datapath: Hold dp->mutex when calling new_vport().

On datapath creation we hold dp_mutex but not dp->mutex when
creating the vport for the datapath device.  However, there are
lockdep checks that validate that we hold dp->mutex during the call
to new_vport().  The lock isn't actually necessary in this case
because no one else can access the datapath but it's good to have
the lock assertions, so this holds dp->mutex while initializing
the datapath.

Found with lockdep.

Signed-off-by: Jesse Gross <jesse@nicira.com>
Acked-by: Ben Pfaff <blp@nicira.com>

diff --git a/datapath/datapath.c b/datapath/datapath.c
index 67f6730..d56bbf7 100644 (file)
--- a/datapath/datapath.c
+++ b/datapath/datapath.c
@@ -248,6 +248,7 @@ static int create_dp(int dp_idx, const char __user *devnamep)
                goto err_put_module;
        INIT_LIST_HEAD(&dp->port_list);
        mutex_init(&dp->mutex);
+       mutex_lock(&dp->mutex);
        dp->dp_idx = dp_idx;
        for (i = 0; i < DP_N_QUEUES; i++)
                skb_queue_head_init(&dp->queues[i]);
@@ -286,6 +287,7 @@ static int create_dp(int dp_idx, const char __user *devnamep)
        rcu_assign_pointer(dps[dp_idx], dp);
        dp_sysfs_add_dp(dp);
 
+       mutex_unlock(&dp->mutex);
        mutex_unlock(&dp_mutex);
        rtnl_unlock();
 
@@ -296,6 +298,7 @@ err_destroy_local_port:
 err_destroy_table:
        tbl_destroy(get_table_protected(dp), NULL);
 err_free_dp:
+       mutex_unlock(&dp->mutex);
        kfree(dp);
 err_put_module:
        module_put(THIS_MODULE);
@@ -348,7 +351,7 @@ out:
        return err;
 }
 
-/* Called with RTNL lock and dp_mutex. */
+/* Called with RTNL lock and dp->mutex. */
 static int new_vport(struct datapath *dp, struct odp_port *odp_port, int port_no)
 {
        struct vport_parms parms;