linux-stable/drivers/rpmsg/rpmsg_char.c
Arnaud Pouliquen 964e8bedd5 rpmsg: char: Return an error if device already open
The rpmsg_create_ept function is invoked when the device is opened.
As only one endpoint must be created per device. It is not possible to
open the same device twice. But there is nothing to prevent multi open.
Return -EBUSY when device is already opened to have a generic error
instead of relying on the back-end to potentially detect the error.

Without this patch for instance the GLINK driver return -EBUSY while
the virtio bus return -ENOSPC.

Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
Link: https://lore.kernel.org/r/20210311140413.31725-7-arnaud.pouliquen@foss.st.com
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
2021-03-17 14:16:58 -05:00

586 lines
14 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2016, Linaro Ltd.
* Copyright (c) 2012, Michal Simek <monstr@monstr.eu>
* Copyright (c) 2012, PetaLogix
* Copyright (c) 2011, Texas Instruments, Inc.
* Copyright (c) 2011, Google, Inc.
*
* Based on rpmsg performance statistics driver by Michal Simek, which in turn
* was based on TI & Google OMX rpmsg driver.
*/
#include <linux/cdev.h>
#include <linux/device.h>
#include <linux/fs.h>
#include <linux/idr.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/poll.h>
#include <linux/rpmsg.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <uapi/linux/rpmsg.h>
#include "rpmsg_internal.h"
#define RPMSG_DEV_MAX (MINORMASK + 1)
static dev_t rpmsg_major;
static struct class *rpmsg_class;
static DEFINE_IDA(rpmsg_ctrl_ida);
static DEFINE_IDA(rpmsg_ept_ida);
static DEFINE_IDA(rpmsg_minor_ida);
#define dev_to_eptdev(dev) container_of(dev, struct rpmsg_eptdev, dev)
#define cdev_to_eptdev(i_cdev) container_of(i_cdev, struct rpmsg_eptdev, cdev)
#define dev_to_ctrldev(dev) container_of(dev, struct rpmsg_ctrldev, dev)
#define cdev_to_ctrldev(i_cdev) container_of(i_cdev, struct rpmsg_ctrldev, cdev)
/**
* struct rpmsg_ctrldev - control device for instantiating endpoint devices
* @rpdev: underlaying rpmsg device
* @cdev: cdev for the ctrl device
* @dev: device for the ctrl device
*/
struct rpmsg_ctrldev {
struct rpmsg_device *rpdev;
struct cdev cdev;
struct device dev;
};
/**
* struct rpmsg_eptdev - endpoint device context
* @dev: endpoint device
* @cdev: cdev for the endpoint device
* @rpdev: underlaying rpmsg device
* @chinfo: info used to open the endpoint
* @ept_lock: synchronization of @ept modifications
* @ept: rpmsg endpoint reference, when open
* @queue_lock: synchronization of @queue operations
* @queue: incoming message queue
* @readq: wait object for incoming queue
*/
struct rpmsg_eptdev {
struct device dev;
struct cdev cdev;
struct rpmsg_device *rpdev;
struct rpmsg_channel_info chinfo;
struct mutex ept_lock;
struct rpmsg_endpoint *ept;
spinlock_t queue_lock;
struct sk_buff_head queue;
wait_queue_head_t readq;
};
static int rpmsg_eptdev_destroy(struct device *dev, void *data)
{
struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev);
mutex_lock(&eptdev->ept_lock);
if (eptdev->ept) {
rpmsg_destroy_ept(eptdev->ept);
eptdev->ept = NULL;
}
mutex_unlock(&eptdev->ept_lock);
/* wake up any blocked readers */
wake_up_interruptible(&eptdev->readq);
device_del(&eptdev->dev);
put_device(&eptdev->dev);
return 0;
}
static int rpmsg_ept_cb(struct rpmsg_device *rpdev, void *buf, int len,
void *priv, u32 addr)
{
struct rpmsg_eptdev *eptdev = priv;
struct sk_buff *skb;
skb = alloc_skb(len, GFP_ATOMIC);
