diff options
Diffstat (limited to 'kernel/time/timer.c')
| -rw-r--r-- | kernel/time/timer.c | 96 |
1 files changed, 46 insertions, 50 deletions
diff --git a/kernel/time/timer.c b/kernel/time/timer.c index 781483c76b17..d6289d8df06b 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -44,7 +44,6 @@ #include <linux/sched/debug.h> #include <linux/slab.h> #include <linux/compat.h> -#include <linux/swait.h> #include <linux/uaccess.h> #include <asm/unistd.h> @@ -198,9 +197,7 @@ EXPORT_SYMBOL(jiffies_64); struct timer_base { raw_spinlock_t lock; struct timer_list *running_timer; -#ifdef CONFIG_PREEMPT_RT_FULL - struct swait_queue_head wait_for_running_timer; -#endif + spinlock_t expiry_lock; unsigned long clk; unsigned long next_expiry; unsigned int cpu; @@ -1189,33 +1186,6 @@ void add_timer_on(struct timer_list *timer, int cpu) } EXPORT_SYMBOL_GPL(add_timer_on); -#ifdef CONFIG_PREEMPT_RT_FULL -/* - * Wait for a running timer - */ -static void wait_for_running_timer(struct timer_list *timer) -{ - struct timer_base *base; - u32 tf = timer->flags; - - if (tf & TIMER_MIGRATING) - return; - - base = get_timer_base(tf); - swait_event_exclusive(base->wait_for_running_timer, - base->running_timer != timer); -} - -# define wakeup_timer_waiters(b) swake_up_all(&(b)->wait_for_running_timer) -#else -static inline void wait_for_running_timer(struct timer_list *timer) -{ - cpu_relax(); -} - -# define wakeup_timer_waiters(b) do { } while (0) -#endif - /** * del_timer - deactivate a timer. * @timer: the timer to be deactivated @@ -1245,14 +1215,8 @@ int del_timer(struct timer_list *timer) } EXPORT_SYMBOL(del_timer); -/** - * try_to_del_timer_sync - Try to deactivate a timer - * @timer: timer to delete - * - * This function tries to deactivate a timer. Upon successful (ret >= 0) - * exit the timer is not queued and the handler is not running on any CPU. - */ -int try_to_del_timer_sync(struct timer_list *timer) +static int __try_to_del_timer_sync(struct timer_list *timer, + struct timer_base **basep) { struct timer_base *base; unsigned long flags; @@ -1260,7 +1224,7 @@ int try_to_del_timer_sync(struct timer_list *timer) debug_assert_init(timer); - base = lock_timer_base(timer, &flags); + *basep = base = lock_timer_base(timer, &flags); if (base->running_timer != timer) ret = detach_if_pending(timer, base, true); @@ -1269,9 +1233,42 @@ int try_to_del_timer_sync(struct timer_list *timer) return ret; } + +/** + * try_to_del_timer_sync - Try to deactivate a timer + * @timer: timer to delete + * + * This function tries to deactivate a timer. Upon successful (ret >= 0) + * exit the timer is not queued and the handler is not running on any CPU. + */ +int try_to_del_timer_sync(struct timer_list *timer) +{ + struct timer_base *base; + + return __try_to_del_timer_sync(timer, &base); +} EXPORT_SYMBOL(try_to_del_timer_sync); #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT_FULL) +static int __del_timer_sync(struct timer_list *timer) +{ + struct timer_base *base; + int ret; + + for (;;) { + ret = __try_to_del_timer_sync(timer, &base); + if (ret >= 0) + return ret; + + /* + * When accessing the lock, timers of base are no longer expired + * and so timer is no longer running. + */ + spin_lock(&base->expiry_lock); + spin_unlock(&base->expiry_lock); + } +} + /** * del_timer_sync - deactivate a timer and wait for the handler to finish. * @timer: the timer to be deactivated @@ -1327,12 +1324,8 @@ int del_timer_sync(struct timer_list *timer) * could lead to deadlock. */ WARN_ON(in_irq() && !(timer->flags & TIMER_IRQSAFE)); - for (;;) { - int ret = try_to_del_timer_sync(timer); - if (ret >= 0) - return ret; - wait_for_running_timer(timer); - } + + return __del_timer_sync(timer); } EXPORT_SYMBOL(del_timer_sync); #endif @@ -1397,11 +1390,15 @@ static void expire_timers(struct timer_base *base, struct hlist_head *head) raw_spin_unlock(&base->lock); call_timer_fn(timer, fn); base->running_timer = NULL; + spin_unlock(&base->expiry_lock); + spin_lock(&base->expiry_lock); raw_spin_lock(&base->lock); } else { raw_spin_unlock_irq(&base->lock); call_timer_fn(timer, fn); base->running_timer = NULL; + spin_unlock(&base->expiry_lock); + spin_lock(&base->expiry_lock); raw_spin_lock_irq(&base->lock); } } @@ -1696,6 +1693,7 @@ static inline void __run_timers(struct timer_base *base) if (!time_after_eq(jiffies, base->clk)) return; + spin_lock(&base->expiry_lock); raw_spin_lock_irq(&base->lock); /* @@ -1723,7 +1721,7 @@ static inline void __run_timers(struct timer_base *base) expire_timers(base, heads + levels); } raw_spin_unlock_irq(&base->lock); - wakeup_timer_waiters(base); + spin_unlock(&base->expiry_lock); } /* @@ -1970,9 +1968,7 @@ static void __init init_timer_cpu(int cpu) base->cpu = cpu; raw_spin_lock_init(&base->lock); base->clk = jiffies; -#ifdef CONFIG_PREEMPT_RT_FULL - init_swait_queue_head(&base->wait_for_running_timer); -#endif + spin_lock_init(&base->expiry_lock); } } |