net/mlx4_core: Protect port type setting by mutex

We need to protect set_port_type() for concurrency, as the sysfs code could
call it from mutliple contexts in parallel.

The port_mutex is not enough because we need to protect from concurrent
modification of 'info' and stopping of the port sensing work.

Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 1 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx4/main.c b/drivers/net/ethernet/mellanox/mlx4/main.c
index 90de6e1ad06e..9f821964a1b9 100644
--- a/drivers/net/ethernet/mellanox/mlx4/main.c
+++ b/drivers/net/ethernet/mellanox/mlx4/main.c
@@ -901,9 +901,12 @@ static ssize_t set_port_type(struct device *dev,
         struct mlx4_priv *priv = mlx4_priv(mdev);
         enum mlx4_port_type types[MLX4_MAX_PORTS];
         enum mlx4_port_type new_types[MLX4_MAX_PORTS];
+        static DEFINE_MUTEX(set_port_type_mutex);
         int i;
         int err = 0;
 
+        mutex_lock(&set_port_type_mutex);
+
         if (!strcmp(buf, "ib\n"))
                 info->tmp_type = MLX4_PORT_TYPE_IB;
         else if (!strcmp(buf, "eth\n"))
@@ -912,7 +915,8 @@ static ssize_t set_port_type(struct device *dev,
                 info->tmp_type = MLX4_PORT_TYPE_AUTO;
         else {
                 mlx4_err(mdev, "%s is not supported port type\n", buf);
-                return -EINVAL;
+                err = -EINVAL;
+                goto err_out;
         }
 
         mlx4_stop_sense(mdev);
@@ -958,6 +962,9 @@ static ssize_t set_port_type(struct device *dev,
 out:
         mlx4_start_sense(mdev);
         mutex_unlock(&priv->port_mutex);
+err_out:
+        mutex_unlock(&set_port_type_mutex);
+
         return err ? err : count;
 }