Hello stable team, These patches have been shipping in mainline since v5.7-rc1 with no reported issues. They address long standing problems in libnvdimm's handling of namespace provisioning relative to alignment constraints including crashes trying to even load the driver on some PowerPC configurations. I did fold one build fix [1] into "libnvdimm/region: Introduce an 'align' attribute" so as to not convey the bisection breakage to -stable. Please consider them for v5.4-stable. They do pass the latest version of the ndctl unit tests. [1]: 04ff4863e126 libnvdimm/region: Fix build error --- Original cover letter for the series: Aneesh reports that PowerPC requires 16MiB alignment for the address range passed to devm_memremap_pages(), and Jeff reports that it is possible to create a misaligned namespace which blocks future namespace creation in that region. Both of these issues require namespace alignment to be managed at the region level rather than padding at the namespace level which has been a broken approach to date. Introduce memremap_compat_align() to indicate the hard requirements of an arch's memremap_pages() implementation. Use the maximum known memremap_compat_align() to set the default namespace alignment for libnvdimm. Consult that alignment when allocating free space. Finally, allow the default region alignment to be overridden to maintain the same namespace creation capability as previous kernels (modulo dax operation not being supported with a non-zero start_pad). --- Aneesh Kumar K.V (1): libnvdimm/pfn_dev: Don't clear device memmap area during generic namespace probe Dan Williams (6): mm/memremap_pages: Kill unused __devm_memremap_pages() mm/memremap_pages: Introduce memremap_compat_align() libnvdimm/pfn: Prevent raw mode fallback if pfn-infoblock valid libnvdimm/namespace: Enforce memremap_compat_align() libnvdimm/region: Introduce NDD_LABELING libnvdimm/region: Introduce an 'align' attribute arch/powerpc/Kconfig | 1 arch/powerpc/mm/ioremap.c | 21 +++++ arch/powerpc/platforms/pseries/papr_scm.c | 2 drivers/acpi/nfit/core.c | 4 + drivers/nvdimm/dimm.c | 2 drivers/nvdimm/dimm_devs.c | 95 +++++++++++++++++---- drivers/nvdimm/namespace_devs.c | 28 ++++++ drivers/nvdimm/nd.h | 3 - drivers/nvdimm/pfn.h | 12 +++ drivers/nvdimm/pfn_devs.c | 48 +++++++++-- drivers/nvdimm/region_devs.c | 130 ++++++++++++++++++++++++++--- include/linux/io.h | 2 include/linux/libnvdimm.h | 2 include/linux/memremap.h | 8 ++ include/linux/mmzone.h | 1 lib/Kconfig | 3 + mm/memremap.c | 23 +++++ 17 files changed, 335 insertions(+), 50 deletions(-) base-commit: 1cdaf895c99d319c0007d0b62818cf85fc4b087f