Andrii Nakryiko says:
====================
Implement error reporting changes discussed in "Libbpf: the road to v1.0"
([0]) document.
Libbpf gets a new API, libbpf_set_strict_mode() which accepts a set of flags
that turn on a set of libbpf 1.0 changes, that might be potentially breaking.
It's possible to opt-in into all current and future 1.0 features by specifying
LIBBPF_STRICT_ALL flag.
When some of the 1.0 "features" are requested, libbpf APIs might behave
differently. In this patch set a first set of changes are implemented, all
related to the way libbpf returns errors. See individual patches for details.
Patch #1 adds a no-op libbpf_set_strict_mode() functionality to enable
updating selftests.
Patch #2 gets rid of all the bad code patterns that will break in libbpf 1.0
(exact -1 comparison for low-level APIs, direct IS_ERR() macro usage to check
pointer-returning APIs for error, etc). These changes make selftest work in
both legacy and 1.0 libbpf modes. Selftests also opt-in into 100% libbpf 1.0
mode to automatically gain all the subsequent changes, which will come in
follow up patches.
Patch #3 streamlines error reporting for low-level APIs wrapping bpf() syscall.
Patch #4 streamlines errors for all the rest APIs.
Patch #5 ensures that BPF skeletons propagate errors properly as well, as
currently on error some APIs will return NULL with no way of checking exact
error code.
[0] https://docs.google.com/document/d/1UyjTZuPFWiPFyKk1tV5an11_iaRuec6U-ZESZ54nNTY
v1->v2:
- move libbpf_set_strict_mode() implementation to patch #1, where it belongs
(Alexei);
- add acks, slight rewording of commit messages.
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>