diff options
| -rw-r--r-- | fs/timerfd.c | 10 | ||||
| -rw-r--r-- | kernel/time/hrtimer.c | 2 | ||||
| -rw-r--r-- | kernel/time/timer.c | 8 |
3 files changed, 18 insertions, 2 deletions
diff --git a/fs/timerfd.c b/fs/timerfd.c index 053818dd6c18..9ae4abb4110b 100644 --- a/fs/timerfd.c +++ b/fs/timerfd.c @@ -390,6 +390,11 @@ SYSCALL_DEFINE2(timerfd_create, int, clockid, int, flags) clockid != CLOCK_BOOTTIME_ALARM)) return -EINVAL; + if (!capable(CAP_WAKE_ALARM) && + (clockid == CLOCK_REALTIME_ALARM || + clockid == CLOCK_BOOTTIME_ALARM)) + return -EPERM; + ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); if (!ctx) return -ENOMEM; @@ -433,6 +438,11 @@ static int do_timerfd_settime(int ufd, int flags, return ret; ctx = f.file->private_data; + if (!capable(CAP_WAKE_ALARM) && isalarm(ctx)) { + fdput(f); + return -EPERM; + } + timerfd_setup_cancel(ctx, flags); /* diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c index e99df0ff1d42..d13c9aebf7a3 100644 --- a/kernel/time/hrtimer.c +++ b/kernel/time/hrtimer.c @@ -177,7 +177,7 @@ hrtimer_check_target(struct hrtimer *timer, struct hrtimer_clock_base *new_base) #endif } -#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON) +#ifdef CONFIG_NO_HZ_COMMON static inline struct hrtimer_cpu_base *get_target_base(struct hrtimer_cpu_base *base, int pinned) diff --git a/kernel/time/timer.c b/kernel/time/timer.c index 3a95f9728778..67dd6103003a 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -1702,9 +1702,15 @@ static void __sched do_usleep_range(unsigned long min, unsigned long max) } /** - * usleep_range - Drop in replacement for udelay where wakeup is flexible + * usleep_range - Sleep for an approximate time * @min: Minimum time in usecs to sleep * @max: Maximum time in usecs to sleep + * + * In non-atomic context where the exact wakeup time is flexible, use + * usleep_range() instead of udelay(). The sleep improves responsiveness + * by avoiding the CPU-hogging busy-wait of udelay(), and the range reduces + * power usage by allowing hrtimers to take advantage of an already- + * scheduled interrupt instead of scheduling a new one just for this sleep. */ void __sched usleep_range(unsigned long min, unsigned long max) { |