libnvdimm for 4.14 * Media error handling support in the Block Translation Table (BTT) driver is reworked to address sleeping-while-atomic locking and memory-allocation-context conflicts. * The dax_device lookup overhead for xfs and ext4 is moved out of the iomap hot-path to a mount-time lookup. * A new 'ecc_unit_size' sysfs attribute is added to advertise the read-modify-write boundary property of a persistent memory range. * Preparatory fix-ups for arm and powerpc pmem support are included along with other miscellaneous fixes.