net: dsa: qca8k: handle qca8k_set_page errors

With a remote possibility, the set_page function can fail. Since this is
a critical part of the write/read qca8k regs, propagate the error and
terminate any read/write operation.

Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/dsa/qca8k.c b/drivers/net/dsa/qca8k.c
index 3c882d3..c983028 100644 (file)
--- a/drivers/net/dsa/qca8k.c
+++ b/drivers/net/dsa/qca8k.c
@@ -127,16 +127,23 @@ qca8k_mii_write32(struct mii_bus *bus, int phy_id, u32 regnum, u32 val)
                                    "failed to write qca8k 32bit register\n");
 }
 
-static void
+static int
 qca8k_set_page(struct mii_bus *bus, u16 page)
 {
+       int ret;
+
        if (page == qca8k_current_page)
-               return;
+               return 0;
 
-       if (bus->write(bus, 0x18, 0, page) < 0)
+       ret = bus->write(bus, 0x18, 0, page);
+       if (ret < 0) {
                dev_err_ratelimited(&bus->dev,
                                    "failed to set qca8k page\n");
+               return ret;
+       }
+
        qca8k_current_page = page;
+       return 0;
 }
 
 static u32
@@ -150,11 +157,14 @@ qca8k_read(struct qca8k_priv *priv, u32 reg)
 
        mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
 
-       qca8k_set_page(bus, page);
+       val = qca8k_set_page(bus, page);
+       if (val < 0)
+               goto exit;
+
        val = qca8k_mii_read32(bus, 0x10 | r2, r1);
 
+exit:
        mutex_unlock(&bus->mdio_lock);
-
        return val;
 }
 
@@ -163,14 +173,19 @@ qca8k_write(struct qca8k_priv *priv, u32 reg, u32 val)
 {
        struct mii_bus *bus = priv->bus;
        u16 r1, r2, page;
+       int ret;
 
        qca8k_split_addr(reg, &r1, &r2, &page);
 
        mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
 
-       qca8k_set_page(bus, page);
+       ret = qca8k_set_page(bus, page);
+       if (ret < 0)
+               goto exit;
+
        qca8k_mii_write32(bus, 0x10 | r2, r1, val);
 
+exit:
        mutex_unlock(&bus->mdio_lock);
 }
 
@@ -185,12 +200,16 @@ qca8k_rmw(struct qca8k_priv *priv, u32 reg, u32 mask, u32 val)
 
        mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
 
-       qca8k_set_page(bus, page);
+       ret = qca8k_set_page(bus, page);
+       if (ret < 0)
+               goto exit;
+
        ret = qca8k_mii_read32(bus, 0x10 | r2, r1);
        ret &= ~mask;
        ret |= val;
        qca8k_mii_write32(bus, 0x10 | r2, r1, ret);
 
+exit:
        mutex_unlock(&bus->mdio_lock);
 
        return ret;