swim: add helper for disk cleanup

Disk cleanup can be shared between exit and bringup. Use a
helper to do the work required. The only functional change at
this point is we're being overly paraoid on exit to check for
a null disk as well now, and this should be safe.

We'll later expand on this, this change just makes subsequent
changes easier to read.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/20210927220302.1073499-9-mcgrof@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/block/swim.c

@@ -772,6 +772,17 @@ static const struct blk_mq_ops swim_mq_ops = {
 	.queue_rq = swim_queue_rq,
 };
 
+static void swim_cleanup_floppy_disk(struct floppy_state *fs)
+{
+	struct gendisk *disk = fs->disk;
+
+	if (!disk)
+		return;
+
+	blk_cleanup_disk(disk);
+	blk_mq_free_tag_set(&fs->tag_set);
+}
+
 static int swim_floppy_init(struct swim_priv *swd)
 {
 	int err;
@@ -836,12 +847,7 @@ static int swim_floppy_init(struct swim_priv *swd)
 exit_put_disks:
 	unregister_blkdev(FLOPPY_MAJOR, "fd");
 	do {
-		struct gendisk *disk = swd->unit[drive].disk;
-
-		if (!disk)
-			continue;
-		blk_cleanup_disk(disk);
-		blk_mq_free_tag_set(&swd->unit[drive].tag_set);
+		swim_cleanup_floppy_disk(&swd->unit[drive]);
 	} while (drive--);
 	return err;
 }
@@ -912,8 +918,7 @@ static int swim_remove(struct platform_device *dev)
 
 	for (drive = 0; drive < swd->floppy_count; drive++) {
 		del_gendisk(swd->unit[drive].disk);
-		blk_cleanup_disk(swd->unit[drive].disk);
-		blk_mq_free_tag_set(&swd->unit[drive].tag_set);
+		swim_cleanup_floppy_disk(&swd->unit[drive]);
 	}
 
 	unregister_blkdev(FLOPPY_MAJOR, "fd");