block: fix that part scan is disabled in device_add_disk()

hulk inclusion
category: bugfix
bugzilla: 187190, https://gitee.com/src-openeuler/kernel/issues/I5GWOV
CVE: NA

--------------------------------

Commit f20a726b ("block: Fix warning in bd_link_disk_holder()")
moves the setting of flag 'GENHD_FL_UP' behind blkdev_get, which will
disabled part scan:

devcie_add_disk
 register_disk
  blkdev_get
   __blkdev_get
    bdev_get_gendisk
     get_gendisk -> failed because 'GENHD_FL_UP' is not set

And this will cause tests block/017, block/018 and scsi/004 to fail.

Fix the problem by moving part scan as well.

Fixes: f20a726b ("block: Fix warning in bd_link_disk_holder()")
Signed-off-by: NYu Kuai <yukuai3@huawei.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NYongqiang Liu <liuyongqiang13@huawei.com>

block/blk-sysfs.c

@@ -884,6 +884,42 @@ struct kobj_type blk_queue_ktype = {
 	.release	= blk_release_queue,
 };
 
+static void disk_init_partition(struct gendisk *disk)
+{
+	struct device *ddev = disk_to_dev(disk);
+	struct block_device *bdev;
+	struct disk_part_iter piter;
+	struct hd_struct *part;
+
+	/* No minors to use for partitions */
+	if (!disk_part_scan_enabled(disk))
+		goto exit;
+
+	/* No such device (e.g., media were just removed) */
+	if (!get_capacity(disk))
+		goto exit;
+
+	bdev = bdget_disk(disk, 0);
+	if (!bdev)
+		goto exit;
+
+	bdev->bd_invalidated = 1;
+	if (blkdev_get(bdev, FMODE_READ, NULL))
+		goto exit;
+	blkdev_put(bdev, FMODE_READ);
+
+exit:
+	/* announce disk after possible partitions are created */
+	dev_set_uevent_suppress(ddev, 0);
+	kobject_uevent(&ddev->kobj, KOBJ_ADD);
+
+	/* announce possible partitions */
+	disk_part_iter_init(&piter, disk, 0);
+	while ((part = disk_part_iter_next(&piter)))
+		kobject_uevent(&part_to_dev(part)->kobj, KOBJ_ADD);
+	disk_part_iter_exit(&piter);
+}
+
 /**
  * blk_register_queue - register a block layer queue with sysfs
  * @disk: Disk of which the request queue should be registered with sysfs.
@@ -944,6 +980,7 @@ int blk_register_queue(struct gendisk *disk)
 	 * before it's registration is done.
 	 */
 	disk->flags |= GENHD_FL_UP;
+	disk_init_partition(disk);
 	ret = 0;
 unlock:
 	mutex_unlock(&q->sysfs_lock);

block/genhd.c

@@ -598,9 +598,6 @@ static int exact_lock(dev_t devt, void *data)
 static void register_disk(struct device *parent, struct gendisk *disk)
 {
 	struct device *ddev = disk_to_dev(disk);
-	struct block_device *bdev;
-	struct disk_part_iter piter;
-	struct hd_struct *part;
 	int err;
 
 	ddev->parent = parent;
@@ -634,35 +631,6 @@ static void register_disk(struct device *parent, struct gendisk *disk)
 	if (disk->flags & GENHD_FL_HIDDEN)
 		return;
 
-	/* No minors to use for partitions */
-	if (!disk_part_scan_enabled(disk))
-		goto exit;
-
-	/* No such device (e.g., media were just removed) */
-	if (!get_capacity(disk))
-		goto exit;
-
-	bdev = bdget_disk(disk, 0);
-	if (!bdev)
-		goto exit;
-
-	bdev->bd_invalidated = 1;
-	err = blkdev_get(bdev, FMODE_READ, NULL);
-	if (err < 0)
-		goto exit;
-	blkdev_put(bdev, FMODE_READ);
-
-exit:
-	/* announce disk after possible partitions are created */
-	dev_set_uevent_suppress(ddev, 0);
-	kobject_uevent(&ddev->kobj, KOBJ_ADD);
-
-	/* announce possible partitions */
-	disk_part_iter_init(&piter, disk, 0);
-	while ((part = disk_part_iter_next(&piter)))
-		kobject_uevent(&part_to_dev(part)->kobj, KOBJ_ADD);
-	disk_part_iter_exit(&piter);
-
 	if (disk->queue->backing_dev_info->dev) {
 		err = sysfs_create_link(&ddev->kobj,
 			  &disk->queue->backing_dev_info->dev->kobj,