zcache: convert to idr_alloc()

idr_get_new*() and friends are about to be deprecated.  Convert to the
new idr_alloc() interface.

Only compile tested.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Dan Magenheimer <dan.magenheimer@oracle.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/staging/zcache/ramster/tcp.c

@@ -300,27 +300,22 @@ static u8 r2net_num_from_nn(struct r2net_node *nn)
 
 static int r2net_prep_nsw(struct r2net_node *nn, struct r2net_status_wait *nsw)
 {
-	int ret = 0;
+	int ret;
 
-	do {
-		if (!idr_pre_get(&nn->nn_status_idr, GFP_ATOMIC)) {
-			ret = -EAGAIN;
-			break;
-		}
-		spin_lock(&nn->nn_lock);
-		ret = idr_get_new(&nn->nn_status_idr, nsw, &nsw->ns_id);
-		if (ret == 0)
-			list_add_tail(&nsw->ns_node_item,
-				      &nn->nn_status_list);
-		spin_unlock(&nn->nn_lock);
-	} while (ret == -EAGAIN);
+	spin_lock(&nn->nn_lock);
+	ret = idr_alloc(&nn->nn_status_idr, nsw, 0, 0, GFP_ATOMIC);
+	if (ret >= 0) {
+		nsw->ns_id = ret;
+		list_add_tail(&nsw->ns_node_item, &nn->nn_status_list);
+	}
+	spin_unlock(&nn->nn_lock);
 
-	if (ret == 0)  {
+	if (ret >= 0) {
 		init_waitqueue_head(&nsw->ns_wq);
 		nsw->ns_sys_status = R2NET_ERR_NONE;
 		nsw->ns_status = 0;
+		return 0;
 	}
-
 	return ret;
 }