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net/mlx5: Use devl_ API in mlx5e_devlink_port_register

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As part of the flows invoked by mlx5_devlink_eswitch_mode_set() get to
mlx5_rescan_drivers_locked() which can call mlx5e_probe()/mlx5e_remove
and register/unregister mlx5e driver ports accordingly. This can lead to
deadlock once mlx5_devlink_eswitch_mode_set() will use devlink lock.
Use devl_port_register/unregister() instead of
devlink_port_register/unregister() and add devlink instance locks in the
driver paths to this function to have it locked while calling devl_ API
function.

If remove or probe were called by module init or module cleanup flows,
need to lock devlink just before calling devl_port_register(), otherwise
it is called by attach/detach or register/unregister flow and we can
have the flow locked. Added flag to distinguish between these cases.

This will be used by the downstream patch to invoke
mlx5_devlink_eswitch_mode_set() with devlink locked.

Signed-off-by: Moshe Shemesh <moshe@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Moshe Shemesh 2022-07-11 01:14:06 -07:00 committed by Paolo Abeni
parent df539fc62b
commit 7b19119f4c
4 changed files with 47 additions and 4 deletions
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29
drivers/net/ethernet/mellanox/mlx5/core/dev.c
View file

@ -335,13 +335,16 @@ static void del_adev(struct auxiliary_device *adev)
int mlx5_attach_device(struct mlx5_core_dev *dev)
{
struct devlink *devlink = priv_to_devlink(dev);
struct mlx5_priv *priv = &dev->priv;
struct auxiliary_device *adev;
struct auxiliary_driver *adrv;
int ret = 0, i;
devl_lock(devlink);
mutex_lock(&mlx5_intf_mutex);
priv->flags &= ~MLX5_PRIV_FLAGS_DETACH;
priv->flags |= MLX5_PRIV_FLAGS_MLX5E_LOCKED_FLOW;
for (i = 0; i < ARRAY_SIZE(mlx5_adev_devices); i++) {
if (!priv->adev[i]) {
bool is_supported = false;
@ -389,19 +392,24 @@ int mlx5_attach_device(struct mlx5_core_dev *dev)
break;
}
}
priv->flags &= ~MLX5_PRIV_FLAGS_MLX5E_LOCKED_FLOW;
mutex_unlock(&mlx5_intf_mutex);
devl_unlock(devlink);
return ret;
}
void mlx5_detach_device(struct mlx5_core_dev *dev)
{
struct devlink *devlink = priv_to_devlink(dev);
struct mlx5_priv *priv = &dev->priv;
struct auxiliary_device *adev;
struct auxiliary_driver *adrv;
pm_message_t pm = {};
int i;
devl_lock(devlink);
mutex_lock(&mlx5_intf_mutex);
priv->flags |= MLX5_PRIV_FLAGS_MLX5E_LOCKED_FLOW;
for (i = ARRAY_SIZE(mlx5_adev_devices) - 1; i >= 0; i--) {
if (!priv->adev[i])
continue;
@ -430,18 +438,24 @@ void mlx5_detach_device(struct mlx5_core_dev *dev)
del_adev(&priv->adev[i]->adev);
priv->adev[i] = NULL;
}
priv->flags &= ~MLX5_PRIV_FLAGS_MLX5E_LOCKED_FLOW;
priv->flags |= MLX5_PRIV_FLAGS_DETACH;
mutex_unlock(&mlx5_intf_mutex);
devl_unlock(devlink);
}
int mlx5_register_device(struct mlx5_core_dev *dev)
{
struct devlink *devlink;
int ret;
devlink = priv_to_devlink(dev);
devl_lock(devlink);
mutex_lock(&mlx5_intf_mutex);
dev->priv.flags &= ~MLX5_PRIV_FLAGS_DISABLE_ALL_ADEV;
ret = mlx5_rescan_drivers_locked(dev);
mutex_unlock(&mlx5_intf_mutex);
devl_unlock(devlink);
if (ret)
mlx5_unregister_device(dev);
@ -450,10 +464,15 @@ int mlx5_register_device(struct mlx5_core_dev *dev)
void mlx5_unregister_device(struct mlx5_core_dev *dev)
{
struct devlink *devlink;
devlink = priv_to_devlink(dev);
devl_lock(devlink);
mutex_lock(&mlx5_intf_mutex);
dev->priv.flags = MLX5_PRIV_FLAGS_DISABLE_ALL_ADEV;
mlx5_rescan_drivers_locked(dev);
mutex_unlock(&mlx5_intf_mutex);
devl_unlock(devlink);
}
static int add_drivers(struct mlx5_core_dev *dev)
@ -526,16 +545,22 @@ static void delete_drivers(struct mlx5_core_dev *dev)
int mlx5_rescan_drivers_locked(struct mlx5_core_dev *dev)
{
struct mlx5_priv *priv = &dev->priv;
int err = 0;
lockdep_assert_held(&mlx5_intf_mutex);
if (priv->flags & MLX5_PRIV_FLAGS_DETACH)
return 0;
priv->flags |= MLX5_PRIV_FLAGS_MLX5E_LOCKED_FLOW;
delete_drivers(dev);
if (priv->flags & MLX5_PRIV_FLAGS_DISABLE_ALL_ADEV)
return 0;
goto out;
return add_drivers(dev);
err = add_drivers(dev);
out:
priv->flags &= ~MLX5_PRIV_FLAGS_MLX5E_LOCKED_FLOW;
return err;
}
bool mlx5_same_hw_devs(struct mlx5_core_dev *dev, struct mlx5_core_dev *peer_dev)

