From 218bf10e39ed5fb22a48dee40bfd2bbcb91693ba Mon Sep 17 00:00:00 2001 From: Hans Verkuil Date: Fri, 1 Mar 2019 06:11:27 -0500 Subject: [PATCH] media: v4l2-subdev: handle module refcounting here 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 Reviewed-by: Laurent Pinchart Signed-off-by: Mauro Carvalho Chehab --- 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 | 2 ++ 4 files changed, 11 insertions(+), 65 deletions(-) diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c index 0b1cb3559140..dd859d7b235a 100644 --- a/drivers/media/media-entity.c +++ b/drivers/media/media-entity.c @@ -17,7 +17,6 @@ */ #include -#include #include #include #include @@ -587,33 +586,6 @@ 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 #include +#include #include #include #include @@ -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 e807aa96ed3b..a7fa5b80915a 100644 --- a/include/media/v4l2-subdev.h +++ b/include/media/v4l2-subdev.h @@ -910,9 +910,11 @@ struct v4l2_subdev { * * @vfh: pointer to &struct v4l2_fh * @pad: pointer to &struct v4l2_subdev_pad_config + * @owner: module pointer to the owner of this file handle */ 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