!924 dm: add disk before alloc dax

Merge Pull Request from: @ci-robot 
 
PR sync from:  Li Lingfeng <lilingfeng3@huawei.com>
 https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/thread/KP2DRRZQIPU5IM7FF4GECWSW5466QLFH/ 
 
 
Link:https://gitee.com/openeuler/kernel/pulls/924

 

Reviewed-by: zhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>