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ntp: Add ntp_lock to replace xtime_locking

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Use a ntp_lock spin lock to replace xtime_lock locking in ntp.c

CC: Thomas Gleixner <tglx@linutronix.de>
CC: Eric Dumazet <eric.dumazet@gmail.com>
CC: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
This commit is contained in:
John Stultz 2011-11-14 13:48:36 -08:00
parent ea7cf49a76
commit bd3312681f
1 changed files with 44 additions and 19 deletions
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63
kernel/time/ntp.c
View file

@ -22,6 +22,9 @@
* NTP timekeeping variables:
*/
DEFINE_SPINLOCK(ntp_lock);
/* USER_HZ period (usecs): */
unsigned long tick_usec = TICK_USEC;
@ -133,7 +136,7 @@ static inline void pps_reset_freq_interval(void)
/**
* pps_clear - Clears the PPS state variables
*
* Must be called while holding a write on the xtime_lock
* Must be called while holding a write on the ntp_lock
*/
static inline void pps_clear(void)
{
@ -149,7 +152,7 @@ static inline void pps_clear(void)
* the last PPS signal. When it reaches 0, indicate that PPS signal is
* missing.
*
* Must be called while holding a write on the xtime_lock
* Must be called while holding a write on the ntp_lock
*/
static inline void pps_dec_valid(void)
{
@ -341,11 +344,13 @@ static void ntp_update_offset(long offset)
/**
* ntp_clear - Clears the NTP state variables
*
* Must be called while holding a write on the xtime_lock
*/
void ntp_clear(void)
{
unsigned long flags;
spin_lock_irqsave(&ntp_lock, flags);
time_adjust = 0; /* stop active adjtime() */
time_status |= STA_UNSYNC;
time_maxerror = NTP_PHASE_LIMIT;
@ -358,12 +363,20 @@ void ntp_clear(void)
/* Clear PPS state variables */
pps_clear();
spin_unlock_irqrestore(&ntp_lock, flags);
}
u64 ntp_tick_length(void)
{
return tick_length;
unsigned long flags;
s64 ret;
spin_lock_irqsave(&ntp_lock, flags);
ret = tick_length;
spin_unlock_irqrestore(&ntp_lock, flags);
return ret;
}
@ -375,14 +388,15 @@ u64 ntp_tick_length(void)
static enum hrtimer_restart ntp_leap_second(struct hrtimer *timer)
{
enum hrtimer_restart res = HRTIMER_NORESTART;
unsigned long flags;
int leap = 0;
write_seqlock(&xtime_lock);
spin_lock_irqsave(&ntp_lock, flags);
switch (time_state) {
case TIME_OK:
break;
case TIME_INS:
timekeeping_leap_insert(-1);
leap = -1;
time_state = TIME_OOP;
printk(KERN_NOTICE
"Clock: inserting leap second 23:59:60 UTC\n");
@ -390,7 +404,7 @@ static enum hrtimer_restart ntp_leap_second(struct hrtimer *timer)
res = HRTIMER_RESTART;
break;
case TIME_DEL:
timekeeping_leap_insert(1);
leap = 1;
time_tai--;
time_state = TIME_WAIT;
printk(KERN_NOTICE
@ -405,8 +419,14 @@ static enum hrtimer_restart ntp_leap_second(struct hrtimer *timer)
time_state = TIME_OK;
break;
}
spin_unlock_irqrestore(&ntp_lock, flags);
write_sequnlock(&xtime_lock);
/*
* We have to call this outside of the ntp_lock to keep
* the proper locking hierarchy
*/
if (leap)
timekeeping_leap_insert(leap);
return res;
}
@ -422,6 +442,9 @@ static enum hrtimer_restart ntp_leap_second(struct hrtimer *timer)
void second_overflow(void)
{
s64 delta;
unsigned long flags;
spin_lock_irqsave(&ntp_lock, flags);
/* Bump the maxerror field */
time_maxerror += MAXFREQ / NSEC_PER_USEC;
@ -441,23 +464,25 @@ void second_overflow(void)
pps_dec_valid();
if (!time_adjust)
return;
goto out;
if (time_adjust > MAX_TICKADJ) {
time_adjust -= MAX_TICKADJ;
tick_length += MAX_TICKADJ_SCALED;
return;
goto out;
}
if (time_adjust < -MAX_TICKADJ) {
time_adjust += MAX_TICKADJ;
tick_length -= MAX_TICKADJ_SCALED;
return;
goto out;
}
tick_length += (s64)(time_adjust * NSEC_PER_USEC / NTP_INTERVAL_FREQ)
<< NTP_SCALE_SHIFT;
time_adjust = 0;
out:
spin_unlock_irqrestore(&ntp_lock, flags);
}
#ifdef CONFIG_GENERIC_CMOS_UPDATE
@ -681,7 +706,7 @@ int do_adjtimex(struct timex *txc)
getnstimeofday(&ts);
write_seqlock_irq(&xtime_lock);
spin_lock_irq(&ntp_lock);
if (txc->modes & ADJ_ADJTIME) {
long save_adjust = time_adjust;
@ -723,7 +748,7 @@ int do_adjtimex(struct timex *txc)
/* fill PPS status fields */
pps_fill_timex(txc);
write_sequnlock_irq(&xtime_lock);
spin_unlock_irq(&ntp_lock);
txc->time.tv_sec = ts.tv_sec;
txc->time.tv_usec = ts.tv_nsec;
@ -921,7 +946,7 @@ void hardpps(const struct timespec *phase_ts, const struct timespec *raw_ts)
pts_norm = pps_normalize_ts(*phase_ts);
write_seqlock_irqsave(&xtime_lock, flags);
spin_lock_irqsave(&ntp_lock, flags);
/* clear the error bits, they will be set again if needed */
time_status &= ~(STA_PPSJITTER | STA_PPSWANDER | STA_PPSERROR);
@ -934,7 +959,7 @@ void hardpps(const struct timespec *phase_ts, const struct timespec *raw_ts)
* just start the frequency interval */
if (unlikely(pps_fbase.tv_sec == 0)) {
pps_fbase = *raw_ts;
write_sequnlock_irqrestore(&xtime_lock, flags);
spin_unlock_irqrestore(&ntp_lock, flags);
return;
}
@ -949,7 +974,7 @@ void hardpps(const struct timespec *phase_ts, const struct timespec *raw_ts)
time_status |= STA_PPSJITTER;
/* restart the frequency calibration interval */
pps_fbase = *raw_ts;
write_sequnlock_irqrestore(&xtime_lock, flags);
spin_unlock_irqrestore(&ntp_lock, flags);
pr_err("hardpps: PPSJITTER: bad pulse\n");
return;
}
@ -966,7 +991,7 @@ void hardpps(const struct timespec *phase_ts, const struct timespec *raw_ts)
hardpps_update_phase(pts_norm.nsec);
write_sequnlock_irqrestore(&xtime_lock, flags);
spin_unlock_irqrestore(&ntp_lock, flags);
}
EXPORT_SYMBOL(hardpps);