| From: Thomas Gleixner <tglx@linutronix.de> |
| Date: Thu, 12 Oct 2017 16:14:22 +0200 |
| Subject: rtmutex: Provide rt_mutex_slowlock_locked() |
| |
| This is the inner-part of rt_mutex_slowlock(), required for rwsem-rt. |
| |
| Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
| Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> |
| --- |
| kernel/locking/rtmutex.c | 67 ++++++++++++++++++++++------------------ |
| kernel/locking/rtmutex_common.h | 7 ++++ |
| 2 files changed, 45 insertions(+), 29 deletions(-) |
| |
| --- a/kernel/locking/rtmutex.c |
| +++ b/kernel/locking/rtmutex.c |
| @@ -1243,35 +1243,16 @@ static void rt_mutex_handle_deadlock(int |
| } |
| } |
| |
| -/* |
| - * Slow path lock function: |
| - */ |
| -static int __sched |
| -rt_mutex_slowlock(struct rt_mutex *lock, int state, |
| - struct hrtimer_sleeper *timeout, |
| - enum rtmutex_chainwalk chwalk) |
| +int __sched rt_mutex_slowlock_locked(struct rt_mutex *lock, int state, |
| + struct hrtimer_sleeper *timeout, |
| + enum rtmutex_chainwalk chwalk, |
| + struct rt_mutex_waiter *waiter) |
| { |
| - struct rt_mutex_waiter waiter; |
| - unsigned long flags; |
| - int ret = 0; |
| - |
| - rt_mutex_init_waiter(&waiter); |
| - |
| - /* |
| - * Technically we could use raw_spin_[un]lock_irq() here, but this can |
| - * be called in early boot if the cmpxchg() fast path is disabled |
| - * (debug, no architecture support). In this case we will acquire the |
| - * rtmutex with lock->wait_lock held. But we cannot unconditionally |
| - * enable interrupts in that early boot case. So we need to use the |
| - * irqsave/restore variants. |
| - */ |
| - raw_spin_lock_irqsave(&lock->wait_lock, flags); |
| + int ret; |
| |
| /* Try to acquire the lock again: */ |
| - if (try_to_take_rt_mutex(lock, current, NULL)) { |
| - raw_spin_unlock_irqrestore(&lock->wait_lock, flags); |
| + if (try_to_take_rt_mutex(lock, current, NULL)) |
| return 0; |
| - } |
| |
| set_current_state(state); |
| |
| @@ -1279,16 +1260,16 @@ rt_mutex_slowlock(struct rt_mutex *lock, |
| if (unlikely(timeout)) |
| hrtimer_start_expires(&timeout->timer, HRTIMER_MODE_ABS); |
| |
| - ret = task_blocks_on_rt_mutex(lock, &waiter, current, chwalk); |
| + ret = task_blocks_on_rt_mutex(lock, waiter, current, chwalk); |
| |
| if (likely(!ret)) |
| /* sleep on the mutex */ |
| - ret = __rt_mutex_slowlock(lock, state, timeout, &waiter); |
| + ret = __rt_mutex_slowlock(lock, state, timeout, waiter); |
| |
| if (unlikely(ret)) { |
| __set_current_state(TASK_RUNNING); |
| - remove_waiter(lock, &waiter); |
| - rt_mutex_handle_deadlock(ret, chwalk, &waiter); |
| + remove_waiter(lock, waiter); |
| + rt_mutex_handle_deadlock(ret, chwalk, waiter); |
| } |
| |
| /* |
| @@ -1296,6 +1277,34 @@ rt_mutex_slowlock(struct rt_mutex *lock, |
| * unconditionally. We might have to fix that up. |
| */ |
| fixup_rt_mutex_waiters(lock); |
| + return ret; |
| +} |
| + |
| +/* |
| + * Slow path lock function: |
| + */ |
| +static int __sched |
| +rt_mutex_slowlock(struct rt_mutex *lock, int state, |
| + struct hrtimer_sleeper *timeout, |
| + enum rtmutex_chainwalk chwalk) |
| +{ |
| + struct rt_mutex_waiter waiter; |
| + unsigned long flags; |
| + int ret = 0; |
| + |
| + rt_mutex_init_waiter(&waiter); |
| + |
| + /* |
| + * Technically we could use raw_spin_[un]lock_irq() here, but this can |
| + * be called in early boot if the cmpxchg() fast path is disabled |
| + * (debug, no architecture support). In this case we will acquire the |
| + * rtmutex with lock->wait_lock held. But we cannot unconditionally |
| + * enable interrupts in that early boot case. So we need to use the |
| + * irqsave/restore variants. |
| + */ |
| + raw_spin_lock_irqsave(&lock->wait_lock, flags); |
| + |
| + ret = rt_mutex_slowlock_locked(lock, state, timeout, chwalk, &waiter); |
| |
| raw_spin_unlock_irqrestore(&lock->wait_lock, flags); |
| |
| --- a/kernel/locking/rtmutex_common.h |
| +++ b/kernel/locking/rtmutex_common.h |
| @@ -15,6 +15,7 @@ |
| |
| #include <linux/rtmutex.h> |
| #include <linux/sched/wake_q.h> |
| +#include <linux/sched/debug.h> |
| |
| /* |
| * This is the control structure for tasks blocked on a rt_mutex, |
| @@ -159,6 +160,12 @@ extern bool __rt_mutex_futex_unlock(stru |
| struct wake_q_head *wqh); |
| |
| extern void rt_mutex_postunlock(struct wake_q_head *wake_q); |
| +/* RW semaphore special interface */ |
| + |
| +int __sched rt_mutex_slowlock_locked(struct rt_mutex *lock, int state, |
| + struct hrtimer_sleeper *timeout, |
| + enum rtmutex_chainwalk chwalk, |
| + struct rt_mutex_waiter *waiter); |
| |
| #ifdef CONFIG_DEBUG_RT_MUTEXES |
| # include "rtmutex-debug.h" |