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 AFA23C678D5 for ; Wed, 8 Mar 2023 00:53:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229760AbjCHAxm (ORCPT ); Tue, 7 Mar 2023 19:53:42 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57374 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229732AbjCHAxm (ORCPT ); Tue, 7 Mar 2023 19:53:42 -0500 Received: from mx0a-00082601.pphosted.com (mx0a-00082601.pphosted.com [67.231.145.42]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2C9BB99245 for ; Tue, 7 Mar 2023 16:53:41 -0800 (PST) Received: from pps.filterd (m0044012.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 32803UuC006025 for ; Tue, 7 Mar 2023 16:53:40 -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=xGyFyd+lQUC+ifSexXOhvgCJY1riQKqULnjP5jvfkeY=; b=cSSiHGpn2hClql9nz4tm7lfs82Kd8xgCZrRnHepK6LJnAQlFV5bIgFMSCOl4aVYpi0Fg xvTj4xG4KXzjTqNblzMQNu0qsaFiq2IAZTIQycRP2F9KGeEekNLdeb/9CyqJJUuZZuw7 h4LrCXNfuF5523xJRbymiokQct8GrrcztmYYUIIx65L6R+x6x2dcsagVZiKJFiAQo8Ha KSiKU4K9tVN/iqxJ6XS30s3KkNMq5EdvjKL4KGUKVVIquQAB93iChcFshqSRWReSi5/c r8oRAvKCsAKe/LSoU0MN0NUlWgAE42s/VdeK+2kYIpwidLX63FCxuTqBVsZ2VIgWAGDl 2w== Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 3p6fft87v5-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Tue, 07 Mar 2023 16:53:40 -0800 Received: from twshared24004.14.frc2.facebook.com (2620:10d:c085:208::f) 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; Tue, 7 Mar 2023 16:53:39 -0800 Received: by devbig931.frc1.facebook.com (Postfix, from userid 460691) id A6C6C6C92E1E; Tue, 7 Mar 2023 16:50:54 -0800 (PST) From: Kui-Feng Lee To: , , , , , , CC: Kui-Feng Lee Subject: [PATCH bpf-next v5 6/8] libbpf: Update a bpf_link with another struct_ops. Date: Tue, 7 Mar 2023 16:50:48 -0800 Message-ID: <20230308005050.255859-7-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 Content-Transfer-Encoding: quoted-printable X-FB-Internal: Safe Content-Type: text/plain X-Proofpoint-GUID: ckTmwa2L7ajxZy-SmLOEpTugHT2I4JNA X-Proofpoint-ORIG-GUID: ckTmwa2L7ajxZy-SmLOEpTugHT2I4JNA 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 Introduce bpf_link__update_struct_ops(), which will allow you to effortlessly transition the struct_ops map of any given bpf_link into an alternative. Signed-off-by: Kui-Feng Lee --- tools/lib/bpf/libbpf.c | 36 ++++++++++++++++++++++++++++++++++++ tools/lib/bpf/libbpf.h | 1 + tools/lib/bpf/libbpf.map | 1 + 3 files changed, 38 insertions(+) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index f70b55c0f40e..0406d0e00e1f 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -11657,6 +11657,42 @@ struct bpf_link *bpf_map__attach_struct_ops(cons= t struct bpf_map *map) return &link->link; } =20 +/* + * Swap the back struct_ops of a link with a new struct_ops map. + */ +int bpf_link__update_map(struct bpf_link *link, const struct bpf_map *ma= p) +{ + struct bpf_link_struct_ops *st_ops_link; + __u32 zero =3D 0; + int err, fd; + + if (!bpf_map__is_struct_ops(map) || map->fd =3D=3D -1) + return -EINVAL; + + st_ops_link =3D container_of(link, struct bpf_link_struct_ops, link); + /* Ensure the type of a link is correct */ + if (st_ops_link->map_fd < 0) + return -EINVAL; + + err =3D bpf_map_update_elem(map->fd, &zero, map->st_ops->kern_vdata, 0)= ; + if (err && errno !=3D EBUSY) { + err =3D -errno; + free(link); + return err; + } + + fd =3D bpf_link_update(link->fd, map->fd, NULL); + if (fd < 0) { + err =3D -errno; + free(link); + return err; + } + + st_ops_link->map_fd =3D map->fd; + + return 0; +} + typedef enum bpf_perf_event_ret (*bpf_perf_event_print_t)(struct perf_ev= ent_header *hdr, void *private_data); =20 diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index db4992a036f8..1615e55e2e79 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -719,6 +719,7 @@ bpf_program__attach_freplace(const struct bpf_program= *prog, struct bpf_map; =20 LIBBPF_API struct bpf_link *bpf_map__attach_struct_ops(const struct bpf_= map *map); +LIBBPF_API int bpf_link__update_map(struct bpf_link *link, const struct = bpf_map *map); =20 struct bpf_iter_attach_opts { size_t sz; /* size of this struct for forward/backward compatibility */ diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 50dde1f6521e..cc05be376257 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -387,6 +387,7 @@ LIBBPF_1.2.0 { global: bpf_btf_get_info_by_fd; bpf_link_get_info_by_fd; + bpf_link__update_map; bpf_map_get_info_by_fd; bpf_prog_get_info_by_fd; } LIBBPF_1.1.0; --=20 2.34.1