amiflop: add error handling support for add_disk()

We never checked for errors on add_disk() as this function
returned void. Now that this is fixed, use the shiny new
error handling. The caller for fd_alloc_disk() deals with
the rest of the cleanup like the tag.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/20210927220302.1073499-7-mcgrof@kernel.orgSigned-off-by: Jens Axboe <axboe@kernel.dk>

drivers/block/amiflop.c

@@ -1780,6 +1780,7 @@ static const struct blk_mq_ops amiflop_mq_ops = {
 static int fd_alloc_disk(int drive, int system)
 {
 	struct gendisk *disk;
+	int err;
 
 	disk = blk_mq_alloc_disk(&unit[drive].tag_set, NULL);
 	if (IS_ERR(disk))
@@ -1798,8 +1799,10 @@ static int fd_alloc_disk(int drive, int system)
 	set_capacity(disk, 880 * 2);
 
 	unit[drive].gendisk[system] = disk;
-	add_disk(disk);
-	return 0;
+	err = add_disk(disk);
+	if (err)
+		blk_cleanup_disk(disk);
+	return err;
 }
 
 static int fd_alloc_drive(int drive)