Function mlx4_en_queue_bond_work() is used in mlx4_en to start a bond
reconfiguration. It gathers data about a new port map setting, takes
a reference on the netdev that triggered the change and queues a work
object on mlx4_en_priv.mdev.workqueue to perform the operation. The
scheduled work is mlx4_en_bond_work() which calls
mlx4_bond()/mlx4_unbond() and consequently mlx4_do_bond().
At the same time, function mlx4_change_port_types() in mlx4_core might
be invoked to change the port type configuration. As part of its logic,
it re-registers the whole device by calling mlx4_unregister_device(),
followed by mlx4_register_device().
The two operations can result in concurrent access to the data about
currently active interfaces on the device.
Functions mlx4_register_device() and mlx4_unregister_device() lock the
intf_mutex to gain exclusive access to this data. The current
implementation of mlx4_do_bond() doesn't do that which could result in
an unexpected behavior. An updated version of mlx4_do_bond() for use
with an auxiliary bus goes and locks the intf_mutex when accessing a new
auxiliary device array.
However, doing so can then result in the following deadlock:
* A two-port mlx4 device is configured as an Ethernet bond.
* One of the ports is changed from eth to ib, for instance, by writing
into a mlx4_port<x> sysfs attribute file.
* mlx4_change_port_types() is called to update port types. It invokes
mlx4_unregister_device() to unregister the device which locks the
intf_mutex and starts removing all associated interfaces.
* Function mlx4_en_remove() gets invoked and starts destroying its first
netdev. This triggers mlx4_en_netdev_event() which recognizes that the
configured bond is broken. It runs mlx4_en_queue_bond_work() which
takes a reference on the netdev. Removing the netdev now cannot
proceed until the work is completed.
* Work function mlx4_en_bond_work() gets scheduled. It calls
mlx4_unbond() -> mlx4_do_bond(). The latter function tries to lock the
intf_mutex but that is not possible because it is held already by
mlx4_unregister_device().
This particular case could be possibly solved by unregistering the
mlx4_en_netdev_event() notifier in mlx4_en_remove() earlier, but it
seems better to decouple mlx4_en more and break this reference order.
Avoid then this scenario by recognizing that the bond reconfiguration
operates only on a mlx4_dev. The logic to queue and execute the bond
work can be moved into the mlx4_core driver. Only a reference on the
respective mlx4_dev object is needed to be taken during the work's
lifetime. This removes a call from mlx4_en that can directly result in
needing to lock the intf_mutex, it remains a privilege of the core
driver.
Signed-off-by: Petr Pavlu <petr.pavlu@xxxxxxxx>
Tested-by: Leon Romanovsky <leon@xxxxxxxxxx>
---
.../net/ethernet/mellanox/mlx4/en_netdev.c | 62 +-----------------
drivers/net/ethernet/mellanox/mlx4/main.c | 65 +++++++++++++++++--
drivers/net/ethernet/mellanox/mlx4/mlx4.h | 5 ++
include/linux/mlx4/device.h | 13 ++++
include/linux/mlx4/driver.h | 19 ------
5 files changed, 77 insertions(+), 87 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
index 7066c426b95c..33bbcced8105 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
@@ -2894,63 +2894,6 @@ static const struct xdp_metadata_ops mlx4_xdp_metadata_ops = {
.xmo_rx_hash = mlx4_en_xdp_rx_hash,
};
-struct mlx4_en_bond {
- struct work_struct work;
