!497 SAS-related bugfix

Merge Pull Request from: @xia-bing1 
 
1. In the NCQ scenario, if multiple I/Os are delivered and one of the I/Os is faulty, a group of slow disks will always occur.
2. During I/O running, a null pointer exception occurs during the pressure test when a disk is removed.
3. When the length of the DMA Setup frame returned by the disk is abnormal, a group of slow disks are triggered. 
 
Link:https://gitee.com/openeuler/kernel/pulls/497

 

Reviewed-by: Jialin Zhang <zhangjialin11@huawei.com>
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>