if (!skb)
return -ENOMEM;
skb_put_data(skb, buf, len);
spin_lock(&eptdev->queue_lock);
skb_queue_tail(&eptdev->queue, skb);
spin_unlock(&eptdev->queue_lock);
/* wake up any blocking processes, waiting for new data */
wake_up_interruptible(&eptdev->readq);
return 0;
}
static int rpmsg_eptdev_open(struct inode *inode, struct file *filp)
{
struct rpmsg_eptdev *eptdev = cdev_to_eptdev(inode->i_cdev);
struct rpmsg_endpoint *ept;
struct rpmsg_device *rpdev = eptdev->rpdev;
struct device *dev = &eptdev->dev;
if (eptdev->ept)
return -EBUSY;
get_device(dev);
ept = rpmsg_create_ept(rpdev, rpmsg_ept_cb, eptdev, eptdev->chinfo);
if (!ept) {
dev_err(dev, "failed to open %s\n", eptdev->chinfo.name);
put_device(dev);
return -EINVAL;
}
eptdev->ept = ept;
filp->private_data = eptdev;
return 0;
}
static int rpmsg_eptdev_release(struct inode *inode, struct file *filp)
{
struct rpmsg_eptdev *eptdev = cdev_to_eptdev(inode->i_cdev);
struct device *dev = &eptdev->dev;
/* Close the endpoint, if it's not already destroyed by the parent */
mutex_lock(&eptdev->ept_lock);
if (eptdev->ept) {
rpmsg_destroy_ept(eptdev->ept);
eptdev->ept = NULL;
}
mutex_unlock(&eptdev->ept_lock);
/* Discard all SKBs */
skb_queue_purge(&eptdev->queue);
put_device(dev);
return 0;
}
static ssize_t rpmsg_eptdev_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
struct file *filp = iocb->ki_filp;
struct rpmsg_eptdev *eptdev = filp->private_data;
unsigned long flags;
struct sk_buff *skb;
int use;
if (!eptdev->ept)
return -EPIPE;
spin_lock_irqsave(&eptdev->queue_lock, flags);
/* Wait for data in the queue */
if (skb_queue_empty(&eptdev->queue)) {
spin_unlock_irqrestore(&eptdev->queue_lock, flags);
if (filp->f_flags & O_NONBLOCK)
return -EAGAIN;
/* Wait until we get data or the endpoint goes away */
if (wait_event_interruptible(eptdev->readq,
!skb_queue_empty(&eptdev->queue) ||
!eptdev->ept))
return -ERESTARTSYS;
/* We lost the endpoint while waiting */
if (!eptdev->ept)
return -EPIPE;
spin_lock_irqsave(&eptdev->queue_lock, flags);
}
skb = skb_dequeue(&eptdev->queue);
spin_unlock_irqrestore(&eptdev->queue_lock, flags);
if (!skb)
return -EFAULT;
use = min_t(size_t, iov_iter_count(to), skb->len);
if (copy_to_iter(skb->data, use, to) != use)
use = -EFAULT;
kfree_skb(skb);
return use;
}
static ssize_t rpmsg_eptdev_write_iter(struct kiocb *iocb,
struct iov_iter *from)
{
struct file *filp = iocb->ki_filp;
struct rpmsg_eptdev *eptdev = filp->private_data;
size_t len = iov_iter_count(from);
void *kbuf;
int ret;
kbuf = kzalloc(len, GFP_KERNEL);
if (!kbuf)
return -ENOMEM;
if (!copy_from_iter_full(kbuf, len, from)) {
ret = -EFAULT;
goto free_kbuf;
}
if (mutex_lock_interruptible(&eptdev->ept_lock)) {
ret = -ERESTARTSYS;
goto free_kbuf;
}
if (!eptdev->ept) {
ret = -EPIPE;
goto unlock_eptdev;
}
if (filp->f_flags & O_NONBLOCK)
ret = rpmsg_trysendto(eptdev->ept, kbuf, len, eptdev->chinfo.dst);
else
ret = rpmsg_sendto(eptdev->ept, kbuf, len, eptdev->chinfo.dst);
unlock_eptdev:
mutex_unlock(&eptdev->ept_lock);
free_kbuf:
kfree(kbuf);
return ret < 0 ? ret : len;
}
static __poll_t rpmsg_eptdev_poll(struct file *filp, poll_table *wait)
{
struct rpmsg_eptdev *eptdev = filp->private_data;
__poll_t mask = 0;
if (!eptdev->ept)
return EPOLLERR;
poll_wait(filp, &eptdev->readq, wait);
if (!skb_queue_empty(&eptdev->queue))
mask |= EPOLLIN | EPOLLRDNORM;
mask |= rpmsg_poll(eptdev->ept, filp, wait);
return mask;
}
static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd,
unsigned long arg)
