net: stmmac: Fix incorrect dereference in interrupt handlers

If 'dev' or 'data' is NULL, the 'priv' variable has an incorrect address
when dereferencing calling netdev_err().

Since we get as 'dev_id' or 'data' what was passed as the 'dev' argument
to request_irq() during interrupt initialization (that is, the net_device
and rx/tx queue pointers initialized at the time of the call) and since
there are usually no checks for the 'dev_id' argument in such handlers
in other drivers, remove these checks from the handlers in stmmac driver.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 8532f61 ("net: stmmac: introduce MSI Interrupt routines for mac, safety, RX & TX")
Signed-off-by: Pavel Sakharov <p.sakharov@ispras.ru>
Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

@@ -6059,11 +6059,6 @@ static irqreturn_t stmmac_mac_interrupt(int irq, void *dev_id)
 	struct net_device *dev = (struct net_device *)dev_id;
 	struct stmmac_priv *priv = netdev_priv(dev);
 
-	if (unlikely(!dev)) {
-		netdev_err(priv->dev, "%s: invalid dev pointer\n", __func__);
-		return IRQ_NONE;
-	}
-
 	/* Check if adapter is up */
 	if (test_bit(STMMAC_DOWN, &priv->state))
 		return IRQ_HANDLED;
@@ -6079,11 +6074,6 @@ static irqreturn_t stmmac_safety_interrupt(int irq, void *dev_id)
 	struct net_device *dev = (struct net_device *)dev_id;
 	struct stmmac_priv *priv = netdev_priv(dev);
 
-	if (unlikely(!dev)) {
-		netdev_err(priv->dev, "%s: invalid dev pointer\n", __func__);
-		return IRQ_NONE;
-	}
-
 	/* Check if adapter is up */
 	if (test_bit(STMMAC_DOWN, &priv->state))
 		return IRQ_HANDLED;
@@ -6105,11 +6095,6 @@ static irqreturn_t stmmac_msi_intr_tx(int irq, void *data)
 	dma_conf = container_of(tx_q, struct stmmac_dma_conf, tx_queue[chan]);
 	priv = container_of(dma_conf, struct stmmac_priv, dma_conf);
 
-	if (unlikely(!data)) {
-		netdev_err(priv->dev, "%s: invalid dev pointer\n", __func__);
-		return IRQ_NONE;
-	}
-
 	/* Check if adapter is up */
 	if (test_bit(STMMAC_DOWN, &priv->state))
 		return IRQ_HANDLED;
@@ -6136,11 +6121,6 @@ static irqreturn_t stmmac_msi_intr_rx(int irq, void *data)
 	dma_conf = container_of(rx_q, struct stmmac_dma_conf, rx_queue[chan]);
 	priv = container_of(dma_conf, struct stmmac_priv, dma_conf);
 
-	if (unlikely(!data)) {
-		netdev_err(priv->dev, "%s: invalid dev pointer\n", __func__);
-		return IRQ_NONE;
-	}
-
 	/* Check if adapter is up */
 	if (test_bit(STMMAC_DOWN, &priv->state))
 		return IRQ_HANDLED;