[PATCH] drm/drm_bridge: adjust bridge module's refcount
Jyri Sarha
jsarha at ti.com
Tue Nov 29 21:12:56 UTC 2016
Store the module that provides the bridge and adjust its refcount
accordingly. The bridge module unload should not be allowed while the
bridge is attached.
Signed-off-by: Jyri Sarha <jsarha at ti.com>
---
drivers/gpu/drm/drm_bridge.c | 15 ++++++++++++---
include/drm/drm_bridge.h | 11 ++++++++++-
2 files changed, 22 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
index 0ee052b..36d427b 100644
--- a/drivers/gpu/drm/drm_bridge.c
+++ b/drivers/gpu/drm/drm_bridge.c
@@ -61,22 +61,26 @@
static LIST_HEAD(bridge_list);
/**
- * drm_bridge_add - add the given bridge to the global bridge list
+ * __drm_bridge_add - add the given bridge to the global bridge list
*
* @bridge: bridge control structure
+ * @module: module that provides this bridge
*
* RETURNS:
* Unconditionally returns Zero.
*/
-int drm_bridge_add(struct drm_bridge *bridge)
+int __drm_bridge_add(struct drm_bridge *bridge, struct module *module)
{
+#ifdef MODULE
+ bridge->module = module;
+#endif
mutex_lock(&bridge_lock);
list_add_tail(&bridge->list, &bridge_list);
mutex_unlock(&bridge_lock);
return 0;
}
-EXPORT_SYMBOL(drm_bridge_add);
+EXPORT_SYMBOL(__drm_bridge_add);
/**
* drm_bridge_remove - remove the given bridge from the global bridge list
@@ -114,6 +118,9 @@ int drm_bridge_attach(struct drm_device *dev, struct drm_bridge *bridge)
if (bridge->dev)
return -EBUSY;
+ if (!try_module_get(bridge->module))
+ return -ENOENT;
+
bridge->dev = dev;
if (bridge->funcs->attach)
@@ -144,6 +151,8 @@ void drm_bridge_detach(struct drm_bridge *bridge)
if (bridge->funcs->detach)
bridge->funcs->detach(bridge);
+ module_put(bridge->module);
+
bridge->dev = NULL;
}
EXPORT_SYMBOL(drm_bridge_detach);
diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
index 530a1d6..d60d5d2 100644
--- a/include/drm/drm_bridge.h
+++ b/include/drm/drm_bridge.h
@@ -25,6 +25,7 @@
#include <linux/list.h>
#include <linux/ctype.h>
+#include <linux/module.h>
#include <drm/drm_mode_object.h>
#include <drm/drm_modes.h>
@@ -192,13 +193,21 @@ struct drm_bridge {
#ifdef CONFIG_OF
struct device_node *of_node;
#endif
+#ifdef MODULE
+ struct module *module;
+#endif
struct list_head list;
const struct drm_bridge_funcs *funcs;
void *driver_private;
};
-int drm_bridge_add(struct drm_bridge *bridge);
+int __drm_bridge_add(struct drm_bridge *bridge, struct module *module);
+#ifdef MODULE
+#define drm_bridge_add(bridge) __drm_bridge_add(bridge, THIS_MODULE)
+#else
+#define drm_bridge_add(bridge) __drm_bridge_add(bridge, NULL)
+#endif
void drm_bridge_remove(struct drm_bridge *bridge);
struct drm_bridge *of_drm_find_bridge(struct device_node *np);
int drm_bridge_attach(struct drm_device *dev, struct drm_bridge *bridge);
--
1.9.1
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