block: fix regression for dm

hulk inclusion
category: bugfix
bugzilla: 187345, https://gitee.com/openeuler/kernel/issues/I5L5ZG
CVE: NA

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

Commit d7c2ddc8 ("block: fix that part scan is disabled in
device_add_disk()") introduce a regression:

Test procedures:
dmsetup create test --notable
dmsetup remove test

Test result:
dmsetup will stuck forever

Root cause:
before:
1) dmsetup creat
    add_disk_add_disk_no_queue_reg()
     scan partitions
     uevent
2) blk_register_queue -> notable will not call this
3) dmsetup remove
    wait for uevent

after:
1) dmsetup creat
    add_disk_add_disk_no_queue_reg()
2) blk_register_queue() -> notable will not call this
    scan_partitions
    uevent
3) dmsetup remove
    wait for uevent -> impossible for notable

Fix the problem by moving scan_partitions and uevent from
blk_register_queue() to the end of add_disk_add_disk_no_queue_reg().

Fixes: d7c2ddc8 ("block: fix that part scan is disabled in device_add_disk()")
Signed-off-by: NYu Kuai <yukuai3@huawei.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

block/blk-sysfs.c

@@ -821,38 +821,6 @@ struct kobj_type blk_queue_ktype = {
 	.release	= blk_release_queue,
 };
 
-static void disk_scan_partitions(struct gendisk *disk)
-{
-	struct block_device *bdev;
-
-	if (!get_capacity(disk) || !disk_part_scan_enabled(disk))
-		return;
-
-	set_bit(GD_NEED_PART_SCAN, &disk->state);
-	bdev = blkdev_get_by_dev(disk_devt(disk), FMODE_READ, NULL);
-	if (!IS_ERR(bdev))
-		blkdev_put(bdev, FMODE_READ);
-}
-
-static void disk_init_partition(struct gendisk *disk)
-{
-	struct device *ddev = disk_to_dev(disk);
-	struct disk_part_iter piter;
-	struct hd_struct *part;
-
-	disk_scan_partitions(disk);
-
-	/* 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.
@@ -942,22 +910,9 @@ int blk_register_queue(struct gendisk *disk)
 		kobject_uevent(&q->elevator->kobj, KOBJ_ADD);
 	mutex_unlock(&q->sysfs_lock);
 
-
-	/*
-	 * Set the flag at last, so that block devcie can't be opened
-	 * before it's registration is done.
-	 */
-	disk->flags |= GENHD_FL_UP;
 	ret = 0;
 unlock:
 	mutex_unlock(&q->sysfs_dir_lock);
-	/*
-	 * Init partitions after releasing 'sysfs_dir_lock', otherwise lockdep
-	 * will be confused because it will treat 'bd_mutex' from different
-	 * devices as the same lock.
-	 */
-	if (!ret)
-		disk_init_partition(disk);
 
 	return ret;
 }

block/genhd.c

@@ -736,6 +736,38 @@ static void register_disk(struct device *parent, struct gendisk *disk,
 	}
 }
 
+static void disk_scan_partitions(struct gendisk *disk)
+{
+	struct block_device *bdev;
+
+	if (!get_capacity(disk) || !disk_part_scan_enabled(disk))
+		return;
+
+	set_bit(GD_NEED_PART_SCAN, &disk->state);
+	bdev = blkdev_get_by_dev(disk_devt(disk), FMODE_READ, NULL);
+	if (!IS_ERR(bdev))
+		blkdev_put(bdev, FMODE_READ);
+}
+
+static void disk_init_partition(struct gendisk *disk)
+{
+	struct device *ddev = disk_to_dev(disk);
+	struct disk_part_iter piter;
+	struct hd_struct *part;
+
+	disk_scan_partitions(disk);
+
+	/* 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);
+}
+
 /**
  * __device_add_disk - add disk information to kernel list
  * @parent: parent device for the disk
@@ -814,6 +846,13 @@ static void __device_add_disk(struct device *parent, struct gendisk *disk,
 
 	disk_add_events(disk);
 	blk_integrity_add(disk);
+
+	/*
+	 * Set the flag at last, so that block devcie can't be opened
+	 * before it's registration is done.
+	 */
+	disk->flags |= GENHD_FL_UP;
+	disk_init_partition(disk);
 }
 
 void device_add_disk(struct device *parent, struct gendisk *disk,