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authorMalcolm Priestley <tvboxspy@gmail.com>2015-04-21 22:33:00 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-05-08 14:35:22 +0200
commitd65d2b25d2761153390df8026cca1a528d9b6c5a (patch)
treeb4f7a3c020fd6c2981281b56f912c7e5de447a9b /drivers/staging
parentad3fee9b17b90b8f1ac94b615111b2f14dd90adb (diff)
staging: vt6655: vnt_tx_packet Correct TX order of OWNED_BY_NIC
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 <tvboxspy@gmail.com> Cc: <stable@vger.kernel.org> # v4.0+ Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/staging')
-rw-r--r--drivers/staging/vt6655/device_main.c15
1 files changed, 7 insertions, 8 deletions
diff --git a/drivers/staging/vt6655/device_main.c b/drivers/staging/vt6655/device_main.c
index c81776363d8e..930bbbebc102 100644
--- a/drivers/staging/vt6655/device_main.c
+++ b/drivers/staging/vt6655/device_main.c
@@ -1206,14 +1206,6 @@ 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);
@@ -1234,11 +1226,18 @@ 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;