From nobody Fri Jan 2 00:56:56 2026 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 5128BCDB483 for ; Wed, 18 Oct 2023 06:04:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344457AbjJRGEA (ORCPT ); Wed, 18 Oct 2023 02:04:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41256 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344419AbjJRGD6 (ORCPT ); Wed, 18 Oct 2023 02:03:58 -0400 Received: from mail-pg1-x52e.google.com (mail-pg1-x52e.google.com [IPv6:2607:f8b0:4864:20::52e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AF755F7 for ; Tue, 17 Oct 2023 23:03:34 -0700 (PDT) Received: by mail-pg1-x52e.google.com with SMTP id 41be03b00d2f7-5a9bf4fbd3fso3906115a12.1 for ; Tue, 17 Oct 2023 23:03:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1697609014; x=1698213814; 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=FNW2oYGtelVvgczyk2A13Ij/ocoUNYFTCyV6b+P6gh8=; b=bAuwMM04S+xXGF2mph5y8RlqZdBfuL+ajSBfC8QXGjoeoJLWhuDh9nA+BdUrXXdLWW rAcCpcs/Es1uO8VE3XLTgYaTkbQjVIEV9jUb7FbiWZw7IQFuWX4KPZshS/VpkfuxGY95 gG+7EPKiLPEgzcEEtBy0H+VoRbAHW+VPthYHyGF2s1f0FyHjGshSkGdg98/x2qOIMNX3 KzKzI0rP+BpU16oX2RhLPKA7HZ8oP3OY22w/9SvTGbbI+UBlJ4soHBifGHe1CQu6RrRg R3vJ9t8sdS0Zt4Wy4xat/oxRzcwuGr+5ANeSo+Tbq7RprU/9rGDHYL09ypIrKBbbatUI jiog== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1697609014; x=1698213814; 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=FNW2oYGtelVvgczyk2A13Ij/ocoUNYFTCyV6b+P6gh8=; b=BA3k0JmRTqUOp0ziil2uuPLvvmTj4Z1IZUEwlrPJ69PZCCHf16wxQsTtgTTzJtqFrp V5qy9cojHMickWNrwkITHliZD1C7yxHqCuztqU5/IzMgsw7SG9sXLLtnYa9GTfW8Z39x DqsNhl24phCvDqhs+onzvF0XSEmt1DIiRGeD9zkdkAboms1f3P1apzqJMDXIIrjuAIQM jqAzKTjI7EV6ZIGse3S/Le/jn/JmbJD5wfKpWevdGqHy6S+GJpagBpyT88rqK8prVrJd 9n3LjvZXHH62GZ8i+bpqMiURaDpMx2Qli1NP9Qj7QwtGvNHdKXrzIR2HfpiY5hY8js7U EAFw== X-Gm-Message-State: AOJu0Yx/csEb4W/7uRZkVOXTRxIbXW9vCybDwnmesCeMYWpDd6aBKwfj wQCh0yGhp3ONd8z68B6yEzD1UQ+LTpUEkT4msEc= X-Google-Smtp-Source: AGHT+IHqopjsr9BP1ss3CSoo05FNLUC7HlYkBIJAwdcXGipKNcB3IBn5N91CU3D2e0oxtKbS3nDKUA== X-Received: by 2002:a05:6a20:72ab:b0:15e:bb88:b76e with SMTP id o43-20020a056a2072ab00b0015ebb88b76emr4544752pzk.14.1697609014178; Tue, 17 Oct 2023 23:03:34 -0700 (PDT) Received: from n37-019-243.byted.org ([180.184.51.40]) by smtp.gmail.com with ESMTPSA id b14-20020a17090acc0e00b00276cb03a0e9sm505782pju.46.2023.10.17.23.03.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 17 Oct 2023 23:03:33 -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 v6 1/8] cgroup: Prepare for using css_task_iter_*() in BPF Date: Wed, 18 Oct 2023 14:03:11 +0800 Message-Id: <20231018060318.105524-2-zhouchuyi@bytedance.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20231018060318.105524-1-zhouchuyi@bytedance.com> References: <20231018060318.105524-1-zhouchuyi@bytedance.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" This patch makes some preparations for using css_task_iter_*() in BPF Program. 