On Wed, Mar 10, 2021 at 10:59 PM Björn Töpel <bjorn.topel@xxxxxxxxx> wrote: > > On 2021-03-11 01:06, Jonathan Lemon wrote: > > On Wed, Mar 10, 2021 at 09:09:29AM +0100, Björn Töpel wrote: > >> From: Björn Töpel <bjorn.topel@xxxxxxxxx> > >> > >> The only user of libbpf_util.h is xsk.h. Move the barriers to xsk.h, > >> and remove libbpf_util.h. The barriers are used as an implementation > >> detail, and should not be considered part of the stable API. > > > > Does that mean that anything else which uses the same type of > > shared rings (bpf ringbuffer, io_uring, zctap) have to implement > > the same primitives that xsk.h has? > > > > Jonathan, there's a longer explanation on back-/forward-compatibility in > the commit message [1]. Again, this is for the XDP socket rings, so I > wont comment on the other rings. I would not assume compatibility > between different rings (e.g. the bpf ringbuffer and XDP sockets rings), > not even prior the barrier change. > > BPF ringbuf is using smp_store_release()/smp_load_acquire(), which are coming from asm/barrier.h. But libbpf abstracts all the low-level details, so users don't have to use such low-level primitives directly. > Björn > > [1] > https://lore.kernel.org/bpf/20210305094113.413544-2-bjorn.topel@xxxxxxxxx/ >
