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

Rafael J. Wysocki
2015-04-29T00:00:12Z

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?

Like patch [01/20], for the most obvious example. It even has "ACPI 6" in the
subject ...

Rafael