[PATCH] drm: use ida to allocate connector ids

[Ilia Mirkin]

This makes it so that reloading a module does not cause all the
connector ids to change, which are user-visible and sometimes used
for configuration.

Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
---

Only mild testing... reloaded nouveau a few times, all the connectors
kept their original ids.

 drivers/gpu/drm/drm_crtc.c | 61 +++++++++++++++++++++++++++++++---------------
 drivers/gpu/drm/drm_drv.c  |  2 ++
 include/drm/drm_crtc.h     |  2 ++
 3 files changed, 46 insertions(+), 19 deletions(-)

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index fc83bb9..fff238f 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -186,29 +186,29 @@ static const struct drm_prop_enum_list drm_dirty_info_enum_list[] = {
 struct drm_conn_prop_enum_list {
 	int type;
 	const char *name;
-	int count;
+	struct ida count;
 };
 
 /*
  * Connector and encoder types.
  */
 static struct drm_conn_prop_enum_list drm_connector_enum_list[] =
-{	{ DRM_MODE_CONNECTOR_Unknown, "Unknown", 0 },
-	{ DRM_MODE_CONNECTOR_VGA, "VGA", 0 },
-	{ DRM_MODE_CONNECTOR_DVII, "DVI-I", 0 },
-	{ DRM_MODE_CONNECTOR_DVID, "DVI-D", 0 },
-	{ DRM_MODE_CONNECTOR_DVIA, "DVI-A", 0 },
-	{ DRM_MODE_CONNECTOR_Composite, "Composite", 0 },
-	{ DRM_MODE_CONNECTOR_SVIDEO, "SVIDEO", 0 },
-	{ DRM_MODE_CONNECTOR_LVDS, "LVDS", 0 },
-	{ DRM_MODE_CONNECTOR_Component, "Component", 0 },
-	{ DRM_MODE_CONNECTOR_9PinDIN, "DIN", 0 },
-	{ DRM_MODE_CONNECTOR_DisplayPort, "DP", 0 },
-	{ DRM_MODE_CONNECTOR_HDMIA, "HDMI-A", 0 },
-	{ DRM_MODE_CONNECTOR_HDMIB, "HDMI-B", 0 },
-	{ DRM_MODE_CONNECTOR_TV, "TV", 0 },
-	{ DRM_MODE_CONNECTOR_eDP, "eDP", 0 },
-	{ DRM_MODE_CONNECTOR_VIRTUAL, "Virtual", 0},
+{	{ DRM_MODE_CONNECTOR_Unknown, "Unknown" },
+	{ DRM_MODE_CONNECTOR_VGA, "VGA" },
+	{ DRM_MODE_CONNECTOR_DVII, "DVI-I" },
+	{ DRM_MODE_CONNECTOR_DVID, "DVI-D" },
+	{ DRM_MODE_CONNECTOR_DVIA, "DVI-A" },
+	{ DRM_MODE_CONNECTOR_Composite, "Composite" },
+	{ DRM_MODE_CONNECTOR_SVIDEO, "SVIDEO" },
+	{ DRM_MODE_CONNECTOR_LVDS, "LVDS" },
+	{ DRM_MODE_CONNECTOR_Component, "Component" },
+	{ DRM_MODE_CONNECTOR_9PinDIN, "DIN" },
+	{ DRM_MODE_CONNECTOR_DisplayPort, "DP" },
+	{ DRM_MODE_CONNECTOR_HDMIA, "HDMI-A" },
+	{ DRM_MODE_CONNECTOR_HDMIB, "HDMI-B" },
+	{ DRM_MODE_CONNECTOR_TV, "TV" },
+	{ DRM_MODE_CONNECTOR_eDP, "eDP" },
+	{ DRM_MODE_CONNECTOR_VIRTUAL, "Virtual" },
 };
 
 static const struct drm_prop_enum_list drm_encoder_enum_list[] =
@@ -220,6 +220,22 @@ static const struct drm_prop_enum_list drm_encoder_enum_list[] =
 	{ DRM_MODE_ENCODER_VIRTUAL, "Virtual" },
 };
 
+void drm_connector_ida_init(void)
+{
+	int i;
+
+	for (i = 0; i <= ARRAY_SIZE(drm_connector_enum_list); i++)
+		ida_init(&drm_connector_enum_list[i].count);
+}
+
+void drm_connector_ida_destroy(void)
+{
+	int i;
+
+	for (i = 0; i <= ARRAY_SIZE(drm_connector_enum_list); i++)
+		ida_destroy(&drm_connector_enum_list[i].count);
+}
+
 const char *drm_get_encoder_name(const struct drm_encoder *encoder)
 {
 	static char buf[32];
@@ -711,6 +727,9 @@ int drm_connector_init(struct drm_device *dev,
 		       int connector_type)
 {
 	int ret;
+	struct ida *count = &drm_connector_enum_list[connector_type].count;
+
+	ida_pre_get(count, GFP_KERNEL);
 
 	drm_modeset_lock_all(dev);
 
@@ -722,8 +741,9 @@ int drm_connector_init(struct drm_device *dev,
 	connector->dev = dev;
 	connector->funcs = funcs;
 	connector->connector_type = connector_type;
-	connector->connector_type_id =
-		++drm_connector_enum_list[connector_type].count; /* TODO */
+	ret = ida_get_new_above(count, 1, &connector->connector_type_id);
+	if (ret)
+		goto out;
 	INIT_LIST_HEAD(&connector->probed_modes);
 	INIT_LIST_HEAD(&connector->modes);
 	connector->edid_blob_ptr = NULL;
@@ -764,6 +784,9 @@ void drm_connector_cleanup(struct drm_connector *connector)
 	list_for_each_entry_safe(mode, t, &connector->modes, head)
 		drm_mode_remove(connector, mode);
 
+	ida_remove(&drm_connector_enum_list[connector->connector_type].count,
+		   connector->connector_type_id);
+
 	drm_mode_object_put(dev, &connector->base);
 	list_del(&connector->head);
 	dev->mode_config.num_connector--;
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 99fcd7c..00597a1 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -251,6 +251,7 @@ static int __init drm_core_init(void)
 	int ret = -ENOMEM;
 
 	drm_global_init();
+	drm_connector_ida_init();
 	idr_init(&drm_minors_idr);
 
 	if (register_chrdev(DRM_MAJOR, "drm", &drm_stub_fops))
@@ -298,6 +299,7 @@ static void __exit drm_core_exit(void)
 
 	unregister_chrdev(DRM_MAJOR, "drm");
 
+	drm_connector_ida_destroy();
 	idr_destroy(&drm_minors_idr);
 }
 
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index fa12a2f..effee9d 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -869,6 +869,8 @@ extern int drm_crtc_init(struct drm_device *dev,
 			 const struct drm_crtc_funcs *funcs);
 extern void drm_crtc_cleanup(struct drm_crtc *crtc);
 
+extern void drm_connector_ida_init(void);
+extern void drm_connector_ida_destroy(void);
 extern int drm_connector_init(struct drm_device *dev,
 			      struct drm_connector *connector,
 			      const struct drm_connector_funcs *funcs,
-- 
1.8.1.5