Re: [PATCH] atm: eni: avoid accessing the data mapped to streaming DMA

[David Miller]

From: Jia-Ju Bai <baiji...@tsinghua.edu.cn>
Date: Sun,  2 Aug 2020 17:16:11 +0800

> In do_tx(), skb->data is mapped to streaming DMA on line 1111:
>   paddr = dma_map_single(...,skb->data,DMA_TO_DEVICE);
> 
> Then skb->data is accessed on line 1153:
>   (skb->data[3] & 0xf)
> 
> This access may cause data inconsistency between CPU cache and hardware.
> 
> To fix this problem, skb->data[3] is assigned to a local variable before
> DMA mapping, and then the driver accesses this local variable instead of
> skb->data[3].
> 
> Signed-off-by: Jia-Ju Bai <baiji...@tsinghua.edu.cn>

Applied.