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Date:   Thu, 6 Jun 2019 10:19:43 -0400 (EDT)
From:   Alan Stern <stern@rowland.harvard.edu>
To:     Andrea Parri <andrea.parri@amarulasolutions.com>
cc:     "Paul E. McKenney" <paulmck@linux.ibm.com>,
        Boqun Feng <boqun.feng@gmail.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Frederic Weisbecker <fweisbec@gmail.com>,
        Fengguang Wu <fengguang.wu@intel.com>, LKP <lkp@01.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Netdev <netdev@vger.kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Luc Maranget <luc.maranget@inria.fr>,
        Jade Alglave <j.alglave@ucl.ac.uk>
Subject: Re: rcu_read_lock lost its compiler barrier
In-Reply-To: <20190606081657.GA4249@andrea>
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On Thu, 6 Jun 2019, Andrea Parri wrote:

> This seems a sensible change to me: looking forward to seeing a patch,
> on top of -rcu/dev, for further review and testing!
> 
> We could also add (to LKMM) the barrier() for rcu_read_{lock,unlock}()
> discussed in this thread (maybe once the RCU code and the informal doc
> will have settled in such direction).

Yes.  Also for SRCU.  That point had not escaped me.

Alan