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authorAurelien Chartier <aurelien.chartier@citrix.com>2013-05-28 18:09:56 +0100
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2013-05-29 09:04:19 -0400
commit2abb274629614bef4044a0b98ada42e977feadfd (patch)
tree0c4ef9f17333b7e6ec558a10cf7d218a52d85276 /drivers
parent1d7004f0593f631b78745e4c835d8e09b31f4996 (diff)
downloadlinux-2abb274629614bef4044a0b98ada42e977feadfd.tar.gz
xenbus: delay xenbus frontend resume if xenstored is not running
If the xenbus frontend is located in a domain running xenstored, the device resume is hanging because it is happening before the process resume. This patch adds extra logic to the resume code to check if we are the domain running xenstored and delay the resume if needed. Signed-off-by: Aurelien Chartier <aurelien.chartier@citrix.com> [Changes in v2: - Instead of bypassing the resume, process it in a workqueue] [Changes in v3: - Add a struct work in xenbus_device to avoid dynamic allocation - Several small code fixes] [Changes in v4: - Use a dedicated workqueue] [Changes in v5: - Move create_workqueue error handling to xenbus_frontend_dev_resume] Acked-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/xen/xenbus/xenbus_probe_frontend.c37
1 files changed, 36 insertions, 1 deletions
diff --git a/drivers/xen/xenbus/xenbus_probe_frontend.c b/drivers/xen/xenbus/xenbus_probe_frontend.c
index 3159a37d966..a7e25073de1 100644
--- a/drivers/xen/xenbus/xenbus_probe_frontend.c
+++ b/drivers/xen/xenbus/xenbus_probe_frontend.c
@@ -29,6 +29,8 @@
#include "xenbus_probe.h"
+static struct workqueue_struct *xenbus_frontend_wq;
+
/* device/<type>/<id> => <type>-<id> */
static int frontend_bus_id(char bus_id[XEN_BUS_ID_SIZE], const char *nodename)
{
@@ -89,9 +91,40 @@ static void backend_changed(struct xenbus_watch *watch,
xenbus_otherend_changed(watch, vec, len, 1);
}
+static void xenbus_frontend_delayed_resume(struct work_struct *w)
+{
+ struct xenbus_device *xdev = container_of(w, struct xenbus_device, work);
+
+ xenbus_dev_resume(&xdev->dev);
+}
+
+static int xenbus_frontend_dev_resume(struct device *dev)
+{
+ /*
+ * If xenstored is running in this domain, we cannot access the backend
+ * state at the moment, so we need to defer xenbus_dev_resume
+ */
+ if (xen_store_domain_type == XS_LOCAL) {
+ struct xenbus_device *xdev = to_xenbus_device(dev);
+
+ if (!xenbus_frontend_wq) {
+ pr_err("%s: no workqueue to process delayed resume\n",
+ xdev->nodename);
+ return -EFAULT;
+ }
+
+ INIT_WORK(&xdev->work, xenbus_frontend_delayed_resume);
+ queue_work(xenbus_frontend_wq, &xdev->work);
+
+ return 0;
+ }
+
+ return xenbus_dev_resume(dev);
+}
+
static const struct dev_pm_ops xenbus_pm_ops = {
.suspend = xenbus_dev_suspend,
- .resume = xenbus_dev_resume,
+ .resume = xenbus_frontend_dev_resume,
.freeze = xenbus_dev_suspend,
.thaw = xenbus_dev_cancel,
.restore = xenbus_dev_resume,
@@ -440,6 +473,8 @@ static int __init xenbus_probe_frontend_init(void)
register_xenstore_notifier(&xenstore_notifier);
+ xenbus_frontend_wq = create_workqueue("xenbus_frontend");
+
return 0;
}
subsys_initcall(xenbus_probe_frontend_init);