Wireshark-dev: [Wireshark-dev] Replacing wmem_packet_scope() with pinfo->pool?

From: Evan Huus <eapache@xxxxxxxxx>
Date: Mon, 12 Jul 2021 11:52:22 -0400
I've been thinking recently about starting the process of getting rid
of the "global" wmem scope methods (wmem_packet_scope,
wmem_file_scope, etc) in favour of passing them around in arguments
(or in pinfo, or something). This would let us drop a bunch of
in-scope/out-of-scope tracking and assertion, as well as make the code
more amenable to future refactors like (potentially) concurrency.

At a first glance, we already have pinfo->pool which maintains the
lifetime of the packet_info object. As far as I can reason, this is
almost/effectively the same as the existing wmem_packet_scope - it
gets cleaned up later in the dissection flow, but there's still only
ever one which gets reused for each packet.

Is this correct? If so, does it make sense to start replacing
`wmem_packet_scope()` calls with `pinfo->pool` when pinfo is already
in scope?

Thanks,
Evan