[v3,bpf-next,0/9] introduce support for XDP programs in CPUMAP

Similar to what David Ahern proposed in [1] for DEVMAPs, introduce the
capability to attach and run a XDP program to CPUMAP entries.
The idea behind this feature is to add the possibility to define on which CPU
run the eBPF program if the underlying hw does not support RSS.
I respin patch 1/6 from a previous series sent by David [2].
The functionality has been tested on Marvell Espressobin, i40e and mlx5.
Detailed tests results can be found here:
https://github.com/xdp-project/xdp-project/blob/master/areas/cpumap/cpumap04-map-xdp-prog.org

Changes since v2:
- improved comments
- fix return value in xdp_convert_buff_to_frame
- added patch 1/9: "cpumap: use non-locked version __ptr_ring_consume_batched"
- do not run kmem_cache_alloc_bulk if all frames have been consumed by the XDP
  program attached to the CPUMAP entry
- removed bpf_trace_printk in kselftest

Changes since v1:
- added performance test results
- added kselftest support
- fixed memory accounting with page_pool
- extended xdp_redirect_cpu_user.c to load an external program to perform
  redirect
- reported ifindex to attached eBPF program
- moved bpf_cpumap_val definition to include/uapi/linux/bpf.h

[1] https://patchwork.ozlabs.org/project/netdev/cover/20200529220716.75383-1-dsahern@kernel.org/
[2] https://patchwork.ozlabs.org/project/netdev/patch/20200513014607.40418-2-dsahern@kernel.org/

David Ahern (1):
  net: Refactor xdp_convert_buff_to_frame

Jesper Dangaard Brouer (1):
  cpumap: use non-locked version __ptr_ring_consume_batched

Lorenzo Bianconi (7):
  samples/bpf: xdp_redirect_cpu_user: do not update bpf maps in option
    loop
  cpumap: formalize map value as a named struct
  bpf: cpumap: add the possibility to attach an eBPF program to cpumap
  bpf: cpumap: implement XDP_REDIRECT for eBPF programs attached to map
    entries
  libbpf: add SEC name for xdp programs attached to CPUMAP
  samples/bpf: xdp_redirect_cpu: load a eBPF program on cpumap
  selftest: add tests for XDP programs in CPUMAP entries

 include/linux/bpf.h                           |   6 +
 include/net/xdp.h                             |  41 ++--
 include/trace/events/xdp.h                    |  16 +-
 include/uapi/linux/bpf.h                      |  14 ++
 kernel/bpf/cpumap.c                           | 160 +++++++++++---
 net/core/dev.c                                |   8 +
 samples/bpf/xdp_redirect_cpu_kern.c           |  25 ++-
 samples/bpf/xdp_redirect_cpu_user.c           | 208 ++++++++++++++++--
 tools/include/uapi/linux/bpf.h                |  14 ++
 tools/lib/bpf/libbpf.c                        |   2 +
 .../bpf/prog_tests/xdp_cpumap_attach.c        |  70 ++++++
 .../bpf/progs/test_xdp_with_cpumap_helpers.c  |  40 ++++
 12 files changed, 532 insertions(+), 72 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/xdp_cpumap_attach.c
 create mode 100644 tools/testing/selftests/bpf/progs/test_xdp_with_cpumap_helpers.c