Re: [PATCH] net: vmxnet3: avoid accessing the data mapped to streaming DMA

From: Jia-Ju Bai
Date: Mon Aug 03 2020 - 22:17:48 EST

On 2020/8/4 6:59, David Miller wrote:
From: Jia-Ju Bai <baijiaju@xxxxxxxxxxxxxxx>
Date: Sun, 2 Aug 2020 21:11:07 +0800

In vmxnet3_probe_device(), "adapter" is mapped to streaming DMA:
adapter->adapter_pa = dma_map_single(..., adapter, ...);

Then "adapter" is accessed at many places in this function.

Theses accesses may cause data inconsistency between CPU cache and

To fix this problem, dma_map_single() is called after these accesses.

Signed-off-by: Jia-Ju Bai <baijiaju@xxxxxxxxxxxxxxx>
'adapter' is accessed everywhere, in the entire driver, not just here
in the probe function.

Okay, replacing dma_map_single() with dma_alloc_coherent() may be better.
If you think this solution is okay, I can submit a new patch.

Best wishes,
Jia-Ju Bai