From patchwork Thu Mar 16 02:36:37 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: 13176921 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 7CEACC6FD1D for ; Thu, 16 Mar 2023 02:37:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229513AbjCPCh6 (ORCPT ); Wed, 15 Mar 2023 22:37:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33374 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229542AbjCPCh5 (ORCPT ); Wed, 15 Mar 2023 22:37:57 -0400 Received: from mx0b-00082601.pphosted.com (mx0b-00082601.pphosted.com [67.231.153.30]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 044BACC304 for ; Wed, 15 Mar 2023 19:37:54 -0700 (PDT) Received: from pps.filterd (m0148460.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 32G1mbIl032505 for ; Wed, 15 Mar 2023 19:37:54 -0700 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=bLaBpB3ICw2koLk1Zlaoyy+AIJQaF6X/LxEMLl6f3bg=; b=XN98Qs59T4tHVgk5kUYFm38HtVV2pUTjPkqUaCqtWjJUworNj2MhJAJY5HpkgIHGv9I8 UK7Kpup6yTU2vgEfBTa48rB9VOlgzXmjBJnBxS9ZBsPSeqr1DzqebD0+Cpoi2vnLfKbX A3D/nEgA8ufAywQjJUWnmaHpDv8UULwnXNTGZzvcd1yQIRPGp1vEcR3teqIu/08mdsEZ 5YJYnC7tbBjbC3V7cVTGWREi9zzmN2yTRTntKDS/cKusGXnpSgodsNlfL2LlfmP9iyDO 0ZTERMLiWcgiYuaIGNEb6igtyejpVgvx/LEeSSQu/sE++TMlnwa6p9Uy6XmYyRF17crL sA== Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 3pbs38gbsc-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Wed, 15 Mar 2023 19:37:53 -0700 Received: from twshared33736.38.frc1.facebook.com (2620:10d:c085:108::4) by mail.thefacebook.com (2620:10d:c085:21d::4) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.17; Wed, 15 Mar 2023 19:37:52 -0700 Received: by devbig931.frc1.facebook.com (Postfix, from userid 460691) id 3433577002A4; Wed, 15 Mar 2023 19:37:43 -0700 (PDT) From: Kui-Feng Lee To: , , , , , , CC: Kui-Feng Lee Subject: [PATCH bpf-next v7 4/8] libbpf: Create a bpf_link in bpf_map__attach_struct_ops(). Date: Wed, 15 Mar 2023 19:36:37 -0700 Message-ID: <20230316023641.2092778-5-kuifeng@meta.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230316023641.2092778-1-kuifeng@meta.com> References: <20230316023641.2092778-1-kuifeng@meta.com> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-GUID: DmK7iRbgEE2V0iw-K5Z9VA_LIo_IZ3Yu X-Proofpoint-ORIG-GUID: DmK7iRbgEE2V0iw-K5Z9VA_LIo_IZ3Yu 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=2023-03-16_02,2023-03-15_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 | 90 +++++++++++++++++++++++++++++++----------- 1 file changed, 66 insertions(+), 24 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index a557718401e4..6dbae7ffab48 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 +7678,37 @@ 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_prepare_struct_ops(struct bpf_object *obj) +{ + int i; + + for (i = 0; i < obj->nr_maps; i++) + if (bpf_map__is_struct_ops(&obj->maps[i])) + bpf_map_prepare_vdata(&obj->maps[i]); + + return 0; +} + static int bpf_object_load(struct bpf_object *obj, int extra_log_level, const char *target_btf_path) { int err, i; @@ -7702,6 +7734,7 @@ static int bpf_object_load(struct bpf_object *obj, int extra_log_level, const ch err = err ? : bpf_object__relocate(obj, obj->btf_custom_path ? : target_btf_path); err = err ? : bpf_object__load_progs(obj, extra_log_level); err = err ? : bpf_object_init_prog_arrays(obj); + err = err ? : bpf_object_prepare_struct_ops(obj); if (obj->gen_loader) { /* reset FDs */ @@ -11566,22 +11599,30 @@ 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) + /* w/o a real link */ + return bpf_map_delete_elem(link->fd, &zero); + + return close(link->fd); } 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 +11631,32 @@ 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) { + free(link); + return libbpf_err_ptr(err); + } - if (!prog) - continue; + link->link.detach = bpf_link__detach_struct_ops; - 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)) { + /* w/o a real link */ + link->link.fd = map->fd; + link->map_fd = -1; + return &link->link; } - err = bpf_map_update_elem(map->fd, &zero, st_ops->kern_vdata, 0); - if (err) { - err = -errno; + fd = bpf_link_create(map->fd, -1, BPF_STRUCT_OPS, NULL); + if (fd < 0) { free(link); - return libbpf_err_ptr(err); + return libbpf_err_ptr(fd); } - 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,