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 E9375C49EA3 for ; Mon, 28 Jun 2021 14:29:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D681A61C7E for ; Mon, 28 Jun 2021 14:29:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233969AbhF1Obg (ORCPT ); Mon, 28 Jun 2021 10:31:36 -0400 Received: from mail.kernel.org ([198.145.29.99]:36912 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234823AbhF1Oab (ORCPT ); Mon, 28 Jun 2021 10:30:31 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id E0AEA61CC4; Mon, 28 Jun 2021 14:26:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1624890415; bh=stz5r8xqtps6azfB/g+KpMjwljvXV6hjgWBN+qI08/Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=p4vUK1KsHCdyJVh7VqTPDXzzA2w+6dLFA37NEAfZuEldmcWXDlouj3S4fih48EvZv yaF1EnuYHDk7pa81UUGkt9e/sAMiF2lNdVJWChXUhLM/HqSe2sqiIZAbjYetH+ZLja kKly8OPlBjUI85LlawFMJHD2r+MKQ2PXq/czErMpydPRaWupEBJsAdDpI/sAe/fdyy dbtAgU3567YPcnLooyLn7waxqrD0R7lOH2n2KmFlgaQ3iyFCaS3bOWYRxo5ZnV9For oB1oTmfJjk0ye/q2yJD91XXJhaJMixlqzo0A9SfzfN1vU2e7CVaHjjwtRAidzK2p4V ugaqUlj+8cGbg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Esben Haabendal , "David S . Miller" , Sasha Levin Subject: [PATCH 5.10 055/101] net: ll_temac: Add memory-barriers for TX BD access Date: Mon, 28 Jun 2021 10:25:21 -0400 Message-Id: <20210628142607.32218-56-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210628142607.32218-1-sashal@kernel.org> References: <20210628142607.32218-1-sashal@kernel.org> MIME-Version: 1.0 X-KernelTest-Patch: http://kernel.org/pub/linux/kernel/v5.x/stable-review/patch-5.10.47-rc1.gz X-KernelTest-Tree: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git X-KernelTest-Branch: linux-5.10.y X-KernelTest-Patches: git://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git X-KernelTest-Version: 5.10.47-rc1 X-KernelTest-Deadline: 2021-06-30T14:25+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 01bb36e7cff0..b105e1d35d15 100644 --- a/drivers/net/ethernet/xilinx/ll_temac_main.c +++ b/drivers/net/ethernet/xilinx/ll_temac_main.c @@ -774,12 +774,15 @@ 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; @@ -788,6 +791,12 @@ 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 >= lp->tx_bd_num) lp->tx_bd_ci = 0; @@ -814,6 +823,9 @@ 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 >= lp->tx_bd_num) tail = 0; -- 2.30.2