USB: autosuspend code consolidation

This patch (as813) gathers together common code for USB interface
autosuspend/autoresume.

It also adds some simple checking at the time an autosuspend request
is made, to see whether the request will fail.  This way we don't
add a workqueue entry when it would end up doing nothing.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index 401d76f..ca0e40e 100644 (file)
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -940,6 +940,36 @@ done:
        return status;
 }
 
+/* Internal routine to check whether we may autosuspend a device. */
+static int autosuspend_check(struct usb_device *udev)
+{
+       int                     i;
+       struct usb_interface    *intf;
+
+       /* For autosuspend, fail fast if anything is in use.
+        * Also fail if any interfaces require remote wakeup but it
+        * isn't available. */
+       udev->do_remote_wakeup = device_may_wakeup(&udev->dev);
+       if (udev->pm_usage_cnt > 0)
+               return -EBUSY;
+       if (udev->actconfig) {
+               for (i = 0; i < udev->actconfig->desc.bNumInterfaces; i++) {
+                       intf = udev->actconfig->interface[i];
+                       if (!is_active(intf))
+                               continue;
+                       if (intf->pm_usage_cnt > 0)
+                               return -EBUSY;
+                       if (intf->needs_remote_wakeup &&
+                                       !udev->do_remote_wakeup) {
+                               dev_dbg(&udev->dev, "remote wakeup needed "
+                                               "for autosuspend\n");
+                               return -EOPNOTSUPP;
+                       }
+               }
+       }
+       return 0;
+}
+
 /**
  * usb_suspend_both - suspend a USB device and its interfaces
  * @udev: the usb_device to suspend
@@ -991,28 +1021,10 @@ int usb_suspend_both(struct usb_device *udev, pm_message_t msg)
 
        udev->do_remote_wakeup = device_may_wakeup(&udev->dev);
 
-       /* For autosuspend, fail fast if anything is in use.
-        * Also fail if any interfaces require remote wakeup but it
-        * isn't available. */
        if (udev->auto_pm) {
-               if (udev->pm_usage_cnt > 0)
-                       return -EBUSY;
-               if (udev->actconfig) {
-                       for (; i < udev->actconfig->desc.bNumInterfaces; i++) {
-                               intf = udev->actconfig->interface[i];
-                               if (!is_active(intf))
-                                       continue;
-                               if (intf->pm_usage_cnt > 0)
-                                       return -EBUSY;
-                               if (intf->needs_remote_wakeup &&
-                                               !udev->do_remote_wakeup) {
-                                       dev_dbg(&udev->dev,
-       "remote wakeup needed for autosuspend\n");
-                                       return -EOPNOTSUPP;
-                               }
-                       }
-                       i = 0;
-               }
+               status = autosuspend_check(udev);
+               if (status < 0)
+                       return status;
        }
 
        /* Suspend all the interfaces and then udev itself */
@@ -1151,7 +1163,7 @@ void usb_autosuspend_device(struct usb_device *udev, int dec_usage_cnt)
 {
        usb_pm_lock(udev);
        udev->pm_usage_cnt -= dec_usage_cnt;
-       if (udev->pm_usage_cnt <= 0)
+       if (autosuspend_check(udev) == 0)
                queue_delayed_work(ksuspend_usb_wq, &udev->autosuspend,
                                USB_AUTOSUSPEND_DELAY);
        usb_pm_unlock(udev);
@@ -1200,6 +1212,33 @@ int usb_autoresume_device(struct usb_device *udev, int inc_usage_cnt)
        return status;
 }
 
+/* Internal routine to adjust an interface's usage counter and change
+ * its device's autosuspend state.
+ */
+static int usb_autopm_do_interface(struct usb_interface *intf,
+               int inc_usage_cnt)
+{
+       struct usb_device       *udev = interface_to_usbdev(intf);
+       int                     status = 0;
+
+       usb_pm_lock(udev);
+       if (intf->condition == USB_INTERFACE_UNBOUND)
+               status = -ENODEV;
+       else {
+               intf->pm_usage_cnt += inc_usage_cnt;
+               if (inc_usage_cnt >= 0 && intf->pm_usage_cnt > 0) {
+                       udev->auto_pm = 1;
+                       status = usb_resume_both(udev);
+                       if (status != 0)
+                               intf->pm_usage_cnt -= inc_usage_cnt;
+               } else if (inc_usage_cnt <= 0 && autosuspend_check(udev) == 0)
+                       queue_delayed_work(ksuspend_usb_wq, &udev->autosuspend,
+                                       USB_AUTOSUSPEND_DELAY);
+       }
+       usb_pm_unlock(udev);
+       return status;
+}
+
 /**
  * usb_autopm_put_interface - decrement a USB interface's PM-usage counter
  * @intf: the usb_interface whose counter should be decremented
@@ -1233,17 +1272,11 @@ int usb_autoresume_device(struct usb_device *udev, int inc_usage_cnt)
  */
 void usb_autopm_put_interface(struct usb_interface *intf)
 {
-       struct usb_device       *udev = interface_to_usbdev(intf);
+       int     status;
 
-       usb_pm_lock(udev);
-       if (intf->condition != USB_INTERFACE_UNBOUND &&
-                       --intf->pm_usage_cnt <= 0) {
-               queue_delayed_work(ksuspend_usb_wq, &udev->autosuspend,
-                               USB_AUTOSUSPEND_DELAY);
-       }
-       usb_pm_unlock(udev);
-       // dev_dbg(&intf->dev, "%s: cnt %d\n",
-       //              __FUNCTION__, intf->pm_usage_cnt);
+       status = usb_autopm_do_interface(intf, -1);
+       // dev_dbg(&intf->dev, "%s: status %d cnt %d\n",
+       //              __FUNCTION__, status, intf->pm_usage_cnt);
 }
 EXPORT_SYMBOL_GPL(usb_autopm_put_interface);
 
@@ -1280,20 +1313,9 @@ EXPORT_SYMBOL_GPL(usb_autopm_put_interface);
  */
 int usb_autopm_get_interface(struct usb_interface *intf)
 {
-       struct usb_device       *udev = interface_to_usbdev(intf);
-       int                     status;
+       int     status;
 
-       usb_pm_lock(udev);
-       if (intf->condition == USB_INTERFACE_UNBOUND)
-               status = -ENODEV;
-       else {
-               ++intf->pm_usage_cnt;
-               udev->auto_pm = 1;
-               status = usb_resume_both(udev);
-               if (status != 0)
-                       --intf->pm_usage_cnt;
-       }
-       usb_pm_unlock(udev);
+       status = usb_autopm_do_interface(intf, 1);
        // dev_dbg(&intf->dev, "%s: status %d cnt %d\n",
        //              __FUNCTION__, status, intf->pm_usage_cnt);
        return status;