mainline inclusion
from mainline-5.12-rc1
commit c6458e72
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=c6458e72f6fd6ac7e390da0d9abe8446084886e5

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

When the buffer is too small to contain the input string, these helpers
return the length of the buffer, not the length of the original string.
This tries to make the docs totally clear about that, since "the length
of the [copied ]string" could also refer to the length of the input.
Signed-off-by: NBrendan Jackman <jackmanb@google.com>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NKP Singh <kpsingh@kernel.org>
Acked-by: NYonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210112123422.2011234-1-jackmanb@google.com
(cherry picked from commit c6458e72)
Signed-off-by: NWang Yufen <wangyufen@huawei.com>