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| H A D | idt77252.c | diff cbbb64f62acd97429f517bd382ada9d618c8856a Sun Aug 02 04:33:40 CDT 2020 Jia-Ju Bai <baijiaju@tsinghua.edu.cn> 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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