timekeeping: Fix cross-timestamp interpolation on counter wrap

[ Upstream commit 84dccadd3e2a3f1a373826ad71e5ced5e76b0c00 ]

cycle_between() decides whether get_device_system_crosststamp() will
interpolate for older counter readings.

cycle_between() yields wrong results for a counter wrap-around where after
< before < test, and for the case after < test < before.

Fix the comparison logic.

Fixes: 2c756feb18d9 ("time: Add history to cross timestamp interface supporting slower devices")
Signed-off-by: Peter Hilber <peter.hilber@opensynergy.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: John Stultz <jstultz@google.com>
Link: https://lore.kernel.org/r/20231218073849.35294-2-peter.hilber@opensynergy.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index d9b48f7a35e0dbcf48cb15be33f8875babf8594f..6a8a610b197174567381bf310766698eb31f0793 100644 (file)
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -1173,7 +1173,7 @@ static bool cycle_between(u64 before, u64 test, u64 after)
 {
        if (test > before && test < after)
                return true;
-       if (test < before && before > after)
+       if (before > after && (test > before || test < after))
                return true;
        return false;
 }