• Dan Williams's avatar
    libnvdimm: fix blk free space accounting · fe514739
    Dan Williams authored
    Commit a1f3e4d6 "libnvdimm, region: update nd_region_available_dpa()
    for multi-pmem support" reworked blk dpa (DIMM Physical Address)
    accounting to comprehend multiple pmem namespace allocations aliasing
    with a given blk-dpa range.
    
    The following call trace is a result of failing to account for allocated
    blk capacity.
    
     WARNING: CPU: 1 PID: 2433 at tools/testing/nvdimm/../../../drivers/nvdimm/names
    4 size_store+0x6f3/0x930 [libnvdimm]
     nd_region region5: allocation underrun: 0x0 of 0x1000000 bytes
     [..]
     Call Trace:
      dump_stack+0x86/0xc3
      __warn+0xcb/0xf0
      warn_slowpath_fmt+0x5f/0x80
      size_store+0x6f3/0x930 [libnvdimm]
      dev_attr_store+0x18/0x30
    
    If a given blk-dpa allocation does not alias with any pmem ranges then
    the full allocation should be accounted as busy space, not the size of
    the current pmem contribution to the region.
    
    The thinkos that led to this confusion was not realizing that the struct
    resource management is already guaranteeing no collisions between pmem
    allocations and blk allocations on the same dimm. Also, we do not try to
    support blk allocations in aliased pmem holes.
    
    This patch also fixes a case where the available blk goes negative.
    
    Cc: <stable@vger.kernel.org>
    Fixes: a1f3e4d6 ("libnvdimm, region: update nd_region_available_dpa() for multi-pmem support").
    Reported-by: default avatarDariusz Dokupil <dariusz.dokupil@intel.com>
    Reported-by: default avatarDave Jiang <dave.jiang@intel.com>
    Reported-by: default avatarVishal Verma <vishal.l.verma@intel.com>
    Tested-by: default avatarDave Jiang <dave.jiang@intel.com>
    Tested-by: default avatarVishal Verma <vishal.l.verma@intel.com>
    Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
    fe514739
dimm_devs.c 15.7 KB