Merge branch 'devlink-sanitize-per-port-region-creation-destruction'

Jiri Pirko says:

====================
devlink: sanitize per-port region creation/destruction

Currently the only user of per-port devlink regions is DSA. All drivers
that use regions register them before devlink registration. For DSA,
this was not possible as the internals of struct devlink_port needed for
region creation are initialized during port registration.

This introduced a mismatch in creation flow of devlink and devlink port
regions. As you can see, it causes the DSA driver to make the port
init/exit flow a bit cumbersome.

Fix this by introducing port_init/fini() which could be optionally
called by drivers like DSA, to prepare struct devlink_port to be used
for region creation purposes before devlink port register is called.

Tested by Vladimir on his setup.
====================

Link: https://lore.kernel.org/r/20220929072902.2986539-1-jiri@resnulli.us
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 64 insertions, 16 deletions

diff --git a/net/core/devlink.c b/net/core/devlink.c
index 7776dc82f88d..89baa7c0938b 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -371,6 +371,13 @@ static struct devlink *devlink_get_from_attrs(struct net *net,
 	return ERR_PTR(-ENODEV);
 }
 
+#define ASSERT_DEVLINK_PORT_REGISTERED(devlink_port)				\
+	WARN_ON_ONCE(!(devlink_port)->registered)
+#define ASSERT_DEVLINK_PORT_NOT_REGISTERED(devlink_port)			\
+	WARN_ON_ONCE((devlink_port)->registered)
+#define ASSERT_DEVLINK_PORT_INITIALIZED(devlink_port)				\
+	WARN_ON_ONCE(!(devlink_port)->initialized)
+
 static struct devlink_port *devlink_port_get_by_index(struct devlink *devlink,
 						      unsigned int port_index)
 {
@@ -9848,6 +9855,44 @@ static void devlink_port_type_warn_cancel(struct devlink_port *devlink_port)
 }
 
 /**
+ * devlink_port_init() - Init devlink port
+ *
+ * @devlink: devlink
+ * @devlink_port: devlink port
+ *
+ * Initialize essencial stuff that is needed for functions
+ * that may be called before devlink port registration.
+ * Call to this function is optional and not needed
+ * in case the driver does not use such functions.
+ */
+void devlink_port_init(struct devlink *devlink,
+		       struct devlink_port *devlink_port)
+{
+	if (devlink_port->initialized)
+		return;
+	devlink_port->devlink = devlink;
+	INIT_LIST_HEAD(&devlink_port->region_list);
+	devlink_port->initialized = true;
+}
+EXPORT_SYMBOL_GPL(devlink_port_init);
+
+/**
+ * devlink_port_fini() - Deinitialize devlink port
+ *
+ * @devlink_port: devlink port
+ *
+ * Deinitialize essencial stuff that is in use for functions
+ * that may be called after devlink port unregistration.
+ * Call to this function is optional and not needed
+ * in case the driver does not use such functions.
+ */
+void devlink_port_fini(struct devlink_port *devlink_port)
+{
+	WARN_ON(!list_empty(&devlink_port->region_list));
+}
+EXPORT_SYMBOL_GPL(devlink_port_fini);
+
+/**
  * devl_port_register() - Register devlink port
  *
  * @devlink: devlink
@@ -9869,14 +9914,15 @@ int devl_port_register(struct devlink *devlink,
 	if (devlink_port_index_exists(devlink, port_index))
 		return -EEXIST;
 
-	WARN_ON(devlink_port->devlink);
-	devlink_port->devlink = devlink;
+	ASSERT_DEVLINK_PORT_NOT_REGISTERED(devlink_port);
+
+	devlink_port_init(devlink, devlink_port);
+	devlink_port->registered = true;
 	devlink_port->index = port_index;
 	spin_lock_init(&devlink_port->type_lock);
 	INIT_LIST_HEAD(&devlink_port->reporter_list);
 	mutex_init(&devlink_port->reporters_lock);
 	list_add_tail(&devlink_port->list, &devlink->port_list);
-	INIT_LIST_HEAD(&devlink_port->region_list);
 
