From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 352D15372DE; Wed, 30 Sep 2026 17:51:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790790706; cv=none; b=NcojUkV4Pp8o5Qxs4XkrEQ3IUSSD3gtoScfuSBQhb70g/VU6vDXcgc/q9WlbcjTlN5dHIQVACBk7tCzEcGdlvEKOeAsk8evsLbSvSsgMTCjLd50k1awz7sqxViqqLcY7uzpGAdBzque9mupI/Dayw115MVy7jfUmnstLINIpNAg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790790706; c=relaxed/simple; bh=ObZms8D8vIA+MABUuyqugwNt+D85YQpsB9F1hpfkBZU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=egim1jpgaDIS3XipS2oc5WAmfGR1cUHK5kuyPMSwCfqGAiSldqtIPjCyfEG4qqW2beLiARObcFukHuEE1qRpm+FRP21yX5I+nACnP/j5pThdz9/IftBAWsfc/+G6OsElueMIYAKDiWE2pnbWj3BlCX4+BJGnSKaJ6J6ZTokC5WM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=dJhK66GP; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="dJhK66GP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7E21D1F000FF; Wed, 30 Sep 2026 17:51:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790790705; bh=jOC1NGPSlggdpadHLarFRDCi6mJIFjGgIiYJvgcogjg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=dJhK66GPUFoGYujhkorpYKdfVhPsMALLf46LC9rfrCVyF8Qmi2/2yq8CIj+1bR09w txebsV8ufsYvzs/iXG8ttmtVjUierArLXmTPQtS9OmXiy5eLxZaA3Wad6i6UUCH0qk nlTJ+gfG4FW8ZQdxynFjY/FBVGQtwBNI+mkrO+J8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.15 046/752] net/sched: sch_drr: make cl->quantum lockless Date: Wed, 30 Sep 2026 17:18:36 +0200 Message-ID: <20260930152359.149653316@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152358.131179731@linuxfoundation.org> References: <20260930152358.131179731@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit a4d880b85089e12a5f2e8e2fee386310cec5b99a ] cl->quantum does not need to be protected by RTNL or qdisc spinlock. Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20260519094618.2632073-3-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/sched/sch_drr.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/net/sched/sch_drr.c b/net/sched/sch_drr.c index a2b9802d41c01..01198fe915052 100644 --- a/net/sched/sch_drr.c +++ b/net/sched/sch_drr.c @@ -99,10 +99,8 @@ static int drr_change_class(struct Qdisc *sch, u32 classid, u32 parentid, } } - sch_tree_lock(sch); if (tb[TCA_DRR_QUANTUM]) - cl->quantum = quantum; - sch_tree_unlock(sch); + WRITE_ONCE(cl->quantum, quantum); return 0; } @@ -252,7 +250,7 @@ static int drr_dump_class(struct Qdisc *sch, unsigned long arg, nest = nla_nest_start_noflag(skb, TCA_OPTIONS); if (nest == NULL) goto nla_put_failure; - if (nla_put_u32(skb, TCA_DRR_QUANTUM, cl->quantum)) + if (nla_put_u32(skb, TCA_DRR_QUANTUM, READ_ONCE(cl->quantum))) goto nla_put_failure; return nla_nest_end(skb, nest); @@ -371,7 +369,7 @@ static int drr_enqueue(struct sk_buff *skb, struct Qdisc *sch, if (!cl_is_active(cl)) { list_add_tail(&cl->alist, &q->active); - WRITE_ONCE(cl->deficit, cl->quantum); + WRITE_ONCE(cl->deficit, READ_ONCE(cl->quantum)); } sch->qstats.backlog += len; @@ -412,7 +410,7 @@ static struct sk_buff *drr_dequeue(struct Qdisc *sch) return skb; } - WRITE_ONCE(cl->deficit, cl->deficit + cl->quantum); + WRITE_ONCE(cl->deficit, cl->deficit + READ_ONCE(cl->quantum)); list_move_tail(&cl->alist, &q->active); } out: -- 2.53.0