{
struct rpmsg_eptdev *eptdev = fp->private_data;
if (cmd != RPMSG_DESTROY_EPT_IOCTL)
return -EINVAL;
return rpmsg_eptdev_destroy(&eptdev->dev, NULL);
}
static const struct file_operations rpmsg_eptdev_fops = {
.owner = THIS_MODULE,
.open = rpmsg_eptdev_open,
.release = rpmsg_eptdev_release,
.read_iter = rpmsg_eptdev_read_iter,
.write_iter = rpmsg_eptdev_write_iter,
.poll = rpmsg_eptdev_poll,
.unlocked_ioctl = rpmsg_eptdev_ioctl,
.compat_ioctl = compat_ptr_ioctl,
};
static ssize_t name_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);
return sprintf(buf, "%s\n", eptdev->chinfo.name);
}
static DEVICE_ATTR_RO(name);
static ssize_t src_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);
return sprintf(buf, "%d\n", eptdev->chinfo.src);
}
static DEVICE_ATTR_RO(src);
static ssize_t dst_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct rpmsg_eptdev *eptdev = dev_get_drvdata(dev);
return sprintf(buf, "%d\n", eptdev->chinfo.dst);
}
static DEVICE_ATTR_RO(dst);
static struct attribute *rpmsg_eptdev_attrs[] = {
&dev_attr_name.attr,
&dev_attr_src.attr,
&dev_attr_dst.attr,
NULL
};
ATTRIBUTE_GROUPS(rpmsg_eptdev);
static void rpmsg_eptdev_release_device(struct device *dev)
{
struct rpmsg_eptdev *eptdev = dev_to_eptdev(dev);
ida_simple_remove(&rpmsg_ept_ida, dev->id);
ida_simple_remove(&rpmsg_minor_ida, MINOR(eptdev->dev.devt));
cdev_del(&eptdev->cdev);
kfree(eptdev);
}
static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev,
struct rpmsg_channel_info chinfo)
{
struct rpmsg_device *rpdev = ctrldev->rpdev;
struct rpmsg_eptdev *eptdev;
struct device *dev;
int ret;
eptdev = kzalloc(sizeof(*eptdev), GFP_KERNEL);
if (!eptdev)
return -ENOMEM;
dev = &eptdev->dev;
eptdev->rpdev = rpdev;
eptdev->chinfo = chinfo;
mutex_init(&eptdev->ept_lock);
spin_lock_init(&eptdev->queue_lock);
skb_queue_head_init(&eptdev->queue);
init_waitqueue_head(&eptdev->readq);
device_initialize(dev);
dev->class = rpmsg_class;
dev->parent = &ctrldev->dev;
dev->groups = rpmsg_eptdev_groups;
dev_set_drvdata(dev, eptdev);
cdev_init(&eptdev->cdev, &rpmsg_eptdev_fops);
eptdev->cdev.owner = THIS_MODULE;
ret = ida_simple_get(&rpmsg_minor_ida, 0, RPMSG_DEV_MAX, GFP_KERNEL);
if (ret < 0)
goto free_eptdev;
dev->devt = MKDEV(MAJOR(rpmsg_major), ret);
ret = ida_simple_get(&rpmsg_ept_ida, 0, 0, GFP_KERNEL);
if (ret < 0)
goto free_minor_ida;
dev->id = ret;
dev_set_name(dev, "rpmsg%d", ret);
ret = cdev_add(&eptdev->cdev, dev->devt, 1);
if (ret)
goto free_ept_ida;
/* We can now rely on the release function for cleanup */
dev->release = rpmsg_eptdev_release_device;
ret = device_add(dev);
if (ret) {
dev_err(dev, "device_add failed: %d\n", ret);
put_device(dev);
}
return ret;
free_ept_ida:
ida_simple_remove(&rpmsg_ept_ida, dev->id);
free_minor_ida:
ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
free_eptdev:
put_device(dev);
kfree(eptdev);
return ret;
}
static int rpmsg_ctrldev_open(struct inode *inode, struct file *filp)
{
struct rpmsg_ctrldev *ctrldev = cdev_to_ctrldev(inode->i_cdev);
get_device(&ctrldev->dev);
filp->private_data = ctrldev;
return 0;
}
static int rpmsg_ctrldev_release(struct inode *inode, struct file *filp)
{
struct rpmsg_ctrldev *ctrldev = cdev_to_ctrldev(inode->i_cdev);
put_device(&ctrldev->dev);
return 0;
}
static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd,
unsigned long arg)
{
struct rpmsg_ctrldev *ctrldev = fp->private_data;
void __user *argp = (void __user *)arg;
struct rpmsg_endpoint_info eptinfo;
struct rpmsg_channel_info chinfo;
