usb: cdc-wdm: Fix order in disconnect and fix locking

- as the callback can schedule work, URBs must be killed first
- if the driver causes an autoresume, the caller must handle locking

Signed-off-by: Oliver Neukum <neukum@b1-systems.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 17 insertions, 8 deletions

diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c
index 07c12974fe14..b57490508860 100644
--- a/drivers/usb/class/cdc-wdm.c
+++ b/drivers/usb/class/cdc-wdm.c
@@ -776,9 +776,9 @@ static void wdm_disconnect(struct usb_interface *intf)
         /* to terminate pending flushes */
         clear_bit(WDM_IN_USE, &desc->flags);
         spin_unlock_irqrestore(&desc->iuspin, flags);
-        cancel_work_sync(&desc->rxwork);
         mutex_lock(&desc->lock);
         kill_urbs(desc);
+        cancel_work_sync(&desc->rxwork);
         mutex_unlock(&desc->lock);
         wake_up_all(&desc->wait);
         if (!desc->count)
@@ -786,6 +786,7 @@ static void wdm_disconnect(struct usb_interface *intf)
         mutex_unlock(&wdm_mutex);
 }
 
+#ifdef CONFIG_PM
 static int wdm_suspend(struct usb_interface *intf, pm_message_t message)
 {
         struct wdm_device *desc = usb_get_intfdata(intf);
@@ -793,27 +794,30 @@ static int wdm_suspend(struct usb_interface *intf, pm_message_t message)
 
         dev_dbg(&desc->intf->dev, "wdm%d_suspend\n", intf->minor);
 
-        mutex_lock(&desc->lock);
+        /* if this is an autosuspend the caller does the locking */
+        if (!(message.event & PM_EVENT_AUTO))
+                mutex_lock(&desc->lock);
         spin_lock_irq(&desc->iuspin);
-#ifdef CONFIG_PM
+
         if ((message.event & PM_EVENT_AUTO) &&
                         (test_bit(WDM_IN_USE, &desc->flags)
                         || test_bit(WDM_RESPONDING, &desc->flags))) {
                 spin_unlock_irq(&desc->iuspin);
                 rv = -EBUSY;
         } else {
-#endif
+
                 set_bit(WDM_SUSPENDING, &desc->flags);
                 spin_unlock_irq(&desc->iuspin);
-                cancel_work_sync(&desc->rxwork);
+                /* callback submits work - order is essential */
                 kill_urbs(desc);
-#ifdef CONFIG_PM
+                cancel_work_sync(&desc->rxwork);
         }
-#endif
-        mutex_unlock(&desc->lock);
+        if (!(message.event & PM_EVENT_AUTO))
+                mutex_unlock(&desc->lock);
 
         return rv;
 }
+#endif
 
 static int recover_from_urb_loss(struct wdm_device *desc)
 {
@@ -827,6 +831,8 @@ static int recover_from_urb_loss(struct wdm_device *desc)
         }
         return rv;
 }
+
+#ifdef CONFIG_PM
 static int wdm_resume(struct usb_interface *intf)
 {
         struct wdm_device *desc = usb_get_intfdata(intf);
@@ -839,6 +845,7 @@ static int wdm_resume(struct usb_interface *intf)
         mutex_unlock(&desc->lock);
         return rv;
 }
+#endif
 
 static int wdm_pre_reset(struct usb_interface *intf)
 {
@@ -862,9 +869,11 @@ static struct usb_driver wdm_driver = {
         .name =         "cdc_wdm",
         .probe =        wdm_probe,
         .disconnect =   wdm_disconnect,
+#ifdef CONFIG_PM
         .suspend =      wdm_suspend,
         .resume =       wdm_resume,
         .reset_resume = wdm_resume,
+#endif
         .pre_reset =    wdm_pre_reset,
         .post_reset =   wdm_post_reset,
         .id_table =     wdm_ids,