net: core: devlink.c: Hold devlink->lock from the beginning of devlink_dpipe_table_re...

devlink_dpipe_table_find() should be called under either
rcu_read_lock() or devlink->lock. devlink_dpipe_table_register()
calls devlink_dpipe_table_find() without holding the lock
and acquires it later. Therefore hold the devlink->lock
from the beginning of devlink_dpipe_table_register().

Suggested-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/devlink.c b/net/core/devlink.c
index 549ee56..8d0b558 100644 (file)
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -6878,26 +6878,33 @@ int devlink_dpipe_table_register(struct devlink *devlink,
                                 void *priv, bool counter_control_extern)
 {
        struct devlink_dpipe_table *table;
-
-       if (devlink_dpipe_table_find(&devlink->dpipe_table_list, table_name))
-               return -EEXIST;
+       int err = 0;
 
        if (WARN_ON(!table_ops->size_get))
                return -EINVAL;
 
+       mutex_lock(&devlink->lock);
+
+       if (devlink_dpipe_table_find(&devlink->dpipe_table_list, table_name)) {
+               err = -EEXIST;
+               goto unlock;
+       }
+
        table = kzalloc(sizeof(*table), GFP_KERNEL);
-       if (!table)
-               return -ENOMEM;
+       if (!table) {
+               err = -ENOMEM;
+               goto unlock;
+       }
 
        table->name = table_name;
        table->table_ops = table_ops;
        table->priv = priv;
        table->counter_control_extern = counter_control_extern;
 
-       mutex_lock(&devlink->lock);
        list_add_tail_rcu(&table->list, &devlink->dpipe_table_list);
+unlock:
        mutex_unlock(&devlink->lock);
-       return 0;
+       return err;
 }
 EXPORT_SYMBOL_GPL(devlink_dpipe_table_register);