[GIT pull] timers/urgent for 5.4-rc4

From: Thomas Gleixner
Date: Sun Oct 20 2019 - 06:15:09 EST


Linus,

please pull the latest timers-urgent-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git timers-urgent-for-linus

up to: ff229eee3d89: hrtimer: Annotate lockless access to timer->base

A single commit annotating the lockcless access to timer->base with
READ_ONCE() and adding the WRITE_ONCE() counterparts for completeness.

Thanks,

tglx

------------------>
Eric Dumazet (1):
hrtimer: Annotate lockless access to timer->base


kernel/time/hrtimer.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 0d4dc241c0fb..65605530ee34 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -164,7 +164,7 @@ struct hrtimer_clock_base *lock_hrtimer_base(const struct hrtimer *timer,
struct hrtimer_clock_base *base;

for (;;) {
- base = timer->base;
+ base = READ_ONCE(timer->base);
if (likely(base != &migration_base)) {
raw_spin_lock_irqsave(&base->cpu_base->lock, *flags);
if (likely(base == timer->base))
@@ -244,7 +244,7 @@ switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base,
return base;

/* See the comment in lock_hrtimer_base() */
- timer->base = &migration_base;
+ WRITE_ONCE(timer->base, &migration_base);
raw_spin_unlock(&base->cpu_base->lock);
raw_spin_lock(&new_base->cpu_base->lock);

@@ -253,10 +253,10 @@ switch_hrtimer_base(struct hrtimer *timer, struct hrtimer_clock_base *base,
raw_spin_unlock(&new_base->cpu_base->lock);
raw_spin_lock(&base->cpu_base->lock);
new_cpu_base = this_cpu_base;
- timer->base = base;
+ WRITE_ONCE(timer->base, base);
goto again;
}
- timer->base = new_base;
+ WRITE_ONCE(timer->base, new_base);
} else {
if (new_cpu_base != this_cpu_base &&
hrtimer_check_target(timer, new_base)) {