RE: [PATCH bpf-next 2/3] bpf: mostly decouple jump history management from is_state_visited()

[John Fastabend <john.fastabend@gmail.com>]

Andrii Nakryiko wrote:
> Jump history updating and state equivalence checks are conceptually
> independent, so move push_jmp_history() out of is_state_visited(). Also
> make a decision whether to perform state equivalence checks or not one
> layer higher in do_check(), keeping is_state_visited() unconditionally
> performing state checks.
> 
> push_jmp_history() should be performed after state checks. There is just
> one small non-uniformity. When is_state_visited() finds already
> validated equivalent state, it propagates precision marks to current
> state's parent chain. For this to work correctly, jump history has to be
> updated, so is_state_visited() is doing that internally.
> 
> But if no equivalent verified state is found, jump history has to be
> updated in a newly cloned child state, so is_jmp_point()
> + push_jmp_history() is performed after is_state_visited() exited with
> zero result, which means "proceed with validation".
> 
> This change has no functional changes. It's not strictly necessary, but
> feels right to decouple these two processes.
> 
> Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
> ---

Acked-by: John Fastabend <john.fastabend@gmail.com>