[PATCH -next RFC 2/3] block: factor out the setting of GD_NEED_PART_SCAN

[Yu Kuai]

From: Yu Kuai <yukuai3@xxxxxxxxxx>

In order to prevent scan partition for a device that is opened
exclusively by someone else, new conditions will be added to
disk_scan_partitions() in the next patch. Hence if device is opened
exclusively between bdev_add() and disk_scan_partitions(), the first
partition scan will fail unexpected. This patch factor out the setting
of GD_NEED_PART_SCAN to prevent the problem.

Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
---
 block/genhd.c | 2 +-
 block/ioctl.c | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/block/genhd.c b/block/genhd.c
index 075d8da284f5..c0d1220bd798 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -367,7 +367,6 @@ int disk_scan_partitions(struct gendisk *disk, fmode_t mode)
 	if (disk->open_partitions)
 		return -EBUSY;
 
-	set_bit(GD_NEED_PART_SCAN, &disk->state);
 	bdev = blkdev_get_by_dev(disk_devt(disk), mode, NULL);
 	if (IS_ERR(bdev))
 		return PTR_ERR(bdev);
@@ -493,6 +492,7 @@ int __must_check device_add_disk(struct device *parent, struct gendisk *disk,
 		if (ret)
 			goto out_unregister_bdi;
 
+		set_bit(GD_NEED_PART_SCAN, &disk->state);
 		bdev_add(disk->part0, ddev->devt);
 		if (get_capacity(disk))
 			disk_scan_partitions(disk, FMODE_READ);
diff --git a/block/ioctl.c b/block/ioctl.c
index 6dd49d877584..0eefcdb936a0 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -528,6 +528,7 @@ static int blkdev_common_ioctl(struct block_device *bdev, fmode_t mode,
 			return -EACCES;
 		if (bdev_is_partition(bdev))
 			return -EINVAL;
+		set_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
 		return disk_scan_partitions(bdev->bd_disk, mode & ~FMODE_EXCL);
 	case BLKTRACESTART:
 	case BLKTRACESTOP:
-- 
2.31.1