Description: mm: get rid of vmacache_flush_all() entirely
References:
 https://googleprojectzero.blogspot.com/2018/09/a-cache-invalidation-bug-in-linux.html
 https://bugs.chromium.org/p/project-zero/issues/detail?id=1664
Notes:
 carnil> Introduced in 3.16-rc1 with 6b4ebc3a9078c5b7b8c4cf495a0b1d2d0e0bfe7a
Bugs:
upstream: released (4.19-rc4) [7a9cdebdcc17e426fb5287e4a82db1dfe86339b2]
4.9-upstream-stable: released (4.9.128) [84580567f1f856d2c7a610273315852e345bc3ac]
3.16-upstream-stable: released (3.16.58) [mm-get-rid-of-vmacache_flush_all-entirely.patch]
sid: released (4.18.10-1)
4.9-stretch-security: released (4.9.110-3+deb9u5) [bugfix/all/mm-get-rid-of-vmacache_flush_all-entirely.patch]
3.16-jessie-security: released (3.16.59-1)