renegade-project/linux-next
2
0
Fork 0
mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-16 17:23:55 +08:00
Code

clockevents: prevent multiple init/shutdown

Browse Source 
While chasing the C1E/HPET bugreports I went through the clock events
code inch by inch and found that the broadcast device can be initialized
and shutdown multiple times. Multiple shutdowns are not critical, but
useless waste of time. Multiple initializations are simply broken. Another
CPU might have the device in use already after the first initialization and
the second init could just render it unusable again.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Thomas Gleixner 2008-09-03 21:37:08 +00:00
parent 7205656ab4
commit 9c17bcda99
1 changed files with 13 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
kernel/time/tick-broadcast.c
View File

@ -210,7 +210,7 @@ static void tick_do_broadcast_on_off(void *why)
struct clock_event_device *bc, *dev;
struct tick_device *td;
unsigned long flags, *reason = why;
int cpu;
int cpu, bc_stopped;
spin_lock_irqsave(&tick_broadcast_lock, flags);
@ -228,6 +228,8 @@ static void tick_do_broadcast_on_off(void *why)
if (!tick_device_is_functional(dev))
goto out;
bc_stopped = cpus_empty(tick_broadcast_mask);
switch (*reason) {
case CLOCK_EVT_NOTIFY_BROADCAST_ON:
case CLOCK_EVT_NOTIFY_BROADCAST_FORCE:
@ -250,9 +252,10 @@ static void tick_do_broadcast_on_off(void *why)
break;
}
if (cpus_empty(tick_broadcast_mask))
clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
else {
if (cpus_empty(tick_broadcast_mask)) {
if (!bc_stopped)
clockevents_set_mode(bc, CLOCK_EVT_MODE_SHUTDOWN);
} else if (bc_stopped) {
if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
tick_broadcast_start_periodic(bc);
else
@ -501,9 +504,12 @@ static void tick_broadcast_clear_oneshot(int cpu)
*/
void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
{
bc->event_handler = tick_handle_oneshot_broadcast;
clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
bc->next_event.tv64 = KTIME_MAX;
/* Set it up only once ! */
if (bc->event_handler != tick_handle_oneshot_broadcast) {
bc->event_handler = tick_handle_oneshot_broadcast;
clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
bc->next_event.tv64 = KTIME_MAX;
}
}
/*