From: David Miller <davem@davemloft.net>
To: thomas.lendacky@amd.com
Cc: netdev@vger.kernel.org, alexander.duyck@gmail.com
Subject: Re: [PATCH net] amd-xgbe: Fix race between access of desc and desc index
Date: Tue, 27 Oct 2015 19:50:07 -0700 (PDT) [thread overview]
Message-ID: <20151027.195007.1435133435434786670.davem@davemloft.net> (raw)
In-Reply-To: <20151026221354.927.9237.stgit@tlendack-t1.amdoffice.net>
From: Tom Lendacky <thomas.lendacky@amd.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@gmail.com>
> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Applied, thanks.
next prev parent reply other threads:[~2015-10-28 2:33 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-26 22:13 [PATCH net] amd-xgbe: Fix race between access of desc and desc index Tom Lendacky
2015-10-28 2:50 ` David Miller [this message]
2015-10-28 13:48 ` Tom Lendacky
2015-11-01 17:04 ` David Miller
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