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

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 c31d17d05810c933f3098187023627d28e2ea61d..8001d6384c73f4712a1f004385e84465e4865f20 100644 (file)
--- a/drivers/usb/usb-skeleton.c
+++ b/drivers/usb/usb-skeleton.c
@@ -73,6 +73,7 @@ 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);
@@ -124,10 +125,7 @@ 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);
@@ -507,7 +505,7 @@ 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 */