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 X-Spam-Level: X-Spam-Status: No, score=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3E81BC49EA3 for ; Mon, 28 Jun 2021 14:36:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2848E61C9B for ; Mon, 28 Jun 2021 14:36:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234637AbhF1Oib (ORCPT ); Mon, 28 Jun 2021 10:38:31 -0400 Received: from mail.kernel.org ([198.145.29.99]:43650 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235445AbhF1Og3 (ORCPT ); Mon, 28 Jun 2021 10:36:29 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 9009861CAC; Mon, 28 Jun 2021 14:30:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1624890638; bh=8w+9oueYapVKhPyZ+eIOgMXrcrtDNQfpPbh9OJYyziY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qIHCkShHSfFpnLxXHy4RmsnvTGTc5l3BXuZXTvQaPxlZ5R3vPRbIn3NIvy6J5o2PH I1qwV0ptfVJUFYAPLTfgzK6PigkBkucNJT8o87ls4JJQq/nPudiF5whkUC3T9iZg9X 8MyJAYntjOJx1CmGMOz0swAoNp73LcAC7haV9j9BJG/zk/mN6fdILJ+8BcKKW/pZhU WsZlNFGOIkzmMNQeT2AOvDU1xb4HfzGvorZO18j91t7TKdEaTtm+OhaLDsNWgZ5QPq /gA71Ya4E5TkWVnLdS4py4hBc3vGxo9ItSt/IJ5eGUJ4jD9xiYVfyGFR8qplBhoSwi qiEG7BRjkZiRA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Esben Haabendal , "David S . Miller" , Sasha Levin Subject: [PATCH 5.4 37/71] net: ll_temac: Add memory-barriers for TX BD access Date: Mon, 28 Jun 2021 10:29:30 -0400 Message-Id: <20210628143004.32596-38-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210628143004.32596-1-sashal@kernel.org> References: <20210628143004.32596-1-sashal@kernel.org> MIME-Version: 1.0 X-KernelTest-Patch: http://kernel.org/pub/linux/kernel/v5.x/stable-review/patch-5.4.129-rc1.gz X-KernelTest-Tree: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git X-KernelTest-Branch: linux-5.4.y X-KernelTest-Patches: git://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git X-KernelTest-Version: 5.4.129-rc1 X-KernelTest-Deadline: 2021-06-30T14:29+00:00 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Esben Haabendal [ Upstream commit 28d9fab458b16bcd83f9dd07ede3d585c3e1a69e ] Add a couple of memory-barriers to ensure correct ordering of read/write access to TX BDs. In xmit_done, we should ensure that reading the additional BD fields are only done after STS_CTRL_APP0_CMPLT bit is set. When xmit_done marks the BD as free by setting APP0=0, we need to ensure that the other BD fields are reset first, so we avoid racing with the xmit path, which writes to the same fields. Finally, making sure to read APP0 of next BD after the current BD, ensures that we see all available buffers. Signed-off-by: Esben Haabendal Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/net/ethernet/xilinx/ll_temac_main.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/xilinx/ll_temac_main.c b/drivers/net/ethernet/xilinx/ll_temac_main.c index 9b55fbdc3a7c..d3d9f7046913 100644 --- a/drivers/net/ethernet/xilinx/ll_temac_main.c +++ b/drivers/net/ethernet/xilinx/ll_temac_main.c @@ -770,12 +770,15 @@ static void temac_start_xmit_done(struct net_device *ndev) stat = be32_to_cpu(cur_p->app0); while (stat & STS_CTRL_APP0_CMPLT) { + /* Make sure that the other fields are read after bd is + * released by dma + */ + rmb(); dma_unmap_single(ndev->dev.parent, be32_to_cpu(cur_p->phys), be32_to_cpu(cur_p->len), DMA_TO_DEVICE); skb = (struct sk_buff *)ptr_from_txbd(cur_p); if (skb) dev_consume_skb_irq(skb); - cur_p->app0 = 0; cur_p->app1 = 0; cur_p->app2 = 0; cur_p->app3 = 0; @@ -784,6 +787,12 @@ static void temac_start_xmit_done(struct net_device *ndev) ndev->stats.tx_packets++; ndev->stats.tx_bytes += be32_to_cpu(cur_p->len); + /* app0 must be visible last, as it is used to flag + * availability of the bd + */ + smp_mb(); + cur_p->app0 = 0; + lp->tx_bd_ci++; if (lp->tx_bd_ci >= TX_BD_NUM) lp->tx_bd_ci = 0; @@ -810,6 +819,9 @@ static inline int temac_check_tx_bd_space(struct temac_local *lp, int num_frag) if (cur_p->app0) return NETDEV_TX_BUSY; + /* Make sure to read next bd app0 after this one */ + rmb(); + tail++; if (tail >= TX_BD_NUM) tail = 0; -- 2.30.2