[$] Supporting large block sizes

At the2023 Linux Storage, Filesystem,Memory-Management and BPF Summit, Luis Chamberlain led a plenarysession on kernel support for block sizes larger than 4KB. There areassumptions in the current kernel that the block size used by a block-layerdevice is less than or equal to the system's page size-both are usually 4KBtoday. But there have been efforts over the years to remove thatrestriction; that work may be heading toward fruition, in part because ofthe folio efforts of late, though there arestill lots of areas that need attention.