From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 9E0B1341ABD; Tue, 26 Aug 2025 13:59:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756216763; cv=none; b=DcOpHZFPxdtu/u8aRieCN6AGoh+ab4SyxRGiAgCcXGHKIasNQPHVGVUAVXkiB3ARUJcsev36Ek8uIcAW0fVrIuB4t2OTVuIszPe9cg86C79X2hGBHm5PFSffa4vwJznzrxcO8aEQ7nHj6khn7+KpPIDphWcwnZXopUyqMcyV588= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756216763; c=relaxed/simple; bh=Onbwkq/hRI0g6zeSmnFthrLXJQlGVDg6jiaqjJV8+Is=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=d127zV7sY9ogC8sufomH4n297b6mbMtnlZSyqmXFHUjyet10kD0q2TEB0emthJc3aVdvarjAjlNQ6k3T6kB4THoFYZvxXgqAiO91E3qeg6mmLTOtFgV51xR0ALSfnIwCTXT/hIVe1o+K63LmHVcivQtnxmRadiLA10svwk1/bJg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=dSib+Vtb; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="dSib+Vtb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CED4BC4CEF1; Tue, 26 Aug 2025 13:59:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1756216763; bh=Onbwkq/hRI0g6zeSmnFthrLXJQlGVDg6jiaqjJV8+Is=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dSib+VtbL6CPPJmzdiRWC+v4JgBHxkYgixQdcAngc/ryVJWcebbRiLnE4C+uXrCPi HPaqB9l7W5LHMYTHzGkNB84GnwiVGYIyHOU6o2/Bubbt4dP7U97UUiqypwpDMLbBje BNVuqD7KY30J8Th85NWLkiPlnwnK86qT/mOKnvs8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Gerrard Tai , Cong Wang , Simon Horman , Jamal Hadi Salim , Paolo Abeni Subject: [PATCH 5.15 504/644] sch_hfsc: make hfsc_qlen_notify() idempotent Date: Tue, 26 Aug 2025 13:09:55 +0200 Message-ID: <20250826110958.987995775@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250826110946.507083938@linuxfoundation.org> References: <20250826110946.507083938@linuxfoundation.org> User-Agent: quilt/0.68 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: Cong Wang commit 51eb3b65544c9efd6a1026889ee5fb5aa62da3bb upstream. hfsc_qlen_notify() is not idempotent either and not friendly to its callers, like fq_codel_dequeue(). Let's make it idempotent to ease qdisc_tree_reduce_backlog() callers' life: 1. update_vf() decreases cl->cl_nactive, so we can check whether it is non-zero before calling it. 2. eltree_remove() always removes RB node cl->el_node, but we can use RB_EMPTY_NODE() + RB_CLEAR_NODE() to make it safe. Reported-by: Gerrard Tai Signed-off-by: Cong Wang Reviewed-by: Simon Horman Link: https://patch.msgid.link/20250403211033.166059-4-xiyou.wangcong@gmail.com Acked-by: Jamal Hadi Salim Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman --- net/sched/sch_hfsc.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/net/sched/sch_hfsc.c +++ b/net/sched/sch_hfsc.c @@ -209,7 +209,10 @@ eltree_insert(struct hfsc_class *cl) static inline void eltree_remove(struct hfsc_class *cl) { - rb_erase(&cl->el_node, &cl->sched->eligible); + if (!RB_EMPTY_NODE(&cl->el_node)) { + rb_erase(&cl->el_node, &cl->sched->eligible); + RB_CLEAR_NODE(&cl->el_node); + } } static inline void @@ -1231,7 +1234,8 @@ hfsc_qlen_notify(struct Qdisc *sch, unsi /* vttree is now handled in update_vf() so that update_vf(cl, 0, 0) * needs to be called explicitly to remove a class from vttree. */ - update_vf(cl, 0, 0); + if (cl->cl_nactive) + update_vf(cl, 0, 0); if (cl->cl_flags & HFSC_RSC) eltree_remove(cl); }