On Sat, Aug 12, 2017 at 07:44:14PM -0700, Dan Williams wrote: > How about MAP_SYNC == (MAP_SHARED|MAP_PRIVATE)? On older kernels that > should get -EINVAL, and on new kernels it means SYNC+SHARED. Cute trick, but I'd hate to waster it just for our little flag. How about: #define __MAP_VALIDATE MAP_SHARED|MAP_PRIVATE #define MAP_SYNC 0x??? | __MAP_VALIDATE so that we can reuse that trick for any new flag?
