USB: misc: legousbtower: semaphore to mutex

The dev->sem conforms to mutex style usage. This patch converts it to use
the struct mutex type, and new API.

There is also a small style fix around this comment,

/* unlock here as tower_delete frees dev */

Where I broke the line up to meet the 80 char limit.
Signed-off-by: Daniel Walker <dwalker@mvista.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/misc/legousbtower.c

@@ -205,7 +205,7 @@ static DEFINE_MUTEX(open_disc_mutex);
 
 /* Structure to hold all of our device specific stuff */
 struct lego_usb_tower {
-	struct semaphore	sem;		/* locks this structure */
+	struct mutex		lock;		/* locks this structure */
 	struct usb_device*	udev;		/* save off the usb device pointer */
 	unsigned char		minor;		/* the starting minor number for this device */
 
@@ -361,7 +361,7 @@ static int tower_open (struct inode *inode, struct file *file)
 	}
 
 	/* lock this device */
-	if (down_interruptible (&dev->sem)) {
+	if (mutex_lock_interruptible(&dev->lock)) {
 		mutex_unlock(&open_disc_mutex);
 	        retval = -ERESTARTSYS;
 		goto exit;
@@ -421,7 +421,7 @@ static int tower_open (struct inode *inode, struct file *file)
 	file->private_data = dev;
 
 unlock_exit:
-	up (&dev->sem);
+	mutex_unlock(&dev->lock);
 
 exit:
 	dbg(2, "%s: leave, return value %d ", __FUNCTION__, retval);
@@ -448,7 +448,7 @@ static int tower_release (struct inode *inode, struct file *file)
 	}
 
 	mutex_lock(&open_disc_mutex);
-	if (down_interruptible (&dev->sem)) {
+	if (mutex_lock_interruptible(&dev->lock)) {
 	        retval = -ERESTARTSYS;
 		goto exit;
 	}
@@ -460,7 +460,9 @@ static int tower_release (struct inode *inode, struct file *file)
 	}
 	if (dev->udev == NULL) {
 		/* the device was unplugged before the file was released */
-		up (&dev->sem);	/* unlock here as tower_delete frees dev */
+
+		/* unlock here as tower_delete frees dev */
+		mutex_unlock(&dev->lock);
 		tower_delete (dev);
 		goto exit;
 	}
@@ -473,7 +475,7 @@ static int tower_release (struct inode *inode, struct file *file)
 	dev->open_count = 0;
 
 unlock_exit:
-	up (&dev->sem);
+	mutex_unlock(&dev->lock);
 
 exit:
 	mutex_unlock(&open_disc_mutex);
@@ -586,7 +588,7 @@ static ssize_t tower_read (struct file *file, char __user *buffer, size_t count,
 	dev = (struct lego_usb_tower *)file->private_data;
 
 	/* lock this object */
-	if (down_interruptible (&dev->sem)) {
+	if (mutex_lock_interruptible(&dev->lock)) {
 		retval = -ERESTARTSYS;
 		goto exit;
 	}
@@ -653,7 +655,7 @@ static ssize_t tower_read (struct file *file, char __user *buffer, size_t count,
 
 unlock_exit:
 	/* unlock the device */
-	up (&dev->sem);
+	mutex_unlock(&dev->lock);
 
 exit:
 	dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
@@ -675,7 +677,7 @@ static ssize_t tower_write (struct file *file, const char __user *buffer, size_t
 	dev = (struct lego_usb_tower *)file->private_data;
 
 	/* lock this object */
-	if (down_interruptible (&dev->sem)) {
+	if (mutex_lock_interruptible(&dev->lock)) {
 		retval = -ERESTARTSYS;
 		goto exit;
 	}
@@ -737,7 +739,7 @@ static ssize_t tower_write (struct file *file, const char __user *buffer, size_t
 
 unlock_exit:
 	/* unlock the device */
-	up (&dev->sem);
+	mutex_unlock(&dev->lock);
 
 exit:
 	dbg(2, "%s: leave, return value %d", __FUNCTION__, retval);
@@ -862,7 +864,7 @@ static int tower_probe (struct usb_interface *interface, const struct usb_device
 		goto exit;
 	}
 
-	init_MUTEX (&dev->sem);
+	mutex_init(&dev->lock);
 
 	dev->udev = udev;
 	dev->open_count = 0;
@@ -1007,16 +1009,16 @@ static void tower_disconnect (struct usb_interface *interface)
 	/* give back our minor */
 	usb_deregister_dev (interface, &tower_class);
 
-	down (&dev->sem);
+	mutex_lock(&dev->lock);
 	mutex_unlock(&open_disc_mutex);
 
 	/* if the device is not opened, then we clean up right now */
 	if (!dev->open_count) {
-		up (&dev->sem);
+		mutex_unlock(&dev->lock);
 		tower_delete (dev);
 	} else {
 		dev->udev = NULL;
-		up (&dev->sem);
+		mutex_unlock(&dev->lock);
 	}
 
 	info("LEGO USB Tower #%d now disconnected", (minor - LEGO_USB_TOWER_MINOR_BASE));