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Commit 41fce90f authored by Dan Williams's avatar Dan Williams
Browse files

libnvdimm, dax: fix 1GB-aligned namespaces vs physical misalignment 



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: 315c5625 ("libnvdimm, pfn: add 'align' attribute...")
Reported-and-tested-by: default avatarJane Chu <jane.chu@oracle.com>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 19deaa21

drivers/nvdimm/pfn_devs.c

+12 −3
Original line number Diff line number Diff line
@@ -583,6 +583,12 @@ 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;
@@ -638,13 +644,16 @@ 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);



	/*