When "-o device" mount option is not specified, scan the device table
and instantiate the devices if there's any in the device table. In this
case, the tag field of each device slot uniquely specifies a device.
Signed-off-by: NJeffle Xu <jefflexu@linux.alibaba.com>
Reviewed-by: NGao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220512055601.106109-1-jefflexu@linux.alibaba.comSigned-off-by: NGao Xiang <hsiangkao@linux.alibaba.com>