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Subject[PATCH 3/5] cleanups ntp.c (from Ingo)
From
Date
Make this file more readable by applying a consistent coding style.

No code changed.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

Merged on top of Roman's very similar cleanups.
(In other words: Blame John for the merge screwups).

Signed-off-by: John Stultz <johnstul@us.ibm.com>


Index: linux-2.6/kernel/time/ntp.c
===================================================================
--- linux-2.6.orig/kernel/time/ntp.c 2008-03-14 19:21:02.000000000 -0700
+++ linux-2.6/kernel/time/ntp.c 2008-03-14 20:10:41.000000000 -0700
@@ -1,13 +1,10 @@
/*
- * linux/kernel/time/ntp.c
- *
* NTP state machine interfaces and logic.
*
* This code was mainly moved from kernel/timer.c and kernel/time.c
* Please see those files for relevant copyright info and historical
* changelogs.
*/
-
#include <linux/mm.h>
#include <linux/time.h>
#include <linux/timer.h>
@@ -22,32 +19,35 @@
/*
* Timekeeping variables
*/
-unsigned long tick_usec = TICK_USEC; /* USER_HZ period (usec) */
-unsigned long tick_nsec; /* ACTHZ period (nsec) */
-u64 tick_length;
-static u64 tick_length_base;
-
-static struct hrtimer leap_timer;
-
-#define MAX_TICKADJ 500 /* microsecs */
-#define MAX_TICKADJ_SCALED (((u64)(MAX_TICKADJ * NSEC_PER_USEC) << \
- NTP_SCALE_SHIFT) / NTP_INTERVAL_FREQ)
+unsigned long tick_usec = TICK_USEC; /* USER_HZ period (usec) */
+unsigned long tick_nsec; /* ACTHZ period (nsec) */
+u64 tick_length;
+static u64 tick_length_base;
+static const long max_tickadj = 500; /* (usec) */
+
+static struct hrtimer leap_timer;

/*
* phase-lock loop variables
*/
/* TIME_ERROR prevents overwriting the CMOS clock */
-static int time_state = TIME_OK; /* clock synchronization status */
-int time_status = STA_UNSYNC; /* clock status bits */
-static long time_tai; /* TAI offset (s) */
-static s64 time_offset; /* time adjustment (ns) */
-static long time_constant = 2; /* pll time constant */
-long time_maxerror = NTP_PHASE_LIMIT; /* maximum error (us) */
-long time_esterror = NTP_PHASE_LIMIT; /* estimated error (us) */
-static s64 time_freq; /* frequency offset (scaled ns/s)*/
-static long time_reftime; /* time at last adjustment (s) */
-long time_adjust;
-static long ntp_tick_adj;
+static int time_state = TIME_OK; /* clock synch status */
+int time_status = STA_UNSYNC; /* clock status bits */
+static long time_tai; /* TAI offset (s) */
+static s64 time_offset; /* time adjustment (ns) */
+static long time_constant = 2; /* pll time constant */
+long time_maxerror = NTP_PHASE_LIMIT;/* maximum error (us) */
+long time_esterror = NTP_PHASE_LIMIT;/* estimated error (us) */
+static s64 time_freq; /* frequency offset (scaled ns/s)*/
+static long time_reftime; /* time at last adjustment (s) */
+long time_adjust;
+static long ntp_tick_adj;
+
+
+static inline u64 scale_tickadj(u64 adj)
+{
+ return ((adj * NSEC_PER_USEC) << NTP_SCALE_SHIFT) / NTP_INTERVAL_FREQ;
+}

static void ntp_update_frequency(void)
{
@@ -111,15 +111,15 @@ static void ntp_update_offset(long offse
*/
void ntp_clear(void)
{
- time_adjust = 0; /* stop active adjtime() */
- time_status |= STA_UNSYNC;
- time_maxerror = NTP_PHASE_LIMIT;
- time_esterror = NTP_PHASE_LIMIT;
+ time_adjust = 0; /* stop active adjtime() */
+ time_status |= STA_UNSYNC;
+ time_maxerror = NTP_PHASE_LIMIT;
+ time_esterror = NTP_PHASE_LIMIT;

ntp_update_frequency();

- tick_length = tick_length_base;
- time_offset = 0;
+ tick_length = tick_length_base;
+ time_offset = 0;
}

