path: root/kernel/time/hrtimer.c
diff options
authorLinus Torvalds <torvalds@linux-foundation.org>2019-12-03 12:20:25 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2019-12-03 12:20:25 -0800
commit043cf46825c102683b1027762c09c7e2b749e5a3 (patch)
tree765765d137ec75e6455d9e8fdc5a4ff94b1cf5e3 /kernel/time/hrtimer.c
parentMerge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip (diff)
parentMerge branch 'timers/urgent' into timers/core, to pick up fix (diff)
Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer updates from Ingo Molnar: "The main changes in the timer code in this cycle were: - Clockevent updates: - timer-of framework cleanups. (Geert Uytterhoeven) - Use timer-of for the renesas-ostm and the device name to prevent name collision in case of multiple timers. (Geert Uytterhoeven) - Check if there is an error after calling of_clk_get in asm9260 (Chuhong Yuan) - ABI fix: Zero out high order bits of nanoseconds on compat syscalls. This got broken a year ago, with apparently no side effects so far. Since the kernel would use random data otherwise I don't think we'd have other options but to fix the bug, even if there was a side effect to applications (Dmitry Safonov) - Optimize ns_to_timespec64() on 32-bit systems: move away from div_s64_rem() which can be slow, to div_u64_rem() which is faster (Arnd Bergmann) - Annotate KCSAN-reported false positive data races in hrtimer_is_queued() users by moving timer->state handling over to the READ_ONCE()/WRITE_ONCE() APIs. This documents these accesses (Eric Dumazet) - Misc cleanups and small fixes" [ I undid the "ABI fix" and updated the comments instead. The reason there were apparently no side effects is that the fix was a no-op. The updated comment is to say _why_ it was a no-op. - Linus ] * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: time: Zero the upper 32-bits in __kernel_timespec on 32-bit time: Rename tsk->real_start_time to ->start_boottime hrtimer: Remove the comment about not used HRTIMER_SOFTIRQ time: Fix spelling mistake in comment time: Optimize ns_to_timespec64() hrtimer: Annotate lockless access to timer->state clocksource/drivers/asm9260: Add a check for of_clk_get clocksource/drivers/renesas-ostm: Use unique device name instead of ostm clocksource/drivers/renesas-ostm: Convert to timer_of clocksource/drivers/timer-of: Use unique device name instead of timer clocksource/drivers/timer-of: Convert last full_name to %pOF
Diffstat (limited to 'kernel/time/hrtimer.c')
1 files changed, 7 insertions, 4 deletions
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 9e20873148c6..8de90ea31280 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -966,7 +966,8 @@ static int enqueue_hrtimer(struct hrtimer *timer,
base->cpu_base->active_bases |= 1 << base->index;
- timer->state = HRTIMER_STATE_ENQUEUED;
+ /* Pairs with the lockless read in hrtimer_is_queued() */
return timerqueue_add(&base->active, &timer->node);
@@ -988,7 +989,8 @@ static void __remove_hrtimer(struct hrtimer *timer,
struct hrtimer_cpu_base *cpu_base = base->cpu_base;
u8 state = timer->state;
- timer->state = newstate;
+ /* Pairs with the lockless read in hrtimer_is_queued() */
+ WRITE_ONCE(timer->state, newstate);
@@ -1013,8 +1015,9 @@ static void __remove_hrtimer(struct hrtimer *timer,
static inline int
remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base, bool restart)
- if (hrtimer_is_queued(timer)) {
- u8 state = timer->state;
+ u8 state = timer->state;
int reprogram;