ANDROID: dm-bow: Fix 5.15 compatibility issue

Patch

https://patchwork.kernel.org/project/linux-block/patch/20210804094147.459763-8-hch@lst.de/

delays registering the gendisk, so move creating our sysfs nodes until
resume.

Test: runs
Bug: 210958368
Change-Id: If671893d50434bb39ea37babb0bea05cebae6f54
Signed-off-by: Paul Lawrence <paullawrence@google.com>

Author: PaulLawrenceGoogle

drivers/md/dm-bow.c

@@ -694,7 +694,6 @@ static int dm_bow_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	struct bow_context *bc;
 	struct bow_range *br;
 	int ret;
-	struct mapped_device *md = dm_table_get_md(ti->table);
 
 	if (argc < 1) {
 		ti->error = "Invalid argument count";
@@ -735,14 +734,6 @@ static int dm_bow_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	}
 
 	init_completion(&bc->kobj_holder.completion);
-	ret = kobject_init_and_add(&bc->kobj_holder.kobj, &bow_ktype,
-				   &disk_to_dev(dm_disk(md))->kobj, "%s",
-				   "bow");
-	if (ret) {
-		ti->error = "Cannot create sysfs node";
-		goto bad;
-	}
-
 	mutex_init(&bc->ranges_lock);
 	bc->ranges = RB_ROOT;
 	bc->bufio = dm_bufio_client_create(bc->dev->bdev, bc->block_size, 1, 0,
@@ -799,6 +790,22 @@ static int dm_bow_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	return ret;
 }
 
+void dm_bow_resume(struct dm_target *ti)
+{
+	struct mapped_device *md = dm_table_get_md(ti->table);
+	struct bow_context *bc = ti->private;
+	int ret;
+
+	if (bc->kobj_holder.kobj.state_initialized)
+		return;
+
+	ret = kobject_init_and_add(&bc->kobj_holder.kobj, &bow_ktype,
+				   &disk_to_dev(dm_disk(md))->kobj, "%s",
+				   "bow");
+	if (ret)
+		ti->error = "Cannot create sysfs node";
+}
+
 /****** Handle writes ******/
 
 static int prepare_unchanged_range(struct bow_context *bc, struct bow_range *br,
@@ -1273,6 +1280,7 @@ static struct target_type bow_target = {
 	.features = DM_TARGET_PASSES_CRYPTO,
 	.module = THIS_MODULE,
 	.ctr    = dm_bow_ctr,
+	.resume = dm_bow_resume,
 	.dtr    = dm_bow_dtr,
 	.map    = dm_bow_map,
 	.status = dm_bow_status,