This series decouples the compatibility tracking and code organization
of individual KHO subsystems (radix tree, vmalloc, and block device).
The diff here is a bit larger than I'd like, but most of it is just
refactoring and moving code around to modularize the subsystems rather
than functional changes.
Specifically, this series separates KHO data structures from KHO
core functionality:
- KHO data structures are those that have ABI checks between kernel
versions (e.g., vmalloc, radix trees, and block devices).
- KHO core is the functionality that involves passing the memory
from one kernel to another.
KHO core depends on some of these data structures, but other users
of KHO also depend on them. The number of data structures keeps
growing: first we introduced vmalloc, then radix trees, then
linked blocks, and next we are planning to add an xarray-like
data structure. Keeping all of this within the same `kexec_handover.c`
file, and also under the same global version, is no longer sustainable.
To address this, this series:
1. Refactors and reorganizes the code by splitting out radix tree
and vmalloc into separate files.
2. Moves and organizes internal and ABI headers into structured
directories under include/linux/kho/ and include/linux/kho/abi/.
Instead of cluttering include/linux/ with prefix-styled headers like
kho_block.h or kho_radix_tree.h, we use the already existing
include/linux/kho/ directory (e.g., kho/block.h and
kho/radix_tree.h).
3. Introduces a standard set of compatibility helpers in
kho/abi/compat.h.
4. Decouples the compatibility strings of individual KHO subsystems
(radix tree, vmalloc, and block) from the global KHO version.
This enables independent, granular compatibility versioning.
5. Adds a KUnit test suite to verify that the composite compatibility
strings of different subsystems remain unique and sorted in
alphabetical order, guaranteeing a consistent and predictable
representation across configurations.
This series is to gather feedback on the overall design and layout
of the granular compatibility mechanism.
Pasha Tatashin (9):
kho: split out radix tree tracker into kho_radix.c
kho: split radix tree headers out of kexec_handover.h
kho: split out vmalloc preservation into kho_vmalloc.c
kho: split vmalloc headers out of kexec_handover.h
kho: move kho_block.h to kho/block.h
kho: introduce compatibility helpers and decouple block version
kho: decouple radix tree compatibility from global KHO version
kho: decouple vmalloc compatibility from global KHO version and update
memfd
liveupdate: add KUnit test to verify alphabetical order of
compatibility strings
Documentation/core-api/kho/abi.rst | 11 +-
Documentation/core-api/kho/index.rst | 10 +-
MAINTAINERS | 1 -
include/linux/kexec_handover.h | 18 -
include/linux/kho/abi/block.h | 4 +-
include/linux/kho/abi/compat.h | 33 ++
include/linux/kho/abi/kexec_handover.h | 203 +------
include/linux/kho/abi/luo.h | 8 +-
include/linux/kho/abi/memfd.h | 12 +-
include/linux/kho/abi/radix_tree.h | 133 +++++
include/linux/kho/abi/vmalloc.h | 101 ++++
include/linux/{kho_block.h => kho/block.h} | 2 +-
.../{kho_radix_tree.h => kho/radix_tree.h} | 5 +-
include/linux/kho/vmalloc.h | 34 ++
kernel/liveupdate/Kconfig | 15 +
kernel/liveupdate/Makefile | 9 +-
kernel/liveupdate/kexec_handover.c | 531 +-----------------
kernel/liveupdate/kho_block.c | 2 +-
kernel/liveupdate/kho_radix.c | 290 ++++++++++
kernel/liveupdate/kho_vmalloc.c | 274 +++++++++
kernel/liveupdate/liveupdate_test.c | 56 ++
kernel/liveupdate/luo_internal.h | 2 +-
kernel/liveupdate/luo_session.c | 2 +-
lib/test_kho.c | 1 +
mm/memfd_luo.c | 1 +
tools/testing/selftests/liveupdate/config | 1 +
26 files changed, 997 insertions(+), 762 deletions(-)
create mode 100644 include/linux/kho/abi/compat.h
create mode 100644 include/linux/kho/abi/radix_tree.h
create mode 100644 include/linux/kho/abi/vmalloc.h
rename include/linux/{kho_block.h => kho/block.h} (100%)
rename include/linux/{kho_radix_tree.h => kho/radix_tree.h} (96%)
create mode 100644 include/linux/kho/vmalloc.h
create mode 100644 kernel/liveupdate/kho_radix.c
create mode 100644 kernel/liveupdate/kho_vmalloc.c
create mode 100644 kernel/liveupdate/liveupdate_test.c
base-commit: 5fb813ae0009d97fc414f08ad73286f562e9a123
--
2.53.0
