[PATCH 3.10 47/58] clockevents: Split out selection logic

Greg Kroah-Hartman
2013-12-06T22:06:35Z

From: Thomas Gleixner <tglx@linutronix.de>

commit 45cb8e01b2ecef1c2afb18333e95793fa1a90281 upstream.

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>
Cc: Kim Phillips <kim.phillips@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
kernel/time/tick-broadcast.c | 25 ++++++++++++---
kernel/time/tick-common.c | 69 ++++++++++++++++++++++---------------------
2 files changed, 56 insertions(+), 38 deletions(-)

--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -66,19 +66,34 @@ static void tick_broadcast_start_periodi
/*
* 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;
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -207,6 +207,37 @@ static void tick_setup_device(struct tic
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.
*/
@@ -227,40 +258,12 @@ void tick_check_new_device(struct clock_
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;