Introduce Sequence Number Ops

Sequence Number api provides interfaces for unsigned atomic up counters.

There are a number of atomic_t usages in the kernel where atomic_t api is used for counting sequence numbers and other statistical counters. Several of these usages, convert atomic_read() and atomic_inc_return() return values to unsigned. Introducing sequence number ops supports these use-cases with a standard core-api.

Sequence Number ops provide interfaces to initialize, increment and get the sequence number. These ops also check for overflow and log message to indicate when overflow occurs. This check is intended to help catch cases where overflow could lead to problems.

Since v2:
- Uses atomic_inc_return() for incrementing the sequence number.
- No longer uses atomic_read()

Shuah Khan (7):
seqnum_ops: Introduce Sequence Number Ops
selftests: lib:test_seqnum_ops: add new test for seqnum_ops drivers/acpi: convert seqno to use seqnum_ops drivers/acpi/apei: convert seqno to seqnum_ops drivers/staging/rtl8723bs: convert event_seq to use seqnum_ops drivers/staging/rtl8188eu: convert event_seq to use seqnum_ops
kobject: convert uevent_seqnum to seqnum_ops

 Documentation/core-api/index.rst              |   1 +
 Documentation/core-api/seqnum_ops.rst         |  62 ++++++++
 MAINTAINERS                                   |   8 ++
 drivers/acpi/acpi_extlog.c                    |   8 +-
 drivers/acpi/apei/ghes.c                      |   8 +-
 drivers/staging/rtl8188eu/core/rtw_mlme_ext.c |  23 ++-
 .../staging/rtl8188eu/include/rtw_mlme_ext.h  |   3 +-
 drivers/staging/rtl8723bs/core/rtw_cmd.c      |   3 +-
 drivers/staging/rtl8723bs/core/rtw_mlme_ext.c |  33 +++--
 drivers/staging/rtl8723bs/include/rtw_cmd.h   |   3 +-
 .../staging/rtl8723bs/include/rtw_mlme_ext.h  |   3 +-
 include/linux/kobject.h                       |   3 +-
 include/linux/seqnum_ops.h                    | 131 +++++++++++++++++
 kernel/ksysfs.c                               |   3 +-
 lib/Kconfig                                   |   9 ++
 lib/Makefile                                  |   1 +
 lib/kobject_uevent.c                          |   9 +-
 lib/test_seqnum_ops.c                         | 133 ++++++++++++++++++
 tools/testing/selftests/lib/Makefile          |   1 +
 tools/testing/selftests/lib/config            |   1 +
 .../testing/selftests/lib/test_seqnum_ops.sh  |  10 ++
 21 files changed, 423 insertions(+), 33 deletions(-)
 create mode 100644 Documentation/core-api/seqnum_ops.rst
 create mode 100644 include/linux/seqnum_ops.h
 create mode 100644 lib/test_seqnum_ops.c
 create mode 100755 tools/testing/selftests/lib/test_seqnum_ops.sh

2.27.0