IB/ucm: Use stack variable 'devnum' in ib_ucm_add_one

This change is not useful by itself, but sets us up for a future
change that allows us to dynamically allocate device numbers in case
we have more than IB_UCM_MAX_DEVICES in the system.
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/core/ucm.c

@@ -1239,6 +1239,7 @@ static DEVICE_ATTR(ibdev, S_IRUGO, show_ibdev, NULL);
 
 static void ib_ucm_add_one(struct ib_device *device)
 {
+	int devnum;
 	struct ib_ucm_device *ucm_dev;
 
 	if (!device->alloc_ucontext ||
@@ -1251,16 +1252,17 @@ static void ib_ucm_add_one(struct ib_device *device)
 
 	ucm_dev->ib_dev = device;
 
-	ucm_dev->devnum = find_first_zero_bit(dev_map, IB_UCM_MAX_DEVICES);
-	if (ucm_dev->devnum >= IB_UCM_MAX_DEVICES)
+	devnum = find_first_zero_bit(dev_map, IB_UCM_MAX_DEVICES);
+	if (devnum >= IB_UCM_MAX_DEVICES)
 		goto err;
 
-	set_bit(ucm_dev->devnum, dev_map);
+	ucm_dev->devnum = devnum;
+	set_bit(devnum, dev_map);
 
 	cdev_init(&ucm_dev->cdev, &ucm_fops);
 	ucm_dev->cdev.owner = THIS_MODULE;
 	kobject_set_name(&ucm_dev->cdev.kobj, "ucm%d", ucm_dev->devnum);
-	if (cdev_add(&ucm_dev->cdev, IB_UCM_BASE_DEV + ucm_dev->devnum, 1))
+	if (cdev_add(&ucm_dev->cdev, IB_UCM_BASE_DEV + devnum, 1))
 		goto err;
 
 	ucm_dev->dev.class = &cm_class;
@@ -1281,7 +1283,7 @@ err_dev:
 	device_unregister(&ucm_dev->dev);
 err_cdev:
 	cdev_del(&ucm_dev->cdev);
-	clear_bit(ucm_dev->devnum, dev_map);
+	clear_bit(devnum, dev_map);
 err:
 	kfree(ucm_dev);
 	return;