 	INIT_DELAYED_WORK(&devlink_port->type_warn_dw, &devlink_port_type_warn);
 	devlink_port_type_warn_schedule(devlink_port);
@@ -9926,8 +9972,8 @@ void devl_port_unregister(struct devlink_port *devlink_port)
 	devlink_port_notify(devlink_port, DEVLINK_CMD_PORT_DEL);
 	list_del(&devlink_port->list);
 	WARN_ON(!list_empty(&devlink_port->reporter_list));
-	WARN_ON(!list_empty(&devlink_port->region_list));
 	mutex_destroy(&devlink_port->reporters_lock);
+	devlink_port->registered = false;
 }
 EXPORT_SYMBOL_GPL(devl_port_unregister);
 
@@ -9952,8 +9998,8 @@ static void __devlink_port_type_set(struct devlink_port *devlink_port,
 				    enum devlink_port_type type,
 				    void *type_dev)
 {
-	if (WARN_ON(!devlink_port->devlink))
-		return;
+	ASSERT_DEVLINK_PORT_REGISTERED(devlink_port);
+
 	devlink_port_type_warn_cancel(devlink_port);
 	spin_lock_bh(&devlink_port->type_lock);
 	devlink_port->type = type;
@@ -10072,8 +10118,8 @@ void devlink_port_attrs_set(struct devlink_port *devlink_port,
 {
 	int ret;
 
-	if (WARN_ON(devlink_port->devlink))
-		return;
+	ASSERT_DEVLINK_PORT_NOT_REGISTERED(devlink_port);
+
 	devlink_port->attrs = *attrs;
 	ret = __devlink_port_attrs_set(devlink_port, attrs->flavour);
 	if (ret)
@@ -10096,8 +10142,8 @@ void devlink_port_attrs_pci_pf_set(struct devlink_port *devlink_port, u32 contro
 	struct devlink_port_attrs *attrs = &devlink_port->attrs;
 	int ret;
 
-	if (WARN_ON(devlink_port->devlink))
-		return;
+	ASSERT_DEVLINK_PORT_NOT_REGISTERED(devlink_port);
+
 	ret = __devlink_port_attrs_set(devlink_port,
 				       DEVLINK_PORT_FLAVOUR_PCI_PF);
 	if (ret)
@@ -10123,8 +10169,8 @@ void devlink_port_attrs_pci_vf_set(struct devlink_port *devlink_port, u32 contro
 	struct devlink_port_attrs *attrs = &devlink_port->attrs;
 	int ret;
 
-	if (WARN_ON(devlink_port->devlink))
-		return;
+	ASSERT_DEVLINK_PORT_NOT_REGISTERED(devlink_port);
+
 	ret = __devlink_port_attrs_set(devlink_port,
 				       DEVLINK_PORT_FLAVOUR_PCI_VF);
 	if (ret)
@@ -10151,8 +10197,8 @@ void devlink_port_attrs_pci_sf_set(struct devlink_port *devlink_port, u32 contro
 	struct devlink_port_attrs *attrs = &devlink_port->attrs;
 	int ret;
 
-	if (WARN_ON(devlink_port->devlink))
-		return;
+	ASSERT_DEVLINK_PORT_NOT_REGISTERED(devlink_port);
+
 	ret = __devlink_port_attrs_set(devlink_port,
 				       DEVLINK_PORT_FLAVOUR_PCI_SF);
 	if (ret)
@@ -10267,8 +10313,8 @@ EXPORT_SYMBOL_GPL(devl_rate_nodes_destroy);
 void devlink_port_linecard_set(struct devlink_port *devlink_port,
 			       struct devlink_linecard *linecard)
 {
-	if (WARN_ON(devlink_port->devlink))
-		return;
+	ASSERT_DEVLINK_PORT_NOT_REGISTERED(devlink_port);
+
 	devlink_port->linecard = linecard;
 }
 EXPORT_SYMBOL_GPL(devlink_port_linecard_set);
@@ -11339,6 +11385,8 @@ devlink_port_region_create(struct devlink_port *port,
 	struct devlink_region *region;
 	int err = 0;
 
+	ASSERT_DEVLINK_PORT_INITIALIZED(port);
+
 	if (WARN_ON(!ops) || WARN_ON(!ops->destructor))
 		return ERR_PTR(-EINVAL);