RDMa/hns: Don't stuck in endless timeout loop

The "end" variable is declared as unsigned and can't be negative, it
leads to the situation where timeout limit is not honored, so let's
convert logic to ensure that loop is bounded.

drivers/infiniband/hw/hns/hns_roce_hw_v1.c: In function _hns_roce_v1_clear_hem_:
drivers/infiniband/hw/hns/hns_roce_hw_v1.c:2471:12: warning: comparison of unsigned expression < 0 is always false [-Wtype-limits]
 2471 |    if (end < 0) {
      |            ^

Fixes: 669cefb6 ("RDMA/hns: Remove jiffies operation in disable interrupt context")
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/hw/hns/hns_roce_hem.h

@@ -34,8 +34,8 @@
 #ifndef _HNS_ROCE_HEM_H
 #define _HNS_ROCE_HEM_H
 
-#define HW_SYNC_TIMEOUT_MSECS		500
 #define HW_SYNC_SLEEP_TIME_INTERVAL	20
+#define HW_SYNC_TIMEOUT_MSECS           (25 * HW_SYNC_SLEEP_TIME_INTERVAL)
 #define BT_CMD_SYNC_SHIFT		31
 
 enum {

drivers/infiniband/hw/hns/hns_roce_hw_v1.c

@@ -2467,7 +2467,7 @@ static int hns_roce_v1_clear_hem(struct hns_roce_dev *hr_dev,
 	end = HW_SYNC_TIMEOUT_MSECS;
 	while (1) {
 		if (readl(bt_cmd) >> BT_CMD_SYNC_SHIFT) {
-			if (end < 0) {
+			if (!end) {
 				dev_err(dev, "Write bt_cmd err,hw_sync is not zero.\n");
 				spin_unlock_irqrestore(&hr_dev->bt_cmd_lock,
 					flags);