From patchwork Wed Mar 8 00:50:46 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kui-Feng Lee X-Patchwork-Id: 13165035 X-Patchwork-Delegate: bpf@iogearbox.net 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 B90AAC6FA99 for ; Wed, 8 Mar 2023 00:51:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229605AbjCHAvL (ORCPT ); Tue, 7 Mar 2023 19:51:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54250 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229574AbjCHAvK (ORCPT ); Tue, 7 Mar 2023 19:51:10 -0500 Received: from mx0a-00082601.pphosted.com (mx0a-00082601.pphosted.com [67.231.145.42]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 315D8A9DEE for ; Tue, 7 Mar 2023 16:51:08 -0800 (PST) Received: from pps.filterd (m0044010.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 32805C3V001603 for ; Tue, 7 Mar 2023 16:51:08 -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=Vmh4sckhr1JnJXdL7JYiz7yy6wpia1wiGhnKjRG31ng=; b=WutrvywNHIZhmGl30vih/2O41EIDYxjArhehVUTXSS/lChYtcK+12EyCCUyJRMu2lF1o oDbC6OQxqebs7lXZRxnJjwbT6Ing3RQC6jXspVGOme8JbQG29HGj9Nu/foxHU0hmcWkr vlew+Ac1Emy4RQvvgRtbhnh0K+Rdmdz2ZXCg82ffLnSwQZ0f90lEhNLxE3AokfGuZyCK 1ZPTYxMJl6pJcomc8I06i33EpfTI31vnk3lLcw7cQPeBDXHwz+R3dbCqOpPtDRQdXUXD rYCR7E6+zw1Mu0nS84hPhwtmBoohz2bHltHZ3gYda/fi3qwfo3Oe7xe1OGLhlqeDmF0N GA== Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 3p6fgp071f-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Tue, 07 Mar 2023 16:51:07 -0800 Received: from twshared52565.14.frc2.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:83::6) 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 16:51:05 -0800 Received: by devbig931.frc1.facebook.com (Postfix, from userid 460691) id 9066B6C92E1A; Tue, 7 Mar 2023 16:50:54 -0800 (PST) From: Kui-Feng Lee To: , , , , , , CC: Kui-Feng Lee Subject: [PATCH bpf-next v5 4/8] libbpf: Create a bpf_link in bpf_map__attach_struct_ops(). Date: Tue, 7 Mar 2023 16:50:46 -0800 Message-ID: <20230308005050.255859-5-kuifeng@meta.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230308005050.255859-1-kuifeng@meta.com> References: <20230308005050.255859-1-kuifeng@meta.com> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-GUID: iTaxcSRCIo8CzB8KpkU-LXJ_VmZTBjoG X-Proofpoint-ORIG-GUID: iTaxcSRCIo8CzB8KpkU-LXJ_VmZTBjoG X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.254,Aquarius:18.0.942,Hydra:6.0.573,FMLib:17.11.170.22 definitions=2023-03-07_18,2023-03-07_01,2023-02-09_01 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net 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 a557718401e4..f70b55c0f40e 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -116,6 +116,7 @@ static const char * const attach_type_name[] = { [BPF_SK_REUSEPORT_SELECT_OR_MIGRATE] = "sk_reuseport_select_or_migrate", [BPF_PERF_EVENT] = "perf_event", [BPF_TRACE_KPROBE_MULTI] = "trace_kprobe_multi", + [BPF_STRUCT_OPS] = "struct_ops", }; static const char * const link_type_name[] = { @@ -7677,6 +7678,26 @@ static int bpf_object__resolve_externs(struct bpf_object *obj, return 0; } +static void bpf_map_prepare_vdata(const struct bpf_map *map) +{ + struct bpf_struct_ops *st_ops; + __u32 i; + + st_ops = map->st_ops; + for (i = 0; i < btf_vlen(st_ops->type); i++) { + struct bpf_program *prog = st_ops->progs[i]; + void *kern_data; + int prog_fd; + + if (!prog) + continue; + + prog_fd = bpf_program__fd(prog); + kern_data = st_ops->kern_vdata + st_ops->kern_func_off[i]; + *(unsigned long *)kern_data = 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 = NULL; + for (i = 0; i < obj->nr_maps; i++) + if (bpf_map__is_struct_ops(&obj->maps[i])) + bpf_map_prepare_vdata(&obj->maps[i]); + obj->loaded = true; /* doesn't matter if successfully or not */ if (err) @@ -11566,22 +11591,34 @@ struct bpf_link *bpf_program__attach(const struct bpf_program *prog) return link; } +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 = 0; - if (bpf_map_delete_elem(link->fd, &zero)) - return -errno; + st_link = container_of(link, struct bpf_link_struct_ops, link); - 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; } 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 = 0; - int err; + struct bpf_link_struct_ops *link; + __u32 zero = 0; + int err, fd; if (!bpf_map__is_struct_ops(map) || map->fd == -1) return libbpf_err_ptr(-EINVAL); @@ -11590,31 +11627,34 @@ struct bpf_link *bpf_map__attach_struct_ops(const struct bpf_map *map) if (!link) return libbpf_err_ptr(-EINVAL); - st_ops = map->st_ops; - for (i = 0; i < btf_vlen(st_ops->type); i++) { - struct bpf_program *prog = st_ops->progs[i]; - void *kern_data; - int prog_fd; + /* kern_vdata should be prepared during the loading phase. */ + err = bpf_map_update_elem(map->fd, &zero, map->st_ops->kern_vdata, 0); + if (err) { + err = -errno; + free(link); + return libbpf_err_ptr(err); + } - if (!prog) - continue; - prog_fd = bpf_program__fd(prog); - kern_data = st_ops->kern_vdata + st_ops->kern_func_off[i]; - *(unsigned long *)kern_data = prog_fd; + if (!(map->def.map_flags & BPF_F_LINK)) { + /* Fake bpf_link */ + link->link.fd = map->fd; + link->map_fd = -1; + link->link.detach = bpf_link__detach_struct_ops; + return &link->link; } - err = bpf_map_update_elem(map->fd, &zero, st_ops->kern_vdata, 0); - if (err) { + fd = bpf_link_create(map->fd, -1, BPF_STRUCT_OPS, NULL); + if (fd < 0) { err = -errno; free(link); return libbpf_err_ptr(err); } - link->detach = bpf_link__detach_struct_ops; - link->fd = map->fd; + link->link.fd = fd; + link->map_fd = map->fd; - return link; + return &link->link; } typedef enum bpf_perf_event_ret (*bpf_perf_event_print_t)(struct perf_event_header *hdr,