From: "Michael S. Tsirkin" <mst@redhat.com>
To: David Miller <davem@davemloft.net>
Cc: paulmck@linux.vnet.ibm.com, arnd@arndb.de, linux-kernel@vger.kernel.org
Subject: Re: [PATCH RFC] hlist_add_tail_rcu disable sparse warning
Date: Mon, 5 Dec 2016 05:29:23 +0200 [thread overview]
Message-ID: <20161205052506-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20161125.195223.1182462379062736127.davem@davemloft.net>
On Fri, Nov 25, 2016 at 07:52:23PM -0500, David Miller wrote:
> From: "Michael S. Tsirkin" <mst@redhat.com>
> Date: Wed, 23 Nov 2016 22:48:19 +0200
>
> > I would appreciate review to confirm the function doesn't
> > do anything unsafe though.
> >
> > In particular, should this use __hlist_for_each_rcu instead?
> > I note that __hlist_for_each_rcu does rcu_dereference
> > internally, which is missing here.
>
> I personally think it should use __hlist_for_each_rcu, otherwise
> nothing expresses the rcu-ness of the operation.
What does "rcu-ness" mean in this context?
The question is not just about making the code pretty.
This operation is called outside any rcu critical section.
If you are going to call __hlist_for_each_rcu which
calls rcu_dereference, you should do it inside
a critical section.
Other operations such as hlist_add_behind_rcu manipulate
lists manually, maybe this one should, too?
Paul?
--
MST
next prev parent reply other threads:[~2016-12-05 3:29 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-23 20:48 [PATCH RFC] hlist_add_tail_rcu disable sparse warning Michael S. Tsirkin
2016-11-26 0:52 ` David Miller
2016-11-28 14:39 ` Paul E. McKenney
2016-11-28 15:30 ` Michael S. Tsirkin
2016-12-05 3:47 ` Michael S. Tsirkin
2016-12-05 3:29 ` Michael S. Tsirkin [this message]
2016-12-05 19:37 ` Michael S. Tsirkin
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