net: hisilicon: Fix usage of uninitialized variable in function mdio_sc_cfg_reg_write()

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>

diff --git a/drivers/net/ethernet/hisilicon/hns_mdio.c b/drivers/net/ethernet/hisilicon/hns_mdio.c
index 3e863a71c513678342017fc4f5636edd80e7de0e..7df5d7d211d47533055f17e9d50a2384cfd5e28f 100644 (file)
--- 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 hns_mdio_device *mdio_dev,
 {
        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;