From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH] net: fix race in the receive/select
Date: Thu, 25 Jun 2009 19:11:41 -0700 (PDT)
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From: Davide Libenzi <davidel@xmailserver.org>
Date: Thu, 25 Jun 2009 19:04:04 -0700 (PDT)

> On Fri, 26 Jun 2009, Eric Dumazet wrote:
> 
>> Adding a plain smp_mb() in tcp_poll() for example would slowdown select()/poll() with NULL
>> timeout.
> 
> Do you think of it as good design adding an MB on a subsystem, because of 
> the special locking logic of another one?
> The (eventual) slowdown, IMO can be argued sideways, by saying that 
> non-socket users will pay the price for their polls.

Perhaps every performance argument is moot since spin_unlock() used to
have the barrier :-)