This series adds Kunit tests for fs/ext4/hash.c and refactors
the str2hashbuf_{signed,unsigned}() helpers.

Patch 1 adds test coverage for ext4fs_dirhash(), including the main
hash variants and relevant edge cases.

Patch 2 simplifies the str2hashbuf helper implementation by processing
input in 4-byte chunks and removing function-pointer dispatch. This also
reduces overhead and shows roughly 2x improvement on longer inputs in
local testing.

Thanks,
Guan-Chun Wu

Link: https://lore.kernel.org/all/20260413065114.730231-1-409411716@gms.tku.edu.tw/

---

v3 -> v4 :

  - Fix a modpost undefined symbol error for ext4fs_dirhash when building
    ext4-test.ko.

---

Guan-Chun Wu (2):
  ext4: add Kunit coverage for directory hash computation
  ext4: improve str2hashbuf by processing 4-byte chunks and removing
    function pointers

 fs/ext4/Makefile    |   2 +-
 fs/ext4/hash-test.c | 546 ++++++++++++++++++++++++++++++++++++++++++++
 fs/ext4/hash.c      |  67 ++++--
 3 files changed, 592 insertions(+), 23 deletions(-)
 create mode 100644 fs/ext4/hash-test.c

-- 
2.34.1