atm: idt77252: avoid accessing the data mapped to streaming DMA
In queue_skb(), skb->data is mapped to streaming DMA on line 850: dma_map_single(..., skb->data, ...); Then skb->data is accessed on lines 862 and 863: tbd->word_4 = (skb->data[0] << 24) | (skb->data[1] << 16) | (skb->data[2] << 8) | (skb->data[3] << 0); and on lines 893 and 894: tbd->word_4 = (skb->data[0] << 24) | (skb->data[1] << 16) | (skb->data[2] << 8) | (skb->data[3] << 0); These accesses may cause data inconsistency between CPU cache and hardware. To fix this problem, the calculation result of skb->data is stored in a local variable before DMA mapping, and then the driver accesses this local variable instead of skb->data. Signed-off-by: Jia-Ju Bai <baijiaju@tsinghua.edu.cn> Signed-off-by: David S. Miller <davem@davemloft.net>
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