USB: use mutex instead of semaphore in the FTDI ELAN driver

The FTDI ELAN driver uses a semaphore as mutex. Use the mutex API
instead of the (binary) semaphore.
Signed-off-by: Matthias Kaehlcke <matthias.kaehlcke@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/misc/ftdi-elan.c

@@ -44,6 +44,7 @@
 #include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/kref.h>
+#include <linux/mutex.h>
 #include <asm/uaccess.h>
 #include <linux/usb.h>
 #include <linux/workqueue.h>
@@ -64,7 +65,7 @@ static struct workqueue_struct *respond_queue;
 * ftdi_module_lock exists to protect access to global variables
 *
 */
-static struct semaphore ftdi_module_lock;
+static struct mutex ftdi_module_lock;
 static int ftdi_instances = 0;
 static struct list_head ftdi_static_list;
 /*
@@ -199,10 +200,10 @@ static void ftdi_elan_delete(struct kref *kref)
         dev_warn(&ftdi->udev->dev, "FREEING ftdi=%p\n", ftdi);
         usb_put_dev(ftdi->udev);
         ftdi->disconnected += 1;
-        down(&ftdi_module_lock);
+        mutex_lock(&ftdi_module_lock);
         list_del_init(&ftdi->ftdi_list);
         ftdi_instances -= 1;
-        up(&ftdi_module_lock);
+        mutex_unlock(&ftdi_module_lock);
         kfree(ftdi->bulk_in_buffer);
         ftdi->bulk_in_buffer = NULL;
 }
@@ -2780,10 +2781,10 @@ static int ftdi_elan_probe(struct usb_interface *interface,
                 return -ENOMEM;
         }
         memset(ftdi, 0x00, sizeof(struct usb_ftdi));
-        down(&ftdi_module_lock);
+        mutex_lock(&ftdi_module_lock);
         list_add_tail(&ftdi->ftdi_list, &ftdi_static_list);
         ftdi->sequence_num = ++ftdi_instances;
-        up(&ftdi_module_lock);
+        mutex_unlock(&ftdi_module_lock);
         ftdi_elan_init_kref(ftdi);
         init_MUTEX(&ftdi->sw_lock);
         ftdi->udev = usb_get_dev(interface_to_usbdev(interface));
@@ -2909,7 +2910,7 @@ static int __init ftdi_elan_init(void)
         int result;
         printk(KERN_INFO "driver %s built at %s on %s\n", ftdi_elan_driver.name,
 	       __TIME__, __DATE__);
-        init_MUTEX(&ftdi_module_lock);
+        mutex_init(&ftdi_module_lock);
         INIT_LIST_HEAD(&ftdi_static_list);
         status_queue = create_singlethread_workqueue("ftdi-status-control");
 	if (!status_queue)