mainline inclusion
from mainline-5.14-rc1
commit f12b6543
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I5EUVD
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f12b654327283d158de0af170943ec5dd8cd02e5

-------------------------------------------------

Ensure that low-level APIs behave uniformly across the libbpf as follows:
  - in case of an error, errno is always set to the correct error code;
  - when libbpf 1.0 mode is enabled with LIBBPF_STRICT_DIRECT_ERRS option to
    libbpf_set_strict_mode(), return -Exxx error value directly, instead of -1;
  - by default, until libbpf 1.0 is released, keep returning -1 directly.

More context, justification, and discussion can be found in "Libbpf: the road
to v1.0" document ([0]).

  [0] https://docs.google.com/document/d/1UyjTZuPFWiPFyKk1tV5an11_iaRuec6U-ZESZ54nNTYSigned-off-by: NAndrii Nakryiko <andrii@kernel.org>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NJohn Fastabend <john.fastabend@gmail.com>
Acked-by: NToke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20210525035935.1461796-4-andrii@kernel.org
(cherry picked from commit f12b6543)
Signed-off-by: NWang Yufen <wangyufen@huawei.com>