if (cmd != RPMSG_CREATE_EPT_IOCTL)
return -EINVAL;
if (copy_from_user(&eptinfo, argp, sizeof(eptinfo)))
return -EFAULT;
memcpy(chinfo.name, eptinfo.name, RPMSG_NAME_SIZE);
chinfo.name[RPMSG_NAME_SIZE-1] = '\0';
chinfo.src = eptinfo.src;
chinfo.dst = eptinfo.dst;
return rpmsg_eptdev_create(ctrldev, chinfo);
};
static const struct file_operations rpmsg_ctrldev_fops = {
.owner = THIS_MODULE,
.open = rpmsg_ctrldev_open,
.release = rpmsg_ctrldev_release,
.unlocked_ioctl = rpmsg_ctrldev_ioctl,
.compat_ioctl = compat_ptr_ioctl,
};
static void rpmsg_ctrldev_release_device(struct device *dev)
{
struct rpmsg_ctrldev *ctrldev = dev_to_ctrldev(dev);
ida_simple_remove(&rpmsg_ctrl_ida, dev->id);
ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
cdev_del(&ctrldev->cdev);
kfree(ctrldev);
}
static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev)
{
struct rpmsg_ctrldev *ctrldev;
struct device *dev;
int ret;
ctrldev = kzalloc(sizeof(*ctrldev), GFP_KERNEL);
if (!ctrldev)
return -ENOMEM;
ctrldev->rpdev = rpdev;
dev = &ctrldev->dev;
device_initialize(dev);
dev->parent = &rpdev->dev;
dev->class = rpmsg_class;
cdev_init(&ctrldev->cdev, &rpmsg_ctrldev_fops);
ctrldev->cdev.owner = THIS_MODULE;
ret = ida_simple_get(&rpmsg_minor_ida, 0, RPMSG_DEV_MAX, GFP_KERNEL);
if (ret < 0)
goto free_ctrldev;
dev->devt = MKDEV(MAJOR(rpmsg_major), ret);
ret = ida_simple_get(&rpmsg_ctrl_ida, 0, 0, GFP_KERNEL);
if (ret < 0)
goto free_minor_ida;
dev->id = ret;
dev_set_name(&ctrldev->dev, "rpmsg_ctrl%d", ret);
ret = cdev_add(&ctrldev->cdev, dev->devt, 1);
if (ret)
goto free_ctrl_ida;
/* We can now rely on the release function for cleanup */
dev->release = rpmsg_ctrldev_release_device;
ret = device_add(dev);
if (ret) {
dev_err(&rpdev->dev, "device_add failed: %d\n", ret);
put_device(dev);
}
dev_set_drvdata(&rpdev->dev, ctrldev);
return ret;
free_ctrl_ida:
ida_simple_remove(&rpmsg_ctrl_ida, dev->id);
free_minor_ida:
ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
free_ctrldev:
put_device(dev);
kfree(ctrldev);
return ret;
}
static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev)
{
struct rpmsg_ctrldev *ctrldev = dev_get_drvdata(&rpdev->dev);
int ret;
/* Destroy all endpoints */
ret = device_for_each_child(&ctrldev->dev, NULL, rpmsg_eptdev_destroy);
if (ret)
dev_warn(&rpdev->dev, "failed to nuke endpoints: %d\n", ret);
device_del(&ctrldev->dev);
put_device(&ctrldev->dev);
}
static struct rpmsg_driver rpmsg_chrdev_driver = {
.probe = rpmsg_chrdev_probe,
.remove = rpmsg_chrdev_remove,
.drv = {
.name = "rpmsg_chrdev",
},
};
static int rpmsg_chrdev_init(void)
{
int ret;
ret = alloc_chrdev_region(&rpmsg_major, 0, RPMSG_DEV_MAX, "rpmsg");
if (ret < 0) {
pr_err("rpmsg: failed to allocate char dev region\n");
return ret;
}
rpmsg_class = class_create(THIS_MODULE, "rpmsg");
if (IS_ERR(rpmsg_class)) {
pr_err("failed to create rpmsg class\n");
unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
return PTR_ERR(rpmsg_class);
}
ret = register_rpmsg_driver(&rpmsg_chrdev_driver);
if (ret < 0) {
pr_err("rpmsgchr: failed to register rpmsg driver\n");
class_destroy(rpmsg_class);
unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
}
return ret;
}
postcore_initcall(rpmsg_chrdev_init);
static void rpmsg_chrdev_exit(void)
{
unregister_rpmsg_driver(&rpmsg_chrdev_driver);
class_destroy(rpmsg_class);
unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
}
module_exit(rpmsg_chrdev_exit);
MODULE_ALIAS("rpmsg:rpmsg_chrdev");
MODULE_LICENSE("GPL v2");