[PATCHv2 perf/core 0/7] Libbpf improvements

[Joe Stringer <joe@ovn.org>]

Patch 1 fixes an issue when using drastically different BPF map definitions
inside ELFs from a client using libbpf, vs the map definition libbpf uses.

Patches 2-4 add some simple, useful helper functions for setting prog type
and retrieving libbpf errors without depending on kernel headers from
userspace programs.

Patches 5-7 add a new pinning functionality for maps, programs, and objects.
Library users may call bpf_map__pin(map, path) or bpf_program__pin(prog, path)
to pin maps and programs separately, or use bpf_object__pin(obj, path) to
pin all maps and programs from the BPF object to the path. The map and program
variations require a full path where it will be pinned in the filesystem,
and the object variation will create directories "maps/" and "progs/" under
the specified path, then mount each map and program under those subdirectories.

---
v1: Initial post.
v2: Wang Nan provided improvements to patch 1.
    Dropped patch 2 from v1.
    Added acks for acked patches.
    Split the bpf_obj__pin() to also provide map / program pinning APIs.
    Allow users to provide full filesystem path (don't autodetect/mount BPFFS).

Joe Stringer (7):
  tools lib bpf: Fix map offsets in relocation
  tools lib bpf: Define prog_type fns with macro
  tools lib bpf: Add set/is helpers for all prog types
  tools lib bpf: Add libbpf_get_error()
  tools lib bpf: Add bpf_program__pin()
  tools lib bpf: Add bpf_map__pin()
  tools lib bpf: Add bpf_object__pin()

 tools/lib/bpf/libbpf.c  | 240 ++++++++++++++++++++++++++++++++++++++++++------
 tools/lib/bpf/libbpf.h  |  17 +++-
 tools/perf/tests/llvm.c |   2 +-
 3 files changed, 229 insertions(+), 30 deletions(-)

-- 
2.11.0