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 X-Spam-Level: X-Spam-Status: No, score=-9.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C4828C54E49 for ; Sat, 9 May 2020 17:59:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A6461208CA for ; Sat, 9 May 2020 17:59:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="gdr8HISn" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728838AbgEIR7w (ORCPT ); Sat, 9 May 2020 13:59:52 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:27030 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728564AbgEIR7N (ORCPT ); Sat, 9 May 2020 13:59:13 -0400 Received: from pps.filterd (m0109333.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 049HuSmJ026231 for ; Sat, 9 May 2020 10:59:12 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : content-type; s=facebook; bh=TJFXJiiakuJUVspAT6aTlAB5fFSLYAO/nM1aUaHyJLs=; b=gdr8HISnm7KT2+gkpAZbUzKsymRF/8vsn/VMZ7ICe1Q+jxquqcS9qzAeOZyBjd3FBYUB xUx/nmSg/qBuCBgCSzBdi+qiwGRIBo71f/NVYxkYgKfrth7J/I9bPiXx/bJ3yU9glbNA w29m3uQUjCS0oy/mj6sNoTOO87/gl/H5Au0= Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 30wsbq1hb3-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Sat, 09 May 2020 10:59:12 -0700 Received: from intmgw001.08.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 15.1.1847.3; Sat, 9 May 2020 10:59:11 -0700 Received: by devbig003.ftw2.facebook.com (Postfix, from userid 128203) id E8BDC37008E2; Sat, 9 May 2020 10:59:07 -0700 (PDT) Smtp-Origin-Hostprefix: devbig From: Yonghong Song Smtp-Origin-Hostname: devbig003.ftw2.facebook.com To: Andrii Nakryiko , , Martin KaFai Lau , CC: Alexei Starovoitov , Daniel Borkmann , Smtp-Origin-Cluster: ftw2c04 Subject: [PATCH bpf-next v4 08/21] bpf: implement common macros/helpers for target iterators Date: Sat, 9 May 2020 10:59:07 -0700 Message-ID: <20200509175907.2475956-1-yhs@fb.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200509175859.2474608-1-yhs@fb.com> References: <20200509175859.2474608-1-yhs@fb.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-FB-Internal: Safe Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.216,18.0.676 definitions=2020-05-09_06:2020-05-08,2020-05-09 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 malwarescore=0 lowpriorityscore=0 suspectscore=0 adultscore=0 spamscore=0 bulkscore=0 phishscore=0 clxscore=1015 mlxscore=0 priorityscore=1501 impostorscore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2005090155 X-FB-Internal: deliver Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Macro DEFINE_BPF_ITER_FUNC is implemented so target can define an init function to capture the BTF type which represents the target. The bpf_iter_meta is a structure holding meta data, common to all targets in the bpf program. Additional marker functions are called before or after bpf_seq_read() show()/next()/stop() callback functions to help calculate precise seq_num and whether call bpf_prog inside stop(). Two functions, bpf_iter_get_info() and bpf_iter_run_prog(), are implemented so target can get needed information from bpf_iter infrastructure and can run the program. Acked-by: Andrii Nakryiko Signed-off-by: Yonghong Song --- include/linux/bpf.h | 11 ++++++ kernel/bpf/bpf_iter.c | 85 ++++++++++++++++++++++++++++++++++++++++--- 2 files changed, 91 insertions(+), 5 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index b06653ab3476..ffe0b9b669bf 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1129,6 +1129,9 @@ int bpf_obj_pin_user(u32 ufd, const char __user *pa= thname); int bpf_obj_get_user(const char __user *pathname, int flags); =20 #define BPF_ITER_FUNC_PREFIX "__bpf_iter__" +#define DEFINE_BPF_ITER_FUNC(target, args...) \ + extern int __bpf_iter__ ## target(args); \ + int __init __bpf_iter__ ## target(args) { return 0; } =20 typedef int (*bpf_iter_init_seq_priv_t)(void *private_data); typedef void (*bpf_iter_fini_seq_priv_t)(void *private_data); @@ -1141,12 +1144,20 @@ struct bpf_iter_reg { u32 