mirror of
https://github.com/torvalds/linux.git
synced 2024-11-25 05:32:00 +00:00
cb787f4ac0
no_llseek had been defined to NULL two years ago, in commit 868941b144
("fs: remove no_llseek")
To quote that commit,
At -rc1 we'll need do a mechanical removal of no_llseek -
git grep -l -w no_llseek | grep -v porting.rst | while read i; do
sed -i '/\<no_llseek\>/d' $i
done
would do it.
Unfortunately, that hadn't been done. Linus, could you do that now, so
that we could finally put that thing to rest? All instances are of the
form
.llseek = no_llseek,
so it's obviously safe.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
326 lines
8.2 KiB
C
326 lines
8.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* Media device node
|
|
*
|
|
* Copyright (C) 2010 Nokia Corporation
|
|
*
|
|
* Based on drivers/media/video/v4l2_dev.c code authored by
|
|
* Mauro Carvalho Chehab <mchehab@kernel.org> (version 2)
|
|
* Alan Cox, <alan@lxorguk.ukuu.org.uk> (version 1)
|
|
*
|
|
* Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
|
|
* Sakari Ailus <sakari.ailus@iki.fi>
|
|
*
|
|
* --
|
|
*
|
|
* Generic media device node infrastructure to register and unregister
|
|
* character devices using a dynamic major number and proper reference
|
|
* counting.
|
|
*/
|
|
|
|
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
|
|
|
|
#include <linux/errno.h>
|
|
#include <linux/init.h>
|
|
#include <linux/module.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/kmod.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/string.h>
|
|
#include <linux/types.h>
|
|
#include <linux/uaccess.h>
|
|
|
|
#include <media/media-devnode.h>
|
|
#include <media/media-device.h>
|
|
|
|
#define MEDIA_NUM_DEVICES 256
|
|
#define MEDIA_NAME "media"
|
|
|
|
static dev_t media_dev_t;
|
|
|
|
/*
|
|
* Active devices
|
|
*/
|
|
static DEFINE_MUTEX(media_devnode_lock);
|
|
static DECLARE_BITMAP(media_devnode_nums, MEDIA_NUM_DEVICES);
|
|
|
|
/* Called when the last user of the media device exits. */
|
|
static void media_devnode_release(struct device *cd)
|
|
{
|
|
struct media_devnode *devnode = to_media_devnode(cd);
|
|
|
|
mutex_lock(&media_devnode_lock);
|
|
/* Mark device node number as free */
|
|
clear_bit(devnode->minor, media_devnode_nums);
|
|
mutex_unlock(&media_devnode_lock);
|
|
|
|
/* Release media_devnode and perform other cleanups as needed. */
|
|
if (devnode->release)
|
|
devnode->release(devnode);
|
|
|
|
kfree(devnode);
|
|
pr_debug("%s: Media Devnode Deallocated\n", __func__);
|
|
}
|
|
|
|
static const struct bus_type media_bus_type = {
|
|
.name = MEDIA_NAME,
|
|
};
|
|
|
|
static ssize_t media_read(struct file *filp, char __user *buf,
|
|
size_t sz, loff_t *off)
|
|
{
|
|
struct media_devnode *devnode = media_devnode_data(filp);
|
|
|
|
if (!devnode->fops->read)
|
|
return -EINVAL;
|
|
if (!media_devnode_is_registered(devnode))
|
|
return -EIO;
|
|
return devnode->fops->read(filp, buf, sz, off);
|
|
}
|
|
|
|
static ssize_t media_write(struct file *filp, const char __user *buf,
|
|
size_t sz, loff_t *off)
|
|
{
|
|
struct media_devnode *devnode = media_devnode_data(filp);
|
|
|
|
if (!devnode->fops->write)
|
|
return -EINVAL;
|
|
if (!media_devnode_is_registered(devnode))
|
