staging: vt6655: vnt_tx_packet fix dma_idx selection.

commit c3125305 upstream.

There is still a problem that dma_idx is causing packets to
go onto the wrong tx path.

Protect dma_idx fully with the present first lock and
use pTDInfo->byFlags TD_FLAGS_NETIF_SKB to set MACvTransmit.
Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

drivers/staging/vt6655/device_main.c

@@ -1205,12 +1205,14 @@ static int vnt_tx_packet(struct vnt_private *priv, struct sk_buff *skb)
 {
 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
 	PSTxDesc head_td;
-	u32 dma_idx = TYPE_AC0DMA;
+	u32 dma_idx;
 	unsigned long flags;
 
 	spin_lock_irqsave(&priv->lock, flags);
 
-	if (!ieee80211_is_data(hdr->frame_control))
+	if (ieee80211_is_data(hdr->frame_control))
+		dma_idx = TYPE_AC0DMA;
+	else
 		dma_idx = TYPE_TXDMA0;
 
 	if (AVAIL_TD(priv, dma_idx) < 1) {
@@ -1224,6 +1226,9 @@ static int vnt_tx_packet(struct vnt_private *priv, struct sk_buff *skb)
 
 	head_td->pTDInfo->skb = skb;
 
+	if (dma_idx == TYPE_AC0DMA)
+		head_td->pTDInfo->byFlags = TD_FLAGS_NETIF_SKB;
+
 	priv->iTDUsed[dma_idx]++;
 
 	/* Take ownership */
@@ -1252,13 +1257,10 @@ 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);
 
-	if (dma_idx == TYPE_AC0DMA) {
-		head_td->pTDInfo->byFlags = TD_FLAGS_NETIF_SKB;
-
+	if (head_td->pTDInfo->byFlags & TD_FLAGS_NETIF_SKB)
 		MACvTransmitAC0(priv->PortOffset);
-	} else {
+	else
 		MACvTransmit0(priv->PortOffset);
-	}
 
 	spin_unlock_irqrestore(&priv->lock, flags);