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-rw-r--r--drivers/xen/xenbus/xenbus_comms.c4
-rw-r--r--drivers/xen/xenbus/xenbus_probe_frontend.c121
2 files changed, 124 insertions, 1 deletions
diff --git a/drivers/xen/xenbus/xenbus_comms.c b/drivers/xen/xenbus/xenbus_comms.c
index 090c61ee8fd..2eff7a6aaa2 100644
--- a/drivers/xen/xenbus/xenbus_comms.c
+++ b/drivers/xen/xenbus/xenbus_comms.c
@@ -212,7 +212,9 @@ int xb_init_comms(void)
printk(KERN_WARNING "XENBUS response ring is not quiescent "
"(%08x:%08x): fixing up\n",
intf->rsp_cons, intf->rsp_prod);
- intf->rsp_cons = intf->rsp_prod;
+ /* breaks kdump */
+ if (!reset_devices)
+ intf->rsp_cons = intf->rsp_prod;
}
if (xenbus_irq) {
diff --git a/drivers/xen/xenbus/xenbus_probe_frontend.c b/drivers/xen/xenbus/xenbus_probe_frontend.c
index b6a2690c9d4..b521ce43d32 100644
--- a/drivers/xen/xenbus/xenbus_probe_frontend.c
+++ b/drivers/xen/xenbus/xenbus_probe_frontend.c
@@ -252,10 +252,131 @@ int __xenbus_register_frontend(struct xenbus_driver *drv,
}
EXPORT_SYMBOL_GPL(__xenbus_register_frontend);
+static DECLARE_WAIT_QUEUE_HEAD(backend_state_wq);
+static int backend_state;
+
+static void xenbus_reset_backend_state_changed(struct xenbus_watch *w,
+ const char **v, unsigned int l)
+{
+ xenbus_scanf(XBT_NIL, v[XS_WATCH_PATH], "", "%i", &backend_state);
+ printk(KERN_DEBUG "XENBUS: backend %s %s\n",
+ v[XS_WATCH_PATH], xenbus_strstate(backend_state));
+ wake_up(&backend_state_wq);
+}
+
+static void xenbus_reset_wait_for_backend(char *be, int expected)
+{
+ long timeout;
+ timeout = wait_event_interruptible_timeout(backend_state_wq,
+ backend_state == expected, 5 * HZ);
+ if (timeout <= 0)
+ printk(KERN_INFO "XENBUS: backend %s timed out.\n", be);
+}
+
+/*
+ * Reset frontend if it is in Connected or Closed state.
+ * Wait for backend to catch up.
+ * State Connected happens during kdump, Closed after kexec.
+ */
+static void xenbus_reset_frontend(char *fe, char *be, int be_state)
+{
+ struct xenbus_watch be_watch;
+
+ printk(KERN_DEBUG "XENBUS: backend %s %s\n",
+ be, xenbus_strstate(be_state));
+
+ memset(&be_watch, 0, sizeof(be_watch));
+ be_watch.node = kasprintf(GFP_NOIO | __GFP_HIGH, "%s/state", be);
+ if (!be_watch.node)
+ return;
+
+ be_watch.callback = xenbus_reset_backend_state_changed;
+ backend_state = XenbusStateUnknown;
+
+ printk(KERN_INFO "XENBUS: triggering reconnect on %s\n", be);
+ register_xenbus_watch(&be_watch);
+
+ /* fall through to forward backend to state XenbusStateInitialising */
+ switch (be_state) {
+ case XenbusStateConnected:
+ xenbus_printf(XBT_NIL, fe, "state", "%d", XenbusStateClosing);
+ xenbus_reset_wait_for_backend(be, XenbusStateClosing);
+
+ case XenbusStateClosing:
+ xenbus_printf(XBT_NIL, fe, "state", "%d", XenbusStateClosed);
+ xenbus_reset_wait_for_backend(be, XenbusStateClosed);
+
+ case XenbusStateClosed:
+ xenbus_printf(XBT_NIL, fe, "state", "%d", XenbusStateInitialising);
+ xenbus_reset_wait_for_backend(be, XenbusStateInitWait);
+ }
+
+ unregister_xenbus_watch(&be_watch);
+ printk(KERN_INFO "XENBUS: reconnect done on %s\n", be);
+ kfree(be_watch.node);
+}
+
+static void xenbus_check_frontend(char *class, char *dev)
+{
+ int be_state, fe_state, err;
+ char *backend, *frontend;
+
+ frontend = kasprintf(GFP_NOIO | __GFP_HIGH, "device/%s/%s", class, dev);
+ if (!frontend)
+ return;
+
+ err = xenbus_scanf(XBT_NIL, frontend, "state", "%i", &fe_state);
+ if (err != 1)
+ goto out;
+
+ switch (fe_state) {
+ case XenbusStateConnected:
+ case XenbusStateClosed:
+ printk(KERN_DEBUG "XENBUS: frontend %s %s\n",
+ frontend, xenbus_strstate(fe_state));
+ backend = xenbus_read(XBT_NIL, frontend, "backend", NULL);
+ if (!backend || IS_ERR(backend))
+ goto out;
+ err = xenbus_scanf(XBT_NIL, backend, "state", "%i", &be_state);
+ if (err == 1)
+ xenbus_reset_frontend(frontend, backend, be_state);
+ kfree(backend);
+ break;
+ default:
+ break;
+ }
+out:
+ kfree(frontend);
+}
+
+static void xenbus_reset_state(void)
+{
+ char **devclass, **dev;
+ int devclass_n, dev_n;
+ int i, j;
+
+ devclass = xenbus_directory(XBT_NIL, "device", "", &devclass_n);
+ if (IS_ERR(devclass))
+ return;
+
+ for (i = 0; i < devclass_n; i++) {
+ dev = xenbus_directory(XBT_NIL, "device", devclass[i], &dev_n);
+ if (IS_ERR(dev))
+ continue;
+ for (j = 0; j < dev_n; j++)
+ xenbus_check_frontend(devclass[i], dev[j]);
+ kfree(dev);
+ }
+ kfree(devclass);
+}
+
static int frontend_probe_and_watch(struct notifier_block *notifier,
unsigned long event,
void *data)
{
+ /* reset devices in Connected or Closed state */
+ if (xen_hvm_domain())
+ xenbus_reset_state();
/* Enumerate devices in xenstore and watch for changes. */
xenbus_probe_devices(&xenbus_frontend);
register_xenbus_watch(&fe_watch);