From nobody Sat Jan 3 00:17:40 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 2576DE95A63 for ; Sat, 7 Oct 2023 12:45:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343958AbjJGMpj (ORCPT ); Sat, 7 Oct 2023 08:45:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36344 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343919AbjJGMph (ORCPT ); Sat, 7 Oct 2023 08:45:37 -0400 Received: from mail-oo1-xc34.google.com (mail-oo1-xc34.google.com [IPv6:2607:f8b0:4864:20::c34]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F02B3BC for ; Sat, 7 Oct 2023 05:45:35 -0700 (PDT) Received: by mail-oo1-xc34.google.com with SMTP id 006d021491bc7-57bb6b1f764so1861739eaf.2 for ; Sat, 07 Oct 2023 05:45:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1696682735; x=1697287535; 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=GXB8f0YpomSByhTROPCJvlR5F8Dh/zJXh+SUbpi5T9ze2hLQp3UwUozDQZWnEXGR+w 6O5VvXtLu+qdM2AWRLPbYpIlC2Pi+4miUmgAdiiKJ8sIG00GAYpWqh2RckHNY2tuF5e2 zofEEBau0bTtfLAsSsjuSHlc7FPlUgtdCZ6RXX+6V56WA7He9xHBV9jC59dkDPO9fBdW 1EFjmnVjM36kSn9B1mmjaqMSpYJmx1jIf7naNggIrKKxQ2ifnlWjs8A1c0AaJqHLTMmv +HdbpmM3eamJLNmA41nQW4Vaihnwr9RtRyTGUs2lgf02/RVU/bIWiuLh7LmxK9lrTecY QI8A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1696682735; x=1697287535; 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=wLzX4BT4LWUpnWQWM/rXTmm3oZAa0O5mI2QYjGoBcwr7N8WBFAn8Tuu5CEl3tCY2ZW Zq2/T2NSLK5XHU0m/QnYPgOYRwNqrt+/BFn55ksrmKtaBKtu2rPfQhM04vFxxGCjjg59 5xjbIUsQetv+SfgpmZCN2uQJEEK17qTgrfKaf0mLXKvSHqr3Jq2inmSpUDe5YoJr4pYk 8JiOoYVm0kw9NMPjxBXgp1RpOi1ukAxR+x2EEC5RTM5xsvdRIDSiLwH3bRfBnbTH8PKF Nhw8ZRLvbJlg4G648TfAxQ3Javu7L346h7ErXuRqTCypbOUL/RZhUDLC775Zn7SuxWiB yySA== X-Gm-Message-State: AOJu0YyPzQQJqncjWsl7d5JY+KlgIyNVYk4si64qK4DKzbpP1lwMsGW7 jo6U8zbZ5Dc6U96ovWbbc0KS3Q== X-Google-Smtp-Source: AGHT+IH7AowshQK4Duqp8ibktiyDdwIs6IoarHjYahYy+S9iUeHN2WlWrqwBXejS2HuZ1+xXUlqWsQ== X-Received: by 2002:a05:6358:2611:b0:142:e357:e777 with SMTP id l17-20020a056358261100b00142e357e777mr11796003rwc.25.1696682735217; Sat, 07 Oct 2023 05:45:35 -0700 (PDT) Received: from n37-019-243.byted.org ([180.184.51.134]) by smtp.gmail.com with ESMTPSA id d6-20020a17090ad3c600b00256799877ffsm5095388pjw.47.2023.10.07.05.45.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 07 Oct 2023 05:45:34 -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 v4 1/8] cgroup: Prepare for using css_task_iter_*() in BPF Date: Sat, 7 Oct 2023 20:45:15 +0800 Message-Id: <20231007124522.34834-2-zhouchuyi@bytedance.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20231007124522.34834-1-zhouchuyi@bytedance.com> References: <20231007124522.34834-1-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