---

yaml --- r: 311993 b: refs/heads/master c: b93984c h: refs/heads/master i: 311991: a3f5b2b v: v3
git-mirror · Jul 9, 2012 · d5a500a · d5a500a
1 parent bf5a998
commit d5a500a
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Showing 2 changed files with 9 additions and 3 deletions.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: d4e41649434cd6db2e69783130cba81886dac97f
+refs/heads/master: b93984c9afacd4fe32b785d52a93660d91202b10
diff --git a/trunk/drivers/net/phy/mdio-mux.c b/trunk/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;