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From: David Howells <dhowells@redhat.com>
To: paulmck@linux.vnet.ibm.com
Cc: dhowells@redhat.com, linux-kernel@vger.kernel.org, mingo@elte.hu,
	laijs@cn.fujitsu.com, dipankar@in.ibm.com,
	akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca,
	josh@joshtriplett.org, dvhltc@us.ibm.com, niv@us.ibm.com,
	tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org,
	Valdis.Kletnieks@vt.edu, eric.dumazet@gmail.com
Subject: Re: [PATCH tip/urgent] rcu: add rcu_access_pointer and rcu_dereference_protected
Date: Wed, 07 Apr 2010 18:00:27 +0100	[thread overview]
Message-ID: <27310.1270659627@redhat.com> (raw)
In-Reply-To: <20100407162620.GA11543@linux.vnet.ibm.com>

Paul E. McKenney <paulmck@linux.vnet.ibm.com> wrote:

> The new rcu_access_pointer() primitive is for the case where the pointer
> is be fetch and not dereferenced.  This primitive may be used without
> protection, RCU or otherwise, due to the fact that it uses ACCESS_ONCE().
> ...
> +#define rcu_access_pointer(p, c) \

NAK.  This shouldn't have the conditional parameter 'c'.  Given that 'c' (by
analogy to rcu_dereference_check()) is there to describe the conditions under
which it's permitted to dereference the pointer, why is that relevant here?
What is it you're proving?

David

  parent reply	other threads:[~2010-04-07 17:01 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-04-07 16:26 [PATCH tip/urgent] rcu: add rcu_access_pointer and rcu_dereference_protected Paul E. McKenney
2010-04-07 16:38 ` Eric Dumazet
2010-04-07 16:45 ` Mathieu Desnoyers
2010-04-07 17:00 ` David Howells [this message]
2010-04-07 17:13   ` Paul E. McKenney
2010-04-07 17:20   ` David Howells
2010-04-07 23:00     ` Paul E. McKenney
2010-04-08 16:46       ` Paul E. McKenney
2010-04-08 19:04       ` David Howells
2010-04-08 19:53         ` Paul E. McKenney

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