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>

1 files changed, 67 insertions, 45 deletions

diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index 401d76f13419..ca0e40ed2b72 100644
--- 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;