USB: use mutex instead of semaphore in the Adutux driver

The Adutux 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>

1 files changed, 18 insertions, 17 deletions

diff --git a/drivers/usb/misc/adutux.c b/drivers/usb/misc/adutux.c
index d72c42e5f22d..274d08ecf291 100644
--- a/drivers/usb/misc/adutux.c
+++ b/drivers/usb/misc/adutux.c
@@ -24,6 +24,7 @@
 #include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/usb.h>
+#include <linux/mutex.h>
 #include <asm/uaccess.h>
 
 #ifdef CONFIG_USB_DEBUG
@@ -80,7 +81,7 @@ MODULE_DEVICE_TABLE(usb, device_table);
 
 /* Structure to hold all of our device specific stuff */
 struct adu_device {
-        struct semaphore        sem; /* locks this structure */
+        struct mutex            mtx; /* locks this structure */
         struct usb_device*      udev; /* save off the usb device pointer */
         struct usb_interface*   interface;
         unsigned char           minor; /* the starting minor number for this device */
@@ -269,8 +270,8 @@ static int adu_open(struct inode *inode, struct file *file)
         }
 
         /* lock this device */
-        if ((retval = down_interruptible(&dev->sem))) {
-                dbg(2, "%s : sem down failed", __FUNCTION__);
+        if ((retval = mutex_lock_interruptible(&dev->mtx))) {
+                dbg(2, "%s : mutex lock failed", __FUNCTION__);
                 goto exit_no_device;
         }
 
@@ -299,7 +300,7 @@ static int adu_open(struct inode *inode, struct file *file)
                 if (retval)
                         --dev->open_count;
         }
-        up(&dev->sem);
+        mutex_unlock(&dev->mtx);
 
 exit_no_device:
         dbg(2,"%s : leave, return value %d ", __FUNCTION__, retval);
@@ -347,7 +348,7 @@ static int adu_release(struct inode *inode, struct file *file)
         }
 
         /* lock our device */
-        down(&dev->sem); /* not interruptible */
+        mutex_lock(&dev->mtx); /* not interruptible */
 
         if (dev->open_count <= 0) {
                 dbg(1," %s : device not opened", __FUNCTION__);
@@ -357,7 +358,7 @@ static int adu_release(struct inode *inode, struct file *file)
 
         if (dev->udev == NULL) {
                 /* the device was unplugged before the file was released */
-                up(&dev->sem);
+                mutex_unlock(&dev->mtx);
                 adu_delete(dev);
                 dev = NULL;
         } else {
@@ -367,7 +368,7 @@ static int adu_release(struct inode *inode, struct file *file)
 
 exit:
         if (dev)
-                up(&dev->sem);
+                mutex_unlock(&dev->mtx);
         dbg(2," %s : leave, return value %d", __FUNCTION__, retval);
         return retval;
 }
@@ -390,7 +391,7 @@ static ssize_t adu_read(struct file *file, __user char *buffer, size_t count,
         dev = file->private_data;
         dbg(2," %s : dev=%p", __FUNCTION__, dev);
         /* lock this object */
-        if (down_interruptible(&dev->sem))
+        if (mutex_lock_interruptible(&dev->mtx))
                 return -ERESTARTSYS;
 
         /* verify that the device wasn't unplugged */
@@ -522,7 +523,7 @@ static ssize_t adu_read(struct file *file, __user char *buffer, size_t count,
 
 exit:
         /* unlock the device */
-        up(&dev->sem);
+        mutex_unlock(&dev->mtx);
 
         dbg(2," %s : leave, return value %d", __FUNCTION__, retval);
         return retval;
@@ -543,7 +544,7 @@ static ssize_t adu_write(struct file *file, const __user char *buffer,
         dev = file->private_data;
 
         /* lock this object */
-        retval = down_interruptible(&dev->sem);
+        retval = mutex_lock_interruptible(&dev->mtx);
         if (retval)
                 goto exit_nolock;
 
@@ -571,9 +572,9 @@ static ssize_t adu_write(struct file *file, const __user char *buffer,
                                 retval = -EINTR;
                                 goto exit;
                         }
-                        up(&dev->sem);
+                        mutex_unlock(&dev->mtx);
                         timeout = interruptible_sleep_on_timeout(&dev->write_wait, timeout);
-                        retval = down_interruptible(&dev->sem);
+                        retval = mutex_lock_interruptible(&dev->mtx);
                         if (retval) {
                                 retval = bytes_written ? bytes_written : retval;
                                 goto exit_nolock;
@@ -638,7 +639,7 @@ static ssize_t adu_write(struct file *file, const __user char *buffer,
 
 exit:
         /* unlock the device */
-        up(&dev->sem);
+        mutex_unlock(&dev->mtx);
 exit_nolock:
 
         dbg(2," %s : leave, return value %d", __FUNCTION__, retval);
@@ -698,7 +699,7 @@ static int adu_probe(struct usb_interface *interface,
                 goto exit;
         }
 
-        init_MUTEX(&dev->sem);
+        mutex_init(&dev->mtx);
         spin_lock_init(&dev->buflock);
         dev->udev = udev;
         init_waitqueue_head(&dev->read_wait);
@@ -835,16 +836,16 @@ static void adu_disconnect(struct usb_interface *interface)
         usb_deregister_dev(interface, &adu_class);
         dev->minor = 0;
 
-        down(&dev->sem); /* not interruptible */
+        mutex_lock(&dev->mtx); /* not interruptible */
 
         /* if the device is not opened, then we clean up right now */
         dbg(2," %s : open count %d", __FUNCTION__, dev->open_count);
         if (!dev->open_count) {
-                up(&dev->sem);
+                mutex_unlock(&dev->mtx);
                 adu_delete(dev);
         } else {
                 dev->udev = NULL;
-                up(&dev->sem);
+                mutex_unlock(&dev->mtx);
         }
 
         dev_info(&interface->dev, "ADU device adutux%d now disconnected",