netdev - Re: [PATCH net] amd-xgbe: Fix race between access of desc and desc index

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Message-ID: <5630D234.3070600@amd.com>
Date:	Wed, 28 Oct 2015 08:48:36 -0500
From:	Tom Lendacky <thomas.lendacky@....com>
To:	David Miller <davem@...emloft.net>
CC:	<netdev@...r.kernel.org>, <alexander.duyck@...il.com>
Subject: Re: [PATCH net] amd-xgbe: Fix race between access of desc and desc
 index

On 10/27/2015 09:50 PM, David Miller wrote:
> From: Tom Lendacky <thomas.lendacky@....com>
> Date: Mon, 26 Oct 2015 17:13:54 -0500
>
>> During Tx cleanup it's still possible for the descriptor data to be
>> read ahead of the descriptor index. A memory barrier is required between
>> the read of the descriptor index and the start of the Tx cleanup loop.
>> This allows a change to a lighter-weight barrier in the Tx transmit
>> routine just before updating the current descriptor index.
>>
>> Since the memory barrier does result in extra overhead on arm64, keep
>> the previous change to not chase the current descriptor value. This
>> prevents the execution of the barrier for each loop performed.
>>
>> Suggested-by: Alexander Duyck <alexander.duyck@...il.com>
>> Signed-off-by: Tom Lendacky <thomas.lendacky@....com>
>
> Applied, thanks.
>

Thanks David.  Could you queue this up for the 4.1 and 4.2 stable
trees?

Thanks,
Tom
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