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[media] lirc_dev: rework storage for cdev data 

Fixes an oops when an lirc driver that doesn't provide its own fops is
unplugged while the lirc cdev is open. Tested with lirc_igorplugusb,
with a special thanks to Timo Boettcher for providing the test hardware.

Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Jarod Wilson 2010-10-18 18:39:20 -03:00 committed by Mauro Carvalho Chehab
parent 09c8dd8de6
commit c1cbb7029e
1 changed files with 23 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

40
drivers/media/IR/lirc_dev.c
View File

@ -58,13 +58,12 @@ struct irctl {
struct task_struct *task;
long jiffies_to_wait;
struct cdev cdev;
};
static DEFINE_MUTEX(lirc_dev_lock);
static struct irctl *irctls[MAX_IRCTL_DEVICES];
static struct cdev cdevs[MAX_IRCTL_DEVICES];
/* Only used for sysfs but defined to void otherwise */
static struct class *lirc_class;
@ -170,19 +169,20 @@ static int lirc_cdev_add(struct irctl *ir)
{
int retval;
struct lirc_driver *d = &ir->d;
struct cdev *cdev = &cdevs[d->minor];
if (d->fops) {
cdev_init(&ir->cdev, d->fops);
ir->cdev.owner = d->owner;
cdev_init(cdev, d->fops);
cdev->owner = d->owner;
} else {
cdev_init(&ir->cdev, &lirc_dev_fops);
ir->cdev.owner = THIS_MODULE;
cdev_init(cdev, &lirc_dev_fops);
cdev->owner = THIS_MODULE;
}
kobject_set_name(&ir->cdev.kobj, "lirc%d", d->minor);
kobject_set_name(&cdev->kobj, "lirc%d", d->minor);
retval = cdev_add(&ir->cdev, MKDEV(MAJOR(lirc_base_dev), d->minor), 1);
retval = cdev_add(cdev, MKDEV(MAJOR(lirc_base_dev), d->minor), 1);
if (retval)
kobject_put(&ir->cdev.kobj);
kobject_put(&cdev->kobj);
return retval;
}
@ -363,6 +363,7 @@ EXPORT_SYMBOL(lirc_register_driver);
int lirc_unregister_driver(int minor)
{
struct irctl *ir;
struct cdev *cdev;
if (minor < 0 || minor >= MAX_IRCTL_DEVICES) {
printk(KERN_ERR "lirc_dev: %s: minor (%d) must be between "
@ -377,6 +378,8 @@ int lirc_unregister_driver(int minor)
return -ENOENT;
}
cdev = &cdevs[minor];
mutex_lock(&lirc_dev_lock);
if (ir->d.minor != minor) {
@ -400,11 +403,11 @@ int lirc_unregister_driver(int minor)
wake_up_interruptible(&ir->buf->wait_poll);
mutex_lock(&ir->irctl_lock);
ir->d.set_use_dec(ir->d.data);
module_put(ir->cdev.owner);
module_put(cdev->owner);
mutex_unlock(&ir->irctl_lock);
} else {
lirc_irctl_cleanup(ir);
cdev_del(&ir->cdev);
cdev_del(cdev);
kfree(ir);
irctls[minor] = NULL;
}
@ -418,6 +421,7 @@ EXPORT_SYMBOL(lirc_unregister_driver);
int lirc_dev_fop_open(struct inode *inode, struct file *file)
{
struct irctl *ir;
struct cdev *cdev;
int retval = 0;
if (iminor(inode) >= MAX_IRCTL_DEVICES) {
@ -447,13 +451,14 @@ int lirc_dev_fop_open(struct inode *inode, struct file *file)
goto error;
}
if (try_module_get(ir->cdev.owner)) {
++ir->open;
cdev = &cdevs[iminor(inode)];
if (try_module_get(cdev->owner)) {
ir->open++;
retval = ir->d.set_use_inc(ir->d.data);
if (retval) {
module_put(ir->cdev.owner);
--ir->open;
module_put(cdev->owner);
ir->open--;
} else {
lirc_buffer_clear(ir->buf);
}
@ -475,6 +480,7 @@ EXPORT_SYMBOL(lirc_dev_fop_open);
int lirc_dev_fop_close(struct inode *inode, struct file *file)
{
struct irctl *ir = irctls[iminor(inode)];
struct cdev *cdev = &cdevs[iminor(inode)];
if (!ir) {
printk(KERN_ERR "%s: called with invalid irctl\n", __func__);
@ -488,10 +494,10 @@ int lirc_dev_fop_close(struct inode *inode, struct file *file)
ir->open--;
if (ir->attached) {
ir->d.set_use_dec(ir->d.data);
module_put(ir->cdev.owner);
module_put(cdev->owner);
} else {
lirc_irctl_cleanup(ir);
cdev_del(&ir->cdev);
cdev_del(cdev);
irctls[ir->d.minor] = NULL;
kfree(ir);
}