Re: [PATCH v5 04/16] rpmsg: char: export eptdev create an destroy functions

Mathieu Poirier
2021-03-03T10:32:33Z

Good morning,

I have started to review this set - comments will be staggered over several
days.

On Fri, Feb 19, 2021 at 12:14:49PM +0100, Arnaud Pouliquen wrote:
> To prepare the split code related to the control and the endpoint
> devices in separate files:
> - suppress the dependency with the rpmsg_ctrldev struct,
> - rename and export the functions in rpmsg_char.h.
>
> Suggested-by: Mathieu Poirier <mathieu.poirier@linaro.org>
> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
> ---
> drivers/rpmsg/rpmsg_char.c | 22 ++++++++++------
> drivers/rpmsg/rpmsg_char.h | 51 ++++++++++++++++++++++++++++++++++++++
> 2 files changed, 66 insertions(+), 7 deletions(-)
> create mode 100644 drivers/rpmsg/rpmsg_char.h
>
> diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
> index 9e33b53bbf56..78a6d19fdf82 100644
> --- a/drivers/rpmsg/rpmsg_char.c
> +++ b/drivers/rpmsg/rpmsg_char.c
> @@ -1,5 +1,6 @@
> // SPDX-License-Identifier: GPL-2.0
> /*
> + * Copyright (C) 2021, STMicroelectronics
> * Copyright (c) 2016, Linaro Ltd.
> * Copyright (c) 2012, Michal Simek <monstr@monstr.eu>
> * Copyright (c) 2012, PetaLogix
> @@ -22,6 +23,7 @@
> #include <linux/uaccess.h>
> #include <uapi/linux/rpmsg.h>
>
> +#include "rpmsg_char.h"
> #include "rpmsg_internal.h"
>
> #define RPMSG_DEV_MAX (MINORMASK + 1)
> @@ -78,7 +80,7 @@ struct rpmsg_eptdev {
> wait_queue_head_t readq;
> };
>
> -static int rpmsg_eptdev_destroy(struct device *dev, void *data)
> +static int rpmsg_eptdev_destroy(struct device *dev)
> {
> struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev);
>
> @@ -277,7 +279,7 @@ static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd,
> if (cmd != RPMSG_DESTROY_EPT_IOCTL)
> return -EINVAL;
>
> - return rpmsg_eptdev_destroy(&eptdev->dev, NULL);
> + return rpmsg_eptdev_destroy(&eptdev->dev);
> }
>
> static const struct file_operations rpmsg_eptdev_fops = {
> @@ -336,10 +338,15 @@ static void rpmsg_eptdev_release_device(struct device *dev)
> kfree(eptdev);
> }
>
> -static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev,
> +int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data)
> +{
> + return rpmsg_eptdev_destroy(dev);
> +}
> +EXPORT_SYMBOL(rpmsg_chrdev_eptdev_destroy);

Below we have rpmsg_chrdev_create_eptdev() so it would make sense to have
rpmsg_chrdev_destroy_ept().

I would also rename rpmsg_eptdev_destroy() to rpmsg_chrdev_destroy_ept() and
export that symbol rather than introducing a function that only calls another
one. You did exactly that for rpmsg_chrdev_create_eptdev().

> +
> +int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent,
> struct rpmsg_channel_info chinfo)
> {
> - struct rpmsg_device *rpdev = ctrldev->rpdev;
> struct rpmsg_eptdev *eptdev;
> struct device *dev;
> int ret;
> @@ -359,7 +366,7 @@ static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev,
>
> device_initialize(dev);
> dev->class = rpmsg_class;
> - dev->parent = &ctrldev->dev;
> + dev->parent = parent;
> dev->groups = rpmsg_eptdev_groups;
> dev_set_drvdata(dev, eptdev);
>
> @@ -402,6 +409,7 @@ static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev,
>
> return ret;
> }
> +EXPORT_SYMBOL(rpmsg_chrdev_create_eptdev);
>
> static int rpmsg_ctrldev_open(struct inode *inode, struct file *filp)
> {
> @@ -441,7 +449,7 @@ static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd,
> chinfo.src = eptinfo.src;
> chinfo.dst = eptinfo.dst;
>
> - return rpmsg_eptdev_create(ctrldev, chinfo);
> + return rpmsg_chrdev_create_eptdev(ctrldev->rpdev, &ctrldev->dev, chinfo);

Not sure why we have to change the signature of rpmsg_eptdev_create() but I may
find an answer to that question later on in the patchset.

> };
>
> static const struct file_operations rpmsg_ctrldev_fops = {
> @@ -527,7 +535,7 @@ static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev)
> int ret;
>
> /* Destroy all endpoints */
> - ret = device_for_each_child(&ctrldev->dev, NULL, rpmsg_eptdev_destroy);
> + ret = device_for_each_child(&ctrldev->dev, NULL, rpmsg_chrdev_eptdev_destroy);
> if (ret)
> dev_warn(&rpdev->dev, "failed to nuke endpoints: %d\n", ret);
>
> diff --git a/drivers/rpmsg/rpmsg_char.h b/drivers/rpmsg/rpmsg_char.h
> new file mode 100644
> index 000000000000..0feb3ea9445c
> --- /dev/null
> +++ b/drivers/rpmsg/rpmsg_char.h
> @@ -0,0 +1,51 @@
> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> +/*
> + * Copyright (C) STMicroelectronics 2021.
> + */
> +
> +#ifndef __RPMSG_CHRDEV_H__
> +#define __RPMSG_CHRDEV_H__
> +
> +#if IS_ENABLED(CONFIG_RPMSG_CHAR)
> +/**
> + * rpmsg_chrdev_create_eptdev() - register char device based on an endpoint
> + * @rpdev: prepared rpdev to be used for creating endpoints
> + * @parent: parent device
> + * @chinfo: assiated endpoint channel information.
> + *
> + * This function create a new rpmsg char endpoint device to instantiate a new
> + * endpoint based on chinfo information.
> + */
> +int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent,
> + struct rpmsg_channel_info chinfo);
> +
> +/**
> + * rpmsg_chrdev_eptdev_destroy() - destroy created char device
> + * @data: parent device
> + * @chinfo: assiated endpoint channel information.
> + *
> + * This function create a new rpmsg char endpoint device to instantiate a new
> + * endpoint based on chinfo information.
> + */
> +int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data);
> +
> +#else /*IS_ENABLED(CONFIG_RPMSG_CHAR) */
> +
> +static inline int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev,
> + struct device *parent,
> + struct rpmsg_channel_info chinfo)
> +{
> + return -EINVAL;
> +}
> +
> +static inline int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data)
> +{
> + /* This shouldn't be possible */
> + WARN_ON(1);
> +
> + return 0;
> +}
> +
> +#endif /*IS_ENABLED(CONFIG_RPMSG_CHAR) */
> +
> +#endif /*__RPMSG_CHRDEV_H__ */
> --
> 2.17.1
>