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>

1 files changed, 16 insertions, 14 deletions

diff --git a/drivers/usb/misc/legousbtower.c b/drivers/usb/misc/legousbtower.c
index aab320085ebf..6664043f4645 100644
--- a/drivers/usb/misc/legousbtower.c
+++ b/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));