Re: [Xen-devel] [PATCH] Convert shutdown to use xenstore

[Anthony Liguori <aliguori@xxxxxxxxxx>]

Rusty Russell wrote:

> /* Only required if your code runs in dom0 as well as domU */
> static int register_xenstore_notifier(struct notifier_block *notifier)
> {
>         int ret = 0;
>
>         down(&xenbus_lock);
>         if (xen_start_info.evtchn)
>                 ret = notifier.notifier_call(notifier, 0, NULL);
>         else
>                 notifier_chain_register(&xenstore_chain, nb);
>         up(&xenbus_lock);
>         return ret;
> }
>  
I like this.  It avoids having special case code for dom0 in all the 
drivers.
> Implementation detail: just use the xenbus_lock rather than another
> lock, and make sure you hold it while traversing, not just registering!
>  
I was following kernel/cpu.c:cpu_down().  Definitely makes sense though.

Regards,

Anthony Liguori

> Rusty.
>  

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