[PATCH net] net: emac: guard PHY bitmap teardown

[Rosen Penev <rosenp@gmail.com>]

PHY-less and fixed-link configurations retain a negative PHY address.
Avoid shifting by that value while removing the device, and serialize the
bitmap update with PHY discovery.

Fixes: d6f144830bdf ("ibm/emac: fix improper cleanup when device is removed to allow re-bind")
Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
 drivers/net/ethernet/ibm/emac/core.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/ibm/emac/core.c b/drivers/net/ethernet/ibm/emac/core.c
index 4124a90b18c4..0f534af2f3de 100644
--- a/drivers/net/ethernet/ibm/emac/core.c
+++ b/drivers/net/ethernet/ibm/emac/core.c
@@ -3240,8 +3240,11 @@ static void emac_remove(struct platform_device *ofdev)
 	if (emac_has_feature(dev, EMAC_FTR_HAS_ZMII))
 		zmii_detach(dev->zmii_dev, dev->zmii_port);
 
-	busy_phy_map &= ~(1 << dev->phy.address);
+	mutex_lock(&emac_phy_map_lock);
+	if (dev->phy.address >= 0 && dev->phy.address < 32)
+		busy_phy_map &= ~BIT(dev->phy.address);
 	DBG(dev, "busy_phy_map now %#x" NL, busy_phy_map);
+	mutex_unlock(&emac_phy_map_lock);
 
 	mal_unregister_commac(dev->mal, &dev->commac);
 	emac_put_deps(dev);
-- 
2.56.0