Messages in this thread | | | Date | Wed, 15 Dec 2021 17:38:11 +0000 | Subject | Re: [PATCH v3] cgroup/bpf: fast path skb BPF filtering | From | Pavel Begunkov <> |
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On 12/15/21 16:40, Jakub Kicinski wrote: > On Wed, 15 Dec 2021 14:49:18 +0000 Pavel Begunkov wrote: >> +static inline bool >> +__cgroup_bpf_prog_array_is_empty(struct cgroup_bpf *cgrp_bpf, >> + enum cgroup_bpf_attach_type type) >> +{ >> + struct bpf_prog_array *array = rcu_access_pointer(cgrp_bpf->effective[type]); >> + >> + return array == &bpf_empty_prog_array.hdr; >> +} >> + >> +#define CGROUP_BPF_TYPE_ENABLED(sk, atype) \ >> +({ \ >> + struct cgroup *__cgrp = sock_cgroup_ptr(&(sk)->sk_cgrp_data); \ >> + \ >> + !__cgroup_bpf_prog_array_is_empty(&__cgrp->bpf, (atype)); \ >> +}) >> + > >> diff --git a/include/linux/bpf.h b/include/linux/bpf.h >> index e7a163a3146b..0d2195c6fb2a 100644 >> --- a/include/linux/bpf.h >> +++ b/include/linux/bpf.h >> @@ -1161,6 +1161,19 @@ struct bpf_prog_array { >> struct bpf_prog_array_item items[]; >> }; >> >> +struct bpf_empty_prog_array { >> + struct bpf_prog_array hdr; >> + struct bpf_prog *null_prog; >> +}; >> + >> +/* to avoid allocating empty bpf_prog_array for cgroups that >> + * don't have bpf program attached use one global 'bpf_empty_prog_array' >> + * It will not be modified the caller of bpf_prog_array_alloc() >> + * (since caller requested prog_cnt == 0) >> + * that pointer should be 'freed' by bpf_prog_array_free() >> + */ >> +extern struct bpf_empty_prog_array bpf_empty_prog_array; > > mumble mumble, this adds more "fun" dependencies [1] Maybe I'm going
Header dependencies? It's declared right after struct bpf_prog_array, and the other member is a pointer, so not sure what can go wrong.
> about this all wrong, maybe I should be pulling out struct cgroup_bpf > so that cgroup.h does not need bpf-cgroup, not breaking bpf <-> bpf-cgroup. > Alexei, WDYT? > > [1] https://lore.kernel.org/all/20211215061916.715513-2-kuba@kernel.org/ >
-- Pavel Begunkov
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