mainline inclusion
from mainline-5.14-rc2
commit af0efa05
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=af0efa050caa66e8f304c42c94c76cb6c480cb7e

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

The update to streamline libbpf error reporting intended to change all
functions to return the errno as a negative return value if
LIBBPF_STRICT_DIRECT_ERRS is set. However, if the flag is *not* set, the
return value changes for the two functions that were already returning a
negative errno unconditionally: bpf_link__unpin() and perf_buffer__poll().

This is a user-visible API change that breaks applications; so let's revert
these two functions back to unconditionally returning a negative errno
value.

Fixes: e9fc3ce9 ("libbpf: Streamline error reporting for high-level APIs")
Signed-off-by: NToke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: NAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210706122355.236082-1-toke@redhat.com
(cherry picked from commit af0efa05)
Signed-off-by: NWang Yufen <wangyufen@huawei.com>