cciss: Add lunid attribute to each logical drive in /sys

Add lunid attribute to each logical drive at
/sys/devices/<dev>/ccissX/cXdY/lunid for controller X,
logical drive Y
Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

Documentation/ABI/testing/sysfs-bus-pci-devices-cciss

@@ -38,3 +38,10 @@ Kernel Version:	2.6.31
 Contact:	iss_storagedev@hp.com
 Description:	Kicks of a rescan of the controller to discover logical
 		drive topology changes.
+
+Where:		/sys/bus/pci/devices/<dev>/ccissX/cXdY/lunid
+Date:		August 2009
+Kernel Version: 2.6.31
+Contact:	iss_storagedev@hp.com
+Description:	Displays the 8-byte LUN ID used to address logical
+		drive Y of controller X.

drivers/block/cciss.c

@@ -579,6 +579,31 @@ static ssize_t dev_show_rev(struct device *dev,
 }
 DEVICE_ATTR(rev, S_IRUGO, dev_show_rev, NULL);
 
+static ssize_t cciss_show_lunid(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	drive_info_struct *drv = dev_get_drvdata(dev);
+	struct ctlr_info *h = to_hba(drv->dev->parent);
+	unsigned long flags;
+	unsigned char lunid[8];
+
+	spin_lock_irqsave(CCISS_LOCK(h->ctlr), flags);
+	if (h->busy_configuring) {
+		spin_unlock_irqrestore(CCISS_LOCK(h->ctlr), flags);
+		return -EBUSY;
+	}
+	if (!drv->heads) {
+		spin_unlock_irqrestore(CCISS_LOCK(h->ctlr), flags);
+		return -ENOTTY;
+	}
+	memcpy(lunid, drv->LunID, sizeof(lunid));
+	spin_unlock_irqrestore(CCISS_LOCK(h->ctlr), flags);
+	return snprintf(buf, 20, "0x%02x%02x%02x%02x%02x%02x%02x%02x\n",
+		lunid[0], lunid[1], lunid[2], lunid[3],
+		lunid[4], lunid[5], lunid[6], lunid[7]);
+}
+DEVICE_ATTR(lunid, S_IRUGO, cciss_show_lunid, NULL);
+
 static struct attribute *cciss_host_attrs[] = {
 	&dev_attr_rescan.attr,
 	NULL
@@ -604,6 +629,7 @@ static struct attribute *cciss_dev_attrs[] = {
 	&dev_attr_model.attr,
 	&dev_attr_vendor.attr,
 	&dev_attr_rev.attr,
+	&dev_attr_lunid.attr,
 	NULL
 };