platform: goldfish: pipe: Move the file-scope goldfish_pipe_miscdev variable into the driver state

This is a series of patches to move mutable file-scope variables
into the driver state. This change will help to introduce another
version of the pipe driver (with different state) for the older
host interface or having several instances of this device.
Signed-off-by: Roman Kiryanov <rkir@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/platform/goldfish/goldfish_pipe.c

@@ -211,6 +211,8 @@ struct goldfish_pipe_dev {
 
 	/* an irq tasklet to run goldfish_interrupt_task */
 	struct tasklet_struct irq_tasklet;
+
+	struct miscdevice miscdev;
 };
 
 static struct goldfish_pipe_dev goldfish_pipe_dev;
@@ -785,11 +787,14 @@ static const struct file_operations goldfish_pipe_fops = {
 	.release = goldfish_pipe_release,
 };
 
-static struct miscdevice goldfish_pipe_miscdev = {
-	.minor = MISC_DYNAMIC_MINOR,
-	.name = "goldfish_pipe",
-	.fops = &goldfish_pipe_fops,
-};
+static void init_miscdevice(struct miscdevice *miscdev)
+{
+	memset(miscdev, 0, sizeof(*miscdev));
+
+	miscdev->minor = MISC_DYNAMIC_MINOR;
+	miscdev->name = "goldfish_pipe";
+	miscdev->fops = &goldfish_pipe_fops;
+}
 
 static void write_pa_addr(void *addr, void __iomem *portl, void __iomem *porth)
 {
@@ -815,7 +820,8 @@ static int goldfish_pipe_device_init(struct platform_device *pdev)
 		return err;
 	}
 
-	err = misc_register(&goldfish_pipe_miscdev);
+	init_miscdevice(&dev->miscdev);
+	err = misc_register(&dev->miscdev);
 	if (err) {
 		dev_err(&pdev->dev, "unable to register v2 device\n");
 		return err;
@@ -860,7 +866,7 @@ static int goldfish_pipe_device_init(struct platform_device *pdev)
 
 static void goldfish_pipe_device_deinit(struct platform_device *pdev)
 {
-	misc_deregister(&goldfish_pipe_miscdev);
+	misc_deregister(&goldfish_pipe_dev.miscdev);
 	tasklet_kill(&goldfish_pipe_dev.irq_tasklet);
 	kfree(goldfish_pipe_dev.pipes);
 	free_page((unsigned long)goldfish_pipe_dev.buffers);