block: convert to idr_alloc()

Convert to the much saner new idr interface. Both bsg and genhd
protect idr w/ mutex making preloading unnecessary.

Signed-off-by: Tejun Heo <[e-mail]>
Acked-by: Jens Axboe <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

block/bsg.c

···
 {
 	struct bsg_class_device *bcd;
 	dev_t dev;
-	int ret, minor;
+	int ret;
 	struct device *class_dev = NULL;
 	const char *devname;
 
···
 
 	mutex_lock(&bsg_mutex);
 
-	ret = idr_pre_get(&bsg_minor_idr, GFP_KERNEL);
-	if (!ret) {
-		ret = -ENOMEM;
+	ret = idr_alloc(&bsg_minor_idr, bcd, 0, BSG_MAX_DEVS, GFP_KERNEL);
+	if (ret < 0) {
+		if (ret == -ENOSPC) {
+			printk(KERN_ERR "bsg: too many bsg devices\n");
+			ret = -EINVAL;
+		}
 		goto unlock;
 	}
 
-	ret = idr_get_new(&bsg_minor_idr, bcd, &minor);
-	if (ret < 0)
-		goto unlock;
-
-	if (minor >= BSG_MAX_DEVS) {
-		printk(KERN_ERR "bsg: too many bsg devices\n");
-		ret = -EINVAL;
-		goto remove_idr;
-	}
-
-	bcd->minor = minor;
+	bcd->minor = ret;
 	bcd->queue = q;
 	bcd->parent = get_device(parent);
 	bcd->release = release;
···
 	device_unregister(class_dev);
 put_dev:
 	put_device(parent);
-remove_idr:
-	idr_remove(&bsg_minor_idr, minor);
+	idr_remove(&bsg_minor_idr, bcd->minor);
 unlock:
 	mutex_unlock(&bsg_mutex);
 	return ret;

block/genhd.c

···
 int blk_alloc_devt(struct hd_struct *part, dev_t *devt)
 {
 	struct gendisk *disk = part_to_disk(part);
-	int idx, rc;
+	int idx;
 
 	/* in consecutive minor range? */
 	if (part->partno < disk->minors) {
···
 	}
 
 	/* allocate ext devt */
-	do {
-		if (!idr_pre_get(&ext_devt_idr, GFP_KERNEL))
-			return -ENOMEM;
-		mutex_lock(&ext_devt_mutex);
-		rc = idr_get_new(&ext_devt_idr, part, &idx);
-		if (!rc && idx >= NR_EXT_DEVT) {
-			idr_remove(&ext_devt_idr, idx);
-			rc = -EBUSY;
-		}
-		mutex_unlock(&ext_devt_mutex);
-	} while (rc == -EAGAIN);
-
-	if (rc)
-		return rc;
+	mutex_lock(&ext_devt_mutex);
+	idx = idr_alloc(&ext_devt_idr, part, 0, NR_EXT_DEVT, GFP_KERNEL);
+	mutex_unlock(&ext_devt_mutex);
+	if (idx < 0)
+		return idx == -ENOSPC ? -EBUSY : idx;
 
 	*devt = MKDEV(BLOCK_EXT_MAJOR, blk_mangle_minor(idx));
 	return 0;