[patch net-next v2 05/13] net: devlink: track netdev with devlink_port assigned

Jiri Pirko
2022-10-03T10:52:28Z

Currently, ethernet drivers are using devlink_port_type_eth_set() and
devlink_port_type_clear() to set devlink port type and link to related
netdev.

Instead of calling them directly, let the driver use
SET_NETDEV_DEVLINK_PORT macro to assign devlink_port pointer and let
devlink to track it. Note the devlink port pointer is static during
the time netdevice is registered.

In devlink code, use per-namespace netdev notifier to track
the netdevices with devlink_port assigned and change the internal
devlink_port type and related type pointer accordingly.

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
---
v1->v2:
- added kdoc for devlink_port struct field
---
include/linux/netdevice.h | 19 ++++++++++
net/core/dev.c | 11 +++---
net/core/devlink.c | 75 ++++++++++++++++++++++++++++++++++++---
3 files changed, 97 insertions(+), 8 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index eddf8ee270e7..bbb93be49063 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1999,6 +1999,11 @@ enum netdev_ml_priv_type {
* registered
* @offload_xstats_l3: L3 HW stats for this netdevice.
*
+ * @devlink_port: Pointer to related devlink port structure.
+ * Assigned by a driver before netdev registration using
+ * SET_NETDEV_DEVLINK_PORT macro. This pointer is static
+ * during the time netdevice is registered.
+ *
* FIXME: cleanup struct net_device such that network protocol info
* moves out.
*/
@@ -2349,9 +2354,22 @@ struct net_device {
netdevice_tracker watchdog_dev_tracker;
netdevice_tracker dev_registered_tracker;
struct rtnl_hw_stats64 *offload_xstats_l3;
+
+ struct devlink_port *devlink_port;
};
#define to_net_dev(d) container_of(d, struct net_device, dev)

+/*
+ * Driver should use this to assign devlink port instance to a netdevice
+ * before it registers the netdevice. Therefore devlink_port is static
+ * during the netdev lifetime after it is registered.
+ */
+#define SET_NETDEV_DEVLINK_PORT(dev, _devlink_port) \
+({ \
+ WARN_ON(dev->reg_state != NETREG_UNINITIALIZED); \
+ ((dev)->devlink_port = (_devlink_port)); \
+})
+
static inline bool netif_elide_gro(const struct net_device *dev)
{
if (!(dev->features & NETIF_F_GRO) || dev->xdp_prog)
@@ -2785,6 +2803,7 @@ enum netdev_cmd {
NETDEV_PRE_TYPE_CHANGE,
NETDEV_POST_TYPE_CHANGE,
NETDEV_POST_INIT,
+ NETDEV_PRE_UNINIT,
NETDEV_RELEASE,
NETDEV_NOTIFY_PEERS,
NETDEV_JOIN,
diff --git a/net/core/dev.c b/net/core/dev.c
index fa53830d0683..1b45aa5c976e 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1621,10 +1621,10 @@ const char *netdev_cmd_to_name(enum netdev_cmd cmd)
N(UP) N(DOWN) N(REBOOT) N(CHANGE) N(REGISTER) N(UNREGISTER)
N(CHANGEMTU) N(CHANGEADDR) N(GOING_DOWN) N(CHANGENAME) N(FEAT_CHANGE)
N(BONDING_FAILOVER) N(PRE_UP) N(PRE_TYPE_CHANGE) N(POST_TYPE_CHANGE)
- N(POST_INIT) N(RELEASE) N(NOTIFY_PEERS) N(JOIN) N(CHANGEUPPER)
- N(RESEND_IGMP) N(PRECHANGEMTU) N(CHANGEINFODATA) N(BONDING_INFO)
- N(PRECHANGEUPPER) N(CHANGELOWERSTATE) N(UDP_TUNNEL_PUSH_INFO)
- N(UDP_TUNNEL_DROP_INFO) N(CHANGE_TX_QUEUE_LEN)
+ N(POST_INIT) N(PRE_UNINIT) N(RELEASE) N(NOTIFY_PEERS) N(JOIN)
+ N(CHANGEUPPER) N(RESEND_IGMP) N(PRECHANGEMTU) N(CHANGEINFODATA)
+ N(BONDING_INFO) N(PRECHANGEUPPER) N(CHANGELOWERSTATE)
+ N(UDP_TUNNEL_PUSH_INFO) N(UDP_TUNNEL_DROP_INFO) N(CHANGE_TX_QUEUE_LEN)
N(CVLAN_FILTER_PUSH_INFO) N(CVLAN_FILTER_DROP_INFO)
N(SVLAN_FILTER_PUSH_INFO) N(SVLAN_FILTER_DROP_INFO)
N(PRE_CHANGEADDR) N(OFFLOAD_XSTATS_ENABLE) N(OFFLOAD_XSTATS_DISABLE)
@@ -10103,6 +10103,7 @@ int register_netdevice(struct net_device *dev)
return ret;

err_uninit:
+ call_netdevice_notifiers(NETDEV_PRE_UNINIT, dev);
if (dev->netdev_ops->ndo_uninit)
dev->netdev_ops->ndo_uninit(dev);
if (dev->priv_destructor)
@@ -10856,6 +10857,8 @@ void unregister_netdevice_many(struct list_head *head)
netdev_name_node_alt_flush(dev);
netdev_name_node_free(dev->name_node);

