From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Paul E. McKenney" Subject: Re: [PATCH 01/10] netdev: add netdev_continue_rcu Date: Tue, 10 Nov 2009 11:39:45 -0800 Message-ID: <20091110193945.GU8424@linux.vnet.ibm.com> References: <20091110175446.280423729@vyatta.com> <20091110175647.200655064@vyatta.com> Reply-To: paulmck@linux.vnet.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: David Miller , netdev@vger.kernel.org To: Stephen Hemminger Return-path: Received: from e6.ny.us.ibm.com ([32.97.182.146]:40726 "EHLO e6.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754394AbZKJTja (ORCPT ); Tue, 10 Nov 2009 14:39:30 -0500 Received: from d01relay03.pok.ibm.com (d01relay03.pok.ibm.com [9.56.227.235]) by e6.ny.us.ibm.com (8.14.3/8.13.1) with ESMTP id nAAJj6OA031579 for ; Tue, 10 Nov 2009 14:45:06 -0500 Received: from d01av04.pok.ibm.com (d01av04.pok.ibm.com [9.56.224.64]) by d01relay03.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id nAAJdZx1050202 for ; Tue, 10 Nov 2009 14:39:35 -0500 Received: from d01av04.pok.ibm.com (loopback [127.0.0.1]) by d01av04.pok.ibm.com (8.14.3/8.13.1/NCO v10.0 AVout) with ESMTP id nAAJdZKB010650 for ; Tue, 10 Nov 2009 14:39:35 -0500 Content-Disposition: inline In-Reply-To: <20091110175647.200655064@vyatta.com> Sender: netdev-owner@vger.kernel.org List-ID: On Tue, Nov 10, 2009 at 09:54:47AM -0800, Stephen Hemminger wrote: > This adds an RCU macro for continuing search, useful for some > network devices like vlan. Looks good!!! Of course, you need to either have a single RCU read-side critical section cover all the chained list_for_each_entry_continue_rcu() invocations, or you need to do something (e.g., reference count) to make sure that the element in question doesn't disappear in the meantime, right? Thanx, Paul > Signed-off-by: Stephen Hemminger > > --- a/include/linux/netdevice.h 2009-11-09 22:19:08.511480873 -0800 > +++ b/include/linux/netdevice.h 2009-11-10 09:27:17.973376267 -0800 > @@ -1079,6 +1079,8 @@ extern rwlock_t dev_base_lock; /* De > list_for_each_entry_safe(d, n, &(net)->dev_base_head, dev_list) > #define for_each_netdev_continue(net, d) \ > list_for_each_entry_continue(d, &(net)->dev_base_head, dev_list) > +#define for_each_netdev_continue_rcu(net, d) \ > + list_for_each_entry_continue_rcu(d, &(net)->dev_base_head, dev_list) > #define net_device_entry(lh) list_entry(lh, struct net_device, dev_list) > > static inline struct net_device *next_net_device(struct net_device *dev) > --- a/include/linux/rculist.h 2009-11-09 22:19:08.529480859 -0800 > +++ b/include/linux/rculist.h 2009-11-10 09:27:17.974376609 -0800 > @@ -262,6 +262,20 @@ static inline void list_splice_init_rcu( > (pos) = rcu_dereference((pos)->next)) > > /** > + * list_for_each_entry_continue_rcu - continue iteration over list of given type > + * @pos: the type * to use as a loop cursor. > + * @head: the head for your list. > + * @member: the name of the list_struct within the struct. > + * > + * Continue to iterate over list of given type, continuing after > + * the current position. > + */ > +#define list_for_each_entry_continue_rcu(pos, head, member) \ > + for (pos = list_entry_rcu(pos->member.next, typeof(*pos), member); \ > + prefetch(pos->member.next), &pos->member != (head); \ > + pos = list_entry_rcu(pos->member.next, typeof(*pos), member)) > + > +/** > * hlist_del_rcu - deletes entry from hash list without re-initialization > * @n: the element to delete from the hash list. > * > > -- >