On Sun, Aug 13, 2023 at 04:51:20PM +0200, Petr Pavlu wrote:
> Use a notifier to implement mlx4_dispatch_event() in preparation to
> switch mlx4_en and mlx4_ib to be an auxiliary device.
>
> A problem is that if the mlx4_interface.event callback was replaced with
> something as mlx4_adrv.event then the implementation of
> mlx4_dispatch_event() would need to acquire a lock on a given device
> before executing this callback. That is necessary because otherwise
> there is no guarantee that the associated driver cannot get unbound when
> the callback is running. However, taking this lock is not possible
> because mlx4_dispatch_event() can be invoked from the hardirq context.
> Using an atomic notifier allows the driver to accurately record when it
> wants to receive these events and solves this problem.
>
> A handler registration is done by both mlx4_en and mlx4_ib at the end of
> their mlx4_interface.add callback. This matches the current situation
> when mlx4_add_device() would enable events for a given device
> immediately after this callback, by adding the device on the
> mlx4_priv.list.
>
> Signed-off-by: Petr Pavlu <petr.pavlu@xxxxxxxx>
> Tested-by: Leon Romanovsky <leonro@xxxxxxxxxx>
> Acked-by: Tariq Toukan <tariqt@xxxxxxxxxx>
> ---
> drivers/infiniband/hw/mlx4/main.c | 41 +++++++++++++-------
> drivers/infiniband/hw/mlx4/mlx4_ib.h | 2 +
> drivers/net/ethernet/mellanox/mlx4/en_main.c | 27 +++++++++----
> drivers/net/ethernet/mellanox/mlx4/intf.c | 24 ++++++++----
> drivers/net/ethernet/mellanox/mlx4/main.c | 2 +
> drivers/net/ethernet/mellanox/mlx4/mlx4.h | 2 +
> drivers/net/ethernet/mellanox/mlx4/mlx4_en.h | 2 +
> include/linux/mlx4/driver.h | 8 +++-
> 8 files changed, 77 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/infiniband/hw/mlx4/main.c b/drivers/infiniband/hw/mlx4/main.c
> index 7dd70d778b6b..0761c465120b 100644
> --- a/drivers/infiniband/hw/mlx4/main.c
> +++ b/drivers/infiniband/hw/mlx4/main.c
> @@ -82,6 +82,8 @@ static const char mlx4_ib_version[] =
> static void do_slave_init(struct mlx4_ib_dev *ibdev, int slave, int do_init);
> static enum rdma_link_layer mlx4_ib_port_link_layer(struct ib_device *device,
> u32 port_num);
> +static int mlx4_ib_event(struct notifier_block *this, unsigned long event,
> + void *ptr);
>
> static struct workqueue_struct *wq;
>
> @@ -2836,6 +2838,12 @@ static void *mlx4_ib_add(struct mlx4_dev *dev)
> do_slave_init(ibdev, j, 1);
> }
> }
> +
> + /* register mlx4 core notifier */
> + ibdev->mlx_nb.notifier_call = mlx4_ib_event;
> + err = mlx4_register_event_notifier(dev, &ibdev->mlx_nb);
> + WARN(err, "failed to register mlx4 event notifier (%d)", err);
> +
> return ibdev;
>
> err_notif:
> @@ -2953,6 +2961,8 @@ static void mlx4_ib_remove(struct mlx4_dev *dev, void *ibdev_ptr)
> int p;
> int i;
>
> + mlx4_unregister_event_notifier(dev, &ibdev->mlx_nb);
> +
> mlx4_foreach_port(i, dev, MLX4_PORT_TYPE_IB)
> devlink_port_type_clear(mlx4_get_devlink_port(dev, i));
> ibdev->ib_active = false;
> @@ -3173,11 +3183,14 @@ void mlx4_sched_ib_sl2vl_update_work(struct mlx4_ib_dev *ibdev,
> }
> }
>
> -static void mlx4_ib_event(struct mlx4_dev *dev, void *ibdev_ptr,
> - enum mlx4_dev_event event, unsigned long param)
> +static int mlx4_ib_event(struct notifier_block *this, unsigned long event,
> + void *ptr)
> {
> + struct mlx4_ib_dev *ibdev =
> + container_of(this, struct mlx4_ib_dev, mlx_nb);
> + struct mlx4_dev *dev = ibdev->dev;
> + unsigned long param = *(unsigned long *)ptr;
You don't need this assignment here as later, you will cast param again,
in your next patches:
3227 if (event == MLX4_DEV_EVENT_PORT_MGMT_CHANGE)
3228 eqe = (struct mlx4_eqe *)param;
3229 else
3230 p = (int) param;
so use ptr directly:
if (event == MLX4_DEV_EVENT_PORT_MGMT_CHANGE)
eqe = param;
else
p = *(int *) param;
Thanks
