clockevents: Split out selection logic

Split out the clockevent device selection logic. Preparatory patch to
allow unbinding active clockevent devices.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Magnus Damm <magnus.damm@gmail.com>
Link: http://lkml.kernel.org/r/20130425143436.431796247@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index 0e374cd..d067c01 100644 (file)
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -65,19 +65,34 @@ static void tick_broadcast_start_periodic(struct clock_event_device *bc)
 /*
  * Check, if the device can be utilized as broadcast device:
  */
+static bool tick_check_broadcast_device(struct clock_event_device *curdev,
+                                       struct clock_event_device *newdev)
+{
+       if ((newdev->features & CLOCK_EVT_FEAT_DUMMY) ||
+           (newdev->features & CLOCK_EVT_FEAT_C3STOP))
+               return false;
+
+       if (tick_broadcast_device.mode == TICKDEV_MODE_ONESHOT &&
+           !(newdev->features & CLOCK_EVT_FEAT_ONESHOT))
+               return false;
+
+       return !curdev || newdev->rating > curdev->rating;
+}
+
+/*
+ * Conditionally install/replace broadcast device
+ */
 void tick_install_broadcast_device(struct clock_event_device *dev)
 {
        struct clock_event_device *cur = tick_broadcast_device.evtdev;
 
-       if ((dev->features & CLOCK_EVT_FEAT_DUMMY) ||
-           (tick_broadcast_device.evtdev &&
-            tick_broadcast_device.evtdev->rating >= dev->rating) ||
-            (dev->features & CLOCK_EVT_FEAT_C3STOP))
+       if (!tick_check_broadcast_device(cur, dev))
                return;
+
        if (!try_module_get(dev->owner))
                return;
 
-       clockevents_exchange_device(tick_broadcast_device.evtdev, dev);
+       clockevents_exchange_device(cur, dev);
        if (cur)
                cur->event_handler = clockevents_handle_noop;
        tick_broadcast_device.evtdev = dev;

diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index 433a1e1..c340216 100644 (file)
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -205,6 +205,37 @@ static void tick_setup_device(struct tick_device *td,
                tick_setup_oneshot(newdev, handler, next_event);
 }
 
+static bool tick_check_percpu(struct clock_event_device *curdev,
+                             struct clock_event_device *newdev, int cpu)
+{
+       if (!cpumask_test_cpu(cpu, newdev->cpumask))
+               return false;
+       if (cpumask_equal(newdev->cpumask, cpumask_of(cpu)))
+               return true;
+       /* Check if irq affinity can be set */
+       if (newdev->irq >= 0 && !irq_can_set_affinity(newdev->irq))
+               return false;
+       /* Prefer an existing cpu local device */
+       if (curdev && cpumask_equal(curdev->cpumask, cpumask_of(cpu)))
+               return false;
+       return true;
+}
+
+static bool tick_check_preferred(struct clock_event_device *curdev,
+                                struct clock_event_device *newdev)
+{
+       /* Prefer oneshot capable device */
+       if (!(newdev->features & CLOCK_EVT_FEAT_ONESHOT)) {
+               if (curdev && (curdev->features & CLOCK_EVT_FEAT_ONESHOT))
+                       return false;
+               if (tick_oneshot_mode_active())
+                       return false;
+       }
+
+       /* Use the higher rated one */
+       return !curdev || newdev->rating > curdev->rating;
+}
+
 /*
  * Check, if the new registered device should be used. Called with
  * clockevents_lock held and interrupts disabled.
@@ -223,40 +254,12 @@ void tick_check_new_device(struct clock_event_device *newdev)
        curdev = td->evtdev;
 
        /* cpu local device ? */
-       if (!cpumask_equal(newdev->cpumask, cpumask_of(cpu))) {
-
-               /*
-                * If the cpu affinity of the device interrupt can not
-                * be set, ignore it.
-                */
-               if (!irq_can_set_affinity(newdev->irq))
-                       goto out_bc;
-
-               /*
-                * If we have a cpu local device already, do not replace it
-                * by a non cpu local device
-                */
-               if (curdev && cpumask_equal(curdev->cpumask, cpumask_of(cpu)))
-                       goto out_bc;
-       }
+       if (!tick_check_percpu(curdev, newdev, cpu))
+               goto out_bc;
 
-       /*
-        * If we have an active device, then check the rating and the oneshot
-        * feature.
-        */
-       if (curdev) {
-               /*
-                * Prefer one shot capable devices !
-                */
-               if ((curdev->features & CLOCK_EVT_FEAT_ONESHOT) &&
-                   !(newdev->features & CLOCK_EVT_FEAT_ONESHOT))
-                       goto out_bc;
-               /*
-                * Check the rating
-                */
-               if (curdev->rating >= newdev->rating)
-                       goto out_bc;
-       }
+       /* Preference decision */
+       if (!tick_check_preferred(curdev, newdev))
+               goto out_bc;
 
        if (!try_module_get(newdev->owner))
                return;