mm/damon/core: hide core-private struct fields

DAMON core structs hide core-private fields using 'private:' comment tags. It is incomplete and inconsistent. The linked list heads in a few structs, for example, are intended to be hidden, and always be used using the wrapper macros like damon_for_each_region(). But those were mistakenly marked as non-private. A few core layer-only fields were also mistakenly added as non-private.

This only encourages callers to directly use the private fields. It is easy to make mistakes, and difficult to control. Mark all such DAMON core struct fields as private.

Patches 1-8 mark the private fields for damon_region, damon_target, damos_quota_goal, damos_quota, damos_filter, damos, damon_filter and damon_probe, respectively. Patch 9 removes DAMON_SYSFS's direct access to core-private field, damon_ctx->ops. Finally patch 10 mark the private fields for damon_ctx.

Changes from RFC v1
- RFC v1: https://lore.kernel.org/[email protected]
- Drop RFC tag.

SJ Park (10):
mm/damon/core: hide private damon_region fields mm/damon/core: hide private damon_target fields mm/damon/core: hide private damos_quota_goal fields mm/damon/core: hide private damos_quota fields mm/damon/core: hide private damos_filter fields mm/damon/core: hide private damos fields mm/damon/core: hide private damon_filter fields mm/damon/core: hide private damon_probe fields mm/damon/sysfs: do not directly access damon_ctx->ops mm/damon/core: hide core-private damon_ctx fields

 include/linux/damon.h | 110 +++++++++++++++++++++++-------------------
 mm/damon/sysfs.c      |   2 +-
 2 files changed, 62 insertions(+), 50 deletions(-)

base-commit: 4c0f8c26ecc149f268b6c488e6cbde2a4e58160a

2.47.3