net: dsa: stop exposing tag proto module helpers to the world

The DSA tagging protocol driver macros are in the public include/net/dsa.h
probably because that's also where the DSA_TAG_PROTO_*_VALUE macros are
(MODULE_ALIAS_DSA_TAG_DRIVER hinges on those macro definitions).

But there is no reason to expose these helpers to <net/dsa.h>. That
header is shared between switch drivers (drivers/net/dsa/), tagging
protocol drivers (net/dsa/tag_*.c), the DSA core (net/dsa/ sans tag_*.c),
and the rest of the world (DSA master drivers, network stack, etc).
Too much exposure.

On the other hand, net/dsa/dsa_priv.h is included only by the DSA core
and by DSA tagging protocol drivers (or IOW, "friend" modules). Also a
bit too much exposure - I've contemplated creating a new header which is
only included by tagging protocol drivers, but completely separating a
new dsa_tag_proto.h from dsa_priv.h is not immediately trivial - for
example dsa_slave_to_port() is used both from the fast path and from the
control path.

So for now, move these definitions to dsa_priv.h which at least hides
them from the world.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Michael Walle <michael@walle.cc>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 70 insertions, 0 deletions

diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h
index 71e9707d11d4..23d2dfdbc1ab 100644
--- a/net/dsa/dsa_priv.h
+++ b/net/dsa/dsa_priv.h
@@ -17,6 +17,76 @@
 
 #define DSA_MAX_NUM_OFFLOADING_BRIDGES		BITS_PER_LONG
 
+#define DSA_TAG_DRIVER_ALIAS "dsa_tag-"
+#define MODULE_ALIAS_DSA_TAG_DRIVER(__proto)				\
+	MODULE_ALIAS(DSA_TAG_DRIVER_ALIAS __stringify(__proto##_VALUE))
+
+struct dsa_tag_driver {
+	const struct dsa_device_ops *ops;
+	struct list_head list;
+	struct module *owner;
+};
+
+void dsa_tag_drivers_register(struct dsa_tag_driver *dsa_tag_driver_array[],
+			      unsigned int count,
+			      struct module *owner);
+void dsa_tag_drivers_unregister(struct dsa_tag_driver *dsa_tag_driver_array[],
+				unsigned int count);
+
+#define dsa_tag_driver_module_drivers(__dsa_tag_drivers_array, __count)	\
+static int __init dsa_tag_driver_module_init(void)			\
+{									\
+	dsa_tag_drivers_register(__dsa_tag_drivers_array, __count,	\
+				 THIS_MODULE);				\
+	return 0;							\
+}									\
+module_init(dsa_tag_driver_module_init);				\
+									\
+static void __exit dsa_tag_driver_module_exit(void)			\
+{									\
+	dsa_tag_drivers_unregister(__dsa_tag_drivers_array, __count);	\
+}									\
+module_exit(dsa_tag_driver_module_exit)
+
+/**
+ * module_dsa_tag_drivers() - Helper macro for registering DSA tag
+ * drivers
+ * @__ops_array: Array of tag driver structures
+ *
+ * Helper macro for DSA tag drivers which do not do anything special
+ * in module init/exit. Each module may only use this macro once, and
+ * calling it replaces module_init() and module_exit().
+ */
+#define module_dsa_tag_drivers(__ops_array)				\
+dsa_tag_driver_module_drivers(__ops_array, ARRAY_SIZE(__ops_array))
+
+#define DSA_TAG_DRIVER_NAME(__ops) dsa_tag_driver ## _ ## __ops
+
+/* Create a static structure we can build a linked list of dsa_tag
+ * drivers
+ */
+#define DSA_TAG_DRIVER(__ops)						\
+static struct dsa_tag_driver DSA_TAG_DRIVER_NAME(__ops) = {		\
+	.ops = &__ops,							\
+}
+
+/**
+ * module_dsa_tag_driver() - Helper macro for registering a single DSA tag
+ * driver
+ * @__ops: Single tag driver structures
+ *
+ * Helper macro for DSA tag drivers which do not do anything special
+ * in module init/exit. Each module may only use this macro once, and
+ * calling it replaces module_init() and module_exit().
+ */
+#define module_dsa_tag_driver(__ops)					\
+DSA_TAG_DRIVER(__ops);							\
+									\
+static struct dsa_tag_driver *dsa_tag_driver_array[] =	{		\
+	&DSA_TAG_DRIVER_NAME(__ops)					\
+};									\
+module_dsa_tag_drivers(dsa_tag_driver_array)
+
 enum {
 	DSA_NOTIFIER_AGEING_TIME,
 	DSA_NOTIFIER_BRIDGE_JOIN,