This patch set clean up some code logic related with managing subprog
information.
Part of the set are inspried by Edwin's code in his RFC:
"bpf/verifier: subprog/func_call simplifications"
but with clearer separation so it could be easier to review.
- Path 1 unifies main prog and subprogs. All of them are registered in
env->subprog_starts.
- After patch 1, it is clear that subprog_starts and subprog_stack_depth
could be merged as both of them now have main and subprog unified.
Patch 2 therefore does the merge, all subprog information are centred
at bpf_subprog_info.
- Patch 3 goes further to introduce a new fake "exit" subprog which
serves as an ending marker to the subprog list. We could then turn the
following code snippets across verifier:
if (env->subprog_cnt == cur_subprog + 1)
subprog_end = insn_cnt;
else
subprog_end = env->subprog_info[cur_subprog + 1].start;
into:
subprog_end = env->subprog_info[cur_subprog + 1].start;
There is no functional change by this patch set.
No bpf selftest (both non-jit and jit) regression found after this set.
v2:
- fixed adjust_subprog_starts to also update fake "exit" subprog start.
- for John's suggestion on renaming subprog to prog, I could work on
a follow-up patch if it is recognized as worth the change.
Jiong Wang (3):
bpf: unify main prog and subprog
bpf: centre subprog information fields
bpf: add faked "ending" subprog
include/linux/bpf_verifier.h | 9 ++--
kernel/bpf/verifier.c | 121 ++++++++++++++++++++++---------------------
2 files changed, 67 insertions(+), 63 deletions(-)
--
2.7.4