/*
@@ -136,28 +136,32 @@ static enum hrtimer_restart ntp_leap_sec
switch (time_state) {
case TIME_OK:
break;
+
case TIME_INS:
xtime.tv_sec--;
wall_to_monotonic.tv_sec++;
time_state = TIME_OOP;
- printk(KERN_NOTICE "Clock: "
- "inserting leap second 23:59:60 UTC\n");
+ printk(KERN_NOTICE
+ "Clock: inserting leap second 23:59:60 UTC\n");
leap_timer.expires = ktime_add_ns(leap_timer.expires,
NSEC_PER_SEC);
res = HRTIMER_RESTART;
break;
+
case TIME_DEL:
xtime.tv_sec++;
time_tai--;
wall_to_monotonic.tv_sec--;
time_state = TIME_WAIT;
- printk(KERN_NOTICE "Clock: "
- "deleting leap second 23:59:59 UTC\n");
+ printk(KERN_NOTICE
+ "Clock: deleting leap second 23:59:59 UTC\n");
break;
+
case TIME_OOP:
time_tai++;
time_state = TIME_WAIT;
/* fall through */
+
case TIME_WAIT:
if (!(time_status & (STA_INS | STA_DEL)))
time_state = TIME_OK;
@@ -193,21 +197,20 @@ void second_overflow(void)
* Compute the phase adjustment for the next second. The offset is
* reduced by a fixed factor times the time constant.
*/
- tick_length = tick_length_base;
- time_adj = shift_right(time_offset, SHIFT_PLL + time_constant);
- time_offset -= time_adj;
- tick_length += time_adj;
+ tick_length = tick_length_base;
+ time_adj = shift_right(time_offset, SHIFT_PLL + time_constant);
+ time_offset -= time_adj;
+ tick_length += time_adj;

if (unlikely(time_adjust)) {
- if (time_adjust > MAX_TICKADJ) {
- time_adjust -= MAX_TICKADJ;
- tick_length += MAX_TICKADJ_SCALED;
- } else if (time_adjust < -MAX_TICKADJ) {
- time_adjust += MAX_TICKADJ;
- tick_length -= MAX_TICKADJ_SCALED;
+ if (time_adjust > max_tickadj) {
+ time_adjust -= max_tickadj;
+ tick_length += scale_tickadj(max_tickadj);
+ } else if (time_adjust < -max_tickadj) {
+ time_adjust += max_tickadj;
+ tick_length -= scale_tickadj(max_tickadj);
} else {
- tick_length += (s64)(time_adjust * NSEC_PER_USEC /
- NTP_INTERVAL_FREQ) << NTP_SCALE_SHIFT;
+ tick_length += scale_tickadj(time_adjust);
time_adjust = 0;
}
}
@@ -216,13 +219,13 @@ void second_overflow(void)
#ifdef CONFIG_GENERIC_CMOS_UPDATE

/* Disable the cmos update - used by virtualization and embedded */
-int no_sync_cmos_clock __read_mostly;
+int no_sync_cmos_clock __read_mostly;

-static void sync_cmos_clock(unsigned long dummy);
+static void sync_cmos_clock(unsigned long unused);

static DEFINE_TIMER(sync_cmos_timer, sync_cmos_clock, 0, 0);

-static void sync_cmos_clock(unsigned long dummy)
+static void sync_cmos_clock(unsigned long unused)
{
struct timespec now, next;
int fail = 1;
@@ -234,12 +237,13 @@ static void sync_cmos_clock(unsigned lon
* This code is run on a timer. If the clock is set, that timer
* may not expire at the correct time. Thus, we adjust...
*/
- if (!ntp_synced())
+ if (!ntp_synced()) {
/*
* Not synced, exit, do not restart a timer (if one is
* running, let it run out).
*/
return;
+ }

getnstimeofday(&now);
if (abs(now.tv_nsec - (NSEC_PER_SEC / 2)) <= tick_nsec / 2)
@@ -271,7 +275,8 @@ static void notify_cmos_timer(void)
static inline void notify_cmos_timer(void) { }
#endif

-/* adjtimex mainly allows reading (and writing, if superuser) of
+/*
+ * adjtimex mainly allows reading (and writing, if superuser) of
* kernel time-keeping variables. used by xntpd.
*/
int do_adjtimex(struct timex *txc)
@@ -293,10 +298,11 @@ int do_adjtimex(struct timex *txc)
}

/* if the quartz is off by more than 10% something is VERY wrong ! */
- if (txc->modes & ADJ_TICK)
+ if (txc->modes & ADJ_TICK) {
if (txc->tick < 900000/USER_HZ ||
txc->tick > 1100000/USER_HZ)
return -EINVAL;
+ }

if (time_state != TIME_OK && txc->modes & ADJ_STATUS)
hrtimer_cancel(&leap_timer);



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