1. Flags CSS_TASK_ITER_* are #define-s and it's not easy for bpf prog to use them. Convert them to enum so bpf prog can take them from vmlinux.h. 2. In the next patch we will add css_task_iter_*() in common kfuncs which is not safe. Since css_task_iter_*() does spin_unlock_irq() which might screw up irq flags depending on the context where bpf prog is running. So we should use irqsave/irqrestore here and the switching is harmless. Suggested-by: Alexei Starovoitov Signed-off-by: Chuyi Zhou Acked-by: Tejun Heo --- include/linux/cgroup.h | 12 +++++------- kernel/cgroup/cgroup.c | 18 ++++++++++++------ 2 files changed, 17 insertions(+), 13 deletions(-) diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index b307013b9c6c..0ef0af66080e 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -40,13 +40,11 @@ struct kernel_clone_args; #define CGROUP_WEIGHT_DFL 100 #define CGROUP_WEIGHT_MAX 10000 =20 -/* walk only threadgroup leaders */ -#define CSS_TASK_ITER_PROCS (1U << 0) -/* walk all threaded css_sets in the domain */ -#define CSS_TASK_ITER_THREADED (1U << 1) - -/* internal flags */ -#define CSS_TASK_ITER_SKIPPED (1U << 16) +enum { + CSS_TASK_ITER_PROCS =3D (1U << 0), /* walk only threadgroup leaders */ + CSS_TASK_ITER_THREADED =3D (1U << 1), /* walk all threaded css_sets in t= he domain */ + CSS_TASK_ITER_SKIPPED =3D (1U << 16), /* internal flags */ +}; =20 /* a css_task_iter should be treated as an opaque object */ struct css_task_iter { diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 1fb7f562289d..b6d64f3b8888 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -4917,9 +4917,11 @@ static void css_task_iter_advance(struct css_task_it= er *it) void css_task_iter_start(struct cgroup_subsys_state *css, unsigned int fla= gs, struct css_task_iter *it) { + unsigned long irqflags; + memset(it, 0, sizeof(*it)); =20 - spin_lock_irq(&css_set_lock); + spin_lock_irqsave(&css_set_lock, irqflags); =20 it->ss =3D css->ss; it->flags =3D flags; @@ -4933,7 +4935,7 @@ void css_task_iter_start(struct cgroup_subsys_state *= css, unsigned int flags, =20 css_task_iter_advance(it); =20 - spin_unlock_irq(&css_set_lock); + spin_unlock_irqrestore(&css_set_lock, irqflags); } =20 /** @@ -4946,12 +4948,14 @@ void css_task_iter_start(struct cgroup_subsys_state= *css, unsigned int flags, */ struct task_struct *css_task_iter_next(struct css_task_iter *it) { + unsigned long irqflags; + if (it->cur_task) { put_task_struct(it->cur_task); it->cur_task =3D NULL; } =20 - spin_lock_irq(&css_set_lock); + spin_lock_irqsave(&css_set_lock, irqflags); =20 /* @it may be half-advanced by skips, finish advancing */ if (it->flags & CSS_TASK_ITER_SKIPPED) @@ -4964,7 +4968,7 @@ struct task_struct *css_task_iter_next(struct css_tas= k_iter *it) css_task_iter_advance(it); } =20 - spin_unlock_irq(&css_set_lock); + spin_unlock_irqrestore(&css_set_lock, irqflags); =20 return it->cur_task; } @@ -4977,11 +4981,13 @@ struct task_struct *css_task_iter_next(struct css_t= ask_iter *it) */ void css_task_iter_end(struct css_task_iter *it) { + unsigned long irqflags; + if (it->cur_cset) { - spin_lock_irq(&css_set_lock); + spin_lock_irqsave(&css_set_lock, irqflags); list_del(&it->iters_node); put_css_set_locked(it->cur_cset); - spin_unlock_irq(&css_set_lock); + spin_unlock_irqrestore(&css_set_lock, irqflags); } =20 if (it->cur_dcset) --=20 2.20.1