xen: export device state to sysfs

joejin00 · Boris Ostrovsky · commit 076e2cedd6ea · 2018-08-28T17:37:40.000-04:00
Export device state to sysfs to allow for easier get device state.

Signed-off-by: Joe Jin &lt;joe.jin@oracle.com&gt;
Reviewed-by: Boris Ostrovsky &lt;boris.ostrovsky@oracle.com&gt;
Cc: Boris Ostrovsky &lt;boris.ostrovsky@oracle.com&gt;
Cc: Juergen Gross &lt;jgross@suse.com&gt;
Cc: Konrad Rzeszutek Wilk &lt;konrad.wilk@oracle.com&gt;
Signed-off-by: Boris Ostrovsky &lt;boris.ostrovsky@oracle.com&gt;
diff --git a/Documentation/ABI/stable/sysfs-bus-xen-backend b/Documentation/ABI/stable/sysfs-bus-xen-backend
@@ -73,3 +73,12 @@ KernelVersion:	3.0
 Contact:	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
 Description:
                 Number of sectors written by the frontend.
+
+What:		/sys/bus/xen-backend/devices/*/state
+Date:		August 2018
+KernelVersion:	4.19
+Contact:	Joe Jin <joe.jin@oracle.com>
+Description:
+                The state of the device. One of: 'Unknown',
+                'Initialising', 'Initialised', 'Connected', 'Closing',
+                'Closed', 'Reconfiguring', 'Reconfigured'.
diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
@@ -402,10 +402,19 @@ static ssize_t modalias_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(modalias);
 
+static ssize_t state_show(struct device *dev,
+			    struct device_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%s\n",
+			xenbus_strstate(to_xenbus_device(dev)->state));
+}
+static DEVICE_ATTR_RO(state);
+
 static struct attribute *xenbus_dev_attrs[] = {
 	&dev_attr_nodename.attr,
 	&dev_attr_devtype.attr,
 	&dev_attr_modalias.attr,
+	&dev_attr_state.attr,
 	NULL,
 };
 
