This patch series introduces BPF iterators for wakeup_source, enabling
BPF programs to efficiently traverse a device's wakeup sources.

Currently, inspecting wakeup sources typically involves reading interfaces
like /sys/class/wakeup/* or debugfs. The repeated syscalls to query the
sysfs nodes is inefficient, as there can be hundreds of wakeup_sources, and
each wakeup source have multiple stats, with one sysfs node per stat.
debugfs is unstable and insecure.

This series implements two types of iterators:
1. Standard BPF Iterator: Allows creating a BPF link to iterate over
   wakeup sources
2. Open-coded Iterator: Enables the use of wakeup_source iterators directly
   within BPF programs

Both iterators utilize pre-existing APIs wakeup_sources_walk_* to traverse
over the SRCU that backs the list of wakeup_sources.

Samuel Wu (4):
  bpf: Add wakeup_source iterator
  bpf: Open coded BPF for wakeup_sources
  selftests/bpf: Add tests for wakeup_sources
  selftests/bpf: Open coded BPF wakeup_sources test

 kernel/bpf/Makefile                           |   1 +
 kernel/bpf/helpers.c                          |   3 +
 kernel/bpf/wakeup_source_iter.c               | 137 ++++++++
 .../testing/selftests/bpf/bpf_experimental.h  |   5 +
 tools/testing/selftests/bpf/config            |   1 +
 .../bpf/prog_tests/wakeup_source_iter.c       | 323 ++++++++++++++++++
 .../selftests/bpf/progs/wakeup_source_iter.c  | 117 +++++++
 7 files changed, 587 insertions(+)
 create mode 100644 kernel/bpf/wakeup_source_iter.c
 create mode 100644 tools/testing/selftests/bpf/prog_tests/wakeup_source_iter.c
 create mode 100644 tools/testing/selftests/bpf/progs/wakeup_source_iter.c

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2.52.0.177.g9f829587af-goog