Commit de9f0c2a authored by Hans Verkuil's avatar Hans Verkuil
Browse files

media: mc: add debugfs node to keep track of requests



Keep track of the number of requests and request objects of a media
device. Helps to verify that all request-related memory is freed.

Signed-off-by: default avatarHans Verkuil <hverkuil+cisco@kernel.org>
Signed-off-by: default avatarNicolas Dufresne <nicolas.dufresne@collabora.com>
parent d14d93f9
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+30 −0
Original line number Diff line number Diff line
@@ -679,6 +679,23 @@ void media_device_unregister_entity(struct media_entity *entity)
}
EXPORT_SYMBOL_GPL(media_device_unregister_entity);

#ifdef CONFIG_DEBUG_FS
/*
 * Log the state of media requests. Very useful for debugging.
 */
static int media_device_requests(struct seq_file *file, void *priv)
{
	struct media_device *dev = dev_get_drvdata(file->private);

	seq_printf(file, "number of requests: %d\n",
		   atomic_read(&dev->num_requests));
	seq_printf(file, "number of request objects: %d\n",
		   atomic_read(&dev->num_request_objects));

	return 0;
}
#endif

void media_device_init(struct media_device *mdev)
{
	INIT_LIST_HEAD(&mdev->entities);
@@ -697,6 +714,9 @@ void media_device_init(struct media_device *mdev)
		media_set_bus_info(mdev->bus_info, sizeof(mdev->bus_info),
				   mdev->dev);

	atomic_set(&mdev->num_requests, 0);
	atomic_set(&mdev->num_request_objects, 0);

	dev_dbg(mdev->dev, "Media device initialized\n");
}
EXPORT_SYMBOL_GPL(media_device_init);
@@ -748,6 +768,15 @@ int __must_check __media_device_register(struct media_device *mdev,

	dev_dbg(mdev->dev, "Media device registered\n");

#ifdef CONFIG_DEBUG_FS
	if (!media_debugfs_root)
		media_debugfs_root = debugfs_create_dir("media", NULL);
	mdev->media_dir = debugfs_create_dir(dev_name(&devnode->dev),
					     media_debugfs_root);
	debugfs_create_devm_seqfile(&devnode->dev, "requests",
				    mdev->media_dir, media_device_requests);
#endif

	return 0;
}
EXPORT_SYMBOL_GPL(__media_device_register);
@@ -824,6 +853,7 @@ void media_device_unregister(struct media_device *mdev)

	dev_dbg(mdev->dev, "Media device unregistered\n");

	debugfs_remove_recursive(mdev->media_dir);
	device_remove_file(&mdev->devnode->dev, &dev_attr_model);
	media_devnode_unregister(mdev->devnode);
	/* devnode free is handled in media_devnode_*() */
+5 −0
Original line number Diff line number Diff line
@@ -45,6 +45,9 @@ static dev_t media_dev_t;
static DEFINE_MUTEX(media_devnode_lock);
static DECLARE_BITMAP(media_devnode_nums, MEDIA_NUM_DEVICES);

/* debugfs */
struct dentry *media_debugfs_root;

/* Called when the last user of the media device exits. */
static void media_devnode_release(struct device *cd)
{
@@ -231,6 +234,7 @@ int __must_check media_devnode_register(struct media_device *mdev,
	if (devnode->parent)
		devnode->dev.parent = devnode->parent;
	dev_set_name(&devnode->dev, "media%d", devnode->minor);
	dev_set_drvdata(&devnode->dev, mdev);
	device_initialize(&devnode->dev);

	/* Part 2: Initialize the character device */
@@ -309,6 +313,7 @@ static int __init media_devnode_init(void)

static void __exit media_devnode_exit(void)
{
	debugfs_remove_recursive(media_debugfs_root);
	bus_unregister(&media_bus_type);
	unregister_chrdev_region(media_dev_t, MEDIA_NUM_DEVICES);
}
+6 −0
Original line number Diff line number Diff line
@@ -75,6 +75,7 @@ static void media_request_release(struct kref *kref)
		mdev->ops->req_free(req);
	else
		kfree(req);
	atomic_dec(&mdev->num_requests);
}

void media_request_put(struct media_request *req)
@@ -321,6 +322,7 @@ int media_request_alloc(struct media_device *mdev, int *alloc_fd)

	snprintf(req->debug_str, sizeof(req->debug_str), "%u:%d",
		 atomic_inc_return(&mdev->request_id), *alloc_fd);
	atomic_inc(&mdev->num_requests);
	dev_dbg(mdev->dev, "request: allocated %s\n", req->debug_str);

	return 0;
@@ -339,10 +341,12 @@ static void media_request_object_release(struct kref *kref)
	struct media_request_object *obj =
		container_of(kref, struct media_request_object, kref);
	struct media_request *req = obj->req;
	struct media_device *mdev = obj->mdev;

	if (WARN_ON(req))
		media_request_object_unbind(obj);
	obj->ops->release(obj);
	atomic_dec(&mdev->num_request_objects);
}

struct media_request_object *
@@ -407,6 +411,7 @@ int media_request_object_bind(struct media_request *req,
	obj->req = req;
	obj->ops = ops;
	obj->priv = priv;
	obj->mdev = req->mdev;

	if (is_buffer)
		list_add_tail(&obj->list, &req->objects);
@@ -414,6 +419,7 @@ int media_request_object_bind(struct media_request *req,
		list_add(&obj->list, &req->objects);
	req->num_incomplete_objects++;
	ret = 0;
	atomic_inc(&obj->mdev->num_request_objects);

unlock:
	spin_unlock_irqrestore(&req->lock, flags);
+9 −0
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@
#ifndef _MEDIA_DEVICE_H
#define _MEDIA_DEVICE_H

#include <linux/atomic.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/pci.h>
@@ -106,6 +107,9 @@ struct media_device_ops {
 * @ops:	Operation handler callbacks
 * @req_queue_mutex: Serialise the MEDIA_REQUEST_IOC_QUEUE ioctl w.r.t.
 *		     other operations that stop or start streaming.
 * @num_requests: number of associated requests
 * @num_request_objects: number of associated request objects
 * @media_dir:	DebugFS media directory
 * @request_id: Used to generate unique request IDs
 *
 * This structure represents an abstract high-level media device. It allows easy
@@ -179,6 +183,11 @@ struct media_device {
	const struct media_device_ops *ops;

	struct mutex req_queue_mutex;
	atomic_t num_requests;
	atomic_t num_request_objects;

	/* debugfs */
	struct dentry *media_dir;
	atomic_t request_id;
};

+4 −0
Original line number Diff line number Diff line
@@ -20,9 +20,13 @@
#include <linux/fs.h>
#include <linux/device.h>
#include <linux/cdev.h>
#include <linux/debugfs.h>

struct media_device;

/* debugfs top-level media directory */
extern struct dentry *media_debugfs_root;

/*
 * 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
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