net/mlx4_en: initialize cmd.context_lock spinlock earlier

Maciej Żenczykowski reported lockdep warning a spinlock
was not registered before being held in mlx4_cmd_wake_completions()

cmd.context_lock initialization is not at the right place.

1) mlx4_cmd_use_events() can be called multiple times.
   Calling spin_lock_init() on a live spinlock can lead
   to hangs.

2) mlx4_cmd_wake_completions() can be called while lock
   has not been initialized.
   Lockdep complains, and current logic is not race prone.

It seems better to move the initialization earlier in
mlx4_load_one()
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: NMaciej Żenczykowski <maze@google.com>
Cc: Eugenia Emantayev <eugenia@mellanox.com>
Cc: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx4/cmd.c

@@ -2597,7 +2597,6 @@ int mlx4_cmd_use_events(struct mlx4_dev *dev)
 	priv->cmd.free_head = 0;
 
 	sema_init(&priv->cmd.event_sem, priv->cmd.max_cmds);
-	spin_lock_init(&priv->cmd.context_lock);
 
 	for (priv->cmd.token_mask = 1;
 	     priv->cmd.token_mask < priv->cmd.max_cmds;

drivers/net/ethernet/mellanox/mlx4/main.c

@@ -3222,6 +3222,7 @@ static int mlx4_load_one(struct pci_dev *pdev, int pci_dev_data,
 
 	INIT_LIST_HEAD(&priv->pgdir_list);
 	mutex_init(&priv->pgdir_mutex);
+	spin_lock_init(&priv->cmd.context_lock);
 
 	INIT_LIST_HEAD(&priv->bf_list);
 	mutex_init(&priv->bf_mutex);