seq_priv_size; }; =20 +struct bpf_iter_meta { + __bpf_md_ptr(struct seq_file *, seq); + u64 session_id; + u64 seq_num; +}; + int bpf_iter_reg_target(struct bpf_iter_reg *reg_info); void bpf_iter_unreg_target(const char *target); bool bpf_iter_prog_supported(struct bpf_prog *prog); int bpf_iter_link_attach(const union bpf_attr *attr, struct bpf_prog *pr= og); int bpf_iter_new_fd(struct bpf_link *link); bool bpf_link_is_iter(struct bpf_link *link); +struct bpf_prog *bpf_iter_get_info(struct bpf_iter_meta *meta, bool in_s= top); +int bpf_iter_run_prog(struct bpf_prog *prog, void *ctx); =20 int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value); int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value); diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c index 090f09b0eacb..30efd15cd4a0 100644 --- a/kernel/bpf/bpf_iter.c +++ b/kernel/bpf/bpf_iter.c @@ -41,6 +41,33 @@ static atomic64_t session_id; =20 static int prepare_seq_file(struct file *file, struct bpf_iter_link *lin= k); =20 +static void bpf_iter_inc_seq_num(struct seq_file *seq) +{ + struct bpf_iter_priv_data *iter_priv; + + iter_priv =3D container_of(seq->private, struct bpf_iter_priv_data, + target_private); + iter_priv->seq_num++; +} + +static void bpf_iter_dec_seq_num(struct seq_file *seq) +{ + struct bpf_iter_priv_data *iter_priv; + + iter_priv =3D container_of(seq->private, struct bpf_iter_priv_data, + target_private); + iter_priv->seq_num--; +} + +static void bpf_iter_done_stop(struct seq_file *seq) +{ + struct bpf_iter_priv_data *iter_priv; + + iter_priv =3D container_of(seq->private, struct bpf_iter_priv_data, + target_private); + iter_priv->done_stop =3D true; +} + /* bpf_seq_read, a customized and simpler version for bpf iterator. * no_llseek is assumed for this file. * The following are differences from seq_read(): @@ -93,6 +120,10 @@ static ssize_t bpf_seq_read(struct file *file, char _= _user *buf, size_t size, =20 err =3D seq->op->show(seq, p); if (err > 0) { + /* object is skipped, decrease seq_num, so next + * valid object can reuse the same seq_num. + */ + bpf_iter_dec_seq_num(seq); seq->count =3D 0; } else if (err < 0 || seq_has_overflowed(seq)) { if (!err) @@ -117,11 +148,15 @@ static ssize_t bpf_seq_read(struct file *file, char= __user *buf, size_t size, if (IS_ERR_OR_NULL(p)) break; =20 + /* got a valid next object, increase seq_num */ + bpf_iter_inc_seq_num(seq); + if (seq->count >=3D size) break; =20 err =3D seq->op->show(seq, p); if (err > 0) { + bpf_iter_dec_seq_num(seq); seq->count =3D offs; } else if (err < 0 || seq_has_overflowed(seq)) { seq->count =3D offs; @@ -138,11 +173,15 @@ static ssize_t bpf_seq_read(struct file *file, char= __user *buf, size_t size, offs =3D seq->count; /* bpf program called if !p */ seq->op->stop(seq, p); - if (!p && seq_has_overflowed(seq)) { - seq->count =3D offs; - if (offs =3D=3D 0) { - err =3D -E2BIG; - goto done; + if (!p) { + if (!seq_has_overflowed(seq)) { + bpf_iter_done_stop(seq); + } else { + seq->count =3D offs; + if (offs =3D=3D 0) { + err =3D -E2BIG; + goto done; + } } } =20 @@ -453,3 +492,39 @@ int bpf_iter_new_fd(struct bpf_link *link) put_unused_fd(fd); return err; } + +struct bpf_prog *bpf_iter_get_info(struct bpf_iter_meta *meta, bool in_s= top) +{ + struct bpf_iter_priv_data *iter_priv; + struct seq_file *seq; + void *seq_priv; + + seq =3D meta->seq; + if (seq->file->f_op !=3D &bpf_iter_fops) + return NULL; + + seq_priv =3D seq->private; + iter_priv =3D container_of(seq_priv, struct bpf_iter_priv_data, + target_private); + + if (in_stop && iter_priv->done_stop) + return NULL; + + meta->session_id =3D iter_priv->session_id; + meta->seq_num =3D iter_priv->seq_num; + + return iter_priv->prog; +} + +int bpf_iter_run_prog(struct bpf_prog *prog, void *ctx) +{ + int ret; + + rcu_read_lock(); + migrate_disable(); + ret =3D BPF_PROG_RUN(prog, ctx); + migrate_enable(); + rcu_read_unlock(); + + return ret =3D=3D 0 ? 0 : -EAGAIN; +} --=20 2.24.1