[PATCH rdma-next v1] RDMA/mlx5: Annotate lock dependency in bind/unbind slave port

[PATCH rdma-next v1] RDMA/mlx5: Annotate lock dependency in bind/unbind slave port

[Leon Romanovsky]

From: Leon Romanovsky <leonro@mellanox.com>

NULL-ing notifier_call is performed under protection
of mlx5_ib_multiport_mutex lock. Such protection is
not easily spotted and better to be guarded by lockdep
annotation.

Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
---
 Changelog v1:
 * Removed comments as we added lockdep annotations
 * Added lockdep to bind port flow too
 * https://lore.kernel.org/linux-rdma/20190808083907.29316-1-leon@kernel.org
---
 drivers/infiniband/hw/mlx5/main.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c
index 7933534be931..e3a57646ddd3 100644
--- a/drivers/infiniband/hw/mlx5/main.c
+++ b/drivers/infiniband/hw/mlx5/main.c
@@ -5825,7 +5825,6 @@ static void init_delay_drop(struct mlx5_ib_dev *dev)
 		mlx5_ib_warn(dev, "Failed to init delay drop debugfs\n");
 }

-/* The mlx5_ib_multiport_mutex should be held when calling this function */
 static void mlx5_ib_unbind_slave_port(struct mlx5_ib_dev *ibdev,
 				      struct mlx5_ib_multiport_info *mpi)
 {
@@ -5835,6 +5834,8 @@ static void mlx5_ib_unbind_slave_port(struct mlx5_ib_dev *ibdev,
 	int err;
 	int i;

+	lockdep_assert_held(&mlx5_ib_multiport_mutex);
+
 	mlx5_ib_cleanup_cong_debugfs(ibdev, port_num);

 	spin_lock(&port->mp.mpi_lock);
@@ -5884,13 +5885,14 @@ static void mlx5_ib_unbind_slave_port(struct mlx5_ib_dev *ibdev,
 	ibdev->port[port_num].roce.last_port_state = IB_PORT_DOWN;
 }

-/* The mlx5_ib_multiport_mutex should be held when calling this function */
 static bool mlx5_ib_bind_slave_port(struct mlx5_ib_dev *ibdev,
 				    struct mlx5_ib_multiport_info *mpi)
 {
 	u8 port_num = mlx5_core_native_port_num(mpi->mdev) - 1;
 	int err;

+	lockdep_assert_held(&mlx5_ib_multiport_mutex);
+
 	spin_lock(&ibdev->port[port_num].mp.mpi_lock);
 	if (ibdev->port[port_num].mp.mpi) {
 		mlx5_ib_dbg(ibdev, "port %d already affiliated.\n",
--
2.20.1

Re: [PATCH rdma-next v1] RDMA/mlx5: Annotate lock dependency in bind/unbind slave port

[Doug Ledford]

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On Tue, 2019-08-13 at 13:28 +0300, Leon Romanovsky wrote:
> From: Leon Romanovsky <leonro@mellanox.com>
> 
> NULL-ing notifier_call is performed under protection
> of mlx5_ib_multiport_mutex lock. Such protection is
> not easily spotted and better to be guarded by lockdep
> annotation.
> 
> Signed-off-by: Leon Romanovsky <leonro@mellanox.com>

Thanks, applied to for-next.

-- 
Doug Ledford <dledford@redhat.com>
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