On Sun, May 3, 2020 at 11:26 PM Yonghong Song <yhs@xxxxxx> wrote:
>
> Add bpf_reg_type PTR_TO_BTF_ID_OR_NULL support.
> For tracing/iter program, the bpf program context
> definition, e.g., for previous bpf_map target, looks like
> struct bpf_iter__bpf_map {
> struct bpf_iter_meta *meta;
> struct bpf_map *map;
> };
>
> The kernel guarantees that meta is not NULL, but
> map pointer maybe NULL. The NULL map indicates that all
> objects have been traversed, so bpf program can take
> proper action, e.g., do final aggregation and/or send
> final report to user space.
>
> Add btf_id_or_null_non0_off to prog->aux structure, to
> indicate that if the context access offset is not 0,
> set to PTR_TO_BTF_ID_OR_NULL instead of PTR_TO_BTF_ID.
> This bit is set for tracing/iter program.
>
> Signed-off-by: Yonghong Song <yhs@xxxxxx>
> ---
LGTM.
Acked-by: Andrii Nakryiko <andriin@xxxxxx>
> include/linux/bpf.h | 2 ++
> kernel/bpf/btf.c | 5 ++++-
> kernel/bpf/verifier.c | 16 ++++++++++++----
> 3 files changed, 18 insertions(+), 5 deletions(-)
>
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