1 files changed, 21 insertions, 19 deletions

diff --git a/drivers/usb/usb-skeleton.c b/drivers/usb/usb-skeleton.c
index 5c6c1bdbd455..8efeae24764f 100644
--- a/drivers/usb/usb-skeleton.c
+++ b/drivers/usb/usb-skeleton.c
@@ -27,6 +27,8 @@
 #define USB_SKEL_VENDOR_ID	0xfff0
 #define USB_SKEL_PRODUCT_ID	0xfff0
 
+static DEFINE_MUTEX(skel_mutex);
+
 /* table of devices that work with this driver */
 static const struct usb_device_id skel_table[] = {
 	{ USB_DEVICE(USB_SKEL_VENDOR_ID, USB_SKEL_PRODUCT_ID) },
@@ -60,7 +62,6 @@ struct usb_skel {
 	__u8			bulk_in_endpointAddr;	/* the address of the bulk in endpoint */
 	__u8			bulk_out_endpointAddr;	/* the address of the bulk out endpoint */
 	int			errors;			/* the last request tanked */
-	int			open_count;		/* count the number of openers */
 	bool			ongoing_read;		/* a read is going on */
 	bool			processed_urb;		/* indicates we haven't processed the urb */
 	spinlock_t		err_lock;		/* lock for errors */
@@ -100,39 +101,37 @@ static int skel_open(struct inode *inode, struct file *file)
 		goto exit;
 	}
 
+	mutex_lock(&skel_mutex);
 	dev = usb_get_intfdata(interface);
 	if (!dev) {
+		mutex_unlock(&skel_mutex);
 		retval = -ENODEV;
 		goto exit;
 	}
 
 	/* increment our usage count for the device */
 	kref_get(&dev->kref);
+	mutex_unlock(&skel_mutex);
 
 	/* lock the device to allow correctly handling errors
 	 * in resumption */
 	mutex_lock(&dev->io_mutex);
+	if (!dev->interface) {
+		retval = -ENODEV;
+		goto out_err;
+	}
 
-	if (!dev->open_count++) {
-		retval = usb_autopm_get_interface(interface);
-			if (retval) {
-				dev->open_count--;
-				mutex_unlock(&dev->io_mutex);
-				kref_put(&dev->kref, skel_delete);
-				goto exit;
-			}
-	} /* else { //uncomment this block if you want exclusive open
-		retval = -EBUSY;
-		dev->open_count--;
-		mutex_unlock(&dev->io_mutex);
-		kref_put(&dev->kref, skel_delete);
-		goto exit;
-	} */
-	/* prevent the device from being autosuspended */
+	retval = usb_autopm_get_interface(interface);
+	if (retval)
+		goto out_err;
 
 	/* save our object in the file's private structure */
 	file->private_data = dev;
+
+out_err:
 	mutex_unlock(&dev->io_mutex);
+	if (retval)
+		kref_put(&dev->kref, skel_delete);
 
 exit:
 	return retval;
@@ -148,7 +147,7 @@ static int skel_release(struct inode *inode, struct file *file)
 
 	/* allow the device to be autosuspended */
 	mutex_lock(&dev->io_mutex);
-	if (!--dev->open_count && dev->interface)
+	if (dev->interface)
 		usb_autopm_put_interface(dev->interface);
 	mutex_unlock(&dev->io_mutex);
 
@@ -612,7 +611,6 @@ static void skel_disconnect(struct usb_interface *interface)
 	int minor = interface->minor;
 
 	dev = usb_get_intfdata(interface);
-	usb_set_intfdata(interface, NULL);
 
 	/* give back our minor */
 	usb_deregister_dev(interface, &skel_class);
@@ -624,8 +622,12 @@ static void skel_disconnect(struct usb_interface *interface)
 
 	usb_kill_anchored_urbs(&dev->submitted);
 
+	mutex_lock(&skel_mutex);
+	usb_set_intfdata(interface, NULL);
+
 	/* decrement our usage count */
 	kref_put(&dev->kref, skel_delete);
+	mutex_unlock(&skel_mutex);
 
 	dev_info(&interface->dev, "USB Skeleton #%d now disconnected", minor);
 }