mainline inclusion
from mainline-v4.20-rc1
commit 4f802170
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I47H3V
CVE: NA

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

commit 4f802170 upstream.
Backport summary: for 4.19 kernel ICX PCIe Gen4 support.

This patch provides DPC save and restore capabilities.  This is necessary
for the driver to observe DPC events in the event the configuration space
needs to be restored after a reset.
Signed-off-by: NKeith Busch <keith.busch@intel.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NSinan Kaya <okaya@kernel.org>
(cherry picked from commit 4f802170)
Signed-off-by: NEthan Zhao <haifeng.zhao@intel.com>
Signed-off-by: NJackie Liu <liuyun01@kylinos.cn>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: NXiongfeng Wang <wangxiongfeng2@huawei.com>
Reviewed-by: NXie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>