|
return -EIO;
|
|
return devnode->fops->write(filp, buf, sz, off);
|
|
}
|
|
|
|
static __poll_t media_poll(struct file *filp,
|
|
struct poll_table_struct *poll)
|
|
{
|
|
struct media_devnode *devnode = media_devnode_data(filp);
|
|
|
|
if (!media_devnode_is_registered(devnode))
|
|
return EPOLLERR | EPOLLHUP;
|
|
if (!devnode->fops->poll)
|
|
return DEFAULT_POLLMASK;
|
|
return devnode->fops->poll(filp, poll);
|
|
}
|
|
|
|
static long
|
|
__media_ioctl(struct file *filp, unsigned int cmd, unsigned long arg,
|
|
long (*ioctl_func)(struct file *filp, unsigned int cmd,
|
|
unsigned long arg))
|
|
{
|
|
struct media_devnode *devnode = media_devnode_data(filp);
|
|
|
|
if (!ioctl_func)
|
|
return -ENOTTY;
|
|
|
|
if (!media_devnode_is_registered(devnode))
|
|
return -EIO;
|
|
|
|
return ioctl_func(filp, cmd, arg);
|
|
}
|
|
|
|
static long media_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
|
|
{
|
|
struct media_devnode *devnode = media_devnode_data(filp);
|
|
|
|
return __media_ioctl(filp, cmd, arg, devnode->fops->ioctl);
|
|
}
|
|
|
|
#ifdef CONFIG_COMPAT
|
|
|
|
static long media_compat_ioctl(struct file *filp, unsigned int cmd,
|
|
unsigned long arg)
|
|
{
|
|
struct media_devnode *devnode = media_devnode_data(filp);
|
|
|
|
return __media_ioctl(filp, cmd, arg, devnode->fops->compat_ioctl);
|
|
}
|
|
|
|
#endif /* CONFIG_COMPAT */
|
|
|
|
/* Override for the open function */
|
|
static int media_open(struct inode *inode, struct file *filp)
|
|
{
|
|
struct media_devnode *devnode;
|
|
int ret;
|
|
|
|
/* Check if the media device is available. This needs to be done with
|
|
* the media_devnode_lock held to prevent an open/unregister race:
|
|
* without the lock, the device could be unregistered and freed between
|
|
* the media_devnode_is_registered() and get_device() calls, leading to
|
|
* a crash.
|
|
*/
|
|
mutex_lock(&media_devnode_lock);
|
|
devnode = container_of(inode->i_cdev, struct media_devnode, cdev);
|
|
/* return ENXIO if the media device has been removed
|
|
already or if it is not registered anymore. */
|
|
if (!media_devnode_is_registered(devnode)) {
|
|
mutex_unlock(&media_devnode_lock);
|
|
return -ENXIO;
|
|
}
|
|
/* and increase the device refcount */
|
|
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;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* Override for the release function */
|
|
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);
|
|
|
|
filp->private_data = NULL;
|
|
|
|
/* decrease the refcount unconditionally since the release()
|
|
return value is ignored. */
|
|
put_device(&devnode->dev);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct file_operations media_devnode_fops = {
|
|
.owner = THIS_MODULE,
|
|
.read = media_read,
|
|
.write = media_write,
|
|
.open = media_open,
|
|
.unlocked_ioctl = media_ioctl,
|
|
#ifdef CONFIG_COMPAT
|
|
.compat_ioctl = media_compat_ioctl,
|
|
#endif /* CONFIG_COMPAT */
|
|
.release = media_release,
|
|
.poll = media_poll,
|
|
};
|
|
|
|
int __must_check media_devnode_register(struct media_device *mdev,
|
|
struct media_devnode *devnode,
|
|
struct module *owner)
|
|
{
|
|
int minor;
|
|
int ret;
|
|
|
|
/* Part 1: Find a free minor number */
|
|
