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From: Thomas Monjalon <thomas.monjalon@6wind.com>
To: Olivier MATZ <olivier.matz@6wind.com>
Date: Fri, 11 Apr 2014 08:47:01 -0700 (PDT)
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Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] [memnic PATCH] linux: fix race condition
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2014-04-11 11:41, Olivier MATZ:
> On Thursday, April 03, 2014 07:35:50 AM Hiroshi Shimamoto wrote:
> > From: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
> > 
> > Same as PMD, there is a race condition between host and guest
> > in the guest MEMNIC kernel driver.
> > 
> > Guest PMD                 Host
> > Thread-A     Thread-B     vSwitch
> > 
> >    |idx=0       |idx=0       |p[0] st!=2
> >    |cmpxchg     |            |
> >    |p[0] st->1  |            |
> >    |idx=1       |            |
> >    |fill data   |            |
> >    |p[0] st->2  |            |p[0] st==2
> >    |
> >    |            |            |receive data
> >    |            |            |p[0] st->0
> >    |            |
> >    |            |cmpxchg     |
> >    |            |success     |p[1] st!=2
> >    |            |p[0] st->1  |
> >    |            |
> >                   This is BAD
> > 
> > Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
> > ---
> > 
> >  linux/memnic_net.c | 9 +++++++++
> >  1 file changed, 9 insertions(+)
> 
> Reviewed-by: Olivier Matz <olivier.matz@6wind.com>

Applied

Thanks
-- 
Thomas