mdm6600: Wait for pending urbs on suspend

On suspend, while we are killing read urbs, some of the urbs
might succeed. Don't re-submit them and wait for the workqueue
to process them.

Fixed urbs ref count

Change-Id: I3c69926b0bec8d5425ed8bc403b8c040db5ab435
Signed-off-by: Benoit Goby <benoit@android.com>

diff --git a/drivers/usb/serial/mdm6600.c b/drivers/usb/serial/mdm6600.c
index 9b9805d7090e19c7ee39ed0a6ff18d2625a7e5a6..6ea24e2efb8b15b39c441d934973c74e5cd7079f 100644 (file)
--- a/drivers/usb/serial/mdm6600.c
+++ b/drivers/usb/serial/mdm6600.c
@@ -673,12 +673,25 @@ static void mdm6600_read_bulk_work(struct work_struct *work)
        size_t c;
        struct urb *u;
        struct tty_struct *tty;
+       unsigned long flags;
        struct mdm6600_port *modem = container_of(work, struct mdm6600_port,
                read.work);
+       struct usb_anchor *anchor = &modem->read.pending;
 
        dbg("%s", __func__);
 
-       while ((u = usb_get_from_anchor(&modem->read.pending))) {
+       while (true) {
+               spin_lock_irqsave(&anchor->lock, flags);
+               if (list_empty(&anchor->urb_list)) {
+                       spin_unlock_irqrestore(&anchor->lock, flags);
+                       return;
+               }
+
+               u = list_entry(anchor->urb_list.next, struct urb,
+                                   anchor_list);
+               usb_get_urb(u);
+               spin_unlock_irqrestore(&anchor->lock, flags);
+
                dbg("%s: processing urb %p len %u", __func__, u,
                        u->actual_length);
                usb_serial_debug_data(debug_data, &modem->port->dev, __func__,
@@ -697,7 +710,14 @@ static void mdm6600_read_bulk_work(struct work_struct *work)
                tty_kref_put(tty);
 
 next:
+               usb_unanchor_urb(u);
+               if (modem->susp_count) {
+                       usb_put_urb(u);
+                       continue;
+               }
+
                usb_anchor_urb(u, &modem->read.in_flight);
+               usb_put_urb(u);
                rc = usb_submit_urb(u, GFP_KERNEL);
                if (rc) {
                        pr_err("%s: Error %d re-submitting read urb %p\n",
@@ -759,6 +779,8 @@ static int mdm6600_suspend(struct usb_interface *intf, pm_message_t message)
                spin_unlock_irq(&modem->susp_lock);
                dbg("%s: kill urbs", __func__);
                mdm6600_kill_urbs(modem);
+               if (!usb_wait_anchor_empty_timeout(&modem->read.pending, 1000))
+                       usb_scuttle_anchored_urbs(&modem->read.pending);
                return 0;
        }
 
@@ -788,6 +810,7 @@ static int mdm6600_resume(struct usb_interface *intf)
 
                while ((u = usb_get_from_anchor(&modem->write.delayed))) {
                        usb_anchor_urb(u, &modem->write.in_flight);
+                       usb_put_urb(u);
                        rc = usb_submit_urb(u, GFP_KERNEL);
                        if (rc < 0) {
                                usb_unanchor_urb(u);