From patchwork Mon Sep 25 10:55:49 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chuyi Zhou X-Patchwork-Id: 13397645 X-Patchwork-Delegate: bpf@iogearbox.net Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C72EA168C9 for ; Mon, 25 Sep 2023 10:56:13 +0000 (UTC) Received: from mail-pg1-x529.google.com (mail-pg1-x529.google.com [IPv6:2607:f8b0:4864:20::529]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9FF97BE for ; Mon, 25 Sep 2023 03:56:12 -0700 (PDT) Received: by mail-pg1-x529.google.com with SMTP id 41be03b00d2f7-578d791dd91so4501411a12.0 for ; Mon, 25 Sep 2023 03:56:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1695639372; x=1696244172; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=hrdiacOpaESaqEXHiOrMTWSWkSGBNArwX1oK/BX79n4=; b=KRTF0ghbHQmLgnAF6+iQYPHAJa2puc+eAnjl1P4XiCfqDpVjoE0ci+7On5ehlDFPIw R6xnvs9V6NwgXhxUGV7G4OH5JOm+tlIn/cLGibVJw51zLJgOsNpP26XzY4TP6I1e6DgK uk28NftmHFNXunvxqUsTKRJvPh2YRdKcRm22RkbwpJ7neifTE6ldJyki/89hwlxk7Wi9 ibVyURD5xoGxUTCvKts2rUxG5L9gT42YtRl+zj9WtqR8XkpBjdKrH47s72i18eBJgdO8 iy5gcZq3HAXoWz3S2E79SEK7Pcc/v+w7xZCsqZd31AbI0S5oGu92eH9Xr0yfdNPUTqSj foug== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1695639372; x=1696244172; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=hrdiacOpaESaqEXHiOrMTWSWkSGBNArwX1oK/BX79n4=; b=MCT9HdXXsHLIKLaSTI8PDYEqN2jCVOsdTPYtdSi0AMCE6xNmQKJLT8Y5s6+j8oiqiM 5TYD7IijHkirK08ZqoouV9KsezH3HT2iI4FMh/Afy/KFLWimc7lYQW1wJkxuNR/iSxuH J7oDPk8yV+MLHUAJ3/WZ+6o7AWT4lHaFrK4JqQIOrvPFMhrtHgj+y1megP8Nodrfwdhz pyBFRbVoiikiSnYtccvZEj2wwSmtp9CfiWqHlG/uAnxOfMK8fE57PQom/V8Wquk45bXC HUUDlr2YqLMgdtknGpGQn704Dn3TpAnvUaxOT6bPIJJx6IJhQVF4SJcegXFRlHdJ7ege 78yg== X-Gm-Message-State: AOJu0Ywz91y91t4ncdd0wlF68S5dObScvyevM/huARKsd5A50iSz6mFr ZxDM8vJt0gFKafR1M1H+jjUbiIISWZooMNXy0tk= X-Google-Smtp-Source: AGHT+IH8Hsd65TRqjkZsDY7MW0VbsIM7FfKFrnxYWvPwtJ03hxT/bkpnb9jd5tLVrjAtCo6fCsdcgg== X-Received: by 2002:a17:90b:e07:b0:268:798:a28b with SMTP id ge7-20020a17090b0e0700b002680798a28bmr14579618pjb.23.1695639371959; Mon, 25 Sep 2023 03:56:11 -0700 (PDT) Received: from n37-019-243.byted.org ([180.184.51.134]) by smtp.gmail.com with ESMTPSA id y9-20020a17090a16c900b002772faee740sm2297842pje.5.2023.09.25.03.56.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 25 Sep 2023 03:56:11 -0700 (PDT) From: Chuyi Zhou To: bpf@vger.kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@kernel.org, tj@kernel.org, linux-kernel@vger.kernel.org, Chuyi Zhou Subject: [PATCH bpf-next v3 4/7] bpf: Introduce css open-coded iterator kfuncs Date: Mon, 25 Sep 2023 18:55:49 +0800 Message-Id: <20230925105552.817513-5-zhouchuyi@bytedance.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20230925105552.817513-1-zhouchuyi@bytedance.com> References: <20230925105552.817513-1-zhouchuyi@bytedance.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_BLOCKED, SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: bpf@iogearbox.net This Patch adds kfuncs bpf_iter_css_{new,next,destroy} which allow creation and manipulation of struct bpf_iter_css in open-coded iterator style. These kfuncs actually wrapps css_next_descendant_{pre, post}. css_iter can be used to: 1) iterating a sepcific cgroup tree with pre/post/up order 2) iterating cgroup_subsystem in BPF Prog, like for_each_mem_cgroup_tree/cpuset_for_each_descendant_pre in kernel. The API design is consistent with cgroup_iter. bpf_iter_css_new accepts parameters defining iteration order and starting css. Here we also reuse BPF_CGROUP_ITER_DESCENDANTS_PRE, BPF_CGROUP_ITER_DESCENDANTS_POST, BPF_CGROUP_ITER_ANCESTORS_UP