- struct mlx4_en_priv *priv;
- int is_bonded;
- struct mlx4_port_map port_map;
-};
-
-static void mlx4_en_bond_work(struct work_struct *work)
-{
- struct mlx4_en_bond *bond = container_of(work,
- struct mlx4_en_bond,
- work);
- int err = 0;
- struct mlx4_dev *dev = bond->priv->mdev->dev;
-
- if (bond->is_bonded) {
- if (!mlx4_is_bonded(dev)) {
- err = mlx4_bond(dev);
- if (err)
- en_err(bond->priv, "Fail to bond device\n");
- }
- if (!err) {
- err = mlx4_port_map_set(dev, &bond->port_map);
- if (err)
- en_err(bond->priv, "Fail to set port map [%d][%d]: %d\n",
- bond->port_map.port1,
- bond->port_map.port2,
- err);
- }
- } else if (mlx4_is_bonded(dev)) {
- err = mlx4_unbond(dev);
- if (err)
- en_err(bond->priv, "Fail to unbond device\n");
- }
- dev_put(bond->priv->dev);
- kfree(bond);
-}
-
-static int mlx4_en_queue_bond_work(struct mlx4_en_priv *priv, int is_bonded,
- u8 v2p_p1, u8 v2p_p2)
-{
- struct mlx4_en_bond *bond;
-
- bond = kzalloc(sizeof(*bond), GFP_ATOMIC);
- if (!bond)
- return -ENOMEM;
-
- INIT_WORK(&bond->work, mlx4_en_bond_work);
- bond->priv = priv;
- bond->is_bonded = is_bonded;
- bond->port_map.port1 = v2p_p1;
- bond->port_map.port2 = v2p_p2;
- dev_hold(priv->dev);
- queue_work(priv->mdev->workqueue, &bond->work);
- return 0;
-}
-
int mlx4_en_netdev_event(struct notifier_block *this,
unsigned long event, void *ptr)
{
@@ -2960,7 +2903,6 @@ int mlx4_en_netdev_event(struct notifier_block *this,
struct mlx4_dev *dev;
int i, num_eth_ports = 0;
bool do_bond = true;
- struct mlx4_en_priv *priv;
u8 v2p_port1 = 0;
u8 v2p_port2 = 0;
@@ -2995,7 +2937,6 @@ int mlx4_en_netdev_event(struct notifier_block *this,
if ((do_bond && (event != NETDEV_BONDING_INFO)) || !port)
return NOTIFY_DONE;
- priv = netdev_priv(ndev);
if (do_bond) {
struct netdev_notifier_bonding_info *notifier_info = ptr;
struct netdev_bonding_info *bonding_info =
@@ -3062,8 +3003,7 @@ int mlx4_en_netdev_event(struct notifier_block *this,
}
}
- mlx4_en_queue_bond_work(priv, do_bond,
- v2p_port1, v2p_port2);
+ mlx4_queue_bond_work(dev, do_bond, v2p_port1, v2p_port2);
return NOTIFY_DONE;
}
diff --git a/drivers/net/ethernet/mellanox/mlx4/main.c b/drivers/net/ethernet/mellanox/mlx4/main.c
index 5f3ba8385e23..0ed490b99163 100644
--- a/drivers/net/ethernet/mellanox/mlx4/main.c
+++ b/drivers/net/ethernet/mellanox/mlx4/main.c
@@ -1441,7 +1441,7 @@ static int mlx4_mf_unbond(struct mlx4_dev *dev)
return ret;
}
-int mlx4_bond(struct mlx4_dev *dev)
+static int mlx4_bond(struct mlx4_dev *dev)
{
int ret = 0;
struct mlx4_priv *priv = mlx4_priv(dev);
@@ -1467,9 +1467,8 @@ int mlx4_bond(struct mlx4_dev *dev)
return ret;
}
-EXPORT_SYMBOL_GPL(mlx4_bond);
-int mlx4_unbond(struct mlx4_dev *dev)
+static int mlx4_unbond(struct mlx4_dev *dev)
{
int ret = 0;
struct mlx4_priv *priv = mlx4_priv(dev);
@@ -1496,10 +1495,8 @@ int mlx4_unbond(struct mlx4_dev *dev)
return ret;
}
-EXPORT_SYMBOL_GPL(mlx4_unbond);
-
-int mlx4_port_map_set(struct mlx4_dev *dev, struct mlx4_port_map *v2p)
+static int mlx4_port_map_set(struct mlx4_dev *dev, struct mlx4_port_map *v2p)
{
u8 port1 = v2p->port1;
u8 port2 = v2p->port2;
@@ -1541,7 +1538,61 @@ int mlx4_port_map_set(struct mlx4_dev *dev, struct mlx4_port_map *v2p)
mutex_unlock(&priv->bond_mutex);
return err;
}
-EXPORT_SYMBOL_GPL(mlx4_port_map_set);
+
+struct mlx4_bond {
+ struct work_struct work;
+ struct mlx4_dev *dev;
+ int is_bonded;
+ struct mlx4_port_map port_map;
