[PATCH v2 4/6] block: move disk unregistration work from del_gendisk() to a helper

[Luis Chamberlain <mcgrof@xxxxxxxxxx>]

There is quite a bit of code on del_gendisk() which relates to
unregistering the disk, using register_disk() as an counter.
Move all this code into a helper instead of re-writing our own,
which we'll need later to handle errors on add_disk().

Since disk unregistrationa also deals with partition unregistration,
provide a halper for that as well, as we'll later need this when
adding error handling for add_disk().

Signed-off-by: Luis Chamberlain <mcgrof@xxxxxxxxxx>
---
 block/genhd.c | 44 ++++++++++++++++++++++++++------------------
 1 file changed, 26 insertions(+), 18 deletions(-)

diff --git a/block/genhd.c b/block/genhd.c
index e5535879d629..b84ba22eed39 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -399,6 +399,25 @@ static void disk_announce(struct gendisk *disk)
 	disk_uevent(disk, KOBJ_ADD);
 }
 
+static void unregister_disk_partitions(struct gendisk *disk)
+{
+	mutex_lock(&disk->open_mutex);
+	disk->flags &= ~GENHD_FL_UP;
+	blk_drop_partitions(disk);
+	mutex_unlock(&disk->open_mutex);
+
+	fsync_bdev(disk->part0);
+	__invalidate_device(disk->part0, true);
+
+	/*
+	 * Unhash the bdev inode for this device so that it can't be looked
+	 * up any more even if openers still hold references to it.
+	 */
+	remove_inode_hash(disk->part0->bd_inode);
+
+	set_capacity(disk, 0);
+}
+
 static void disk_invalidate(struct gendisk *disk)
 {
 	if (!(disk->flags & GENHD_FL_HIDDEN)) {
@@ -424,6 +443,12 @@ static void disk_invalidate(struct gendisk *disk)
 	device_del(disk_to_dev(disk));
 }
 
+static void unregister_disk(struct gendisk *disk)
+{
+	unregister_disk_partitions(disk);
+	disk_invalidate(disk);
+}
+
 static void register_disk(struct device *parent, struct gendisk *disk,
 			  const struct attribute_group **groups)
 {
@@ -614,24 +639,7 @@ void del_gendisk(struct gendisk *disk)
 
 	blk_integrity_del(disk);
 	disk_del_events(disk);
-
-	mutex_lock(&disk->open_mutex);
-	disk->flags &= ~GENHD_FL_UP;
-	blk_drop_partitions(disk);
-	mutex_unlock(&disk->open_mutex);
-
-	fsync_bdev(disk->part0);
-	__invalidate_device(disk->part0, true);
-
-	/*
-	 * Unhash the bdev inode for this device so that it can't be looked
-	 * up any more even if openers still hold references to it.
-	 */
-	remove_inode_hash(disk->part0->bd_inode);
-
-	set_capacity(disk, 0);
-
-	disk_invalidate(disk);
+	unregister_disk(disk);
 }
 EXPORT_SYMBOL(del_gendisk);
 
-- 
2.27.0