From: Yizhuo <yzhai003@ucr.edu>
Date: Tue, 1 Oct 2019 13:24:39 -0700
Subject: net: hisilicon: Fix usage of uninitialized variable in function
 mdio_sc_cfg_reg_write()
Patch-mainline: v5.4-rc2
Git-commit: 53de429f4e88f538f7a8ec2b18be8c0cd9b2c8e1
References: bsc#1154353 bnc#1151927 5.3.8

In function mdio_sc_cfg_reg_write(), variable "reg_value" could be
uninitialized if regmap_read() fails. However, "reg_value" is used
to decide the control flow later in the if statement, which is
potentially unsafe.

Signed-off-by: Yizhuo <yzhai003@ucr.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/hisilicon/hns_mdio.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/hisilicon/hns_mdio.c
+++ b/drivers/net/ethernet/hisilicon/hns_mdio.c
@@ -148,11 +148,15 @@ static int mdio_sc_cfg_reg_write(struct
 {
 	u32 time_cnt;
 	u32 reg_value;
+	int ret;
 
 	regmap_write(mdio_dev->subctrl_vbase, cfg_reg, set_val);
 
 	for (time_cnt = MDIO_TIMEOUT; time_cnt; time_cnt--) {
-		regmap_read(mdio_dev->subctrl_vbase, st_reg, &reg_value);
+		ret = regmap_read(mdio_dev->subctrl_vbase, st_reg, &reg_value);
+		if (ret)
+			return ret;
+
 		reg_value &= st_msk;
 		if ((!!check_st) == (!!reg_value))
 			break;