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From: John Baldwin <jhb@freebsd.org>
To: Andrey Chernov <ache@freebsd.org>
Date: Thu, 26 Jan 2012 08:39:07 -0500
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Cc: svn-src-head@freebsd.org, David Schultz <das@freebsd.org>,
	src-committers@freebsd.org, Mark Murray <markm@freebsd.org>,
	svn-src-all@freebsd.org
Subject: Re: svn commit: r230230 - head/sys/dev/random
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On Wednesday, January 25, 2012 10:39:50 pm Andrey Chernov wrote:
> On Thu, Jan 26, 2012 at 07:03:05AM +0400, Andrey Chernov wrote:
> > On Wed, Jan 25, 2012 at 07:16:41PM +0000, Mark Murray wrote:
> > > I thought you were going to do this as a function? It would be
> > > slightly neater to do it that way.
> > > 
> > > Looks good! Are you sure this needs no locking or volatile
> > > variables?
> > 
> > Now with function, volatile, atomic and even enum:
> 
> Sorry. Reading of state variable should be atomical too. Fixed version:

What is the purpose of the atomics?  Doing atomic_load/atomic_store
is just as racy as if you had not used atomics at all.  Should you be
using atomic_cmpset instead, e.g.:

	case ARC4_ENTER_HAVE:
		/* XXX: What does it mean for this to fail? */
		atomic_cmpset_int(&iniseed_state, ARC4_ENTER_NONE, ARC4_ENTER_HAVE);
		break;


-- 
John Baldwin