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Wed, 14 Oct 2026 14:45:09 -0700 (PDT) From: Jiri Olsa X-Google-Original-From: Jiri Olsa Date: Wed, 14 Oct 2026 23:45:07 +0200 To: Leon Hwang Cc: bpf@vger.kernel.org, Alexei Starovoitov , Daniel Borkmann , John Fastabend , Andrii Nakryiko , Eduard Zingerman , Kumar Kartikeya Dwivedi , Martin KaFai Lau , Song Liu , Yonghong Song , Emil Tsalapatis , Ihor Solodrai , Quentin Monnet , Shuah Khan , Mykyta Yatsenko , Avinash Duduskar , Anton Protopopov , Amery Hung , Jordan Rife , Rong Tao , Eyal Birger , Pu Lehui , Jingguo Tan , Lin Ma , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH bpf-next v2 11/21] bpf: Add tracing_multi link support for bpf progs Message-ID: References: <20261012154024.29423-1-leon.hwang@linux.dev> <20261012154024.29423-12-leon.hwang@linux.dev> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261012154024.29423-12-leon.hwang@linux.dev> On Mon, Oct 12, 2026 at 11:40:13PM +0800, Leon Hwang wrote: SNIP > @@ -3787,64 +3796,129 @@ static const struct bpf_link_ops bpf_tracing_multi_link_lops = { > #endif > }; > > -static int ids_cmp_r(const void *pa, const void *pb, const void *priv __maybe_unused) > +struct tracing_multi_sort_data { > + u64 *keys; > + struct bpf_prog **progs; > + u32 *ids; > + u64 *cookies; > +}; > + > +static int keys_cmp_r(const void *pa, const void *pb, const void *priv __maybe_unused) > { > - u32 a = *(u32 *) pa; > - u32 b = *(u32 *) pb; I think you could just s/32/64/ and keep the rest in here and have simpler diff > + const u64 *key_a = pa, *key_b = pb; > > - return (a > b) - (a < b); > + return (*key_a > *key_b) - (*key_a < *key_b); > } > > -static void ids_swap_r(void *a, void *b, int size __maybe_unused, > - const void *priv __maybe_unused) > +static void keys_swap_r(void *a, void *b, int size __maybe_unused, > + const void *priv __maybe_unused) > { > + const struct tracing_multi_sort_data *data = priv; > + struct bpf_prog **prog_a, **prog_b; > u64 *cookie_a, *cookie_b, *cookies; > - u32 *id_a = a, *id_b = b, *ids; > - void **data = (void **) priv; > + u64 *key_a = a, *key_b = b, *keys; > + u32 *id_a, *id_b, *ids; > + > + keys = data->keys; > + ids = data->ids; > + cookies = data->cookies; > + id_a = ids + (key_a - keys); > + id_b = ids + (key_b - keys); > > - ids = data[0]; > - cookies = data[1]; > + if (data->progs) { nit, let's unify with the rest of the code and have progs variable for data->progs ? SNIP > - err = check_dup_ids(ids, cookies, cnt); > + keys = kvmalloc_objs(*keys, cnt); > + if (!keys) { > + err = -ENOMEM; > + goto error; > + } > + > + for (int i = 0; i < cnt; i++) > + keys[i] = bpf_trampoline_compute_key(progs ? progs[i] : NULL, btf, ids[i]); > + > + err = check_dup_keys(keys, progs, ids, cookies, cnt); > if (err) > goto error; > > @@ -3908,19 +4022,32 @@ int bpf_tracing_multi_attach(struct bpf_prog *prog, const union bpf_attr *attr) > link->nodes_cnt = cnt; > link->cookies = cookies; > link->fexits = fexits; > + link->tgt_progs = progs; > + link->pokes = pokes; > > - err = bpf_trampoline_multi_attach(prog, ids, link); > + if (progs) > + err = bpf_trampoline_multi_prog_attach(prog, ids, keys, link); you need keys computed ahead for dups check, so let's the above bpf_trampoline_compute_key calls be the single place we compute keys and pass keys to bpf_trampoline_multi_attach below as well? > + else > + err = bpf_trampoline_multi_attach(prog, ids, link); nit, let's add empty line in here? > kvfree(ids); > + kvfree(keys); > + kvfree(fds); > if (err) { > + bpf_put_progs(progs, cnt); > bpf_link_cleanup(&link_primer); > return err; > } > return bpf_link_settle(&link_primer); thanks, jirka