mutex_lock(&media_devnode_lock);
|
|
minor = find_first_zero_bit(media_devnode_nums, MEDIA_NUM_DEVICES);
|
|
if (minor == MEDIA_NUM_DEVICES) {
|
|
mutex_unlock(&media_devnode_lock);
|
|
pr_err("could not get a free minor\n");
|
|
kfree(devnode);
|
|
return -ENFILE;
|
|
}
|
|
|
|
set_bit(minor, media_devnode_nums);
|
|
mutex_unlock(&media_devnode_lock);
|
|
|
|
devnode->minor = minor;
|
|
devnode->media_dev = mdev;
|
|
|
|
/* Part 1: Initialize dev now to use dev.kobj for cdev.kobj.parent */
|
|
devnode->dev.bus = &media_bus_type;
|
|
devnode->dev.devt = MKDEV(MAJOR(media_dev_t), devnode->minor);
|
|
devnode->dev.release = media_devnode_release;
|
|
if (devnode->parent)
|
|
devnode->dev.parent = devnode->parent;
|
|
dev_set_name(&devnode->dev, "media%d", devnode->minor);
|
|
device_initialize(&devnode->dev);
|
|
|
|
/* Part 2: Initialize the character device */
|
|
cdev_init(&devnode->cdev, &media_devnode_fops);
|
|
devnode->cdev.owner = owner;
|
|
kobject_set_name(&devnode->cdev.kobj, "media%d", devnode->minor);
|
|
|
|
/* Part 3: Add the media and char device */
|
|
set_bit(MEDIA_FLAG_REGISTERED, &devnode->flags);
|
|
ret = cdev_device_add(&devnode->cdev, &devnode->dev);
|
|
if (ret < 0) {
|
|
clear_bit(MEDIA_FLAG_REGISTERED, &devnode->flags);
|
|
pr_err("%s: cdev_device_add failed\n", __func__);
|
|
goto cdev_add_error;
|
|
}
|
|
|
|
return 0;
|
|
|
|
cdev_add_error:
|
|
mutex_lock(&media_devnode_lock);
|
|
clear_bit(devnode->minor, media_devnode_nums);
|
|
devnode->media_dev = NULL;
|
|
mutex_unlock(&media_devnode_lock);
|
|
|
|
put_device(&devnode->dev);
|
|
return ret;
|
|
}
|
|
|
|
void media_devnode_unregister_prepare(struct media_devnode *devnode)
|
|
{
|
|
/* Check if devnode was ever registered at all */
|
|
if (!media_devnode_is_registered(devnode))
|
|
return;
|
|
|
|
mutex_lock(&media_devnode_lock);
|
|
clear_bit(MEDIA_FLAG_REGISTERED, &devnode->flags);
|
|
mutex_unlock(&media_devnode_lock);
|
|
}
|
|
|
|
void media_devnode_unregister(struct media_devnode *devnode)
|
|
{
|
|
mutex_lock(&media_devnode_lock);
|
|
/* Delete the cdev on this minor as well */
|
|
cdev_device_del(&devnode->cdev, &devnode->dev);
|
|
devnode->media_dev = NULL;
|
|
mutex_unlock(&media_devnode_lock);
|
|
|
|
put_device(&devnode->dev);
|
|
}
|
|
|
|
/*
|
|
* Initialise media for linux
|
|
*/
|
|
static int __init media_devnode_init(void)
|
|
{
|
|
int ret;
|
|
|
|
pr_info("Linux media interface: v0.10\n");
|
|
ret = alloc_chrdev_region(&media_dev_t, 0, MEDIA_NUM_DEVICES,
|
|
MEDIA_NAME);
|
|
if (ret < 0) {
|
|
pr_warn("unable to allocate major\n");
|
|
return ret;
|
|
}
|
|
|
|
ret = bus_register(&media_bus_type);
|
|
if (ret < 0) {
|
|
unregister_chrdev_region(media_dev_t, MEDIA_NUM_DEVICES);
|
|
pr_warn("bus_register failed\n");
|
|
return -EIO;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void __exit media_devnode_exit(void)
|
|
{
|
|
bus_unregister(&media_bus_type);
|
|
unregister_chrdev_region(media_dev_t, MEDIA_NUM_DEVICES);
|
|
}
|
|
|
|
subsys_initcall(media_devnode_init);
|
|
module_exit(media_devnode_exit)
|
|
|
|
MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
|
|
MODULE_DESCRIPTION("Device node registration for media drivers");
|
|
MODULE_LICENSE("GPL");
|