On Thu, Sep 14, 2023 at 9:55 AM Larysa Zaremba <larysa.zaremba@xxxxxxxxx> wrote: > > On Thu, Sep 14, 2023 at 09:29:57AM -0700, Stanislav Fomichev wrote: > > On 09/14, Larysa Zaremba wrote: > > > There is no fundamental reason, why multi-buffer XDP and XDP kfunc RX hints > > > cannot coexist in a single program. > > > > > > Allow those features to be used together by modifying the flags conditions. > > > > > > Suggested-by: Stanislav Fomichev <sdf@xxxxxxxxxx> > > > Link: https://lore.kernel.org/bpf/CAKH8qBuzgtJj=OKMdsxEkyML36VsAuZpcrsXcyqjdKXSJCBq=Q@xxxxxxxxxxxxxx/ > > > Signed-off-by: Larysa Zaremba <larysa.zaremba@xxxxxxxxx> > > > --- > > > kernel/bpf/offload.c | 6 +++++- > > > 1 file changed, 5 insertions(+), 1 deletion(-) > > > > > > diff --git a/kernel/bpf/offload.c b/kernel/bpf/offload.c > > > index ee35f33a96d1..43aded96c79b 100644 > > > --- a/kernel/bpf/offload.c > > > +++ b/kernel/bpf/offload.c > > > @@ -232,7 +232,11 @@ int bpf_prog_dev_bound_init(struct bpf_prog *prog, union bpf_attr *attr) > > > attr->prog_type != BPF_PROG_TYPE_XDP) > > > return -EINVAL; > > > > > > - if (attr->prog_flags & ~BPF_F_XDP_DEV_BOUND_ONLY) > > > + if (attr->prog_flags & ~(BPF_F_XDP_DEV_BOUND_ONLY | BPF_F_XDP_HAS_FRAGS)) > > > + return -EINVAL; > > > + > > > > [..] > > > > > + if (attr->prog_flags & BPF_F_XDP_HAS_FRAGS && > > > + !(attr->prog_flags & BPF_F_XDP_DEV_BOUND_ONLY)) > > > return -EINVAL; > > > > Any reason we have 'attr->prog_flags & BPF_F_XDP_HAS_FRAGS' part here? > > Seems like doing '!(attr->prog_flags & BPF_F_XDP_DEV_BOUND_ONLY)' should > > be enough, right? We only want to bail out here when BPF_F_XDP_DEV_BOUND_ONLY > > is not set and we don't really care whether BPF_F_XDP_HAS_FRAGS is set > > or not at this point. > > If !(attr->prog_flags & BPF_F_XDP_DEV_BOUND_ONLY) at this point, program could > be requesting offload. > > Now I have thought about those conditions once more and they could be reduced to > this: > > if (attr->prog_flags & ~(BPF_F_XDP_DEV_BOUND_ONLY) && > attr->prog_flags != (BPF_F_XDP_DEV_BOUND_ONLY | BPF_F_XDP_HAS_FRAGS)) > return -EINVAL; > > What do you think? Ah, so this check is here to protect against the mbuf+offloaded combination? (looking at that other thread with Maciej) Let's keep your current way with two separate checks, but let's add your "/* Frags are allowed only if program is dev-bound-only, but not if it is requesting bpf offload. */" as a comment to the second check?
