2 files changed, 44 insertions, 12 deletions

diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c
index 4e5ae687d2e2..33a4a9a17436 100644
--- a/drivers/net/ethernet/mscc/ocelot.c
+++ b/drivers/net/ethernet/mscc/ocelot.c
@@ -21,11 +21,13 @@ struct ocelot_mact_entry {
 };
 
 static inline u32 ocelot_mact_read_macaccess(struct ocelot *ocelot)
+	__must_hold(&ocelot->mact_lock)
 {
 	return ocelot_read(ocelot, ANA_TABLES_MACACCESS);
 }
 
 static inline int ocelot_mact_wait_for_completion(struct ocelot *ocelot)
+	__must_hold(&ocelot->mact_lock)
 {
 	u32 val;
 
@@ -39,6 +41,7 @@ static inline int ocelot_mact_wait_for_completion(struct ocelot *ocelot)
 static void ocelot_mact_select(struct ocelot *ocelot,
 			       const unsigned char mac[ETH_ALEN],
 			       unsigned int vid)
+	__must_hold(&ocelot->mact_lock)
 {
 	u32 macl = 0, mach = 0;
 
@@ -67,6 +70,7 @@ int ocelot_mact_learn(struct ocelot *ocelot, int port,
 		ANA_TABLES_MACACCESS_ENTRYTYPE(type) |
 		ANA_TABLES_MACACCESS_MAC_TABLE_CMD(MACACCESS_CMD_LEARN);
 	unsigned int mc_ports;
+	int err;
 
 	/* Set MAC_CPU_COPY if the CPU port is used by a multicast entry */
 	if (type == ENTRYTYPE_MACv4)
@@ -79,18 +83,28 @@ int ocelot_mact_learn(struct ocelot *ocelot, int port,
 	if (mc_ports & BIT(ocelot->num_phys_ports))
 		cmd |= ANA_TABLES_MACACCESS_MAC_CPU_COPY;
 
+	mutex_lock(&ocelot->mact_lock);
+
 	ocelot_mact_select(ocelot, mac, vid);
 
 	/* Issue a write command */
 	ocelot_write(ocelot, cmd, ANA_TABLES_MACACCESS);
 
-	return ocelot_mact_wait_for_completion(ocelot);
+	err = ocelot_mact_wait_for_completion(ocelot);
+
+	mutex_unlock(&ocelot->mact_lock);
+
+	return err;
 }
 EXPORT_SYMBOL(ocelot_mact_learn);
 
 int ocelot_mact_forget(struct ocelot *ocelot,
 		       const unsigned char mac[ETH_ALEN], unsigned int vid)
 {
+	int err;
+
+	mutex_lock(&ocelot->mact_lock);
+
 	ocelot_mact_select(ocelot, mac, vid);
 
 	/* Issue a forget command */
@@ -98,7 +112,11 @@ int ocelot_mact_forget(struct ocelot *ocelot,
 		     ANA_TABLES_MACACCESS_MAC_TABLE_CMD(MACACCESS_CMD_FORGET),
 		     ANA_TABLES_MACACCESS);
 
-	return ocelot_mact_wait_for_completion(ocelot);
+	err = ocelot_mact_wait_for_completion(ocelot);
+
+	mutex_unlock(&ocelot->mact_lock);
+
+	return err;
 }
 EXPORT_SYMBOL(ocelot_mact_forget);
 
@@ -114,7 +132,9 @@ static void ocelot_mact_init(struct ocelot *ocelot)
 		   | ANA_AGENCTRL_LEARN_IGNORE_VLAN,
 		   ANA_AGENCTRL);
 
-	/* Clear the MAC table */
+	/* Clear the MAC table. We are not concurrent with anyone, so
+	 * holding &ocelot->mact_lock is pointless.
+	 */
 	ocelot_write(ocelot, MACACCESS_CMD_INIT, ANA_TABLES_MACACCESS);
 }
 
@@ -1172,6 +1192,7 @@ EXPORT_SYMBOL(ocelot_port_fdb_do_dump);
 
 static int ocelot_mact_read(struct ocelot *ocelot, int port, int row, int col,
 			    struct ocelot_mact_entry *entry)
+	__must_hold(&ocelot->mact_lock)
 {
 	u32 val, dst, macl, mach;
 	char mac[ETH_ALEN];
@@ -1220,33 +1241,40 @@ static int ocelot_mact_read(struct ocelot *ocelot, int port, int row, int col,
 int ocelot_fdb_dump(struct ocelot *ocelot, int port,
 		    dsa_fdb_dump_cb_t *cb, void *data)
 {
+	int err = 0;
 	int i, j;
 
+	/* We could take the lock just around ocelot_mact_read, but doing so
+	 * thousands of times in a row seems rather pointless and inefficient.
+	 */
+	mutex_lock(&ocelot->mact_lock);
+
 	/* Loop through all the mac tables entries. */
 	for (i = 0; i < ocelot->num_mact_rows; i++) {
 		for (j = 0; j < 4; j++) {
 			struct ocelot_mact_entry entry;
 			bool is_static;
-			int ret;
 
-			ret = ocelot_mact_read(ocelot, port, i, j, &entry);
+			err = ocelot_mact_read(ocelot, port, i, j, &entry);
 			/* If the entry is invalid (wrong port, invalid...),
 			 * skip it.
 			 */
-			if (ret == -EINVAL)
+			if (err == -EINVAL)
 				continue;
-			else if (ret)
-				return ret;
+			else if (err)
+				break;
 
 			is_static = (entry.type == ENTRYTYPE_LOCKED);
 
-			ret = cb(entry.mac, entry.vid, is_static, data);
-			if (ret)
-				return ret;
+			err = cb(entry.mac, entry.vid, is_static, data);
+			if (err)
+				break;
 		}
 	}
 
-	return 0;
+	mutex_unlock(&ocelot->mact_lock);
+
+	return err;
 }
 EXPORT_SYMBOL(ocelot_fdb_dump);
 
@@ -2231,6 +2259,7 @@ int ocelot_init(struct ocelot *ocelot)
 
 	mutex_init(&ocelot->stats_lock);
 	mutex_init(&ocelot->ptp_lock);
+	mutex_init(&ocelot->mact_lock);
 	spin_lock_init(&ocelot->ptp_clock_lock);
 	spin_lock_init(&ocelot->ts_id_lock);
 	snprintf(queue_name, sizeof(queue_name), "%s-stats",
diff --git a/include/soc/mscc/ocelot.h b/include/soc/mscc/ocelot.h
index 9b872da0c246..fef3a36b0210 100644
--- a/include/soc/mscc/ocelot.h
+++ b/include/soc/mscc/ocelot.h
@@ -675,6 +675,9 @@ struct ocelot {
 	struct delayed_work		stats_work;
 	struct workqueue_struct		*stats_queue;
 
+	/* Lock for serializing access to the MAC table */
+	struct mutex			mact_lock;
+
 	struct workqueue_struct		*owq;
 
 	u8				ptp:1;