From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qt1-f202.google.com (mail-qt1-f202.google.com [209.85.160.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B3DFD2ED17B for ; Fri, 1 May 2026 06:42:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777617773; cv=none; b=sCvVIIiAKhXq3vHsqGbHklHtgp/jgjX0TOD3V7K6n1FrcsGo7X26/FbOTuoBS4JupjpkdbxLcAGUDrmPYgVcdCSuwOMQN+H9VHMGYQMzZipWHqncovkDkGaFrzhrhx3Zs5NRH56JsHBQLSuFQ8yXPxZ7zTRfdNw7DW+8XsAFUaI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777617773; c=relaxed/simple; bh=FEWrGNNf+Xq36oGSBKfECMKwsWtEtMeg9O8Y/oSXqV4=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=IIXE5Kv0WLtw12hhmEV/nDWaNWhgRUXSrBrNo7CkrytjaTyzHLYvpFATq4LefOF1Ejqa7mMvIu/hqj9ra5KxE9630MbE4NWJL9iIunaZfiMUSf5E1XYgfgksfaX3HorBnXa+tV0/YxZiF9rCXr/Z/iyYH9QLLitsfWmuSuckPF4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--edumazet.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=fE3OiIzs; arc=none smtp.client-ip=209.85.160.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--edumazet.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="fE3OiIzs" Received: by mail-qt1-f202.google.com with SMTP id d75a77b69052e-50d9a6a853bso30124961cf.0 for ; Thu, 30 Apr 2026 23:42:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1777617770; x=1778222570; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=GbMc9ghKwk6SefPtqeBtKp4E75ftKxftebjoBFl4Itg=; b=fE3OiIzsKZF2eR/uLcSXnB+o51AEfkoPXLsUfz+98Nk5TD4zK2eJGF8zsc7nwp5Kn8 ZS5pm7l9njvxuaZ23vSXROx5l07JzypfUQtKxVFTIO0GE5KBGbqG9O/a3hGiK3qUxNOQ 4egSCcX5pEV1dNOR+fHX0C1Mv0Jix5tg69ByDpwIRRVpsXCzGfaS7gPBR7P1V31iWalR /1v8ygz1+ypGK5SZObdDuNbgfqRsrHwqrjoUjwIdPUHu4O9vTSBkMpP4lKuQ0dg7cwJ1 IqRGKsVL6lc6YBLuurMYCRp8QixHz7+AKiIhlcLOnMTw6mAxBCsYW4YREKR5wbjQKVVb N8DA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1777617770; x=1778222570; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=GbMc9ghKwk6SefPtqeBtKp4E75ftKxftebjoBFl4Itg=; b=srBet/fCeFvPNWehQ6+ZSurSoxCs3EgC1XScnLYIfp8lgK7TS2Q/ioIJ2KExumQ7nz mmxDBshS4Z4nzGSLZYsEkE+wZe6cv3Xs6RqYPwKVqnEifugGrrcuXWw5bY1694PgigVc 0CbKYK/uo9VqzvzFgGFMZ5HArhPaQBfaRxddBnQ1VQjaeOck80XtI9pugGWaSwGkETRW 18W8c3jx035nVdHyXRtP5A0TTiSKdkmCiQUPereYqsrngwbhu3+PArg4vA1q7+p4MIZd zSzVbL5zY1DP9z7xcxQSoZmg3afg/x2dzwxdREQemcONtG0roCiN5L3bNpqgNYW/v0DL iFyg== X-Forwarded-Encrypted: i=1; AFNElJ8jy5Hc0pwyp5XGwrja/HRxydoMHJ9gkLPxwwBTYDgbnCcP2nnwtXiTbcHENEeGLAXmKHt+BlQ=@vger.kernel.org X-Gm-Message-State: AOJu0YzE9bjSZ/BBP/MD9U1krwAVt8lAk8B15fH9xEyZ7woTkvT5Zov/ 1cmun+EzVfgoaEAiricJo4soFM0wi+FPoQUgqO6CQe+nytZ6tQZJEJ0ol9Q4n6TRFoXnDQeHVFT gCfU238bWwiUKUA== X-Received: from qtqt2.prod.google.com ([2002:ac8:7602:0:b0:50f:b9af:ace1]) (user=edumazet job=prod-delivery.src-stubby-dispatcher) by 2002:a05:622a:4246:b0:50e:5c31:5d56 with SMTP id d75a77b69052e-5103e80138bmr24215601cf.6.1777617770489; Thu, 30 Apr 2026 23:42:50 -0700 (PDT) Date: Fri, 1 May 2026 06:42:47 +0000 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.54.0.545.g6539524ca2-goog Message-ID: <20260501064247.2027688-1-edumazet@google.com> Subject: [PATCH net-next] net/sched: taprio: prepare taprio_dump() for RTNL removal From: Eric Dumazet To: "David S . Miller" , Jakub Kicinski , Paolo Abeni Cc: Simon Horman , Jamal Hadi Salim , Jiri Pirko , netdev@vger.kernel.org, eric.dumazet@gmail.com, Eric Dumazet Content-Type: text/plain; charset="UTF-8" We soon will no longer hold RTNL in qdisc dumps. Add READ_ONCE()/WRITE_ONCE() annotations. Note: taprio already uses RCU to protect most of its fields. Signed-off-by: Eric Dumazet --- net/sched/sch_taprio.c | 42 ++++++++++++++++++++++++------------------ 1 file changed, 24 insertions(+), 18 deletions(-) diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c index 45245157e00a69311304f8c69f9ee9d80bc4f4d8..71b690e1974dad8fbab7e12998e03f86a0847a98 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -308,10 +308,10 @@ static void taprio_update_queue_max_sdu(struct taprio_sched *q, if (max_sdu != U32_MAX) { sched->max_frm_len[tc] = max_sdu + dev->hard_header_len; - sched->max_sdu[tc] = max_sdu; + WRITE_ONCE(sched->max_sdu[tc], max_sdu); } else { sched->max_frm_len[tc] = U32_MAX; /* never oversized */ - sched->max_sdu[tc] = 0; + WRITE_ONCE(sched->max_sdu[tc], 0); } } } @@ -1771,8 +1771,8 @@ static int taprio_parse_tc_entries(struct Qdisc *sch, } for (tc = 0; tc < TC_QOPT_MAX_QUEUE; tc++) { - q->max_sdu[tc] = max_sdu[tc]; - q->fp[tc] = fp[tc]; + WRITE_ONCE(q->max_sdu[tc], max_sdu[tc]); + WRITE_ONCE(q->fp[tc], fp[tc]); if (fp[tc] != TC_FP_EXPRESS) have_preemption = true; } @@ -1852,12 +1852,14 @@ static int taprio_change(struct Qdisc *sch, struct nlattr *opt, return -EINVAL; } - if (q->flags != TAPRIO_FLAGS_INVALID && q->flags != taprio_flags) { - NL_SET_ERR_MSG_MOD(extack, - "Changing 'flags' of a running schedule is not supported"); - return -EOPNOTSUPP; + if (q->flags != taprio_flags) { + if (q->flags != TAPRIO_FLAGS_INVALID) { + NL_SET_ERR_MSG_MOD(extack, + "Changing 'flags' of a running schedule is not supported"); + return -EOPNOTSUPP; + } + WRITE_ONCE(q->flags, taprio_flags); } - q->flags = taprio_flags; /* Needed for length_to_duration() during netlink attribute parsing */ taprio_set_picos_per_byte(dev, q, extack); @@ -1940,7 +1942,8 @@ static int taprio_change(struct Qdisc *sch, struct nlattr *opt, goto unlock; } - q->txtime_delay = nla_get_u32(tb[TCA_TAPRIO_ATTR_TXTIME_DELAY]); + WRITE_ONCE(q->txtime_delay, + nla_get_u32(tb[TCA_TAPRIO_ATTR_TXTIME_DELAY])); } if (!TXTIME_ASSIST_IS_ENABLED(q->flags) && @@ -2283,8 +2286,8 @@ static int dump_schedule(struct sk_buff *msg, } static int taprio_dump_tc_entries(struct sk_buff *skb, - struct taprio_sched *q, - struct sched_gate_list *sched) + const struct taprio_sched *q, + const struct sched_gate_list *sched) { struct nlattr *n; int tc; @@ -2298,10 +2301,11 @@ static int taprio_dump_tc_entries(struct sk_buff *skb, goto nla_put_failure; if (nla_put_u32(skb, TCA_TAPRIO_TC_ENTRY_MAX_SDU, - sched->max_sdu[tc])) + READ_ONCE(sched->max_sdu[tc]))) goto nla_put_failure; - if (nla_put_u32(skb, TCA_TAPRIO_TC_ENTRY_FP, q->fp[tc])) + if (nla_put_u32(skb, TCA_TAPRIO_TC_ENTRY_FP, + READ_ONCE(q->fp[tc]))) goto nla_put_failure; nla_nest_end(skb, n); @@ -2387,6 +2391,7 @@ static int taprio_dump(struct Qdisc *sch, struct sk_buff *skb) struct sched_gate_list *oper, *admin; struct tc_mqprio_qopt opt = { 0 }; struct nlattr *nest, *sched_nest; + u32 txtime_delay; mqprio_qopt_reconstruct(dev, &opt); @@ -2404,14 +2409,15 @@ static int taprio_dump(struct Qdisc *sch, struct sk_buff *skb) if (q->flags && nla_put_u32(skb, TCA_TAPRIO_ATTR_FLAGS, q->flags)) goto options_error; - if (q->txtime_delay && - nla_put_u32(skb, TCA_TAPRIO_ATTR_TXTIME_DELAY, q->txtime_delay)) + txtime_delay = READ_ONCE(q->txtime_delay); + if (txtime_delay && + nla_put_u32(skb, TCA_TAPRIO_ATTR_TXTIME_DELAY, txtime_delay)) goto options_error; rcu_read_lock(); - oper = rtnl_dereference(q->oper_sched); - admin = rtnl_dereference(q->admin_sched); + oper = rcu_dereference(q->oper_sched); + admin = rcu_dereference(q->admin_sched); if (oper && taprio_dump_tc_entries(skb, q, oper)) goto options_error_rcu; -- 2.54.0.545.g6539524ca2-goog