[PATCH bpf-next v2 0/5] bpf: compute btf_ids at build time for btf_iter

[Yonghong Song <yhs@fb.com>]

Commit 5a2798ab32ba
("bpf: Add BTF_ID_LIST/BTF_ID/BTF_ID_UNUSED macros")
implemented a mechanism to compute btf_ids at kernel build
time which can simplify kernel implementation and reduce
runtime overhead by removing in-kernel btf_id calculation.

This patch set tried to use this mechanism to compute
btf_ids for bpf_skc_to_*() helpers and for btf_id_or_null ctx
arguments specified during bpf iterator registration.
Please see individual patch for details.

Changelogs:
  v1 -> v2:
    - v1 ([1]) is only for bpf_skc_to_*() helpers. This version
      expanded it to cover ctx btf_id_or_null arguments
    - abandoned the change of "extern u32 name[]" to
      "static u32 name[]" for BPF_ID_LIST local "name" definition.
      gcc 9 incurred a compilation error.

 [1]: https://lore.kernel.org/bpf/20200717184706.3476992-1-yhs@fb.com/T

Yonghong Song (5):
  bpf: compute bpf_skc_to_*() helper socket btf ids at build time
  tools/bpf: sync btf_ids.h to tools
  bpf: add BTF_ID_LIST_GLOBAL in btf_ids.h
  bpf: make btf_sock_ids global
  bpf: net: use precomputed btf_id for bpf iterators

 include/linux/bpf.h                           |  5 +-
 include/linux/btf_ids.h                       | 40 +++++++++++++--
 kernel/bpf/btf.c                              |  6 +--
 kernel/bpf/map_iter.c                         |  7 ++-
 kernel/bpf/task_iter.c                        | 12 ++++-
 net/core/filter.c                             | 49 ++----------------
 net/ipv4/tcp_ipv4.c                           |  4 +-
 net/ipv4/udp.c                                |  4 +-
 net/ipv6/route.c                              |  7 ++-
 net/netlink/af_netlink.c                      |  7 ++-
 tools/include/linux/btf_ids.h                 | 51 +++++++++++++++++--
 .../selftests/bpf/prog_tests/resolve_btfids.c | 34 ++++++++++---
 12 files changed, 153 insertions(+), 73 deletions(-)

-- 
2.24.1