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Message-ID: <AANLkTinsoQMmRWeZBJV4L_G_uL8nurXxBf2v2bNM=Fc4@mail.gmail.com>
Date: Tue, 27 Jul 2010 15:49:51 -0700
From: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
To: Sonny Rao <sonnyrao@...ibm.com>
Cc: netdev@...r.kernel.org, e1000-devel@...ts.sf.net
Subject: Re: [PATCH] Add missing memory barriers to clean_rx_irq functions in
Intel Drivers
On Tue, Jul 27, 2010 at 15:46, Sonny Rao <sonnyrao@...ibm.com> wrote:
> On Tue, Jul 27, 2010 at 03:41:46PM -0700, Jeff Kirsher wrote:
>> On Tue, Jul 27, 2010 at 15:34, Sonny Rao <sonnyrao@...ibm.com> wrote:
>> > This patch is similar to what was fixed in ixgbe in this patch:
>> >
>> > http://marc.info/?l=e1000-devel&m=126593062701537&w=3
>> >
>> > We should add read memory barriers to all the similar cases across the
>> > Intel ethernet driver family. In the case of ixgbevf I've also added
>> > a missing barrier to the clean_tx_irq path because I missed it in my
>> > last patch.
>> >
>> > Without the barrier a processor can speculate a load ahead of the load
>> > which looks at the status bit and get stale information causing a
>> > number of different issues including invalid packet length, NULL
>> > pointers, or bad data since checksumming was assumed to be done
>> > in hardware.
>> >
>> > Signed-off-by: Milton Miller <miltonm@....com>
>> > Signed-off-by: Sonny Rao <sonnyrao@...ibm.com>
>> > cc: stable <stable@...nel.org>
>> >
>>
>> I already have a similar patch in my queue from you Sonny, although I
>> see that this patch has made a few more changes. Is this version 2?
>
> Well, the previous one was for the clean_tx_irq functions this one is
> for the clean_rx_irq functions. I'd gotten the two confused when I
> referenced Anton's original patch -- which was also a clean_rx_irq
> patch. So they are touching different code paths but fixing similar
> problems.
>
>
> --
> Sonny Rao, LTC OzLabs, BML team
> --
Ok, just wanted to make sure. In the first patch (which I already
have in my queue) that cleans up clean_tx_irq, your missing igb driver
as well.
--
Cheers,
Jeff
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