Commit 0c5ddb51 authored Jun 13, 2016 by Eric Dumazet Committed by David S. Miller Jun 15, 2016

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: Eric Dumazet <edumazet@google.com>
Reported-by: Maciej Żenczykowski <maze@google.com>
Cc: Eugenia Emantayev <eugenia@mellanox.com>
Cc: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 61e0979a

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

+0 −1

Original line number	Diff line number	Diff line
		@@ -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

+1 −0

Original line number	Diff line number	Diff line
		@@ -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);