The following namespace configuration attempt:

# ndctl create-namespace -e namespace0.0 -m devdax -a 1G -f libndctl: ndctl_dax_enable: dax0.1: failed to enable Error: namespace0.0: failed to enable

failed to reconfigure namespace: No such device or address

...fails when the backing memory range is not physically aligned to 1G:

# cat /proc/iomem | grep Persistent 210000000-30fffffff : Persistent Memory (legacy)

In the above example the 4G persistent memory range starts and ends on a 256MB boundary.

We handle this case correctly when needing to handle cases that violate section alignment (128MB) collisions against "System RAM", and we simply need to extend that padding/truncation for the 1GB alignment use case.

Cc: stable@vger.kernel.org Fixes: 315c562536c4 ("libnvdimm, pfn: add 'align' attribute...") Reported-and-tested-by: Jane Chu jane.chu@oracle.com Signed-off-by: Dan Williams dan.j.williams@intel.com --- drivers/nvdimm/pfn_devs.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c index 65cc171c721d..5ba9ab7af736 100644 --- a/drivers/nvdimm/pfn_devs.c +++ b/drivers/nvdimm/pfn_devs.c @@ -582,6 +582,12 @@ static struct vmem_altmap *__nvdimm_setup_pfn(struct nd_pfn *nd_pfn, return altmap; }

+static u64 phys_pmem_align_down(struct nd_pfn *nd_pfn, u64 phys) +{ + return min_t(u64, PHYS_SECTION_ALIGN_DOWN(phys), + ALIGN_DOWN(phys, nd_pfn->align)); +} + static int nd_pfn_init(struct nd_pfn *nd_pfn) { u32 dax_label_reserve = is_nd_dax(&nd_pfn->dev) ? SZ_128K : 0; @@ -637,13 +643,16 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn) start = nsio->res.start; size = PHYS_SECTION_ALIGN_UP(start + size) - start; if (region_intersects(start, size, IORESOURCE_SYSTEM_RAM, - IORES_DESC_NONE) == REGION_MIXED) { + IORES_DESC_NONE) == REGION_MIXED + || !IS_ALIGNED(start + resource_size(&nsio->res), + nd_pfn->align)) { size = resource_size(&nsio->res); - end_trunc = start + size - PHYS_SECTION_ALIGN_DOWN(start + size); + end_trunc = start + size - phys_pmem_align_down(nd_pfn, + start + size); }

if (start_pad + end_trunc) - dev_info(&nd_pfn->dev, "%s section collision, truncate %d bytes\n", + dev_info(&nd_pfn->dev, "%s alignment collision, truncate %d bytes\n", dev_name(&ndns->dev), start_pad + end_trunc);

/*