[ 043/221] IB/mlx4: Fix spinlock order to avoid lockdep warnings

Greg Kroah-Hartman
2013-01-16T00:35:40Z

From: Jack Morgenstein <jackm@dev.mellanox.co.il>

commit ceb7decb366591e9b67d70832e07f5d240572a3d upstream.

lockdep warns about taking a hard-irq-unsafe lock (sriov->id_map_lock)
inside a hard-irq-safe lock (sriov->going_down_lock).

Since id_map_lock is never taken in the interrupt context, we can
simply reverse the order of taking the two spinlocks, thus avoiding
the warning and the depencency.

Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/infiniband/hw/mlx4/cm.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/infiniband/hw/mlx4/cm.c
+++ b/drivers/infiniband/hw/mlx4/cm.c
@@ -268,15 +268,15 @@ static void schedule_delayed(struct ib_d
struct mlx4_ib_sriov *sriov = &to_mdev(ibdev)->sriov;
unsigned long flags;

- spin_lock_irqsave(&sriov->going_down_lock, flags);
spin_lock(&sriov->id_map_lock);
+ spin_lock_irqsave(&sriov->going_down_lock, flags);
/*make sure that there is no schedule inside the scheduled work.*/
if (!sriov->is_going_down) {
id->scheduled_delete = 1;
schedule_delayed_work(&id->timeout, CM_CLEANUP_CACHE_TIMEOUT);
}
- spin_unlock(&sriov->id_map_lock);
spin_unlock_irqrestore(&sriov->going_down_lock, flags);
+ spin_unlock(&sriov->id_map_lock);
}

int mlx4_ib_multiplex_cm_handler(struct ib_device *ibdev, int port, int slave_id,