On Thu, Jun 12, 2025 at 12:55 AM Alexei Starovoitov <alexei.starovoitov@xxxxxxxxx> wrote: > > On Wed, Jun 11, 2025 at 2:44 PM KP Singh <kpsingh@xxxxxxxxxx> wrote: > > > > On Mon, Jun 9, 2025 at 10:58 PM Alexei Starovoitov > > <alexei.starovoitov@xxxxxxxxx> wrote: [...] > > can add inner maps. I think this is a valid combination as it would > > still retain exclusivity over the outer maps elements. > > I don't follow. > What do you mean by "map can add inner maps ?" Ah, I missed this bit, a program cannot call bpf_map_update_elem on maps of maps and such updates happen only in userspace. Thanks, updated the code. - KP > The exclusivity is a contract between prog<->map. > It doesn't matter whether the map is outer or inner. > The prog cannot add an inner map. > Only the user space can and such inner maps are detached > from anything. > Technically we can come up with a requirement that inner maps > have to have the same prog sha as outer map. > This can be enforced by bpf_map_meta_equal() logic. > But that feels like overkill. > The user space can query prog's sha, create an inner map with > such prog sha and add it to outer map. So the additional check > in bpf_map_meta_equal() would be easy to bypass. > Since so, I would not add such artificial obstacle. > Let all types of maps have this exclusive feature.
