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Commit 3ee54a07 authored by Ivo van Doorn's avatar Ivo van Doorn Committed by John W. Linville
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rt2x00: Map extra_tx_headroom to DMA 



If a driver requests additional headroom it should
be mapped to DMA as well because it will be send to
the hardware as well (as form of extra descriptor).

Signed-off-by: default avatarIvo van Doorn <IvDoorn@gmail.com>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 0262ab0d

drivers/net/wireless/rt2x00/rt2x00queue.c

+21 −3
Original line number Diff line number Diff line
@@ -100,8 +100,21 @@ void rt2x00queue_map_txskb(struct rt2x00_dev *rt2x00dev, struct sk_buff *skb) 
{

	struct skb_frame_desc *skbdesc = get_skb_frame_desc(skb);



	skbdesc->skb_dma = dma_map_single(rt2x00dev->dev, skb->data, skb->len,

					  DMA_TO_DEVICE);

	/*

	 * If device has requested headroom, we should make sure that

	 * is also mapped to the DMA so it can be used for transfering

	 * additional descriptor information to the hardware.

	 */

	skb_push(skb, rt2x00dev->hw->extra_tx_headroom);



	skbdesc->skb_dma =

	    dma_map_single(rt2x00dev->dev, skb->data, skb->len, DMA_TO_DEVICE);



	/*

	 * Restore data pointer to original location again.

	 */

	skb_pull(skb, rt2x00dev->hw->extra_tx_headroom);



	skbdesc->flags |= SKBDESC_DMA_MAPPED_TX;

}

EXPORT_SYMBOL_GPL(rt2x00queue_map_txskb);
@@ -117,7 +130,12 @@ void rt2x00queue_unmap_skb(struct rt2x00_dev *rt2x00dev, struct sk_buff *skb) 
	}



	if (skbdesc->flags & SKBDESC_DMA_MAPPED_TX) {

		dma_unmap_single(rt2x00dev->dev, skbdesc->skb_dma, skb->len,

		/*

		 * Add headroom to the skb length, it has been removed

		 * by the driver, but it was actually mapped to DMA.

		 */

		dma_unmap_single(rt2x00dev->dev, skbdesc->skb_dma,

				 skb->len + rt2x00dev->hw->extra_tx_headroom,

				 DMA_TO_DEVICE);

		skbdesc->flags &= ~SKBDESC_DMA_MAPPED_TX;

	}