[PATCH 06/21] ntp: Read reference time only once

From: Anna-Maria Behnsen
Date: Wed Sep 11 2024 - 09:20:25 EST


From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

The reference time is required twice in ntp_update_offset(). It will not
change in the meantime as the calling code holds the timekeeper lock. Read
it only once and store it into a local variable.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Anna-Maria Behnsen <anna-maria@xxxxxxxxxxxxx>
---
kernel/time/ntp.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index ef758aafdfd5..477cb08062bc 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -283,9 +283,8 @@ static inline s64 ntp_update_offset_fll(s64 offset64, long secs)

static void ntp_update_offset(long offset)
{
- s64 freq_adj;
- s64 offset64;
- long secs;
+ s64 freq_adj, offset64;
+ long secs, real_secs;

if (!(time_status & STA_PLL))
return;
@@ -303,11 +302,12 @@ static void ntp_update_offset(long offset)
* Select how the frequency is to be controlled
* and in which mode (PLL or FLL).
*/
- secs = (long)(__ktime_get_real_seconds() - time_reftime);
+ real_secs = __ktime_get_real_seconds();
+ secs = (long)(real_secs - time_reftime);
if (unlikely(time_status & STA_FREQHOLD))
secs = 0;

- time_reftime = __ktime_get_real_seconds();
+ time_reftime = real_secs;

offset64 = offset;
freq_adj = ntp_update_offset_fll(offset64, secs);

--
2.39.2