nvme: Fix ctrl use-after-free during sysfs deletion

mainline inclusion
from mainline-v5.7-rc1
commit b780d741
category: bugfix
bugzilla: NA
CVE: NA
Link: https://gitee.com/openeuler/kernel/issues/I1WGZE



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

In case nvme_sysfs_delete() is called by the user before taking the ctrl
reference count, the ctrl may be freed during the creation and cause the
bug. Take the reference as soon as the controller is externally visible,
which is done by cdev_device_add() in nvme_init_ctrl(). Also take the
reference count at the core layer instead of taking it on each transport
separately.

Signed-off-by: Israel Rukshin <israelr@mellanox.com>
Reviewed-by: Max Gurtovoy <maxg@mellanox.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Conflicts:
    drivers/nvme/host/tcp.c
[No code about TCP in current version.]
Reviewed-by: Chao Leng <lengchao@huawei.com>
Reviewed-by: Jike Cheng <chengjike.cheng@huawei.com>
Signed-off-by: Lijie <lijie34@huawei.com>
Reviewed-by: Hou Tao <houtao1@huawei.com>
Acked-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>