netdev - Re: [PATCH 2/5] dccp: Auto-load (when supported) CCID plugins for negotiation

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Message-ID: <20081218055617.GC6298@gerrit.erg.abdn.ac.uk>
Date:	Thu, 18 Dec 2008 06:56:17 +0100
From:	Gerrit Renker <gerrit@....abdn.ac.uk>
To:	Micha? Miros?aw <mirqus@...il.com>
Cc:	davem@...emloft.net, dccp@...r.kernel.org, netdev@...r.kernel.org
Subject: Re: [PATCH 2/5] dccp: Auto-load (when supported) CCID plugins for
	negotiation

| > Hence your suggestion does not improve the code. I maintain that it is
| > correct. And it has proven to work in the test tree for more than one
| > year, including tests with up to 100 parallel (iperf) connections.
| 
| The read-lock is just a memory barrier here (not a read memory barrier
| as I wrote
| before) and it's not needed here. If I read the code correctly you are
| testing a single
| pointer to be NULL and don't really care about ordering wrt module
| initialization.
| 
| You can actually annotate ccids[] as read_mostly (it's changed only on module
| load/unload) and protect it with RCU instead of the home-grown rwlock
| you are using.
| 
Hm the details are not so important here. What is important is that your
observation and questioning whether the code makes sense has lead to 
finding a deeper problem. Without your posting that may not have
happened. So many thanks indeed, if you have any more observations,
please keep them coming.
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