2011-02-01 13:52:57

by Thomas Gleixner

Subject: [patch 23/28] ntp: Add ADJ_SETOFFSET mode bit

From: Richard Cochran <[email protected]>

This patch adds a new mode bit into the timex structure. When set, the bit
instructs the kernel to add the given time value to the current time.

Signed-off-by: Richard Cochran <[email protected]>
Cc: John Stultz <[email protected]>
LKML-Reference: <2f7ed6bce83c23e4b7e4530794f0aa175df31a39.1296124770.git.richard.cochran@omicron.at>
Signed-off-by: Thomas Gleixner <[email protected]>
---
include/linux/timex.h | 3 ++-
kernel/time/ntp.c | 11 +++++++++++
2 files changed, 13 insertions(+), 1 deletion(-)

Index: linux-2.6-tip/include/linux/timex.h
===================================================================
--- linux-2.6-tip.orig/include/linux/timex.h
+++ linux-2.6-tip/include/linux/timex.h
@@ -73,7 +73,7 @@ struct timex {
long tolerance; /* clock frequency tolerance (ppm)
* (read only)
*/
- struct timeval time; /* (read only) */
+ struct timeval time; /* (read only, except for ADJ_SETOFFSET) */
long tick; /* (modified) usecs between clock ticks */

long ppsfreq; /* pps frequency (scaled ppm) (ro) */
@@ -102,6 +102,7 @@ struct timex {
#define ADJ_STATUS 0x0010 /* clock status */
#define ADJ_TIMECONST 0x0020 /* pll time constant */
#define ADJ_TAI 0x0080 /* set TAI offset */
+#define ADJ_SETOFFSET 0x0100 /* add 'time' to current time */
#define ADJ_MICRO 0x1000 /* select microsecond resolution */
#define ADJ_NANO 0x2000 /* select nanosecond resolution */
#define ADJ_TICK 0x4000 /* tick value */
Index: linux-2.6-tip/kernel/time/ntp.c
===================================================================
--- linux-2.6-tip.orig/kernel/time/ntp.c
+++ linux-2.6-tip/kernel/time/ntp.c
@@ -648,6 +648,17 @@ int do_adjtimex(struct timex *txc)
hrtimer_cancel(&leap_timer);
}

+ if (txc->modes & ADJ_SETOFFSET) {
+ struct timespec delta;
+ if ((unsigned long)txc->time.tv_usec >= NSEC_PER_SEC)
+ return -EINVAL;
+ delta.tv_sec = txc->time.tv_sec;
+ delta.tv_nsec = txc->time.tv_usec;
+ if (!(txc->modes & ADJ_NANO))
+ delta.tv_nsec *= 1000;
+ timekeeping_inject_offset(&delta);
+ }
+
getnstimeofday(&ts);

write_seqlock_irq(&xtime_lock);

2011-02-01 21:30:26

by john stultz

Subject: Re: [patch 23/28] ntp: Add ADJ_SETOFFSET mode bit

On Tue, 2011-02-01 at 13:52 +0000, Thomas Gleixner wrote:
> plain text document attachment (ntp-add-adj_setoffset-mode-bit.patch)
> From: Richard Cochran <[email protected]>
>
> This patch adds a new mode bit into the timex structure. When set, the bit
> instructs the kernel to add the given time value to the current time.
>
> Signed-off-by: Richard Cochran <[email protected]>
> Cc: John Stultz <[email protected]>
> LKML-Reference: <2f7ed6bce83c23e4b7e4530794f0aa175df31a39.1296124770.git.richard.cochran@omicron.at>
> Signed-off-by: Thomas Gleixner <[email protected]>

Acked-by: John Stultz <[email protected]>