From patchwork Thu Mar 16 02:36:39 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: 13176922 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 13783C6FD1D for ; Thu, 16 Mar 2023 02:38:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229778AbjCPCiE (ORCPT ); Wed, 15 Mar 2023 22:38:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33710 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229543AbjCPCiD (ORCPT ); Wed, 15 Mar 2023 22:38:03 -0400 Received: from mx0a-00082601.pphosted.com (mx0b-00082601.pphosted.com [67.231.153.30]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 28043ABADA for ; Wed, 15 Mar 2023 19:37:59 -0700 (PDT) Received: from pps.filterd (m0001303.ppops.net [127.0.0.1]) by m0001303.ppops.net (8.17.1.19/8.17.1.19) with ESMTP id 32G1makt009062 for ; Wed, 15 Mar 2023 19:37:58 -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=QycvHnbgwUnbcrYZODcnV5jg7n0J31oe6EYS4gId2cU=; b=jRabuAKKvG36C7gcqB1stizmVZw+lJMNVF3nAfSO1LxMIPO9BBFLYRo6uAbaM1G7E1SC Wnrv8OgVCN4przKzAqvUY0dp0Zl2kXKvtw3PkAy8+nliX7PJUScLsXpTK+aYMUS2KZUB buDtIeDUDmQFRzh2tIOjNIDEiPq9WR43oCc5s3/6ymcO1Toh8xeyDL44rwKYYBzstEG9 mbC1RUDWI9c0Uta4TASAIlOlr+Zfg14u6HZ3N7mNIEjW1JbSLipVk+EV25BgFfrhWQ0T iyWxCj/UszMvvLBaBsXLKT/R6FDx6duiyc+1lF5BbexLslE8a3vlz/5AV3T0FUNHDVNf Rw== Received: from maileast.thefacebook.com ([163.114.130.16]) by m0001303.ppops.net (PPS) with ESMTPS id 3pbs2d8cf6-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Wed, 15 Mar 2023 19:37:58 -0700 Received: from ash-exhub204.TheFacebook.com (2620:10d:c0a8:83::4) by ash-exhub202.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; Wed, 15 Mar 2023 19:37:53 -0700 Received: from twshared21709.17.frc2.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:83::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 19:37:53 -0700 Received: by devbig931.frc1.facebook.com (Postfix, from userid 460691) id 4480B77002C3; Wed, 15 Mar 2023 19:37:45 -0700 (PDT) From: Kui-Feng Lee To: , , , , , , CC: Kui-Feng Lee Subject: [PATCH bpf-next v7 6/8] libbpf: Update a bpf_link with another struct_ops. Date: Wed, 15 Mar 2023 19:36:39 -0700 Message-ID: <20230316023641.2092778-7-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: IeKRjnxdo4-1kqTw13xlEI8cdO4KTTFp X-Proofpoint-ORIG-GUID: IeKRjnxdo4-1kqTw13xlEI8cdO4KTTFp 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 Introduce bpf_link__update_map(), which allows to atomically update underlying struct_ops implementation for given struct_ops BPF link Signed-off-by: Kui-Feng Lee --- tools/lib/bpf/libbpf.c | 30 ++++++++++++++++++++++++++++++ tools/lib/bpf/libbpf.h | 1 + tools/lib/bpf/libbpf.map | 1 + 3 files changed, 32 insertions(+) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 6dbae7ffab48..63ec1f8fe8a0 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -11659,6 +11659,36 @@ struct bpf_link *bpf_map__attach_struct_ops(const struct bpf_map *map) return &link->link; } +/* + * 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 *map) +{ + struct bpf_link_struct_ops *st_ops_link; + __u32 zero = 0; + int err, fd; + + if (!bpf_map__is_struct_ops(map) || map->fd < 0) + return -EINVAL; + + st_ops_link = 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 = bpf_map_update_elem(map->fd, &zero, map->st_ops->kern_vdata, 0); + if (err && err != -EBUSY) + return err; + + fd = bpf_link_update(link->fd, map->fd, NULL); + if (fd < 0) + return fd; + + st_ops_link->map_fd = map->fd; + + return 0; +} + typedef enum bpf_perf_event_ret (*bpf_perf_event_print_t)(struct perf_event_header *hdr, void *private_data); 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; 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); 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;