[media] lirc_dev: store cdev in irctl, up maxdevs

Store the cdev pointer in struct irctl, allocated dynamically as needed,
rather than having a static array. At the same time, recycle some of the
saved memory to nudge the maximum number of lirc devices supported up a
ways -- its not that uncommon these days, now that we have the rc-core
lirc bridge driver, to see a system with at least 4 raw IR receivers.
(consider a mythtv backend with several video capture devices and the
possible need for IR transmit hardware).

Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/rc/lirc_dev.c

@@ -55,14 +55,15 @@ struct irctl {
 	struct lirc_buffer *buf;
 	unsigned int chunk_size;
 
+	struct cdev *cdev;
+
 	struct task_struct *task;
 	long jiffies_to_wait;
 };
 
 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;
@@ -167,9 +168,13 @@ static struct file_operations lirc_dev_fops = {
 
 static int lirc_cdev_add(struct irctl *ir)
 {
-	int retval;
+	int retval = -ENOMEM;
 	struct lirc_driver *d = &ir->d;
-	struct cdev *cdev = &cdevs[d->minor];
+	struct cdev *cdev;
+
+	cdev = kzalloc(sizeof(*cdev), GFP_KERNEL);
+	if (!cdev)
+		goto err_out;
 
 	if (d->fops) {
 		cdev_init(cdev, d->fops);
@@ -180,12 +185,20 @@ static int lirc_cdev_add(struct irctl *ir)
 	}
 	retval = kobject_set_name(&cdev->kobj, "lirc%d", d->minor);
 	if (retval)
-		return retval;
+		goto err_out;
 
 	retval = cdev_add(cdev, MKDEV(MAJOR(lirc_base_dev), d->minor), 1);
-	if (retval)
+	if (retval) {
 		kobject_put(&cdev->kobj);
+		goto err_out;
+	}
+
+	ir->cdev = cdev;
+
+	return 0;
 
+err_out:
+	kfree(cdev);
 	return retval;
 }
 
@@ -214,7 +227,7 @@ int lirc_register_driver(struct lirc_driver *d)
 	if (MAX_IRCTL_DEVICES <= d->minor) {
 		dev_err(d->dev, "lirc_dev: lirc_register_driver: "
 			"\"minor\" must be between 0 and %d (%d)!\n",
-			MAX_IRCTL_DEVICES-1, d->minor);
+			MAX_IRCTL_DEVICES - 1, d->minor);
 		err = -EBADRQC;
 		goto out;
 	}
@@ -369,7 +382,7 @@ int lirc_unregister_driver(int minor)
 
 	if (minor < 0 || minor >= MAX_IRCTL_DEVICES) {
 		printk(KERN_ERR "lirc_dev: %s: minor (%d) must be between "
-		       "0 and %d!\n", __func__, minor, MAX_IRCTL_DEVICES-1);
+		       "0 and %d!\n", __func__, minor, MAX_IRCTL_DEVICES - 1);
 		return -EBADRQC;
 	}
 
@@ -380,7 +393,7 @@ int lirc_unregister_driver(int minor)
 		return -ENOENT;
 	}
 
-	cdev = &cdevs[minor];
+	cdev = ir->cdev;
 
 	mutex_lock(&lirc_dev_lock);
 
@@ -410,6 +423,7 @@ int lirc_unregister_driver(int minor)
 	} else {
 		lirc_irctl_cleanup(ir);
 		cdev_del(cdev);
+		kfree(cdev);
 		kfree(ir);
 		irctls[minor] = NULL;
 	}
@@ -453,7 +467,7 @@ int lirc_dev_fop_open(struct inode *inode, struct file *file)
 		goto error;
 	}
 
-	cdev = &cdevs[iminor(inode)];
+	cdev = ir->cdev;
 	if (try_module_get(cdev->owner)) {
 		ir->open++;
 		retval = ir->d.set_use_inc(ir->d.data);
@@ -484,13 +498,15 @@ 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)];
+	struct cdev *cdev;
 
 	if (!ir) {
 		printk(KERN_ERR "%s: called with invalid irctl\n", __func__);
 		return -EINVAL;
 	}
 
+	cdev = ir->cdev;
+
 	dev_dbg(ir->d.dev, LOGHEAD "close called\n", ir->d.name, ir->d.minor);
 
 	WARN_ON(mutex_lock_killable(&lirc_dev_lock));
@@ -503,6 +519,7 @@ int lirc_dev_fop_close(struct inode *inode, struct file *file)
 		lirc_irctl_cleanup(ir);
 		cdev_del(cdev);
 		irctls[ir->d.minor] = NULL;
+		kfree(cdev);
 		kfree(ir);
 	}
 

include/media/lirc_dev.h

@@ -9,7 +9,7 @@
 #ifndef _LINUX_LIRC_DEV_H
 #define _LINUX_LIRC_DEV_H
 
-#define MAX_IRCTL_DEVICES 4
+#define MAX_IRCTL_DEVICES 8
 #define BUFLEN            16
 
 #define mod(n, div) ((n) % (div))