staging: vt6655: vnt_tx_packet Fix corrupted tx packets.

Move PSTxDesc->m_td1TD1 to inside spin locks.

if m_td1TD1.byTCR has TCR_EDP and TCR_STP are set, the interrupt handler will
try and complete the buffer before it is completed. Usually on the tail
of a burst of tx packets.

This results in a partially completed packet being transmitted or worse
sitll dead lock when skb is freed by the interrupt handler.

Set head_td->m_td1TD1.byTCR to 0 in first lock of vnt_tx_packet to stop
interrupt handler completing the buffer. Move Set TSR1 & ReqCount in
s_cbFillTxBufHead to the second lock.

cbReqCount is carried to the second lock in pTDInfo->dwReqCount without
the padding removed.

Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/vt6655/device_main.c

@@ -1232,7 +1232,7 @@ static int vnt_tx_packet(struct vnt_private *priv, struct sk_buff *skb)
 
 	head_td = priv->apCurrTD[dma_idx];
 
-	head_td->m_td1TD1.byTCR = (TCR_EDP|TCR_STP);
+	head_td->m_td1TD1.byTCR = 0;
 
 	head_td->pTDInfo->skb = skb;
 
@@ -1257,6 +1257,11 @@ static int vnt_tx_packet(struct vnt_private *priv, struct sk_buff *skb)
 
 	priv->bPWBitOn = false;
 
+	/* Set TSR1 & ReqCount in TxDescHead */
+	head_td->m_td1TD1.byTCR |= (TCR_STP | TCR_EDP | EDMSDU);
+	head_td->m_td1TD1.wReqCount =
+			cpu_to_le16((u16)head_td->pTDInfo->dwReqCount);
+
 	head_td->pTDInfo->byFlags = TD_FLAGS_NETIF_SKB;
 
 	if (dma_idx == TYPE_AC0DMA)

drivers/staging/vt6655/rxtx.c

@@ -1204,13 +1204,10 @@ s_cbFillTxBufHead(struct vnt_private *pDevice, unsigned char byPktType,
 
 	ptdCurr = (PSTxDesc)pHeadTD;
 
-	ptdCurr->pTDInfo->dwReqCount = cbReqCount - uPadding;
+	ptdCurr->pTDInfo->dwReqCount = cbReqCount;
 	ptdCurr->pTDInfo->dwHeaderLength = cbHeaderLength;
 	ptdCurr->pTDInfo->skb_dma = ptdCurr->pTDInfo->buf_dma;
 	ptdCurr->buff_addr = cpu_to_le32(ptdCurr->pTDInfo->skb_dma);
-	/* Set TSR1 & ReqCount in TxDescHead */
-	ptdCurr->m_td1TD1.byTCR |= (TCR_STP | TCR_EDP | EDMSDU);
-	ptdCurr->m_td1TD1.wReqCount = cpu_to_le16((unsigned short)(cbReqCount));
 
 	return cbHeaderLength;
 }