USB: usb-skeleton: fix runtime PM after driver unbind

commit 5c290a5e42c3387e82de86965784d30e6c5270fd upstream.

Since commit c2b71462d294 ("USB: core: Fix bug caused by duplicate
interface PM usage counter") USB drivers must always balance their
runtime PM gets and puts, including when the driver has already been
unbound from the interface.

Leaving the interface with a positive PM usage counter would prevent a
later bound driver from suspending the device.

Fixes: c2b71462d294 ("USB: core: Fix bug caused by duplicate interface PM usage counter")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20191001084908.2003-2-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/usb-skeleton.c b/drivers/usb/usb-skeleton.c
index 5133a0792eb0418391f74e4f56486731dc7e62fc..b8911b248315c4901e15738ac2f702abd480a4f1 100644 (file)
--- a/drivers/usb/usb-skeleton.c
+++ b/drivers/usb/usb-skeleton.c
@@ -75,6 +75,7 @@ static void skel_delete(struct kref *kref)
        struct usb_skel *dev = to_skel_dev(kref);
 
        usb_free_urb(dev->bulk_in_urb);
+       usb_put_intf(dev->interface);
        usb_put_dev(dev->udev);
        kfree(dev->bulk_in_buffer);
        kfree(dev);
@@ -126,10 +127,7 @@ static int skel_release(struct inode *inode, struct file *file)
                return -ENODEV;
 
        /* allow the device to be autosuspended */
-       mutex_lock(&dev->io_mutex);
-       if (dev->interface)
-               usb_autopm_put_interface(dev->interface);
-       mutex_unlock(&dev->io_mutex);
+       usb_autopm_put_interface(dev->interface);
 
        /* decrement the count on our device */
        kref_put(&dev->kref, skel_delete);
@@ -509,7 +507,7 @@ static int skel_probe(struct usb_interface *interface,
        init_waitqueue_head(&dev->bulk_in_wait);
 
        dev->udev = usb_get_dev(interface_to_usbdev(interface));
-       dev->interface = interface;
+       dev->interface = usb_get_intf(interface);
 
        /* set up the endpoint information */
        /* use only the first bulk-in and bulk-out endpoints */