RDMA/hns: Fix the double unlock problem of poll_sem

mainline inclusion
from mainline-v5.14-rc5
commit 8b436a99
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4QOTS
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma.git/commit/?id=8b436a99cd708bd158231a0630ffa49b1d6175e4

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

If hns_roce_cmd_use_events() fails then it means that the poll_sem is not
obtained, but the poll_sem is released in hns_roce_cmd_use_polling(), this
will cause an unlock problem.

This is the static checker warning:
	drivers/infiniband/hw/hns/hns_roce_main.c:926 hns_roce_init()
	error: double unlocked '&hr_dev->cmd.poll_sem' (orig line 879)

Event mode and polling mode are mutually exclusive and resources are
separated, so there is no need to process polling mode resources in event
mode.

The initial mode of cmd is polling mode, so even if cmd fails to switch to
event mode, it is not necessary to switch to polling mode.

Fixes: a389d016 ("RDMA/hns: Enable all CMDQ context")
Fixes: 3d50503b ("RDMA/hns: Optimize cmd init and mode selection for hip08")
Link: https://lore.kernel.org/r/1627887374-20019-1-git-send-email-liangwenpeng@huawei.comReported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NYangyang Li <liyangyang20@huawei.com>
Signed-off-by: NWenpeng Liang <liangwenpeng@huawei.com>
Reviewed-by: NLeon Romanovsky <leonro@nvidia.com>
Signed-off-by: NJason Gunthorpe <jgg@nvidia.com>
sigend-off-by: NGuofeng Yue <yueguofeng@hisilicon.com>
Reviewed-by: NYixing Liu <liuyixing1@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/infiniband/hw/hns/hns_roce_cmd.c

@@ -212,8 +212,10 @@ int hns_roce_cmd_use_events(struct hns_roce_dev *hr_dev)
 
 	hr_cmd->context =
 		kcalloc(hr_cmd->max_cmds, sizeof(*hr_cmd->context), GFP_KERNEL);
-	if (!hr_cmd->context)
+	if (!hr_cmd->context) {
+		hr_dev->cmd_mod = 0;
 		return -ENOMEM;
+	}
 
 	for (i = 0; i < hr_cmd->max_cmds; ++i) {
 		hr_cmd->context[i].token = i;
@@ -227,7 +229,6 @@ int hns_roce_cmd_use_events(struct hns_roce_dev *hr_dev)
 	spin_lock_init(&hr_cmd->context_lock);
 
 	hr_cmd->use_events = 1;
-	down(&hr_cmd->poll_sem);
 
 	return 0;
 }
@@ -238,8 +239,6 @@ void hns_roce_cmd_use_polling(struct hns_roce_dev *hr_dev)
 
 	kfree(hr_cmd->context);
 	hr_cmd->use_events = 0;
-
-	up(&hr_cmd->poll_sem);
 }
 
 struct hns_roce_cmd_mailbox *

drivers/infiniband/hw/hns/hns_roce_main.c

@@ -972,11 +972,9 @@ int hns_roce_init(struct hns_roce_dev *hr_dev)
 
 	if (hr_dev->cmd_mod) {
 		ret = hns_roce_cmd_use_events(hr_dev);
-		if (ret) {
+		if (ret)
 			dev_warn(dev,
 				 "Cmd event  mode failed, set back to poll!\n");
-			hns_roce_cmd_use_polling(hr_dev);
-		}
 	}
 
 	ret = hns_roce_init_hem(hr_dev);