[PATCH v6 bpf-next 0/3] Add a new API libbpf_num_possible_cpus()

[Hechao Li <hechaol@fb.com>]

Getting number of possible CPUs is commonly used for per-CPU BPF maps
and perf_event_maps. Add a new API libbpf_num_possible_cpus() that
helps user with per-CPU related operations and remove duplicate
implementations in bpftool and selftests.

v2: Save errno before calling pr_warning in case it is changed.
v3: Make sure libbpf_num_possible_cpus never returns 0 so that user only
    has to check if ret value < 0.
v4: Fix error code when reading 0 bytes from possible CPU file.
v5: Fix selftests compliation issue.
v6: Split commit to reuse libbpf_num_possible_cpus() into two commits:
    One commit to remove bpf_util.h from test BPF C programs.
    One commit to reuse libbpf_num_possible_cpus() in bpftools 
    and bpf_util.h.


Hechao Li (3):
  bpf: add a new API libbpf_num_possible_cpus()
  selftests/bpf: remove bpf_util.h from BPF C progs
  bpf: use libbpf_num_possible_cpus internally

 tools/bpf/bpftool/common.c                    | 53 ++---------------
 tools/lib/bpf/libbpf.c                        | 57 +++++++++++++++++++
 tools/lib/bpf/libbpf.h                        | 16 ++++++
 tools/lib/bpf/libbpf.map                      |  1 +
 tools/testing/selftests/bpf/bpf_endian.h      |  1 +
 tools/testing/selftests/bpf/bpf_util.h        | 37 ++----------
 .../selftests/bpf/progs/sockmap_parse_prog.c  |  1 -
 .../bpf/progs/sockmap_tcp_msg_prog.c          |  2 +-
 .../bpf/progs/sockmap_verdict_prog.c          |  1 -
 .../selftests/bpf/progs/test_sysctl_prog.c    |  5 +-
 10 files changed, 90 insertions(+), 84 deletions(-)

-- 
2.17.1