[PATCH v4 0/4] pstore: add multi-backend suuport

[Yuanhe Shu <xiangzao@linux.alibaba.com>]

This is the 4th version of the patch set. In this patchset we aim to add
pstore multi-backend support then user can register more than one pstore
backend.

Changes in v4:
- Replace all rcu_read_lock with mutex
- Move bif_oops_buf, max_compressed_size and pstore_dumper into
  pstore_info_list
- add a helper to do "is this name in the list" and a helper to do
  "is this backend loaded"
- make comments in pstore_(un)register clearer
- return the max_seen ret or the first negative err in write_pmsg()
- add a /sys/module entry for the list of backends, comma separated
- Link to v3: https://lore.kernel.org/all/20230928024244.257687-1-xiangzao@linux.alibaba.com/

Changes in v3:
- Fix ftrace.c build error
- Link to v2: https://lore.kernel.org/all/20240205122852.7069-1-xiangzao@linux.alibaba.com/

Changes in v2:
- pstore.backend no longer acts as "registered backend", but
  "backends eligible for registration".
- drop subdir since it will break user space
- drop tty frontend since I haven't yet devised a satisfactory
  implementation strategy
- Link to v1: https://lore.kernel.org/all/20230928024244.257687-1-xiangzao@linux.alibaba.com/

Yuanhe Shu (4):
  pstore: add multi-backend support
  pstore: add a /sys/module entry for loaded backends
  Documentation: adjust pstore backend related document
  tools/testing: adjust pstore backend related selftest

 Documentation/ABI/testing/pstore              |   8 +-
 .../admin-guide/kernel-parameters.txt         |   4 +-
 fs/pstore/ftrace.c                            |  27 +-
 fs/pstore/inode.c                             |  57 +++-
 fs/pstore/internal.h                          |   5 +-
 fs/pstore/platform.c                          | 274 ++++++++++++------
 fs/pstore/pmsg.c                              |  27 +-
 include/linux/pstore.h                        |  23 ++
 tools/testing/selftests/pstore/common_tests   |   8 +-
 .../selftests/pstore/pstore_post_reboot_tests |  67 +++--
 tools/testing/selftests/pstore/pstore_tests   |   2 +-
 11 files changed, 358 insertions(+), 144 deletions(-)

-- 
2.39.3