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

BugLink: https://bugs.launchpad.net/bugs/1850541
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>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

diff --git a/drivers/usb/usb-skeleton.c b/drivers/usb/usb-skeleton.c
index 26ca0ec01fd5a83479ffd4dd1e34008793656d4e..ba80bc099b3704956bad2c75e2b6e5d52ba911bb 100644 (file)
--- a/drivers/usb/usb-skeleton.c
+++ b/drivers/usb/usb-skeleton.c
@@ -71,6 +71,7 @@ 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);
@@ -122,10 +123,7 @@ 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);
@@ -503,7 +501,7 @@ 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 */