rt2x00: In debugfs frame dumping allow the TX descriptor to be part of the skb.

Preparation for futher cleanups in the area of properly maintaining the skb
data without fiddling with the skb->data pointer.
Signed-off-by: Gertjan van Wingerde <gwingerde@gmail.com>
Acked-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rt2x00/rt2x00debug.c

@@ -159,6 +159,7 @@ void rt2x00debug_dump_frame(struct rt2x00_dev *rt2x00dev,
 	struct sk_buff *skbcopy;
 	struct rt2x00dump_hdr *dump_hdr;
 	struct timeval timestamp;
+	u32 data_len;
 
 	do_gettimeofday(&timestamp);
 
@@ -170,7 +171,11 @@ void rt2x00debug_dump_frame(struct rt2x00_dev *rt2x00dev,
 		return;
 	}
 
-	skbcopy = alloc_skb(sizeof(*dump_hdr) + skbdesc->desc_len + skb->len,
+	data_len = skb->len;
+	if (skbdesc->flags & SKBDESC_DESC_IN_SKB)
+		data_len -= skbdesc->desc_len;
+
+	skbcopy = alloc_skb(sizeof(*dump_hdr) + skbdesc->desc_len + data_len,
 			    GFP_ATOMIC);
 	if (!skbcopy) {
 		DEBUG(rt2x00dev, "Failed to copy skb for dump.\n");
@@ -181,7 +186,7 @@ void rt2x00debug_dump_frame(struct rt2x00_dev *rt2x00dev,
 	dump_hdr->version = cpu_to_le32(DUMP_HEADER_VERSION);
 	dump_hdr->header_length = cpu_to_le32(sizeof(*dump_hdr));
 	dump_hdr->desc_length = cpu_to_le32(skbdesc->desc_len);
-	dump_hdr->data_length = cpu_to_le32(skb->len);
+	dump_hdr->data_length = cpu_to_le32(data_len);
 	dump_hdr->chip_rt = cpu_to_le16(rt2x00dev->chip.rt);
 	dump_hdr->chip_rf = cpu_to_le16(rt2x00dev->chip.rf);
 	dump_hdr->chip_rev = cpu_to_le16(rt2x00dev->chip.rev);
@@ -191,8 +196,9 @@ void rt2x00debug_dump_frame(struct rt2x00_dev *rt2x00dev,
 	dump_hdr->timestamp_sec = cpu_to_le32(timestamp.tv_sec);
 	dump_hdr->timestamp_usec = cpu_to_le32(timestamp.tv_usec);
 
-	memcpy(skb_put(skbcopy, skbdesc->desc_len), skbdesc->desc,
-	       skbdesc->desc_len);
+	if (!(skbdesc->flags & SKBDESC_DESC_IN_SKB))
+		memcpy(skb_put(skbcopy, skbdesc->desc_len), skbdesc->desc,
+		       skbdesc->desc_len);
 	memcpy(skb_put(skbcopy, skb->len), skb->data, skb->len);
 
 	skb_queue_tail(&intf->frame_dump_skbqueue, skbcopy);

drivers/net/wireless/rt2x00/rt2x00queue.h

@@ -94,12 +94,15 @@ enum data_queue_qid {
  *	mac80211 but was stripped for processing by the driver.
  * @SKBDESC_NOT_MAC80211: Frame didn't originate from mac80211,
  *	don't try to pass it back.
+ * @SKBDESC_DESC_IN_SKB: The descriptor is at the start of the
+ *	skb, instead of in the desc field.
  */
 enum skb_frame_desc_flags {
 	SKBDESC_DMA_MAPPED_RX = 1 << 0,
 	SKBDESC_DMA_MAPPED_TX = 1 << 1,
 	SKBDESC_IV_STRIPPED = 1 << 2,
 	SKBDESC_NOT_MAC80211 = 1 << 3,
+	SKBDESC_DESC_IN_SKB = 1 << 4,
 };
 
 /**