enums. Signed-off-by: Chuyi Zhou --- kernel/bpf/cgroup_iter.c | 57 +++++++++++++++++++ kernel/bpf/helpers.c | 3 + .../testing/selftests/bpf/bpf_experimental.h | 6 ++ 3 files changed, 66 insertions(+) diff --git a/kernel/bpf/cgroup_iter.c b/kernel/bpf/cgroup_iter.c index 810378f04fbc..ebc3d9471f52 100644 --- a/kernel/bpf/cgroup_iter.c +++ b/kernel/bpf/cgroup_iter.c @@ -294,3 +294,60 @@ static int __init bpf_cgroup_iter_init(void) } late_initcall(bpf_cgroup_iter_init); + +struct bpf_iter_css { + __u64 __opaque[2]; + __u32 __opaque_int[1]; +} __attribute__((aligned(8))); + +struct bpf_iter_css_kern { + struct cgroup_subsys_state *start; + struct cgroup_subsys_state *pos; + int order; +} __attribute__((aligned(8))); + +__bpf_kfunc int bpf_iter_css_new(struct bpf_iter_css *it, + struct cgroup_subsys_state *start, enum bpf_cgroup_iter_order order) +{ + struct bpf_iter_css_kern *kit = (void *)it; + kit->start = NULL; + BUILD_BUG_ON(sizeof(struct bpf_iter_css_kern) != sizeof(struct bpf_iter_css)); + BUILD_BUG_ON(__alignof__(struct bpf_iter_css_kern) != __alignof__(struct bpf_iter_css)); + switch (order) { + case BPF_CGROUP_ITER_DESCENDANTS_PRE: + case BPF_CGROUP_ITER_DESCENDANTS_POST: + case BPF_CGROUP_ITER_ANCESTORS_UP: + break; + default: + return -EINVAL; + } + + kit->start = start; + kit->pos = NULL; + kit->order = order; + return 0; +} + +__bpf_kfunc struct cgroup_subsys_state *bpf_iter_css_next(struct bpf_iter_css *it) +{ + struct bpf_iter_css_kern *kit = (void *)it; + if (!kit->start) + return NULL; + + switch (kit->order) { + case BPF_CGROUP_ITER_DESCENDANTS_PRE: + kit->pos = css_next_descendant_pre(kit->pos, kit->start); + break; + case BPF_CGROUP_ITER_DESCENDANTS_POST: + kit->pos = css_next_descendant_post(kit->pos, kit->start); + break; + default: + kit->pos = kit->pos ? kit->pos->parent : kit->start; + } + + return kit->pos; +} + +__bpf_kfunc void bpf_iter_css_destroy(struct bpf_iter_css *it) +{ +} diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 556262c27a75..9c3af36249a2 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -2510,6 +2510,9 @@ BTF_ID_FLAGS(func, bpf_iter_css_task_destroy, KF_ITER_DESTROY) BTF_ID_FLAGS(func, bpf_iter_task_new, KF_ITER_NEW | KF_TRUSTED_ARGS) BTF_ID_FLAGS(func, bpf_iter_task_next, KF_ITER_NEXT | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_iter_task_destroy, KF_ITER_DESTROY) +BTF_ID_FLAGS(func, bpf_iter_css_new, KF_ITER_NEW | KF_TRUSTED_ARGS) +BTF_ID_FLAGS(func, bpf_iter_css_next, KF_ITER_NEXT | KF_RET_NULL) +BTF_ID_FLAGS(func, bpf_iter_css_destroy, KF_ITER_DESTROY) BTF_ID_FLAGS(func, bpf_dynptr_adjust) BTF_ID_FLAGS(func, bpf_dynptr_is_null) BTF_ID_FLAGS(func, bpf_dynptr_is_rdonly) diff --git a/tools/testing/selftests/bpf/bpf_experimental.h b/tools/testing/selftests/bpf/bpf_experimental.h index d989775dbdb5..aa247d1d81d1 100644 --- a/tools/testing/selftests/bpf/bpf_experimental.h +++ b/tools/testing/selftests/bpf/bpf_experimental.h @@ -174,4 +174,10 @@ extern int bpf_iter_task_new(struct bpf_iter_task *it, struct task_struct *task, extern struct task_struct *bpf_iter_task_next(struct bpf_iter_task *it) __weak __ksym; extern void bpf_iter_task_destroy(struct bpf_iter_task *it) __weak __ksym; +struct bpf_iter_css; +extern int bpf_iter_css_new(struct bpf_iter_css *it, + struct cgroup_subsys_state *start, enum bpf_cgroup_iter_order order) __weak __ksym; +extern struct cgroup_subsys_state *bpf_iter_css_next(struct bpf_iter_css *it) __weak __ksym; +extern void bpf_iter_css_destroy(struct bpf_iter_css *it) __weak __ksym; + #endif