[PATCH net-next] net: dsa: mv88e6xxx: lock mutex in port_fdb_dump

[Vivien Didelot]

During a port FDB dump operation, the mutex protecting the concurrent
access to the switch registers is currently held by the internal
mv88e6xxx_port_db_dump and mv88e6xxx_port_db_dump_fid helpers.

It must be held at the higher level in mv88e6xxx_port_fdb_dump which
is called directly by DSA through ds->ops->port_fdb_dump. Fix this.

Signed-off-by: Vivien Didelot <vivien.dide...@gmail.com>
---
 drivers/net/dsa/mv88e6xxx/chip.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index 4b2f8d6f0744..6691120bd283 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -1767,9 +1767,7 @@ static int mv88e6xxx_port_db_dump_fid(struct 
mv88e6xxx_chip *chip,
        eth_broadcast_addr(addr.mac);
 
        do {
-               mutex_lock(&chip->reg_lock);
                err = mv88e6xxx_g1_atu_getnext(chip, fid, &addr);
-               mutex_unlock(&chip->reg_lock);
                if (err)
                        return err;
 
@@ -1802,10 +1800,7 @@ static int mv88e6xxx_port_db_dump(struct mv88e6xxx_chip 
*chip, int port,
        int err;
 
        /* Dump port's default Filtering Information Database (VLAN ID 0) */
-       mutex_lock(&chip->reg_lock);
        err = mv88e6xxx_port_get_fid(chip, port, &fid);
-       mutex_unlock(&chip->reg_lock);
-
        if (err)
                return err;
 
@@ -1815,9 +1810,7 @@ static int mv88e6xxx_port_db_dump(struct mv88e6xxx_chip 
*chip, int port,
 
        /* Dump VLANs' Filtering Information Databases */
        do {
-               mutex_lock(&chip->reg_lock);
                err = mv88e6xxx_vtu_getnext(chip, &vlan);
-               mutex_unlock(&chip->reg_lock);
                if (err)
                        return err;
 
@@ -1837,8 +1830,13 @@ static int mv88e6xxx_port_fdb_dump(struct dsa_switch 
*ds, int port,
                                   dsa_fdb_dump_cb_t *cb, void *data)
 {
        struct mv88e6xxx_chip *chip = ds->priv;
+       int err;
 
-       return mv88e6xxx_port_db_dump(chip, port, cb, data);
+       mutex_lock(&chip->reg_lock);
+       err = mv88e6xxx_port_db_dump(chip, port, cb, data);
+       mutex_unlock(&chip->reg_lock);
+
+       return err;
 }
 
 static int mv88e6xxx_bridge_map(struct mv88e6xxx_chip *chip,
-- 
2.21.0