uio: convert to idr_alloc()

Convert to the much saner new idr interface.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Hans J. Koch" <hjk@hansjkoch.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/uio/uio.c

@@ -369,26 +369,15 @@ static void uio_dev_del_attributes(struct uio_device *idev)
 static int uio_get_minor(struct uio_device *idev)
 {
 	int retval = -ENOMEM;
-	int id;
 
 	mutex_lock(&minor_lock);
-	if (idr_pre_get(&uio_idr, GFP_KERNEL) == 0)
-		goto exit;
-
-	retval = idr_get_new(&uio_idr, idev, &id);
-	if (retval < 0) {
-		if (retval == -EAGAIN)
-			retval = -ENOMEM;
-		goto exit;
-	}
-	if (id < UIO_MAX_DEVICES) {
-		idev->minor = id;
-	} else {
+	retval = idr_alloc(&uio_idr, idev, 0, UIO_MAX_DEVICES, GFP_KERNEL);
+	if (retval >= 0) {
+		idev->minor = retval;
+	} else if (retval == -ENOSPC) {
 		dev_err(idev->dev, "too many uio devices\n");
 		retval = -EINVAL;
-		idr_remove(&uio_idr, id);
 	}
-exit:
 	mutex_unlock(&minor_lock);
 	return retval;
 }