Re: [Xen-devel] [PATCH 1/3] xen/pv-on-hvm kexec: add xs_introduce to shutdown watches from old kernel

Ian Campbell
2011-08-09T09:15:22Z

> Index: linux-3.0/drivers/xen/xenbus/xenbus_xs.c
> ===================================================================
> --- linux-3.0.orig/drivers/xen/xenbus/xenbus_xs.c
> +++ linux-3.0/drivers/xen/xenbus/xenbus_xs.c
> @@ -620,6 +620,20 @@ static struct xenbus_watch *find_watch(c
> return NULL;
> }
>
> +static int xs_introduce(const char *domid, const char *mfn, const char *port)
> +{
> + struct kvec iov[3];
> +
> + iov[0].iov_base = (char *)domid;
> + iov[0].iov_len = strlen(domid) + 1;
> + iov[1].iov_base = (char *)mfn;
> + iov[1].iov_len = strlen(mfn) + 1;
> + iov[2].iov_base = (char *)port;
> + iov[2].iov_len = strlen(port) + 1;
> +
> + return xs_error(xs_talkv(XBT_NIL, XS_INTRODUCE, iov,
> + ARRAY_SIZE(iov), NULL));

What should we do if this fails?

> +}
> /* Register callback to watch this node. */
> int register_xenbus_watch(struct xenbus_watch *watch)
> {
> @@ -867,10 +881,11 @@ static int xenbus_thread(void *unused)
> return 0;
> }
>
> -int xs_init(void)
> +int xs_init(unsigned long xen_store_mfn)
> {
> int err;
> struct task_struct *task;
> + char domid[12], mfn[24], port[24];
>
> INIT_LIST_HEAD(&xs_state.reply_list);
> spin_lock_init(&xs_state.reply_lock);
> @@ -897,5 +912,15 @@ int xs_init(void)
> if (IS_ERR(task))
> return PTR_ERR(task);
>
> + snprintf(domid, sizeof(domid), "%u", DOMID_SELF);
> + snprintf(mfn, sizeof(mfn), "%lu", xen_store_mfn);
> + snprintf(port, sizeof(port), "%d", xen_store_evtchn);

These can be within the if, or better within the xs_introduce function
itself.

> + if (xen_hvm_domain()) {
> + /* shutdown watches for kexec boot */
> + err = xs_introduce(domid, mfn, port);
> + if (err)
> + printk(KERN_WARNING "xs_introduce failed: %d\n", err);
> + }
> +
> return 0;
> }
>
>
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