dasd: use bdev_disk_changed instead of blk_drop_partitions

Use the more general interface - the behavior is the same except
that now a change uevent is sent, which is the right thing to do
when the device becomes unusable.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20210406062303.811835-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/partitions/core.c

@@ -544,10 +544,6 @@ int blk_drop_partitions(struct block_device *bdev)
 
 	return 0;
 }
-#ifdef CONFIG_S390
-/* for historic reasons in the DASD driver */
-EXPORT_SYMBOL_GPL(blk_drop_partitions);
-#endif
 
 static bool blk_add_partition(struct gendisk *disk, struct block_device *bdev,
 		struct parsed_partitions *state, int p)

drivers/s390/block/dasd_genhd.c

@@ -146,12 +146,11 @@ void dasd_destroy_partitions(struct dasd_block *block)
 	block->bdev = NULL;
 
 	mutex_lock(&bdev->bd_mutex);
-	blk_drop_partitions(bdev);
+	bdev_disk_changed(bdev, true);
 	mutex_unlock(&bdev->bd_mutex);
 
 	/* Matching blkdev_put to the blkdev_get in dasd_scan_partitions. */
 	blkdev_put(bdev, FMODE_READ);
-	set_capacity(block->gdp, 0);
 }
 
 int dasd_gendisk_init(void)