16
drivers/net/ethernet/mellanox/mlx5/core/en/devlink.c
View file

@ -21,6 +21,7 @@ int mlx5e_devlink_port_register(struct mlx5e_priv *priv)
struct netdev_phys_item_id ppid = {};
struct devlink_port *dl_port;
unsigned int dl_port_index;
int ret;
if (mlx5_core_is_pf(priv->mdev)) {
attrs.flavour = DEVLINK_PORT_FLAVOUR_PHYSICAL;
@ -41,7 +42,13 @@ int mlx5e_devlink_port_register(struct mlx5e_priv *priv)
memset(dl_port, 0, sizeof(*dl_port));
devlink_port_attrs_set(dl_port, &attrs);
return devlink_port_register(devlink, dl_port, dl_port_index);
if (!(priv->mdev->priv.flags & MLX5_PRIV_FLAGS_MLX5E_LOCKED_FLOW))
devl_lock(devlink);
ret = devl_port_register(devlink, dl_port, dl_port_index);
if (!(priv->mdev->priv.flags & MLX5_PRIV_FLAGS_MLX5E_LOCKED_FLOW))
devl_unlock(devlink);
return ret;
}
void mlx5e_devlink_port_type_eth_set(struct mlx5e_priv *priv)
@ -54,8 +61,13 @@ void mlx5e_devlink_port_type_eth_set(struct mlx5e_priv *priv)
void mlx5e_devlink_port_unregister(struct mlx5e_priv *priv)
{
struct devlink_port *dl_port = mlx5e_devlink_get_dl_port(priv);
struct devlink *devlink = priv_to_devlink(priv->mdev);
devlink_port_unregister(dl_port);
if (!(priv->mdev->priv.flags & MLX5_PRIV_FLAGS_MLX5E_LOCKED_FLOW))
devl_lock(devlink);
devl_port_unregister(dl_port);
if (!(priv->mdev->priv.flags & MLX5_PRIV_FLAGS_MLX5E_LOCKED_FLOW))
devl_unlock(devlink);
}
struct devlink_port *mlx5e_get_devlink_port(struct net_device *dev)

2
drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c
View file

@ -3400,7 +3400,9 @@ int mlx5_devlink_eswitch_mode_set(struct devlink *devlink, u16 mode,
err = esw_offloads_start(esw, extack);
} else if (mode == DEVLINK_ESWITCH_MODE_LEGACY) {
err = esw_offloads_stop(esw, extack);
devl_lock(devlink);
mlx5_rescan_drivers(esw->dev);
devl_unlock(devlink);
} else {
err = -EINVAL;
}

4
include/linux/mlx5/driver.h
View file

@ -551,6 +551,10 @@ enum {
* creation/deletion on drivers rescan. Unset during device attach.
*/
MLX5_PRIV_FLAGS_DETACH = 1 << 2,
/* Distinguish between mlx5e_probe/remove called by module init/cleanup
* and called by other flows which can already hold devlink lock
*/
MLX5_PRIV_FLAGS_MLX5E_LOCKED_FLOW = 1 << 3,
};
struct mlx5_adev {