net: dsa: mv88e6xxx: Fix counting of ATU violations

The ATU port vector contains a bit per port of the switch. The code
wrongly used it as a port number, and incremented a port counter. This
resulted in the wrong interfaces counter being incremented, and
potentially going off the end of the array of ports.

Fix this by using the source port ID for the violation, which really
is a port number.
Reported-by: Chris Healy <Chris.Healy@zii.aero>
Tested-by: Chris Healy <Chris.Healy@zii.aero>
Fixes: 65f60e45 ("net: dsa: mv88e6xxx: Keep ATU/VTU violation statistics")
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/mv88e6xxx/global1_atu.c

@@ -314,6 +314,7 @@ static irqreturn_t mv88e6xxx_g1_atu_prob_irq_thread_fn(int irq, void *dev_id)
 {
 	struct mv88e6xxx_chip *chip = dev_id;
 	struct mv88e6xxx_atu_entry entry;
+	int spid;
 	int err;
 	u16 val;
 
@@ -336,6 +337,8 @@ static irqreturn_t mv88e6xxx_g1_atu_prob_irq_thread_fn(int irq, void *dev_id)
 	if (err)
 		goto out;
 
+	spid = entry.state;
+
 	if (val & MV88E6XXX_G1_ATU_OP_AGE_OUT_VIOLATION) {
 		dev_err_ratelimited(chip->dev,
 				    "ATU age out violation for %pM\n",
@@ -344,23 +347,23 @@ static irqreturn_t mv88e6xxx_g1_atu_prob_irq_thread_fn(int irq, void *dev_id)
 
 	if (val & MV88E6XXX_G1_ATU_OP_MEMBER_VIOLATION) {
 		dev_err_ratelimited(chip->dev,
-				    "ATU member violation for %pM portvec %x\n",
-				    entry.mac, entry.portvec);
-		chip->ports[entry.portvec].atu_member_violation++;
+				    "ATU member violation for %pM portvec %x spid %d\n",
+				    entry.mac, entry.portvec, spid);
+		chip->ports[spid].atu_member_violation++;
 	}
 
 	if (val & MV88E6XXX_G1_ATU_OP_MISS_VIOLATION) {
 		dev_err_ratelimited(chip->dev,
-				    "ATU miss violation for %pM portvec %x\n",
-				    entry.mac, entry.portvec);
-		chip->ports[entry.portvec].atu_miss_violation++;
+				    "ATU miss violation for %pM portvec %x spid %d\n",
+				    entry.mac, entry.portvec, spid);
+		chip->ports[spid].atu_miss_violation++;
 	}
 
 	if (val & MV88E6XXX_G1_ATU_OP_FULL_VIOLATION) {
 		dev_err_ratelimited(chip->dev,
-				    "ATU full violation for %pM portvec %x\n",
-				    entry.mac, entry.portvec);
-		chip->ports[entry.portvec].atu_full_violation++;
+				    "ATU full violation for %pM portvec %x spid %d\n",
+				    entry.mac, entry.portvec, spid);
+		chip->ports[spid].atu_full_violation++;
 	}
 	mutex_unlock(&chip->reg_lock);