+};
+
+static void mlx4_bond_work(struct work_struct *work)
+{
+ struct mlx4_bond *bond = container_of(work, struct mlx4_bond, work);
+ int err = 0;
+
+ if (bond->is_bonded) {
+ if (!mlx4_is_bonded(bond->dev)) {
+ err = mlx4_bond(bond->dev);
+ if (err)
+ mlx4_err(bond->dev, "Fail to bond device\n");
+ }
+ if (!err) {
+ err = mlx4_port_map_set(bond->dev, &bond->port_map);
+ if (err)
+ mlx4_err(bond->dev,
+ "Fail to set port map [%d][%d]: %d\n",
+ bond->port_map.port1,
+ bond->port_map.port2, err);
+ }
+ } else if (mlx4_is_bonded(bond->dev)) {
+ err = mlx4_unbond(bond->dev);
+ if (err)
+ mlx4_err(bond->dev, "Fail to unbond device\n");
+ }
+ put_device(&bond->dev->persist->pdev->dev);
+ kfree(bond);
+}
+
+int mlx4_queue_bond_work(struct mlx4_dev *dev, int is_bonded, u8 v2p_p1,
+ u8 v2p_p2)
+{
+ struct mlx4_bond *bond;
+
+ bond = kzalloc(sizeof(*bond), GFP_ATOMIC);
+ if (!bond)
+ return -ENOMEM;
+
+ INIT_WORK(&bond->work, mlx4_bond_work);
+ get_device(&dev->persist->pdev->dev);
+ bond->dev = dev;
+ bond->is_bonded = is_bonded;
+ bond->port_map.port1 = v2p_p1;
+ bond->port_map.port2 = v2p_p2;
+ queue_work(mlx4_wq, &bond->work);
+ return 0;
+}
+EXPORT_SYMBOL(mlx4_queue_bond_work);
static int mlx4_load_fw(struct mlx4_dev *dev)
{
diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4.h b/drivers/net/ethernet/mellanox/mlx4/mlx4.h
index 10f12e4992f1..ece9acb6a869 100644
--- a/drivers/net/ethernet/mellanox/mlx4/mlx4.h
+++ b/drivers/net/ethernet/mellanox/mlx4/mlx4.h
@@ -863,6 +863,11 @@ struct mlx4_steer {
struct list_head steer_entries[MLX4_NUM_STEERS];
};
+struct mlx4_port_map {
+ u8 port1;
+ u8 port2;
+};
+
enum {
MLX4_PCI_DEV_IS_VF = 1 << 0,
MLX4_PCI_DEV_FORCE_SENSE_PORT = 1 << 1,
diff --git a/include/linux/mlx4/device.h b/include/linux/mlx4/device.h
index 6646634a0b9d..049d8a4b044d 100644
--- a/include/linux/mlx4/device.h
+++ b/include/linux/mlx4/device.h
@@ -1087,6 +1087,19 @@ static inline void *mlx4_buf_offset(struct mlx4_buf *buf, int offset)
(offset & (PAGE_SIZE - 1));
}
+static inline int mlx4_is_bonded(struct mlx4_dev *dev)
+{
+ return !!(dev->flags & MLX4_FLAG_BONDED);
+}
+
+static inline int mlx4_is_mf_bonded(struct mlx4_dev *dev)
+{
+ return (mlx4_is_bonded(dev) && mlx4_is_mfunc(dev));
+}
+
+int mlx4_queue_bond_work(struct mlx4_dev *dev, int is_bonded, u8 v2p_p1,
+ u8 v2p_p2);
+
int mlx4_pd_alloc(struct mlx4_dev *dev, u32 *pdn);
void mlx4_pd_free(struct mlx4_dev *dev, u32 pdn);
int mlx4_xrcd_alloc(struct mlx4_dev *dev, u32 *xrcdn);
diff --git a/include/linux/mlx4/driver.h b/include/linux/mlx4/driver.h
index 0f8c9ba4c574..781d5a0c2faa 100644
--- a/include/linux/mlx4/driver.h
+++ b/include/linux/mlx4/driver.h
@@ -66,25 +66,6 @@ struct mlx4_interface {
int mlx4_register_interface(struct mlx4_interface *intf);
void mlx4_unregister_interface(struct mlx4_interface *intf);
-int mlx4_bond(struct mlx4_dev *dev);
-int mlx4_unbond(struct mlx4_dev *dev);
-static inline int mlx4_is_bonded(struct mlx4_dev *dev)
-{
- return !!(dev->flags & MLX4_FLAG_BONDED);
-}
-
-static inline int mlx4_is_mf_bonded(struct mlx4_dev *dev)
-{
- return (mlx4_is_bonded(dev) && mlx4_is_mfunc(dev));
-}
-
-struct mlx4_port_map {
- u8 port1;
- u8 port2;
-};
-
-int mlx4_port_map_set(struct mlx4_dev *dev, struct mlx4_port_map *v2p);
-
int mlx4_register_event_notifier(struct mlx4_dev *dev,
struct notifier_block *nb);
int mlx4_unregister_event_notifier(struct mlx4_dev *dev,
--
2.35.3
