From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 6AEC9C83F1B for ; Wed, 16 Jul 2025 08:38:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=ZaWeSIQ1ptx/KeTTpJD9e4ELx0X/wlrZF8/OCCCIU/U=; b=WLiLZQhPCu0gFoLCXBNEbRjMiH kRyQicKacLAwJXriOcULnoSnjtYgjIaiTts+DcHTBi2EqxX574FkNe4jc5JG+r4YffhXeaYj5aeeU IyDLkb2eAGBRZ6/1H8ZH1KdRUy5dEnCAuoR2k1apboePjHc08gQGLT8p19raoGV5HGEohHiMyuXm4 NCUc+Z7XLnr0JBeLqCkxTxiLPOiADMoYv49+Aos1AeNjTwTfvIaBhH4SP1SunanT8oSnXU0+lUc2r myg32B09s44fFwhNfr4nJXdKBn7lx1xnGVqFjO9Zfh3vvNAlLv/oXlILwlC9z7U21FwRbHS1q28hs jd8RtgSQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1ubxeV-00000007Bs5-1PLz; Wed, 16 Jul 2025 08:38:11 +0000 Received: from nyc.source.kernel.org ([2604:1380:45d1:ec00::3]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1ubxP5-000000079fM-2wSk for linux-arm-kernel@lists.infradead.org; Wed, 16 Jul 2025 08:22:16 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by nyc.source.kernel.org (Postfix) with ESMTP id F07F8A52F6F; Wed, 16 Jul 2025 08:22:14 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DAA6EC4CEF0; Wed, 16 Jul 2025 08:22:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1752654134; bh=cnOqqRyy8qapop2aj8Jh9qYqoK7bu5+GswzkuuErweY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=YxNr8dV8utIpB32/zJ1R+YimFzAuZwRROQZBqfJHoDS1ouPaDNML/T8mkaNtZMorC kPTe0Y1t6Iey7AUMZP7C5z0XxnTIjBMTw/w+h+6SFXB0B1AwAfN33HXIgy28zIE6Py RyPQ33zcZhyWh/Zbgw+mAuB4HhAhx+GgIkjvmpgzyIc9k5uJadbiBJyJ3TPXEiPZ+N gt+wfW/KeOkvC+pDiV/pYPoCG4OGTZgGyqAmSuTJyH1V1IuwYfH7Up4a+Z11t3vYYC a6VuvwUWYzY1djopIhfce3XbH4hsyUXakJfB45GOZK8PpEl6aE56MoeJ3BsFJ2cRnI MNn3jyoDwNqiw== Date: Wed, 16 Jul 2025 09:22:09 +0100 From: Simon Horman To: "G Thomas, Rohan" Cc: Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Maxime Coquelin , Alexandre Torgue , Serge Semin , Romain Gantois , netdev@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Matthew Gerlach Subject: Re: [PATCH net-next 3/3] net: stmmac: Set CIC bit only for TX queues with COE Message-ID: <20250716082209.GH721198@horms.kernel.org> References: <20250714-xgmac-minor-fixes-v1-0-c34092a88a72@altera.com> <20250714-xgmac-minor-fixes-v1-3-c34092a88a72@altera.com> <20250714134012.GN721198@horms.kernel.org> <9f4acd69-12ff-4b2f-bb3a-e8d401b23238@altera.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9f4acd69-12ff-4b2f-bb3a-e8d401b23238@altera.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250716_012215_868933_612C70D5 X-CRM114-Status: GOOD ( 29.08 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Jul 15, 2025 at 07:14:21PM +0530, G Thomas, Rohan wrote: > Hi Simon, > > Thanks for reviewing the patch. > > On 7/14/2025 7:10 PM, Simon Horman wrote: > > On Mon, Jul 14, 2025 at 03:59:19PM +0800, Rohan G Thomas via B4 Relay wrote: > > > From: Rohan G Thomas > > > > > > Currently, in the AF_XDP transmit paths, the CIC bit of > > > TX Desc3 is set for all packets. Setting this bit for > > > packets transmitting through queues that don't support > > > checksum offloading causes the TX DMA to get stuck after > > > transmitting some packets. This patch ensures the CIC bit > > > of TX Desc3 is set only if the TX queue supports checksum > > > offloading. > > > > > > Signed-off-by: Rohan G Thomas > > > Reviewed-by: Matthew Gerlach > > > > Hi Rohan, > > > > I notice that stmmac_xmit() handles a few other cases where > > checksum offload should not be requested via stmmac_prepare_tx_desc: > > > > csum_insertion = (skb->ip_summed == CHECKSUM_PARTIAL); > > /* DWMAC IPs can be synthesized to support tx coe only for a few tx > > * queues. In that case, checksum offloading for those queues that don't > > * support tx coe needs to fallback to software checksum calculation. > > * > > * Packets that won't trigger the COE e.g. most DSA-tagged packets will > > * also have to be checksummed in software. > > */ > > if (csum_insertion && > > (priv->plat->tx_queues_cfg[queue].coe_unsupported || > > !stmmac_has_ip_ethertype(skb))) { > > if (unlikely(skb_checksum_help(skb))) > > goto dma_map_err; > > csum_insertion = !csum_insertion; > > } > > > > Do we need to care about them in stmmac_xdp_xmit_zc() > > and stmmac_xdp_xmit_xdpf() too? > > This patch only addresses avoiding the TX DMA hang by ensuring the CIC > bit is only set when the queue supports checksum offload. For DSA tagged > packets checksum offloading is not supported by the DWMAC IPs but no TX > DMA hang. AFAIK, currently AF_XDP paths don't have equivalent handling > like skb_checksum_help(), since they operate on xdp buffers. So this > patch doesn't attempt to implement a sw fallback but just avoids DMA > stall. Ok, fair enough. As per Andrew's advice elsewhere in this thread. This patch also looks like it should be a fix for net, and should have a Fixes tag.