[PATCH net] net: phy: mscc: fix deadlock in vsc85xx_default_config

From: Quentin Schulz
Date: Thu Nov 22 2018 - 08:14:17 EST


The vsc85xx_default_config function called in the vsc85xx_config_init
function which is used by VSC8530, VSC8531, VSC8540 and VSC8541 PHYs
mistakenly calls phy_read and phy_write in-between phy_select_page and
phy_restore_page.

phy_select_page and phy_restore_page actually take and release the MDIO
bus lock so __phy_write and __phy_read (which assume that you already
have the MDIO bus lock unlike phy_write and phy_read) should be used for
any call in between the two said functions.

Let's fix this deadlock.

Fixes: 6a0bfbbe20b0 ("net: phy: mscc: migrate to phy_select/restore_page functions")

Signed-off-by: Quentin Schulz <quentin.schulz@xxxxxxxxxxx>
---
drivers/net/phy/mscc.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/phy/mscc.c b/drivers/net/phy/mscc.c
index 62269e578718..6856fe4d1a60 100644
--- a/drivers/net/phy/mscc.c
+++ b/drivers/net/phy/mscc.c
@@ -814,10 +814,10 @@ static int vsc85xx_default_config(struct phy_device *phydev)
if (rc < 0)
goto out_unlock;

- reg_val = phy_read(phydev, MSCC_PHY_RGMII_CNTL);
+ reg_val = __phy_read(phydev, MSCC_PHY_RGMII_CNTL);
reg_val &= ~(RGMII_RX_CLK_DELAY_MASK);
reg_val |= (RGMII_RX_CLK_DELAY_1_1_NS << RGMII_RX_CLK_DELAY_POS);
- phy_write(phydev, MSCC_PHY_RGMII_CNTL, reg_val);
+ __phy_write(phydev, MSCC_PHY_RGMII_CNTL, reg_val);

out_unlock:
rc = phy_restore_page(phydev, rc, rc > 0 ? 0 : rc);
--
2.17.1