From patchwork Mon Apr 14 15:45:50 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jesper Dangaard Brouer X-Patchwork-Id: 14050643 X-Patchwork-Delegate: kuba@kernel.org 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 B5EB31F92E; Mon, 14 Apr 2025 15:45:55 +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=1744645555; cv=none; b=Jvh21GGRdGj9lyqt13bl7DbCHzg63/HQ3Aspn7NeN961+Ub2FMvRXuUMTBAKGeQC5pFSWNMts2i3oW6t9+M9ikXIHMnMdjjP7qR2Scd7ALxC0LHxk9hpt/rH7XDnSS7La6IQMlNUqJ+03rZDaqZn9kVZseAOsRhpOXQUjCLkAQ8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744645555; c=relaxed/simple; bh=qW/iEZSmptKVmguSwrimgXAbe5PaLzBos/5ELdpZOA8=; h=Subject:From:To:Cc:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=DzGLaadcBkTpArf9vOVlgHrUnRXzA0P3F6tygdTknspO9yvPUz9ix/lAul2Q7LgNPFG95xcMuMl8ogocSPoSaGSyKUjAuVNXJS8IdxnCqB7ybE4hDBgliUAZTxEd10qiTxMU1f71pf2vESrWGai+n8WHcv2CPBBsqZ/pd/veIoY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mQXp6TNE; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="mQXp6TNE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DDAFFC4CEE2; Mon, 14 Apr 2025 15:45:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1744645555; bh=qW/iEZSmptKVmguSwrimgXAbe5PaLzBos/5ELdpZOA8=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=mQXp6TNEHs+NyrWQgdOlD5Apw/dxN/vjUXmXOxA+ZkrX556AnUm4KiKhjTVweC5I1 0ny8tuF8+Rwyxc/AokzBdFB2AYzT1AtGPwvm1448ZI/Z1vBiX+w6LWtvqFBSMAdFz3 YEHJWFMQjfdblwvPtkWKzF+x1szTSqa4kixzKt3rKQXE4nRjMwETaifGtU1VL0ENnV dm5wThcJetPbZ1EIPBMx24cGIsSYOmKTL96oTE3WbKtJipiFLHt3Wyh301roAjjtF0 JpbX6aiyi85YHcFH93vrRYq1usTV5v2esQwxDAtOyhNWUJWKCdcrESJ6KBiySNnHFC 4Mc8HLyXXDDlw== Subject: [PATCH net-next RFC V3 1/2] net: sched: generalize check for no-op qdisc on TX queue From: Jesper Dangaard Brouer To: netdev@vger.kernel.org, Jakub Kicinski Cc: Jesper Dangaard Brouer , bpf@vger.kernel.org, tom@herbertland.com, Eric Dumazet , "David S. Miller" , Paolo Abeni , =?utf-8?q?Toke_H=C3=B8iland-J=C3=B8rgensen?= , dsahern@kernel.org, makita.toshiaki@lab.ntt.co.jp, kernel-team@cloudflare.com Date: Mon, 14 Apr 2025 17:45:50 +0200 Message-ID: <174464555063.20396.9545196538212416415.stgit@firesoul> In-Reply-To: <174464549885.20396.6987653753122223942.stgit@firesoul> References: <174464549885.20396.6987653753122223942.stgit@firesoul> User-Agent: StGit/1.5 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org X-Patchwork-State: RFC WARNING: Testing show this is NOT correct! - I need help figuring out why this patch is incorrect. - Testing against &noop_qdisc is not the same as q->enqueue == NULL - I copied test (txq->qdisc == &noop_qdisc) from qdisc_tx_is_noop - Q: is qdisc_tx_is_noop() function incorrect? The vrf driver includes an open-coded check to determine whether a TX queue (netdev_queue) has a real qdisc attached. This is done by testing whether qdisc->enqueue is NULL, which is functionally equivalent to checking whether the qdisc is &noop_qdisc. This equivalence stems from noqueue_init(), which explicitly clears the enqueue pointer to signal no-op behavior to __dev_queue_xmit(). This patch introduces a shared helper, qdisc_txq_is_noop(), to clarify intent and make this logic reusable. The vrf driver is updated to use this new helper. Subsequent patches will make further use of this helper in other drivers, such as veth. This is a non-functional change. Signed-off-by: Jesper Dangaard Brouer --- drivers/net/vrf.c | 4 +--- include/net/sch_generic.h | 7 ++++++- 2 files changed, 7 insertions(+), 4 deletions(-) diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c index 7168b33adadb..f0a24fc85945 100644 --- a/drivers/net/vrf.c +++ b/drivers/net/vrf.c @@ -343,15 +343,13 @@ static int vrf_ifindex_lookup_by_table_id(struct net *net, u32 table_id) static bool qdisc_tx_is_default(const struct net_device *dev) { struct netdev_queue *txq; - struct Qdisc *qdisc; if (dev->num_tx_queues > 1) return false; txq = netdev_get_tx_queue(dev, 0); - qdisc = rcu_access_pointer(txq->qdisc); - return !qdisc->enqueue; + return qdisc_txq_is_noop(txq); } /* Local traffic destined to local address. Reinsert the packet to rx diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h index d48c657191cd..a1f5560350a6 100644 --- a/include/net/sch_generic.h +++ b/include/net/sch_generic.h @@ -803,6 +803,11 @@ static inline bool qdisc_tx_changing(const struct net_device *dev) return false; } +static inline bool qdisc_txq_is_noop(const struct netdev_queue *txq) +{ + return rcu_access_pointer(txq->qdisc) == &noop_qdisc; +} + /* Is the device using the noop qdisc on all queues? */ static inline bool qdisc_tx_is_noop(const struct net_device *dev) { @@ -810,7 +815,7 @@ static inline bool qdisc_tx_is_noop(const struct net_device *dev) for (i = 0; i < dev->num_tx_queues; i++) { struct netdev_queue *txq = netdev_get_tx_queue(dev, i); - if (rcu_access_pointer(txq->qdisc) != &noop_qdisc) + if (!qdisc_txq_is_noop(txq)) return false; } return true;