Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763017AbcLSPh1 (ORCPT ); Mon, 19 Dec 2016 10:37:27 -0500 Received: from mx08-00178001.pphosted.com ([91.207.212.93]:42997 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753882AbcLSPhU (ORCPT ); Mon, 19 Dec 2016 10:37:20 -0500 Subject: Re: [PATCH] stmmac: fix memory barriers To: Pavel Machek , , , , , , , References: <20161218203812.GA1012@amd> From: Giuseppe CAVALLARO Message-ID: <2f88bee3-779e-68d6-d117-74fdc640f2e5@st.com> Date: Mon, 19 Dec 2016 16:36:54 +0100 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.1.0 MIME-Version: 1.0 In-Reply-To: <20161218203812.GA1012@amd> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.52.139.54] X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-12-19_11:,, signatures=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3052 Lines: 86 On 12/18/2016 9:38 PM, Pavel Machek wrote: > > Fix up memory barriers in stmmac driver. They are meant to protect > against DMA engine, so smp_ variants are certainly wrong, and dma_ > variants are preferable. > > Signed-off-by: Pavel Machek Acked-by: Giuseppe Cavallaro > > diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c > index a340fc8..8816515 100644 > --- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c > +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c > @@ -334,7 +334,7 @@ static void dwmac4_rd_prepare_tx_desc(struct dma_desc *p, int is_fs, int len, > * descriptors for the same frame has to be set before, to > * avoid race condition. > */ > - wmb(); > + dma_wmb(); > > p->des3 = cpu_to_le32(tdes3); > } > @@ -377,7 +377,7 @@ static void dwmac4_rd_prepare_tso_tx_desc(struct dma_desc *p, int is_fs, > * descriptors for the same frame has to be set before, to > * avoid race condition. > */ > - wmb(); > + dma_wmb(); > > p->des3 = cpu_to_le32(tdes3); > } > diff --git a/drivers/net/ethernet/stmicro/stmmac/enh_desc.c b/drivers/net/ethernet/stmicro/stmmac/enh_desc.c > index ce97e52..f0d8632 100644 > --- a/drivers/net/ethernet/stmicro/stmmac/enh_desc.c > +++ b/drivers/net/ethernet/stmicro/stmmac/enh_desc.c > @@ -350,7 +350,7 @@ static void enh_desc_prepare_tx_desc(struct dma_desc *p, int is_fs, int len, > * descriptors for the same frame has to be set before, to > * avoid race condition. > */ > - wmb(); > + dma_wmb(); > > p->des0 = cpu_to_le32(tdes0); > } > diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c > index 3e40578..bb40382 100644 > --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c > +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c > @@ -2125,7 +2125,7 @@ static netdev_tx_t stmmac_tso_xmit(struct sk_buff *skb, struct net_device *dev) > * descriptor and then barrier is needed to make sure that > * all is coherent before granting the DMA engine. > */ > - smp_wmb(); > + dma_wmb(); > > if (netif_msg_pktdata(priv)) { > pr_info("%s: curr=%d dirty=%d f=%d, e=%d, f_p=%p, nfrags %d\n", > @@ -2338,7 +2338,7 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev) > * descriptor and then barrier is needed to make sure that > * all is coherent before granting the DMA engine. > */ > - smp_wmb(); > + dma_wmb(); > } > > netdev_sent_queue(dev, skb->len); > @@ -2443,14 +2443,14 @@ static inline void stmmac_rx_refill(struct stmmac_priv *priv) > netif_dbg(priv, rx_status, priv->dev, > "refill entry #%d\n", entry); > } > - wmb(); > + dma_wmb(); > > if (unlikely(priv->synopsys_id >= DWMAC_CORE_4_00)) > priv->hw->desc->init_rx_desc(p, priv->use_riwt, 0, 0); > else > priv->hw->desc->set_rx_owner(p); > > - wmb(); > + dma_wmb(); > > entry = STMMAC_GET_ENTRY(entry, DMA_RX_SIZE); > } >