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path: root/drivers/usb/usb-skeleton.c
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Diffstat (limited to 'drivers/usb/usb-skeleton.c')
-rw-r--r--drivers/usb/usb-skeleton.c40
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);
}