From: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
The module ownership refcounting was done in media_entity_get/put,
but that was very confusing and it did not work either in case an
application had a v4l-subdevX device open and the module was
unbound. When the v4l-subdevX device was closed the media_entity_put
was never called and the module refcount was left one too high, making
it impossible to unload it.
Since v4l2-subdev.c was the only place where media_entity_get/put was
called, just move the functionality to v4l2-subdev.c and drop those
confusing entity functions.
Store the module in subdev_fh so module_put no longer depends on
the media_entity struct.
Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
---
drivers/media/media-entity.c | 28 ---------------------------
drivers/media/v4l2-core/v4l2-subdev.c | 22 +++++++++------------
include/media/media-entity.h | 24 -----------------------
include/media/v4l2-subdev.h | 1 +
4 files changed, 10 insertions(+), 65 deletions(-)
diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c
index 7b2a2cc95530..257f20d2fb8a 100644
--- a/drivers/media/media-entity.c
+++ b/drivers/media/media-entity.c
@@ -17,7 +17,6 @@
*/
#include <linux/bitmap.h>
-#include <linux/module.h>
#include <linux/property.h>
#include <linux/slab.h>
#include <media/media-entity.h>
@@ -588,33 +587,6 @@ void media_pipeline_stop(struct media_entity *entity)
}
EXPORT_SYMBOL_GPL(media_pipeline_stop);
-/* -----------------------------------------------------------------------------
- * Module use count
- */
-
-struct media_entity *media_entity_get(struct media_entity *entity)
-{
- if (entity == NULL)
- return NULL;
-
- if (entity->graph_obj.mdev->dev &&
- !try_module_get(entity->graph_obj.mdev->dev->driver->owner))
- return NULL;
-
- return entity;
-}
-EXPORT_SYMBOL_GPL(media_entity_get);
-
-void media_entity_put(struct media_entity *entity)
-{
- if (entity == NULL)
- return;
-
- if (entity->graph_obj.mdev->dev)
- module_put(entity->graph_obj.mdev->dev->driver->owner);
-}
-EXPORT_SYMBOL_GPL(media_entity_put);
-
/* -----------------------------------------------------------------------------
* Links management
*/
diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
index f5f0d71ec745..d75815ab0d7b 100644
--- a/drivers/media/v4l2-core/v4l2-subdev.c
+++ b/drivers/media/v4l2-core/v4l2-subdev.c
@@ -18,6 +18,7 @@
#include <linux/ioctl.h>
#include <linux/mm.h>
+#include <linux/module.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/videodev2.h>
@@ -54,9 +55,6 @@ static int subdev_open(struct file *file)
struct video_device *vdev = video_devdata(file);
struct v4l2_subdev *sd = vdev_to_v4l2_subdev(vdev);
struct v4l2_subdev_fh *subdev_fh;
-#if defined(CONFIG_MEDIA_CONTROLLER)
- struct media_entity *entity = NULL;
-#endif
int ret;
subdev_fh = kzalloc(sizeof(*subdev_fh), GFP_KERNEL);
@@ -73,12 +71,15 @@ static int subdev_open(struct file *file)
v4l2_fh_add(&subdev_fh->vfh);
file->private_data = &subdev_fh->vfh;
#if defined(CONFIG_MEDIA_CONTROLLER)
- if (sd->v4l2_dev->mdev) {
- entity = media_entity_get(&sd->entity);
- if (!entity) {
+ if (sd->v4l2_dev->mdev && sd->entity.graph_obj.mdev->dev) {
+ struct module *owner;
+
+ owner = sd->entity.graph_obj.mdev->dev->driver->owner;
+ if (!try_module_get(owner)) {
ret = -EBUSY;
goto err;
}
+ subdev_fh->owner = owner;
}
#endif
@@ -91,9 +92,7 @@ static int subdev_open(struct file *file)
return 0;
err:
-#if defined(CONFIG_MEDIA_CONTROLLER)
- media_entity_put(entity);
-#endif
+ module_put(subdev_fh->owner);
v4l2_fh_del(&subdev_fh->vfh);
v4l2_fh_exit(&subdev_fh->vfh);
subdev_fh_free(subdev_fh);
@@ -111,10 +110,7 @@ static int subdev_close(struct file *file)
if (sd->internal_ops && sd->internal_ops->close)
sd->internal_ops->close(sd, subdev_fh);
-#if defined(CONFIG_MEDIA_CONTROLLER)
- if (sd->v4l2_dev->mdev)
- media_entity_put(&sd->entity);
-#endif
+ module_put(subdev_fh->owner);
v4l2_fh_del(vfh);
v4l2_fh_exit(vfh);
subdev_fh_free(subdev_fh);
diff --git a/include/media/media-entity.h b/include/media/media-entity.h
index e5f6960d92f6..3cbad42e3693 100644
--- a/include/media/media-entity.h
+++ b/include/media/media-entity.h
@@ -864,19 +864,6 @@ struct media_link *media_entity_find_link(struct media_pad *source,
*/
struct media_pad *media_entity_remote_pad(const struct media_pad *pad);
-/**
- * media_entity_get - Get a reference to the parent module
- *
- * @entity: The entity
- *
- * Get a reference to the parent media device module.
- *
- * The function will return immediately if @entity is %NULL.
- *
- * Return: returns a pointer to the entity on success or %NULL on failure.
- */
-struct media_entity *media_entity_get(struct media_entity *entity);
-
/**
* media_entity_get_fwnode_pad - Get pad number from fwnode
*
@@ -916,17 +903,6 @@ __must_check int media_graph_walk_init(
*/
void media_graph_walk_cleanup(struct media_graph *graph);
-/**
- * media_entity_put - Release the reference to the parent module
- *
- * @entity: The entity
- *
- * Release the reference count acquired by media_entity_get().
- *
- * The function will return immediately if @entity is %NULL.
- */
-void media_entity_put(struct media_entity *entity);
-
/**
* media_graph_walk_start - Start walking the media graph at a
* given entity
diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
index 2f2d1c8947e6..33ba56f3dc1f 100644
--- a/include/media/v4l2-subdev.h
+++ b/include/media/v4l2-subdev.h
@@ -905,6 +905,7 @@ struct v4l2_subdev {
*/
struct v4l2_subdev_fh {
struct v4l2_fh vfh;
+ struct module *owner;
#if defined(CONFIG_VIDEO_V4L2_SUBDEV_API)
struct v4l2_subdev_pad_config *pad;
#endif
--
2.20.1
