USB: fix signed jiffies issue in autosuspend logic

This patch (as897) changes the autosuspend timer code to use the
standard types and macros in dealing with jiffies values.

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 631f305..b9f7f90 100644 (file)
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -932,7 +932,7 @@ static int autosuspend_check(struct usb_device *udev)
 {
        int                     i;
        struct usb_interface    *intf;
-       long                    suspend_time;
+       unsigned long           suspend_time;
 
        /* For autosuspend, fail fast if anything is in use or autosuspend
         * is disabled.  Also fail if any interfaces require remote wakeup
@@ -964,11 +964,18 @@ static int autosuspend_check(struct usb_device *udev)
        /* If everything is okay but the device hasn't been idle for long
         * enough, queue a delayed autosuspend request.
         */
-       suspend_time -= jiffies;
-       if (suspend_time > 0) {
-               if (!timer_pending(&udev->autosuspend.timer))
+       if (time_after(suspend_time, jiffies)) {
+               if (!timer_pending(&udev->autosuspend.timer)) {
+
+                       /* The value of jiffies may change between the
+                        * time_after() comparison above and the subtraction
+                        * below.  That's okay; the system behaves sanely
+                        * when a timer is registered for the present moment
+                        * or for the past.
+                        */
                        queue_delayed_work(ksuspend_usb_wq, &udev->autosuspend,
-                                       suspend_time);
+                                       suspend_time - jiffies);
+                       }
                return -EAGAIN;
        }
        return 0;