USB: airprime: unlock mutex instead of trying to lock it again

[safe/jmp/linux-2.6] / drivers / usb / misc / idmouse.c

diff --git a/drivers/usb/misc/idmouse.c b/drivers/usb/misc/idmouse.c
index 15c70bd..4bcf7fb 100644 (file)
--- a/drivers/usb/misc/idmouse.c
+++ b/drivers/usb/misc/idmouse.c
@@ -22,7 +22,6 @@
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/module.h>
-#include <linux/smp_lock.h>
 #include <linux/completion.h>
 #include <linux/mutex.h>
 #include <asm/uaccess.h>
@@ -67,6 +66,7 @@ static struct usb_device_id idmouse_table[] = {
        USB_TYPE_VENDOR | USB_RECIP_ENDPOINT | USB_DIR_OUT, value, index, NULL, 0, 1000)
 
 MODULE_DEVICE_TABLE(usb, idmouse_table);
+static DEFINE_MUTEX(open_disc_mutex);
 
 /* structure to hold all of our device specific stuff */
 struct usb_idmouse {
@@ -81,7 +81,7 @@ struct usb_idmouse {
 
        int open; /* if the port is open or not */
        int present; /* if the device is not disconnected */
-       struct semaphore sem; /* locks this structure */
+       struct mutex lock; /* locks this structure */
 
 };
 
@@ -120,9 +120,6 @@ static struct usb_driver idmouse_driver = {
        .id_table = idmouse_table,
 };
 
-/* prevent races between open() and disconnect() */
-static DEFINE_MUTEX(disconnect_mutex);
-
 static int idmouse_create_image(struct usb_idmouse *dev)
 {
        int bytes_read;
@@ -212,24 +209,22 @@ static int idmouse_open(struct inode *inode, struct file *file)
        struct usb_interface *interface;
        int result;
 
-       /* prevent disconnects */
-       mutex_lock(&disconnect_mutex);
-
        /* get the interface from minor number and driver information */
        interface = usb_find_interface (&idmouse_driver, iminor (inode));
-       if (!interface) {
-               mutex_unlock(&disconnect_mutex);
+       if (!interface)
                return -ENODEV;
-       }
+
+       mutex_lock(&open_disc_mutex);
        /* get the device information block from the interface */
        dev = usb_get_intfdata(interface);
        if (!dev) {
-               mutex_unlock(&disconnect_mutex);
+               mutex_unlock(&open_disc_mutex);
                return -ENODEV;
        }
 
        /* lock this device */
-       down(&dev->sem);
+       mutex_lock(&dev->lock);
+       mutex_unlock(&open_disc_mutex);
 
        /* check if already open */
        if (dev->open) {
@@ -255,10 +250,7 @@ static int idmouse_open(struct inode *inode, struct file *file)
 error:
 
        /* unlock this device */
-       up(&dev->sem);
-
-       /* unlock the disconnect semaphore */
-       mutex_unlock(&disconnect_mutex);
+       mutex_unlock(&dev->lock);
        return result;
 }
 
@@ -266,23 +258,19 @@ static int idmouse_release(struct inode *inode, struct file *file)
 {
        struct usb_idmouse *dev;
 
-       /* prevent a race condition with open() */
-       mutex_lock(&disconnect_mutex);
-
        dev = file->private_data;
 
-       if (dev == NULL) {
-               mutex_unlock(&disconnect_mutex);
+       if (dev == NULL)
                return -ENODEV;
-       }
 
+       mutex_lock(&open_disc_mutex);
        /* lock our device */
-       down(&dev->sem);
+       mutex_lock(&dev->lock);
 
        /* are we really open? */
        if (dev->open <= 0) {
-               up(&dev->sem);
-               mutex_unlock(&disconnect_mutex);
+               mutex_unlock(&dev->lock);
+               mutex_unlock(&open_disc_mutex);
                return -ENODEV;
        }
 
@@ -290,14 +278,13 @@ static int idmouse_release(struct inode *inode, struct file *file)
 
        if (!dev->present) {
                /* the device was unplugged before the file was released */
-               up(&dev->sem);
+               mutex_unlock(&dev->lock);
+               mutex_unlock(&open_disc_mutex);
                idmouse_delete(dev);
-               mutex_unlock(&disconnect_mutex);
-               return 0;
+       } else {
+               mutex_unlock(&dev->lock);
+               mutex_unlock(&open_disc_mutex);
        }
-
-       up(&dev->sem);
-       mutex_unlock(&disconnect_mutex);
        return 0;
 }
 
@@ -308,18 +295,18 @@ static ssize_t idmouse_read(struct file *file, char __user *buffer, size_t count
        int result;
 
        /* lock this object */
-       down(&dev->sem);
+       mutex_lock(&dev->lock);
 
        /* verify that the device wasn't unplugged */
        if (!dev->present) {
-               up(&dev->sem);
+               mutex_unlock(&dev->lock);
                return -ENODEV;
        }
 
        result = simple_read_from_buffer(buffer, count, ppos,
                                        dev->bulk_in_buffer, IMGSIZE);
        /* unlock the device */
-       up(&dev->sem);
+       mutex_unlock(&dev->lock);
        return result;
 }
 
@@ -342,7 +329,7 @@ static int idmouse_probe(struct usb_interface *interface,
        if (dev == NULL)
                return -ENOMEM;
 
-       init_MUTEX(&dev->sem);
+       mutex_init(&dev->lock);
        dev->udev = udev;
        dev->interface = interface;
 
@@ -392,30 +379,29 @@ static void idmouse_disconnect(struct usb_interface *interface)
 {
        struct usb_idmouse *dev;
 
-       /* prevent races with open() */
-       mutex_lock(&disconnect_mutex);
-
        /* get device structure */
        dev = usb_get_intfdata(interface);
-       usb_set_intfdata(interface, NULL);
-
-       /* lock it */
-       down(&dev->sem);
 
        /* give back our minor */
        usb_deregister_dev(interface, &idmouse_class);
 
+       mutex_lock(&open_disc_mutex);
+       usb_set_intfdata(interface, NULL);
+       /* lock the device */
+       mutex_lock(&dev->lock);
+       mutex_unlock(&open_disc_mutex);
+
        /* prevent device read, write and ioctl */
        dev->present = 0;
 
-       /* unlock */
-       up(&dev->sem);
-
        /* if the device is opened, idmouse_release will clean this up */
-       if (!dev->open)
+       if (!dev->open) {
+               mutex_unlock(&dev->lock);
                idmouse_delete(dev);
-
-       mutex_unlock(&disconnect_mutex);
+       } else {
+               /* unlock */
+               mutex_unlock(&dev->lock);
+       }
 
        info("%s disconnected", DRIVER_DESC);
 }