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authorOliver Neukum <oneukum@suse.com>2019-10-16 15:20:30 +0200
committerOliver Neukum <oneukum@suse.com>2019-10-16 15:20:30 +0200
commitc88fa29d2e925bc88daa2dfaa1cfb747db758fd9 (patch)
tree59361d3f42472bb57d517ffe75029330f27785dc
parent48cf2531d674c5c180cee2cad7449f5781124220 (diff)
USB: legousbtower: fix deadlock on disconnect (bsc#1142635).
-rw-r--r--drivers/usb/misc/legousbtower.c19
1 files changed, 2 insertions, 17 deletions
diff --git a/drivers/usb/misc/legousbtower.c b/drivers/usb/misc/legousbtower.c
index e837097d34bc..84cf009a2546 100644
--- a/drivers/usb/misc/legousbtower.c
+++ b/drivers/usb/misc/legousbtower.c
@@ -185,7 +185,6 @@ static const struct usb_device_id tower_table[] = {
};
MODULE_DEVICE_TABLE (usb, tower_table);
-static DEFINE_MUTEX(open_disc_mutex);
#define LEGO_USB_TOWER_MINOR_BASE 160
@@ -338,18 +337,14 @@ static int tower_open (struct inode *inode, struct file *file)
goto exit;
}
- mutex_lock(&open_disc_mutex);
dev = usb_get_intfdata(interface);
-
if (!dev) {
- mutex_unlock(&open_disc_mutex);
retval = -ENODEV;
goto exit;
}
/* lock this device */
if (mutex_lock_interruptible(&dev->lock)) {
- mutex_unlock(&open_disc_mutex);
retval = -ERESTARTSYS;
goto exit;
}
@@ -357,12 +352,10 @@ static int tower_open (struct inode *inode, struct file *file)
/* allow opening only once */
if (dev->open_count) {
- mutex_unlock(&open_disc_mutex);
retval = -EBUSY;
goto unlock_exit;
}
dev->open_count = 1;
- mutex_unlock(&open_disc_mutex);
/* reset the tower */
result = usb_control_msg (dev->udev,
@@ -429,10 +422,9 @@ static int tower_release (struct inode *inode, struct file *file)
if (dev == NULL) {
retval = -ENODEV;
- goto exit_nolock;
+ goto exit;
}
- mutex_lock(&open_disc_mutex);
if (mutex_lock_interruptible(&dev->lock)) {
retval = -ERESTARTSYS;
goto exit;
@@ -462,10 +454,7 @@ static int tower_release (struct inode *inode, struct file *file)
unlock_exit:
mutex_unlock(&dev->lock);
-
exit:
- mutex_unlock(&open_disc_mutex);
-exit_nolock:
return retval;
}
@@ -917,7 +906,6 @@ static int tower_probe (struct usb_interface *interface, const struct usb_device
if (retval) {
/* something prevented us from registering this driver */
dev_err(idev, "Not able to get a minor for this device.\n");
- usb_set_intfdata (interface, NULL);
goto error;
}
dev->minor = interface->minor;
@@ -949,16 +937,13 @@ static void tower_disconnect (struct usb_interface *interface)
int minor;
dev = usb_get_intfdata (interface);
- mutex_lock(&open_disc_mutex);
- usb_set_intfdata (interface, NULL);
minor = dev->minor;
- /* give back our minor */
+ /* give back our minor and prevent further open() */
usb_deregister_dev (interface, &tower_class);
mutex_lock(&dev->lock);
- mutex_unlock(&open_disc_mutex);
/* if the device is not opened, then we clean up right now */
if (!dev->open_count) {