[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>

diff --git a/drivers/media/IR/lirc_dev.c b/drivers/media/IR/lirc_dev.c
index 8fdb7e11a138f11a712941a1f059c3c8782ac979..3ef15625fa8423972bf488a6e63e2abf15bf623f 100644 (file)
--- a/drivers/media/IR/lirc_dev.c
+++ b/drivers/media/IR/lirc_dev.c
@@ -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);
        }