libnvdimm, pfn: fix 'npfns' vs section alignment
authorDan Williams <dan.j.williams@intel.com>
Fri, 5 May 2017 02:54:42 +0000 (19:54 -0700)
committerDan Williams <dan.j.williams@intel.com>
Fri, 5 May 2017 02:54:42 +0000 (19:54 -0700)
commitd5483feda85a8f39ee2e940e279547c686aac30c
treeb1ab04326fddfa2f8c4c8442c60a3ae664d92cd7
parent9d62ed96511823fa9c2ac7a819d7b4be22a9a6de
libnvdimm, pfn: fix 'npfns' vs section alignment

Fix failures to create namespaces due to the vmem_altmap not advertising
enough free space to store the memmap.

 WARNING: CPU: 15 PID: 8022 at arch/x86/mm/init_64.c:656 arch_add_memory+0xde/0xf0
 [..]
 Call Trace:
  dump_stack+0x63/0x83
  __warn+0xcb/0xf0
  warn_slowpath_null+0x1d/0x20
  arch_add_memory+0xde/0xf0
  devm_memremap_pages+0x244/0x440
  pmem_attach_disk+0x37e/0x490 [nd_pmem]
  nd_pmem_probe+0x7e/0xa0 [nd_pmem]
  nvdimm_bus_probe+0x71/0x120 [libnvdimm]
  driver_probe_device+0x2bb/0x460
  bind_store+0x114/0x160
  drv_attr_store+0x25/0x30

In commit 658922e57b84 "libnvdimm, pfn: fix memmap reservation sizing"
we arranged for the capacity to be allocated, but failed to also update
the 'npfns' parameter. This leads to cases where there is enough
capacity reserved to hold all the allocated sections, but
vmemmap_populate_hugepages() still encounters -ENOMEM from
altmap_alloc_block_buf().

This fix is a stop-gap until we can teach the core memory hotplug
implementation to permit sub-section hotplug.

Cc: <stable@vger.kernel.org>
Fixes: 658922e57b84 ("libnvdimm, pfn: fix memmap reservation sizing")
Reported-by: Anisha Allada <anisha.allada@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
drivers/nvdimm/pfn_devs.c