nd_acpi, nd_blk: driver for BLK-mode access persistent memory
>>
>> Vishal Verma (1):
>>       nd_btt: atomic sector updates
>
> I'm wondering what's wrong with CCing all of the series to linux-acpi?
>
> Is there anything in it that the people on that list should not see, by any
> chance?

linux-acpi may not care about the dimm-metadata labeling patches that
are completely independent of ACPI, but might as well include
linux-acpi on the whole series at this point.