RDMA/hns: Fix comparison of unsigned long variable 'end' with less than zero

Currently the comparison of end with less than zero is always false
because end is an unsigned long.  Also, replace checks of end with
non-zero with end > 0 as it is possible that the #defined decrement may be
changed in the future causing end to step over zero and go negative.

The initialization of end with 0 is also redundant as this value is never
read and is later set to HW_SYNC_TIMEOUT_MSECS, so fix this by
initializing it with this value to begin with.

Link: https://lore.kernel.org/r/20190531092101.28772-1-colin.king@canonical.com
Addresses-Coverity: ("Unsigned compared against 0")
Fixes: 669cefb6 ("RDMA/hns: Remove jiffies operation in disable interrupt context")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/hns/hns_roce_hem.c

@@ -324,7 +324,7 @@ static int hns_roce_set_hem(struct hns_roce_dev *hr_dev,
 {
 	spinlock_t *lock = &hr_dev->bt_cmd_lock;
 	struct device *dev = hr_dev->dev;
-	unsigned long end = 0;
+	long end;
 	unsigned long flags;
 	struct hns_roce_hem_iter iter;
 	void __iomem *bt_cmd;
@@ -375,7 +375,7 @@ static int hns_roce_set_hem(struct hns_roce_dev *hr_dev,
 		bt_cmd = hr_dev->reg_base + ROCEE_BT_CMD_H_REG;
 
 		end = HW_SYNC_TIMEOUT_MSECS;
-		while (end) {
+		while (end > 0) {
 			if (!(readl(bt_cmd) >> BT_CMD_SYNC_SHIFT))
 				break;
 

drivers/infiniband/hw/hns/hns_roce_hw_v1.c

@@ -969,7 +969,7 @@ static int hns_roce_v1_recreate_lp_qp(struct hns_roce_dev *hr_dev)
 	struct hns_roce_free_mr *free_mr;
 	struct hns_roce_v1_priv *priv;
 	struct completion comp;
-	unsigned long end = HNS_ROCE_V1_RECREATE_LP_QP_TIMEOUT_MSECS;
+	long end = HNS_ROCE_V1_RECREATE_LP_QP_TIMEOUT_MSECS;
 
 	priv = (struct hns_roce_v1_priv *)hr_dev->priv;
 	free_mr = &priv->free_mr;
@@ -989,7 +989,7 @@ static int hns_roce_v1_recreate_lp_qp(struct hns_roce_dev *hr_dev)
 
 	queue_work(free_mr->free_mr_wq, &(lp_qp_work->work));
 
-	while (end) {
+	while (end > 0) {
 		if (try_wait_for_completion(&comp))
 			return 0;
 		msleep(HNS_ROCE_V1_RECREATE_LP_QP_WAIT_VALUE);
@@ -1107,7 +1107,7 @@ static int hns_roce_v1_dereg_mr(struct hns_roce_dev *hr_dev,
 	struct hns_roce_free_mr *free_mr;
 	struct hns_roce_v1_priv *priv;
 	struct completion comp;
-	unsigned long end = HNS_ROCE_V1_FREE_MR_TIMEOUT_MSECS;
+	long end = HNS_ROCE_V1_FREE_MR_TIMEOUT_MSECS;
 	unsigned long start = jiffies;
 	int npages;
 	int ret = 0;
@@ -1137,7 +1137,7 @@ static int hns_roce_v1_dereg_mr(struct hns_roce_dev *hr_dev,
 
 	queue_work(free_mr->free_mr_wq, &(mr_work->work));
 
-	while (end) {
+	while (end > 0) {
 		if (try_wait_for_completion(&comp))
 			goto free_mr;
 		msleep(HNS_ROCE_V1_FREE_MR_WAIT_VALUE);
@@ -2428,7 +2428,8 @@ static int hns_roce_v1_clear_hem(struct hns_roce_dev *hr_dev,
 {
 	struct device *dev = &hr_dev->pdev->dev;
 	struct hns_roce_v1_priv *priv;
-	unsigned long end = 0, flags = 0;
+	unsigned long flags = 0;
+	long end = HW_SYNC_TIMEOUT_MSECS;
 	__le32 bt_cmd_val[2] = {0};
 	void __iomem *bt_cmd;
 	u64 bt_ba = 0;
@@ -2466,7 +2467,6 @@ static int hns_roce_v1_clear_hem(struct hns_roce_dev *hr_dev,
 
 	bt_cmd = hr_dev->reg_base + ROCEE_BT_CMD_H_REG;
 
-	end = HW_SYNC_TIMEOUT_MSECS;
 	while (1) {
 		if (readl(bt_cmd) >> BT_CMD_SYNC_SHIFT) {
 			if (!end) {