[openwrt/staging/blocktrron.git] /

From 9c7aab7ebe1ac6b5519e3b05a9c771df4c7e7aaf Mon Sep 17 00:00:00 2001
From: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Date: Thu, 29 Aug 2024 12:55:39 +0200
Subject: [PATCH] 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: Hans Verkuil <hverkuil-cisco@xs4all.nl>
---
 drivers/media/mc/mc-device.c  | 30 ++++++++++++++++++++++++++++++
 drivers/media/mc/mc-devnode.c |  5 +++++
 drivers/media/mc/mc-request.c |  6 ++++++
 include/media/media-device.h  |  9 +++++++++
 include/media/media-devnode.h |  4 ++++
 include/media/media-request.h |  2 ++
 6 files changed, 56 insertions(+)

--- a/drivers/media/mc/mc-device.c
+++ b/drivers/media/mc/mc-device.c
@@ -679,6 +679,23 @@ void media_device_unregister_entity(stru
 }
 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_devi
                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
 
        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 medi
 
        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_*() */
--- a/drivers/media/mc/mc-devnode.c
+++ b/drivers/media/mc/mc-devnode.c
@@ -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)
 {
@@ -236,6 +239,7 @@ int __must_check media_devnode_register(
        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 */
@@ -313,6 +317,7 @@ static int __init media_devnode_init(voi
 
 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);
 }
--- a/drivers/media/mc/mc-request.c
+++ b/drivers/media/mc/mc-request.c
@@ -75,6 +75,7 @@ static void media_request_release(struct
                mdev->ops->req_free(req);
        else
                kfree(req);
+       atomic_dec(&mdev->num_requests);
 }
 
 void media_request_put(struct media_request *req)
@@ -332,6 +333,7 @@ int media_request_alloc(struct media_dev
 
        snprintf(req->debug_str, sizeof(req->debug_str), "%u:%d",
                 atomic_inc_return(&mdev->request_id), fd);
+       atomic_inc(&mdev->num_requests);
        dev_dbg(mdev->dev, "request: allocated %s\n", req->debug_str);
 
        fd_install(fd, filp);
@@ -355,10 +357,12 @@ static void media_request_object_release
        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 *
@@ -423,6 +427,7 @@ int media_request_object_bind(struct med
        obj->req = req;
        obj->ops = ops;
        obj->priv = priv;
+       obj->mdev = req->mdev;
 
        if (is_buffer)
                list_add_tail(&obj->list, &req->objects);
@@ -430,6 +435,7 @@ int media_request_object_bind(struct med
                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);
--- a/include/media/media-device.h
+++ b/include/media/media-device.h
@@ -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;
 };
 
--- a/include/media/media-devnode.h
+++ b/include/media/media-devnode.h
@@ -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
--- a/include/media/media-request.h
+++ b/include/media/media-request.h
@@ -290,6 +290,7 @@ struct media_request_object_ops {
  * struct media_request_object - An opaque object that belongs to a media
  *                              request
  *
+ * @mdev: Media device this object belongs to
  * @ops: object's operations
  * @priv: object's priv pointer
  * @req: the request this object belongs to (can be NULL)
@@ -301,6 +302,7 @@ struct media_request_object_ops {
  * another struct that contains the actual data for this request object.
  */
 struct media_request_object {
+       struct media_device *mdev;
        const struct media_request_object_ops *ops;
        void *priv;
        struct media_request *req;