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path: root/drivers/net/phy/mdio-mux.c
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Diffstat (limited to 'drivers/net/phy/mdio-mux.c')
-rw-r--r--drivers/net/phy/mdio-mux.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/drivers/net/phy/mdio-mux.c b/drivers/net/phy/mdio-mux.c
index 39ea067..5c12018 100644
--- a/drivers/net/phy/mdio-mux.c
+++ b/drivers/net/phy/mdio-mux.c
@@ -46,7 +46,13 @@ static int mdio_mux_read(struct mii_bus *bus, int phy_id, int regnum)
struct mdio_mux_parent_bus *pb = cb->parent;
int r;
- mutex_lock(&pb->mii_bus->mdio_lock);
+ /* In theory multiple mdio_mux could be stacked, thus creating
+ * more than a single level of nesting. But in practice,
+ * SINGLE_DEPTH_NESTING will cover the vast majority of use
+ * cases. We use it, instead of trying to handle the general
+ * case.
+ */
+ mutex_lock_nested(&pb->mii_bus->mdio_lock, SINGLE_DEPTH_NESTING);
r = pb->switch_fn(pb->current_child, cb->bus_number, pb->switch_data);
if (r)
goto out;
@@ -71,7 +77,7 @@ static int mdio_mux_write(struct mii_bus *bus, int phy_id,
int r;
- mutex_lock(&pb->mii_bus->mdio_lock);
+ mutex_lock_nested(&pb->mii_bus->mdio_lock, SINGLE_DEPTH_NESTING);
r = pb->switch_fn(pb->current_child, cb->bus_number, pb->switch_data);
if (r)
goto out;