Commit 1b3b38f8 authored by Andrew Morton's avatar Andrew Morton Committed by David Mosberger

[PATCH] clean up timer interpolation code

From: Christoph Hellwig <hch@lst.de>

- don't add one level of indentation when taking a lock

- remove useless ti_global struct
parent d8a2bcae
......@@ -1226,47 +1226,36 @@ void __init init_timers(void)
}
#ifdef CONFIG_TIME_INTERPOLATION
volatile unsigned long last_nsec_offset;
struct time_interpolator *time_interpolator;
#ifndef __HAVE_ARCH_CMPXCHG
spinlock_t last_nsec_offset_lock = SPIN_LOCK_UNLOCKED;
#endif
static struct {
spinlock_t lock; /* lock protecting list */
struct time_interpolator *list; /* list of registered interpolators */
} ti_global = {
.lock = SPIN_LOCK_UNLOCKED
};
struct time_interpolator *time_interpolator;
struct time_interpolator *time_interpolator_list;
spinlock_t time_interpolator_lock = SPIN_LOCK_UNLOCKED;
static inline int
is_better_time_interpolator(struct time_interpolator *new)
{
if (!time_interpolator)
return 1;
return new->frequency > 2*time_interpolator->frequency
|| (unsigned long) new->drift < (unsigned long) time_interpolator->drift;
return new->frequency > 2*time_interpolator->frequency ||
(unsigned long)new->drift < (unsigned long)time_interpolator->drift;
}
void
register_time_interpolator(struct time_interpolator *ti)
{
spin_lock(&ti_global.lock);
{
spin_lock(&time_interpolator_lock);
write_seqlock_irq(&xtime_lock);
{
if (is_better_time_interpolator(ti))
time_interpolator = ti;
}
write_sequnlock_irq(&xtime_lock);
ti->next = ti_global.list;
ti_global.list = ti;
}
spin_unlock(&ti_global.lock);
ti->next = time_interpolator_list;
time_interpolator_list = ti;
spin_unlock(&time_interpolator_lock);
}
void
......@@ -1274,9 +1263,8 @@ unregister_time_interpolator(struct time_interpolator *ti)
{
struct time_interpolator *curr, **prev;
spin_lock(&ti_global.lock);
{
prev = &ti_global.list;
spin_lock(&time_interpolator_lock);
prev = &time_interpolator_list;
for (curr = *prev; curr; curr = curr->next) {
if (curr == ti) {
*prev = curr->next;
......@@ -1284,20 +1272,17 @@ unregister_time_interpolator(struct time_interpolator *ti)
}
prev = &curr->next;
}
write_seqlock_irq(&xtime_lock);
{
if (ti == time_interpolator) {
/* we lost the best time-interpolator: */
time_interpolator = NULL;
/* find the next-best interpolator */
for (curr = ti_global.list; curr; curr = curr->next)
for (curr = time_interpolator_list; curr; curr = curr->next)
if (is_better_time_interpolator(curr))
time_interpolator = curr;
}
}
write_sequnlock_irq(&xtime_lock);
}
spin_unlock(&ti_global.lock);
spin_unlock(&time_interpolator_lock);
}
#endif /* CONFIG_TIME_INTERPOLATION */
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