[tip: locking/core] time/sched_clock: Use seqcount_latch_t

tip-bot2 for Ahmed S. Darwish
2020-09-10T19:28:52Z

The following commit has been merged into the locking/core branch of tip:

Commit-ID: a690ed07353ec45f056b0a6f87c23a12a59c030d
Gitweb: https://git.kernel.org/tip/a690ed07353ec45f056b0a6f87c23a12a59c030d
Author: Ahmed S. Darwish <a.darwish@linutronix.de>
AuthorDate: Thu, 27 Aug 2020 13:40:40 +02:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Thu, 10 Sep 2020 11:19:29 +02:00

time/sched_clock: Use seqcount_latch_t

Latch sequence counters have unique read and write APIs, and thus
seqcount_latch_t was recently introduced at seqlock.h.

Use that new data type instead of plain seqcount_t. This adds the
necessary type-safety and ensures only latching-safe seqcount APIs are
to be used.

Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200827114044.11173-5-a.darwish@linutronix.de
---
kernel/time/sched_clock.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/time/sched_clock.c b/kernel/time/sched_clock.c
index 8c6b5fe..0642013 100644
--- a/kernel/time/sched_clock.c
+++ b/kernel/time/sched_clock.c
@@ -35,7 +35,7 @@
* into a single 64-byte cache line.
*/
struct clock_data {
- seqcount_t seq;
+ seqcount_latch_t seq;
struct clock_read_data read_data[2];
ktime_t wrap_kt;
unsigned long rate;
@@ -76,7 +76,7 @@ struct clock_read_data *sched_clock_read_begin(unsigned int *seq)

int sched_clock_read_retry(unsigned int seq)
{
- return read_seqcount_retry(&cd.seq, seq);
+ return read_seqcount_latch_retry(&cd.seq, seq);
}

unsigned long long notrace sched_clock(void)