From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qt1-f201.google.com (mail-qt1-f201.google.com [209.85.160.201]) (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 47CA233A701 for ; Thu, 9 Apr 2026 21:49:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775771385; cv=none; b=rP0L6Mz8/j9dHHVpjJPotPUPDRTPjpkz+skb91K5LZfj00GRENYTD8Gtyq7oYh7GT5ujymGfRIXDcP4bXcJPcHoX6PS4OIjXSmNi/FG67mZIAdjEVuwUGyc65dwXTLiT4UqZFsVdZG6EOIr7288brBkP/xuoSzF/s3FQbR3Y2QY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775771385; c=relaxed/simple; bh=nSo6aej+ukOVgv3jtn96voViCFdUZLg0a6AQV1Ez90M=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=Z6B+td9tqhqycw118dJJgqTk2zMXW2WePFt1lJQFwOMmz+iykTcmLc93W4buddf3ZIAhF/CKf0gZUAWRk+KymHbNp9N60AyIVVd5vdHIHzFIMuYFNhWf51atPZH3/yAdPLsWqI/oKbQFn3zHkCuFzuK0K36qd4pBDmq/PxzTFC8= 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=e9CDmw6G; arc=none smtp.client-ip=209.85.160.201 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="e9CDmw6G" Received: by mail-qt1-f201.google.com with SMTP id d75a77b69052e-50b4ca7e7c2so28879601cf.3 for ; Thu, 09 Apr 2026 14:49:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1775771383; x=1776376183; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=0ARy47czAXI1fX/UiSwJx6KtZ1ahNEm57GRGQ4HfmRQ=; b=e9CDmw6Gcaf+gSwrM5uztL6yBeCRgedzXXogF+Bo3ypzVRtrhg3sA4WS7Vb+wSx0Um YzQrutwAdEnPXx/91MftHNFe6pwbHpha4q0gv/f9gFPXEuGU+5Vu0LLrsebautZ9UGkH iS9m0dY4x6yEl7vW8wYHVinM5Za0iJJjaFn4ZGxiATSDMiJTc9TdFVHz3s5Kp+NoX8yh Xkavd6DtDERJffcxVgKApMD02u2a+iqJlz5mvICL1GZNEZ8Hud7Vjsj5mfBQh6dZWCOF LSd4zohq5mXHCK+/NzV7Sap/hFRsBwW0Jzi/WwcoAVFFRXSb/4qQxK61P4QeyFD4czNe ktKw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1775771383; x=1776376183; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=0ARy47czAXI1fX/UiSwJx6KtZ1ahNEm57GRGQ4HfmRQ=; b=CRgcJ7OXVqYGaITwlls5wrsrUyRGIRJkNITBQKSRvyPtQpGRM6HxpkmJmFZuoWOi4E mWjGgUAOt/nYGjN37Sj2ZXyOZG8h2i6YG7/59oVZdkVtPKSNyVqqYVFylLbBOONzBdUj W7iEEheT5LdtsZHZAj/2hGXWivyE2DxInmQc8gPq1vdxME0HmOkfjXnrubKPf5d4UnBu kBd7Tt+Y+vhEJIujByY83EvhWWHNSXS4H6xOhxwGU9iCi/D99nAz14EvXgWEmw/OblJN 0HwMRFDaRAVM6kcOkRwoVzIvJnLLVWSfMzDX1dMmIqRqH1Dbc/yoAptE3YT3XDLg9vhx QI4w== X-Forwarded-Encrypted: i=1; AJvYcCXA8nt5DA6nF0CgbGxkmbGwlPBFWc+N6l4p9posPctxrxcQB5gk5HcjBw6YU2vUckipANypt4o=@vger.kernel.org X-Gm-Message-State: AOJu0YyAA00pmjyb9i632TQG+sGwvGuGqRI5x0YsbRRtxZsf90WGw2Ji 49cszRMjFqnJ+jT6tZZQhMw2h8tK2FIrOK4KH3NpCIoivqs1MIefVjyXuIHpvxiTRRO832r7dUO ago77Qdg2GS6QPw== X-Received: from qtvo19.prod.google.com ([2002:ac8:7c53:0:b0:503:34fa:ca78]) (user=edumazet job=prod-delivery.src-stubby-dispatcher) by 2002:a05:622a:2285:b0:50b:465f:706c with SMTP id d75a77b69052e-50dd5ccfd69mr14525371cf.60.1775771383180; Thu, 09 Apr 2026 14:49:43 -0700 (PDT) Date: Thu, 9 Apr 2026 21:49:14 +0000 In-Reply-To: <20260409214914.3072827-1-edumazet@google.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260409214914.3072827-1-edumazet@google.com> X-Mailer: git-send-email 2.53.0.1213.gd9a14994de-goog Message-ID: <20260409214914.3072827-16-edumazet@google.com> Subject: [PATCH v2 net-next 15/15] 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 , Kuniyuki Iwashima , 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() annoations. 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 885a9bc859166dfb6d20aa0dfbb8f11194e02ba9..75030a834840cde3480722cc4214431625a7c7ee 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); } } } @@ -1770,8 +1770,8 @@ 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; } @@ -1851,12 +1851,14 @@ 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; + } + 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); @@ -1939,7 +1941,8 @@ 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) && @@ -2279,8 +2282,8 @@ 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; @@ -2294,10 +2297,11 @@ 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); @@ -2383,6 +2387,7 @@ 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); @@ -2400,14 +2405,15 @@ 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; -- 2.53.0.1213.gd9a14994de-goog