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Subject: [PATCH 0/7] libnvdimm/pfn: Fix section-alignment padding
From:   Dan Williams <dan.j.williams@intel.com>
To:     linux-nvdimm@lists.01.org
Cc:     "Darrick J. Wong" <darrick.wong@oracle.com>,
        stable@vger.kernel.org, Jan Kara <jack@suse.cz>,
        Oliver O'Halloran <oohall@gmail.com>,
        Jeff Moyer <jmoyer@redhat.com>,
        Johannes Thumshirn <jthumshirn@suse.de>,
        linux-kernel@vger.kernel.org, vishal.l.verma@intel.com,
        linux-fsdevel@vger.kernel.org
Date:   Tue, 12 Feb 2019 13:24:40 -0800
Message-ID: <155000668075.348031.9371497273408112600.stgit@dwillia2-desk3.amr.corp.intel.com>
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Lately Linux has encountered platforms that collide Persistent Memory
regions between each other, specifically cases where ->start_pad needed
to be non-zero. This lead to commit ae86cbfef381 "libnvdimm, pfn: Pad
pfn namespaces relative to other regions". That commit allowed
namespaces to be mapped with devm_memremap_pages(). However dax
operations on those configurations currently fail if attempted within the
->start_pad range because pmem_device->data_offset was still relative to
raw resource base not relative to the section aligned resource range
mapped by devm_memremap_pages().

Luckily __bdev_dax_supported() caught these failures and simply disabled
dax. However, to fix this situation a non-backwards compatible change
needs to be made to the interpretation of the nd_pfn info-block.
->start_pad needs to be accounted in ->map.map_offset (formerly
->data_offset), and ->map.map_base (formerly ->phys_addr) needs to be
adjusted to the section aligned resource base used to establish
->map.map formerly (formerly ->virt_addr).

See patch 7 "libnvdimm/pfn: Fix 'start_pad' implementation" for more
details, and the ndctl patch series "Improve support + testing for
labels + info-blocks" for the corresponding regression test.

---

Dan Williams (7):
      libnvdimm/pfn: Account for PAGE_SIZE > info-block-size in nd_pfn_init()
      libnvdimm/pmem: Honor force_raw for legacy pmem regions
      dax: Check the end of the block-device capacity with dax_direct_access()
      libnvdimm/pfn: Introduce super-block minimum version requirements
      libnvdimm/pfn: Remove dax_label_reserve
      libnvdimm/pfn: Introduce 'struct pfn_map_info'
      libnvdimm/pfn: Fix 'start_pad' implementation


 drivers/dax/pmem.c              |    9 +-
 drivers/dax/super.c             |   39 ++++++--
 drivers/nvdimm/namespace_devs.c |    4 +
 drivers/nvdimm/nd.h             |   15 +++
 drivers/nvdimm/pfn.h            |    4 +
 drivers/nvdimm/pfn_devs.c       |  181 ++++++++++++++++++++++++++++-----------
 drivers/nvdimm/pmem.c           |  111 +++++++++++-------------
 drivers/nvdimm/pmem.h           |   12 ---
 tools/testing/nvdimm/pmem-dax.c |   15 ++-
 9 files changed, 244 insertions(+), 146 deletions(-)