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Date: Mon, 1 Nov 2021 11:55:12 -0500
From: Bjorn Andersson <bjorn.andersson@...aro.org>
To: Arnaud Pouliquen <arnaud.pouliquen@...s.st.com>
Cc: Ohad Ben-Cohen <ohad@...ery.com>,
Mathieu Poirier <mathieu.poirier@...aro.org>,
linux-remoteproc@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-stm32@...md-mailman.stormreply.com, julien.massot@....bzh
Subject: Re: [PATCH v6 01/10] rpmsg: char: Export eptdev create an destroy
functions
On Fri 22 Oct 07:54 CDT 2021, Arnaud Pouliquen wrote:
> To prepare the split of the code related to the control (ctrldev)
> and the endpoint (eptdev) devices in 2 separate files:
>
> - Rename and export the functions in rpmsg_char.h.
>
> - Suppress the dependency with the rpmsg_ctrldev struct in the
> rpmsg_eptdev_create function.
>
> Suggested-by: Mathieu Poirier <mathieu.poirier@...aro.org>
> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@...s.st.com>
> ---
> update vs previous revision:
> - add comment to explain the IS_REACHABLE usage
> - remove Mathieu Poirier reviewed-by as patch updated
> ---
> drivers/rpmsg/rpmsg_char.c | 18 +++++++-----
> drivers/rpmsg/rpmsg_char.h | 57 ++++++++++++++++++++++++++++++++++++++
> 2 files changed, 68 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 b5907b80727c..941c5c54dd72 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@...str.eu>
> * Copyright (c) 2012, PetaLogix
> @@ -22,6 +23,8 @@
> #include <linux/uaccess.h>
> #include <uapi/linux/rpmsg.h>
>
> +#include "rpmsg_char.h"
> +
> #define RPMSG_DEV_MAX (MINORMASK + 1)
>
> static dev_t rpmsg_major;
> @@ -76,7 +79,7 @@ struct rpmsg_eptdev {
> wait_queue_head_t readq;
> };
>
> -static int rpmsg_eptdev_destroy(struct device *dev, void *data)
> +int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data)
> {
> struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev);
>
> @@ -95,6 +98,7 @@ static int rpmsg_eptdev_destroy(struct device *dev, void *data)
>
> return 0;
> }
> +EXPORT_SYMBOL(rpmsg_chrdev_eptdev_destroy);
>
> static int rpmsg_ept_cb(struct rpmsg_device *rpdev, void *buf, int len,
> void *priv, u32 addr)
> @@ -278,7 +282,7 @@ 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_chrdev_eptdev_destroy(&eptdev->dev, NULL);
> }
>
> static const struct file_operations rpmsg_eptdev_fops = {
> @@ -337,10 +341,9 @@ static void rpmsg_eptdev_release_device(struct device *dev)
> kfree(eptdev);
> }
>
> -static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev,
> +int rpmsg_chrdev_eptdev_create(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;
> @@ -360,7 +363,7 @@ 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);
>
> @@ -403,6 +406,7 @@ static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev,
>
> return ret;
> }
> +EXPORT_SYMBOL(rpmsg_chrdev_eptdev_create);
>
> static int rpmsg_ctrldev_open(struct inode *inode, struct file *filp)
> {
> @@ -442,7 +446,7 @@ 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_eptdev_create(ctrldev->rpdev, &ctrldev->dev, chinfo);
> };
>
> static const struct file_operations rpmsg_ctrldev_fops = {
> @@ -528,7 +532,7 @@ 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..109c2c43005f
> --- /dev/null
> +++ b/drivers/rpmsg/rpmsg_char.h
> @@ -0,0 +1,57 @@
> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> +/*
> + * Copyright (C) STMicroelectronics 2021.
> + */
> +
> +#ifndef __RPMSG_CHRDEV_H__
> +#define __RPMSG_CHRDEV_H__
> +
> +/*
> + * The IS_REACHABLE macro is used here to prevent unresolved symbol error during link,
> + * building with RPMSG_CHAR=m and RPMSG_CTRL=y configuration.
> + * In such case a kernel warning is printed to help develloper to fix the issue.
> + */
I think we concluded that RPMSG_CHAR=n, RPMSG_CTRL=y is a valid
combination. If so I presume you don't want the user to get the kernel
log spammed by the WARN_ON()?
Afaict this should only ever be invoked by rpmsg_ctrl and with
RPMSG_CHAR disabled the related ioctls should just fail nicely.
As such. I think this should be #if IS_ENABLED() and we should put:
depends on RPMSG_CHAR || RPMSG_CHAR=n
in the RPMSG_CTRL Kconfig.
Regards,
Bjorn
> +
> +#if IS_REACHABLE(CONFIG_RPMSG_CHAR)
> +/**
> + * rpmsg_chrdev_eptdev_create() - register char device based on an endpoint
> + * @rpdev: prepared rpdev to be used for creating endpoints
> + * @parent: parent device
> + * @chinfo: associated 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_create(struct rpmsg_device *rpdev, struct device *parent,
> + struct rpmsg_channel_info chinfo);
> +
> +/**
> + * rpmsg_chrdev_eptdev_destroy() - destroy created char device endpoint.
> + * @data: private data associated to the endpoint device
> + *
> + * This function destroys a rpmsg char endpoint device created by the RPMSG_DESTROY_EPT_IOCTL
> + * control.
> + */
> +int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data);
> +
> +#else /*IS_REACHABLE(CONFIG_RPMSG_CHAR) */
> +
> +static inline int rpmsg_chrdev_eptdev_create(struct rpmsg_device *rpdev, struct device *parent,
> + struct rpmsg_channel_info chinfo)
> +{
> + /* This shouldn't be possible */
> + WARN_ON(1);
> + 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_REACHABLE(CONFIG_RPMSG_CHAR) */
> +
> +#endif /*__RPMSG_CHRDEV_H__ */
> --
> 2.17.1
>
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