1 files changed, 30 insertions, 2 deletions

diff --git a/drivers/usb/gadget/udc/dummy_hcd.c b/drivers/usb/gadget/udc/dummy_hcd.c
index b2ab9cc33fec..b17618a55f1b 100644
--- a/drivers/usb/gadget/udc/dummy_hcd.c
+++ b/drivers/usb/gadget/udc/dummy_hcd.c
@@ -255,11 +255,13 @@ struct dummy {
          */
         struct dummy_ep                 ep[DUMMY_ENDPOINTS];
         int                             address;
+        int                             callback_usage;
         struct usb_gadget               gadget;
         struct usb_gadget_driver        *driver;
         struct dummy_request            fifo_req;
         u8                              fifo_buf[FIFO_SIZE];
         u16                             devstatus;
+        unsigned                        ints_enabled:1;
         unsigned                        udc_suspended:1;
         unsigned                        pullup:1;
 
@@ -441,18 +443,27 @@ static void set_link_state(struct dummy_hcd *dum_hcd)
                                 (~dum_hcd->old_status) & dum_hcd->port_status;
 
                 /* Report reset and disconnect events to the driver */
-                if (dum->driver && (disconnect || reset)) {
+                if (dum->ints_enabled && (disconnect || reset)) {
                         stop_activity(dum);
+                        ++dum->callback_usage;
+                        spin_unlock(&dum->lock);
                         if (reset)
                                 usb_gadget_udc_reset(&dum->gadget, dum->driver);
                         else
                                 dum->driver->disconnect(&dum->gadget);
+                        spin_lock(&dum->lock);
+                        --dum->callback_usage;
                 }
-        } else if (dum_hcd->active != dum_hcd->old_active) {
+        } else if (dum_hcd->active != dum_hcd->old_active &&
+                        dum->ints_enabled) {
+                ++dum->callback_usage;
+                spin_unlock(&dum->lock);
                 if (dum_hcd->old_active && dum->driver->suspend)
                         dum->driver->suspend(&dum->gadget);
                 else if (!dum_hcd->old_active &&  dum->driver->resume)
                         dum->driver->resume(&dum->gadget);
+                spin_lock(&dum->lock);
+                --dum->callback_usage;
         }
 
         dum_hcd->old_status = dum_hcd->port_status;
@@ -973,8 +984,11 @@ static int dummy_udc_start(struct usb_gadget *g,
          * can't enumerate without help from the driver we're binding.
          */
 
+        spin_lock_irq(&dum->lock);
         dum->devstatus = 0;
         dum->driver = driver;
+        dum->ints_enabled = 1;
+        spin_unlock_irq(&dum->lock);
 
         return 0;
 }
@@ -985,6 +999,16 @@ static int dummy_udc_stop(struct usb_gadget *g)
         struct dummy            *dum = dum_hcd->dum;
 
         spin_lock_irq(&dum->lock);
+        dum->ints_enabled = 0;
+        stop_activity(dum);
+
+        /* emulate synchronize_irq(): wait for callbacks to finish */
+        while (dum->callback_usage > 0) {
+                spin_unlock_irq(&dum->lock);
+                usleep_range(1000, 2000);
+                spin_lock_irq(&dum->lock);
+        }
+
         dum->driver = NULL;
         spin_unlock_irq(&dum->lock);
 
@@ -1529,6 +1553,8 @@ static struct dummy_ep *find_endpoint(struct dummy *dum, u8 address)
         if (!is_active((dum->gadget.speed == USB_SPEED_SUPER ?
                         dum->ss_hcd : dum->hs_hcd)))
                 return NULL;
+        if (!dum->ints_enabled)
+                return NULL;
         if ((address & ~USB_DIR_IN) == 0)
                 return &dum->ep[0];
         for (i = 1; i < DUMMY_ENDPOINTS; i++) {
@@ -1870,10 +1896,12 @@ restart:
                          * until setup() returns; no reentrancy issues etc.
                          */
                         if (value > 0) {
+                                ++dum->callback_usage;
                                 spin_unlock(&dum->lock);
                                 value = dum->driver->setup(&dum->gadget,
                                                 &setup);
                                 spin_lock(&dum->lock);
+                                --dum->callback_usage;
 
                                 if (value >= 0) {
                                         /* no delays (max 64KB data stage) */