zram: avoid race between zram_remove and disksize_store

mainline inclusion
from mainline-v5.16-rc1
commit 5a4b6536
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I674BF
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=5a4b653655d554b5f51a5d2252882708c56a6f7e



--------------------------------

After resetting device in zram_remove(), disksize_store still may come and
allocate resources again before deleting gendisk, fix the race by resetting
zram after del_gendisk() returns. At that time, disksize_store can't come
any more.

Reported-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Link: https://lore.kernel.org/r/20211025025426.2815424-4-ming.lei@redhat.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

Conflicts:
	drivers/block/zram/zram_drv.c

Signed-off-by: Longlong Xia <xialonglong1@huawei.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>