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Subject: Re: [PATCH] net: vmxnet3: avoid accessing the data mapped to
 streaming DMA
To:     David Miller <davem@davemloft.net>
Cc:     doshir@vmware.com, pv-drivers@vmware.com, kuba@kernel.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20200802131107.15857-1-baijiaju@tsinghua.edu.cn>
 <20200803.155949.39743839019093809.davem@davemloft.net>
From:   Jia-Ju Bai <baijiaju@tsinghua.edu.cn>
Message-ID: <6d4a6167-2480-0091-33a1-6b0cb81e4645@tsinghua.edu.cn>
Date:   Tue, 4 Aug 2020 10:17:26 +0800
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On 2020/8/4 6:59, David Miller wrote:
> From: Jia-Ju Bai <baijiaju@tsinghua.edu.cn>
> 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
>> hardware.
>>
>> To fix this problem, dma_map_single() is called after these accesses.
>>
>> Signed-off-by: Jia-Ju Bai <baijiaju@tsinghua.edu.cn>
> '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