From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4C4B4C6FD1E for ; Tue, 7 Mar 2023 23:34:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230195AbjCGXeZ (ORCPT ); Tue, 7 Mar 2023 18:34:25 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45802 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229995AbjCGXdz (ORCPT ); Tue, 7 Mar 2023 18:33:55 -0500 Received: from mx0b-00082601.pphosted.com (mx0b-00082601.pphosted.com [67.231.153.30]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 861C29927D for ; Tue, 7 Mar 2023 15:33:28 -0800 (PST) Received: from pps.filterd (m0109332.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 327M8Tgc025664 for ; Tue, 7 Mar 2023 15:33:27 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=meta.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : content-type; s=s2048-2021-q4; bh=gcXRECaNSgbweyGX4I0Sf0s4Z9QAlWS1aBfJ44Wrmls=; b=TMwg1LDg/i1F/CWGnKW/gxGcwhSGplyKF5OEouqgyt4LBPvoqPDEoxNHzhWdUVPHCoGx 7AdP0p03uyYihFyeFiuEJgcp4nfSstBgKPDARGo//4uOlStEyfyxQ88lxCaNuovaHfhq PBD/LpCxOjw+g8OSlPSEMlD/S+c/voiFj5q8clq3Z3kaPmWtQTH0RqXPRQqrCKrvToWa G/DAGkL/49UUHXlswdqbbKSplF5e/5kQhcvf0aq8Z+rzcUDxBD0qB2Tk0G/BLo964SEV 0G9fd9Er6LdqkTsT7Qnb5Jh3HJtcw/plALZe7aNbk4e2k8V3s6yVJx3tBr9lZUOGAPTh eg== Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 3p63bvdb6u-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Tue, 07 Mar 2023 15:33:27 -0800 Received: from twshared33736.38.frc1.facebook.com (2620:10d:c085:208::f) by mail.thefacebook.com (2620:10d:c085:21d::5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.17; Tue, 7 Mar 2023 15:33:26 -0800 Received: by devbig931.frc1.facebook.com (Postfix, from userid 460691) id 472936C7C9BD; Tue, 7 Mar 2023 15:33:13 -0800 (PST) From: Kui-Feng Lee To: , , , , , , CC: Kui-Feng Lee Subject: [PATCH bpf-next v4 5/9] libbpf: Create a bpf_link in bpf_map__attach_struct_ops(). Date: Tue, 7 Mar 2023 15:33:03 -0800 Message-ID: <20230307233307.3626875-6-kuifeng@meta.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230307233307.3626875-1-kuifeng@meta.com> References: <20230307233307.3626875-1-kuifeng@meta.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-FB-Internal: Safe Content-Type: text/plain X-Proofpoint-GUID: K-tkPzIPvDMOYNuc7NLsbSS377jnAsxs X-Proofpoint-ORIG-GUID: K-tkPzIPvDMOYNuc7NLsbSS377jnAsxs X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.219,Aquarius:18.0.942,Hydra:6.0.573,FMLib:17.11.170.22 definitions=2023-03-07_16,2023-03-07_01,2023-02-09_01 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org bpf_map__attach_struct_ops() was creating a dummy bpf_link as a placeholder, but now it is constructing an authentic one by calling bpf_link_create() if the map has the BPF_F_LINK flag. You can flag a struct_ops map with BPF_F_LINK by calling bpf_map__set_map_flags(). Signed-off-by: Kui-Feng Lee --- tools/lib/bpf/libbpf.c | 84 +++++++++++++++++++++++++++++++----------- 1 file changed, 62 insertions(+), 22 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 35a698eb825d..a67efc3b3763 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -115,6 +115,7 @@ static const char * const attach_type_name[] =3D { [BPF_SK_REUSEPORT_SELECT_OR_MIGRATE] =3D "sk_reuseport_select_or_migrat= e", [BPF_PERF_EVENT] =3D "perf_event", [BPF_TRACE_KPROBE_MULTI] =3D "trace_kprobe_multi", + [BPF_STRUCT_OPS] =3D "struct_ops", }; =20 static const char * const link_type_name[] =3D { @@ -7677,6 +7678,26 @@ static int bpf_object__resolve_externs(struct bpf_= object *obj, return 0; } =20 +static void bpf_map_prepare_vdata(const struct bpf_map *map) +{ + struct bpf_struct_ops *st_ops; + __u32 i; + + st_ops =3D map->st_ops; + for (i =3D 0; i < btf_vlen(st_ops->type); i++) { + struct bpf_program *prog =3D st_ops->progs[i]; + void *kern_data; + int prog_fd; + + if (!prog) + continue; + + prog_fd =3D bpf_program__fd(prog); + kern_data =3D st_ops->kern_vdata + st_ops->kern_func_off[i]; + *(unsigned long *)kern_data =3D prog_fd; + } +} + static int bpf_object_load(struct bpf_object *obj, int extra_log_level, = const char *target_btf_path) { int err, i; @@ -7728,6 +7749,10 @@ static int bpf_object_load(struct bpf_object *obj,= int extra_log_level, const ch btf__free(obj->btf_vmlinux); obj->btf_vmlinux =3D NULL; =20 + for (i =3D 0; i < obj->nr_maps; i++) + if (bpf_map__is_struct_ops(&obj->maps[i])) + bpf_map_prepare_vdata(&obj->maps[i]); + obj->loaded =3D true; /* doesn't matter if successfully or not */ =20 if (err) @@ -11429,22 +11454,34 @@ struct bpf_link *bpf_program__attach(const stru= ct bpf_program *prog) return link; } =20 +struct bpf_link_struct_ops { + struct bpf_link link; + int map_fd; +}; + static int bpf_link__detach_struct_ops(struct bpf_link *link) { + struct bpf_link_struct_ops *st_link; __u32 zero =3D 0; =20 - if (bpf_map_delete_elem(link->fd, &zero)) - return -errno; + st_link =3D container_of(link, struct bpf_link_struct_ops, link); =20 - return 0; + if (st_link->map_fd < 0) { + /* Fake bpf_link */ + if (bpf_map_delete_elem(link->fd, &zero)) + return -errno; + return 0; + } + + /* Doesn't support detaching. */ + return -EOPNOTSUPP; } =20 struct bpf_link *bpf_map__attach_struct_ops(const struct bpf_map *map) { - struct bpf_struct_ops *st_ops; - struct bpf_link *link; - __u32 i, zero =3D 0; - int err; + struct bpf_link_struct_ops *link; + __u32 zero =3D 0; + int err, fd; =20 if (!bpf_map__is_struct_ops(map) || map->fd =3D=3D -1) return libbpf_err_ptr(-EINVAL); @@ -11453,31 +11490,34 @@ struct bpf_link *bpf_map__attach_struct_ops(con= st struct bpf_map *map) if (!link) return libbpf_err_ptr(-EINVAL); =20 - st_ops =3D map->st_ops; - for (i =3D 0; i < btf_vlen(st_ops->type); i++) { - struct bpf_program *prog =3D st_ops->progs[i]; - void *kern_data; - int prog_fd; + /* kern_vdata should be prepared during the loading phase. */ + err =3D bpf_map_update_elem(map->fd, &zero, map->st_ops->kern_vdata, 0)= ; + if (err) { + err =3D -errno; + free(link); + return libbpf_err_ptr(err); + } =20 - if (!prog) - continue; =20 - prog_fd =3D bpf_program__fd(prog); - kern_data =3D st_ops->kern_vdata + st_ops->kern_func_off[i]; - *(unsigned long *)kern_data =3D prog_fd; + if (!(map->def.map_flags & BPF_F_LINK)) { + /* Fake bpf_link */ + link->link.fd =3D map->fd; + link->map_fd =3D -1; + link->link.detach =3D bpf_link__detach_struct_ops; + return &link->link; } =20 - err =3D bpf_map_update_elem(map->fd, &zero, st_ops->kern_vdata, 0); - if (err) { + fd =3D bpf_link_create(map->fd, -1, BPF_STRUCT_OPS, NULL); + if (fd < 0) { err =3D -errno; free(link); return libbpf_err_ptr(err); } =20 - link->detach =3D bpf_link__detach_struct_ops; - link->fd =3D map->fd; + link->link.fd =3D fd; + link->map_fd =3D map->fd; =20 - return link; + return &link->link; } =20 typedef enum bpf_perf_event_ret (*bpf_perf_event_print_t)(struct perf_ev= ent_header *hdr, --=20 2.34.1