network device driver - copy skb data to dma region

[Guest meerkat]

Hi,

 

Mapping the skb data to dma sometimes includes a bounce buffer (if the skb is out of the dma area)

My dma bitmask is unusual, and so I'm getting a lot of those bounce buffers.

My question is -

Is there a way to make sure that the skb is allocated in my dma region before I get it in the xmit function? This way I can keep the zero-copy in the tx, and avoid the bounce buffer at the same time.

Only 2 options I came up with are:

1. map the skb data (--> bounce buffer)

2. memcpy the skb data and then map it (no more zero-copy)

 

Thanks!

Roy

 

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