On 20/12/2023 11:37, Sakari Ailus wrote:
> From: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
>
> The media devnode core associates devnodes with files by storing the
> devnode pointer in the file structure private_data field. In order to
> allow tracking of per-file-handle data introduce a new media devnode
> file handle structure that stores the devnode pointer, and store a
> pointer to that structure in the file private_data field.
>
> Users of the media devnode code (the only existing user being
> media_device) are responsible for managing their own subclass of the
> media_devnode_fh structure.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
>
> Prepare struct media_device_fh to be used for maintaining file handle list
> to avoid shuffling things here and there right after.
>
> Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
Acked-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
> ---
> drivers/media/mc/mc-device.c | 14 +++++++++++++-
> drivers/media/mc/mc-devnode.c | 20 +++++++++-----------
> include/media/media-device.h | 7 +++++++
> include/media/media-devnode.h | 18 +++++++++++++++++-
> include/media/media-fh.h | 32 ++++++++++++++++++++++++++++++++
> 5 files changed, 78 insertions(+), 13 deletions(-)
> create mode 100644 include/media/media-fh.h
>
> diff --git a/drivers/media/mc/mc-device.c b/drivers/media/mc/mc-device.c
> index 10426c2796b6..67a39cb63f89 100644
> --- a/drivers/media/mc/mc-device.c
> +++ b/drivers/media/mc/mc-device.c
> @@ -22,6 +22,7 @@
> #include <media/media-device.h>
> #include <media/media-devnode.h>
> #include <media/media-entity.h>
> +#include <media/media-fh.h>
> #include <media/media-request.h>
>
> #ifdef CONFIG_MEDIA_CONTROLLER
> @@ -35,7 +36,6 @@
> #define MEDIA_ENT_SUBTYPE_MASK 0x0000ffff
> #define MEDIA_ENT_T_DEVNODE_UNKNOWN (MEDIA_ENT_F_OLD_BASE | \
> MEDIA_ENT_SUBTYPE_MASK)
> -
> /* -----------------------------------------------------------------------------
> * Userspace API
> */
> @@ -47,11 +47,23 @@ static inline void __user *media_get_uptr(__u64 arg)
>
> static int media_device_open(struct file *filp)
> {
> + struct media_device_fh *fh;
> +
> + fh = kzalloc(sizeof(*fh), GFP_KERNEL);
> + if (!fh)
> + return -ENOMEM;
> +
> + filp->private_data = &fh->fh;
> +
> return 0;
> }
>
> static int media_device_close(struct file *filp)
> {
> + struct media_device_fh *fh = media_device_fh(filp);
> +
> + kfree(fh);
> +
> return 0;
> }
>
> diff --git a/drivers/media/mc/mc-devnode.c b/drivers/media/mc/mc-devnode.c
> index 4ea05e42dafb..04d376015526 100644
> --- a/drivers/media/mc/mc-devnode.c
> +++ b/drivers/media/mc/mc-devnode.c
> @@ -150,6 +150,7 @@ static long media_compat_ioctl(struct file *filp, unsigned int cmd,
> static int media_open(struct inode *inode, struct file *filp)
> {
> struct media_devnode *devnode;
> + struct media_devnode_fh *fh;
> int ret;
>
> /* Check if the media device is available. This needs to be done with
> @@ -170,17 +171,15 @@ static int media_open(struct inode *inode, struct file *filp)
> get_device(&devnode->dev);
> mutex_unlock(&media_devnode_lock);
>
> - filp->private_data = devnode;
> -
> - if (devnode->fops->open) {
> - ret = devnode->fops->open(filp);
> - if (ret) {
> - put_device(&devnode->dev);
> - filp->private_data = NULL;
> - return ret;
> - }
> + ret = devnode->fops->open(filp);
> + if (ret) {
> + put_device(&devnode->dev);
> + return ret;
> }
>
> + fh = filp->private_data;
> + fh->devnode = devnode;
> +
> return 0;
> }
>
> @@ -189,8 +188,7 @@ static int media_release(struct inode *inode, struct file *filp)
> {
> struct media_devnode *devnode = media_devnode_data(filp);
>
> - if (devnode->fops->release)
> - devnode->fops->release(filp);
> + devnode->fops->release(filp);
>
> filp->private_data = NULL;
>
> diff --git a/include/media/media-device.h b/include/media/media-device.h
> index 98e1892f1b51..83b8ea44463d 100644
> --- a/include/media/media-device.h
> +++ b/include/media/media-device.h
> @@ -110,6 +110,10 @@ struct media_device_ops {
> * other operations that stop or start streaming.
> * @request_id: Used to generate unique request IDs
> *
> + * @fh_list: List of file handles in the media device
> + * (struct media_device_fh.mdev_list).
> + * @fh_list_lock: Serialise access to fh_list list.
> + *
> * This structure represents an abstract high-level media device. It allows easy
> * access to entities and provides basic media device-level support. The
> * structure can be allocated directly or embedded in a larger structure.
> @@ -182,6 +186,9 @@ struct media_device {
>
> struct mutex req_queue_mutex;
> atomic_t request_id;
> +
> + struct list_head fh_list;
> + spinlock_t fh_list_lock;
> };
>
> /* We don't need to include usb.h here */
> diff --git a/include/media/media-devnode.h b/include/media/media-devnode.h
> index d050f54f252a..b0efdde4ffd8 100644
> --- a/include/media/media-devnode.h
> +++ b/include/media/media-devnode.h
> @@ -53,6 +53,20 @@ struct media_file_operations {
> int (*release) (struct file *);
> };
>
> +/**
> + * struct media_devnode_fh - Media device node file handle
> + * @devnode: pointer to the media device node
> + *
> + * This structure serves as a base for per-file-handle data storage. Media
> + * device node users embed media_devnode_fh in their custom file handle data
> + * structures and store the media_devnode_fh in the file private_data in order
> + * to let the media device node core locate the media_devnode corresponding to a
> + * file handle.
> + */
> +struct media_devnode_fh {
> + struct media_devnode *devnode;
> +};
> +
> /**
> * struct media_devnode - Media device node
> * @media_dev: pointer to struct &media_device
> @@ -137,7 +151,9 @@ void media_devnode_unregister(struct media_devnode *devnode);
> */
> static inline struct media_devnode *media_devnode_data(struct file *filp)
> {
> - return filp->private_data;
> + struct media_devnode_fh *fh = filp->private_data;
> +
> + return fh->devnode;
> }
>
> /**
> diff --git a/include/media/media-fh.h b/include/media/media-fh.h
> new file mode 100644
> index 000000000000..6f00744b81d6
> --- /dev/null
> +++ b/include/media/media-fh.h
> @@ -0,0 +1,32 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Media device file handle
> + *
> + * Copyright (C) 2019--2023 Intel Corporation
> + */
> +
> +#ifndef MEDIA_FH_H
> +#define MEDIA_FH_H
> +
> +#include <linux/list.h>
> +#include <linux/file.h>
> +
> +#include <media/media-devnode.h>
> +
> +/**
> + * struct media_device_fh - File handle specific information on MC
> + *
> + * @fh: The media device file handle
> + * @mdev_list: This file handle in media device's list of file handles
> + */
> +struct media_device_fh {
> + struct media_devnode_fh fh;
> + struct list_head mdev_list;
> +};
> +
> +static inline struct media_device_fh *media_device_fh(struct file *filp)
> +{
> + return container_of(filp->private_data, struct media_device_fh, fh);
> +}
> +
> +#endif /* MEDIA_FH_H */
