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Date: Fri, 26 Sep 2014 18:41:58 +0200
From: Christoph Hellwig <hch@lst.de>
To: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: Linux NFS Mailing List <linux-nfs@vger.kernel.org>
Subject: Re: [PATCH] pnfs/blocklayout: serialize GETDEVICEINFO calls
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On Fri, Sep 26, 2014 at 12:21:06PM -0400, Trond Myklebust wrote:
> > Not without getting rid of the rpc_pipefs interface.  That is on my
> > very long term TODO list, but it will require new userspace support.
> 
> Why is that? rpc_pipefs was designed to be message based, so it should
> work quite well in a multi-threaded environment. We certainly don't
> use mutexes around the gssd up/downcall, and the only reason for the
> mutex in idmapd is to deal with the keyring upcall.

Ok, the GSS code dynamically allocates a new message for each upcall
and thus doesn't have the issue.  I'll take a look if I can do this
in the blocklayout driver as well.