From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Malcolm Priestley Subject: [PATCH 4.0 068/148] staging: vt6655: vnt_tx_packet Correct TX order of OWNED_BY_NIC Date: Wed, 3 Jun 2015 21:08:58 +0900 Message-Id: <20150603114208.339160901@linuxfoundation.org> In-Reply-To: <20150603114205.337615117@linuxfoundation.org> References: <20150603114205.337615117@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Malcolm Priestley commit d65d2b25d2761153390df8026cca1a528d9b6c5a upstream. The state of m_td0TD0.f1Owner should change after the buff_addr has been filled otherwise the device grabs the buffer too early. m_td0TD0.f1Owner is protected by memory barriers on both sides of change. iTDUsed is best incremented after MACvTransmit. It appears that f1Owner actually polls to do the memory transfer. A back port patch will be needed for v3.19 Signed-off-by: Malcolm Priestley Signed-off-by: Greg Kroah-Hartman --- drivers/staging/vt6655/device_main.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) --- a/drivers/staging/vt6655/device_main.c +++ b/drivers/staging/vt6655/device_main.c @@ -1203,14 +1203,6 @@ static int vnt_tx_packet(struct vnt_priv if (dma_idx == TYPE_AC0DMA) head_td->pTDInfo->byFlags = TD_FLAGS_NETIF_SKB; - priv->iTDUsed[dma_idx]++; - - /* Take ownership */ - wmb(); - head_td->m_td0TD0.f1Owner = OWNED_BY_NIC; - - /* get Next */ - wmb(); priv->apCurrTD[dma_idx] = head_td->next; spin_unlock_irqrestore(&priv->lock, flags); @@ -1231,11 +1223,18 @@ static int vnt_tx_packet(struct vnt_priv head_td->buff_addr = cpu_to_le32(head_td->pTDInfo->skb_dma); + /* Poll Transmit the adapter */ + wmb(); + head_td->m_td0TD0.f1Owner = OWNED_BY_NIC; + wmb(); /* second memory barrier */ + if (head_td->pTDInfo->byFlags & TD_FLAGS_NETIF_SKB) MACvTransmitAC0(priv->PortOffset); else MACvTransmit0(priv->PortOffset); + priv->iTDUsed[dma_idx]++; + spin_unlock_irqrestore(&priv->lock, flags); return 0;