[PATCH v5 0/5] refine storing null

[Wei Yang <richard.weiyang@gmail.com>]

The original thread[1] thoughts it is a problem in mas_new_root(). But after
discussion, this should be an improvement on storing NULL.

Patch 1/2 preparation for refine.

Patch 3 remove redundant check in mas_new_root().

Patch 4 refine mas_store_root() to improve memory efficiency and remove
possible consecutive NULL slot.

Patch 5 adds a test for storing NULL.

[1]: https://lkml.kernel.org/r/20241015233909.23592-1-richard.weiyang@gmail.com

v5:
  rebase on akpm mm-unstable
  fix a build warning on xa_is_node() in patch 5

v4:
  patch 3 add a WARN_ON_ONCE()
  patch 4 add a comment and simplify the logic a little

v3:
  patch 4 move the change into mas_store_root()
  patch 5 move test into lib/test_maple_tree.c

Wei Yang (5):
  maple_tree: print empty for an empty tree on mt_dump()
  maple_tree: the return value of mas_root_expand() is not used
  maple_tree: not necessary to check index/last again
  maple_tree: refine mas_store_root() on storing NULL
  maple_tree: add a test checking storing null

 lib/maple_tree.c      | 29 ++++++++++----
 lib/test_maple_tree.c | 90 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 112 insertions(+), 7 deletions(-)

-- 
2.34.1