From patchwork Thu Feb 23 01:12:35 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: 13149751 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 8BE3CC636D6 for ; Thu, 23 Feb 2023 01:12:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231820AbjBWBMx (ORCPT ); Wed, 22 Feb 2023 20:12:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53612 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232785AbjBWBMw (ORCPT ); Wed, 22 Feb 2023 20:12:52 -0500 Received: from mx0a-00082601.pphosted.com (mx0b-00082601.pphosted.com [67.231.153.30]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F20902D59 for ; Wed, 22 Feb 2023 17:12:49 -0800 (PST) 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 31MNBsPi019909 for ; Wed, 22 Feb 2023 17:12:49 -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=voRTy+0tce4KtlN7cCQNP3rHX9Y4fzbG9XrBeQXs0ek=; b=QwmNdkbtvY/DJV+e18eeJFaMp9Nc3KfM7Qh8uzKocAxPCmD0Ha/j+suxqa7tLJmIHuuv RKkrcL7MA6Elt754ldN1zLBcVuW3QFonwzOHaQEKMuGdWkKyvBc9P+oLmQ51/1rA1e7s Wte3yrzzaTz5EydpF5rPCpq5btHVeDBYACk/np2XApmAB3DgQmoIiUAMDOxt3bphZlAM +0JqK8djOqg7vLIlr7Nlu+doKXOCqzDh5+xYq9L+N4i9d1Nc3yyLEw915Biac6Jadf5r RHpT+55MMIlMoX7xyroaUbjRCpzjvD51W9hHIWJmo/1tj6bLMAnC2leb4Kiz771I7TkL 3A== Received: from maileast.thefacebook.com ([163.114.130.16]) by m0001303.ppops.net (PPS) with ESMTPS id 3nw5n4sd5n-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Wed, 22 Feb 2023 17:12:48 -0800 Received: from twshared52565.14.frc2.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:83::7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.17; Wed, 22 Feb 2023 17:12:48 -0800 Received: by devbig931.frc1.facebook.com (Postfix, from userid 460691) id 6A0275BD8CFA; Wed, 22 Feb 2023 17:12:41 -0800 (PST) From: Kui-Feng Lee To: , , , , , , CC: Kui-Feng Lee Subject: [PATCH bpf-next v2 3/6] libbpf: Create a bpf_link in bpf_map__attach_struct_ops(). Date: Wed, 22 Feb 2023 17:12:35 -0800 Message-ID: <20230223011238.12313-4-kuifeng@meta.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20230223011238.12313-1-kuifeng@meta.com> References: <20230223011238.12313-1-kuifeng@meta.com> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-ORIG-GUID: iaCQdnCJVSQMA4g37SCEh5b9h1nGM7XX X-Proofpoint-GUID: iaCQdnCJVSQMA4g37SCEh5b9h1nGM7XX X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.219,Aquarius:18.0.930,Hydra:6.0.562,FMLib:17.11.170.22 definitions=2023-02-22_12,2023-02-22_02,2023-02-09_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/bpf.c | 2 + tools/lib/bpf/libbpf.c | 84 ++++++++++++++++++++++++++++++++---------- 2 files changed, 66 insertions(+), 20 deletions(-) diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index 9aff98f42a3d..6e270bb95ab7 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -731,6 +731,8 @@ int bpf_link_create(int prog_fd, int target_fd, if (!OPTS_ZEROED(opts, tracing)) return libbpf_err(-EINVAL); break; + case BPF_STRUCT_OPS: + break; default: if (!OPTS_ZEROED(opts, flags)) return libbpf_err(-EINVAL); diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 35a698eb825d..40f239cd1150 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -115,6 +115,7 @@ 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) @@ -11429,11 +11454,29 @@ 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)) + st_link = container_of(link, struct bpf_link_struct_ops, link); + + if (st_link->map_fd < 0) { + /* Fake bpf_link */ + if (bpf_map_delete_elem(link->fd, &zero)) + return -errno; + return 0; + } + + if (bpf_map_delete_elem(st_link->map_fd, &zero)) + return -errno; + + if (close(link->fd)) return -errno; return 0; @@ -11441,10 +11484,9 @@ static int bpf_link__detach_struct_ops(struct bpf_link *link) 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); @@ -11453,31 +11495,33 @@ 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; + 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; + 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)) { + /* Fake bpf_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) { + 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,