From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754179AbbFQXGz (ORCPT ); Wed, 17 Jun 2015 19:06:55 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:35288 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932960AbbFQW0d (ORCPT ); Wed, 17 Jun 2015 18:26:33 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Malcolm Priestley , Greg Kroah-Hartman , Kamal Mostafa Subject: [PATCH 3.19.y-ckt 127/146] staging: vt6655: vnt_tx_packet Correct TX order of OWNED_BY_NIC Date: Wed, 17 Jun 2015 15:23:52 -0700 Message-Id: <1434579851-1719-128-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1434579851-1719-1-git-send-email-kamal@canonical.com> References: <1434579851-1719-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.19 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.19.8-ckt2 -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 Signed-off-by: Kamal Mostafa --- drivers/staging/vt6655/device_main.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) diff --git a/drivers/staging/vt6655/device_main.c b/drivers/staging/vt6655/device_main.c index 7d9f563..f6dc6a4 100644 --- a/drivers/staging/vt6655/device_main.c +++ b/drivers/staging/vt6655/device_main.c @@ -1229,14 +1229,6 @@ static int vnt_tx_packet(struct vnt_private *priv, struct sk_buff *skb) 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); @@ -1257,11 +1249,18 @@ static int vnt_tx_packet(struct vnt_private *priv, struct sk_buff *skb) 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; -- 1.9.1