block: return errors from disk_alloc_events

mainline inclusion
from mainline-v5.15-rc1
commit 92e7755e
category: bugfix
bugzilla: 188733

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=92e7755ebc69233e25a2d1b760aeff536dc4016b



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Prepare for proper error handling in add_disk.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
[hch: split from a larger patch]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20210818144542.19305-9-hch@lst.de


Signed-off-by: Jens Axboe <axboe@kernel.dk>
conflict:
  block/genhd.c
Signed-off-by: Zhong Jinghua <zhongjinghua@huawei.com>
Signed-off-by: Li Nan <linan122@huawei.com>