[S390] dasd: Add sysfs attribute status and generate uevents.

This patch adds a sysfs-attribute 'status' to make the DASD device-status
accessible from user-space. In addition, the DASD driver generates an
uevent(CHANGE) for the ccw-device on each device-status change.
This enables user-space applications (e.g. udev) to do related processing.
Signed-off-by: Horst Hummel <horst.hummel@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/block/dasd.c

@@ -398,6 +398,9 @@ dasd_change_state(struct dasd_device *device)
 
 	if (device->state == device->target)
 		wake_up(&dasd_init_waitq);
+
+	/* let user-space know that the device status changed */
+	kobject_uevent(&device->cdev->dev.kobj, KOBJ_CHANGE);
 }
 
 /*

drivers/s390/block/dasd_devmap.c

@@ -828,6 +828,46 @@ dasd_discipline_show(struct device *dev, struct device_attribute *attr,
 
 static DEVICE_ATTR(discipline, 0444, dasd_discipline_show, NULL);
 
+static ssize_t
+dasd_device_status_show(struct device *dev, struct device_attribute *attr,
+		     char *buf)
+{
+	struct dasd_device *device;
+	ssize_t len;
+
+	device = dasd_device_from_cdev(to_ccwdev(dev));
+	if (!IS_ERR(device)) {
+		switch (device->state) {
+		case DASD_STATE_NEW:
+			len = snprintf(buf, PAGE_SIZE, "new\n");
+			break;
+		case DASD_STATE_KNOWN:
+			len = snprintf(buf, PAGE_SIZE, "detected\n");
+			break;
+		case DASD_STATE_BASIC:
+			len = snprintf(buf, PAGE_SIZE, "basic\n");
+			break;
+		case DASD_STATE_UNFMT:
+			len = snprintf(buf, PAGE_SIZE, "unformatted\n");
+			break;
+		case DASD_STATE_READY:
+			len = snprintf(buf, PAGE_SIZE, "ready\n");
+			break;
+		case DASD_STATE_ONLINE:
+			len = snprintf(buf, PAGE_SIZE, "online\n");
+			break;
+		default:
+			len = snprintf(buf, PAGE_SIZE, "no stat\n");
+			break;
+		}
+		dasd_put_device(device);
+	} else
+		len = snprintf(buf, PAGE_SIZE, "unknown\n");
+	return len;
+}
+
+static DEVICE_ATTR(status, 0444, dasd_device_status_show, NULL);
+
 static ssize_t
 dasd_alias_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
@@ -939,6 +979,7 @@ static DEVICE_ATTR(eer_enabled, 0644, dasd_eer_show, dasd_eer_store);
 static struct attribute * dasd_attrs[] = {
 	&dev_attr_readonly.attr,
 	&dev_attr_discipline.attr,
+	&dev_attr_status.attr,
 	&dev_attr_alias.attr,
 	&dev_attr_vendor.attr,
 	&dev_attr_uid.attr,