Re: [PATCH] IPMI: fix some RCU problems

From: Christoph Hellwig
Date: Thu Dec 28 2006 - 13:31:25 EST


> + if (list_empty(&intf->cmd_rcvrs))
> + INIT_LIST_HEAD(&list);
> + else {
> + list.next = intf->cmd_rcvrs.next;
> + list.prev = intf->cmd_rcvrs.prev;
> + INIT_LIST_HEAD(&intf->cmd_rcvrs);
> +
> + /*
> + * At this point the list body still points to
> + * intf->cmd_rcvrs. Wait for any readers to finish
> + * using the list before we switch the list body over
> + * to the new list.
> + */
> + synchronize_rcu();
> +
> + /* Ready the list for use. */
> + list.next->prev = &list;
> + list.prev->next = &list;
> + }

This kind of thing must not be opencoded in drivers. Please add
a new list_splice_rcu helper to list.h

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