netdev - Re: rhashtable: Remove unnecessary wmb for future

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Date:	Wed, 9 Dec 2015 03:52:12 +0100
From:	Thomas Graf <tgraf@...g.ch>
To:	Herbert Xu <herbert@...dor.apana.org.au>
Cc:	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <eric.dumazet@...il.com>,
	Josh Triplett <josh@...htriplett.org>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	netdev@...r.kernel.org
Subject: Re: rhashtable: Remove unnecessary wmb for future_tbl

On 12/08/15 at 05:09pm, Herbert Xu wrote:
> The patch 9497df88ab5567daa001829051c5f87161a81ff0 ("rhashtable:
> Fix reader/rehash race") added a pair of barriers.  In fact the
> wmb is superfluous because every subsequent write to the old or
> new hash table uses rcu_assign_pointer, which itself carriers a
> full barrier prior to the assignment.
> 
> Therefore we may remove the explicit wmb.
> 
> Signed-off-by: Herbert Xu <herbert@...dor.apana.org.au>

The RELEASE which is now in place afterwards act as a wmb as well,
we are well protected ;-)

Acked-by: Thomas Graf <tgraf@...g.ch>
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