Commit 658922e5 authored Apr 30, 2016 by Dan Williams

libnvdimm, pfn: fix memmap reservation sizing



When configuring a pfn-device instance to allocate the memmap array it
needs to account for the fact that vmemmap_populate_hugepages()
allocates struct page blocks in HPAGE_SIZE chunks.  We need to align the
reserved area size to 2MB otherwise arch_add_memory() runs out of memory
while establishing the memmap:

 WARNING: CPU: 0 PID: 496 at arch/x86/mm/init_64.c:704 arch_add_memory+0xe7/0xf0
 [..]
 Call Trace:
  [<ffffffff8148bdb3>] dump_stack+0x85/0xc2
  [<ffffffff810a749b>] __warn+0xcb/0xf0
  [<ffffffff810a75cd>] warn_slowpath_null+0x1d/0x20
  [<ffffffff8106a497>] arch_add_memory+0xe7/0xf0
  [<ffffffff811d2097>] devm_memremap_pages+0x287/0x450
  [<ffffffff811d1ffa>] ? devm_memremap_pages+0x1ea/0x450
  [<ffffffffa0000298>] __wrap_devm_memremap_pages+0x58/0x70 [nfit_test_iomap]
  [<ffffffffa0047a58>] pmem_attach_disk+0x318/0x420 [nd_pmem]
  [<ffffffffa0047bcf>] nd_pmem_probe+0x6f/0x90 [nd_pmem]
  [<ffffffffa0009469>] nvdimm_bus_probe+0x69/0x110 [libnvdimm]
 [..]
  ndbus0: nd_pmem.probe(pfn3.0) = -12
 nd_pmem: probe of pfn3.0 failed with error -12
libndctl: ndctl_pfn_enable: pfn3.0: failed to enable

Reported-by: Namratha Kothapalli <namratha.n.kothapalli@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

parent 02da2d72

drivers/nvdimm/pmem.c

+10 −3

Original line number	Diff line number	Diff line
		@@ -397,10 +397,17 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn)
		*/
		start += start_pad;
		npfns = (pmem->size - start_pad - end_trunc - SZ_8K) / SZ_4K;
		if (nd_pfn->mode == PFN_MODE_PMEM)
		offset = ALIGN(start + SZ_8K + 64 * npfns, nd_pfn->align)
		if (nd_pfn->mode == PFN_MODE_PMEM) {
		unsigned long memmap_size;

		/*
		* vmemmap_populate_hugepages() allocates the memmap array in
		* HPAGE_SIZE chunks.
		*/
		memmap_size = ALIGN(64 * npfns, HPAGE_SIZE);
		offset = ALIGN(start + SZ_8K + memmap_size, nd_pfn->align)
		- start;
		else if (nd_pfn->mode == PFN_MODE_RAM)
		} else if (nd_pfn->mode == PFN_MODE_RAM)
		offset = ALIGN(start + SZ_8K, nd_pfn->align) - start;
		else
		goto err;

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