diff options
| author | Sven Schnelle <svens@linux.ibm.com> | 2025-07-03 13:50:27 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-08-28 16:28:21 +0200 |
| commit | 3f8bcc32050ec65c9399391001e531eb3f2223b9 (patch) | |
| tree | d1673b10796cd7a92536defe454131ae9d5ce64e /arch/s390 | |
| parent | 11238e68cb6823d11b808e86ac33fe4700a382e4 (diff) | |
s390/stp: Remove udelay from stp_sync_clock()
[ Upstream commit b367017cdac21781a74eff4e208d3d38e1f38d3f ]
When an stp sync check is handled on a system with multiple
cpus each cpu gets a machine check but only the first one
actually handles the sync operation. All other CPUs spin
waiting for the first one to finish with a short udelay().
But udelay can't be used here as the first CPU modifies tod_clock_base
before performing the sync op. During this timeframe
get_tod_clock_monotonic() might return a non-monotonic time.
The time spent waiting should be very short and udelay is a busy loop
anyways, therefore simply remove the udelay.
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch/s390')
| -rw-r--r-- | arch/s390/kernel/time.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/s390/kernel/time.c b/arch/s390/kernel/time.c index d34d3548c046..086d3e3ffdea 100644 --- a/arch/s390/kernel/time.c +++ b/arch/s390/kernel/time.c @@ -579,7 +579,7 @@ static int stp_sync_clock(void *data) atomic_dec(&sync->cpus); /* Wait for in_sync to be set. */ while (READ_ONCE(sync->in_sync) == 0) - __udelay(1); + ; } if (sync->in_sync != 1) /* Didn't work. Clear per-cpu in sync bit again. */ |