+ call_netdevice_notifiers(NETDEV_PRE_UNINIT, dev);
+
if (dev->netdev_ops->ndo_uninit)
dev->netdev_ops->ndo_uninit(dev);

diff --git a/net/core/devlink.c b/net/core/devlink.c
index ee14520d4690..87aa39bc481e 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -71,6 +71,7 @@ struct devlink {
refcount_t refcount;
struct completion comp;
struct rcu_head rcu;
+ struct notifier_block netdevice_nb;
char priv[] __aligned(NETDEV_ALIGN);
};

@@ -9615,6 +9616,9 @@ void devlink_set_features(struct devlink *devlink, u64 features)
}
EXPORT_SYMBOL_GPL(devlink_set_features);

+static int devlink_netdevice_event(struct notifier_block *nb,
+ unsigned long event, void *ptr);
+
/**
* devlink_alloc_ns - Allocate new devlink instance resources
* in specific namespace
@@ -9645,10 +9649,13 @@ struct devlink *devlink_alloc_ns(const struct devlink_ops *ops,

ret = xa_alloc_cyclic(&devlinks, &devlink->index, devlink, xa_limit_31b,
&last_id, GFP_KERNEL);
- if (ret < 0) {
- kfree(devlink);
- return NULL;
- }
+ if (ret < 0)
+ goto err_xa_alloc;
+
+ devlink->netdevice_nb.notifier_call = devlink_netdevice_event;
+ ret = register_netdevice_notifier_net(net, &devlink->netdevice_nb);
+ if (ret)
+ goto err_register_netdevice_notifier;

devlink->dev = dev;
devlink->ops = ops;
@@ -9675,6 +9682,12 @@ struct devlink *devlink_alloc_ns(const struct devlink_ops *ops,
init_completion(&devlink->comp);

return devlink;
+
+err_register_netdevice_notifier:
+ xa_erase(&devlinks, devlink->index);
+err_xa_alloc:
+ kfree(devlink);
+ return NULL;
}
EXPORT_SYMBOL_GPL(devlink_alloc_ns);

@@ -9828,6 +9841,10 @@ void devlink_free(struct devlink *devlink)
WARN_ON(!list_empty(&devlink->port_list));

xa_destroy(&devlink->snapshot_ids);
+
+ unregister_netdevice_notifier_net(devlink_net(devlink),
+ &devlink->netdevice_nb);
+
xa_erase(&devlinks, devlink->index);

kfree(devlink);
@@ -10121,6 +10138,56 @@ void devlink_port_type_clear(struct devlink_port *devlink_port)
}
EXPORT_SYMBOL_GPL(devlink_port_type_clear);

+static int devlink_netdevice_event(struct notifier_block *nb,
+ unsigned long event, void *ptr)
+{
+ struct net_device *netdev = netdev_notifier_info_to_dev(ptr);
+ struct devlink_port *devlink_port = netdev->devlink_port;
+ struct devlink *devlink;
+
+ devlink = container_of(nb, struct devlink, netdevice_nb);
+
+ if (!devlink_port || devlink_port->devlink != devlink)
+ return NOTIFY_OK;
+
+ switch (event) {
+ case NETDEV_POST_INIT:
+ /* Set the type but not netdev pointer. It is going to be set
+ * later on by NETDEV_REGISTER event. Happens once during
+ * netdevice register
+ */
+ __devlink_port_type_set(devlink_port, DEVLINK_PORT_TYPE_ETH,
+ NULL, true);
+ break;
+ case NETDEV_REGISTER:
+ /* Set the netdev on top of previously set type. Note this
+ * event happens also during net namespace change so here
+ * we take into account netdev pointer appearing in this
+ * namespace.
+ */
+ __devlink_port_type_set(devlink_port, DEVLINK_PORT_TYPE_ETH,
+ netdev, true);
+ break;
+ case NETDEV_UNREGISTER:
+ /* Clear netdev pointer, but not the type. This event happens
+ * also during net namespace change so we need to clear
+ * pointer to netdev that is going to another net namespace.
+ */
+ __devlink_port_type_set(devlink_port, DEVLINK_PORT_TYPE_ETH,
+ NULL, true);
+ break;
+ case NETDEV_PRE_UNINIT:
+ /* Clear the type and the netdev pointer. Happens one during
+ * netdevice unregister.
+ */
+ __devlink_port_type_set(devlink_port, DEVLINK_PORT_TYPE_NOTSET,
+ NULL, true);
+ break;
+ }
+
+ return NOTIFY_OK;
+}
+
static int __devlink_port_attrs_set(struct devlink_port *devlink_port,
enum devlink_port_flavour flavour)
{
--
2.37.1