From mboxrd@z Thu Jan  1 00:00:00 1970
From: Xiaozhou Liu <liuxiaozhou@bytedance.com>
Subject: Re: [PATCH net] soreuseport: use RCU_INIT_POINTER() when NULLing
Date: Thu, 13 Dec 2018 11:35:32 +0800
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 <116312bb-3891-b387-1fab-99ae7c61c0cb@gmail.com>
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Cc: netdev@vger.kernel.org, "David S. Miller" <davem@davemloft.net>
To: Eric Dumazet <eric.dumazet@gmail.com>
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On Wed, Dec 12, 2018 at 05:08:45AM -0800, Eric Dumazet wrote:

> 
> It is _not_ faster.
> 
> Just different ways to do the exact same thing.
> 
> For some reason you missed this two years old commit :
> 
> 
> commit 3a37f7275cda5ad25c1fe9be8f20c76c60d175fa
> Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> Date:   Sun May 1 18:46:54 2016 -0700
> 
>     rcu: No ordering for rcu_assign_pointer() of NULL
>     
>     This commit does a compile-time check for rcu_assign_pointer() of NULL,
>     and uses WRITE_ONCE() rather than smp_store_release() in that case.
>     
>     Reported-by: Christoph Hellwig <hch@infradead.org>
>     Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

Thanks for pointing this out. I guess the comments in include/linux/rcupdate.h
may need some updating.


Xiaozhou