From: Moshe Shemesh <moshe@nvidia.com>
Date: Mon, 11 Jul 2022 01:14:06 -0700
Subject: net/mlx5: Use devl_ API in mlx5e_devlink_port_register
Patch-mainline: v6.0-rc1
Git-commit: 7b19119f4c7dc9412b556ea12fae6b32574e2810
References: jsc#PED-1549
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>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
drivers/net/ethernet/mellanox/mlx5/core/dev.c | 29 ++++++++++++-
drivers/net/ethernet/mellanox/mlx5/core/en/devlink.c | 16 ++++++-
drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c | 2
include/linux/mlx5/driver.h | 4 +
4 files changed, 47 insertions(+), 4 deletions(-)
--- a/drivers/net/ethernet/mellanox/mlx5/core/dev.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/dev.c
@@ -335,13 +335,16 @@ static void del_adev(struct auxiliary_de
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_
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 @@ skip_suspend:
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_cor
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 @@ del_adev:
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;
+
+ err = add_drivers(dev);
- return 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)
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/devlink.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/devlink.c
@@ -21,6 +21,7 @@ int mlx5e_devlink_port_register(struct m
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 m
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(str
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)
--- a/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads.c
@@ -3400,7 +3400,9 @@ int mlx5_devlink_eswitch_mode_set(struct
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;
}
--- a/include/linux/mlx5/driver.h
+++ b/include/linux/mlx5/driver.h
@@ -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 {