[PATCH 24/26] media: Maintain a list of open file handles in a media device

[Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>]

The list of file handles is needed to deliver media events as well as for
other purposes in the future.

Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
---
 drivers/media/mc/mc-device.c  | 23 ++++++++++++++++++++++-
 drivers/media/mc/mc-devnode.c |  2 +-
 include/media/media-devnode.h |  4 +++-
 3 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/drivers/media/mc/mc-device.c b/drivers/media/mc/mc-device.c
index 0419a7deccc3..3a1db5fdbba7 100644
--- a/drivers/media/mc/mc-device.c
+++ b/drivers/media/mc/mc-device.c
@@ -45,9 +45,11 @@ static inline void __user *media_get_uptr(__u64 arg)
 	return (void __user *)(uintptr_t)arg;
 }
 
-static int media_device_open(struct file *filp)
+static int media_device_open(struct media_devnode *devnode, struct file *filp)
 {
+	struct media_device *mdev = to_media_device(devnode);
 	struct media_device_fh *fh;
+	unsigned long flags;
 
 	fh = kzalloc(sizeof(*fh), GFP_KERNEL);
 	if (!fh)
@@ -55,12 +57,23 @@ static int media_device_open(struct file *filp)
 
 	filp->private_data = &fh->fh;
 
+	spin_lock_irqsave(&mdev->fh_list_lock, flags);
+	list_add(&fh->mdev_list, &mdev->fh_list);
+	spin_unlock_irqrestore(&mdev->fh_list_lock, flags);
+
 	return 0;
 }
 
 static int media_device_close(struct file *filp)
 {
+	struct media_devnode *devnode = media_devnode_data(filp);
+	struct media_device *mdev = to_media_device(devnode);
 	struct media_device_fh *fh = media_device_fh(filp);
+	unsigned long flags;
+
+	spin_lock_irqsave(&mdev->fh_list_lock, flags);
+	list_del(&fh->mdev_list);
+	spin_unlock_irqrestore(&mdev->fh_list_lock, flags);
 
 	kfree(fh);
 
@@ -773,11 +786,13 @@ void media_device_init(struct media_device *mdev)
 	INIT_LIST_HEAD(&mdev->pads);
 	INIT_LIST_HEAD(&mdev->links);
 	INIT_LIST_HEAD(&mdev->entity_notify);
+	INIT_LIST_HEAD(&mdev->fh_list);
 
 	mutex_init(&mdev->req_queue_mutex);
 	mutex_init(&mdev->graph_mutex);
 	ida_init(&mdev->entity_internal_idx);
 	atomic_set(&mdev->request_id, 0);
+	spin_lock_init(&mdev->fh_list_lock);
 
 	/*
 	 * Set the release callback to the media device if we have one
@@ -836,6 +851,8 @@ EXPORT_SYMBOL_GPL(__media_device_register);
 
 void media_device_unregister(struct media_device *mdev)
 {
+	unsigned long flags;
+
 	if (mdev == NULL)
 		return;
 
@@ -846,6 +863,10 @@ void media_device_unregister(struct media_device *mdev)
 	}
 	mutex_unlock(&mdev->graph_mutex);
 
+	spin_lock_irqsave(&mdev->fh_list_lock, flags);
+	list_del_init(&mdev->fh_list);
+	spin_unlock_irqrestore(&mdev->fh_list_lock, flags);
+
 	device_remove_file(&mdev->devnode.dev, &dev_attr_model);
 	dev_dbg(mdev->dev, "Media device unregistering\n");
 	media_devnode_unregister(&mdev->devnode);
diff --git a/drivers/media/mc/mc-devnode.c b/drivers/media/mc/mc-devnode.c
index cb07b3a87bfb..760314dd22e1 100644
--- a/drivers/media/mc/mc-devnode.c
+++ b/drivers/media/mc/mc-devnode.c
@@ -161,7 +161,7 @@ static int media_open(struct inode *inode, struct file *filp)
 	get_device(&devnode->dev);
 	mutex_unlock(&media_devnode_lock);
 
-	ret = devnode->fops->open(filp);
+	ret = devnode->fops->open(devnode, filp);
 	if (ret) {
 		put_device(&devnode->dev);
 		return ret;
diff --git a/include/media/media-devnode.h b/include/media/media-devnode.h
index f22b3835702e..d21c13829072 100644
--- a/include/media/media-devnode.h
+++ b/include/media/media-devnode.h
@@ -21,6 +21,8 @@
 #include <linux/device.h>
 #include <linux/cdev.h>
 
+struct media_devnode;
+
 /*
  * Flag to mark the media_devnode struct as registered. Drivers must not touch
  * this flag directly, it will be set and cleared by media_devnode_register and
@@ -49,7 +51,7 @@ struct media_file_operations {
 	__poll_t (*poll) (struct file *, struct poll_table_struct *);
 	long (*ioctl) (struct file *, unsigned int, unsigned long);
 	long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
-	int (*open) (struct file *);
+	int (*open) (struct media_devnode *, struct file *);
 	int (*release) (struct file *);
 };
 
-- 
2.30.2