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Commit 8293c568 authored by Matthias Kaehlcke's avatar Matthias Kaehlcke Committed by Greg Kroah-Hartman
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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: default avatarMatthias Kaehlcke <matthias.kaehlcke@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent d2066eb6

drivers/usb/misc/adutux.c

+18 −17
Original line number Diff line number Diff line
@@ -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",